Eocene Thermal Maximum 3
Eocene Thermal Maximum 3 (ETM3), also known as the K or X event, was a hyperthermal event that occurred during the middle of the Ypresian stage of the Eocene epoch.
Timing
ETM3 has been dated to about 52.5 Ma.{{Cite journal |last1=Agnini |first1=Claudia |last2=Macrì |first2=Patrizia |last3=Backman |first3=Jan |last4=Brinkhuis |first4=Henk |last5=Fornaciari |first5=Eliana |last6=Giusberti |first6=Luca |last7=Luciani |first7=Valeria |last8=Rio |first8=Domenico |last9=Sluijs |first9=Appy |last10=Speranza |first10=Fabio |date=14 May 2009 |title=An early Eocene carbon cycle perturbation at ~52.5 Ma in the Southern Alps: Chronology and biotic response |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008PA001649 |journal=Paleoceanography and Paleoclimatology |language=en |volume=24 |issue=2 |doi=10.1029/2008PA001649 |bibcode=2009PalOc..24.2209A |hdl=1874/385799 |issn=0883-8305 |access-date=11 March 2025 |via=Wiley Online Library|hdl-access=free }} It is demarcated in the chronostratigraphic record by a marked negative δ13C and δ18O excursion.{{cite book |last1=Frontalini |first1=Fabrizio |last2=Coccioni |first2=Rodolfo |last3=Catanzariti |first3=Rita |last4=Jovane |first4=Luigi |last5=Savian |first5=Jairo F. |last6=Sprovieri |first6=Mario |editor-last1=Menichetti |editor-first1=Marco |editor-last2=Coccioni |editor-first2=Rodolfo |editor-last3=Montanari |editor-first3=Alessandro |date=1 July 2016 |title=The Stratigraphic Record of Gubbio: Integrated Stratigraphy of the Late Cretaceous–Paleogene Umbria-Marche Pelagic Basin |url=https://pubs.geoscienceworld.org/gsa/books/edited-volume/697/The-Stratigraphic-Record-of-Gubbio-Integrated |chapter=The Eocene Thermal Maximum 3: Reading the environmental perturbations at Gubbio (Italy) |chapter-url=https://pubs.geoscienceworld.org/gsa/books/edited-volume/697/chapter-abstract/3808696/The-Eocene-Thermal-Maximum-3-Reading-the?redirectedFrom=fulltext |publisher=Geological Society of America |doi=10.1130/2016.2524(11) |isbn=9780813725246}}
Causes
ETM3 was caused by a massive input of isotopically light carbon into the atmosphere. It has been suggested that methane hydrate reservoirs, recharged over millennia after melting during previous Eocene hyperthermals, were the source of this light carbon during ETM3.{{Cite journal |last1=Westerhold |first1=Thomas |last2=Röhl |first2=Ursula |last3=Donner |first3=B. |last4=Zachos |first4=James C. |date=22 May 2018 |title=Global Extent of Early Eocene Hyperthermal Events: A New Pacific Benthic Foraminiferal Isotope Record From Shatsky Rise (ODP Site 1209) |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017PA003306 |journal=Paleoceanography and Paleoclimatology |language=en |volume=33 |issue=6 |pages=626–642 |doi=10.1029/2017PA003306 |bibcode=2018PaPa...33..626W |issn=2572-4517 |access-date=11 March 2025 |via=Wiley Online Library}}
Effects
ETM3, in conjunction with the other hyperthermal events of the Early Eocene, led to the onset of the Early Eocene Climatic Optimum (EECO), the warmest long-term climatic interval of the Cenozoic.{{cite journal |last1=Slotnick |first1=B. S. |last2=Dickens |first2=G. R. |last3=Hollis |first3=C. J. |last4=Crampton |first4=J. S. |last5=Strong |first5=C. Percy |last6=Phillips |first6=A. |date=17 September 2015 |title=The onset of the Early Eocene Climatic Optimum at Branch Stream, Clarence River valley, New Zealand |journal=New Zealand Journal of Geology and Geophysics |volume=58 |issue=3 |pages=262–280 |bibcode=2015NZJGG..58..262S |doi=10.1080/00288306.2015.1063514 |s2cid=130982094 |doi-access=free}} The diversity of benthic foraminifera decreased in the southeastern Atlantic Ocean during ETM3.{{Cite journal |last1=Thomas |first1=Ellen |last2=Boscolo-Galazzo |first2=Flavia |last3=Balestra |first3=Barbara |last4=Monechi |first4=Simonetta |last5=Donner |first5=Barbara |last6=Röhl |first6=Ursula |date=1 July 2018 |title=Early Eocene Thermal Maximum 3: Biotic Response at Walvis Ridge (SE Atlantic Ocean) |url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018PA003375 |journal=Paleoceanography and Paleoclimatology |language=en |volume=33 |issue=8 |pages=862–883 |doi=10.1029/2018PA003375 |bibcode=2018PaPa...33..862T |issn=2572-4517 |access-date=11 March 2025 |via=Wiley Online Library|url-access=subscription }}
See also
References
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