Earth and Planetary Science Letters 287 (2009) 412–419
Contents lists available at ScienceDirect
Earth and Planetary Science Letters
j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / e p s l
Latest on the absolute age of the Paleocene–Eocene Thermal Maximum (PETM): New
insights from exact stratigraphic position of key ash layers +19 and −17
Thomas Westerhold a,⁎, Ursula Röhl a, Heather K. McCarren b, James C. Zachos b
a
b
MARUM — Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, 28359 Bremen, Germany
Earth and Planetary Sciences, Univ. of California, Santa Cruz, CA 95064, USA
a r t i c l e
i n f o
Article history:
Received 27 February 2009
Received in revised form 17 August 2009
Accepted 18 August 2009
Available online 18 September 2009
Editor: T.M. Harrison
Keywords:
Eocene
Ar/Ar
ash layer
PETM
Geomagnetic Polarity Time Scale
ash − 17
a b s t r a c t
We constructed a precise early Eocene orbital cyclostratigraphy for DSDP Site 550 (Leg 80, Goban Spur, North
Atlantic) utilizing precession related cycles as represented in a high-resolution X-ray fluorescence based
barium core log. Based on counting of those cycles, we constrain the exact timing of two volcanic ash layers in
Site 550 which correlate to ashes + 19 and − 17 of the Fur Formation in Denmark. The ashes, relative to the
onset of the Paleocene–Eocene Thermal Maximum (PETM), are offset by 862 kyr and 672 kyr, respectively.
When combined with published absolute ages for ash − 17, the absolute age for the onset of the PETM is
consistent with astronomically calibrated ages. Using the current absolute age of 28.02 Ma for the Fish Canyon
Tuff (FCT) standard for calibrating the absolute age of ash − 17 is consistent with tuning option 2 in the
astronomically calibrated Paleocene time scale of Westerhold et al. (2008) [Westerhold, T., Röhl, U., Raffi, I.,
Fornaciari, E., Monechi, S., Reale, V., Bowles, J., and Evans, H.F., 2008, Astronomical calibration of the Paleocene
time: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 257, p. 377–403]. Using the recently recalibrated
absolute age of 28.201 Ma for the FCT standard is consistent with tuning option 3 in the astronomically
calibrated Paleocene time scale. The new results do not support the existence of any additional 405-kyr cycle in
the early Paleocene astronomically tuned time scale.
© 2009 Elsevier B.V. All rights reserved.
1. Introduction
During the late Paleocene and early Eocene the opening of the North
Atlantic was accompanied by enormous effusive and explosive
volcanism (Rea et al., 1990; Eldholm and Thomas, 1993) which
deposited volcanic ash layers over much of northern Europe (Knox
and Morton, 1988). Single-crystal (sanidine) 40Ar/39Ar dates from early
Eocene ash layers +19 and −17 in the Fur Formation of Denmark
(Bøggild, 1918) have played an important role in constructing the
Geomagnetic Polarity Time Scale (GPTS) (Cande and Kent, 1992, 1995;
Ogg and Smith, 2004) and for deciphering potential trigger mechanisms
of the transient global warming event known as the Paleocene–Eocene
Thermal Maximum (PETM) (Storey et al., 2007; Zachos et al., 2008).
The age of the PETM, for lack of a coincident and datable ash layer, has
to be derived by interpolating its position relative to the radiometric
dated ash −17 within magnetochron C24r (for discussion see Westerhold et al., 2007). Two factors are critical in this exercise: 1) the exact
distance between the PETM and ash −17, which is not known due to a
hiatus in the reference record from DSDP Site 550 (Aubry et al., 1996),
and 2) the accuracy of this radiometric age, which depends on the
correct absolute age of the Fish Canyon Tuff (FCT, ~28.02 Ma) sanidine
⁎ Corresponding author. Tel.: +49 421 21865672; fax: +49 421 2189865672.
E-mail address: twesterhold@marum.de (T. Westerhold).
0012-821X/$ – see front matter © 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.epsl.2009.08.027
reference standard (Villeneuve, 2004). Several recent advances should
help address these limitations and improve the absolute dating of the
PETM. First, the age of the FCT standard has been recalibrated and the
uncertainty of the method was reduced to 0.25% (Kuiper et al., 2008).
Second, an astronomically calibrated floating time scale has been
developed for the Paleocene based on the identification of the stable
long eccentricity cycle (405-kyr). The tuning yields three options for the
absolute age of the PETM (Westerhold et al., 2008) one of which (option
3) would be consistent with the new calibrated age of the K/Pg
boundary (Kuiper et al., 2008), but yields a relatively old age of 56.33 Ma
for the PETM. This age, however, is in strong conflict with existing
radioisotopic constraints. Furthermore, there seems to be a discrepancy
in the number of 405-kyr eccentricity cycles in early Paleocene records
(Hilgen et al., 2008; Kuiper et al., 2008).
