PALEOCEANOGRAPHY,
VOL. 10,
10,NO.
NO. 3,
3, PAGES
PAGES 373-394,
373-394, JUNE
JUNE 1995
PALEOCEANOGRAPHY,
VOL.
1995
A fi13C
13C record
Water
A
recordof
of Upper
Upper North
North Atlantic
Atlantic Deep
DeepWater
during the
during
thepast
past2.6
2.6 million
million years
years
D.
D.W.
W.Oppo,'
Oppo,
•M.
M.E.E.Raymo,2
Raymo,
2G.
G.P.
P.Lohmann,'
Lohmann,
1A.
A.C.C.Mix,3
Mix,3J.J.D.
D.Wright,4
Wright,
4
and W.
W. L.
L. Prell5
Prell 5
Abstract.
foraminiferal
ö'3C
data
Sea
Abstract.Benthic
Benthic
foraminiferal
813C
datafrom
fromsite
site502
502in
inthe
theCaribbean
Caribbean
Sea
(sill
depth
1800
m)
indicate
that
throughout
the
past
2.6
m.y.,
glacial
6'3C
values
in
(silldepth
--1800
m)indicate
thatthroughout
thepast
2.6m.y.,
glacial
8•3C
values
inthe
the
middepth
Atlantic
were
higher
during
glaciations
than
interglaciations.
This
is
interpreted
as
middepth
Atlantic
werehigher
during
glaciations
thaninterglaciations.
Thisisinterpreted
as
indicating
a
greater
proportion
of
Upper
North
Atlantic
Deep
Water
(UNADW)
relative
to
indicating
a greater
proportion
ofUpper
NorthAtlantic
DeepWater(UNADW)
relative
to
southern source
waters during
during glaciations.
glaciations. The
of
interglaciations
southern
source
waters
Thecontribution
contribution
ofUNADW
UNADWduring
during
interglaciations
contribution
during
to
the
middepth
Atlantic
remained
approximately
constant,
and
the
tothemiddepth
Atlantic
remained
approximately
constant,
andthecontribution
during
glaciations
may
been
as
as
in
than
in
glaciations
mayhave
have
been
asmuch
much
as10
10%
%higher
higher
inthe
thelate
latePleistocene
Pleistocene
than
inthe
thelate
late
Lower
Pliocene. This
increase
isisin
contrast
to
in
Pliocene.
Thissmall
small
increase
instriking
striking
contrast
tothe
themuch
muchlarger
largerdecrease
decrease
in glacial
glacialLower
80%
North
Atlantic
Deep
Water
(LNADW)
contribution
relative
to
southern
sources,
from
about
NorthAtlantic
Deep
Water
(LNADW)
contribution
relative
tosouthern
sources,
fromabout
80%
intensification
over
to
20%,
over
past 2.6
m.y. Glacial
toabout
about
20%,that
thatoccurred
occurred
overthe
thepast
2.6m.y.
Glacial
intensification
overthe
thepast
past2.6
2.6m.y.
m.y.
by
the
upper
limb
of
the
was
probably
coupled
with
a
decrease
in
northward
heat
transport
wasprobably
coupled
withadecrease
innorthward
heat
transport
bytheupper
limboftheNorth
North
Atlantic
circulation
cell,
suggested
on
of
alone.
Atlantic
circulation
cell,as
aswas
waspreviously
previously
suggested
onthe
thebasis
basis
ofaaLNADW
LNADWrecord
record
alone.
0.2
Late
(1
ö'3C
values
in
Sea
approximately
LatePleistocene
Pleistocene
(1Ma-present)
Ma-present)
813C
values
inthe
theCaribbean
Caribbean
Seawere
were
approximately
0.2%
%0
the mean
higher
than
they
were
from
2.6
to
2.0
Ma.
The
ö'3C
rise
is
not
due
to
an
increase
in
higher
than
theywere
from2.6to2.0Ma.The813C
riseisnotduetoanincrease
inthemean
in the
the proportion
proportion of
of high-8•3C
high-'3C
ocean
8'3C
value,
nor
can
ititbe
attributed
to
ocean
8•3C
value,
nor
can
beentirely
entirely
attributed
toan
anincrease
increase
in
surface
source
waters
must
have
contributed
source
waters.
An
increase
in
the
ö'3C
value
of
the
source
waters.An increase
in the813C
valueofthesurface
source
waters
musthavecontributed
'3C rise.
rise.
the 8•3C
to the
Introduction
Introduction
Over
model
Over the
thepast
pastdecade,
decade,aa generalized
generalized
modelfor
forlate
lateQuaternary
Quaternary
deep Atlantic
has
6'3C values
and lower
lower Cd
Cd concentrations
concentrations
deep
Atlantic
hashigher
higher/5•3C
values
and
than the
than
the deep
deepPacific.
Pacific.
Studies
ö'3C and
Studiesof
of/5•3C
andCd/Ca
Cd/Cavalues
valuesof
of benthic
benthicforaminifera
foraminiferafrom
from
glacial-interglacial
changes in
glacial-interglacial changes
in thermohaline
thermohalinecirculation
circulation has
has
upper Pleistocene
upper
Pleistocenesections
sectionsof
of deep-sea
deep-seacores
coreshave
haveshown
shownthat
that
cadmium/calcium(Cd/Ca)
cadmium/calcium (Cd/Ca) values
valuesof
of benthic
benthicforaminifera
foraminifera from
from
deep-sea
cores.
The
utility
of
these
two
geochemical
proxies
deep-seacores. The utility of thesetwo geochemical
proxiesis
is
based on
that
of
813C
based
onthe
theobservation
observation
thatthe
thedistribution
distribution
of/5
•3Cand
andCd
Cd is
is
leaving high
ö'3C values
in
surface
waters
and
leaving
high/5•3C
values
innutrient-poor
nutrient-poor
surface
waters
and
Like
lowering /5•3C
ö'3C values
nutrient-rich
waters.
lowering
valuesin
indeep,
deep,
nutrient-rich
waters. Like
km) of
kin)
of North
North Atlantic
AtlanticDeep
DeepWater
Water(Lower
(LowerNADW;
NADW; LNADW)
LNADW) is
is
drastically reduced
drastically
reducedand
and that
thatproduction
productionof
of waters
watersabove
above22 km,
km,
Upper
[e.g.,
UpperNADW
NADW (UNADW),
(UNADW), is
isenhanced
enhanced
[e.g.,Boyle
Boyleand
andKeigwin,
Keigwin,
1987;
Curry et
Modeling
1987; Curry
et al.,
al., 1988;
1988; Duplessy
Duplessy et
et al.,
al., 1988].
1988]. Modeling
studies
studiessuggest
suggestthat
thatduring
duringglaciations,
glaciations,atmospheric
atmosphericcirculation
circulation
patterns
of
patternsresulting
resultingfrom
fromthe
thepresence
presence
of the
thelarge
largeNorth
NorthAmerican
American
ice
ice sheets
sheetsmay
may have
havecooled
cooledNorth
North Atlantic
Atlantic surface
surfacewaters
waters
[Manabe
[Manabe and
and Broccoli,
Broccoli,1985;
1985;Keffer
Keffer et
et al.,
al., 1988].
1988]. Thus,
Thus, sea
sea
nutrients,
is
nutrients,Cd
Cd is
is depleted
depletedin
in surface
surfacewaters,
waters,and
andits
its distribution
distributionis
apparently
also
apparently
alsocoupled
coupledto
to organic
organicmatter
mattercycling
cycling(see
(seereview
reviewby
by
Boyle
and references
references therein).
therein). Thus,
the
Boyle [19881
[1988] and
Thus,because
because
thedeep
deep
Atlantic
AtlanticOcean
Oceanis
is nutrient-poor
nutrient-poorrelative
relativeto
tothe
thePacific
PacificOcean,
Ocean,the
the
surface
(SST)
surfacetemperature
temperature
(SST)variability
variabilitymay
maylink
linkice
icevolume
volumeand
and
deep
on
timescales. With
deepocean
oceancirculation
circulation
onglacial-interglacial
glacial-interglacial
timescales.
With
cooler
evaporation,
production
of
coolersurface
surfacewaters
watersand
andreduced
reduced
evaporation,
production
of less
less
dense
UNADW
may
be
favored
over
the
production
of
LNADW
denseUNADW maybe favoredovertheproduction
of LNADW
emerged,
largey based
isotope
(6'3C)
during glaciations,
the production
production of
of the
the deeper
deeper components
components(>
(>22
emerged,largely
basedon
oncarbon
carbon
isotope
(5•3C)and
and during
glaciations,the
correlated to
to that
correlated
that of
of nutrients
nutrients in
in the
themodern
modernocean
ocean[e.g.,
[e.g.,
Kroopnick, 1985;
1985;Boyle,
Boyle,1988].
1988]. Low-•5•3C
Low-'3C organic
matter
formed
Kroopnick,
organic
matter
formed
in
in surface
surfacewater
water is
is oxidized
oxidizedand
andremineralized
remineralizedin
in the
the deep
deepocean,
ocean,
[Boyle
and Keigwin,
[Boyleand
Keigwin,1987].
1987].
Studies
Studies of
of Plio-Pleistocene
Plio-Pleistocene climatic
climatic and
andoceanographic
oceanographic
'Woods Hole
Oceanographic
Institution,
Woods
Hole,
Massachusetts.
•Woods
Hole
Oceanographic
Institution,
Woods
Hole,
Massachusetts.
evolution
model
for
evolutionhave
havebuilt
builton
onthe
thegeneralized
generalized
modeldeveloped
developed
forthe
the
2Department
of Earth,
and
Science,
2Department
of
Earth,Atmospheric
Atmospheric
andPlanetary
Planetary
Science, late
late
Quatemary.
Oxygen
isotopic
data
and
ice-rafted
detritus
Quaternary.
Oxygen
isotopic
data
and
ice-rafted
detritus
Massachusetts
Institute
of
Technology,
Cambridge.
Massachusetts
Instituteof Technology,Cambridge.
(IRD) indicate
ice
indicatethat
thatcontinental
continental
ice growth
growthand
andregional
regionalcooling
cooling
3College
of Oceanography,
Oceanography, Oregon
State
University,
Corvallis.
3College
of
Oregon
State
University,
Corvallis.
4Sawyer
Environmental Research
Center,
University
of
Orono.
4Sawyer
Environmental
Research
Center,
University
ofMaine,
Maine,
Orono.
began
hemisphere at
at -3.2
3.2 Ma
1972;
beganin
in the
thenorthern
northern
hemisphere
Ma[Berggren,
[Berggren,
1972;
and
Poore and
5Department
of Geological
Science,
Brown
University,
Providence,
andBerggren,
Berggren,1975;
1975; Shackleton
Shackleton
andOpdyke,
Opdyke,1977;
1977;
5Department
of
Geological
Science,
Brown
University,
Providence,Poore
Rhode
Rhode Island.
Island.
Keigwin, 1987; Keigwin and Thunnell, 1979; Loubere, 1988;
Copyright
Union.
Copyright1995
1995by
by the
theAmerican
AmericanGeophysical
Geophysical
Union.
Paper
Papernumber
number95PA00332.
95PA00332.
0883-8305/95/95 PA-00332510.00
PA-00332$l0.00
0883-8305/95/95
Keigwin,1987;Keigwinand Thunnell,1979;Loubere,1988;
Thunnell
and Williams,
1983; Ruddiman
Ruddiman et
et al.,
al., 1986;
et
Thunnelland
Williams, 1983;
1986; Raymo
Raymo et
al.,
at
al., 1986,
1986,1989],
1989],culminating
culminating
at 2.57
2.57 m.y.
m.y.BP
BP with
withthree
threeglacial
glacial
episodes
having
IRD
in the
episodes
havingwidespread
widespread
IRD deposition
deposition
in
theopen
openNorth
North
Atlantic
(stages
100,
98,
and
96)
and
large
increases
in 8'O
Atlantic
(stages
100,98,and96)andlargeincreases
in
[Shackleton et
et al.,
al., 1984;
et al.,
of
[Shackleton
1984;Raymo
Raymoet
al., 1989]
1989](the
(thechronology
chronology
of
OPPO ET AL.: A 613C
RECORD OF
OF UPPER
UPPER NORTH
NORTH ATLANTIC
ATLANTIC DEEP
DEEP WATER
WATER
OPPO
fil3CRECORD
374
374
Raymo
et al.
al. [1990,
changes
in
Raymoet
[1990,1992]
1992]examined
examined
changes
inö'3C
6•3Cgradients
gradients
between
the
North
Atlantic
and
deep
Pacific
over
betweenthe North Atlantic and deepPacific over the
the past
past3.2
3.2
Table 1.
Table
1. Locations
Locations of
of Cores
Cores Discussed
Discussed in
in Text
Text
Site
Site Latitude
Latitude Longitude
LongitudeDepth,
Depth,m
m
849
849
0°N
0øN
111 øW
°W
111
3851
3851
552
552
56°N
56øN
23°W
23øW
2301
2301
607
607
502
502
610
610
643
643
644
644
677
677
41°N
41øN
33°W
33øW
80°W
80øW
18°W
18øW
3427
3427
1 1°N
11
øN
54°N
54øN
68°N
68øN
67°N
67øN
l°N
1øN
3051
3051
2417
2417
2780
2780
l°E
1
øE
4°E
4øE
84°W
84øW
1226
1226
3461
3461
Region
Region
my.
m.y. using
usinghigh
highresolution
resolutionrecords
recordsfrom
from Deep
DeepSea
SeaDrilling
Drilling
Project
Project (DSDP)
(DSDP) sites
sites552
552 (middepth
(middepthNorth
North Atlantic)
Atlantic) and
and607
607
eastern
easternequatorial
equatorial
Pacific
Pacific
middepth
middepth
North
North Atlantic
Atlantic
deep
deepNorth
NorthAtlantic
Atlantic
Caribbean
Caribbean Sea
North
North Atlantic
Atlantic
Norwegian
NorwegianSea
Sea
Norwegian
NorwegianSea
Sea
eastern
easternequatorial
equatorial
Pacific
Pacific
(deep
(deepNorth
North Atlantic)
Atlantic) and
andOcean
OceanDrilling
Drilling Program
Program(ODP)
(ODP) site
site
677
(Table 1,
I, Figure
677 (deep
(deep equatorial
equatorial Pacific)
Pacific) (Table
Figure 1).
1). They
They
documented
an
in
of
nutrientdocumented
anincrease
increase
inthe
theproportion
proportion
oflow-ö'3C,
low-6•3C,
nutrientrich,
rich, Pacific-like
Pacific-like waters
waters in
in the
thedeep
deepNorth
NorthAtlantic
Atlantic which
which
correlated
correlatedwith
with the
thegradual
gradualincrease
increasein
in glacial
glacialseverity,
severity,although
although
they
also
found
that
LNADW
production
was
partially
decoupled
theyalsofoundthatLNADW productionwaspartiallydecoupled
from
longer
from ice
ice volume
volumeon
ontimescales
timescales
longerthan
than100,000
100,000years.
years. In
In
Data from
the
four
sites
listed are
primary data
data sets
sets for
for
Data
from
thefirst
first
four
sites
listed
arethe
theprimary
this
thisstudy.
study.
Shackleton
et al.
al. [1990]
this paper).
paper). The
Shackletonet
[1990] is
is used
usedthroughout
throughoutthis
The
period between
between 1.2
1.2 and
and 0.7
period
0.7 Ma
Ma was
wasaatransition
transitionbetween
between
relatively smaller
ice
variability of
of the
the
relatively
smallerglacial-interglacial
glacial-interglacial
icevolume
volumevariability
Pliocene
and
early
Pleistocene
and
the
larger
ice
volume
Pliocene and early Pleistoceneand the larger ice volume
variability
that
the
The
in
variability
thatcharacterized
characterized
thelate
latePleistocene.
Pleistocene.
Theincrease
increase
in
(6180) signal
signal
the
of
ice
theamplitude
amplitude
ofthe
theglacial-interglacial
glacial-interglacial
icevolume
volume
(6•80)
was
with
wasassociated
associated
withaa change
changein
in the
thedominant
dominantperiodicity
periodicityof
of ice
ice
volume
variability
from
41
kyr
(obliquity)
prior
to
0.7
Ma
to
volumevariabilityfrom41 kyr (obliquity)priorto 0.7 Ma to100
100
kyr
Ruddiman et
etal.,
kyrafter
after0.7
0.7 Ma
Ma [Prel!,
[Prell,1984;
1984;Ruddiman
al.,1989].
1989].
Down-core
foraminiferal
abundance
changes
and
Down-coreplanktonic
planktonic
foraminiferal
abundance
changes
and
changes
in
carbon
isotope
gradients
indicate
that
changes
ininterbasin
interbasin
carbon
isotope
gradients
indicate
thatthe
the
evolution
ice
was
by
evolutionof
ofthe
thecontinental
continental
icesheet
sheetsystem
system
wasaccompanied
accompanied
by
changes
in
North
Atlantic
SSTs
and
deepwater
circulation.
changesin North Atlantic SSTs and deepwatercirculation.
keeping
et al.
keepingwith
with the
thelate
lateQuaternary
Quaternarymodel,
model,Raymo
Raymo et
al. [1990]
[1990]
found
of
with
foundthat
thatglacial
glacialsuppression
suppression
ofLNADW
LNADW was
wasassociated
associated
with
These
studies
suggest
reduced
North
Atlantic
SSTs.
reduced North Atlantic SSTs. These studies suggestthat
that
deepwater circulation
circulation may
may have
have played
played an
an important
role in
deepwater
important role
in
northern hemisphere
northern
hemispherecooling
coolingas
asreduced
reducedLNADW
LNADW production
production
must
musthave
havebeen
beencoupled
coupledwith
with reduced
reducednorthward
northwardheat
heattransport
transportin
in
the
upper
limb
of
the
North
Atlantic
therrnohaline
circulation
cell
theupperlimb of theNorthAtlanticthermohaline
circulation
cell
throughout
throughoutthe
the last
last3.2
3.2 Ma.
Ma.
The
history
of
UNADW
the past
past 1.2
my. was
The historyof UNADW over
over the
1.2 m.y.
wasstudied
studiedby
by
de
was
de Menocal
Menocal et
et al.
al. [1992].
[1992].UNADW
UNADW production
production
wasenhanced
enhanced
during
relative
as
duringglaciations
glaciations
relativeto
tointerglaciations
interglaciations
asitit was
wasduring
duringthe
the
last glaciation
last
glaciation[Boy!e
[Boyleand
andKeigwin,
Keigwin,1987].
1987].Generally,
Generally,glaciations
glaciations
of greatest
as
of
greatestLNADW
LNADW suppression
suppression
asidentified
identifiedby
byRaymo
Raytooet
et al.
al.
[1990]
[1990] were
were associated
associatedwith
with greatest
greatestrelative
relativeUNADW
UNADW
contribution
contributionto
to the
themiddepth
middepthNorth
North Atlantic,
Atlantic, suggesting
suggestingan
an outout-
of-phase
behavior between
between UNADW
UNADWand
andLNADW.
LNADW. In
of-phasebehavior
In this
this
study,
we
explore
whether
glacial-interglacial
fluctuations
study, we explore whetherglacial-interglacialfluctuationsin
in
UNADW export
export to
tropical
Atlantic
UNADW
tothe
themiddepth
middepth
tropical
Atlanticalso
als0occurred
occurred
between
2.6 and
between 2.6
and 1.2
1.2 Ma
Ma and
andwhether
whetherincreasing
increasing glacial
glacial
suppression
of LNADW
etal.,
suppression
of
LNADW since
since2.6
2.6Ma
Ma [Raymo
[Raymoet
al.,1990]
1990]was
was
643 x
643
ß
60
60
40
40
"liii'
uiJfI
•
120
2.0
x 610
849
i
502
100
1 O0
80
80
60
t•0
p
4A1
ti
ß
677
849
644x
I!!
.u.u..
N1iiI
20
20
0
: ••
40
40
Figure 1.
Figure
1. Core
Corelocations.
locations.
20
2_0
0
OPPO
El AL.:
RECORD
OF
NORTH
OPPOET
AL.'AA'3C
•13C
RECORD
OFUPPER
UPPER
NORTHATLANTIC
ATLANTICDEEP
DEEPWATER
WATER
accompanied
by
production
of
accompanied
byincreased
increased
production
of UNADW,
UNADW,as
asmight
mightbe
be
predicted
by
tendency
for
UNADW
predicted
bythe
theapparent
apparent
tendency
forthe
therelative
relative
UNADW
contribution
to
in the late
contribution
to vary
varyinversely
inverselywith
with that
thatof
of LNADW
LNADW in.the
late
Pleistocene.
We
also
discuss
long-term
trends
evident
in
Pleistocene.
Wealso
discuss
long-term
trends
evident
inthe
theö'3C
•5•3C
records.
records.
375
375
Raymo et
etal.
Raymo
al. [1989,
[1989,1990,
1990,19921.
1992]. The
Thesite
site849
849record
recordis
isfrom
fromMix
M/x
etal.
[1995].
et al. [ 1995].
Most
Most of
of the
thesite
site502
502benthic
benthicisotope
isotoperecord
recordabove
above1135
1135 m
m
(composite depth)
depth) was
was published
published by
by de
de Menocal
Menoca!et
etal.
(composite
al. [1992].
[ 1992]. A
A
few additional
additional measurements
few
measurements in
in this
this section
section have
have been
been made
made and
and
are included
included in
in this
this paper
paper (Table
(Table 2).
2). The
are
The new
newdata
datafor
for site
site502
502
were generated
generated in
were
in two
two laboratories:
laboratories:at
at the
theLamont-Doherty
Lamont-DohertyEarth
Earth
Data and
and Stratigraphy
Stratigraphy
Data
Observatory
on aa Finnigan
Observatory(LDEO)
(LDEO) on
FinniganMAT25I
MAT251 with
with aacommon
common
acid
bath
kept
at
90°C
and
atatthe
Woods
Hole
Oceanographic
acid
bath
kept
at
90øC
and
the
Woods
Hole
Oceanographic
13C
gradients
through
time,
we
To
study
changing
oceanic
To study
changing
oceanic
•513C
gradients
through
time,we
Institution (WHOE) on a Finnigan MAT252 with 70°C acid
use benthic
use
benthicforaminiferal
foraminiferalcarbon
carbonisotope
isotoperecords
recordsfrom
fromseveral
several Institution (WHOI) on a Finnigan MAT252 with 70øC acid
dropped
into
dropped
into single
singlereaction
reactionvessels.
vessels.Samples
Samplesfrom
from44
44depths
depths
We use
deep-sea
deep-seasites
sites(Table
(Table1,
1, Figure
Figure1).
1). We
usethe
thebenthic
benthic
were run
run in
both
laboratories.
The
difference
between
samples
were
in
both
laboratories.
The
difference
between
samples
foraminiferal
isotope
record
from
DSDP
site
552
in
the
middepth
foraminiferal
isotope
recordfromDSDPsite552in themiddepth
run in
in the
the two
two laboratories
laboratorieswas
was0.16
0.16+±0.18
0.18%•%(mean
(meanand
andlo)l)
North Atlantic
Atlantic to
to monitor
changes in
in the
the •5•3C
&3C value
of the
North
monitor
changes
valueof
the run
and 0.04 ±. 0.15% for 518O and 5'3C, respectively,
with
respectively,
withthe
the
nutrient-depleted, northern
northern source
source water
water end-member.
end-member. Whereas
nutrient-depleted,
Whereas and0.04+. 0.15%•for /5•80and/5•3C,
WHO!
laboratory
giving
the
more
positive
values
for
both
WHOI
laboratory
giving
the
more
positive
values
for
both
this core
this
core is
is located
locatedwithin
within the
thecore
coreof
of NADW
NADW today,
today,during
duringthe
the
oxygen and carbon. Isotope data in both labs are calibrated
last glaciation,
containing
last
glaciation,site
site552
552was
waslocated
locatedininwaters
waters
containing oxygen and carbon. Isotope data in both labs are calibrated
the use
of
through the
use of
of standards
standardsfrom
from the
the National
National Bureau
Bureau of
approximately
50%
low-ö'3C
southern
source
waters
[Oppo
and
approximately
50%low-•j•3C
southern
source
waters
[Oppo
and through
Standards (NBS-20 at LDEO and NBS-19 at WHOL), so the
Lehman, 1993].
Lehman,
1993].We
Weuse
usethe
therecord
recordfrom
fromODP
ODPsite
site849
849to
tomonitor
monitor Standards (NBS-20 at LDEO and NBS-19 at WHOI), so the
reason
unclear. Because
reasonfor
for these
thesedifferences
differencesis
is unclear.
