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Book ; Online: Stable carbon and oxygen isotope compositions of benthic foraminifera N. truempyi samples and coarse fraction analyses from ODP Site 1209, supplementary data to: Westerhold, Thomas; R?hl, Ursula; Donner, Barbara; McCarren, Heather K; Zachos, James C (2011): A complete high-resolution Paleocene benthic stable isotope record for the central Pacific (ODP Site 1209). Paleoceanography, 26, PA2216

Westerhold, Thomas / Donner, Barbara / McCarren, Heather K / R?hl, Ursula / Zachos, James C

2011

Abstract: We have compiled the first stratigraphically continuous high-resolution benthic foraminiferal stable isotope record for the Paleocene from a single site utilizing cores recovered at Pacific ODP Site 1209. The long-term trend in the benthic isotope record ...

Abstract	We have compiled the first stratigraphically continuous high-resolution benthic foraminiferal stable isotope record for the Paleocene from a single site utilizing cores recovered at Pacific ODP Site 1209. The long-term trend in the benthic isotope record suggests a close coupling of volcanic CO2 input and deep sea warming. Over the short-term the record is characterized by slow excursions with a pronounced periodic beat related to the short (100-kyr) and long (405-kyr) eccentricity cycle. The phase relationship between the benthic isotope record and eccentricity is similar to patterns documented for the Oligocene and Miocene confirming the role of orbital forcing as the pace maker for paleoclimatic variability on Milankovitch time scales. In addition, the record documents an unusual transient warming of 2?C coeval with a 0.6 per mil carbon isotope excursion and a decrease in carbonate content at 61.75 Ma. This event, which bears some resemblance to Eocene hyperthermals, marks the onset of a long-term decline in d13C. The timing indicates it might be related to the initiation of volcanism along Greenland margin.
Language	English
Dates of publication	2011-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1029/2010PA002092
DOI	10.1594/PANGAEA.758023
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations, supplementary data to: Westerhold, Thomas; Bickert, Torsten; R?hl, Ursula (2005): Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations. Palaeogeography, Palaeoclimatology, Palaeoecology, 217(3-4), 205-222

Westerhold, Thomas / Bickert, Torsten / R?hl, Ursula

2005

Abstract: The middle Miocene delta18O increase represents a fundamental change in earth's climate system due to a major expansion and permanent establishment of the East Antarctic Ice Sheet accompanied by some effect of deepwater cooling. The long-term cooling ... ...

Abstract	The middle Miocene delta18O increase represents a fundamental change in earth's climate system due to a major expansion and permanent establishment of the East Antarctic Ice Sheet accompanied by some effect of deepwater cooling. The long-term cooling trend in the middle to late Miocene was superimposed by several punctuated periods of glaciations (Mi-Events) characterized by oxygen isotopic shifts that have been related to the waxing and waning of the Antarctic ice-sheet and bottom water cooling. Here, we present a high-resolution benthic stable oxygen isotope record from ODP Site 1085 located at the southwestern African continental margin that provides a detailed chronology for the middle to late Miocene (13.9-7.3 Ma) climate transition in the eastern South Atlantic. A composite Fe intensity record obtained by XRF core scanning ODP Sites 1085 and 1087 was used to construct an astronomically calibrated chronology based on orbital tuning. The oxygen isotope data exhibit four distinct delta18O excursions, which have astronomical ages of 13.8, 13.2, 11.7, and 10.4 Ma and correspond to the Mi3, Mi4, Mi5, and Mi6 events. A global climate record was extracted from the oxygen isotopic composition. Both long- and short-term variabilities in the climate record are discussed in terms of sea-level and deep-water temperature changes. The oxygen isotope data support a causal link between sequence boundaries traced from the shelf and glacioeustatic changes due to ice-sheet growth. Spectral analysis of the benthic delta18O record shows strong power in the 400-kyr and 100-kyr bands documenting a paleoceanographic response to eccentricity-modulated variations in precession. A spectral peak around 180-kyr might be related to the asymmetry of the obliquity cycle indicating that the response of the dominantly unipolar Antarctic ice-sheet to obliquityinduced variations probably controlled the middle to late Miocene climate system. Maxima in the delta18O record, interpreted as glacial periods, correspond to minima in 100-kyr eccentricity cycle and minima in the 174-kyr obliquity modulation. Strong middle to late Miocene glacial events are associated with 400-kyr eccentricity minima and obliquity modulation minima. Thus, fluctuations in the amplitude of obliquity and eccentricity seem to be the driving force for the middle to late Miocene climate variability.
Language	English
Dates of publication	2005-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1016/j.palaeo.2004.12.001
DOI	10.1594/PANGAEA.694041
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Sedimentary and carbonate preservation of ODP Sites 1262, 1263 and 1266, supplementary data to: Kelly, Daniel C; Nielsen, Tina MJ; McCarren, Heather K; Zachos, James C; R?hl, Ursula (2010): Spatiotemporal patterns of carbonate sedimentation in the South Atlantic: Implications for carbon cycling during the Paleocene-Eocene thermal maximum. Palaeogeography, Palaeoclimatology, Palaeoecology, 293(1-2), 30-40

