Paleoenvironmental evolution of coastal Northern California - correlative evidence from the Pacific Ocean and adjacent
Linda E. Heusser (heusser@ldeo.columbia.edu) Lamont-Doherty Earth Observatory of Columbia University, John Barron (jbarron@usgs.gov), and Jason A. Addison (jaddsion@usgs.gov),
Coast Range for the past 16 ka
U.S. Geological Survey, MS 910, Menlo Park, California
119°W
118°W
43°N
Oregon Caves Natl. Mon.
42°N
ODP Site 1019
TN062 0550
127°W
126°W
125°W
Deglacial oscillations of pine, oak, and incense cedar,
alder (Alnus), and Douglas fir, reflect rapid changes in
precipitation and temperature during the Bølling-Allerød
and Younger Dryas climate events.
41°N
Rice Lake
124°W
123°W
122°W
121°W
40°N
120°W
119°W
118°W
Climate/Vegetation relationships in
North Coastal California
Montane pine
woodland
Oak Grassland
south of Rice Lake
Redwood (Sequoia)
and Alder (Alnus)
along the Eel River
Rice Lake Core 1979
Depth (m) Radiocarbon years BP
2.6
6370±110
3.35
6200± 110
4.35
8210± 100
5.9
8220±200
7.7-7.9
13650±850
Rice Lake, (40°02’ N; 123°30”’W,
1109 m elev.) lies in the transition
zone between mesic, northern
mixed oak hardwood-evergreen
forests (Quercus, Pinus,
Calocedrus/Juniperus) and more
arid southern oak foothill woodlands (Quercus) that borders the
western most edge of coastal
redwood (Sequoia sempervirens)
rainforest. The site, a wet
meadow on the tectonicallyactive Lake Mountain fault zone,
is a large (~15 ha), seasonally-dry
sagpond. Pollen assemblages
correspond with elevationrelated average annual precipitation and temperature that range
from (~25 cm and ~20° C in oak
woodland to ~95 cm and ~7° C
in montane pine and high montane juniper woodland (Barbour,
et al, 2007).
10
Comparison with ODP 1019
% of Assemblage
Maritine
Influence
Abies
Fir
10
Pseudotsuga
DOUGLAS FIR
Picea
SPRUCE
0
60
Southern Oak Woodland
50
Quercus
OAK
40
30
20
CHAPARRAL
20
Sequoia
Redwood
Alnus
ALDER
0
2
6
4
8
10
14
Cupressaceae
INCENSE CEDAR
Alnus
ALDER
10
5
Age (ka)
10
15
Long, J. and Whitlock, C., 2002. Fire and vegetation history from the Coastal
Rain Forest of the Western Oregon Coast Range.
Long, J., et al., 2007. Holocene vegetation and fire history of the Coast Range,
western Oregon, USA.
Zinke, P., 1977. The redwood forest and associated north coast forests. In
Barbour and Major. Terrestrial Vegetation of California.
20
12
14
16
Pinus
PINE
6
8
The only evidence of wetter conditions
between ~4 ka and 3 ka in the Rice Lake pollen
record is a 2-3 fold increase in pollen concentration. However, chronology in the younger
part of the Rice Lake record is limited.
Pinus
PINE
Alnus
ALDER
Quercus
OAK
4
6
8
Rhizosolenia
(coastal upwelling)
benthic diatoms
(transported from shelf )
10
0
60
N. seminae
(subarctic)
2
4
6
8
-9.8
Oregon National Monument, Cave Speleothem Record
18
(Ersek et al. (2012) correlate stalagmite δ O w/ winter air temperatures)
-9.4
40
-9.0
-8.6
cooler
0
0
6
8
10
12
14
16
ODP 1019 SST
During the ~4 to 3 ka wet interval in TN062
0550, benthic diatoms transported from the
shelf increase in relative abundance as does
the subarctic diatom, Neodenticula seminae,
possibly due to a southward migration of the
Subarctic North Pacific Front and concomitant
changes in regional atmospheric circulation.
Diatom proxies of coastal upwelling increase
at ~ 3 ka during the expansion of Sequoia.