Becausepublished
publishedvalues
values
'3C value
value of
of Pacific
Pacific Deep
Water, the
the low-•j•3C
low-13C
changes in
changes
inthe
the•5•3C
Deep
Water,
of
the
site
502
record
were
generated
at
LDEO,
for
continuity,
we
of
the
site
502
record
were
generated
at
LDEO,
for
continuity,
we
end-member
to
the
Atlantic
via
the
Southern
Ocean.
Because
the
end-member
SouthernOcean. Because
adjusted
the
WHOL
values by
by subtracting
subtracting 0.16
0.16 and
0.04
%
from
adjusted
the
WHOI
values
and
0.04
%•
from
deep
Pacific
contains
the
greatest
volume
of
the
ocean's
deep
deepPacificcontains
thegreatest
volumeof theocean's
deep
S'O and 513C respectively.
respectively.
water,
to
water,its
its&3C
•5•3Cvalue
valueis
isoften
oftenassumed
assumed
tobe
beclose
closeto
tothat
thatof
ofthe
the 15•Oand15•3C
The
The composite
compositedepth
depthmodel
modelfor
for site
site502
502 (Table
(Table2),
2), based
basedon
on
mean
here. Variations
meanocean,
ocean,and
andwe
we make
makethis
thisassumption
assumption
here.
Variationsin
in
interhole
correlations
of
sediments
from
holes
502,
502A,
502B,
interhole
correlations
of
sediments
from
holes
502,
502A,
502B,
ö'3C
by
•5•3Cat
atsite
site607,
607,in
inthe
thedeep
deepNorth
NorthAtlantic,
Atlantic,are
aredominated
dominated
by
and 502C,
502C, is
is taken
takenfrom
from W.
W. L.
L. Prell
Prell [manuscript
[manuscriptin
in preparation,
preparation,
variations in
in the
contribution
of
NADW
variations
therelative
relative
contribution
ofhigh-ö'3C
high-•Sl3C
NADWand
and and
Composite
depths
for
the
other
cores
are
from
1995].
1995].
Composite
depths
for
the
other
cores
are
from the
the
low-ö'3C
southern
source
waters
to
the
deep
Atlantic
[Raymo
et
low-•j13C
southern
source
watersto thedeepAtlantic[Raytooet
literature
cited
above
and
references
therein
[Ruddiman
et
literature
cited
above
and
references
therein
[Ruddiman
et al.,
al.,
al.,
three
we
from
al., 1990].
1990].To
Tothese
these
threerecords,
records,
weadd
addaarecord
record
fromDSDP
DSDP
1989; Raymo et al., 1989, 1990, 1992; Shackleton et al., 1990;
site 502
site
502 (Table
(Table1),
1), located
locatedon
onthe
theMono
MonoRidge
Ridgein
inthe
thewestern
western 1989; Raytooet al., 1989, 1990, 1992; Shackletonet al., 1990;
Mix
et al.,
al., 1995].
Mix
et
1995]. The
Thetimescale
timescalefor
foreach
eachcore
corewas
wasgenerated
generatedby
by
Colombian
Basin.
Because
the
Caribbean
Sea
has
an
effective
Colombian Basin. Because the Caribbean Sea has an effective
correlation
of
the
benthic
5180
record
totothe
high-resolution
correlation
of
the
benthic
/5•O
record
the
high-resolution
sill
depth
of
1800
m
[Wust,
1964],
ö'3C
values
at
this
site
should
silldepth
of1800m[Wast,
1964],
•5•3C
values
atthissiteshould
record
Previous
recordfrom
fromPacific
PacificODP
ODP site
site677,
677,using
usingthe
theorbital
orbitalchronology
chronology
reflect ö'3C
values
in
open
Atlantic.
reflect
•5•3C
values
inthe
themiddepth
middepth
open
Atlantic. Previous
constructed
by
Shack!eton
et
al.
[1990].
Both
the
constructed
by
Shackleton
et
al.
[1990].
Both
thepublished
published[de
[de
studies have shown
studies
shown that
that the
the Caribbean
Caribbean Sea
Seacontained
contained more
more
Menocal
et
al.,
19921
and
new
5180
and
S'3C
data
of
C.
Menocal
et
al.,
1992]
and
new
/5•80
and
513C
data
of
C.
UNADW
relative
to
southern
sources
during
late
Pleistocene
UNADW relative to southernsourcesduringlate Pleistocene
wue!!erstorfl from
from site
site 502
502 are
are shown
shown versus
versus age
age in
in Figure
Figure 2
2 and
wuellerstorfi
and
glaciations
than
during
interglaciations
[Boyle
and
Keigwin,
glaciations
thanduringinterglaciations
[Boyleand Keigwin,
listedin
in Table
Table 2.
2. The
Theage
agemodel
modelfor
forsite
site502
502is
isgiven
givenin
in Table
Table3.
3.
1987;
Oppo and
and Fairbanks,
Fairbanks, 1987,
de Menocal
et al.,
al., listed
1987;Oppo
1987,1990;
1990;de
Menocalet
Sedimentation
rates
vary
little
from
the
average
rate
of
Sedimentationratesvary little from the averagerate of about
about2
2
1992].
cm/kyr. With the exception of the interval between 2.1 and 1.7
All four
All
four records
records are
are based
basedprimarily
primarily on
on the
the benthic
benthic cm/kyr. With the exceptionof the interval between2.1 and 1.7
58Ø record
exhibits
very low
Ma, when
Ma,
whenthe
thesite
site502
502/5•80
record
exhibits
very
lowamplitude
amplitude
foraminiferal
species
Cibicidoides
wuellerstorfi,
aaspecies
which
foraminiferal
species
Cibicidoides
wuellerstorfi,
species
which fluctuations, correlation to other benthic isotope records was
fluctuations,correlationto other benthic isotoperecordswas
in
most
regions
appears
to
reliably
record
deepwater
ö'3C
values
inmost
regions
appears
toreliably
record
deepwater
•5•3C
values straightforward (Figure 3) and did not violate paleomagnetic
(Figure 3) and did not violate paleomagnetic
[e.g.,
Belanger et
years
of
[e.g.,Belanger
etal.,
al.,1981].
1981]. For
Forthe
thelast
last250,000
250,000
years
ofthe
thesite
site straightforward
constraints [Kent
1982;Shackleton
Shack!etonetetal.,
constraints
[Kentand
andSpariosu,
Spariosu,
1982;
al., 1990].
1990].
607
composite
record,
Ruddiman
et
al.
[1989]
constructed
a
stack
607composite
record,
Ruddiman
etal. [1989]constructed
a stack
The
average
sampling
intervals
(calculated
after
omitting
data
The
average
sampling
intervals
(calculated
after
omitting
data
which
included Uvigerina
Uvigerina data
data from
from core
whichincluded
coreV30-97
V30-97 [Mix
[Mix and
and gaps of -20 kyr or greater at sites 502 and 552) at sites 552, 502,
gaps
of
•-20
kyr
or
greater
at
sites
502
and
552)
at
sites
552,
502,
Fairbanks, 1985]
data
Fairbanks,
1985]and
andC.
C.wuellerstorfl
wuellerstorfi
datafrom
fromcore
coreCHN82-4CHN82-4607, and
6 kyr,
kyr, 66 kyr,
and 849
849 are
are approximately
approximately6
kyr, 44 kyr,
kyr, and
and44 kyr,
kyr,
24
and Boyle,
the
24 [Keigwin
[Keigwinand
Boyle,1985].
1985].We
Wehave
havenot
notremoved
removed
the 607,
respectively.
Because
of
the
large
sampling
interval
at
sites
respectively.
Because
of
the
large
sampling
interval
at
sites552
552
Uvigerina
data
since
the
main
difference
between
the
Uvigerina
Uvigerinadatasincethemaindifference
between
theUvigerina and 502 and the large gaps that occur in these two records, we
and
502
and
the
large
gaps
that
occur
in
these
two
records,
we
and
data
is
5'3C
were
andC.
C.wuellerstorfl
wuellerstorfi
data
isthat
thatthe
theUvigerina
Uvigerina
•3Cvalues
values
were focus on long-term trends present in the data.
focus
on
long-term
trends
present
in
the
data.
lower
detailed
of the
the late
late
lowerduring
duringthe
thelast
lastglaciation;
g!aciation;
detailedcomparisons
comparisons
of
Pleistocene
Caribbean
Sea
have
Pleistocene
Caribbean
Seaand
anddeep
deepNorth
NorthAtlantic
Atlanticrecords
records
have
been
of
[e.g.,
Results and
and Discussion
Discussion
beenthe
thesubject
subject
ofother
otherstudies
studies
[e.g.,Boyle
Boyleand
andKeigwin,
Keigwin,1987;
1987' Results
Oppo
and
Fairbanks,
1987,
1990;
de
Menocal
et
al.,
1992]
and
OppoandFairbanks,1987,1990;de Menocalet al., 1992]and Oxygen Isotopes
Some Uvigerina
are
are not
not the
thefocus
focusof
of this
thisstudy.
study. Some
Uvigerina values
valuesare
are Oxygen Isotopes
The site
included
in
the
site
849
record,
and
they
also
have
not
been
The
site502
502 benthic
benthicoxygen
oxygenisotope
isotoperecord
recordprovides
providesno
nonew
new
included in the site 849 record, and they also have not been
insights
beyond
those
already
gleaned
from
the
higher-resolution
removed
since
paired
C.
wuellerstorfi
and
Uvigerina
spp.
data
insights
beyond
those
already
gleaned
from
the
higher-resolution
removedsincepairedC. wuellerstorfiandUvigerinaspp.data
records (e.g.,
[Ruddiman
indicate aa constant
indicate
constantdown-core
down-core offset
offset between
between the
the two
two species
species records
(e.g.,sites
sites607,
607,677,
677,and
and849
849records
records
[Ruddimanet
et al.,
al.,
1989; Raytoo
Raymo et
et al.,
et
[Mix
etal.,
Values
of
of
spp.
are
al., 1989,
1989,1990,
1990,1992;
1992;Shack!eton
Shackleton
et al.,
al.,1990;
1990;
[Mixet
al.,1995].
1995].
Values
of5'3C
•5•3C
ofUvigerina
Uvigerina
spp.
arecorrected
corrected 1989;
Mix et
et al.,
5180
values
are
to
values
and
al., 1995]).
1995]).The
Theonly
onlysignificant
significantdifference
differencebetween
betweenthe
the
toC.
C.wuellerstorfi
wuellerstorfi
values
andC.
C.wuellerstorfi
wuellerstorfi
•5180
values
are Mix
sites
502
record
and
other
oxygen
isotope
records
that
cannot
corrected
to
Uvigerina
values
using
correction
factors
given
by
sites
502
record
and
other
oxygen
isotope
records
that
cannotbe
be
corrected
to Uvigerinavaluesusingcorrection
factorsgivenby
attributed
amplitude
attributedto
to differences
differencesin
in resolution
resolutionis
isthe
thedampened
dampened
amplitude
Shackleton
Shackleton and
and Hall
Hall [1984].
[1984]. The
The site
site 552
552 data
datahave
havebeen
been
of the
the&80
•5•80record
recordfrom
from-2.1
-2.1toto1.7
1.7Ma,
Ma,when
whenthe
thesite
site502
502record
record
published
by Shackleton
and Hall
Hall [1984]
published
by
Shackleton
and
[ 1984]and
andCurry
Curryand
andMiller
Miller of
5180
values.
We
appears
to
record
only
interglacial
(low)
[1989].
The
site
607
data
are
from
Ruddiman
et
al.
[1989]
and
torecord
onlyinterglacial
(low)fi180values.
Weknow
know
[1989]. The site607 dataare from Ruddimanet al. [1989] and appears
OPPO
DEEP WATER
WATER
OPPOET
ET AL.:
AL.:A ö'3C
•13CRECORD
RECORDOF
OFUPPER
UPPERNORTH
NORTHATLANTIC
ATLANTICDEEP
376
376
Table
Table 2.
2. Isotope
IsotopeData
Data From
From Site
Site 502
502
Core
Core
Depth,
Depth,
cm
cm
CDS,
CDS,
m
m
Table
Table 2.
2. (continued)
(continued)
ö'8O,
/5•80, ö'3C,
fi•3C,
%o
%0
Lab
Lab
%o
%0
3-1
3-1
3-1
3-1
C. wuellerstorfi
C.wuellerstorfi
lB-i
lB-i
lB-1
lB-1
18-1
lB-1
lB-i
lB-i
lB-1
lB-i
lB-1
lB-i
lB-1
lB-i
lB-1
lB-i
lB-1
lB-i
lB-1
lB-i
lB-1
lB-1
18-1
lB-1
18-1
lB-1
LB-2
lB-2
1B-2
lB-2
1B-2
lB-2
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
2B-1
28-i
2B-1
28-1
2B-1
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
28-2
2B-2
2B-2
2B-2
2B-2
2B-2
28-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
2B-2
28-3
2B-3
10.5
10.5
20.0
20.0
30.5
30.5
43.0
43.0
51.5
51.5
61.0
61.0
81.0
81.0
91.5
91.5
101.0
101.0
111.5
111.5
114.0
114.0
131.5
131.5
139.0
139.0
2.5
2.5
11.0
11.0
20.5
20.5
12.5
12.5
22.0
22.0
32.5
32.5
41.0
41.0
51.5
51.5
61.0
61.0
61.0
61.0
71.5
71.5
83.0
83.0
91.5
91.5
101.0
101.0
111.5
111.5
121.0
121.0
141.0
141.0
1.5
1.5
11.0
11.0
21.5
21.5
31.0
31.0
41.5
41.5
51.0
51.0
61.5
61.5
71.0
71.0
81.5
81.5
89.0
89.0
101.5
101.5
111.0
111.0
2.5
2.5
2B-3
2B-3
11.5
11.5
28-3
2B-3
2B-3
2B-3
2B-3
2B-3
21.0
21.0
21.0
21.0
31.5
31.5
41.0
41.0
51.5
51.5
3-1
3-1
10.5
10.5
2B-3
2B-3
3-1
3-1
2B-CC
2B-CC
61.0
61.0
20.5
20.5
6.5
6.5
2B-3
2B-3
28-3
2B-3
0.105
0.105
0.200
0.200
0.305
0.305
0.430
0.430
0.515
0.515
0.590
0.590
0.790
0.790
0.895
0.895
0.990
0.990
1.095
1.095
1.120
1.120
1.295
1.295
1.370
1.370
1.485
1.485
1.570
1.570
1.665
1.665
1.815
1.910
1.910
2.015
2.015
2.100
2.100
2.205
2.205
2.300
2.300
2.300
2.300
2.405
2.405
2.520
2.520
2.595
2.595
2.700
2.700
2.805
2.900
2.900
3.100
3.100
3.205
3.205
3.300
3.300
3.405
3.405
3.500
3.500
3.605
3.605
3.700
3.700
3.805
3.805
3.900
3.900
4.005
4.005
4.080
4.080
4.205
4.205
4.300
4.300
4.715
4.715
4.805
4.805
4.900
4.900
4.900
4.900
5.005
5.005
5.100
5.100
5.205
5.205
5.210
5.210
5.300
5.300
5.360
5.360
5.405
5.405
2.33
2.33
2.18
2.18
2.23
2.23
2.96
2.96
3.69
3.69
3.85
3.85
3.60
3.60
3.17
3.17
3.58
3.58
3.59
3.59
3.35
3.35
3.16
3.16
3.20
3.20
3.02
3.02
3.13
3.13
3.14
3.14
2.73
2.73
2.62
2.62
2.15
2.15
1.82
1.82
2.16
2.16
3.64
3.64
3.53
3.53
2.45
2.45
3.48
3.48
3.37
3.37
3.33
3.33
3.81
3.81
3.29
3.29
3.23
3.23
3.44
3.44
2.71
2.71
2.78
2.78
2.62
2.62
2.55
2.55
2.54
2.54
2.55
2.55
2.39
2.39
2.94
2.94
2.85
2.85
2.79
2.79
2.35
3.40
3.40
3.00
3.00
3.05
3.05
3.22
3.22
3.01
3.01
3.04
3.04
2.79
2.79
3.19
3.19
2.76
2.76
2.62
2.62
3.37
3.37
0.87
0.87
0.93
0.93
0.85
0.85
0.53
0.53
1.16
1.16
1.11
1.11
1.21
1.21
1.14
1.14
1.00
1.00
0.74
0.74
0.93
0.93
0.78
0.78
0.85
0.85
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEOpub
LDEO pub
LDEOpub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
WHO!
WHOI
LDEO
pub
LDEOpub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO pub
pub
LDEO
LDEO
pub
LDEO pub
0.50
0.50
WHOL
WHOI
0.63
0.63
0.94
0.94
LDEO pub
LDEOpub
LDEO
pub
LDEOpub
WHOI
WHOI
WHO!
WHOI
LDEO pub
LDEOpub
WHO!
WHOI
LDEO pub
LDEOpub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEOpub
LDEO pub
pub
LDEO
LDEO pub
LDEOpub
LDEO pub
LDEOpub
LDEO pub
LDEOpub
LDEO pub
LDEO
pub
LDEO pub
LDEOpub
LDEO
pub
LDEOpub
WHO!
WHOI
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO
pub
LDEOpub
WHO!
WHOI
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
WHO!
WHOI
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
LDEO
pub
LDEOpub
1.29
1.29
1.31
1.31
0.93
0.93
1.24
1.24
1.36
1.36
1.19
1.19
0.70
0.70
0.57
0.57
0.83
0.83
0.65
0.65
0.55
0.55
0.89
0.89
0.91
0.91
0.72
0.72
0.71
0.71
0.72
0.72
0.67
0.67
0.72
0.72
0.82
0.82
0.82
0.82
0.86
0.86
0.68
0.68
0.72
0.72
0.74
0.74
0.58
0.58
0.69
0.69
0.80
0.80
0.63
0.63
0.64
0.64
0.56
0.56
0.67
0.67
0.98
0.98
0.97
0.97
1.06
1.06
0.82
0.82
0.97
0.97
0.84
0.84
Core
Depth, CDS,
Core Depth,
CDS,
cm
m
3-!
3-1
3-1
3B-1
38-1
3B-1
3B-!
3B- 1
3-1
38-1
3B-1
30.5
30.5
49.5
49.5
70.5
70.5
90.5
90.5
5.560
5.560
6.240
6.240
21.0
21.0
109.5
31.5
6.3
10
6.310
6.3
50
6.350
6.4
15
6.415
6.5
10
6.510
2.31
2.31
3.35
3.35
2.31
2.31
2.29
2.29
2.54
2.54
2.47
2.47
3.59
3 59
2.92
292
41.0
41.0
6.560
6.560
61.0
61.0
148.5
148.5
71.5
71.5
71.5
71.5
81.0
81.0
19.5
19.5
91.5
91.5
101.0
101.0
40.5
40.5
121.0
121.0
6.710
6.710
6.740
6.740
313-2
3B-2
3B-2
3B-2
33B-2
B -2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-2
38-2
3B-2
3B-2
3B-2
3B-2
3B-2
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
3B-3
4B-!
4B-1
4B-1
4B-1
48-1
4B-1
4B- 1
4B-1
4B- 1
4B-1
4B- 11
4B4B- 1
4B-1
4B-!
4B-1
48-1
4B-1
0.82
0.82
0.80
0.80
0.79
0.79
0.76
0.76
0.75
0.75
0.68
0.68
0.75
0.75
0.88
0.88
0.78
0.78
0.49
0.49
0.75
0.75
-0.15
-0.15
0.69
0.69
0.64
0.64
0.83
0.83
0.74
0.74
0.92
0.92
6.2
15
6.215
130.5
51.5
51.5
3B-2
3B-2
%o
11.5
11.5
3-1
3B1
3B-1
3B-1
3B- 1
3-!
3-1
3B1
3B-1
3B1
3B-1
3B1
3B-1
3-2
3-2
3B1
3B-1
3B-!
3B- 1
3-2
3-2
1.5
11.0
11.0
21.5
21.5
31.0
31.0
41.5
41.5
51.0
51.0
61.5
61.5
61.5
61.5
71.0
71.0
81.5
81.5
101.0
101.0
111.5
121.5
121.5
131.0
131.0
11.5
11.5
21.0
21.0
41.0
41.0
51.5
51.5
61.0
61.0
71.9
71.9
71.5
71.5
83.0
83.0
83.0
83.0
121.0
121.0
21.5
21.5
31.5
31.5
41.0
41.0
41.0
41.0
51.5
51.5
61.0
61.0
71.5
71.5
79.0
79.0
91.5
6.6
15
6.615
6.8
15
6.815
6.8
15
6.815
6.9
10
6.910
3.21
321
7.3
731010
7.6
15
7 615
7.7
10
7 710
3.39
339
3.26
326
3.14
314
3.39
339
3.14
314
3.26
3.26
2.54
2.54
2.18
2.18
2.52
2.52
7.815
7 815
2.73
2.73
7.9
10
7.910
8.0
15
8.015
8.9
10
8.910
9.2
15
9.215
9.3 10
9.310
9.5 10
9.510
9.6 15
9.615
9.7 10
9.710
3.26
326
3.66
3 66
3.52
352
3.13
313
3.36
3 36
3.42
342
2.86
2 86
2.46
2.46
2.5!
2.51
2.57
2.57
2.56
2.56
2.88
2.88
2.84
2.84
2.62
2.62
2.66
2.66
2.69
2.69
9.815
9.815
2.71
2.71
9.8 15
9.815
2.77
2.77
9.930
9.930
2.81
2.81
9.930
9.930
2.85
2.85
6.950
6.950
7.015
7.015
7.110
7110
7.160
7 160
8.110
8.110
8.215
8.215
8.2
15
8.215
8.3
10
8.310
8.4
15
8.415
8.610
8.610
8.7
15
8.715
8.815
8.815
ö'3C,
•13C,
%o
3.63
3.63
2.65
2.65
2.63
2.63
2.55
2.55
2.57
2.57
2.44
2.44
5.750
5.750
5.960
5.960
6.160
6.160
3B3B-11
38-1
3B- 1
3B-2
3B-2
öO,
/5•80,
0.71
0.71
1.08
1.08
0.93
0.93
0.69
0.69
0.62
0.62
0.62
0.62
0.54
0.54
0.45
045
0.61
061
0.96
096
0.88
088
0.63
063
0.74
074
0.93
0.93
0.97
0.97
1.02
1 02
1.07
1 07
1.19
119
1.14
ll4
1.20
1 20
1.22
122
1.15
115
1.06
1 06
10.950
10.950
2.75
2.75
11.055
11.055
2.91
2.91
11.160
11.160
2.85
2.85
11. 265
11.265
2.69
2.69
0.94
094
0.90
0.90
0.88
0.88
0.82
0.82
0.76
0.76
0.57
0.57
0.67
0.67
0.67
0.67
0.83
0.83
0.79
0.79
1.0!
1.01
0.96
0.96
1.00
1.00
11.330
11.330
11.455
11.455
2.46
2.46
0.8!
0.81
2.41
2.41
0.81
0.81
10.3 10
10.310
3.38
3.38
10. 755
10.755
3.29
3.29
10.855
10.855
2.40
2.40
10. 950
10.950
3.14
3.14
Lab
Lab
WHOI
WHOI
LDEO
LDEO pub
pub
LDEO pub
pub
LDEO
LDEO pub
LDEO
pub
WHOI
WHOI
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
WHOI*
WH¸f
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
WHO!
WHOI
LDEO
LDEO pub
pub
WHO!
WHOI
LDEO pub
LDEO
pub
LDEO pub
pub
LDEO
LDEO
pub
LDEO pub
LDEO
LDEOpub
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
WHOL
WHOI
LDEO
LDEO pub
pub
WHO!
WHOI
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
WHOL
WHOI
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
OPPO ET AL.: A ö'3C
NORTH ATLANTIC DEEP
DEEP WATER
WATER
OPPO
•13CRECORD
RECORDOF
OF UPPER
UPPERNORTH
Table
Table 2.