Kelly, Daniel C / McCarren, Heather K / Nielsen, Tina MJ / R?hl, Ursula / Zachos, James C

2010

Abstract: Rapid carbon input into the ocean-atmosphere system caused a dramatic shoaling of the lysocline during the Paleocene-Eocene thermal maximum (PETM), a transient (~170 kyr) global warming event that occurred roughly 55 Ma. Carbon cycle models invoking an ... ...

Abstract	Rapid carbon input into the ocean-atmosphere system caused a dramatic shoaling of the lysocline during the Paleocene-Eocene thermal maximum (PETM), a transient (~170 kyr) global warming event that occurred roughly 55 Ma. Carbon cycle models invoking an accelerated carbonate-silicate feedback mechanism to neutralize ocean acidification predict that the lysocline would subsequently deepen to depths below its original position as the marine carbonate system recovered from such a perturbation. To test this hypothesis, records of carbonate sedimentation and preservation for PETM sections in the Weddell Sea (ODP Site 690) and along the Walvis Ridge depth transect (ODP Sites 1262, 1263, and 1266) were assembled within the context of a unified chronostratigraphy. The meridional gradient of undersaturation delimited by these records shows that dissolution was more severe in the subtropical South Atlantic than in the Weddell Sea during the PETM, a spatiotemporal pattern inconsistent with the view that Atlantic overturning circulation underwent a transient reversal. Deepening of the lysocline following its initial ascent is signaled by increases in %CaCO3 and coarse-fraction content at all sites. Carbonate preservation during the recovery period is appreciably better than that seen prior to carbon input with carbonate sedimentation becoming remarkably uniform over a broad spectrum of geographic and bathymetric settings. These congruent patterns of carbonate sedimentation confirm that the lysocline was suppressed below the depth it occupied prior to carbon input, and are consistent with the view that an accelerated carbonate-silicate geochemical cycle played an important role in arresting PETM conditions.
Language	English
Dates of publication	2010-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1016/j.palaeo.2010.04.027
DOI	10.1594/PANGAEA.738505
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Barium intensities and tie points between holes of Leg 208, supplementary data to: R?hl, Ursula; Westerhold, Thomas; Bralower, Timothy J; Zachos, James C (2007): On the duration of the Paleocene - Eocene Thermal Maximum (PETM). Geochemistry Geophysics Geosystems, 8(12), Q12002

R?hl, Ursula / Bralower, Timothy J / Westerhold, Thomas / Zachos, James C

2007

Abstract: The Paleocene - Eocene thermal maximum (PETM) is one of the best known examples of a transient climate perturbation, associated with a brief, but intense, interval of global warming and a massive perturbation of the global carbon cycle from injection of ... ...

