Archaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion

Abstract A negative carbon isotope excursion recorded in terrestrial and marine archives reflects massive carbon emissions into the exogenic carbon reservoir during the Paleocene-Eocene Thermal Maximum. Yet, discrepancies in carbon isotope excursion estimates from different sample types lead to substantial uncertainties in the source, scale, and timing of carbon emissions. Here we show that membrane lipids of marine planktonic archaea reliably record both the carbon isotope excursion and surface ocean warming during the Paleocene-Eocene Thermal Maximum. Novel records of the isotopic composition of crenarchaeol constrain the global carbon isotope excursion magnitude to −4.0 ± 0.4‰, consistent with emission of >3000 Pg C from methane hydrate dissociation or >4400 Pg C for scenarios involving emissions from geothermal heating or oxidation of sedimentary organic matter. A pre-onset excursion in the isotopic composition of crenarchaeol and ocean temperature highlights the susceptibility of the late Paleocene carbon cycle to perturbations and suggests that climate instability preceded the Paleocene-Eocene Thermal Maximum.

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Drilling disturbance and constraints on the onset of the Paleocene/Eocene boundary carbon isotope excursion in New Jersey

Climate of the Past Discussions ◽

10.5194/cpd-10-3303-2014 ◽

2014 ◽

Vol 10 (4) ◽

pp. 3303-3325 ◽

Cited By ~ 1

Author(s):

P. N. Pearson ◽

E. Thomas

Keyword(s):

New Jersey ◽

Carbon Isotope ◽

Supporting Evidence ◽

Drilling Mud ◽

Ocean Drilling Program ◽

Surface Ocean ◽

Turbid Waters ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

The Impact

Abstract. The onset of the Paleocene/Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE; about 56 million years ago) was geologically abrupt but it is debated whether it took thousands of years or was effectively instantaneous. A significant new record of the onset of the CIE was published by Wright and Schaller (2013) who claimed that it could be resolved across 13 annual layers in a drill core through the Marlboro Clay at Millville, New Jersey (Ocean Drilling Program Leg 174X). Supporting evidence of similar layering was also reported from another New Jersey drill site, Wilson Lake B, and a photograph of the Marlboro Clay in outcrop. Such a short duration would imply an instantaneous perturbation of the atmosphere and surface ocean, and the impact of a comet or asteroid as the likely cause. However it was suggested by Pearson and Nicholas (2014) from the published photographs that the layers in the Marlboro Clay could be artifacts of drilling disturbance (so-called "biscuiting", wherein the formation is fractured into layers or "biscuits" and drilling mud is injected in between). Here we report new observations on the cores which support that interpretation, including concentric grooves on the surfaces of the biscuits caused by spinning in the bit, micro-fracturing at their edges, and injected drilling mud. We re-interpret the outcrop evidence as showing joints rather than sedimentary layers. We argue that foraminifer concentrations in the sediments are far too high for the layers to be annually deposited in turbid waters at depths of 40–70 m, indicating that the onset of the CIE in the Marlboro Clay likely took on the order of millennia, not years. Re-coring of Millville to minimize drilling disturbance and allow a higher resolution study of the carbon isotope excursion is highly desirable.

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Drilling disturbance and constraints on the onset of the Paleocene–Eocene boundary carbon isotope excursion in New Jersey

Climate of the Past ◽

10.5194/cp-11-95-2015 ◽

2015 ◽

Vol 11 (1) ◽

pp. 95-104 ◽

Cited By ~ 12

Author(s):

P. N. Pearson ◽

E. Thomas

Keyword(s):

