Paleocene–Eocene Thermal Maximum
The Paleocene–Eocene thermal maximum (PETM), alternatively ”Eocene thermal maximum 1 (ETM1)“ and formerly known as the "Initial Eocene" or “Late Paleocene thermal maximum", was a geologically brief time interval characterized by a 5–8 °C (9–14 °F) global average temperature rise and massive input of carbon into the ocean and atmosphere.[1][2] The event began, now formally codified, at the precise time boundary between the Paleocene and Eocene geological epochs.[3] The exact age and duration of the PETM remain uncertain, but it occurred around 55.8 million years ago (Ma) and lasted about 200 thousand years (Ka).[4][5]
The PETM arguably represents our best past analogue for which to understand how global warming and the carbon cycle operate in a greenhouse world.[2][6][7] The time interval is marked by a prominent negative excursion in carbon stable isotope (δ13C) records from around the globe; more specifically, a large decrease in the 13C/12C ratio of marine and terrestrial carbonates and organic carbon has been found and correlated across hundreds of locations.[2][8][9] The magnitude and timing of the PETM (δ13C) excursion, which attest to the massive past carbon release to our ocean and atmosphere, and the source of this carbon remain topics of considerable current geoscience research.
What has become clear over the last few decades is that Stratigraphic sections across the PETM reveal numerous changes beyond warming and carbon emission.[2] Consistent with an Epoch boundary, fossil records of many organisms show major turnovers. In the marine realm, a mass extinction of benthic foraminifera, a global expansion of subtropical dinoflagellates, and an appearance of excursion taxa, including within planktic foraminifera and calcareous nannofossils, all occurred during the beginning stages of the PETM. On land, many modern mammal orders (including primates) suddenly appear in Europe and in North America.[10]
Paleogene graphical timeline | ||||||||
−70 — – −65 — – −60 — – −55 — – −50 — – −45 — – −40 — – −35 — – −30 — – −25 — – −20 — | MZ Danian Selandian Thanetian Ypresian Lutetian Bartonian Priabonian Rupelian Chattian |
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Subdivision of the Paleogene according to the ICS, as of 2023.[12] Vertical axis scale: Millions of years ago | ||||||||
- ^ Haynes LL, Hönisch B (14 September 2020). "The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum". Proceedings of the National Academy of Sciences of the United States of America. 117 (39): 24088–24095. Bibcode:2020PNAS..11724088H. doi:10.1073/pnas.2003197117. PMC 7533689. PMID 32929018.
- ^ a b c d McInerney FA, Wing SL (30 May 2011). "The Paleocene-Eocene Thermal Maximum: A Perturbation of Carbon Cycle, Climate, and Biosphere with Implications for the Future". Annual Review of Earth and Planetary Sciences. 39 (1): 489–516. Bibcode:2011AREPS..39..489M. doi:10.1146/annurev-earth-040610-133431.
- ^ Westerhold T, Röhl U, Raffi I, Fornaciari E, Monechi S, Reale V, Bowles J, Evans HF (February 2008). "Astronomical calibration of the Paleocene time". Palaeogeography, Palaeoclimatology, Palaeoecology. 257 (4): 377–403. Bibcode:2008PPP...257..377W. doi:10.1016/j.palaeo.2007.09.016.
- ^ Bowen GJ, Maibauer BJ, Kraus MJ, Röhl U, Westerhold T, Steimke A, Gingerich PD, Wing SL, Clyde WC (2015). "Two massive, rapid releases of carbon during the onset of the Palaeocene–Eocene thermal maximum". Nature. 8 (1): 44–47. Bibcode:2015NatGe...8...44B. doi:10.1038/ngeo2316.
- ^ Li M, Bralower TJ, Kump LR, Self-Trail JM, Zachos JC, Rush WD, Robinson MM (2022-09-24). "Astrochronology of the Paleocene-Eocene Thermal Maximum on the Atlantic Coastal Plain". Nature Communications. 13 (1): 5618. Bibcode:2022NatCo..13.5618L. doi:10.1038/s41467-022-33390-x. PMC 9509358. PMID 36153313.
- ^ Gutjahr M, Ridgwell A, Sexton PF, Anagnostou E, Pearson PN, Pälike H, Norris RD, Thomas E, Foster GL (August 2017). "Very large release of mostly volcanic carbon during the Palaeocene–Eocene Thermal Maximum". Nature. 548 (7669): 573–577. Bibcode:2017Natur.548..573G. doi:10.1038/nature23646. PMC 5582631. PMID 28858305.
- ^ Jones S, Hoggett M, Greene S, Jones T (2019). "Large Igneous Province thermogenic greenhouse gas flux could have initiated Paleocene-Eocene Thermal Maximum climate change". Nature Communications. 10 (1): 5547. Bibcode:2019NatCo..10.5547J. doi:10.1038/s41467-019-12957-1. PMC 6895149. PMID 31804460.
- ^ Kennett JP, Stott LD (September 1991). "Abrupt deep-sea warming, palaeoceanographic changes and benthic extinctions at the end of the Palaeocene". Nature. 353 (6341): 225–229. Bibcode:1991Natur.353..225K. doi:10.1038/353225a0.
- ^ Koch PL, Zachos JC, Gingerich PD (1992). "Correlation between isotope records in marine and continental carbon reservoirs near the Palaeocene/Eocene boundary". Nature. 358 (6384): 319–322. Bibcode:1992Natur.358..319K. doi:10.1038/358319a0. hdl:2027.42/62634.
- ^ Van der Meulen B, Gingerich PD, Lourens LJ, Meijer N, Van Broekhuizen S, Van Ginneken S, Abels HA (15 March 2020). "Carbon isotope and mammal recovery from extreme greenhouse warming at the Paleocene–Eocene boundary in astronomically-calibrated fluvial strata, Bighorn Basin, Wyoming, USA". Earth and Planetary Science Letters. 534 116044. Bibcode:2020E&PSL.53416044V. doi:10.1016/j.epsl.2019.116044.
- ^ Zachos, J. C., Kump, L. R. (2005). "Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene". Global and Planetary Change. 47 (1): 51–66. Bibcode:2005GPC....47...51Z. doi:10.1016/j.gloplacha.2005.01.001.
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved December 16, 2024.