Abstract	The Paleocene - Eocene thermal maximum (PETM) is one of the best known examples of a transient climate perturbation, associated with a brief, but intense, interval of global warming and a massive perturbation of the global carbon cycle from injection of isotopically light carbon into the ocean-atmosphere system. One key to quantifying the mass of carbon released, identifying the source(s), and understanding the ultimate fate of this carbon is to develop high-resolution age models. Two independent strategies have been employed, cycle stratigraphy and analysis of extraterrestrial Helium (HeET), both of which were first tested on Ocean Drilling Program (ODP) Site 690. Both methods are in agreement for the onset of the PETM and initial recovery, or the clay layer ("main body"), but seem to differ in the final recovery phase of the event above the clay layer, where the carbonate contents rise and carbon isotope values return toward background values. Here we present a state-of-the-art age model for the PETM derived from a new orbital chronology developed with cycle stratigraphic records from sites drilled during ODP Leg 208 (Walvis Ridge, Southeastern Atlantic) integrated with published records from Site 690 (Weddell Sea, Southern Ocean, ODP Leg 113). During Leg 208, five Paleocene - Eocene (P-E) boundary sections (Sites 1262 to 1267) were recovered in multiple holes over a depth transect of more than 2200 m at the Walvis Ridge yielding the first stratigraphically complete P-E deep-sea sequence with moderate to relatively high sedimentation rates (1 to 3 cm/kyr). A detailed chronology was developed with non-destructive X-ray fluorescence (XRF) core scanning records on the scale of precession cycles, with a total duration of the PETM now estimated to be ~ 170 kyr. The revised cycle stratigraphic record confirms original estimates for the duration of the onset and initial recovery, but suggests a new duration for the final recovery that is intermediate to the previous estimates by cycle stratigraphy and HeET.
Language	English
Dates of publication	2007-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1029/2007GC001784
DOI	10.1594/PANGAEA.667443
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Geochemistry of sediment core GeoB7920-2, supplementary data to: Tjallingii, Rik; R?hl, Ursula; K?lling, Martin; Bickert, Torsten (2007): Influence of the water content on X-ray fluorescence core- scanning measurements in soft marine sediments. Geochemistry Geophysics Geosystems, 8(2), Q02004

Tjallingii, Rik / Bickert, Torsten / K?lling, Martin / R?hl, Ursula

2007

Abstract: The X-ray fluorescence (XRF) core scanner provides bulk-sediment chemistry data measured nondestructively at the split core sediment surface. Although this method is widely accepted, there is little known about the effects of physical properties such as ... ...

Abstract	The X-ray fluorescence (XRF) core scanner provides bulk-sediment chemistry data measured nondestructively at the split core sediment surface. Although this method is widely accepted, there is little known about the effects of physical properties such as density and water content on XRF core scanner data. Comparison of XRF scanner measurements from the sediment surface and dry powder samples of sediment core GeoB7920 indicates strongly reduced element intensities for the lighter elements Al and Si. We relate the lower element intensities of the measurements taken at the sediment surface to the amount of water in the sample volume analyzed by the XRF core scanner. The heavier elements K, Ca, Ti, and Fe remain relatively unaffected by the variation of any physical property within sediment core GeoB7920. Additionally, we successfully use the elemental intensity of Cl as a proxy for the seawater content in the sample volume analyzed by the XRF core scanner. This enables the establishment of a correction function for the elements Al and Si that corrects for the radiation absorption of the water content in sediment core GeoB7920 off Cape Blanc, NW Africa.
Language	English
Dates of publication	2007-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1029/2006GC001393
DOI	10.1594/PANGAEA.761033
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Conference proceedings ; Online: Susceptibility, density, iron and calcium concentrations of ODP holes 165-999B and 165-1001A, supplementary data to: R?hl, Ursula; Abrams, Lewis J (2000): High-resolution, downhole, and nondestructive core measurements from Sites 999 and 1001 in the Caribbean Sea: application to the Late Paleocene Thermal Maximum. In: Leckie, RM; Sigurdsson, H; Acton, GD; Draper, G (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 165, 191-203

R?hl, Ursula / Abrams, Lewis J

2000

Abstract: Pelagic sediments recording an extreme and short-lived global warming event, the Late Paleocene Thermal Maximum (LPTM), were recovered from Hole 999B (Colombian Basin) and Holes 1001A and 1001B (lower Nicaraguan Rise) in the Caribbean Sea during Ocean ... ...