2. (continued)
(continued)
Core
Depth, CDS,
Core Depth,
CDS,
m
cm
rn
4B-1
4B-1
4B-1
4B-1
4B-1
4B-1
48-1
4B-1
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
4B-2
48-2
4B-2
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4B-3
4BCC
4BCC
58-1
5B-1
58-1
5B-1
SB-i
5B-1
5B-1
5B-1
SB-i
5B-1
5B-i
5B-1
5B-i
5B-1
SB-i
5B-1
SB-i
5B-1
SB-i
5B-1
SB-i
5B-1
101.0
101.0
111.5
111.5
121.0
121.0
139.0
139.0
1.5
1.5
11.0
11.0
41.5
41.5
51.0
51.0
61.5
61.5
71.0
71.0
91.0
91.0
101.5
101.5
101.5
101.5
109.0
109.0
121.5
121.5
131.0
131.0
141.5
141.5
1.5
1.5
11.5
11.5
21.0
21.0
31.5
31.5
41.0
41.0
61.0
61.0
71.5
71.5
79.0
79.0
79.0
79.0
91.5
91.5
101.0
101.0
101.0
101.0
111.5
111.5
111.5
111.5
121.0
121.0
4.5
4.5
21.5
21.5
41.5
41.5
51.5
51.5
59.0
59.0
59.0
59.0
71.5
71.5
83.0
83.0
91.5
91.5
101.0
101.0
101.0
101.0
11.550
11.550
11.655
11.655
11.760
11.760
11.930
11.930
12.055
12.055
12.150
12.150
12.455
12.455
12.550
12.550
12.655
12.655
12.750
12.750
12.950
12.950
13.055
13.055
13.055
13.055
13.130
13.130
13.255
13.255
13.350
13.350
13.455
13.455
13.555
13.555
13.655
13.655
13.750
13.750
13.855
13.855
13.950
13.950
14.150
14.150
14.255
14.255
14.330
14.330
14.330
14.330
14.455
14.455
14.550
14.550
14.550
14.550
14.655
14.655
14.655
14.655
14.750
14.750
14.815
14.815
15.015
15.015
15.215
15.215
15.315
15.315
15.390
15.390
15.390
15.390
15.515
15.515
15.630
15.630
15.715
15.715
15.810
15.810
15.810
15.810
111.5
111.5
121.0
121.0
121.0
121.0
131.5
131.5
135.0
135.0
141.5
141.5
15.915
15.915
41.0
41.0
16.710
16.710
44.5
44.5
16.745
16.745
SB-2
5B-2
53.0
53.0
16.830
16.830
58-2
5B-2
63.5
63.5
16.935
16.935
SB-2
5B-2
71.0
71.0
17.010
17.010
SB-i
5B-1
58-1
5B-1
SB-i
5B-1
5B-i
5B-1
58-1
5B-1
5B-2
5B-2
5B-2
5B-2
16.010
16.010
16.010
16.010
16.115
16.115
16.150
16.150
16.215
16.215
377
377
Table
Table 2.
2. (continued)
(continued)
ö18O
%
2.55
2.55
3.09
3.09
3.81
3.81
3.53
3.53
3.14
3.14
3.46
3.46
3.12
3.12
3.17
3.17
2.57
2.57
2.73
2.73
2.60
2.60
2.50
2.50
2.54
2.54
2.66
2.66
2.58
2.58
3.05
3.05
2.84
2.84
2.91
2.91
2.80
2.80
2.79
2.79
2.51
2.51
2.38
2.38
3.33
3.33
3.28
3.28
3.21
3.21
3.29
3.29
2.90
2.90
2.69
2.69
2.75
2.75
2.50
2.50
2.47
2.47
2.44
2.44
2.21
2.21
2.82
2.82
2.23
2.23
2.79
2.79
3.29
3.29
3.53
3.53
2.81
2.81
2.71
2.71
2.98
2.98
2.71
2.71
2.58
2.58
2.43
2.43
2.57
2.57
2.33
2.33
2.37
2.37
2.37
2.37
1.92
1.92
3.12
3.12
2.94
2.94
2.99
2.99
3.00
3.00
2.89
2.89
ö'3C,
Lab
Lab
%o
0.65
0.65
0.66
0.66
0.94
0.94
0.79
0.79
0.72
0.72
0.57
0.57
0.73
0.73
0.78
0.78
0.88
0.88
0.95
0.95
1.02
1.02
0.96
0.96
0.78
0.78
0.83
0.83
0.69
0.69
0.80
0.80
0.91
0.91
0.92
0.92
0.96
0.96
0.88
0.88
0.75
0.75
0.77
0.77
0.56
0.56
0.68
0.68
0.31
0.31
0.28
0.28
0.65
0.65
0.80
080
0.39
039
0.64
0 64
0.34
034
071
0.71
0.47
047
0.66
0.66
0.76
0.76
0.88
0.88
0.86
0.86
0.79
0.79
0.86
0.86
0.66
0.66
0.61
0.61
0.71
0.71
0.39
0.39
0.46
0.46
0.53
0.53
0.39
0.39
0.66
0.66
0.54
0.54
0.10
0.10
0.76
0.76
0.92
0.92
0.84
0.84
0.74
0.74
0.67
0.67
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHOI
WHOI
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
Core
Core Depth,
Depth, CDS,
CDS,
cm
m
rn
58-2
5B- 2
SB-2
5B- 2
58-2
5B- 2
5B-2
5B- 2
58-3
5B- 3
SB-3
5B- 3
5B-3
5B- 3
5B-33
5B5B-3
5B-3
58-3
5
B-3
58-3
5
B- 3
5B-3
5
B-3
5B-3
5B-3
5B-3
5
B- 3
5B-3
5B- 3
5B-3
5B- 3
5B-3
5B- 3
58-3
5B- 3
5B-3
5B-3
5B-3
5B-3
SBCC
5BCC
6B-1
6B- 1
6B-i
6B- 1
6B6B-I1
611-i1
6B-
WHOI
6B-1
6
B- 1
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
6B- I1
6B6B- I1
6B-
6B -11
6B6B6
B-11
WHOI
WHOI
WHOI
WHOI
6B- I
6B-1
6B6
B- 11
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHOI
WHOI
6B- 1
6B-1
68-11
6B-
68-i1
6B6B-i1
6B-
6B-22
6B-
68-2
6B-2
68-2
6B-2
6B-2
6B-2
6B-2
6B-2
6B-2
6B- 2
68-2
6B-2
68-2
6B- 2
68-2
6B-2
68-2
6B-2
6B-2
6B-2
68-2
6B-2
6B-2
6B-2
6B-2
6B-2
6B-3
6B-3
68-3
6B-3
611-3
6B-3
611-3
6B-3
95.5
9 5.5
131.0
131.0
131.0
131.0
141.5
141.5
2.5
2.5
11.5
1 1.5
21.0
21.0
31.5
31.5
31.5
31.5
41.0
41.0
41.0
41.0
51.5
51.5
61.0
61.0
61.0
61.0
71.5
71.5
79.0
79.0
79.0
79.0
99.0
99.0
111.5
111.5
121.0
121.0
3.5
3.5
1.5
1.5
11.5
11.5
21.0
21.0
31.5
31.5
41.0
41.0
51.5
51.5
61.5
61.5
71.5
71.5
81.0
81.0
91.5
91.5
101.0
101.0
111.5
111.5
121.0
121.0
131.5
131.5
139.0
139.0
11.0
11.0
24.5
24.5
31.0
31.0
41.5
41.5
51.0
51.0
51.0
51.0
61.5
61.5
71.0
71.0
71.0
71.0
81.5
81.5
91.0
91.0
91.0
91.0
101.5
101.5
109.0
109.0
1.5
1.5
11.5
11.5
21.0
21.0
31.5
31.5
öO,
%o
0.52
0.52
0.24
0.24
0.52
0.52
0.63
0.63
0.56
O.56
0.17
0.17
0.56
0.56
0.70
0.70
0.52
0.52
0.59
0.59
0.62
0.62
17.085
17.085
2.80
2.80
17.340
17.340
17.340
17.340
17.445
17.445
3.02
3.02
17.555
17.555
2.69
2.69
2.71
2.71
2.74
2.74
17.645
17.645
2.86
2.86
i7.740
17.740
3.18
3.18
17.845
17.845
17.940
17.940
17.940
17.940
18.045
18.045
3.03
3.03
2.91
2.91
2.61
2.61
2.62
2.62
2.44
2.44
18. 140
18.140
1.98
1.98
18. 140
18.140
2.25
2.25
1.82
1.82
2.31
2.31
2.15
2.15
3.27
3.27
2.47
2.47
2.62
2.62
2.94
2.94
3.22
3.22
3.16
3.16
2.68
2.68
17.
845
17.845
18.245
18.245
18.320
18.320
18.320
18.320
18.520
18.520
18.645
18.645
18.740
18.740
18.825
18.825
19.365
19.365
19.465
19.465
19.560
19.560
19.
19.665
665
19.760
19.760
19.865
19.865
19.
960
19.960
20.065
20.065
20.
160
20.160
20.
265
20.265
20.
360
20.360
20.465
20.465
20.
560
20.560
20.
665
20.665
20.
740
20.740
20.970
20.970
21.
21 105
105
21.
21 150
150
2211.275
275
21.
350
21 350
21.350
21 350
21.475
21 475
2211.550
550
2.96
2.96
2.74
2.74
2.54
2.54
2.49
2.49
2.64
2.64
2.83
2.83
0.61
0.61
0.93
0.93
0.91
0.91
21. 750
21.750
3.00
3.00
21.750
21.750
2.39
2.39
21.
875
21.875
221.930
1.930
2.83
2.83
2.95
2.95
2.46
2.46
2.44
2.44
2.36
2.36
2.40
2.40
22.
550
22.550
22.
655
22.655
0.57
0.57
0.66
0.66
0.30
0.30
0.45
0.45
0.15
0.15
0.82
0.82
0.68
0.68
0.74
0.74
1.00
1.00
0.84
0.84
0.89
0.89
0.67
0.67
0.98
0.98
0.84
0.84
0.89
0.89
0.54
0.54
0.52
0.52
3.29
3.29
3.16
3.16
2.94
2.94
2.44
2.44
2.46
2.46
2.43
2.43
2.44
2.44
2.61
2.61
2.54
2.54
2.85
2.85
2.65
2.65
2.78
2.78
3.10
3.10
2.91
2.91
22.455
22.455
0.71
0.71
3.31
3.31
21.550
21.550
21.675
21.675
22.
3 55
22.355
'3C,
%o
2.27
2.27
0.72
0.72
0.62
0.62
0.87
0.87
0.78
0.78
0.70
0.70
0.86
0.86
0.91
0.91
0.80
0.80
0.60
0.60
0.49
0.49
0.74
0.74
0.80
0.80
0.83
0.83
0.71
0.71
0.70
0.70
0.84
0.84
0.63
0.63
0.71
0.71
0.92
0.92
0.96
0.96
0.85
0.85
1.03
1.03
Lab
WHO!
WHOI
WHOI
WHOI
WHO1
WHOI
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
WHO!
WHOI
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
pub
LDEO
LDEO pub
LDEO
pub
WHO!
WHOI
LDEO pub
pub
LDEO
LDEO
LDEO pub
pub
WHOL
WHOI
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO
pub
LDEO pub
LDEO pub
pub
LDEO
LDEO pub
LDEO
pub
LDEO pub
LDEO
pub
LDEO pub
pub
LDEO
LDEO
pub
LDEO pub
LDEO pub
pub
LDEO
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO pub
pub
LDEO
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
WHO!
WHOI
LDEO
II)EO pub
pub
LDEO
LDEO pub
pub
WHOI
WHOI
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO pub
LDEO
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
OPPO
OPPOET AL:
AL.'AA613C
•13CRECORD
RECORDOF
OFUPPER
UPPERNORTH
NORTH ATLANTIC
ATLANTIC DEEP
DEEPWATER
WATER
378
378
Table
Table 2.
2. (continued)
(continued)
Table
Table 2.
2. (continued)
(continued)
Core
CDS,
Core Depth,
Depth, CDS,
cm
m
rn
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
6B-3
41.0
41.0
51.5
51.5
61.0
61.0
71.5
71.5
78.0
78.0
91.5
91.5
6B
6B-3-3
101.0
101.0
6B-3
6B-3
6'O,
•5•80, 6'3C,
•5•3C,
%
%0
%o
%0
2.31
2.31
22.950
22.950
2.33
2.33
23 .050
23.050
2.44
2.44
0.82
0.82
0.84
0.84
0.80
0.80
0.89
0.89
23.120
23.120
2.43
2.43
0.71
0.71
23.255
23.255
2.89
2.89
23. 350
23.35O
3.23
3.23
111.5
111.5
23
.455
23.455
3.20
3.20
6B-3
6B-3
119.0
119.0
2.99
2.99
6B-3
6B-3
131.5
131.5
7B-1
7B-1
5.5
5.5
23.530
23 530
23.645
23 645
23.805
23 805
0.76
0.76
0.85
085
0.84
084
0.83
083
0.67
067
0.78
078
0.65
065
0.56
0.56
0.57
057
0.87
087
0.83
083
0.54
054
0.59
059
0.25
025
0.52
052
0.36
036
0.52
052
0.54
054
0.81
081
0.80
08O
0.50
0.50
0.45
0.45
0.80
0.80
0.54
0.54
0.60
0.60
0.82
0.82
0.96
0.96
0.79
0.79
0.46
0.46
0.92
0.92
0.67
0.67
0.76
0.76
0.78
0.78
0.75
0.75
0.77
0.77
0.75
0.75
0.58
0.58
0.61
0.61
0.72
0.72
0.77
0.77
0.58
0.58
0.86
0.86
0.76
0.76
0.79
0.79
0.38
0.38
0.76
0.76
0.80
0.80
0.63
0.63
0.57
0.57
0.84
0.84
7B- 1
7B-1
15.5
15.5
7B- 1
7B-1
23.0
23.0
23.0
23.0
2.5
2.5
11.0
11.0
31.0
31.0
31.0
31.0
41.5
41.5
51.0
51.0
61.2
61.2
71.0
71.0
71.0
71.0
91.0
91.0
7B-1
7B-1
7B-2
7B-2
78-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-2
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
713-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
7B-3
22.
750
22.750
22. 850
22.85O
2.32
2.32
23
23 .905
905
23
23 .980
980
23. 980
980
23
24.045
24.045
24.130
24.130
24. 330
24.330
24. 330
24.330
2.83
2.•3
2.64
2.64
2.90
2.90
2.87
2.87
2.94
2.94
2.19
2.19
2.45
245
2.22
222
2.15
215
24.435
24.435
24.530
24.530
2.21
221
24. 630
24.630
2.12
212
24. 730
24.730
2.96
2.96
24.730
24.730
3.06
3
06
2.30
230
24.930
24.930
2.62
262
25 .035
25.035
2.79
279
25.035
25 .035
2.51
25t
25.3 30
25.330
2.36
236
25. 3 30
25.330
2.07
207
101.5
101.5
101.5
101.5
131.0
131.0
131.0
131.0
141.5
141.5
25 .435
25.435
2.64
2
64
1.5
15
25.5535
35
25
2.93
293
11.5
115
11.5
115
25.635
25
635
3.01
301
25.635
25
635
21.0
210
21.0
210
31.5
315
41.0
410
515
51.5
61.0
610
61.0
61.0
71.5
71.5
81.0
81.0
81.0
81.0
81.0
81.0
81.0
81.0
81.0
81.0
91.5
91.5
101.0
101.0
101.0
101.0
101.0
101 0
101.00
101
101.0
101 0
111.5
111 5
25. 730
730
25
26. 330
330
26
2.96
2 96
2.65
265
3.08
3 08
2.31
231
2.35
235
2.87
2.87
2.80
2.80
2.98
2.98
2.95
2.95
2.58
2.58
2.77
2.77
2.40
2.40
2.89
2.89
26.
330
26 330
2.31
2.31
26.435
26.435
2.53
2.53
26.5 30
26.530
2.32
2.32
26. 530
26.530
2.46
2.46
26.5 30
26.530
2.27
227
26.5 30
26.530
2.19
219
2.10
210
2.29
2 29
2.15
215
2.07
2 07
2.15
215
111.5
tll
5
111.5
111 5
111.5
111 5
25 .730
25
730
25 8835
25.
35
25.930
25 930
26.035
26.035
26.
130
26.130
26.130
26 130
26.
235
26 235
26.3
30
26 330
26.
330
26 330
26.330
26
330
26. 530
26.530
26.635
26.635
26.635
26.635
26.635
26.635
26.635
26.635
Lab
Lab
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHO!
WHOI
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHOI
WHOI
WHOI
WHOI
WHOI
WHOI
LDEO
LDEO pub
pub
LDEO
LDEOpub
pub
LDEO
LDEOpub
pub
WHOI
WHOI
LDEO
LDEOpub
pub
WHOI
WHOI
WHOI
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHOI
WHOI
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHOI
WHOI
WHOI
WHOL
WHOI
WHO!
WHOI
LDEO
LDEO
WHO!
WHO1
LDEO
LDEO
LDEO
LDEO
WHO!
WHOI
WHOI
WHOI
WHOI
WHOI
WHOI
WHOI
LDEO
LDEO
LDEO
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHO!
LDEO
LDEO
WHO!
WHOI
WHOI
WHOI
WHO!
WHOI
Core
Depth, CDS,
CDS,
Core Depth,
6180,
•i•80,
cm
cm
%o
%0
7B-3
7B- 3
7B-3
7
B-3
7B-3
7
B- 3
7B-3
7B- 3
7B-3
7 B- 3
7B-3
7
B- 3
7B-3
7B-3
7B-4
7B-4
7B-4
7B-4
713-4
7B-4
713-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
713-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7B-4
7b-4
7b-4
7B-4
7 B-4
7B-4
7B-4
8B- 11
8B- 11
8B- 11
78-4
7 B-4
8B-!
8B- 1
8B- I1
7B-4
7B-4
8B-!1
8B813-!1
8B8B- 11
8B-!
8B- 1
8B-!
8B-1
121.0
121.0
121.0
121.0
!31.5
131.5
139.0
139.0
139.0
139.0
148.5
148.5
148.5
148.5
1.5
!11.5
1.5
21.0
21.0
21.0
21.0
31.5
31.5
4!.0
41.0
41.0
41. o
51.5
51.5
61.0
61.0
m
rn
27.240
27.240
2.96
2.96
0.85
0.85
LDEO
LDEO
27. 240
27.240
3.0!
3.01
0.77
0.77
WHO!
WHOI
LDEO
LDEO
LDEO
LDEO
WHO!
WHOI
LDEO
LDEO
LDEO
LDEO
WHOI
WHOI
LDEO
LDEO
WHO!
WHOI
LDEO
0.76
0.76
LDEO
LDEO
0.52
O.52
WHO!
WHOI
0.67
0.67
LDEO
LDEO
LDEO
LDEO
2.44
2.44
0.89
0.89
0.97
0.97
2.54
2.54
0.86
0.86
0.86
0.86
0.87
0.87
0.57
0.57
0.74
0.74
0.38
0.38
0.66
0.66
0.53
WHOL
0.53
WHOI
0.5!
0.51
LDEO
0.53
WHO!
0.53
WHOI
0.38
WHO!
0.38
WHOI
0.64
LDEO
0.64
0.64
WHO!
0.64
WHOI
0.24
LDEO
0.24
0.22
WHO!
0.22
WHOI
0.52
0.52
LDEO
0.83
LDEO
0.83
0.62 LDEO
LDEO
0.62
0.60
WHOL
0.60
WHOI
0.54 LDEO
0.54
0.47 LDEO
0.47
0.41 WHOI
0.41
WHOI
0.59 LDEO
0.59
0.77
0.77 LDEO
0.79 LDEO
0.79
0.78 LDEO
0.78
2.54
2.54
2.49
2.49
2.57
2.57
71.5
71.5
27. 745
27.745
2.6!
2.61
71.5
71.5
27. 745
27.745
2.56
2.56
79.0
79.0
79.0
79.0
91.5
91.5
27. 820
27.820
2.53
2.53
27.
820
27.820
2.78
2.78
27.945
27.945
2.94
2.94
3.09
3.09
2.85
2.85
2.45
2.45
2.44
2.44
2.78
2.78
2.15
2.15
3.25
3.25
91.5
91.5
27.945
27.945
!01.0
101.0
28.040
28.040
111.5
111.5
28. 145
28.145
12!.0
121.0
28.158
28.158
15.5
15.5
15.5
15.5
28.
195
28.195
28.
195
28.195
28.
255
28.255
28.
260
28.260
28.
3 55
28.355
28.
3 55
28.355
28.
375
28.375
28.455
28.455
28.455
28.455
28.
555
28.555
28.655
28.655
28.755
28.755
29.050
29.050
131.5
131.5
8B-!
8 B- 1
141.0
141.0
141.0
141.0
148.5
148.5
29.450
29.450
29.450
29.450
1.5
1.5
29.555
29.555
813-3
8B-3
WHO!
WHOI
2.53
2.53
813-!
8B- 1
88-2
8 B- 2
LDEO
LDEO
0.70
0.70
27. 345
27.345
27. 640
27.640
2.51
2.51
2.85
2.85
2.97
2.97
2.24
224
2.78
278
2.70
270
2.53
253
2.4!
241
2.32
232
2.61
261
30. 655
30.655
2.52
252
2.32
232
237
2.37
2.35
235
2.20
2 20
2.14
214
2.15
215
2.22
222
318
3.18
3.17
3.17
3.43
3.43
3.15
3.15
3.20
3.20
2.38
2.38
2.56
2.56
30. 725
30.725
2.41
2.41
29.
250
29.250
29.
355
29.355
29. 525
29.525
11.0
11
.o
29. 650
29.650
11.0
t 1.0
29.650
29.650
91.0
91.0
92.5
92.5
30.070
30.070
102.5
102.5
111.0
111 .o
121.5
12 t .5
141.5
t 4 t .5
149.5
149.5
11.5
11.5
0.72
0.72
27.440
27.440
27.440
27.440
27.545
27.545
101.0
101.0
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
LDEO
LDEO
0.79
0.79
121.0
121.0
813-2
8B-2
0.79
0.79
3.01
3.01
26.9 10
26.910
813-1
8B- 1
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
8B-2
WHO!
WHOI
WHO!
WHOI
27. 145
27.145
26.9 10
26.910
8B8B-1I
8B8B-1I
8B- I1
8B-
0.66
0.66
0.76
0.76
27.005
27.005
27.005
27.005
27.045
27.045
26. 835
26.835
27. 640
27.640
4!.5
41.5
51.5
51.5
61.5
61.5
71.5
71.5
Lab
Lab
%o
2.23
2.23
2.45
2.45
2.61
2.61
2.75
2.75
2.62
2.62
2.82
2.82
2.77
2.77
2.78
2.78
26. 730
26.730
26.730
26.730
61.0
61.0
21.5
21.5
121.0
121.0
31.5
31.5
31.5
31.5
131.5
13 t. 5
41.5
41.5
6'3C,
•13C,
30.085
30.085
30. 185
30.185
30. 270
30.270
30. 375
30.375
30.575
30.575
1.04
1.04
0.86
0.86
0.96
0.96
0.68
0.68
0.79
0.79
0.89
0.89
0.94
0.94
0.69
069
0.90
0 90
0.89
089
0.72
072
0.84
0
84
1.2!
121
0.97
0.97
0.98
0.98
0.86
0.86
LDEO
LDEO
LDEO
LDEO
WHO!
WHOI
LDEO
LDEO
LDEO
LDBO
WHOL
WHOI
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
379
379
3C RECORD
RECORD OF
OF UPPER
UPPER NORTH
NORTH ATLANTIC
ATLANTIC DEEP
DEEP WATER
OPPO
OPPOET AL.:
AL.' A 1513C
Table
Table 2.