TN062 Diatoms
F. doliolus (warm,
Central Gyre)
20
4
Pollen grains / gram
X1000
0
TN062 Pollen
wet
interval
2
2
2
4
Age (ka)
6
In TN062-0550, stepwise development of
coastal redwood occurred between ~ 6 and 5
ka and at ~3 ka, implying increased fog
associated with coastal upwelling. Wetter
conditions between ~4 and 3 ka are inferred
by the expansion of Alnus, which is associated
with seasonally flooded or permanently
saturated soils, and by the increase in
transported diatoms. (TN062 0550 chronology
after Addison, 2015 PACLIM poster.)
8
-8.2
Ersek et al. (2012) suggest that depleted
oxygen isotope values in their cave
speleothem record from the Oregon Caves
National Monument reflect cooling of winter
temperatures. The relative abundance trends
of Pinus in the Rice Lake pollen record display
a general agreement.
CONCLUSIONS
12
Cores from Rice Lake, ODP 1019, and TN062-0550 capture the development of North Coast Range vegetation that reflects changes in climate forcing, as well as tectonism, fire, and bedrock.
10
Between ~21 ka and ~15 ka, Rice Lake was surrounded by Pinus (pine)-dominated montane conifer forests with varying amounts of Picea (spruce),
Abies (fir), Calocedrus (Incense cedar),, and Pseudotsuga menziesii (Douglas fir) – implying cool, wet climate
mid Holocene
cool SSts
8
6
0
2
Sequoia Redwood (coastal fog)
10
Quercus
OAK
0
50
4
2
0
0
Alnus
ALDER
20
0
0
0
ODP 1019 Pollen
Sequoia
Redwood
(coastal
fog)
40
Pinus
PINE
?
Enhanced
ENSO
cycles?
Alnus
ALDER
Sequoia
Redwood
0
Poceae
GRASS
10
0
Barbour, M.G., et al, 2007. Terrestrial Vegetation of California.
Barron, J. A., et al, 2003. High-resolution climatic evolution of coastal northern
California during the past 16,000 years.
Clark, H.W., 1937. Association types in the North Coast Ranges of California.
Ersek, V., et al., 2012. Holocene winter climate variability in mid-latitude
western North America.
Lewis, J., et al., 2003. Sea fog off the California coast: Viewed in the context
of transient Weather systems.
Quercus
OAK
60
20
The expansion of Douglas fir at ~2 ka replacing oak
woodlands is observed elsewhere in the Eel River
landscape (Six Rivers National Forest report) and is likely
evidence of the inland penetration of coastal fog
associated with coastal upwelling.
40
?
0
The abrupt expansion of southern oak (Quercus)
woodlands at ~8.8 ka, followed by increased chaparral, is
accompanied by the continued decline of pine and alder.
Re-expansion of alder at ~5 ka is interpreted as a brief
interval of increased precipitation.
Holocene
60
0
REFERENCES
The age model for Rice Lake is based
on C14 ages of peat from a core taken
in 1979
80
Younger
Dryas
Montane Forest
20
30
Rice Lake Pollen
Mixed Evergreen Forest
% of Assemblage
Bølling/Allerød
20
4
% of Assemblage
Younger
Dryas
Relative pollen abundance (%)
30
Pinus
PINE
Speleothem δ18O (Ersek et al., 2012)
120°W
Pinus
PINE
40
Quercus
OAK
6
40
% of Assemblage
121°W
50
20
Pines dominated montane conifer forests (Pinus with
varying amounts of incense cedar (Cupressaceae),
hemlock (Tsuga), Douglas fir (Pseudotsuga), and spruce
(Picea)) from ~21 to 13 ka Climate envelopes of modern
montane conifer forest imply higher precipitation and
lower temperatures during the last glacial.
Marine cores TN062-0550 and ODP site 1019 lie in
the upwelling zone of northeast Pacific that borders
the unique Sequoia sempervirens (coastal redwood)
forests of the fogbound northern California and
southernmost Oregon coast (Lewis, et al., 2003).
Coastal fog and the maritime setting moderate July
temperatures (~ 13°C) and increase effective
moisture (fog drip ranges from ~18 -~30 cm)
(Zinke, 1977).