Abstract	Pelagic sediments recording an extreme and short-lived global warming event, the Late Paleocene Thermal Maximum (LPTM), were recovered from Hole 999B (Colombian Basin) and Holes 1001A and 1001B (lower Nicaraguan Rise) in the Caribbean Sea during Ocean Drilling Program Leg 165. The LPTM consists of a 0.3-0.97 m calcareous claystone to claystone horizon. High-resolution downhole logging (Formation MicroScanner [FMS]), standard downhole logs (resistivity, velocity, density, natural gamma ray, and geochemical log), and non-destructive chemical and physical property (multisensor core logger [MSCL] and X-ray fluorescence [XRF] core scanner) data were used to identify composite sections from parallel holes and to record sedimentological and environmental changes associated with the LPTM. Downhole logging data indicate an abrupt and distinct difference in physical and chemical properties that extend for tens of meters above and below the LPTM. These observations indicate a rapid environmental change at the LPTM, which persists beyond the LPTM anomaly. Comparisons of gamma-ray attenuation porosity evaluator (GRAPE) densities from MSCL logging on split cores with FMS resistivity values allows core-to-log correlation with a high degree of accuracy. High-resolution magnetic susceptibility measurements of the cores are compared with elemental concentrations (e.g., Fe, Ca) analyzed by high-resolution XRF scanning. The high-resolution data obtained from several detailed core and downhole logging methods are the key to the construction of composite sections, the correlation of both adjacent holes and distant sites, and core-log integration. These continuous-depth series reveal the LPTM as a multiphase event with a nearly instantaneous onset, followed by a much different set of physical and chemical conditions of short duration, succeeded by a longer transition to a new, more permanent set of environmental circumstances. The estimated duration of these 'phases' are consistent with paleontological and isotopic studies of the LPTM
Language	English
Dates of publication	2000-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Conference proceedings ; Online
Note	This dataset is supplement to doi:10.2973/odp.proc.sr.165.009.2000
DOI	10.1594/PANGAEA.735009
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Susceptibility, d13C and Iron of Site 171-1051, supplementary data to: Norris, Richard D; R?hl, Ursula (1999): Carbon cycling and chronology of climate warming during the Palaeocene/Eocene transition. Nature, 401(6755), 775-778

Norris, Richard D / R?hl, Ursula

1999

Abstract: Current models of the global carbon cycle lack natural mechanisms to explain known large, transient shifts in past records of the stable carbon-isotope ratio (delta13C) of carbon reservoirs. The injection into the atmosphere of ~1,200-2,000 gigatons of ... ...

Abstract	Current models of the global carbon cycle lack natural mechanisms to explain known large, transient shifts in past records of the stable carbon-isotope ratio (delta13C) of carbon reservoirs. The injection into the atmosphere of ~1,200-2,000 gigatons of carbon, as methane from the decomposition of sedimentary methane hydrates, has been proposed to explain a delta13C anomaly associated with high-latitude warming and changes in marine and terrestrial biota near the Palaeocene-Eocene boundary, about 55 million years ago. These events may thus be considered as a natural 'experiment' on the effects of transient greenhouse warming. Here we use physical, chemical and spectral analyses of a sediment core from the western North Atlantic Ocean to show that two-thirds of the carbon-isotope anomaly occurred within no more than a few thousand years, indicating that carbon was catastrophically released into the ocean and atmosphere. Both the delta13C anomaly and biotic changes began between 54.93 and 54.98 million years ago, and are synchronous in oceans and on land. The longevity of the delta13C anomaly suggests that the residence time of carbon in the Palaeocene global carbon cycle was ~120 thousand years, which is similar to the modelled response after a massive input of methane. Our results suggest that large natural perturbations to the global carbon cycle have occurred in the past-probably by abrupt failure of sedimentary carbon reservoirs-at rates that are similar to those induced today by human activity.
Language	English
Dates of publication	1999-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1038/44545
DOI	10.1594/PANGAEA.56149
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Eocene sedimentary calcium carbonate contents and stable isotope composition of benthic foraminifera, supplementary data to: Sexton, Philip F; Norris, Richard D; Wilson, Paul A; P?like, Heiko; Westerhold, Thomas; R?hl, Ursula; Bolton, Clara T; Gibbs, Samantha (2011): Eocene global warming events driven by ventilation of oceanic dissolved organic carbon. Nature, 471, 349-352

Sexton, Philip F / Bolton, Clara T / Gibbs, Samantha / Norris, Richard D / P?like, Heiko / R?hl, Ursula / Westerhold, Thomas / Wilson, Paul A

2011

Abstract: Hyperthermals' are intervals of rapid, pronounced global warming known from six episodes within the Palaeocene and Eocene epochs (~65-34 million years (Myr) ago) (Zachos et al., 2005, doi:10.1126/science.1109004; 2008, doi:10.1038/nature06588; Roehl et ... ...