New Jersey ◽

Carbon Isotope ◽

Supporting Evidence ◽

Drilling Mud ◽

Ocean Drilling Program ◽

Surface Ocean ◽

Turbid Waters ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

The Impact

Abstract. The onset of the Paleocene–Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE; approx. 56 Mya) was geologically abrupt, but it is debated whether it took thousands of years or was effectively instantaneous. Wright and Schaller (2013) published a significant new record of the onset of the CIE, and claimed that it could be resolved across 13 annual layers in a drill core through the Marlboro clay at Millville, New Jersey (Ocean Drilling Program (ODP) Leg 174X). Supporting evidence for similar layering was reported from another New Jersey drill site, Wilson Lake B, and a photograph of the Marlboro clay in outcrop (Wright and Schaller, 2014). Such a short duration would imply an instantaneous perturbation of the atmosphere and surface ocean and the impact of a comet or asteroid as the likely cause. However, Pearson and Nicholas (2014) suggested, based on the published core photographs, that the layers in the Marlboro clay cores could be artifacts of drilling disturbance, so-called biscuiting, wherein the formation is fractured into layers or biscuits and drilling mud is injected in between the layers. (We now prefer the term core discing following Kidd, 1978.) Here we report new observations on the cores which support that interpretation, including concentric grooves on the surfaces of the core discs caused by spinning in the bit, micro-fracturing at their edges, and injected drilling mud. We re-interpret the limited outcrop evidence as showing joints rather than sedimentary layers. We argue that foraminifer concentrations in the sediments are far too high for the layers to have been annually deposited in turbid waters at depths of 40–70 m, indicating that the onset of the CIE in the Marlboro clay likely took on the order of millennia, not years (Zeebe et al., 2014). Re-coring of Millville aimed at minimizing drilling disturbance to allow a higher-resolution study of the carbon isotope excursion is highly desirable.

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Onset of carbon isotope excursion at the Paleocene-Eocene thermal maximum took millennia, not 13 years

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1321177111 ◽

2014 ◽

Vol 111 (12) ◽

pp. E1062-E1063 ◽

Cited By ~ 24

Author(s):

R. E. Zeebe ◽

G. R. Dickens ◽

A. Ridgwell ◽

A. Sluijs ◽

E. Thomas

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Excursion ◽

Thermal Maximum

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Distortion of carbon isotope excursion in bulk soil organic matter during the Paleocene-Eocene thermal maximum

Geological Society of America Bulletin ◽

10.1130/b31389.1 ◽

2016 ◽

Vol 128 (9-10) ◽

pp. 1352-1366 ◽

Cited By ~ 18

Author(s):

Allison A. Baczynski ◽

Francesca A. McInerney ◽

Scott L. Wing ◽

Mary J. Kraus ◽

Paul E. Morse ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Carbon Isotope ◽

Bulk Soil ◽

Carbon Isotope Excursion ◽

Thermal Maximum

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Diagenetic Attenuation of Carbon Isotope Excursion Recorded by Planktic Foraminifers During the Paleocene-Eocene Thermal Maximum

Paleoceanography and Paleoclimatology ◽

10.1002/2017pa003314 ◽

2018 ◽

Vol 33 (4) ◽

pp. 367-380 ◽

Cited By ~ 9

Author(s):

Reinhard Kozdon ◽

D. Clay Kelly ◽

John W. Valley

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Excursion ◽

Thermal Maximum

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Record of Early Toarcian carbon cycle perturbations in a nearshore environment: the Bascharage section (easternmost Paris Basin)

Solid Earth Discussions ◽

10.5194/sed-6-1073-2014 ◽

2014 ◽

Vol 6 (1) ◽

pp. 1073-1100 ◽

Cited By ~ 4

Author(s):

M. Hermoso ◽

D. Delsate ◽

F. Baudin ◽

L. Le Callonnec ◽

F. Minoletti ◽

...