Here we present a new cyclostratigraphy for Site 550 (Leg 80,
Goban Spur) based on a high-resolution trace metal records obtained
by X-ray fluorescence (XRF) core scanning to establish the exact
relative timing between the onset of the PETM and the prominent ash
layers + 19 and − 17. Both ashes are present in Site 550 and have
been correlated to the Danish ash series of the Fur Formation (Knox,
1984, 1985). Incorporating the latest radiometric dates for ash − 17,
we have estimated the absolute age range of the PETM to assess the
effect on the GPTS and test the astronomically calibrated Paleocene
time scale.
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
Fig. 1. Early Eocene (55.0 Ma) paleogeographic reconstruction showing the location of
DSDP Site 550 and ODP Site 1262. Reconstruction was made using Web-based software
at http://www.odsn.de/odsn/services/paleomap/paleomap.html (Hay et al., 1999).
2. Material and methods
We analyzed 50 m of sediment cores retrieved at the NE Atlantic
DSDP Site 550 (Fig. 1) using the non-destructive Super-slit X-ray
413
Fluorescence (XRF) Core Scanner equipped with an Oxford Neptune Xray tube and a Canberra X-pips detector at MARUM, Bremen University,
supported by the DFG-Leibniz Center for Surface Process and Climate
Studies at Potsdam University. The interval spanning Cores 550-29X
to -34X encompass the characteristic carbon isotope excursions (CIEs)
of the early Eocene transient warming events PETM (Cramer et al.,
2003) and Elmo (Lourens et al., 2005) (Fig. 2). High resolution late
Paleocene to early Eocene records from the South Atlantic show pronounced evidence of Milancovitch related orbital cyclicity in calcium,
iron, and barium which have been successfully utilized to construct a
detailed cyclostratigraphy for magnetochron C24r including the PETM
(Röhl et al., 2007; Westerhold et al., 2007). Similar variation in Ca, Fe,
and Ba content should be present in sediments recovered at Site 550 as
well and therefore be useful for establishing a cyclostratigraphy
between the PETM and Elmo.
The AVAATECH XRF core scanner acquires bulk-sediment chemical
data from split core surfaces. Although measured elemental intensities
are predominantly proportional to concentration, they are also influenced by the energy level of the X-ray source, the count time, and the
physical properties of the sediment (Tjallingii et al., 2007). Calcium,
Fig. 2. Bulk carbon isotope data (Cramer et al. 2003, Raffi et al. 2005) and XRF intensity data from DSDP Site 550 (zirconium in orange, titanium in green, barium in black, calcium in
blue, iron in red) of Cores 29X to 34X plotted against depth (mbsf). Transient global warming events PETM and Elmo (blue bar), the main ash deposits (turquoise bar), positions of
ash + 19 and − 17 (gray dashed lines), and the unconformity (solid black line marks) are indicated. The magnetostratigraphy and the lettering of carbon isotope transient decreases
after Cramer et al. (2003), the nannofossil biostratigraphy after Raffi et al. (2005), and the position of ash + 19 and − 17 after Knox (1984). (For interpretation of the references to
color in this figure legend, the reader is referred to the web version of this article.)
414
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
titanium, iron, zirconium, and barium data were collected every 2 cm
down-core over a 0.5 cm2 area. For the lighter elements calcium,
titanium, and iron we used a generator setting of 10 kV, an X-ray current
of 0.2 mA, and a sampling time of 20 s. For the heavier elements
zirconium and barium we used a generator setting of 50 kV, an X-ray
current of 1.0 mA, and a sampling time of 30s. The complete data set
presented is available online in the WDC-MARE PANGAEA database
(http://doi.pangaea.de/10.1594/PANGAEA.726654).
3. Results
XRF elemental data for Site 550 exhibits variability that can be
directly attributed to lithology (Fig. 2). The dominant lithology is
nannofossil chalk with high carbonate contents of up to 70%
(Shipboard Scientific Party, 1985) expressed as generally high Ca
values. Lower Ca values are present prior to the PETM reflecting
siliceous marls and dissolution intervals (Aubry et al., 1996) including
the carbon isotope excursions designated F, G, H1 (equivalent of Elmo
or ETM-2, Lourens et al., 2005), H2, and I1 in accord with the system
introduced by Cramer et al. (2003). The Fe and Ca intensities are anticorrelated with lowest Ca values in the carbonate dissolution interval
from 411.7 to 409.8 mbsf (Raffi et al., 2005). A stratigraphic
unconformity (Shipboard Scientific Party, 1985; Aubry et al., 1996)
at 407.38 mbsf is characterized by a transition from green to red
sediments, but with no change in Fe abundance. The Ba intensity data
show extremely well developed cycles especially in Cores 30X to 33X
(365–401 mbsf) which encompass both ash layers + 19 (392.99 mbsf)
and − 17 (399.76 mbsf). Ti values are generally low except for the ash
rich horizons in Cores 32X and 33X (384 to 401 mbsf). Apart from
several significant Zr peaks in a few distinct ash layers the acquired Zr
data are below detection limit (Figs. 2 and 3).