2. (continued)
(continued)
Core
Core
Depth,
Depth,
cm
cm
8B-3
8B-3
8B-3
8B-3
8B-3
8B-3
8B-3
8B-3
9-1
9-1
8B-3
8B-3
9-1
9-1
8B-3
8B-3
8B-3
8B-3
8B-3
8B-3
9-1
9-1
8B-3
8B-3
8B-CC
8B-CC
8B-CC
8B-CC
9-1
9-1
9-2
9-2
9-2
9-2
9-2
9-2
9B-1
9B-1
9-2
9-2
9B-1
9B-1
9B-1
9B-1
98-1
9B-1
9B-1
9B-1
9B-1
9B-1
9-2
9-2
9B-1
9B-1
9B-i
9B-1
9B-1
9B-1
9B-1
9B-1
9B-2
9B-2
9-3
9-3
9B-2
9B-2
9B-2
9B-2
9-3
9-3
9B-2
9B-2
9B-2
9B-2
9-3
9-3
9-3
9-3
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-2
9B-3
9B-3
10-1
10-1
9B-3
9B-3
9B-3
9B-3
CDS,
CDS,
6O,
•180,
ö'3C,
•13C,
m
%o
%o
%o
%o
2.55
2.55
2.57
2.57
2.90
2.90
2.77
2.77
2.33
2.33
0.69
0.69
0.80
0.80
0.69
0.69
0.00
0.00
0.44
0.44
0.89
0.89
0.74
0.74
0.80
0.80
0.77
0.77
0.75
O.75
0.73
0.73
0.42
0.42
0.65
0.65
0.66
0.66
0.78
0.78
rn
30.820
30.820
30.925
30.925
31.020
31.020
31.020
31.020
31.040
31 040
31.220
31 220
31.440
31 440
31.620
31 620
31.620
31 620
31.620
31 620
31.640
31 640
31 685
107.5 31.685
107.5
3.5
31.705
31 705
3.5
12.5
31.795
12.5
31 795
124.0
31.840
124.0
31.840
32.220
32.220
14.0
14.0
32.220
32.220
14.0
14.0
32.420
34.0 32.420
34.0
21.5
32.575
32.575
21.5
54.0 32.620
32.620
54.0
31.5
32.675
32.675
31.5
51.5
32.875
32.875
51.5
32.970
61.0 32.970
61.0
32.970
61.0 32.970
61.0
33.075
33.075
71.5
71.5
33.220
114.0
33.220
114.0
101.0
33.370
33.370
101.0
33.475
111.5 33.475
111.5
33.570
33.570
121.0
121.0
33.855
149.5 33.855
149.5
33.970
33.970
11.0
11.0
34.020
44.0 34.020
44.0
34.075
21.5
34.075
21.5
34.170
31.0 34.170
31.0
34.170
64.0 34.170
64.0
34.275
41.5
34.275
41.5
34.370
51.0 34.370
510
84.0 34.370
34.370
840
84.0 34.370
34.370
840
34.475
61.5
34.475
615
71.0 34.570
34.570
710
34.570
71.0
34.570
710
34.675
34.675
81.5
815
34.675
34.675
81.5
81.5
34.770
91.0
34.770
91.0
34.875
101.5
34.875
101.5
34.970
34.970
111.0
111.0
35.005
121.5 35.005
121.5
35.100
35.100
131.0
131.0
35.195
35.195
140.5
140.5
35.285
149.5
35.285
149.5
35.345
35.345
5.5
5.5
35.440
35.440
64.0
64.0
35.450
35.450
16.0
16.0
35.450
35.450
16.0
16.0
21.0
210
31.5
315
41.0
410
41.0
410
44.0
44.0
61.0
610
84.0
84.0
101.0
101.0
101.0
101.0
101.0
101.0
104.0
104.0
Table
Table 2.
2. (continued)
(continued)
3.11
3.11
2.49
2.49
2.71
2.71
2.18
2.18
2.47
2.47
2.56
2.56
2.76
2.76
2.71
2.71
2.71
2.71
2.25
2.25
2.73
2.73
2.93
2.93
2.93
2.93
2.23
2.23
2.54
2.54
2.56
2.56
2.63
2.63
2.53
2.53
2.45
2.45
2.41
2.41
2.27
2.27
2.42
2.42
2.76
2.76
2.50
2.50
2.35
2.35
2.46
2.46
2.22
2.22
2.49
2.49
2.94
2.94
2.47
2.47
2.93
2.93
3.15
3.15
3.21
3.21
2.93
2.93
3.18
3.18
3.05
3.05
2.98
2.98
2.79
2.79
2.67
2.67
2.77
2.77
2.46
2.46
2.42
2.42
2.33
2.33
2.34
2.34
2.39
2.39
2.49
2.49
2.48
2.48
2.11
2.11
2.61
2.61
2.50
2.50
0.71
0.71
0.41
0.41
-0.05
-0.05
0.88
0.88
0.73
0.73
0.86
0.86
0.43
0.43
0.97
0.97
0.59
0.59
0.79
0.79
0.73
0.73
0.81
0.81
0.91
0.91
0.81
0.81
0.89
0.89
0.92
0.92
0.76
0.76
0.87
0.87
0.94
0.94
0.69
0.69
0.81
0.81
0.93
0.93
0.93
0.93
0.73
0.73
0.91
0.91
0.86
0.86
0.69
0.69
0.42
0.42
0.68
0.68
0.90
0.90
0.89
0.89
0.89
0.89
0.80
0.80
0.69
0.69
0.66
0.66
0.68
0.68
0.62
0.62
0.64
0.64
0.51
0.51
0.44
0.44
Lab
Lab
Core
Core
Depth,
Depth, CDS,
CDS,
cm
cm
rn
m
8O,
•180,
%o
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
WHOI
WHOI*
WHOI
WHOI
LDEO
LDEO
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOf
LDEO
WHOI
WHOI
LDEO
LDEO
LDEO
LDEO
LDEO
WHOI
WHOI
LDEO
9B-3
9B-3
31.5
31.5
35.545
35.545
3.15
3.15
10-1
10-1
10-1
10-1
84.0
84.0
84.0
84.0
51.5
51.5
61.0
61.0
61.0
61.0
5.5
5.5
5.5
5.5
124.0
124.0
124.0
124.0
8.0
8.0
144.0
144.0
144.0
144.0
21.0
21.0
335.640
5.640
2.71
2.71
2.73
2.73
2.48
2.48
2.46
2.46
2.52
2.52
2.48
2.48
2.46
2.46
10-2
10-2
10-2
10-2
14.0
14.0
14.0
14.0
336.440
6.440
336.440
6.440
I1C-2
C-2
42.0
42.0
36.540
36.540
10-2
10-2
10-2
10-2
34.0
34.0
34.0
34.0
61.0
61.0
55.0
55.0
83.0
83.0
72.0
72.0
72.0
72.0
336.640
6.640
36.
640
36.640
WHOL
WHOI
10-2
10-2
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
WHOI
WHOI
LDEO
LDEO
WHO!
WHOI
LDEO
LDEO
LDEO
WHO!
WHOI
WHO!
WHOI
LDEO
WHO!
WHOI
WHOI
WHOI
LDEO
LDEO
WHO!
WHOI
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
LDEO
WHOI
WHO!
LDEO
WHO!
WHOI
1 C-2
1C-2
9B-3
9B-3
9B-3
9B-3
913-3
9B-3
9B-CC
9B-CC
9B-CC
9B-CC
10-1
10-1
10-1
10-1
Ic-i
1C-1
10-1
10-1
10-1
10-1
!C-2
1C-2
11C-2
C-2
10-2
10-2
ic-I
1C-1
10-2
10-2
10-2
10-2
!C-2
1C-2
10-2
10-2
1C-2
1C-2
10-2
10-2
10-2
10-2
1C-3
1C-3
1C-3
1C-3
10-3
10-3
10-3
10-3
103.0
103.0
94.0
94.0
121.0
121.0
116.0
116.0
142.0
142.0
134.0
134.0
134.0
134.0
31.0
31.0
71.0
71.0
10-3
10-3
44.0
44.0
44.0
44.0
91.0
91.0
91.0
91.0
64.0
64.0
11C-3
C-3
112.0
112.0
I1C-3
C-3
10-3
10-3
10-3
10-3
10-3
10-3
112.0
112.0
IC-3
1C-3
I1C-3
C-3
2C2C-11
84.0
84.0
104.0
104.0
104.0
104.0
124.0
124.0
22.0
22.0
41.0
41.0
61.0
61.0
61.0
61.0
83.0
83.0
83.0
83.0
101.0
101.0
81.0
81.0
21.0
21.0
41.0
41.0
112A-1
2A- 1
12!.0
121.0
10-3
10-3
I1C-4
c-4
11C-4
C-4
I1C-4
C-4
11C-4
C-4
I1C-4
C-4
11C-4
C-4
1C-4
1C-4
12A-!
12A-1
2C- I
2C-1
35.640
35.640
35.745
35.745
35.
840
35.840
35.
840
35.840
35.945
35.945
35
.945
35.945
36.040
36.040
36.040
36.040
36.080
36.080
613C,
•13C,
0.69
0.69
0.31
0.31
0.33
0.33
0.51
0.51
0.47
0.47
0.50
0.50
0.60
0.60
0.46
0.46
0.36
0.36
0.37
0.37
0.52
0.52
40.490
40.490
2.02
2.02
2.43
2.43
2.47
2.47
2.45
2.45
2.45
2.45
2.14
2.14
2.39
2.39
2.56
2.56
2.34
2.34
2.19
2.19
2.07
2.07
2.07
2.07
2.29
2.29
2.46
2.46
2.18
2.18
2.56
2.56
2.17
2.17
2.07
2.07
2.20
2.20
2.27
2.27
2.08
2.08
2.15
2.15
2.47
2.47
2.22
2.22
2.17
2.17
2.23
2.23
2.02
2.02
2.83
2.83
2.16
2.16
1.74
1.74
2.58
2.58
2.17
2.17
2.10
2.10
2.02
2.02
3.17
3.17
2.45
2.45
2.18
2.18
2.57
2.57
2.47
2.47
2.46
2.46
2.42
2.42
2.35
2.35
2.24
224
2.26
2 26
40.5 10
40.510
1.77
1
77
0.35
0.35
40.710
40.710
2.20
2 20
2.04
2 04
0.58
0.58
36.
240
36.240
36.
240
36.240
36.
3 30
36.330
3 6. 730
36.730
36. 850
36.850
3 6. 950
36.950
37.020
37.020
37.020
37.020
37. 150
37.150
37. 240
37.240
3 7. 3 30
37.330
3 7.460
37.460
37.
540
37.540
37.
640
37.640
37.640
37.640
37.
760
37.760
338.160
8. 160
338.250
8. 250
338.250
8. 250
38.360
38.360
38.360
38.360
38.450
38.450
38.570
38.570
38.
570
38.570
338.650
8.650
338.850
8. 850
338.850
8. 850
39.050
39.050
39.140
39.140
39.
340
39.340
39.
540
39.540
39.
540
39.540
39.
760
39.760
39.760
39.760
39.
940
39.940
40.890
40.890
Lab
Lab
%0
%o
0.31
0.31
0.53
0.53
0.38
0.38
0.19
0.19
0.67
0.67
0.49
0.49
0.18
0.18
0.21
0.21
0.33
0.33
0.57
0.57
0.77
0.77
0.69
0.69
0.48
0.48
0.77
0.77
0.71
0.71
LDEO
LDEO
WHOL
WHOI
WHO!
WHOI
LDEO
LDEO
LDEO
LDEO
WHO!
WHOI
LDEO
LDEO
WHO!
WHOI
WHO!
WHOI
WHOI
WHOI
WHOl
WHOI
WHO!
WHOI
Wl-IOI
WHO!
WHOI
WHOI
WHO!
Wl-IOI
WHO!
Wl-tOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHOI
WHO!
W]-IOI
WHO!
WHOI
WHOl
W]-IOI
WHOL
WHOI
0.60
0.60
WHO!
WHOI
0.61
0.61
0.49
0.49
WHO!
WHOI
WHOl
WHOI
WHO!
0.65
0.65
WHOL
Wl-IOI
0.70
0.70
0.68
0.68
WHO!
WHOI
-0.04
-0.04
WHOI*
WH¸f
0.55
0.55
0.34
0.34
WHO!
WHOI
WHO!
WHOI
0.79
0.79
WHOL
WHOI
0.52
0.52
0.91
0.91
WHOI
WHOI
WHO!
WHOI
WHOl
WHOI
WHO!
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
•VHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
0.67
0.67
WHOL
WHOI
0.69
0.69
WHO!
WHOI
WHOI
WHOI
WHO!
WHOI
WHOI
WHOI
WHO!
WHOI
WHO!
WHOI
0.35
0.35
0.82
0.82
0.60
0.60
0.28
0.28
0.38
0.38
0.37
0.37
0.30
0.30
0.67
0.67
0.40
0.40
0.71
0.71
0.90
0.90
0.88
0.88
0.80
0.80
OPPO
8'3C RECORD
DEEP WATER
OPPOET AL.: A
A/513C
RECORDOF
OF UPPER
UPPERNORTH ATLANTIC DEEP
380
380
Table 2.
Table
2. (continued)
(continued)
Table
Table 2.
2. (continued)
(continued)
Core
CDS,
Core Depth,
Depth, CDS,
cm
m
cm
rn
8O,
•80,
12A-1
12A-1
121.0
121.0
40. 890
4O.89O
2.43
2.43
111B-1
lB-i
61.0
61.0
4 1.450
41
450
2.13
213
2C- 1
2C-1
143.0
143.0
41.7710
10
41
2.27
2
27
2C- 1
2C-1
143.0
143.0
41.7710
10
41
2.16
216
2C-2
2C-2
11.0
11.0
51.0
51.0
51.0
51.0
51.0
51.0
11.0
11.0
41.9
10
41 910
42 310
42.3
10
42.3
10
42 310
42.3
10
42 310
1
97
1.97
71.0
71.0
31.0
31.0
91.0
91.0
111.0
111.0
41.0
41.0
41.0
41.0
131.0
131.0
81.0
81.0
131.0
131.0
131.0
131.0
131.0
131.0
41.0
41.0
41.0
41.0
61.0
61.0
61.0
61.0
61.0
61.0
61.0
61.0
21.0
21.0
81.0
810
81.0
810
81.0
810
41.0
410
41.0
410
41.0
410
41.0
41.0
101.0
101.0
101.0
101.0
101.0
101.0
101.0
101.0
61.0
61.0
121.0
121.0
79.0
79.0
21.0
21.0
21.0
21.0
61.0
61.0
81.0
81.0
81.0
81.0
101.0
101.0
121.0
121.0
11.0
11.0
31.0
31.0
51.0
51.0
51.0
51.0
71.0
71.0
71.0
71.0
91.0
91.0
42.5
42.51010
42.
650
42.650
42.7
42.71010
42.9 10
42.910
43 .090
43.090
2.22
2 22
2.08
208
2.12
2.12
2.10
2.10
2.07
2.07
2.25
2.25
2.58
2.58
43.090
43.090
2.31
231
43.110
43.110
2.28
2
28
43 .490
43.490
2
09
2.09
43.650
43.650
2.56
256
2.27
2 27
2.19
219
2.08
208
2.02
202
2.46
2
46
2.46
2.46
2.31
2.31
2.40
2.40
2.27
2.27
2.57
2.57
2.47
2.47
2.58
2.58
2.46
2.46
2.37
2.37
2.31
2.31
2.91
2.91
2.06
2.06
2.29
2.29
2.11
2.11
2.16
2.16
2.82
2.82
2.18
2.18
2.84
2.84
2.40
2.40
2.56
2.56
2.42
2.42
2.23
223
2.25
225
2.41
241
1.94
1 94
2.31
231
3.13
313
2.91
2.91
3.06
3.06
2.64
2.64
2.47
2.47
2.58
2.58
2C-2
2C-2
2C-2
2C'-2
2C-2
2C-2
1 1B-2
11B-2
2C-2
2C-2
11B-2
llB-2
2C-2
2C-2
2C-2
2C-2
12A-3
12A-3
12A-3
12A-3
2C-2
2C-2
12A-3
12A-3
IllB-2
1B-2
1 1B-2
llB-2
1 1B-2
llB-2
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
1llB-3
IB-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
1llB-3
1B-3
11B-3
llB-3
111B-3
1B-3
11B-3
llB-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
2C-3
11B-3
llB-3
2C-3
2C-3
1llB-3
IB-3
3C3C-11
3C3C-1I
3C3C-11
3C-1
3C-1
3C3C-11
3C3C-11
3C3C-1I
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
42.450
42.450
43 .650
43.650
43.650
43.650
43.7
43.71010
43 .7 10
43.710
43.9 10
43.910
43.9 10
43.910
43 .9 10
43.910
43
.9 10
43.910
44.070
44.070
44.110
44.110
44.110
44.110
44.110
44.110
44. 260
44.260
44.
260
44.260
44.
260
44.260
44.
260
44.260
44.3
44.31010
44.3
44.31010
44.3
44.31010
44.3
44.31010
44.460
44.460
44.5
44.51010
44.
640
44.640
45
.0 10
45.010
45.0
45.01010
45.4
45.41010
45.6
45.61010
45.6
45.61010
45.8
45.81010
46.0
46.01010
46.
390
46.390
46.
590
46.590
46.790
46.790
46.790
46.790
46.990
46.990
46.990
46.990
47. 190
47.190
ö'3C,
•3C,
Lab
Lab
%o
%0
2.28
228
1.79
1
79
0.98
0.98
0.75
0.75
WHO!
WHOI
WHO!
WHOI
0.81
0.81
0.80
0.80
0.55
0.55
0.78
0.78
0.35
0.35
0.73
0.73
0.57
0.57
0.97
0.97
WHOL
WHOI
WHOI
WHOI
WHOl
WHO1
WHO!
WHOI
WHOI
WHOI*
WHO!
WHOI
WHO!
WHOI
Core
Core Depth,
Depth, CDS,
CDS,
cm
m
rn
131.0
131.0
131.0
131.0
47. 590
47.590
47.9!0
47.910
13B-1
13B-1
91.0
91.0
41.0
41.0
41.0
41.0
41.0
41.0
1 3B- 1
13B-1
I 3B- 1
13B-1
3C-2
3C-2
3C-2
3C-2
3C-2
3C-2
3C-3
3C-3
3C-3
3C-3
13B-1
13B-1
WHOL
WHOI
13B-!
13B-1
0.64
WHO!
WHOI
0.64
0.81
WHO!
WHOI
0.81
0.49
WHOl
0.49
WHOI
0.69
WHOL
WHOI
0.69
WHOI
WHOI
0.78
0.78
0.73
WHOL
WHOI
0.73
0.65
WHOI
0.65 WHO!
WHOI
0.97 WHOI
0.97
0.68 WHOL
0.68
WHOI
0.85
WHO!
WHOI
0.85
WHOL
WHOI
0.80
0.80
0.86
0.86 WHO!
WHOI
0.62 WHO!
0.62
WHOI
0.75
WHOI
0.75 WHOI
0.93 WHO!
0.93
WHOI
0.86
WHO!
0.86
WHOI
WHO!
WHOI
0.74
0.74
0.92
WHO!
WHOI
0.92
WHO!
0.47
WHOI
0.47
WHO!
WHOI
0.79
0.79
WHOI
WHOI
0.55
0.55
0.50
WHO!
WHOI
0.50
0.49
WHO!
0.49
WHOI
0.44
WHO!
0.44
WHOI
0.76
WHO!
WHOI
0.76
0.94 WHO!
WHOI
0.94
WHO!
0.72
0.72
WHOI
0.67
WHO!
WHOI
0.67
WHO!
0.78
0.78
WHOI
WHO!
0.86
WHOI
0.86
-0.07
-0.07 WHO!
WHOf
0.69 WHO!
0.69
WHOI
0.66
WHO!
0.66
WHOI
0.57 WHO!
WHOI
0.57
0.55
WHOI
0.55 WHO!
0.59 WHO!
WHOI
0.59
WHO!
0.53
0.53
WHOI
WHO!
0.74
0.74
WHOI
13
B-i
13B-1
14B-3
14B-3
14B-3
14B-3
14B-3
14B-3
14B-3
14B-3
14B-3
14B-3
0.41
0.41
!4B-3
14B-3
0.28
0.28
0.88
0.88
0.80
0.80
0.62
0.62
0.75
0.75
0.78
0.78
WHO!
WHOI
WHO!
WHOI
WHOI
WHO!
WHOI
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHO!
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-2
13B-3
13B-3
13B-3
13B-3
13B-3
13B-3
13B-3
13B-3
13B-3
13B-3
!3B-3
13B-3
14B-!
14B-1
14B-1
14B-1
14B- 1
14B-1
114B-1
4B- 1
14B-1
14B-1
!4B-!
14B-1
14B-i
14B-1
!4B-1
14B-1
1 4B- I
14B-1
14B-2
14B-2
48.!90
48.190
50. 560
50.56O
2.!7
2.17
6!.0
61.0
50. 760
50.760
83.0
83.0
101.0
101.0
121.0
121.0
131.0
131.0
11.0
11.0
31.0
31.0
50.0
50.0
73.0
73.0
91.0
91.0
91.0
91.0
91.0
91.0
111.0
111.0
131.0
131.0
22.0
22.0
41.0
41.0
61.0
61.0
83.0
83.0
101.0
101.0
121.0
121.0
22.0
22.0
22.0
22.0
22.0
22.0
41.0
41.0
61.0
61.0
101.0
101.0
141.0
141.0
50.980
50.980
52. 760
52.760
2.08
2.08
2.02
2.02
2.06
2.06
2.37
237
2.35
235
2.19
219
1.95
1
95
1.86
1
86
2.79
279
2.81
281
2.62
262
2.55
255
2.44
2.44
52. 960
52.960
53. 3 70
53.370
!41 .0
141.0
14!
141.0.0
11.0
11.0
! 4B -2
14B-2
14B-2
14B-2
i!1.0
111.0
14B-2
14B-2
111.0
111.0
!4B-2
14B-2
111.0
111.0
!4B-2
14B-2
13!.0
131.0
14B-2
14B-2
!4B-2
14B-2
14B-3
14B-3
15B-i
15B-1
15B-i
15B-1
15B-i
15B-1
15B-1
15B-1
15B-i
15B-1
%o
2.13
2.13
2.01
2.01
2.23
2.23
2.54
2.54
2.44
2.44
31.0
31.0
49.0
49.0
73.0
73.0
91.0
91.0
14B-2
14B-2
ö'80,
b•80,
21.0
21.0
41.0
41.0
6!.O
61.0
83.0
83.0
83.0
83.0
94.0
94.0
94.0
94.0
22.0
22.0
41.0
41.0
61.0
61.0
101.0
101.0
141.0
141.0
47.590
47.590
48.190
48.190
51. 160
51.160
5i.36
51.36Q
5 1.360
51.360
51. 760
51.760
5 1.960
51.960
52. 150
52.150
52.380
52.380
52. 560
52.560
52.560
52.560
52. 560
52.560
53. 5 70
53.570
53.770
53.770
53.990
53.990
54.
170
54.170
54.
370
54.370
54.670
54.670
54.670
54.670
54.
670
54.670
54.
860
54.860
55 .060
55.060
55.460
55.460
55. 860
55.860
55.860
55.860
55.860
55.860
56. 060
56.060
56.
260
56.260
56.440
56.440
56.
660
56.660
56.
840
56.840
57.040
57.040
57.040
57.040
57.040
57.040
57.240
57 240
57.
640
57 640
57.
840
57 840
58.
040
58 040
58.260
58 260
0.60
0.60
0.59
0.59
0.65
0.65
0.62
0.62
0.43
0.43
0.53
0.53
0.54
0.54
0.53
0.53
0.48
0.48
0.46
0.46
0.49
0.49
WHOL
WHOI
WHO!
WHOI
WHOl
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHOI
WHOI
WHO!
WHOI
0.36
0.36
WHO!
WHOI
0.70
0.70
WHO!
WHOI
0.61
0.61
WHO!
WHOI
0.32
0.32
WHO!
WHOI
0.67
0.67
WHOI
WHOI
0.83
0.83
WHOl
WHOI
1.98
1.98
0.74
0.74
WHOI
WHOI
2.21
2.21
2.21
2.21
2.03
2.03
2.05
2.05
2.05
2.05
2.25
2.25
3.00
3.00
2.83
2.83
2.79
2.79
2.65
2.65
2.40
2.40
1.96
1.96
1.99
1.99
0.78
0.78
0.60
0.60
0.60
0.60
0.38
0.38
0.43
0.43
2.38
2.38
2.16
2.16
2.44
2.44
2.46
2.46
1.98
1.98
2.33
2.33
2.40
2.40
2.75
2.75
2.85
2.85
2.93
2.93
2.44
2.44
1.98
1.98
1.87
1.87
2.13
2.13
2.23
2.23
5 8. 350
350
58
59 170
59.!70
2.!7
2.17
59.360
59.360
59.560
59.560
59.960
59.960
2.59
2.59
2.65
2.65
2.05
2.05
2.21
2.21
60.
3 60
60.360
Lab
Lab
%c
0.61
0.61
0.41
0.41
2.30
2.30
2.24
2.24
2.31
2.31
58.
260
58 260
5 8. 350
3 50
58
ö'3C,
0.32
0.32
0.68
0.68
0.5!
0.51
0.61
0.61
WHOL
WHOI
WHO!
WHOI
WHOl
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHOL
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
0.64
0.64
0.68
0.68
0.74
0.74
WHOL
WHOI
0.17 WHOI
WHO!
0.17
0.42 WHOI
WHO!
0.42
0.29 WHOI
0.29
WHO!
-0.02 WHO!
-0.02
WHOf
0.64 WHOI
WHO!
0.64
WHO!
0.52
0.52 WHOI
0.39
0.39 WHOI
WHOI
0.32 WHO!
0.32
WHOI
0.40 WHO!
0.40
WHOI
0.51
0.51
0.54
0.54
0.58
0.58
0.50
0.50
0.35
0.35
0.50
0.50
0.68
0.68
0.64
0.64
0.64
0.64
0.55
0.55
0.37
0.37
0.41
0.41
0.62
0.62
0.69
0.69
0.63
0.63
WHOI
WHOI
WHO!
WHOI
WHOI
WHOI
WHO!
WHOI
WHOl
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHO!
WHOI
WHOL
WHOI
WHO!
WHOI
WHO!
WHOI
WHOL
WHOI
WHO!
WHOI
WHO!