Keyword(s):

Isotopic Composition ◽

Carbon Isotope ◽

Isotopic Signature ◽

Oxygen Isotopic Composition ◽

Black Shales ◽

Positive Trend ◽

Oceanic Anoxic Event ◽

Carbon Isotope Excursion ◽

Oxygen Isotopic ◽

Global Nature

Abstract. In order to understand the significance of worldwide deposition of black shale facies in the Early Toarcian (~ 183 Ma), considerable attention has been drawn to this Early Jurassic sub-Stage over the last three decades. The discovery of a pronounced negative carbon isotope excursion (CIE) within the black shales disrupting the generally positive trend in carbon isotopes has stimulated many studies, particularly with a view to establish the local vs. global nature of this major geochemical phenomenon. Here we document the sedimentological and chemostratigraphic evolution of a proximal environment in the Luxembourgian sedimentary area, the so-called Gutland. At Bascharage, Lower Toarcian sediments record the isotopic signature of the Early Toarcian Oceanic Anoxic Event (OAE) by a pronounced positive trend that testifies for widespread anoxia. The expression of the carbon isotope perturbation in this section however, is unusual compared to adjacent NW European sections. A first −7 ‰ negative CIE, whose onset is recorded at the top of the tenuicostatum zone, can be assigned to the well-documented and potentially global T-CIE with confidence using the well-constrained ammonite biostratigraphic framework for this section. In this interval, facies contain only a limited amount of carbonate as a result of intense detrital supply in such a proximal and shallow environment. Stratigraphically higher in the section, the serpentinum zone records a subsequent CIE (−6 ‰) that is expressed by four negative steps, each being accompanied by positive shifts in the oxygen isotopic composition of carbonate. The preservation state of coccoliths and calcareous dinoflagellates in the second CIE is excellent and comparable to that observed in under- and overlying strata, so this cannot be an artefact of diagenesis. Considering the nature of this record, and the lack of such a pronounced event in the serpentinum zone in coeval sections in Europe, we hypothesise that this second CIE was caused by local factors. The geochemical record of carbonate with a relatively light carbon and relatively heavy oxygen isotopic composition is compatible with the so-called Küspert model, by which a CIE can be explained by an influx of 12C-rich and cold waters due to upwelling bottom water masses. With the ongoing effort of high-resolution studies of the Meso-Cenozoic eras, further CIEs are likely to be found, but it has to be remembered that their (global) significance can only be determined via an integrated sedimentological, mineralogical, micropalaeontological and geochemical approach.

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Capturing the global signature of surface ocean acidification during the Palaeocene–Eocene Thermal Maximum

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2017.0072 ◽

2018 ◽

Vol 376 (2130) ◽

pp. 20170072 ◽

Cited By ~ 7

Author(s):

Tali L. Babila ◽

Donald E. Penman ◽

Bärbel Hönisch ◽

D. Clay Kelly ◽

Timothy J. Bralower ◽

...

Keyword(s):

Ocean Acidification ◽

Carbon Isotope ◽

Atmospheric Carbon Dioxide ◽

Environmental Changes ◽

Planktonic Foraminifera ◽

Tight Coupling ◽

Carbonate Chemistry ◽

Surface Ocean ◽

Thermal Maximum ◽

Carbon Release

Geologically abrupt carbon perturbations such as the Palaeocene–Eocene Thermal Maximum (PETM, approx. 56 Ma) are the closest geological points of comparison to current anthropogenic carbon emissions. Associated with the rapid carbon release during this event are profound environmental changes in the oceans including warming, deoxygenation and acidification. To evaluate the global extent of surface ocean acidification during the PETM, we present a compilation of new and published surface ocean carbonate chemistry and pH reconstructions from various palaeoceanographic settings. We use boron to calcium ratios (B/Ca) and boron isotopes (δ 11 B) in surface- and thermocline-dwelling planktonic foraminifera to reconstruct ocean carbonate chemistry and pH. Our records exhibit a B/Ca reduction of 30–40% and a δ 11 B decline of 1.0–1.2‰ coeval with the carbon isotope excursion. The tight coupling between boron proxies and carbon isotope records is consistent with the interpretation that oceanic absorption of the carbon released at the onset of the PETM resulted in widespread surface ocean acidification. The remarkable similarity among records from different ocean regions suggests that the degree of ocean carbonate change was globally near uniform. We attribute the global extent of surface ocean acidification to elevated atmospheric carbon dioxide levels during the main phase of the PETM. This article is part of a discussion meeting issue ‘Hyperthermals: rapid and extreme global warming in our geological past’.

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