4. Ash layer identification
A series of over forty ash layers appearing as thin bentonites have
been identified in Hole 550 (Shipboard Scientific Party, 1985). Their
chemical characteristics and timing match with widespread ash series in
northwestern Europe, especially the North Sea Basin, in the latest
Paleocene and earliest Eocene (Nannofossil-Zone NP9/NP10) (Knox,
1984, 1985; Müller, 1985). The tuffaceous intervals in the North Sea
basin are contemporaneous with the 2nd phase of the North Atlantic
Igneous Province (NAIP) volcanism from 53 to 56 Ma (Saunders et al.,
1996) and diagnostic part of the Sele and Balder Formation in drill cores
from the North Sea (Knox, 1996). Around 180 individual fairly well
preserved ash layers are exposed in coastal cliffs around Limfjorden
(NW Denmark) in the Fur Formation (Larsen et al., 2003) and are identified as fall-out pyroclastics in water (Haaland et al., 2000). The succession has been divided into two visually distinctive parts: the lower
part with the mostly light colored ash layers of the ‘negative’ series
(−39 to −1) and the upper part with the black basaltic ash layers of the
‘positive’ series (+1 to +140) (Bøggild, 1918; Larsen et al., 2003). The
transition from negative to positive series represents the switch from
effusive to explosive volcanism (Larsen et al., 2003). Because both ash
+19 and ash −17 have a distinctive feldspar composition it was
possible to also identify them in ashes recovered at DSDP Site 550 at
392.99 and 399.76 mbsf, respectively (Knox, 1984, 1985).
Valuable information with respect to the ash layers can be obtained
from analysis of bulk sediment looking at the distribution of immobile
elements such as Ti and Zr (Haaland et al., 2000; Larsen et al., 2003).
Apart from two rhyolitic layers (+13 and +19) the positive series
originate from evolved Fe–Ti rich tholeiitic basalts (Larsen et al., 2003)
and can be identified in the XRF data by their characteristic high Fe, Ti
and Zr peaks as well as low Ca peaks (Figs. 2 and 3). The basaltic ash
layers in the XRF record from 385 to 395 mbsf represent the main phase
Fig. 3. Close up of XRF data in the bentonite rich interval at Site 550 against depth (mbsf). Zirconium in orange, titanium in green, barium in black, calcium in blue, and iron in red.
Position of ash + 19 and − 17 are marked by blue bars. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
(Phase 2b of Knox and Morton, 1983) of the ash deposits at Site 550.
Within this phase the rhyolitic peralkaline ash +19 is particularly
distinctive because it lies outside the compositional field of basalt in the
positive series (Larsen et al., 2003). In the XRF data this particular ash
layer shows a small peak in Ti and low Fe, Ba, and Zr intensities (Fig. 3)
being consistent with the geochemical characterization of Larsen et al.
(2003). Based on calculations of the total ash volume ejected ash +19 is
thought to be one of the largest basaltic pyroclastic eruptions in
geological history (Egger and Brückl, 2006). Most prominent is the
phonolitic to trachytic ash − 17 of the negative ash series (Larsen
et al., 2003) because it contains crystals of sanidine suitable for high
precision radiometric dating (Storey et al., 2007). The low Ti and high
Zr composition points to an alkaline magma type (Larsen et al., 2003).
The Danish ash − 17 is isochronous with the Skraenterne Formation
415
tuff in East Greenland (Storey et al., 2007) and has been proposed to
originate in the East Greenland Gardiner Complex (Heister et al.,
2001; Storey et al., 2007). Ash − 17 can be easily identified in the XRF
data from Site 550 due to the prominent Zr peak at 399.76 mbsf
(Figs. 2 and 3). A high Ba peak, a small Ti peak as well as lows in Ca and
Fe intensities are consistent with geochemical analysis of ash − 17
(Larsen et al., 2003).
5. Cyclostratigraphy
Given the sedimentation rates, it is clear that the primary oscillations
in Ba intensity are related to precession cyclicity. Blackman–Tukey and
evolutionary wavelet analysis methods were applied using AnalySeries
(Paillard et al., 1996) and the wavelet software of Torrence and Compo
Fig. 4. Evolutionary wavelet power spectra of Ba intensity data from DSDP Site 550 against depth (a) and relative age with respect to the onset of the PETM (b). The shaded contours
in the evolutionary wavelet power spectra are normalized linear variances with blue representing low spectral power, and red representing high spectral power. The black contour
lines enclose regions of greater than 95% confidence. Cross-hatched regions on either end indicate the cone of influence where edge effects become important. Note the distinct
bands that run across the spectra, which indicate the dominance of precession. The proposed position of the long (405 kyr) and short (100 kyr) eccentricity cycle as well as
precession (21 kyr) are indicated by arrows. Note: the age model in (b) is based on linear interpolation between the PETM and Elmo layer given the relative distance of ~ 1.8 Myr
(Westerhold et al., 2007) between both events. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
416
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
(1998) (http://paos.colorado.edu/research/wavelets), respectively. We
use the well developed cycles in the Ba intensity record of Site 550 to
develop a cyclostratigraphy. Ba is positively correlated with Ca and anticorrelated with Fe and Ti. This suggests that Ba in Site 550 sediments is
not of terrigenous origin. Therefore, Ba variations in Site 550 are
interpreted to predominately reflect changes in marine paleoproductivity (Paytan and Griffith, 2007) and thus the cyclic response of the
carbon cycle to climate forcing. Spectral analysis and evolutionary
wavelets of Ba intensities without ash layers reveal a distinct peak at
0.65 m (Fig. 4a). Age constraints for the distance PETM recovery to Elmo
(Westerhold et al. 2007) imply that the 0.65 m cycle has a mean period
of ~25 kyr which corresponds to earth's orbital precession cycle
(Fig. 4b). The absence of a strong shift in the period-band related to
precession (21 kyr, Fig. 4) suggests that stable and uniform sedimentation rates prevailed from the unconformity to the Elmo event. A
Gaussian filter was used to extract the dominant cyclicity (Fig. 5). We
then assigned the precession cycle numbers as given in Westerhold et al.