WHOI
OPPO
OPPOEl
ETAL.:
AL.:AA6'3C
•13CRECORD
RECORDOF
OFUPPER
UPPERNORTH
NORTH ATLANTIC
ATLANTIC DEEP
DEEP WATER
Table
Table 2.
2. (continued)
(continued)
Core Depth,
Depth, CDS,
CDS,
Core
m
rn
cm
cm
ö'80,
•5180, 6'3C,
•513C,
%0
%o
Lab
Lab
%o
1LB-1
11B-1
2C-1
2C-1
11B-1
llB-1
2C-1
2C-1
1IB-3
11B~3
I1B-3
11B~3
111B-3
1B-3
1IB-3
11B-3
61.0
61.0
83.0
83.0
61.0
61.0
21.0
21.0
79.0
79.0
41.0
41.0
101.0
101.0
61.0
61.0
79.0
79.0
99.5
99.5
121.0
121.0
39.540
39.540
39.760
39.760
40.910
40
910
41.050
41
050
41.090
41
090
41.250
41
250
41
310
41.310
44.460
44
46O
44.640
44.640
44.840
44.840
45.060
45.060
2.92
2.92
2.96
2.96
3.53
3.53
3.16
3.16
Core
Core data
data are
aresummarized
summarizedby
by analyzing
analyzingthe
thecovariance
covariance
-0.20
-0.20 WHOI
WHOI
-0.56
-0.56 WHO!
WHOI
-0.61
-0.61
-0.11
-0.11
WHO!
WHOI
WHOI
WHOI
3.67
3.67
-0.19
~0.19 WHO!
WHOI
0.02
WHO!
0.02
WHOI
-0.12
-0.12 WHO!
WHOI
-0.12
-0.12 WHO!
WHOI
-0.03
-0.03 WHOI
WHOI
2.96
2.96
-0.21
-0.21
3.05
3.05
-0.23
-0.23 WHOI
WHOI
3.35
3.35
3.05
3.05
2.98
2.98
3.61
3.61
sites
et al.,
al., 1990;
et al.,
sites [Raymo
[Rayrno et
1990; Mix
Mix et
al., in
in press].
press]. Time
Time series
series
analysis
of the
analysis of
the 1.2-0
1.2-0 Ma
Ma section
sectionof
of sites
sites502
502 and
and552
552 was
was
presented
by de
de Menocal
et
502,
6180
presented
by
Menocal
etal.
al.[1992].
[1992].At
Atsite
site
502,
•80 and
and
6'3C
were
in
at
cycle,
whereas
at
•513C
wereapproximately
approximately
inphase
phase
atthe
the41-kyr
41-kyr
cycle,
whereas
at
site
6'3C
lagged
minimum
6180
onesite552,
552,maximum
maximum
•5•3C
lagged
minimum
5180by
byabout
about
onequarter
quarterwavelength.
wavelength.
Uvigerina
Uvigerina spp.
spp.
1C-4
1C-4
1C-4
1C-4
2C-1
2C-1
381
381
WHO!
WHOI
between
values from
from each
each core.
core. The
betweenthe
the6180
b•80 and
and613C
b•3C values
The results
results
are
ellipses
areshown
showngraphically
graphicallyas
ascovariance
covariance
ellipses[Sokal
[Sokaland
andRohif,
Rohlf,
1969]
(Figures 6,
6, 7,
7, and
and 8).
8). The
1969] (Figures
Theprincipal
principalaxis
axisof
of each
eachellipse
ellipseis
is
the one line that describes the
the maximum
maximum dimension
dimension of variance
variance in
the
the 3180
•5•80and
and613C
fi13Cdata.
data. The minor
minoraxis
axis(not
(notshown),
shown),
perpendicular
to
perpendicular
to and
andbisecting
bisectingthe
themajor
majoraxis
axisat
at the
themean
meanof
of the
the
data,
the
by
data,represents
represents
theresidual
residualvariance
variancenot
notdescribed
described
by the
themajor
major
axis.
the
deviation
axis.The
Theellipse
ellipsecircumscribes
circumscribes
theone
onestandard
standard
deviationregion
region
about
the
mean
of
the
data.
The
more
elongated
aboutthe mean of the data. The more elongatedthe
theellipse,
ellipse,the
the
more
by
morevariance
varianceis
isdescribed
described
bythe
theprincipal
principalaxis.
axis. !t
It is
is important
important
to
could
be due
due either
to
to note
notethat
thatthe
thevariance
variancethis
thisaxis
axisrepresents
represents
couldbe
eitherto
a strong
covariance
between
strong
covariance
between6180
b•80 and
and 6'3C
b•3C or
or to
to
disproportianally
large variance
in either
or
To
disproportianally
large
variance
in
either6180
•5180
orö'3C.
•5•3C.To
The
The composite
compositedepth
depthsection
section(CDS)
(CDS) is
is taken
takenfrom
fromW.
W. B.
B. Prel
Prel distinguish between these two possibilities, we calculated the
distinguish
between
these
two
possibilities,
we
calculated
the
(manuscript in
in preparation,
preparation, 1995).
(manuscript
1995). The
Thefinal
finalcolumn
columnindicates
indicates coefficient of determination, r122, which is a measure of the
coefficient
of determination,
r122, whichis a measure
of the
where the
(LDEO,
Earth
where
thedata
datawere
weregenerated
generated
(LDEO, Lamont-Doherty
Lamont-Doherty
Earth
variance
shared
by
6180
and
6'3C
[Sokal
and Rohif,
1969].
This
variance
shared
by
•5•80
and
•5•3C
[Sokal
and
Rohlf,
1969].
This
Observatory; WHO!, Woods Hole Oceanographic Institution)
Observatory;WHOI, Woods Hole OceanographicInstitution)
and if
if they
by de
de Menocal
Menocal et
et al.
al.
and
they were
were previously
previouslypublished
publishedby
[1992].
has
from
[1992]. AA constant
constant
hasbeen
beensubtracted
subtracted
fromdata
datagenerated
generatedat
at
WHO!
WHOI as
as discussed
discussed in
in text.
text.
*Data points that were judged spurious and not included in
Data pointsthat werejudged spuriousand not includedin
the time
the
time series
seriesdisplayed
displayedin
in the
thefigures.
figures.
from
data,
fromplanktonic
planktonic(e.g.,
(e.g.,site
site502
502(W.
(W.L.
L.Prell,
Prell,unpublished
unpublished
data,
1995) and
and benthic
benthic isotope
isotope records
records from
from other
1995)
othersites
sites(Figure
(Figure3)
3) and
and
coefficient
is analogous
coefficient is
analogous and
and proportional
proportional to
to the
thesquared
squared
correlation
coefficient,
r2,
used in
in regression
analysis
with
correlation
coefficient,
r2,used
regression
analysis
withonly
only
one
aa
one random
randomvariable.
variable.Even
Evenwhen
whenthe
theprincipal
principalaxis
axisdescribes
describes
significant
percentage
of
the
variance,
the
r122
values
may
be
significant
percentage
of thevariance,
ther122values
maybe
small
small if
if most
most of
of the
the variance
variance occurs
occursin
in one
one variable
variable (i.e.,
(i.e., if
if the
the
slope
is close
slopeis
closeto
to zero).
zero). Together,
Together,these
thesequantities
quantitieswill
will help
help us
us
characterize and
characterize
and assess
assessthe
the nature
natureof
of the
therelationship
relationshipbetween
between
6180
and •5•3C
6'3C at
at the
sites. The
of
•5•80and
thedifferent
different
sites.
Theslope
slope
ofthe
theprincipal
principal
axis,
axis, the
the 95%
95% confidence
confidencelimits
limits for
for the
theslope,
slope,the
thepercent
percentof
of the
the
variance
described
by
axis
, and
the
values for
for
variance
described
bythe
theprincipal
principal
axis,
and
ther122
r122
values
from
1991;
from IRD
1RD records
records[Jansen
[Jansenand
andSjØholm,
SjOholrn,
1991;Raymo
Rayrnoet
et al.,
al.,
each
data set
each6180-6'3C
•180-•j13C
data
setare
aregiven
givenin
inTable
Table4.
4.
1986] that
that glacial
excursions
occurred,
so
values
and
1986]
glacial
excursions
occurred,
solow
low3180
•5•80
values
and
We
begin
by
discussing
two
examples:
the
6180
and
613C
data
Webeginbydiscussing
twoexamples:
the
•5•80
and
•5•3C
data
reduced
of
of
reducedamplitude
amplitude
ofthe
therecord
recordare
arenot
notdue
dueto
tothe
theabsence
absence
ofice
ice
from
sites
502
and
552
for
the
0-1
Ma
interval
(Figures
6a
from sites502 and 552 for the 0-1 Ma interval(Figures6aand
and
volume fluctuations.
The
for
volume
fluctuations.
Themost
mostlikely
likelyexplanation
explanation
for the
thereduced
reduced 6b,
6b, respectively).
respectively).The
Theslope
slopeof
of the
theprimary
primaryaxis
axisis
is positive
positivefor
for
amplitude
lived
amplitudeis
is that
thatC.
C.wuellerstorfi
wuellerstorfi
livedprimarily
primarilyduring
duringthe
the site
site 502
502 and
and negative
negativefor
for site
site552.
552. The
The covariance
covarianceellipse
ellipse
warmer,
warmer,relatively
relativelyice-free
ice-freeperiods
periodsof
of the
the2.1
2.1to
to1.7
1.7Ma
Ma interval.
interval. describing
describingthe
the site
site502
502 data
datais
ismore
moreelongated
elongatedthan
thanthe
theellipse
ellipse
This
is
with
of
Thisexplanation
explanation
isconsistent
consistent
with6180
fi•80measurements
measurements
of describing
the
The
values indicate
indicate that
that this
this is
is a
a
describing
thesite
site552
552data.
data.
Ther122
r•22values
Uvigerina
spp.
showing
more
positive,
glacial-like
values
(Table
Uvigerinaspp.showingmorepositive,glacial-likevalues(Table result
of
the
stronger
covariance
between
6180
and
6'3C
at
site
resultof thestronger
covariance
between
•5180
andb•3Catsite
2,
although
we
data
2, Figure
Figure4).
4). Thus,
Thus,
although
weinclude
include
datafrom
fromthis
thisinterval
intervalin
in
502.
502. InInaddition,
addition,the
the95%
95%confidence
confidenceinterval
intervalfor
for the
theslope
slopeis
is
most
of
and
we
that
most
ofour
ourfigures
figures
andanalyses,
analyses,
wecaution
caution
thatlike
like6180
fi•80,the
the
613C
measurements
probably
did
not
capture
the
full
•5•3Cmeasurements
probably
didnotcapture
thefull range
rangeof
of
values that
that existed
existed during
during this
this interval.
interval.
values
Isotopic Covariance
Covariance
Isotopic
Carbon isotope
Carbon
isotopedata
datafrom
fromsites
sites849,
849,552,
552,and
and502
502are
areshown
shownin
in
the site
Figure
Figure5.
5. Including
Includingthe
site 607
607 data
datarendered
renderedthe
thefigure
figure
unreadable, because
unreadable,
becausethe
the site
site502
502 and
andsite
site607
607 records
recordscontinually
continually
cross
are
crosseach
eachother.
other.Readers
Readers
arereferred
referredto
toRaymo
Raytooet
et al.
al. [1990]
[ 1990]to
to
see
of
607 data
data to
to site
site 552
552 data.
data. Because
of
the
seeaa comparison
comparison
of site
site607
Because
of the
low
low resolution of the
the site
site 502
502 record,
record, we
we forsake
forsake time
time series
series
analysis
and
instead
group
data
over
discrete
intervals
analysisand insteadgroup data over discreteintervalsto
to
determine
whether
glacial-interglacial
time
in
determine
whether
glacial-interglacial
timescale
scalevariations
variations
inthe
the
much
much smaller
smallerfor
for site
site502
502 than
thanfor
for site
site552
552 (Table
(Table 4),
4), as
aswould
would be
be
expected
expectedby
by aa glance
glanceat
at the
theraw
raw data.
data.In
In order
orderto
toevaluate
evaluatethe
the
evolving
relationship
between
6180
6'3C
at
core
site,
we
evolving
relationship
between
b•80and
and
b•3C
ateach
each
core
site,
we
show the
the covariance
ellipses and
and their
their principal
principal axes
axes for
for three
show
covarianceellipses
three
discrete
7a-7d). To
discretetime
time intervals
intervals(Figures
(Figures7a-7d).
Tomaintain
maintainclarity,
clarity,we
we
do
do not
not plot
plot the
thedata
datapoints
pointson
onthe
thefigures,
figures,but
but hope
hopethat
thatthe
the
examples provided
provided have
the readers
examples
have convinced
convincedthe
readersthat
that the
the data
dataare
are
summarized reasonably
reasonably well
well by
by the
ellipses and
and the
the
summarized
the covariance
covarianceellipses
statistics provided
statistics
providedin
in Table
Table4.
4.
The covariance
ellipses describing
describing the
the •5180
6180 and
and 3'3C
data
The
covariance
ellipses
•5•3C
data
from site
7a)
that
high
613C
values
are
from
site849
849(Figure
(Figure
7a)show
show
that
high
•5•3C
values
are
associated
with
and
associated
with intergiaciations,
interglaciations,
andlow
low values
valueswith
withglaciations.
glaciations.
Glacial-interglacial
6'3C
variability
in
Pacific
Ocean
isis
Glacial-interglacial
•5•3C
variability
inthe
thedeep
deep
Pacific
Ocean
believed to
by
in
ocean
6'3C
contribution of
of high-6'3C
UNADW to
to the
Sea
tobe
bedominated
dominated
bychanges
changes
inthe
themean
mean
ocean
•13C
contribution
high4513C
theCaribbean
Caribbean
Sea believed
occurred over
over the
the past
past 2.6
2.6m.y.
my. Results
of
analysis of
of
occurred
Results
oftime
timeseries
seriesanalysis
the higher
records
from
the
higherresolution
resolution
records
fromsites
sites607
607and
and849
849have
havealready
already
been presented,
and
and
been
presented,
andshow
showhigh
highcoherency
coherency
andan
anapproximate
approximate
180°
phase
difference
between
benthic
6180
and
'3C at
180øphase
difference
between
benthic
•5•80and6•5•3C
atboth
both
value,
as
carbon
is
between
the
value,which
whichvaries
varies
aslow-6'3C
low-•513C
carbon
istransferred
transferred
between
the
ocean
oceanand
andthe
theterrestrial
terrestrialorganic
organiccarbon
carbonreservoir
reservoir[Shackleton,
[Shackleton,
1977].
The
r122
values
of
0.23
to
0.36,
measuring
the
1977]. Ther122values
of 0.23to 0.36,measuring
theshared
shared
variance,
indicate
that
have
to
variance,
indicate
thatboth
both6180
b•80and
and6'3C
•5•3C
havecontributed
contributed
tothe
the
(o%)
08tg
1000
AGE (kyBP)
1500
2000
180 and '3C of the benthic foraminifera Cibicidoides wuellerstorfi versus age in site 502.
Selected glacial stages are labeled.
Figure 2. Values of
500
2500
-0.5
0.5
1.3
-
C
00
382
rn
zC
C
Ci
t:ii
OPPOET AL.' A •513C
RECORDOF UPPERNORTH ATLANTIC DEEPWATER
(%o)
OPPO
RECORD
OPPOET AL.:
AL' A 83C
•513C
RECORDOF
OFUPPER
UPPERNORTH
NORTH ATLANTIC
ATLANTIC DEEP
DEEPWATER
WATER
Table
Table 3.
3. Age
AgeModel
Modelfor
forSite
Site502
502
CDS,
CDS, m
m
0.20
0.20
0.59
0.59
1.095
1.095
1.66
1.66
2.01
2.01
2.205
2.205
2.30
2.30
2.805
2.805
3.205
3.205
3.60
3.60
3.90
3.90
4.30
4.30
4.715
4 715
5.405
5 405
5.85
585
6.215
6 215
6.51
651
6.71
671
77 015
015
7:31
7.31
7.615
7.615
8.015
8.015
8.61
8.61
10.31
10.31
10.755
10.755
10
855
10.855
10:95
10.95
11.5
11.5
11.76
11.76
12.15
12.15
12.80
12.80
13.55
!3.55
13.95
13.95
14.15
14.15
15.39
15.39
16.2
16.2
16.71
16.71
18.245
18.245
18.52
18.52
18.62
18.62
19.3
65
19.,365
20.265
20.265
20.855
20.855
21.55
21.55
21.675
21.675
21.93
21.93
23.35
23.35
24.435
24.435
24.73
24.73
25.33
25.33
25.635
25.635
25.93
25.93
26.235
26.235
27.145
27.145
27.945
27.945
383
383
Table 3.
Table
3. (continued)
(continued)
Age,ka
age,
ka
CDS, m
CDS,
rn
Age, ka
Age,
ka
28.755
28.755
1443
1443
18
18
29.05
29.05
1464
1464
1476
1476
4
36
36
29.555
29.555
64
64
30.185
30.185
1507
1507
116
116
31.22
31.22
1541
1541
122
!22
136
136
1558
1558
195
195
31.705
31.705
32.42
32.42
33.22
33.22
33.855
33.855
34.475
34.475
216
216
35.1
35.1
238
238
35.544
35.544
36.95
36.95
37.575
37.575
38.25
38.25
38.85
38.85
41.85
41.85
43.11
43.11
44.46
44.46
46.01
46.01
46.59
46.59
48.19
4•8.19
50.56
50.56
52.38
52.38
54,67
54.67
57.04
57.04
57,84
57.:84
58.24
58.24
59.56
59.56
60.75
60.75
151
151
182
182
250
250
270
270
298
298
310
310
330
330
342
342
352
352
385
385
404.8
404.8
415
4t5
479
479
532
532
542.5
542.5
567
567
608
608
616
616
628
628
650
650
667
667
679
679
688
688
722
722
750
750
780
780
875
875
948
948
965.3
965.3
990
990
1008
1008
1038
1038
1071
1071
1099
1099
1110
1110
1126
1126
1196
1196
1239
1239
1255
1255
1277
1277
1295
1295
1314
1314
1334
1334
1367
1367
1417
1417
1575
1575
1610
1610
1635
1635
1655
1655
1675
1675
1701
1701
1748
1748
1770
1770
1788
1788
1836
1836
1950
1950
1992
1992
2067
2067
2134
2134
2149
21,49
2188
2188
2366
236:6
2438
2438
2491
2491
2530
25.30
2555
2555
2571
2571
2594
2594
2600
2600
high covafiance
covariance (80%)
(80%) throughout
throughoutthe
thepast
past2.6
2.6m.y.
my. The
change
high
Thechange
through
time of
of the
the slope
the site
throughtime
slopeof
of the
the major
major axes
axesof
of the
.site849
849
covariance
ellipses is
increase
in
covariance
ellipses
is driven
drivenby
by the
thedisproportionate
disproportionate
increase
in
the amplitude
of the
the 6180
to the
'3C signal;
signal; .the
the
the
amplitude
of
fi•80relative
relative
to
thefi:•3C
amplitude
of
the '3C signal
signal has
has not
not changed
changed significantly
significantly despite
amplitude
of_the/5•3•C
despite
increased ice
ice volume
between
increased
volumevariability
variabilityand
andhigh
highcovariance
covafiance
between
6'8Oand8'3C.
fi•80
•andb•3C.
Approximately 80%
in
and fi•3C
6'3C at
at site
site
Approximately
80%of
of the
thevariation
variation
in518
81Soand
502 is
is explained
explained by
during
all
three
502
bythe
lheaxis
axisof
oftheir
theirc.ovariaoce
:,c,
ovariance
,dud.ng
•a!!-three
time intervals
(Table
4).
values•(0.06
0.06 to
time
imervals
,(Table
4). The
Thelow
lowr122
r•.22
,values
.to0.12)
,:0.12)
compared to
to the
the higher
co.mPared
higher values
values at
at site
site 849
849 reflect
reflect the
the
disproportionately low
low amplitude
amplitude :of
of -the
the •5-•3C
6'3C record
relative
to
dispropoaionate!y
record
relative
to
that
of
the
6180
record.
Unlike
the
principal
axes
of
the
ellipses
thatoftheõ•80record.
Unlike
:t-he
prin_cipat
axes
oftheellipses
describing the
the data
849, 607,
552, (Figures
describing
datafrom
fromsites
sites:849,
607,and
and552,
(Figures7a,
7a,7c,
7c,
and 7d),
7d), the
the principal
axes of
of the
and
principalaxes
thesite
site502
502data
dataexhibit
exhibitpositive
positive
slopes :(Figure
(Figure 7b),
aageneral
tendency
for
6'3C
slopes
7b),showing
showing
general
tendency
forhigher
higher
:8t3C
values ,to
to be
with
periods
(high
6180)
values
beassociated
associated
withcooler
cooler
periods
•(high
8180)
throughout•the
the past
past 2.6
2.6 m.y.
my. Thus
throughout
Thusfrom
from2.6
2.6to
to1.2
1.2Ma,
Ma,glacial
glacial
ö'3C
in the
tropical
Atlantic
were
than
fi•3Cvalues
values
in
themiddepth
:middepth
.tropical
Atlantic
werehigher
higherthan
interglacial
values, just
just as
interglacialvalues,
as they
theyhave
havebeen
beensince
since[Boyle
[Boyleand
and
Keigwin, 1987;
1987; Oppo
0ppo and
de .Menocal
Menocal et
et
Keigwin,
andFairbanks.,
Fairbanks,1987,
1987, 1990;
19:90;de
al., 1992].
al.,
1992].
384
384
OPPO
OPPOET AL.: A &3C
813CRECORD
RECORD OF
OF UPPER
UPPERNORTh
NORTHATLANTIC
ATLANTIC DEEP
DEEPWATER
WATER
2
502
502
0
552
552
0
00
607
607
6
849
849
8
200
200
0
400
400
600
800
1000
502
552
9D
'D
'
607
849
A)
000
doo
÷,
6'00
8'00
I
I
'
502
502
i•
552
552
0
A
00
607
607
849
849
8
2000
2000
2200
22'00
2400
24'00
2600
2600
AGE (ka)
(ka)
Figure 3.
ofofö'8O
foraminifera
from
502, 552,
552, and
and 607.
607. Records
are offset
offset for
for
Figure
3.Records
Records
5•80ininbenthic
benthic
foraminifera
fromsites
sites849,
849,502,
Records
are
clarity. Offsets
from
18Ovalues
valuesof
of Cibicidoides
Cibicidoides wuellerstorfi
wuellerstorfi are
1%,
2%,
and
for
502,
clarity.
Offsets
from5180
are0%,
0%o,
1%o,
2%o,
and3%
3%ø
forsites
sites
502,552,
552,
607,
Except
for
site
to
607, and
and849,
849, respectively.
respectively.
Except
forthe
the2.1-1.7
2.1-1.7Ma
Masection,
section,
site502
502was
waseasily
easilycorrelated
correlated
tothe
theother
otherrecords.
records.
:000
OPPO
RECORD
OF
NORTH
OPPOET
ET AL.:
AL.: A '3C
813C
RECORD
OFUPPER
UPPER
NORTHATLANTIC
ATLANTICDEEP
DEEPWATER
WATER
2
suggest
that
is
relationship
between
6180
and
suggest
thatthere
there
isno
noconsistent
consistent
relationship
between
15•80
and
4
8! 80+.64
80.s-4 C.C.wuellerstorfi
wuellerstorfi
Uvigerina spp.
80Uvigerina
spp.
18
2.5
2.5- 0
C
385
385
b•3C.
To
further,
To explore
explorethis
thissuggestion
suggestion
further,we
we examine
examinethe
thecoi'ariance
cocafiance
between
betweensite
site552
552 6180
b•80 and
andsite
site552
552613C
•5•3Cwith
with the
the mean
meanocean
ocean
6'3C
removed
(site
site
(Figure
8b).
•j•3Csignal
signal
removed
(site552
552minus
minus
site849
849ö'3C)
15•3C)
(Figure
8b).
The data
that
to
ocean
&3C
The
dataindicate
indicate
thatrelative
relative
tothe
themean
mean
ocean
•jl3Cvalue,
value,site
site
552
552has
hasalways
alwayshad
hadaatendency
tendenc.
y for
forhigher
higherglacial
glacialthan
thaninterglacial
interglacial
813C
values. The
covariances,
and
r122
values suggest
suggest that
that
15•3C
values.
Theslopes,
slopes,
covariances,
and
r•22values
this
over the
this tendency
tendencyhas
has gradually
gradually weakened
weakened over
the past
past 2.6
2.6 m.y.
m.y.
3-
(Table
(Table 4).
4).