Abstract	'Hyperthermals' are intervals of rapid, pronounced global warming known from six episodes within the Palaeocene and Eocene epochs (~65-34 million years (Myr) ago) (Zachos et al., 2005, doi:10.1126/science.1109004; 2008, doi:10.1038/nature06588; Roehl et al., 2007, doi:10.1029/2007GC001784; Thomas et al., 2000; Cramer et al., 2003, doi:10.1029/2003PA000909; Lourens et al., 2005, doi:10.1038/nature03814; Petrizzo, 2005, doi:10.2973/odp.proc.sr.198.102.2005; Sexton et al., 2006, doi:10.1029/2005PA001253; Westerhold et al., 2007, doi:10.1029/2006PA001322; Edgar et al., 2007, doi:10.1038/nature06053; Nicolo et al., 2007, doi:10.1130/G23648A.1; Quill?v?r? et al., 2008, doi:10.1016/j.epsl.2007.10.040; Stap et al., 2010, doi:10.1130/G30777.1). The most extreme hyperthermal was the 170 thousand year (kyr) interval (Roehl et al., 2007) of 5-7 ?C global warming (Zachos et al., 2008) during the Palaeocene-Eocene Thermal Maximum (PETM, 56 Myr ago). The PETM is widely attributed to massive release of greenhouse gases from buried sedimentary carbon reservoirs (Zachos et al., 2005; 2008; Lourenbs et al., 2005; Nicolo et al., 2007; Dickens et al., 1995, doi:10.1029/95PA02087; Dickens, 2000; 2003, doi:10.1016/S0012-821X(03)00325-X; Panchuk et al., 2008, doi:10.1130/G24474A.1) and other, comparatively modest, hyperthermals have also been linked to the release of sedimentary carbon (Zachos et al., 2008, Lourens et al., 2005; Nicolo et al., 2007; Dickens, 2003; Panchuk et al., 2003). Here we show, using new 2.4-Myr-long Eocene deep ocean records, that the comparatively modest hyperthermals are much more numerous than previously documented, paced by the eccentricity of Earth's orbit and have shorter durations (~40 kyr) and more rapid recovery phases than the PETM. These findings point to the operation of fundamentally different forcing and feedback mechanisms than for the PETM, involving redistribution of carbon among Earth's readily exchangeable surface reservoirs rather than carbon exhumation from, and subsequent burial back into, the sedimentary reservoir. Specifically, we interpret our records to indicate repeated, large-scale releases of dissolved organic carbon (at least 1,600 gigatonnes) from the ocean by ventilation (strengthened oxidation) of the ocean interior. The rapid recovery of the carbon cycle following each Eocene hyperthermal strongly suggests that carbon was resequestered by the ocean, rather than the much slower process of silicate rock weathering proposed for the PETM (Zachos et al., 2005; 2003). Our findings suggest that these pronounced climate warming events were driven not by repeated releases of carbon from buried sedimentary sources (Zachos et al., 2008, Lourens et al., 2005; Nicolo et al., 2007; Dickens, 2003; Panchuk et al., 2003) but, rather, by patterns of surficial carbon redistribution familiar from younger intervals of Earth history.
Language	English
Dates of publication	2011-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1038/nature09826
DOI	10.1594/PANGAEA.763158
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Paleonutrient and productivity records from the subarctic North Pacific, supplementary data to: Gebhardt, Holger; Sarnthein, Michael; Grootes, Pieter Meiert; Kiefer, Thorsten; K?hn, Hartmut; Schmieder, Frank; R?hl, Ursula (2008): Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V. Paleoceanography, 23, PA4212

Gebhardt, Holger / Grootes, Pieter Meiert / K?hn, Hartmut / Kiefer, Thorsten / R?hl, Ursula / Sarnthein, Michael / Schmieder, Frank

2008

Abstract: Our study addresses fundamental questions of the mode and timing of orbital and millennialscale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past ... ...