(2007) to the extracted cycles using the revised nannofossil biostratigraphy of Site 550 (Raffi et al., 2005) and Site 1262 (Agnini et al., 2007).
This way a correlation of cycles between Site 550 and Walvis Ridge sites
1262 and 1263 was established (Appendix A). Based on the fact that Ba
intensity maxima correspond to Fe intensity maxima and Ca intensity
minima at Walvis Ridge sites (Röhl et al., 2007), we assume that Ba
intensity maxima at Site 550 correspond to Ba cycle minima at Walvis
Ridge.
The accuracy was checked by comparing the bulk δ13C record
(Cramer et al., 2003; Raffi et al., 2005) with the orbitally tuned highresolution bulk δ13C record of ODP Site 1262 (McCarren and Zachos,
personal communication). The two δ13C curves match (Fig. 6) and
verify that the cyclostratigraphy of Site 550 is robust. Between the
unconformity (407.38 mbsf) and the PETM carbon isotope values at
Site 550 are stretched because of the lack of reliable tie points within a
condensed interval in the center of the CIE. The relative distance of
ashes + 19 and − 17 to the onset of the PETM and the relative position
with respect to magnetochron C24r based on the new cyclostratigraphy is shown in Table 1. We estimate that the error of the
cyclostratigraphy is less than two precession cycles.
6. Discussion
6.1. Relative distance of ash − 17 to the onset of the PETM
On the basis of a 40Ar/39Ar date for ash −17 and its relative distance
to the PETM at Site 550 an age of 55.0 Ma was assigned to the NP9/NP10
zonal nannofossil boundary (Swisher and Knox, 1991). Both Cande and
Kent (1992, 1995) and Berggren et al. (1995) utilized this age as a tie
point for their time scales. Because this calibration point was deemed
flawed (Aubry et al., 1996), Ogg and Smith (2004) placed ash −17
midway through C24r based on the magnetostratigraphy of Site 550,
and then applied the age of 55.07 ± 0.5 Ma derived by J. D. Obradovich
(see postscript of Berggren et al., 1995) to the middle of C24r in the new
GPTS2004. All these assumptions, however, are void because of a critical
unconformity in the Site 550 record between the ash layers and the
PETM. Wei (1995) concluded that the exact magnetostratigraphic
position of ash −17 and the NP9/NP10 boundary could not be
determined because of hiatuses. Nonetheless, an attempt was made to
orbitally calibrate a stacked composite bulk carbon isotope record for
four DSDP and ODP Sites. This effort, yielded relative ages of 440 kyr and
240 kyr post the CIE for ashes +19 and −17, respectively (Cramer et al.,
2003).
With benefit of the new cyclostratigraphy for the Walvis Ridge sites
(Röhl et al., 2007; Westerhold et al., 2007) the revised Site 550 chronology
places ashes +19 and −17 at 862 and 672 kyr, respectively, after the
onset of the CIE (Table 1). Moreover, ash −17 is located at a point 57%
through C24R. This confirms that hiatuses at Site 550 compromised the
astronomical calibration of the carbon isotope stack as proposed by
Cramer et al. (2003), although the relative distance between ash layers
+19 and −17 is similar (~200 kyr). The revised relative stratigraphy
now also suggests that the positive ash series (+1 to +140) in Denmark
was deposited within ~300 kyr instead of the proposed ~600 kyr by
Egger and Brückl (2006).