It is
is likely
It
likely that
thattwo
two factors
factorscontribute
contributeto
to the
theweak
weakcovariance
covariance
between 6180
and •j•3C
613Cat
at552.
552. The
between
15•80and
The first
firstof
of these
theseis
isthe
theabsence
absence
of
or
relationship
between
6180
ofaa0°-phase
0ø-phase
or180°-phase
180ø-phase
relationship
between
b•80and
and6'3C,
•5•3C,
which
which exists
existsfor
for the
theother
othersites
sites[Mix
[Mix et
etal.,
al.,1995,
1995,Raymo
Raymoet
et al.,
al.,
00
3.53.5-
1990; de
de Menocal
Menocal et
et al.,
1990;
al., 1992].
1992]. The
The second,
second,which
which we
we will
will
discuss
that site
site
discussin
in more
moredetail
detaillater
laterin
in the
thepaper,
paper,is
is the
thelikelihood
likelihoodthat
4
37.5
3'.5
i
i
II
I
I
II
40.0
40.0
42.5
42.5
45.0
45.0
47.5
i
50.0
50.0
552
552 was
was located
locatedclose
closeto
to the
thesteep
steepvertical
verticalgradient
gradientbetween
between
nutrient-rich deep
deep waters
nutrient-rich
watersand
andnutrient-poor
nutrient-poorupper
upperwaters
watersduring
during
past glaciations;
past
glaciations;subtle
subtledifferences
differencesin
in surface
surfaceforcing
forcingmay
mayresult
result
in vertical
migration
of
6'3C
gradient
and
of
in
vertical
migration
ofthe
thesteep
steep
b•3C
gradient
andthe
thebathing
bathing
of
site
having
different
6'3C
values.
Which
waters
site552
552by
bywaters
waters
having
different
•j•3C
values.
Which
waters
site
of site
552
site 552
552 is
is bathed
bathedin
in depends
dependson
on the
therelative
relativelocation
locationof
site 552
to
between
the
Figure
4.
of
forfor
thethe
benthic
foraminifera
Uvigerina
withrespect
respect
tothe
theboundary
boundary
between
thehigh
highand
andlow
low6'3C
bt3C
Figure
4.Values
Values
ofö'O
15
•80
benthic
foraminifera
Uvigerina with
species
for the
water masses.
masses.
speciesand
andCibicidoides
Cibicidoideswuellerstorfi
wuellerstorfifor
the depth
depthinterval
interval water
CDS (m)
CDS
corresponding
to 2.1
2.1 to
to 1.7
Ma. AA constant
corresponding
to
1.7 Ma.
constant0.64%
0.64%øhas
hasbeen
been
added to the
the Cibicidoides
so that
that these
these values
values
added
Cibicidoideswuellerstorfi
wuellerstorfivalues
valuesso
can
and
canbe
be directly
directlycompared
comparedto
to Uvigerina
Uvigerinavalues
values[Shackleton
[Shackleton
and
Hall,
Hall, 19841.
1984]. More
Morenegative
negativeCibicidoides
Cibicidoideswuellerstorfi
wuellerstorfivalues
values
after adjustment
after
adjustment are
are consistent
consistentwith
with the
the absence
absenceof
of glacial
glacial
specimens.
specimens.
Thus
analysis indicates
indicates that
that of
of the
Thus covariance
covariance analysis
the four
four sites
sites
studied,
exhibited
studied,site
site 502
502 is
is the
theonly
onlysite
siteto
tohave
haveconsistently
consistently
exhibitedaa
general
tendency
for
glacial
than
interglacial
6'3C
values
general
tendency
forhigher
higher
glacial
than
interglacial
•j•3C
values
throughout
the
past
2.6
my.
Subtracting
the
Pacific
(site
throughoutthe past2.6 m.y. Subtractingthe Pacific (site 849)
849)
record
the site
record from
from the
site 552
552 record,
record,however,
however, reveals
reveals that
that relative
relative to
to
the
value,
North
themean
meanocean
ocean6'3C
15•3C
value,site
site552
552in
inthe
themiddepth
middepth
North
Atlantic
has also
also experienced
experienced higher
higher glacial
glacial 15•3C
6'3C values.
values. In
Atlantic
has
In the
the
sections
which
follow,
we
discuss
long-term
6'3C
trends
at
sections
whichfollow,wediscuss
long-term
•5•3C
trends
atsites
sites
The
approximately
constant
slope
of
the
principal
axes
through
The approximately
constantslopeof theprincipalaxesthrough 552 and 502 and the evolution of 6'3C gradients between the core
552and502andtheevolution
of•j•3Cgradients
between
thecore
time at
at site
site 502
502 is
is rather
rather striking.
striking. However,
time
However,if
if the
thesite
site849
849 record
record sites. We also show that the higher glacial than interglacial 6'3C
sites.
We
also
show
that
the
higher
glacial
than
interglacial
•jt3C
is
to
ocean
8'3C
signal
[Mixet
etal.,
isin
infact
factclose
close
tothe
themean
mean
ocean
•5•3C
signal
[Mix
al.,1995],
1995], values at site 502 throughout the interval studied are probably
values
at
site
502
throughout
the
interval
studied
are
probably
then
ellipses
that
site
502
versus
site
thenthe
thecovariance
covariance
ellipses
thatdescribe
describe
site
5026180
15•80
versus
site due to a greater contribution of northern source waters during
due to a greatercontributionof northernsourcewatersduring
502
are
502 minus
minussite
site849
849813C
b•3Cdata
data(813C(502-849))
(A•j•3C(502-849))
areaabetter
better glaciations.
description
of
the
circulation
imprint
on
the
502
8'3C
record.
description
of thecirculation
imprintonthe502 bt3Crecord. glaciations.
Because
the site
Because the
site 849
849 data
datahave
havenegative
negativecovariance
covarianceslopes,
slopes, Long-Term 6'3C Trends
Long-Term
b•3CTrends
subtracting
these
the
subtracting
thesedata
datafrom
fromthe
thesite
site502
502data
datasteepens
steepens
thepositive
positive
slope
axis. The
slopeof
of the
theprincipal
principalcovariance
covarianceaxis.
Theslopes
slopesof
of the
themajor
major
axes
ellipses
adjusted
for
ocean
613C
axesof
ofthe
thecovariance
covariance
ellipses
adjusted
formean
mean
ocean
•5•3C
changes
are
similar
for
1-2
Ma
and
0-1
Ma
but
significantly
changesare similar for 1-2 Ma and 0-1 Ma but significantly
different
different from
from the
the slope
slopeof
of the
thedata
datafrom
from the
the2-2.6
2-2.6 Ma
Ma interval
interval
(Figure 8a).
(Figure
8a). The
The similarity
similarity of
of the
the slopes
slopesduring
during the
the last
lasttwo
two
intervals
intervals suggests
suggeststhat
that at
at least
leastover
over the
thepast
past22 m.y.,
m.y.,increased
increased
We took
took the
the mean
meanand
andstandard
standarddeviation
deviationof the
the 6'3C
b•3Cdata
data
from
glacial
and
interglacial
periods
during
the
three
from glacial and interglacialperiodsduring the threetime
time
intervals
to
on
in
ö'3C
intervals
tofocus
focus
onlong
longterm
termtrends
trends
inthe
theaverage
average
bI3cvalues
values
at
9, Table
Table 5).
5). An
at each
eachsite
siteand
andbetween
betweensites
sites(Figure
(Figure9,
Anincrease
increase
through
time
values is
is evident
evident in
in the
through
timein
in813C
b•3Cvalues
thesite
site502
502and
and552
552
records
(Figure
9).
607
813C
values
are
during
the
records
(Figure
9).Site
Site
607
b•3C
values
arelower
lower
during
thepast
past
1
m.y.
than
they
were
earlier,
due
to
the
greater
incursion
of
1 m.y. thantheywereearlier,dueto thegreaterincursion
of lowlow8'3C
southern
source
waters
[Raymo
etal.,
•5•3C
southern
source
waters
[Raymo
et
al.,1990].
1990].
The
Possible reasons
reasons for
increase at
at both
both sites
sites 502 and
Possible
for the
the613C
bt3C increase
and
The negative
negative slopes
slopes of
of the
theprincipal
principal axes
axesof
of covariance
covariance
between
the 8180
data
552 include
include (1)
ocean
8'3C
increased,
(2)
betweenthe
bt80 and
and8'3C
15•3C
datafrom
fromsite
site849,
849,607
607and
and552
552 552
(1)the
themean
mean
ocean
b•3Cvalue
value
increased,
(2)the
thesites
sites
reflect
for
during
glacial
than
an
in
of
nutrientreflectthe
thetendency
tendency
forlower
lower8'3C
b•3Cvalues
values
during
glacial
than experienced
experienced
anincrease
increase
inthe
thecontribution
contribution
ofhigh-6'3C
high-/5•3C
nutrientinterglacial
source
waters,
and
of
waters
to
interglacialstages
stagesat
atthese
thesedeepwater
deepwatersites
sites(Figures
(Figures7a,
7a,7c,
7c,and
and depleted
depleted
source
waters,
and(3)
(3)6'3C
b•3Cvalues
values
ofsource
source
waters
to
7d). The
the sites
sites increased.
increased. A
of
records
7d).
Theprincipal
principalaxes
axesdescribe
describebetween
between75%
75% and
and 85%
85% of
of the
the
the
A comparison
comparison
ofthe
thesite
site502
502 and
and552
552 records
covariance between
between the
the fiGSO
6180 and
and b•3C
8'3C data
data from sites
sites 607 and
and to
covariance
to the
the deep
Pacific (site
(site 849)
that
deepPacific
849)record
recordsuggests
suggests
thatto
to the
theextent
extent
849,
compared
with
only
65%
of
the
data
from
site
552.
For
any
changes
849, comparedwith only 65% of the datafrom site552. For any that
thatthe
thesite
site849
849record
recordrepresents
represents
changesin
in the
themean
meanocean
ocean
given
613Cvalue,
value,the
theb•3C
6'3C increase
increase at
at site
site 502
502 or
or site
given interval,
interval, the
the slope
slopeof
of the
theprincipal
principalaxis
axis is
is less
lessat
at site
site552
552
b13C
site552
552may
maynot
notbe
be
than
shallow
attributed to an
an increase
increasein the
themean
meanocean
ocean6'3C
b•3Cvalue
valueover
overthe
the
thanat
at the
thetwo
two other
othersites.
sites.The
Thelow
lowcovariance,
covariance,
shallowslope,
slope, attributed
large 95%
interval
on
and
low
value at
at
past 2.6
9).
Uvigerina 8'3C
large
95%confidence
confidence
interval
onthe
theslopes,
slopes,
and
lowr122
r122
value
past
2.6m.y.
m.y.(Figure
(Figure
9). If
If the
thepredominantly
predominantly
Uvigerina
•5•3C
552
for
all
three
time
intervals
(Table
4)
suggest
that
the
record
from
the
ocean
6'3C
change
better
552 for all three time intervals (Table 4) suggestthat the
record
fromsite
site677
677reflects
reflects
themean
mean
ocean
b•3C
change
better
tendency for
for lower
lower glacial
than
interglacial •j•3C
6'3C was
was weaker
at than
tendency
glacial
thaninterglacial
weaker
at
than does
doesthe
thepredominantly
predominantlyC.
C. wuellerstorfi
wuellerstorfirecord
recordfrom
from site
site
552 than
the
r122
values approaching
zero
'3C increase
then all of
of the
the6b•3C
increaseat
at sites
sites552
552 and
and502
502 is
is
552
thanat
at607
607and
and849.
849.InInfact,
fact,
the
r122
values
approaching
zero 849, then
glacial-interglacial
ice
linearly coupled
coupled to
to
glacial-interglacial
ice volume
volumevariability
variabilitywas
waslinearly
an increase
increase in
in 6'3C
at
502.
an
b•3Cvariability
variability
atsite
site502.
OPPO ET AL.'
AL.: A ö'3C
RECORD
DEEP WATER
WATER
OPPO
•513C
RECORDOF
OF UPPER
UPPERNORTH ATLANTIC DEEP
386
386
I
I
•
I
I
-1
o'
'
2I
1
2•o
552
,•,•
46o ....
I
I
,•.••.•
66o .....
I
:.
8•o.......
•ooo
I
.,•,
• • •,.....
0
L)
0o
-1
'
1000
•o•
2000
2000
'
!'
'
1200
•2oo
1400
•ioo
2200
22'00'
2400
24'00
•
1600
•goo
'
1800
•sbo
2000
2000
.....2600
2600
AGE
AGE (ka)
(ka)
Figure
of
'3C
in benthic
benthic foraminifera
from
849
equatorial
Pacific),
502
Sea),
Figure5.
5. Records
Records
of15
•3Cin
foraminifera
fromsites
sites
849(deep
(deep
equatorial
Pacific),
502(Caribbean
(Caribbean
Sea),
and
and552
552 (middepth
(middepthsubpolar
subpolarNorth
NorthAtlantic).
Atlantic).
387
387
OPPO
RECORD
OPPOET
ET AL.:
AL ßA
A ?I3C
{5•3C
RECORDOF
OFUPPER
UPPERNORTH
NORTHATLANTIC
ATLANTIC DEEP
DEEPWATER
WATER
I
!
suggest
that bottom
water
values
in
Basin
are
suggest
that
bottom
water6'3C
•5•3C
values
inthe
thePanama
Panama
Basin
are
influenced
by overlying
and changes
changes in
in the
influencedby
overlying high
high productivity
productivityand
the
organic carbon
flux
and
6'3C values
values
organic
carbon
fluxto
tothe
thesediments
sediments
andthat
thatsite
site849
849/5•3C
are therefore
therefore more
more representative
representative of
of mean
mean deep
deep Pacific
Pacific values.
values. A
are
A
low-resolution benthic
benthic isotope
low-resolution
isotoperecord
recordfrom
from the
thewestern
westernPacific
Pacific
shows
a small
%) decrease
in
6'3C values
over
shows
a
small(0.1
(0.1%,,)
decrease
in/5•3C
values
overthe
thepast
past2.6
2.6
my.
[Whitman
and
Berger,
1990],
but
additional
detailed
m.y. [ Whitmanand Berger, 1990],but additionaldetailedPacific
Pacific
613C
recordsare
are needed
needed to
to confirm
confirm that
that the
the site
site 849
849 record
record is,
is, as
as
•5•3C
records
I
a. site 502
0-1Ma
1.5-
iIl
ß
In
ß
ß
ß ß ß
ß
I
ß
l-
we believe,
of
we
believe,more
morerepresentative
representative
ofthe
themean
meanocean
oceantrend.
trend.
Was the
6'3C rise
552
by
in
Was
the/5•3C
riseat
atsites
sites
552and
and502
502driven
driven
byan
anincrease
increase
in
0.5-
the
contribution
of
northern
source
waters?
therelative
relative
contribution
ofhigh-6'3C
high-/5]3C
northern
source
waters?
OI
I
a.
site 849
0-1 Ma
....................
1-2 Ma
..........
2-2.6Ma
0.5-1I
2
I
I
2.5
2.5
3
3.55
I
I
44i
4.5
i
4.5
I
I
5
6180 (%)
(%o)
2.5
L)
b.
_
site 552
0-1Ma
1.5-
-1
3.5
315
3
I
4
4.5
4.5
5
&18o (%0)
(%)
0.5I
1.5
b.
I
site 502
0-
.
-0.5
I
25
2.5
I
3
I
3.5
3.15
I
4I
I
I
4.5
4.5
5
I
I
55
5.5
6180
•518
0(%o)
(%0)
Figure
ellipses
ofofthe
6180
and
ö'3C
data
from
Figure6.
6.Covariance
Covariance
ellipses
the
•5•80
and
•5•3C
data
from
sites
sites (a)
(a) 502
502 and
and (b)
(b) 552
552 for
for the
the 0-1
0-1 Ma
Ma intervals.
intervals. The
The data
data
summarized
by the
summarized by
the variance
varianceellipses
ellipsesare
arealso
alsoshown.
shown. The
The
principal
the
principalaxis
axis of
of each
eachellipse
ellipsedescribes
describes
themaximum
maximumvariance
variance
between
6180 and
between/5180
and6'3C.
•13C. The
The minor
minoraxis
axis(not
(notshown),
shown),
perpendicular
to and
perpendicularto
and bisecting
bisectingthe
the major
major axis
axis at
at the
the mean
meanof
of the
the
data,
data, represents
representsthe
the residual
residualcovariance
covariancenot
not described
describedby
by the
the
major
the
major axis.
axis. The
Theellipse
ellipsecircumscribes
circumscribes
theone
onestandard
standarddeviation
deviation
region
the mean
region about
about the
mean of
of the
thedata.
data. The
The more
moreelongated
elongatedthe
the
ellipse,
by
ellipse,the
themore
morevariance
varianceis
isdescribed
described
bythe
theprincipal
principalaxis
axis[Sokal
[Sokal
and
andRohlf,
Rohlf,1969].
1969].
attributable
to
613C
changes
(Figure
The
attributable
tomean
meanocean
ocean
•5t3C
changes
(Figure9).
9). The
differences
between
differences
betweenthe
the677
677and
and849
849613C
•5•3Crecords
recordsare
areattributed
attributed
to
the
open
ocean
location
of
site
849
compared
to
the
location
to theopenoceanlocationof site849 compared
to thelocationof
of
677
et al.,
al., 1995].
677 in
in the
the Panama
PanamaBasin
Basin[Mix
[Mix et
1995]. Mix
Mix et
etal.
al. [1995]
[1995]
0.5-
0-1 Ma
0-
-0.5
2.5
2.5
3
3
....................
1-2 Ma
..........
2-2.6 Ma
3.5
3'.5
4
4.5
4.5
6180
• 180(%o)
(%0)
Figure
7.
Covanance
ellipses
of
the
6180 and
data
Figure7. Covariance
ellipses
of the/5180
and6'3C
•5t3C
datafrom
from
sites
sites(a)
(a) 849,
849, (b)
(b) 502,
502, (c)
(c) 607,
607, and
and(d)
(d) 552.
552. In
Ineach
eachcase,
case,the
the
major
axis is
is shown.
shown. Its
majoraxis
axisof
of the
thecovariance
covariance
axis
Itsslope
slopeand
andother
other
relevant
are
relevantstatistics
statistics
aregiven
givenin
in Table
Table4.
4.
OPPO
WATER
OPPO ET AL.:
AL.' A ö'3C
bl3CRECORD
RECORD OF
OF UPPER
UPPERNORTH ATLANTIC
ATLANTIC DEEP WATER
388
388
I
1.5
I
which
source
which was
was no
no longer
longerwithin
within the
thecore
coreof
of nutrient-depleted
nutrient-depleted
source
waters.
During
the
last
glaciation,
the
boundary
separating
highwaters. Duringthe lastglaciation,the boundaryseparating
highfrom 1ow-•13C
low-'3C waters
below
•:3C waters
watersabove
abovefrom
waters
belowwas
waslocated
locatednear
near
I
c. site 607
o-•Ma
....................
1-2 Ma
aa depth
depth of
of 2000
2000 m
m in
in the
thevicinity
vicinity of
of site
site552
552on
onthe
theRockall
Rockall
Plateau [Oppo
and Leh,nan,
Plateau
[Oppoand
Lehman,1993].
1993]. At
At2300-rn
2300-mwater
waterdepth,
depth,site
site
552
552 was
waslocated
locatedin
in waters
waterscontaining
containingapproximately
approximately50%
50% lowlow-
l-
ö'3C
source
waters.
Thus it appears
that 10w-5•3C
low-3C
5•3Csouthern
southern
source
waters.Thus
appears
that
southern
source
waters,
not
nutrient-depleted
source
southern
source
waters,
nothigh-'3C
high-/513C
nutrient-depleted
source
waters,
waters,have
haveincreasingly
increasinglypenetrated
penetratedto
tothis
thissite
siteduring
duringglaciations
glaciations
0.5-
I
1.5
I
I
a. site 502-849
_
l--'
-0.5
33
I
I
3.5
35
4
4.5
4.5
5
0
0.5-
ö18o (%o)
(%0)
M'. o..'ø'
0-1Ma
00
....................
1-2 Ma
I
In
2-2.6
Ma
d. site 552
.
1.5-
-0.5
I
3
2.5
.
3•.5
I
4
4.5
502,5180
I
b.
....................
1-2 Ma
..........
2-2.6Ma
site 552-
I
I
849
0-1 Ma
1.5-
....................
1-2 Ma
..........
2-2.6 Ma
0
3
3.5
3•.5
4z[
4•.5
5
5
1I
&180
•518
0(%o)
(%0)
(continued)
Figure
Figure 7.
7. (continued)
Available data
data suggest
Available
suggestthat
thatthe
thenorthern
northernsource
sourcecontribution
contributionto
to
site
over the
the past
past
site 552
552 has
hasbeen
beendecreasing
decreasingrather
ratherthan
thanincreasing
increasingover
0.5--
2.6
2.6
values
atatsite
2.6 my.
m.y.From
From
2.6toto1.0
1.0Ma,
Ma,ö'3C
/513C
values
site552
552were
were
generally
generallythe
the same
sameor
or higher
higherthan
thanat
atsites
sites502
502 (Figure
(Figure5)
5) and
and607
607
[Raymo
that it
it was
[Raymoer
et al.,
al., 1990],
1990], suggesting
suggestingthat
was located
locatedclose
closeto
to or
or
within
of
w•thinthe
the core
coreof
of NADW
NADW and
andthus
thusthe
thepercentage
percentage
of NADW
NADW to
to
that
did not
not change
change significantly
significantly over
over that
that interval.
interval. However,
However,
thatsite
sitedid
over
years,
'3C values
were
lower
overthe
thelast
lastmillion
million
years,/513C
values
wereoccasionally
occasionally
lower
at site
Sea,
ka,
at
site552
552 than
thanin
in the
theCaribbean
Caribbean
Sea,for
forexample
examplenear
near875
875 ka,
(Figure 5)
(Figure
5) and
andat
at other
othertimes
timesin
inthe
thepast
past150
150kyr
kyras
asidentified
identifiedwith
with
aa higher-resolution
Caribbean
Sea
higher-resolution
Caribbean
Searecord
record[Oppo
[Oppoand
andFairbanks,
Fairbanks,
1990; de
1990;
de Menocal
Menocal et
et al.,
al., 1992]. At
At these
thesetimes
timesnorthern
northernsource
source
waters
watersprobably
probablyformed
formedeither
eitherabove
aboveor
or downstream
downstreamof site
site552,
552,
3
i
3 5
I
4
I
4.5
5
552
552&80
b180
Figure
ellipses
of
18Oand
andfi13C
'3C (502
Figure8.
8.Covariance
Covariance
ellipses
of(a)
(a)site
site502
5025180
(502
minus
849)
and fi13C
ö'3C (552
(552 minus
minus 849).
849). The
The
minus
849)and
and(b)
(b)site
site552
552fi•80and
major
axis is
is shown.
majoraxis
axisof
of the
thecovariance
covarianceaxis
shown.Its
Itsslope
slopeand
andother
other
relevant
statistics are
are given
given in
The records
relevant statistics
in Table
Table 4.
4. The
recordswere
were
interpolated
at 5,000-year
and
interpolatedat
5,000-year intervals
intervalsprior
prior to
to subtraction,
subtraction,
and
sections
sectionswith
with data
datagaps
gapswere
were omitted.
omitted.
389
OPPO ET AL.'