Rice Lake Pollen
60
Rice Lake Pinus %
122°W
60
Comparison with TN062 0550
Bølling/Allerød
123°W
70
Redwood relies on coastal fog
% of Assemblage
124°W
Holocene
Alkenone SST (°C)
125°W
80
Coastal Records
0
Relative pollen abundance (%)
126°W
Vegetation and Climate
Relative pollen abundance (%)
127°W
The Rice Lake Record
Relative pollen abundance (%)
This paper presents results of a coupled marine-terrestrial study that details
the past 16,000 years of coeval terrestrial and marine ecosystem changes in
northwestern coastal California. Pollen in a core taken from Rice Lake on the
North Fork of the Eel River, (40°02' N; 123°30’ W, 1109 m elevation) is compared
with pollen analyzed from two marine sediment cores: TN062-O550 taken ~13
km off the mouth of the Eel River (40°52’ N, 124°34’ W, water depth 550 m) and
ODP Site 1019 (41°40.9’ N; 124° 55,8’W, water depth 980 m) taken further north
~ 60 km offshore. The earliest portions of both the coastal and inland records
are dominated by pine (Pinus). Abrupt cooling of SSTs (sea surface temperatures) at ODP 1019 during the Younger Dryas coincides with a decrease in pine
and an increase in Alnus (alder) and Quercus (oak) at Rice Lake, indicating dry,
unstable conditions. A mosaic of mixed-evergreen forests and oak woodland at
Rice Lake, and redwood (Sequoia sempervirens) rainforests on the coast develops during the early middle part of the Holocene (~ 9 to 7 ka) coincident with
SST cooling at ODP 1019. An expansion of alder and oak between 4.0 and 3.0
ka in marine core TN062-0550 suggests a period of increased fluvial transport
tied to increased precipitation. Cool water diatoms and silicoflagellates
increase during this same time, possibly due to a southward migration of the
Subarctic North Pacific Front and concomitant changes in regional
atmospheric circulation. The current prominence of distinctive redwood rainforests on the northernmost California coast began with a rapid, two-fold
expansion of Sequoia at 3.0 ka that coincided with a stepwise increase in
diatom productivity (coastal upwelling). The expansion of Pseudotsuga
menziesii (Douglas fir) at Rice Lake at ~2 ka is likely evidence of the inland
penetration of coastal fog associated with coastal upwelling.
0
2
4
6
8
Age (ka)
Rapid oscillations of oak, chaparral, pine, incense cedar, Douglas fir and alder characterize deglacial climatic instability, e.g, Bølling-Allerød warming and Younger Dryas cooling and increased effective moisture.
10
12
14
16
20
Pollen data from Site 1019 document the overall replacement of glacial pine-dominated
conifer forests by stepwise expansion of coastal redwood at ~ 11 ka and ~5.2 ka. Postglacial
climate oscillations are reflected in rapidly shifting pine, oak, alder and redwood abundance.
The riparian/disturbance indicator alder peak during the Younger Dryas coincided with low
SST. Intensified (higher amplitude and more frequent) cycles of pine alternating with
increased alder and redwood pollen imply rapid changes in effective moisture and seasonal
temperature (enhanced El Niño–Southern Oscillation [ENSO] cycles) since ~3.5 ka.
The ~8.8 ka stepwise increase in oak at Ricke Lake closely approximates the ~8.4 ka decrease
in SST at ODP 1019.
Expansion of southern oak woodlands on the Franciscan melange, which has low available water holding capacity, imply early Holocene warming
and decreasing precipitation.
Off the coast (ODP 1019) beginning~ 16 ka, increasing amounts of alder punctuated the Late glacial pine-dominated montane forests. Low SST and
a peak in alder mark the cool, wet climate of the Younger Dryas.
A wet interval ~4 to 3 ka, is inferred from equal amounts of alder and coastal redwood in TN062-0550 and ODP 1019.
Subsequent, repeated oscillations in taxa of the modern coastal redwood forests suggest enhanced ENSO development.
Climate inferred from pollen-based vegetation reconstructions of the North Coast Range of California are similar to those from the Coast Range of
western Oregon (Long and Whitlock, 2002; Long, et al., 2007).