6.2. Implications for the absolute age of the PETM
With more precise constraints on the timing of ash −17 relative to
the onset of the PETM, we can now constrain the absolute age of the
PETM, and consider the implications for the orbitally calibrated
Paleocene time scale. An absolute age calibration for the PETM is still
unattainable because of uncertainties in both radiometric dating and
orbital solutions (Westerhold et al., 2007, 2008). The primary sources of
uncertainty include: (1) a 2.5% error propagation in Ar/Ar geochronology because of uncertainties in the ages of standards and radioactive
decay rates (also see Renne et al., 1998a,b; Min et al., 2000), and (2) the
chaotic diffusion in the orbital solutions beyond ~42 Ma (Laskar et al.,
2004) which does not allow for precise computation of minima in the
very long eccentricity cycle needed for accurate orbital tuning of the
early Cenozoic. However, because of its overall stability, the long eccentricity cycle (405 kyr) can be used for orbital tuning (Varadi et al., 2003;
Laskar et al., 2004) to develop a floating time scale (e.g., Hinnov and Ogg,
2007). This approach was used to successfully develop a cycle based
chronology for the entire Paleocene epoch (Westerhold et al., 2008).
This cyclostratigraphy presents three different tuning options offset by
one long eccentricity cycle resulting into three possible absolute age
estimates of 55.53, 55.93 and 56.33 Ma, respectively for the PETM
(Fig. 7).
In order to obtain an absolute age for the PETM from the new cycle
record of Site 550 we need a precise radiometric age for ash +19 and/or
ash −17. The most precise age has been obtained from multiple — as
well as single grain 40Ar/39Ar laser-fusion determinations on sanidines
from ash −17 (Storey et al., 2007). According to this study ash −17 has
an absolute age of 55.12 ± 0.12 Ma calibrated to a standard monitor age
of 28.02 Ma for the FCT (Renne et al., 1998b; Villeneuve, 2004).
Assuming a 672 kyr duration between ash −17 and the onset PETM,
and an error of ±21 kyr in the cyclostratigraphic position of ash −17,
coupled with a ±120 kyr uncertainty in the radiometric age of ash −17,
we obtain an age range for the PETM of 55.651 to 55.933 Ma (Fig. 7). This
age would be consistent with the option 2 age (55.93 Ma) derived from
the astronomical calibration (Westerhold et al., 2008).
Alternatively, with the new astronomically recalibrated age for the
FCT of 28.201 Ma (Kuiper et al., 2008), the ash −17 age of Storey et al.
(2007) must be corrected to 55.48± 0.12 Ma. In this case the age range
for the PETM would be from 56.011 to 56.293 Ma between option 2 and
option 3 of Westerhold et al. (2008) (Fig. 7). Because the age range is
closer to option 3 we suggest that the radiometric age of the ash −17
might be slightly older, about 55.15 Ma, as already shown in Fig. S1 of
Storey et al. (2007). If so, the age of the K/Pg boundary of 66.08 Ma
derived from astronomically calibrated stratigraphic framework for the
Paleocene would be consistent with the revised astronomical age of
65.95 Ma (Kuiper et al., 2008) finally eliminating the dating dilemma
between cyclostratigraphy and radiometric dating (Westerhold et al.,
2008).
Still a discrepancy exists in the number of 405-kyr cycles in the
older part of the Paleocene in the Zumaia record in Spain (Kuiper et al.,
2008) which, if verified, would prevent the construction of a tuned and
stable Paleocene time scale (Hilgen, 2008). One additional 405-kyr
cycle was found in Zumaia for the interval between the K/Pg boundary
and the top of the normal polarity interval of C28n compared to Walvis
Ridge (South Atlantic) and Shatsky Rise (NW Pacific) records (Westerhold et al., 2008). One additional 405 kyr cycle, would require an age of
55.93 Ma for the PETM in order to be consistent with the recalibrated
age of the K/Pg boundary of 65.95 Ma. However, this estimate would
be inconsistent with the calibrated age of the PETM using the relative
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
417
Fig. 5. Cyclostratigraphy for Cores DSDP 550-30X and -31X(a), -32X and -33X (b), and -34X (c) using high-resolution XRF barium (black) and calcium (blue) intensity data. The
precession-related cycles have been extracted by Gaussian filtering. The filters have been adjusted according to the proposed change in cycle thickness by detailed wavelet analysis.
Numbers indicate the number of precession cycles relative to the onset of the PETM as in Westerhold et al. (2007). Position of ashes + 19 and − 17 according to Knox (1984);
position of nannofossil markers after Raffi et al. (2005). [Precession filter details: a, 365 to 374 mbsf at 1.61 ± 0.483 cycle/m (c/m). 375 to 383 mbsf at 1.46 ± 0.438 c/m. b, 384 to
393 mbsf at 1.55 ± 0.465 c/m. 394 to 401 mbsf at 1.53 ± 0.459 c/m. c, 403 to 408 mbsf at 1.46 ± 0.438 c/m.] (For interpretation of the references to color in this figure legend, the
reader is referred to the web version of this article.)