AL.: A &3C
NORTH ATLANTIC
AThANTIC DEEP WATER
WATER
OPPO
bl3C RECORD OF UPPER NORTH
Table 4.
ofofMajor
ofofthe
Ellipses
Describing
at8o
and
813C
Data
Table
4.Slopes
Slopes
MajorAxes
Axes
theCovariance
Covariance
Ellipses
Describing
15•80
and
15•3C
Data
Site
Site
Age,
Age, Ma
Ma
Region
Region
0-1
0-1
Slope
Slope
849
849
607
6O7
607849
607-849
502
5O2
502849
5O2-849
552
552
552849
552-849
1-2
1-2
%Var
%Varr122
rl22
Pacific
-0.40 (-0.40,
-0.39) 81%
81% 0.23
Pacific
-0.40
(-0.40, -0.39)
0.23
deep
-1.15) 78%
78% 0.31
deepNorth
NorthAtlantic
Atlantic --1.17
1.17 (-1.20,
(-1.20, -1.15)
0.31
-0.91
(-0.94, -0.88) 75% 0.24
0.24
-0.91 (-0.94,-0.88)
0.23
0.24)
82%
Caribbean
(
0.22,
Caribbean
0.23 0.22,
82% 0.12
0.25
0.48
0.48 ( 0.47,
0.47, 0.50) 80%
80% 0.25
63% 0.02
0.02
North
-0.27 (-0.37,-0.18)
(-037, -0.18) 63%
North Atlantic
Atlantic
0.20 ( 0.17,
0.17, 0.23)
0.23) 71% 0.03
Slope
Slope
2-2.6
2-2.6
Slope
Slope
%Var
%Var r122
rl22
-0.74 (-0.75,
-0.73) 81%
81%
-0.74
(-0.75,-0.73)
-0.93 (-0.95,
-0.90) 75%
75%
-0.93
(-0.95,-0.90)
-0.27 (-0.33,-0.21)
(-0.33, -0.21) 65%
0.20
0.20 ( 0.18,
0.18, 0.21) 77%
78%
0.54
0.54 ( 0.54,
0.54, 0.55) 78%
(-0.27, -0.11) 66%
-0.19 (-0.27,-0.11)
0.53
0.53 ( 0.46,
0.46, 0.61) 67%
2
%Var
%Varr122
r•2
0.36
-0.87) 80%
80% 0.36
0.36 -0.89
-0.89 (-0.91,
(-0.91,-0.87)
0.36
0.24
-0.95) 84%
84% 0.47
0.24 -0.96
-0.96 (-0.98,
(-0.98,-0.95)
0.47
0.03
0.06
0.24
0.01
0.01
0.09
-0.59
0.22
0.22
1.27
1.27
-0.32
-0.32
0.71
0.71
(-0.66,-0.52)
(-0.66,-0.52) 68%
68% 0.11
0.11
(( 0.18,
0.18, 0.25)
0.25) 78% 0.07
0.07
(1.19,
( 1.19,1.36)
1.36) 76%
76% 0.25
0.25
(-0.43,
-0.22) 65%
(-0.43,-0.22)
65% 0.03
( 0.64,
0.64, 0.79)
0.79) 70% 0.14
0.14
95%
in parentheses.
parentheses. %Var
for
95% confidence
confidenceinterval
intervalfor
for the
theslopes
slopesare
are given
givenin
%Varis
isthe
thepercent
percentvariance
varianceaccounted
accounted
forby
by the
theprincipal
principalaxis,
axis,
and
isthe
thecoefficient
coefficient of
of determination.
determination.
andr122
r•22is
as
and
proportion
of
asclimate
climatedeteriorated,
deteriorated,
andan
anincreasing
increasing
proportion
ofnorthern
northern
component
water
cannot
account
for
rise
component
water
cannot
account
forthe
theö'3C
15•3C
riseatatthe
thesite.
site.
To evaluate
whether
the
13Cincrease
increasethrough
through time
time at
at site
site 502
502
To
evaluate
whether
the/5•3C
was
was due to increase
increase in
in the
the contribution
contribution of northern
northern source
source waters
waters
to
evolution of
of the
of
to the
thesite,
site,we
we should
shouldexamine
examinethe
theevolution
thepercentage
percentage
of
UNADW
at
502
(%UNADW502)
relative
to
southern
source
UNADW at 502 (%UNADW502) relative to southernsource
waters,
calculated
using
ö13C
records from
from cores
cores located
located in
in the
waters,
calculated
using
15•3C
records
the
core
core of
of the
the northern
northern and
and southern
southern end-member
end-member water
water masses
masses
[e.g.,
1987; Raymo
et al.,
[e.g., Oppo
Oppo and
and Fairbanks,
Fairbanks, 1987;
Raymo et
al., 1990].
1.5
IFFERG ACIAL
a.
Convincing
records
with
Convincingresults
resultsrequire
requirehigh-resolution
high-resolution
records
withexcellent
excellent
correlation
between them.
them. At
are the
the
correlationbetween
At present,
present,sites
sites552
552 and
and849
849 are
best
best available
available northern
northernand
andsouthern
southernsource
sourceend-member
end-membercores,
cores,
respectively,
above,
respectively,although
althoughas
as we
we have
havediscussed
discussed
above,site
site552
552 has
has
probably
been
influenced
by
southern
source
waters
over
the
probablybeeninfluencedby southern
sourcewatersoverthepast
past
11 m.y.,
m.y., making
making it
it aa less
lessthan
thanideal
idealend-member
end-membercore.
core.When
Whenthe
the
location
location of
of site
site552
552 contains
containssome
somesouthern
southernsource
sourcewaters,
waters,we
we
underestimate
the proportion
of UNADW
at 502.
502. In
underestimate
the
proportionof
UNADW at
Inaddition,
addition,aa
core
corefrom
fromUpper
UpperCircumpolar
CircumpolarDeep
DeepWater
Water would
wouldhave
havebeen
beenaa
much
than site
site 849,
is located
in the
much better
better end-member
end-member than
849, which
which is
located in
the
Pacific
an
record
from
South
PacificOcean.
Ocean.Although
Although
anisotope
isotope
record
frommiddepth
middepth
South
Atlantic
Atlantic site
site 704
704 is
is available,
available, the
the site
site lies
lies close
close to
to the
the core
core of
of
NADW,
13C data
data from that
NADW, and
andbenthic
benthicforaminiferal
foraminiferal15•3C
thatsite
site
ItTERGLA•AL
indicate
indicate that
that it
it too
toohas
hasbeen
beeninfluenced
influencedby
by variable
variableinput
inputof
of
NADW
Hodell and
NADW and
and southern
southernocean
oceanwater
water [Hodell,
[Hodell, 1993;
1993; Hodell
and
0.505
T
T
Venz, 1992].
between
Venz,
1992]. Finally,
Finally,precise
precisecorrelation
correlation
betweensites
sites849,
849,552,
552,
and 502
502 is difficult
difficult due to the
the low
low resolution
resolution of the site 552
552 and
502
of
502 records.
records.Despite
Despitethe
theshortcomings
shortcomings
ofthe
theavailable
availabledata
datasets,
sets,
T
o-
dramatic
changes, ifif they
be evident
dramatic changes,
they occurred,
occurred,should
should be
evident in
in aa
-05
-0.5 502
502
552
552
607
15
1.5
b.
bo
GLACIAL
GLACIAL
£
849
849
%UNADW502
record.
%UNADW502record.
The
relative to
to deep
deep Pacific
Pacific water,
The%UNADW502,
%UNADW5o2, relative
water,is
is estimated
estimated
by
the
at
by interpolating
interpolating
thesite
site552,
552,502,
502,and
and849
849records
records
atequal
equaltime
time
intervals
and
calculating
%UNADW502
as
follows:
intervalsandcalculating%UNADW502asfollows:
T
1
677
677
I
T
I
T
g
0.5
o.s,
0
0
0
Values exceeding
exceeding 100%
were assigned
assigned a value
value of
of 100%.
100%. Values
Values
100% were
Values
of %UNADW502
for the
the 22 -- 11 Ma
of
%UNADW5o2for
Ma interval
intervalare
arenot
notcalculated,
calculated,
because the
compromised
due to
to the
the bias
bias
because
theresults
resultsmay
maybe
beseriously
seriously
compromised
due
toward
interglacial
ö'3C
values
at
to 1.7
Ma and
and
toward
interglacial
15•3C
values
atsite
site502
502from
from2.0
2.0to
1.7Ma
T
0
£
-05
- 813C849
%UNADWSI2
-_________
%UNADW502
= 8'3C5o2
•13C5ø2613C849
xl00%.
b'3C552
- !113C849
613C552
613C849
x100%.
I
because
the
contains
aagap
because
thesite
site552
552record
record
contains
gapfrom
fromapproximately
approximately
1.62
to
1.32
Ma.
The
results
are
plotted
against
ö'80 for
1.62to 1.32Ma. Theresults
areplotted
against
15•80
forthe
the2.62.6AGE
22 Ma
Ma interval
Ma interval
on Figure
Figure 10.
AGE (myr
(myrBP)
BP)
intervaland
andthe
the1-0
1-0Ma
intervalon
10. ItIt is
isnot
notclear
clear
from Figure
Figure 10
10 whether
whetheror
or not
notthe
theresults
resultsfrom
fromthe
thetwo
twointervals
intervals
Figure 9.
ö'3C
data
from
sites
849,
and from
Figure
9.Mean
Mean
b•3C
data
from
sites
849,552,
552,607,
607,502,
502,and
whether
the
%UNADW502
has
677 for
and
for
differ,so
sototoevaluate
evaluate
whether
the
%UNADW502
haschanged
changed
677
for (a)
(a) interglaciations
interglaciations
and(b)
(b)glaciations
glaciations
fortime
timeintervals
intervals differ,
or
we
corresponding to
to the
the ellipses
ellipses shown
in Figure
Figure 7.
7. The
ö'3C
duringglaciations
glaciations
or interglaciations,
interglaciations,
wedivide
dividethe
thedata
datafor
for each
each
corresponding
shown
in
Themean
mean
b•3C during
data
are given
given in
in Table
Table 5.
5. Mean
time
into two
two sets,
sets, one
one corresponding
corresponding to
to 15•80
8'O data
points
data and
and one
one standard
standarddeviation
deviation are
Mean
timeinterval
interval
into
data
points
values
of the
the 6'O
range
for
interval
valuesfor
for sites
sites607
607and
and502
502are
areoffset
offseton
onthe
thetime
timeaxis
axisfor
forclarity.
clarity. that
thatare
areabove
abovethe
themidpoint
midpoint
of
15•80
range
forthat
that
interval
0
05
1
1.5
2
2.5
390
390
OPPO
RECORD OF
OF UPPER
UPPER NORTH
NORTh ATLANTIC
OPPOET AL.:
AL.' A 613C
•13CRECORD
ATLANTIC DEEP
DEEPWATER
WATER
Table
Deviation
of
ö'3C During
Table5.
5.Mean
Mean±+11Standard
Standard
Deviation
of/5•3C
During
Interval
Indicated
Interval Indicated
Age, Ma
Ma
Age,
G
G
II
G-I
G-I
Site
Site 552
552
0-1
0-1
1-2
1- 2
2 - 2.6
2.6
0.98 ±+ 0.30(8
1)
0.30(81)
0.96
0.96 ±
+ 0.19(43)
0.19(43)
0.71
0.71 ±
+ 0.28(28)
0.28(28)
1.03
± 0.35(72)
1.03 +
0.35(72)
1.03 +± 0.25(61)
0.25(61)
1.03
0.86
(67)
0.86 ±+_0.23
0.23(67)
interglacial
ö'3C values
values have
at
9,
interglacial
fi•3C
haveincreased
increased
atsite
site502
502(Figure
(Figure
9,
-0.05
-0.05
-0.07
-0.15
-0.15
Table 5),
%UNADW5Ø2
Table
5), but
butthe
the
%UNADW502during
duringinterglaciations
interglaciationshas
has
remained approximately
approximately constant
constant (Table
(Table 6).
6). Therefore
the
remained
Therefore
the6'3C
rise
riseat
at site
site502
502 cannot
cannotbe
beattributed
attributedentirely
entirelyto
to an
anincrease
increasein
in the
the
%UNADW502.
%UNADW502.
0.09
0.09
0.02
0.02
0.09
0.09
rise
in
value
rise at
at sites
sites502
502 and
and552
552 was
wasdue
dueto
toan
anincrease
increase
inthe
the&'3C
fi•3Cvalue
of North Atlantic
Atlantic surface
surfacesource
sourcewaters.
waters. The
The613C
fi•3C record
recordof
Site
Site 502
502
00-- 11
11--2"
2*
22 -2.6
- 2.6
0.83 ±+ 0.23(107)
0.72
± 0.17(76)
0.72+0.17(76)
0.66
0.66 ±
+ 0.14(18)
0.14(18)
0.74
1(56)
0.74 ±+ 0.2
0.21(56)
0.70
± 0.20(121)
0.70+0.20(121)
0.57
0.57 ±
+ 0.15(41)
0.15(41)
Finally,
the
possibility,
that
Finally,we
weevaluate
evaluate
theremaining
remaining
possibility,
thatthe
the8'3C
fi•3C
Site 607
Site
607
00- 11
1-2
1-2
2 - 2.6
2-
0.10 +± 0.49(110)
0.49(110)
0.10
0.67 ±0.39(111)
0.67+0.39(111)
0.47 +0.29(39)
± 0.29(39)
0.67
0.67 ±
+ 0.40(118)
0.40(118)
0.96±0.19(114)
0.96+0.19(114)
0.87± 0.21(115)
0.87+0.21(115)
-0.57
-0.57
-0.29
-0.29
-0.40
-0.40
Site 849
849
Site
0 - 11
01-2
1
-2
2-2.6
2- 2.6
-0.30 ±
+ 0.23(137)
-0.29
±0.19(151)
-0.29 +0.19(151)
-0.30
±0.33(57)
-0.30+0.33(57)
-0.07 ±
+ 0.23(128)
0.23(128)
-0.03
±0.20(126)
-0.03 +0.20(126)
-0.01 ±
0.18(64)
+0.18(64)
risen
(from about
about 80
80 to
risenduring
duringglaciations
glaciations(from
to 90%).
90%). Although
Althoughaa
Student
and Rohlf
the
Studentt-test
t-test[Sokal
[Sokaland
Rohlf,19691
1969]indicates
indicates
theglacial
glacialmeans
means
of
of the
the two
two intervals
intervalsare
are different
different at
at the
thegreater
greaterthan
than95%
95%
confidence
interval,
that
records
confidence
interval,we
we suggest
suggest
thathigher
higherresolution
resolution
recordsare
are
needed to
needed
to confirm
confirm the
the increase
increasein
inglacial
glacial%UNADW
%UNADW to
to the
the
middepth
middepthtropical
tropicalAtlantic.
Atlantic. In
In any
any case,
case,both
bothglacial
glacialand
and
-0.23
-0.23
-0.26
-0.26
-0.27
Neogloboquadrina pachyderma
(sinistral)
from
Neogloboquadrina
pachyderma
(sinistral)
fromNorwegian
NorwegianSea
Sea
site
site 644
644 (Figure
(Figure 1),
1), which
which has
hasaa gap
gapbetween
between2.6
2.6 and
and1.5
1.5 Ma,
Ma,
100%
lOO%
C
4.
' .t .I.
4.
S
4.
80% -80%
4.
ö'4
60%60% -
-0.54±0.21(188)
-0.54 +0.21(188) -0.36±0.29(147)
-0.36 +0.29(147)
1 --22
1
2 - 2.6
-0.60 ±
+ 0.19(169) -0.43
-0.43 ±
+ 0.24(184)
0.24(184)
-0.76 ±+0.18(33)
0.18(33)
-0.61 ±+0.22(158)
0.22(158)
-0.18
-0.18
-0.17
-0.17
-0.15
-0.15
1 -2*
2"
2 - 2.6
1
1.07
± 0.23
1.07 +
0.23
0.95
± 0.22
0.95+0.22
0.90
0.90 ±
+ 0.22
0.22
0.77
0.77 ±
+ 0.22
0.22
0.72
± 0.18
0.72+0.18
0.59
0.59 ±
+ 0.22
0.22
0.30
0.30
0.23
0.23
0.31
Site
Site 552
552 - 849
849
0 - 1
0-1
1-2
1- 2
2 - 2.6
40%40% -
4.
1.
1.
10 +± 0.21
0.21
1.10
1.06±0.24
1.06 + 0.24
0.86
0.86 ±
+ 0.22
0.22
4.
4..
4.
1.0 Ma
Ma to
to present
present
1.0
0%
0%
100%
100%
IS 41.. IS4.
0.11
0.18
0.18
0.21
Glacial
(G)
(I)
were
selected
on the
the basis
basis
Glacial
(G)and
andinterglacial
interglacial
(I)points
points
were
selected
on
on
6'3C
associated
with
ontheir
their6180
•j180values:
values:
•3C values
values
associated
with6180
•80 values
values
greater than the midpoint of the 8180 range for that interval were
considered
"glacial",
and
having
lower
6180
were
considered
"glacial",
andpoints
points
having
lower
•80 values
values
were
considered 'interglacial". Number of measurements used for
each average is incuded in parentheses. For the 502 - 849 and
each
average
isincuded
inparentheses.
Forthe502- 849and
552
both
were
at 5-kyr
5-kyr
552 -- 849
849differences,
differences,
bothrecords
records
wereinterpolated
interpolated
at
intervals
prior
to
the
analysis,
and
the
8180
record
of
Site
intervals
priortotheanalysis,
andthe/5•80
record
ofSite849
849was
was
used
to
glacial
from
813C
values. G
used
toseparate
separate
glacial
frominterglacial
interglacial
fi•3Cvalues.
G-- II isisthe
the
difference
points.
differencebetween
betweenglacial
glacialand
andinterglacial
interglacial
points.
Results from
may
biased due
due to
to the
the absence
absence of
of
*Results
fromthis
thisinterval
interval
maybe
bebiased
glacial
C.
wuellerstorfi
at
502
from
2.01.7
m.y.
BP.
glacialC. wuellerstorfiat 502 from2.0 - 1.7 m.y. BP.
4.
4.
be
1.21
± 0.27
1.21 +
0.27
1.24
± 0.23
1.24 +
0.23
1.07
± 0.27
1.07 +
0.27
4.
$
4.
20%-20%
Site
Site 502
502 - 849
849
0-1
0 - 1
4.
.4..'
Site
677
Site 677
0-1
0- 1
-
4.
80%-80%
60%60% -
greater
than
the
midpoint
of
the
•5•80
range
for
that
interval
were 40% considered
"interglacial".
Number
ofmeasurements
used
for
(glacial points)
points) and
to
that
(glacial
andone
onecorresponding
corresponding
to8180
•80 values
values
thatare
are
below
points). The
below that
that midpoint
midpoint (interglacial
(interglacial points).
The mean
meanand
andone
one
standard
deviation
value
are given
given in
in Table
Table
standard
deviation
valuefor
forthe
the%UNADW502
%UNADW502are
66 for
for glacial
glacialand
andinterglacial
interglacialperiods
periodsfor
for the
thetwo
twotime
timeintervals.
intervals.
The
suggest
that
the
%UNADW5Ø2
The calculations
calculations
suggest
that
the
%UNADW502has
hasremained
remained
approximately
constant (-70%)
(-70%) during
approximatelyconstant
duringinterglaciations
interglaciationsbut
but has
has
4.
40% -
4.
20%20% 0%
0%
2.6
2.6 to 2.0
2.0 Ma
Ma
•
•
•
•
•
2.75
2.75
3.25
3.25
3.75
3.75
4.25
4.25
4.75
4.75
849 ö180
849
/5180
Site 849
6180 versus
percentage
of
for
Figure
Figure10.
10. Site
849/5•80
versus
percentage
ofUNADW
UNADWfor
site
relative to
to sites
site502
502(%UNADW502)
(%UNADW5o2)relative
sites849
849 and
and552,
552,calculated
calculated
as
%UNADW502
Xx
asfollows:
follows:
%UNADW5o
2==(6'3C28'3C849)/(8'3Cs52-813CM9)
(•j13C502_•I3c849)/(•jI3c552-•j13C849)
100%.
100%. The
Therecords
recordswere
wereinterpolated
interpolatedatat5,000-year
5,000-yearintervals
intervals
prior
and
prior to
to subtraction,
subtraction,
andsections
sectionswith
withdata
datagaps
gapswere
wereomitted.
omitted.
Values
Valuesgreater
greaterthan
than100%
100%were
wereset
setto
to100%.
100%.
OPPO ET
El AL.:
813C RECORD
ATLANTIC DEEP
DEEP WATER
OPPO
AL.:AA/513C
RECORDOF
OF UPPER
UPPERNORTH ATLANTIC
Table
Deviation
Table 6.
6. Mean
Meanand
andStandard
Standard
Deviationfor
forInterglacial
Interglacialand
and
Glacial
of
GlacialPercentage
Percentage
of UNADW
UNADW for
forSite
Site502
502
(%UNADW502)
forthe
the2.6
2.6--22and
and 11--00Ma
MaTime
lime Intervals
(%UNADW502)
for
Intervals
Mean
Mean ±
+ Standard
Standard Deviation
Deviation
Interglacial
Interglacial
Glacial
1-OMa
1
- 0 Ma
2.6-2Ma
2.6
- 2 Ma
67±+ 17
67
17
70±21
70 + 21
89 +
± 24
78 ±
+ 21
391
the
6'3C
gradient.
An
nutrient
inventory
theAtlantic-Pacific
Atlantic-Pacific
•5•3C
gradient.
Anoceanic
oceanic
nutrient
inventory
increase,
increase, without
without an
an associated
associatedRedfield
Redfield ratio
ratio carbon
carbon increase,
increase,
may
the
Atlantic
813C
values
and
mayhave
havecaused
caused
thehigher
higher
Atlantic
•5•3C
values
andincreased
increased
6'3C
gradient.
For
assuming
that
the
Atlantic•5•3C
gradient.
Forexample,
example,
assuming
that
theNorth
North
Atlantic-
Pacific
(from
% toto1.2
Pacific(552-849)
(552-849)8'3C
•j13Cincrease
increase
(from 11%0
1.2%o)
%0)was
was
proportional
to
the
increase
in
the
6'3C
gradient
between
nutrientproportional
totheincrease
intheb•3Cgradient
between
nutrientfree
free surface
surface water
water and
and deep
deepPacific
Pacific waters,
waters, then
then the
the latter
latter
gradient
by
gradientincreased
increased
by 20
20 %
% or
or 0.35
0.35 %,
%0,from
from1.65
1.65%
%02.6
2.6m.y.
m.y.ago
ago
to
increase
ininproductivity
to 2.0
2.0 %
%0today.
today.The
Theresulting
resulting
increase
productivitywould
would
have
6'3C
values
to
in
waters
and
havecaused
caused
b•3C
values
toincrease
increase
innutrient-poor
nutrient-poor
waters
and
to
in
deep
However,
aa0.35%
6'3C
todecrease
decrease
innutrient-rich
nutrient-rich
deepwaters.
waters.
However,
0.35%0
•5•3C
rise
waters
with
risein
in nutrient-poor
nutrient-poor
waterswould
wouldbe
beassociated
associated
withonly
onlyaasmall
small
Glacial and
points
were
separated
based
on
Glacial
andinterglacial
interglacial
points
were
separated
based
on618O
5180
8'3C
drop
in
the
greater
volume
of
nutrient-rich
waters
if
mean
b•3C
drop
in
the
greater
volume
of
nutrient-rich
waters
if
mean
values greater
values:
%UNADW
associated
with
values:
%UNADWvalues
values
associated
with3180
•5180
values
greater
ocean
oceanvalues
valuesremained
remainedapproximately
approximatelyconstant.
constant. For
For example,
example,
than
the
midpoint
of
the
8180
range
for
that
interval
were
thanthemidpoint
ofthe•5•80
range
forthatinterval
were
assuming
and
assumingthat
thatthe
thevolume
volumeratio
ratioof
of nutrient-poor
nutrient-poor
andnutrient-rich
nutrient-rich
values
were
considered
'glacial," and
having
lower 6180
considered
"glacial,"
andpoints
points
having
lower
•5•80
values
were waters
was
Pacific
deepwater
6'3C
values
would
drop
waters
was1:3,
1:3,then
then
Pacific
deepwater
b•3C
values
would
drop
considered
"interglacial."
Values
greater
than
100%
were
set
by
%o totobalance
aaO.35%o
considered
"interglacial."
Valuesgreaterthan100%weresetto
to
by only
only-0.1
-0.1%0
balance
0.35%0increase
increasein
in nutrient-poor
nutrient-poor
100%.
waters.
100%.
Records of
waters. Records
of surface-dwelling
surface-dwellingplanktonic
planktonicforaminifera
foraminifera
from
the
western
tropical
Pacific,
however,
do
aa613C
fromthewestern
tropical
Pacific,
however,
donot
notexhibit
exhibit
b•3C
increase
[Schmidt
et
al.,
1990;
Whitman
and
Berger,
1990]
as
increase
[Schmidt
et
al.,
1990;
Whitman
and
Berger,
1990]
as
exhibits aa •513C
6'3C increase
increase of
of up
up to
to 1%o
l% over
exhibits
overthe
thepast
past1.5
1.5m.y.
m.y. would be predicted from this scenario.
would
be
predicted
from
this
scenario.
[Jansen
et
record
of
[Jansen
etal.,
al.,1988].
1988]. The
The6'3C
•513C
record
ofN.
N.pachyderma
pachyderrna If the Atlantic-Pacific (552-849) 6'3C gradient increased due
theAtlantic-Pacific
(552-849)•5•3C
gradient
increased
due
(sinistral),
from site
(sinistral),from
site643,
643, also
alsoin
in the
theNorwegian
NorwegianSea
Sea(Figure
(Figure1),
1),
to
to an
an increase
increase in
in whole
whole ocean
ocean nutrient
nutrient and
and carbon
carbon content
content
exhibits
an
increase
over
the
past
1
my.,
although
it
is
somewhat
exhibitsan increaseoverthe past1 m.y., althoughit is somewhat supplied with the Redfield ratio of organic matter, then, because
suppliedwith the Redfield ratio of organicmatter,then,because
smaller
than at
at site
site 644
644 [Jansets,
[Jansen, et
et al.,
the
smallerthan
al., 1988].