Abstract	Our study addresses fundamental questions of the mode and timing of orbital and millennialscale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past abundance of nutrients in surface waters despite strong stratification, and the North Pacific - North Atlantic seesaw of oscillations in sea surface temperature (SST). We do this by generating and interpreting multiple records for glacial terminations I-V down two long piston cores, one each from the western and eastern subarctic Pacific. Chlorins and biogenic opal are proxies for surface water productivity; delta 13C of epibenthic foraminifera is a record of deepwater ventilation; and the delta 13C of N. pachyderma sin. is a tracer of nutrients in subsurface waters that extend up to the sea surface during times of vertical mixing. The degree of mixing is traced by pairing SST and delta 18O records of planktic surface and subsurface (pycnocline) dwellers. Tight age control is deduced from a suite of age-calibrated 14C plateau boundaries for Termination I, and benthic ?18O, and geomagnetic events for the last 800 kyr. 14C paleoreservoir ages record the ages of surface and deep waters to uncover short-term changes in MOC over Termination I. We have defined a standard sequence of short-term productivity events for Termination I and subsequent interglacials, also evident during Terminations II to V over the last 450 ka. The peak-glacial regime of stable stratification and low productivity terminated, together with the end of ice rafting and melting, near 17 ka, ~2000 yr after the onset of Termination I. Pulses of vertical mixing and incursion of warm surface waters from the subtropics followed. Convected young water masses finally penetrated down to 2350 m water depth after a further 1500 yr, at ~14.5 ka, significantly improving bottom water ventilation through the late deglacial and earliest interglacial. Mixing with upwelled nutrients from the pycnocline induced shortterm maxima in algal production of chlorins and biogenic opal near 17-15 and 15-12 ka, respectively. Deglacial meltwater incursions in the Aleutian Current and silica input from North American rivers also promoted East Pacific productivity after 15.5 ka. Productivity decreased during the late deglacial and early interglacial, coeval with an exceptional peak in CaCO3 preservation caused by both low organic flux and well ventilated deepwater. Subsequently, low-salinity and cool surface waters and in turn, stratification were gradually restored. A second, opal-dominated productivity maximum marked the ends of interglacials. The deglacial pulses of vertical mixing around 17-11 ka imply an important contribution of the North Pacific to the coeval release of oceanic CO2 into the atmosphere and support the east-west seesaw model of climate change.
Language	English
Dates of publication	2008-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1029/2007PA001513
DOI	10.1594/PANGAEA.701578
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Book ; Online: Geochemistry and stratigraphy on sediment cores from Leg198 and Leg 208, supplementary data to: Westerhold, Thomas; R?hl, Ursula; Raffi, Isabella; Fornaciari, Eliana; Monechi, Simonetta; Reale, Viviana; Bowles, Julie; Evans, Helen F (2008): Astronomical calibration of the Paleocene time. Palaeogeography, Palaeoclimatology, Palaeoecology, 257(4), 377-403

Westerhold, Thomas / Bowles, Julie / Evans, Helen F / Fornaciari, Eliana / Monechi, Simonetta / R?hl, Ursula / Raffi, Isabella / Reale, Viviana

2008

Abstract: The first complete cyclic sedimentary successions for the early Paleogene from drilling multiple holes have been retrieved during two ODP expeditions: Leg 198 (Shatsky Rise, NW Pacific Ocean) and Leg 208 (Walvis Ridge, SE Atlantic Ocean). These new ... ...

Abstract	The first complete cyclic sedimentary successions for the early Paleogene from drilling multiple holes have been retrieved during two ODP expeditions: Leg 198 (Shatsky Rise, NW Pacific Ocean) and Leg 208 (Walvis Ridge, SE Atlantic Ocean). These new records allow us to construct a comprehensive astronomically calibrated stratigraphic framework with an unprecedented accuracy for both the Atlantic and the Pacific Oceans covering the entire Paleocene epoch based on the identification of the stable long-eccentricity cycle (405-kyr). High resolution X-ray fluorescence (XRF) core scanner and non-destructive core logging data from Sites 1209 through1211 (Leg 198) and Sites 1262, 1267 (Leg 208) are the basis for such a robust chronostratigraphy. Former investigated marine (ODP Sites 1001 and 1051) and land-based (e.g., Zumaia) sections have been integrated as well. The high-fidelity chronology is the prerequisite for deciphering mechanisms in relation to prominent transient climatic events as well as completely new insights into Greenhouse climate variability in the early Paleogene. We demonstrate that the Paleocene epoch covers 24 long eccentricity cycles. We also show that no definite absolute age datums for the K/Pg boundary or the Paleocene - Eocene Thermal Maximum (PETM) can be provided by now, because of still existing uncertainties in orbital solutions and radiometric dating. However, we provide two options for tuning of the Paleocene which are only offset by 405-kyr. Our orbitally calibrated integrated Leg 208 magnetostratigraphy is used to revise the Geomagnetic Polarity Time Scale (GPTS) for Chron C29 to C25. We established a high-resolution calcareous nannofossil biostratigraphy for the South Atlantic which allows a much more detailed relative scaling of stages with biozones. The re-evaluation of the South Atlantic spreading rate model features higher frequent oscillations in spreading rates for magnetochron C28r, C27n, and C26n.
Language	English
Dates of publication	2008-9999
Size	Online-Ressource
Publisher	PANGAEA - Data Publisher for Earth & Environmental Science
Publishing place	Bremen/Bremerhaven
Document type	Book ; Online
Note	This dataset is supplement to doi:10.1016/j.palaeo.2007.09.016
DOI	10.1594/PANGAEA.667122
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED

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Inter-library loan at ZB MED