418
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
Fig. 6. Bulk carbon isotope data from ODP Site 1262 (green; McCarren and Zachos, personal communication) and DSDP Site 550 (black; Cramer et al., 2003; Raffi et al., 2005), and XRF
data from Site 550 (Ca in blue, Ba in black, Ti in green, Zr in orange) plotted relative to the onset of the PETM. The age model for 550 is based on the cyclostratigraphy developed in this
study, the age model for 1262 is from Westerhold et al. (2007). Data from ash layers have been removed from the Ca and Ba data. Blue bars mark the transient global warming events
PETM and Elmo, the turquoise bar marks the main ash deposits, the gray dashed lines mark the positions of ash layers + 19 and − 17, and the solid black line the unconformity at Site
550. Note that the interval prior to the unconformity at Site 550 is condensed. The lettering of carbon isotope transient events is after Cramer et al (2003). (For interpretation of the
references to color in this figure legend, the reader is referred to the web version of this article.)
distance of ash −17 and a FCT standard age of 28.201 Ma. Because the
tuning of Westerhold et al. (2008) provides a solution which is
consistent with both the age of the ashes and the relative durations of
the Paleocene section in relation to the PETM and the K/Pg boundary,
our findings suggest the tuning of Zumaia might be in error. These issues
will be resolved when precise ages for +19 ash are available and the
detailed ash −17 correlation might get confirmed in other sections.
the FCT sanidine standard age. The new results suggest that the
recalibrated FCT standard age of 28.201 Ma (Kuiper et al., 2008) is
consistent with tuning option 3 in the astronomically calibrated
7. Conclusion and perspectives
High-resolution XRF data from DSDP Site 550 enabled us to construct
a reliable cyclostratigraphy for the early Eocene. The established
cyclostratigraphy is consistent with the ODP Leg 208 Walvis Ridge
cyclostratigraphy (Westerhold et al., 2007) and for the first time
provides the exact relative position of ash layers +19 and −17 within
magnetochron C24r. The combination of the most recent radiometric
age estimates for ash −17 and the here within newly constrained
distance between ash −17 and the onset of the PETM results in new
possible absolute age ranges for the PETM with respect to absolute age of
Table 1
Position of ash + 19 and − 17 in DSDP Site 550 with respect to magnetochron C24r and
the onset of the PETM.
Ash
DSDP Site 550 depth
(mbsf)
Relative position
in C24r
Relative distance to onset PETM
(kyr)
+ 19
− 17
392.99
399.76
C24r.37a
C24r.43a
862 ± 21
672 ± 21
a
inverted stratigraphic placement relative to the present (see text).
Fig. 7. Absolute age range for the onset of the PETM (gray bars) based on the age (Storey
et al., 2007) and relative distance (this study) of ash − 17 with respect to the age of the
Fish Canyon Tuff (FCT) sanidine standard of 28.02 Ma (Villeneuve, 2004) and
28.201 Ma (Kuiper et al., 2008). Horizontal black lines mark the three possible options
of the age range for the onset of the PETM based on the astronomically calibrated
Paleocene time scale (Westerhold et al., 2008).
T. Westerhold et al. / Earth and Planetary Science Letters 287 (2009) 412–419
Paleocene time scale (Westerhold et al., 2008) but do not support the
existence of any additional 405-kyr cycle in the early Paleocene record.
Acknowledgments
We are grateful to Dennis Kent and an anonymous referee for their
thorough reviews. This research was supported by the Deutsche
Forschungsgemeinschaft (DFG), the DFG-Leibniz Center for Surface
Process and Climate Studies at the University of Potsdam, and the
National Science Foundation (NSF Grant EAR-0628719). We are
indebted to the IODP Bremen Core Repository (BCR) staff for core
handling, and V. Lukies for her work in the XRF Core Scanner Lab at
MARUM. This research used samples and data provided by the Integrated
Ocean Drilling Program (IODP).
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at 10.1016/j.epsl.2009.08.027.
References
Agnini, C., Fornaciari, E., Raffi, I., Rio, D., Röhl, U., Westerhold, T., 2007. High-resolution
nannofossil biochronology of middle Paleocene to early Eocene at ODP Site 1262:
implications for calcareous nannoplankton evolution. Mar. Micropaleontol. 64,
215–248.
Aubry, M.-P., Berggren, W.A., Stott, L.D., Sinha, A., 1996. The upper Paleocene–lower Eocene
stratigraphic record and the Paleocene–Eocene boundary carbon isotope excursion:
implications for geochronology. In: Knox, R.W.O.B., Corfield, R.M., Dunay, R.E. (Eds.),
Correlation of the Early Paleogene in Northwest Europe: Geological Society Special
Publication, vol. 101, pp. 353–380.
Berggren, W.A., Kent, D.V., Swisher III, C.C., Aubry, M.P., 1995. A revised Cenozoic
geochronology and chronostratigraphy. In: Berggren, W.A., Kent, D.V., Aubry, M.P.,
Hardenbol, J. (Eds.), Geochronology, Time Scales and Global Stratigraphic Correlation:
SEPM, Spec. Publ., vol. 54, pp. 129–212.
Bøggild, O.B., 1918. Den vulkanske Aske i Moleret samt en Oversigt over Danmarks ældre
Tertiærbjærgarter.
Cande, S.C., Kent, D.V., 1992. A new geomagnetic polarity time scale for the late Cretaceous
and Cenozoic. J. Geophys. Res. 97, 13,917–13,951.