1988]. By
Bycontrast,
contrast,
the
organic
matter
has
the
ocean
6'3C
value
organic
matter
haslow
low813C
b•3Cvalues,
values,
themean
mean
ocean
b•3C
value
613C record
record of
bulloides
from
North
•5•3C
of Globigerina
Globigerina
bulloides
fromsubpolar
subpolar
North should
also
decrease,
unlike
the
observations
at
site
849.
Mean
should also decrease, unlike the observations at site 849. Mean
Atlantic site
site 610
610 (Figure
(Figure 1)
a 0.5%ø
0.5% decrease
2.6 to
to
Atlantic
1) shows
showsa
decreasefrom
from 2.6
ocean
ocean values
values would
would also decrease if there
there was
was an
an increase
increase in
in the
the
0.7
data,
Late Pleistocene
0.7 Ma
Ma (E.
(E. Jansen,
Jansen,unpublished
unpublished
data,1994).
1994). Late
Pleistocene weathering of organic matter relative to that of carbonate. If lowweathering
of
organic
matter
relative
to
that
of
carbonate.
If
low8'3C values
values of
of N.
(sinistral
and
at
•5•3C
N.pachyderma
pachyderrna
(sinistral
anddextral)
dextral)
atsite
site610
610 latitude productivity increased in response to greater nutrient
latitude productivityincreasedin responseto greaternutrient
were also
also lower
were
lower than
thanlatest
latestPliocene
Pliocenevalues
values[Jansen
[Jansenand
andSejrup,
Sejrup,
concentrations,
the
regions,
concentrations,
the nutrient-depleted
nutrient-depleted
regions,such
suchas
asthe
theNorth
North
1987].
1987]. One
Onemight
mightargue
arguethat
thatdata
datafrom
fromthe
theNorwegian
NorwegianSea
Sea are
are
Atlantic,
should
exhibit
a
smaller
613C
decrease
than
Atlantic,shouldexhibita smallerb•3Cdecrease
thanthe
themean
mean
more
relevant,
because
this
is
where
most
deep
water
forms
more relevant, becausethis is where most deep water forms
ocean
ocean(see
(seediscussion
discussionby
by Boyle
Boyle[1986]).
[1986]). If
If the
the decrease
decreasein
in the
the
except
perhaps
during
the
coldest
glaciations
[Duplessy
et
al.,
exceptperhapsduring the coldestglaciations[Duplessyet al.,
mean
ocean
6'3C
value
due
to
aaRedfield
ratio
nutrient
inventory
mean
ocean
b•3C
value
due
to
Redfield
ratio
nutrient
inventory
1992;
et
In summary,
planktonic
613C
1992;Labeyrie
Labeyrie
etal.,
al.,1992].
1992]. In
summary,
planktonic
•5•3C increase was fortuitously balanced by a non-nutrient-related
increase was fortuitously balanced by a non-nutrient-related
records from
from the
the Norwegian
Sea
rising
6'3C
values
over
records
Norwegian
Seaindicate
indicate
rising
•5•3C
values
over whole ocean 6'3C increase such as might occur due to the growth
whole
ocean
b•3Cincrease
such
asmight
occur
duetothegrowth
the
past
1.5
m.y.,
consistent
with
increasing
6'3C
values
in
the
thepast1.5m.y.,consistent
withincreasing
•5•3C
values
in the of the terrestrial biosphere [Shackleton, 1977], to a reduction in
of the terrestrialbiosphere[Shackleton,1977], to a reductionin
source waters
waters for
for NADW
as the
for rising
source
NADW as
theexplanation
explanation
for
rising6'3C
•5•3C 6'3C values or C/P ratios of buried organic matter, or to an
b•3Cvaluesor C/P ratiosof buriedorganic
matter,or to an
values
at
sites
502
and
552.
Planktonic
6'3C
records
spanning
the
values
atsites
502and552.Planktonic
•5•3C
records
spanning
the increase in the weathering of carbonates relative to organic
increase
in
the
weathering
of
carbonates
relative
to organic
entire past
past 2.6
entire
2.6 m.y.
m.y. from
from the
theNorwegian
NorwegianSea
Seawould
wouldbe
be helpful
helpfulin
in
matter,
then
the
Atlantic-Pacific
8'3C
gradient
could
increase
matter,
then
the
Atlantic-Pacific
b•3C
gradient
could
increase
further assessing
this
further
assessing
thispossibility.
possibility.
without
a
decrease
in
Pacific
6'3C
values,
as
is
observed.
without
a
decrease
in
Pacific
b•3C
values,
as
is
observed.
Why
might
northern
source
water
6'3C
values
have
increased
Whymightnorthern
source
water•3C values
haveincreased Additional data are needed, both to confirm the increase in source
data are needed, both
increasein source
through
time? Examination
through time?
Examinationof
of the
theevolution
evolutionof
of the
the AtlanticAtlanticwater
6'3C
values
and
to
evaluate
possible
reasons
for
water
b•3C
values
and
to
evaluate
possible
reasons
forthe
the
Pacific 613C
gradient provides
provides an
an important
constraint
when
Pacific
•5•3Cgradient
important
constraint
when increase.
increase.
considering
this question.
question. Due
in
values
at
considering
this
Dueto
tothe
theincrease
increase
in6'3C
•513C
values
at
site
(552-849)
8'3C
gradient
was
site552,
552,the
theAtlantic-Pacific
Atlantic-Pacific
(552-849)
•5•3C
gradient
wasgreater
greater Implications of %UNADW502 Changes on Northward Heat
Implications of %UNADWs02 Changeson Northward Heat
in
than it
it was
in the
the late
late Pliocene.
Pliocene. Raymo
in the
the late
late Pleistocene
Pleistocenethan
wasin
Raytnoet
et
Transport
Transport
al.
rather
al. [1990]
[ 1990] found
foundaa smaller
smallergradient
gradientin
in the
thelate
late Pleistocene,
Pleistocene,rather
than
than aa larger
larger one
one as
as we
we have
havefound
foundhere,
here, due
due to
to their
their use
use of
of the
the
site
of the
record. They
site677
677 record
recordinstead
insteadof
the site
site849
849 record.
Theyused
usedthe
thesite
site
As described
described above,
above, our
our UNADW502
UNADW2 calculations
suggest
that
As
calculations
suggest
that
the
contribution
of
UNADW
to
the
middepth
tropical
Atlantic
the contributionof UNADW to the middepthtropical Atlantic
during
remained
constant
552
552 records
records as
as their
their northern
northern source
source end-member
end-member as
as we
we have
have
duringinterglaciations
interglaciations
remainedapproximately
approximately
constantduring
during
may
here.
toward
the
in
6'3C
the past
past2.6
2.6 my.,
m.y.,but
butthe
theglacial
glacialcontribution
contribution
mayhave
haverisen
risen
here.The
Theincrease
increase
toward
thepresent
present
inthe
theAtlantic-Pacific
Atlantic-Pacific
•5•3C the
from about
about 80%
80% to
to 90%.
90%. By
et al.
al. [1990]
found
gradient
that
here
isiscaused
by
inin613C
By contrast,
contrast,Raymo
Raymoet
[ 1990] found
gradient
thatwe
wedescribe
describe
here
caused
bythe
theincrease
increase
•5•3C from
a dramatic
(from 80%
80% to
to 20%)
values
values at site
site 552
552 relative
relative to
to no
no increase
increaseat
at site
site849,
849, whereas
whereas the
the
a
dramatic reduction
reduction (from
20%) in
in the
theglacial
glacial
contribution
of
LNADW
to
the
deep
North
Atlantic
(site
decrease
in
the
613C
gradient
described
by
Raymo
et
al.
[1990]
is
contribution
of
LNADW
to
the
deep
North
Atlantic
(site607)
607)
decrease
in the•5•3C
gradient
described
byRayrno
etal. [1990]is
over the
the same
same interval.
interval. Northward
in feed
feed
caused
by aa larger
increase
at
Northwardoceanic
oceanicheat
heattransport
transportin
caused
by
larger6'3C
•5•3C
increase
atsite
site677
677than
thanat
atsite
site552
552 over
waters for
for NADW
NADW production
production greatly
climate of
of the
the
(Figure
above,
to
waters
greatlyinfluence
influencethe
the climate
(Figure9).
9). As
Asdiscussed
discussed
above,there
thereare
arereasons
reasons
tobelieve
believethat
that
site 849
6'3C values
are
of
deep
Pacific
site
849•513C
values
aremore
morerepresentative
representative
ofmean
mean
deep
Pacific
values
etal.,
values[Mix
[Mix et
al., 1995].
1995].
Assuming
that site
the
Assumingthat
site 849
849 rather
ratherthan
thansite
site677
677represents
represents
the
mean
6'3C
record,
several
possible
reasons
exist
meanocean
ocean
•5•3C
record,
several
possible
reasons
existfor
forthe
the
increase
with
increasein 6'3C
•5•3Cvalues
valueswhich
whichare
areconsistent
consistent
with an
anincrease
increasein
high-latitude North
North Atlantic
high-latitude
Atlantic and
and surrounding
surroundingland
land masses
masses
[Broecker et
et al.,
al., 1985],
[Broecker
1985], thus
thusit
it is
islogical
logicalto
to ask
askwhether
whetherthese
these
changes
changesin
in the
therelative
relativecontributions
contributionsof
ofLNADW
LNADW and
andUNADW
UNADW
played aa role
role in
in the
over the
the
played
theobserved
observedincreasing
increasingglacial
glacialseverity
severityover
past
this
past2.6
2.6 m.y.
m.y. Unfortunately,
Unfortunately,to
toaddress
address
thisquestion
questionexplicitly,
explicitly,
392
392
OPPO
RECORD
OPPOET
ET AL.:
AL.:A
A öt3C
•513C
RECORDOF
OFUPPER
UPPERNORTH
NORTHATLANTIC
ATLANTICDEEP
DEEPWATER
WATER
we must
we
must know
know the
the absolute
absolute fluxes
fluxes of
of both
both
LNADW
and
LNADW
and
over
past 2.6
about 80%
80% to
to
over the
the past
2.6 m.y.,
m.y., due
dueto
to aa small
smallincrease,
increase,from
from about
UNADW, and
per
UNADW,
andthe
theheat
heatreleased
released
perunit
unitflux
fluxof
ofeach
eachcomponent
component
of NADW.
for
of
NADW. While
Whilewe
wecan
canassume,
assume,
forsimplicity,
simplicity,that
thatthe
theheat
heat
about
%UNADW502;
the
about90%,
90%, in
inthe
theglacial
glacial
%UNADW502;
theinterglacial
interglacial
released per
released
per unit
unit flux
flux of
ofLNADW
LNADW and
andUNADW
UNADW remained
remained
constant through
constant
through time,
time, we
we cannot
cannotconstrain
constrainthe
theUNADW
UNADW and
and
LNADW flux
flux changes
changes that
that yield
in the
LNADW
yield the
the estimated
estimatedchanges
changesin
the
increase in
in glacial
is in
in contrast
to the
increase
glacial UNADW
UNADW contribution
contributionis
contrastto
the
much larger
larger decrease
in
to the
the deep
deep
much
decrease
in glacial
glacialLNADW
LNADWpercentage
percentage
to
North
Atlantic,
from
-80%
during
the
2-2.6
Ma
interval
to
-20%
NorthAtlantic,from-80% duringthe2-2.6Ma intervalto -20%
relative contribution
relative
contribution of UNADW
UNADW and
and LNADW
LNADW to sites
sites 502
502 and
and
over the
the past
past million
million years
years [Raymo
etal.,
over
[Raymoet
al.,19901.
1990].
contribution
has remained
approximately constant.
constant. The
contribution
has
remainedapproximately
The small
small
Covariance analysis
analysis of/5•80
of 8O and
b13C data
data from
from site
site 552,
at
Covariance
and/5•3C
552,at
2300 m
North
indicates
that
2300
m in
in the
thesubpolar
subpolar
NorthAtlantic,
Atlantic,
indicates
thatthroughout
throughout
the past
for
provides insight
the
past2.6
2.6 m.y.,
m.y.,there
therewas
wasaatendency
tendency
forhigher
higherglacial
glacialthan
than
provides
insight on
on northward
northwardheat
heattransport
transportunder
underdifferent
different
interglacial
'3C
in
the
middepth
Atlantic
relative
to
North
Atlantic
circulation
geometries.
Using
a
coupled
oceanNorth Atlantic circulationgeometries.Using a coupledocean- interglacial
•513C
in themiddepth
Atlantic
relative
tothe
thedeep
deep
Pacific. This
has
toward
the
as
atmosphere model
atmosphere
modelwith
withimproved
improvedsurface
surfaceheat
heatparameterization
parameterization Pacific.
Thistendency
tendency
hasweakened
weakened
toward
thepresent,
present,
aslowlow813C
southern source
waters
have
increasingly
penetrated
replacing the
replacing
the traditional
traditional restoring
restoring boundary
boundary condition
condition on
on
/513C
southern
source
waters
have
increasingly
penetrated
temperature, Rahmstorf
Rahmstorf [1994]
[1994] produced
produced simulations
northward
into the
temperature,
simulationsof
of deep
deep
northward
into
thedeep
deepnorth
northAtlantic
Atlanticand
andthe
thecore
coreof
ofglacial
glacial
ocean
circulation
having
three
different
equilibrium
states.
nutrient-depleted,
high-6'3C
waters
has
migrated
to
shallower
ocean circulation having three different equilibrium states. nutrient-depleted,
high-/513C
waters
hasmigrated
to shallower
Transitions between
between states
states were
depths.
2.6
NADW
Transitions
were achieved
achieved by
by imposing
imposing brief
brief
depths.From
Fromapproximately
approximately
2.6toto2.0
2.0Ma,
Ma,glacial
glacial
NADW
meltwater
pulses. One
corresponds
to
both
North
Atlantic. From
meltwaterpulses.
Oneof
ofthe
thethree
threestates
states
corresponds
to strong
strong influenced
influenced
boththe
thedeep
deepand
andmiddepth
middepth
NorthAtlantic.
From2.0
2.0
607,
607, respectively.
respectively.
A recent
A
recentmodeling
modelingstudy
studyby
byRahmstorf
Rahmsto•f[1994],
[1994],however,
however,
LNADW production,
the bottom
bottom of
of the
the
LNADW
production,with
with convection
convectionreaching
reachingthe
North
Atlantic.
In
the
other
two
states,
LNADW
is
not
produced,
North Atlantic. In theothertwo states,LNADW is not produced,
and
and maximum
maximum convection
convectiondepths
depthsreach
reachapproximately
approximately33 km.
km.
Because of
of the
used in
in this
Because
the new
new surface
surfaceheat
heatparameterization
parameterizationused
this
modeling
and
modelingexperiment,
experiment,surface
surfacetemperature
temperature
andheat
heattransport
transportare
are
not
not specified,
specified,but
but change
changeas
asaa result
resultof
of deep
deepocean
oceancirculation
circulation
changes.
important
finding
changes.There
Therewere
wereseveral
several
important
findingwhich
whichbear
bearon
onour
our
study.
to
and the
the
study.The
Theshallower
shallowercell
cellcorresponded
corresponded
to aa cool
coolclimate
climateand
deeper
cell corresponded
to aa warm
deeper convection
convection cell
correspondedto
warm climate,
climate, in
in
agreement
of
agreementwith
with reconstructions
reconstructions
of last
lastglacial
glacialversus
versusHolocene
Holocene
circulation
Duplessy et
etal.,
circulation[e.g.,
[e.g.,Boyle
Boyleand
andKeigwin,
Keigwin,1987;
1987;Duplessy
al.,1988;
1988;
Oppo
and Lehman,
Oppo and
Lehman, 1993]
1993] and
and with
with the
the results
resultsof
of this
thisstudy.
study.
Shallow
Shallow convection
convectionoccurred
occurredsouth
southof
of deep
deepconvection,
convection,as
as has
has
been
by the
the work
work of
of Labeyrie
Labeyrie et
et al.
al. [1992].
[1992]. The
beensuggested
suggestedby
The total
total
flux
flux of
of NADW
NADW was
was similar
similar for
for both
both the
the warm
warm and
and cold
cold climate,
climate,
implying
implying that
that UNADW
UNADW circulation
circulationwas
was more
more vigorous
vigorousduring
during
cold
cold climates,
climates,as
aswas
washypothesized
hypothesizedby
by 0ppo
Oppoand
andLehman
Lehman[1993]
[1993]
for
the
for the
the last
lastglaciation.
glaciation.Because
Because
themeridional
meridionalheat
heattransport
transportwas
was
found
found to
to be
be aa function
function of
of the
thelatitude
latitudeof
ofconvection,
convection,however,
however,
meridional
heat transport
lower in
in the
meridional heat
transportwas
was significantly
significantlylower
the cold
cold
climate
in the
climate simulations.
simulations. Thus,
climatethan
thanin
the warm
warm climate
Thus,although
althoughwe
we
cannot
of changes
cannot derive
derive measures
measuresof
changesin
in the
the absolute
absolutefluxes
fluxes of
of
UNADW
's
UNADW and
andLNADW
LNADW through
throughtime,
time,the
theresults
resultsof
of Rahms:orf
Rahmstorf's
[1994]
modeling
study
suggest
that
when
UNADW
is
favored
[1994] modelingstudy suggestthat when UNADW is favored
over
over the
the production
productionof
of LNADW,
LNADW, northward
northwardheat
heat transport
transportis
is
reduced.
reduced. Thus
Thus it
it is
is likely
likely that
that the
thechanges
changesin
in relative
relative
contributions
of LNADW
and UNADW
to the
contributions of
LNADW and
UNADW to
the deep
deep and
and
middepth
the past
past 2.6
2.6 m.y.,
m.y., described
described
middepthAtlantic,
Atlantic, respectively,
respectively,over
over the
here
here and
and by
by Raymo
Raymo et
et al.
al. [1990],
[1990], were
werecoupled
coupledto
to reduced
reduced
northward heat
heat transport,
transport, and
and played
a role
northward
played a
role in
in the
theNorthern
Northern
Hemisphere
over this
this interval.
interval. At
Hemisphereglacial
glacialintensification
intensification
over
At the
thevery
very
least,
gradual
shoaling
of
deep
water
during
glaciations
may
have
least,gradualshoalingof deepwaterduringglaciationsmay have
provided aa positive
provided
positivefeedback
feedbackfor
for cooling
coolingwhich
which occurred
occurreddue
due to
to
other factors.
other
factors.
Summary and
Summary
and Conclusions
Conclusions
to
above
to 1.0
1.0Ma,
Ma, NADW
NADW often
oftenshoaled
shoaled
abovesite
site607
607(3427
(3427m)
m)but
butstill
still
influenced
middepth
North
Atlantic
site
552
[Raymo
etal.,
influenced
middepth
NorthAtlanticsite552[Raymo
etal., 1990].
1990].
Over
over
Over the
thepast
past11 m.y.,
m.y.,and
andparticularly
particularly
overthe
thepast
past150
150kyr,
kyr,
UNADW
occasionally shoaled
shoaled above
m or
UNADW occasionally
above 2300
2300 m
or formed
formed
downstream
of site
1990;
downstream
of
site552
552 [Oppo
[Oppoand
andFairbanks,
Fairbanks,
1990;de
deMenoca!
Menocal
er
al.,
1992;
Oppo
and
Lehman,
1993].
Results
et al., 1992; Oppo and Lehman, 1993]. Resultsof aa recent
recent
modeling
1994]
that
modelingstudy
study[Rahmstorf,
[Rahmstorf,
1994]suggest
suggest
thatthis
thisgradual
gradual
shoaling
of NADW
shoalingof
NADW during
duringglaciations
glaciationsmay
may have
haveresulted
resultedin
in
reduced
meridional
heat
and
may
reduced
meridional
heattransport
transport
andhence
hence
mayhave
haveplayed
playedaa
role
that
over
rolein
in the
theglacial
glacialintensification
intensification
thatoccurred
occurred
overthe
thepast
past2.6
2.6
m.y.
Mean
'3C values
have
by
0.2
in both
Mean/5•3C
values
haverisen
risen
byabout
about
0.2%o
%0in
boththe
the
middepth
North Atlantic
tropical
middepthNorth
Atlantic(site
(site552)
552)and
andthe
themiddepth
middepth
tropical
Atlantic (Caribbean
(CaribbeanSea
Seasite
site 502)
502) over
over the
the past
past 2.6
2.6 m.y.,
my.,
Atlantic
apparently not
not due
due to
to aa mean
mean ocean
ö'3C
rise.
apparently
ocean
•5•3C
rise.We
Wehave
haveevaluated
evaluated
several
explanations
for
'3C rise.
rise. Although
aasmall
portion
several
explanations
forthe
the/513C
Although
small
portion
of the
in
of
the rise
riseat
at site
site502
502 may
maybe
bedue
dueto
toan
anincrease
increase
in northern
northern
source
water contribution
contribution relative
relative to
sources,
it is
is likely
likely
source
water
to southern
southern
sources,
it
contribution of northern
552
that the relative contribution
northern source
sourcewaters
waters to site 552
during glaciations
glaciations has
has been
been decreasing.
decreasing. We
that
during
Wesuggest
suggest
thataarise
risein
in
the
ö '3C
values of
water
also
the/5
•3Cvalues
of the
thesource
source
watermust
must
alsohave
haveoccurred.
occurred.
Additional high-resolution
high-resolution paleoceanographic
records,
especially
Additional
paleoceanographic
records,
especially
3C records
records of
of planktonic
foraminifera
from
water
/5•3C
planktonic
foraminifera
fromsource
source
water
regions,
the
regions,are
are needed
neededto
to understand
understand
thesignificance
significanceof
of PlioPlioPleistocene
8'3C
Pleistocene
•5•3Ctrends.
trends.
Acknowledgements.
We thank
thank Luping
Luping Zou
Acknowledgements. We
Zou and
andSusan
Susan
O'Conner-Lough
for
work,
Ostermann
for
O'Conner-Lough
formicroscope
microscope
work,Rindy
Rindy
Ostermann
foroverseeing
overseeing
most
Bill
mostof
of the
theisotope
isotopeanalyses,
analyses,
Bill Curry
Curryand
andDick
DickNorris
Norrisfor
foruseful
useful
discussions and
and reviews
reviews of
Nick
discussions
of an
anearlier
earlierversion
versionof
ofthe
themanuscript,
manuscript,
Nick
Shackleton for
for providing
providing the
the timescale
timescale for
Jansen
Shackleton
for site
site607,
607, and
andEystein
EysteinJansen
for sharing
unpublished data
data from
from site
site 610.
610. Reviews
for
sharingunpublished
Reviewsby
byB.
B.Flower,
Flower,R.
R.
Theideman, and
and K.
K. Miller
Miller are
are also
also greatly
greatly appreciated.
appreciated. We
thank Ernie
Ernie
Theideman,
We thank
Joynt for
for preparing
preparing the
the camera-ready
camera-ready copy.
copy. This
Joynt
Thiswork
workwas
wasfunded
fundedby
by
NSF grants
grants OCE9O-12279,
OCE9O-18382,and
andOCE91-02438.
OCE9I-02438. This
This is
is
NSF
OCE90-12279, OCE90-18382,
WHO! contribution
WHOI
contribution # 8735.
8735.
References
References
Our
that
Our results
resultsfrom
fromCaribbean
Caribbeansite
site502
502suggest
suggest
thatthe
thetendency
tendency Belanger, P. E., W. B. Curry, and R. K. Matthews, Core top evaluation of
P.E., W. B. Curry,andR. K. Matthews,
Coretopevaluation
of
'3C values
values in
for higher
higher glacial
for
glacialthan
thaninterglacial
interglacial
•513C
inthe
themiddepth
middepth Belanger,
benthic
benthicforaminiferal
foraminiferalisotopic
isotopicratios
ratiosfor
forpaleoceanographical
paleoceanographical
tropical Atlantic has persisted throughout the past 2.6 m.y.,
tropical Atlantic has persistedthroughoutthe past 2.6 m.y.,
largely
of
largelydue
dueto
to aagreater
greatercontribution
contribution
ofUNADW
UNADW during
duringglacial
glacial
than
difference
thaninterglacial
interglacialintervals.
intervals.The
Theglacial-interglacial
glacial-interglacial
differencein
in
the
of
slightly
thepercentage
percentage
of NADW
NADW to
to site
site502
502 may
mayhave
haveincreased
increasedslightly
interpretations,
Palaeogeogr. Palaeoclimat.
Palaeoecol.,
33,
interpretations,
Palaeogeogr.
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