Cande, S.C., Kent, D.V., 1995. Revised calibration of the geomagnetic polarity timescale for
the Late Cretaceous and Cenozoic: J. Geophys. Res. 100, 6093–6095.
Cramer, B.S., Wright, J.D., Kent, D.V., Aubry, M.-P., 2003. Orbital climate forcing of δ13C
excursions in the late Paleocene–Eocene (chrons C24n–C25n). Paleoceanography 18,
1097. doi:10.1029/2003PA000909.
Egger, H., Brückl, E., 2006. Gigantic volcanic eruptions and climate change in the early
Eocene. Int. J. Earth Sci. (Geol. Rundsch.) 95, 1065–1070.
Eldholm, O., Thomas, E., 1993. Environmental impact of volcanic margin formation.
Earth Planet. Sci. Lett. 117, 319–329.
Haaland, H.J., Furnes, H., Martinsen, O.J., 2000. Paleogene tuffaceous intervals, Grane Field
(Block 25/11), Norwegian North Sea: their depositional, petrographical, geochemical
character and regional implications. Mar. Pet. Geol. 17, 101–118.
Hay, W.W., DeConto, R., Wold, C.N., Wilson, K.M., Voigt, S., Schulz, M., Wold-Rossby, A., Dullo,
W.-C., Ronov, A.B., Balukhovsky, A.N., Soeding, E., 1999. Alternative global Cretaceous
paleogeography. In: Barrera, E., Johnson, C. (Eds.), The Evolution of Cretaceous Ocean/
Climate Systems: Geological Society of America Special Paper, vol. 332, pp. 1–47.
Heister, L.E., O'Day, P.A., Brooks, C.K., Neuhoff, P.S., Bird, D.K., 2001. Pyroclastic deposits
within the East Greenland Tertiary flood basalts. J. Geol. Soc. (Lond.) 158, 269–284.
Hilgen, F.J., 2008. Recent progress in the standardization and calibration of the Cenozoic
Time Scale. Newsl. Stratigr. 43, 15–22.
Hilgen, F., Aubry, M.-P., Berggren, B., van Couvering, J., McGowran, B., Steininger, F.,
2008. The case for the original Neogene. Newsl. Stratigr. 43, 23–32.
Hinnov, L.A., Ogg, J.G., 2007. Cyclostratigraphy and the astronomical time scale. Stratigraphy
4, 239–251.
Knox, R.W.O.B., 1984. Nannoplankton zonation and the Palaeocene/Eocene boundary
beds of NW Europe: an indirect correlation by means of volcanic ash layers. J. Geol.
Soc. 141, 993–999.
Knox, R.W.O.B., 1985. Stratigraphic significance of volcanic ash in Paleocene and Eocene
sediments at Sites 549 and 550. In: Graciansky, P.C.D., Poag, C.W., et al. (Eds.), Initial
Reports DSDP, vol. 80. U.S. Government Printing Office, Washington, pp. 845–850.
Knox, R.W.O.B., 1996. Correlation of the early Paleogene in northwest Europe: an overview.
Spec. Publ. — Geol. Soc. Lond. 101, 1–11.
419
Knox, R.W.O.B., Morton, A.C., 1983. Stratigraphical distribution of early Palaeogene
pyroclastic deposits in the North Sea Basin: Proceedings of the Yorkshire Geological
Society, vol. 44, pp. 355–363.
Knox, R.W.O.B., Morton, A.C., 1988. The record of early Tertiary N Atlantic volcanism in
sediments of the North Sea Basin. In: Morton, A.C., Parson, L.M. (Eds.), Early Tertiary
Volcanism and the Opening of the NE Atlantic: Special Publications: London,
Geological Society, vol. 39, pp. 407–419.
Kuiper, K.F., Deino, A., Hilgen, F.J., Krijgsman, W., Renne, P.R., Wijbrans, J.R., 2008.
Synchronizing rock clocks of Earth history. Science 320, 500–504.
Larsen, L.M., Fitton, J.G., Pedersen, A.K., 2003. Paleogene volcanic ash layers in the Danish
Basin: compositions and source areas in the North Atlantic Igneous Province. Lithos 71,
47–80.
Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A., Levrard, B., 2004. A long-term
numerical solution for the insolation quantities of the Earth. Astron. Astrophys. 428,
261–285.
Lourens, L.J., Sluijs, A., Kroon, D., Zachos, J.C., Thomas, E., Röhl, U., Bowles, J., Raffi, I., 2005.
Astronomical pacing of late Palaeocene to early Eocene global warming events. Nature
435, 1083–1087.
Min, K., Mundil, R., Renne, P.R., Ludwig, K.R., 2000. A test for systematic errors in 40Ar/
39
Ar geochronology through comparison with U/Pb analysis of a 1.1-Ga rhyolite.
Geochim. Cosmochim. Acta 64, 73–98.
Müller, C., 1985. Biostratigraphic and paleoenvironmental interpretation of the Goban
Spur region based on a study of calcareous nannoplankton. In: Graciansky, P.C.D., Poag,
C.W., et al. (Eds.), Initial Reports DSDP, vol. 80. U.S. Government Printing Office,
Washington, pp. 573–599.
Ogg, J.G., Smith, A.G., 2004. The geomagnetic polarity time scale. In: Gradstein, F., Ogg, J.,
Smith, A. (Eds.), A Geological Timescale 2004. InCambridge University Press, pp. 63–86.
Paillard, D., Labeyrie, L., Yiou, P., 1996. Macintosh program performs time-series
analysis. Eos Trans. AGU 77 http://www.agu.org/eos_elec/96097e.html.
Paytan, A., Griffith, E.M., 2007. Marine barite: recorder of variations in ocean export
productivity. Deep-Sea Res., Part 2, Top. Stud. Oceanogr. 54, 687–705.
Raffi, I., Backman, J., Pälike, H., 2005. Changes in calcareous nannofossil assemblages
across the Paleocene/Eocene transition from the paleo-equatorial Pacific Ocean.
Palaeogeogr. Palaeoclimatol. Palaeoecol. 226, 93–126.
Rea, D.K., Zachos, J.C., Owen, R.M., Gingerich, P.D., 1990. Global change at the
Paleocene–Eocene boundary: climatic and evolutionary consequences of tectonic
events:. Palaeogeogr. Palaeoclimatol. Palaeoecol. 79, 117–128.
Renne, P.R., Karner, D.B., Ludwig, K.R., 1998a. Radioisotope dating: enhanced: absolute
ages aren't exactly. Science 282, 1840–1841.
Renne, P.R., Swisher, C.C., Deino, A.L., Karner, D.B., Owens, T.L., DePaolo, D.J., 1998b.
Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating:.
Chem. Geol. 145, 117–152.
Röhl, U., Westerhold, T., Bralower, T.J., Zachos, J.C., 2007. On the duration of the Paleocene–
Eocene thermal maximum (PETM). Geochem. Geophys. Geosyst. 8. doi:10.1029/
2007GC001784.
Saunders, A.D., Fitton, J.G., Kerr, A.C., Norry, M.J., Kent, R.W., 1996. The North Atlantic
igneous province. In: Mahoney, J.J., Coffin, M.F. (Eds.), Large Igneous Provinces:
Continental, Oceanic, and Planetary Flood Volcanism: Geophysical Monograph
Series, vol. 100.
Shipboard Scientific Party, 1985. Site 550. In: Graciansky, P.C.D., Poag, C.W., et al. (Eds.),
Initial Reports DSDP, vol. 80. U.S. Government Printing Office, Washington, pp.
251–355.
Storey, M., Duncan, R.A., Swisher III, C.C., 2007. Paleocene–Eocene thermal maximum
and the opening of the Northeast Atlantic. Science 316, 587–589.
Swisher III, C.C., Knox, R.W.O.B., 1991. The age of the Paleocene/Eocene boundary: 40Ar/
39
Ar dating of the lower part of NP10, North Sea Basin and Denmark (Abstract),
IGCP 308 (Paleocene/Eocene boundary events). International Annual meeting and
Field Conference, 2–6 December 1991. Brussels, p. 16.
Tjallingii, R., Röhl, U., Kölling, M., Bickert, T., 2007. Influence of the water content on Xray fluorescence core scanning measurements in soft marine sediments. Geochem.
Geophys. Geosyst. Tech. Brief 8. doi:10.1029/2006GC001393.
Torrence, C., Compo, G.P., 1998. A practical guide to wavelet analysis. Bull. Am. Meteorol.
Soc. 79, 61–78.
Varadi, F., Runnegar, B., Ghil, M., 2003. Successive refinements in long-term integrations of
planetary orbits. Astrophys. J. 592, 620–630.
Villeneuve, M., 2004. Radiogenic isotope geochronology. In: Gradstein, F., Ogg, J., Smith,
A. (Eds.), A Geological Timescale 2004. InCambridge University Press, pp. 87–95.
Wei, W., 1995. A short note on the Paleocene–Eocene transition in DSDP Hole 550.
Earth Planet. Sci. Lett. 131, 423–425.
Westerhold, T., Röhl, U., Laskar, J., Bowles, J., Raffi, I., Lourens, L.J., Zachos, J.C., 2007. On
the duration of magnetochrons C24r and C25n and the timing of early Eocene
global warming events: implications from the Ocean Drilling Program Leg 208
Walvis Ridge depth transect. Paleoceanography 22. doi:10.1029/2006PA001322.
Westerhold, T., Röhl, U., Raffi, I., Fornaciari, E., Monechi, S., Reale, V., Bowles, J., Evans, H.
F., 2008. Astronomical calibration of the Paleocene time. Palaeogeogr. Palaeoclimatol. Palaeoecol. 257, 377–403. doi:10.1016/j.palaeo.2007.09.016.
Zachos, J.C., Dickens, G.R., Zeebe, R.E., 2008. An early Cenozoic perspective on
greenhouse warming and carbon-cycle dynamics. Nature 451, 279–283.