Eocene Thermal Maximum 2

Eocene Thermal Maximum 2 (ETM-2), also called H-1 or Elmo (Eocene Layer of Mysterious Origin), was a transient period of global warming that occurred around 54 Ma.[1][2] [3][4][5] It was the second major hyperthermal that punctuated long-term warming from the Late Paleocene through the Early Eocene (58 to 50 Ma).[6]

The hyperthermals were geologically brief time intervals (<200,000 years) of global warming and massive input of isotopically light carbon into the ocean and atmosphere.[7][8] The most extreme and best-studied event, the Paleocene-Eocene Thermal Maximum (PETM or ETM-1), occurred about 1.8 million years before ETM-2, at approximately 55.8 Ma. Other hyperthermals likely followed ETM-2 at nominally 53.6 Ma (H-2), 53.3 (I-1), 53.2 (I-2) and 52.8 Ma (informally called K, X or ETM-3). The number, nomenclature, absolute ages and relative global impact of the Eocene hyperthermals are the source of much current research.[9][10] In any case, the hyperthermals appear to have ushered in the Early Eocene Climatic Optimum, the warmest sustained interval of the Cenozoic Era.[11] They also definitely precede the Azolla event at about 49 Ma.

  1. ^ Westerhold, Thomas; Röhl, Ursula; Laskar, Jacques; Raffi, Isabella; Bowles, Julie; Laurens, Lucas J.; Zachos, James C. (6 April 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 and Paleoclimatology. 22 (2). Bibcode:2007PalOc..22.2201W. doi:10.1029/2006PA001322.
  2. ^ Galeotti, Simone; Sprovieri, Mario; Rio, Domenico; Moretti, Matteo; Francescone, Federica; Sabatino, Nadia; Fornaciari, Eliana; Giusberti, Luca; Lanci, Luca (1 August 2019). "Stratigraphy of early to middle Eocene hyperthermals from Possagno (Southern Alps, Italy) and comparison with global carbon isotope records". Palaeogeography, Palaeoclimatology, Palaeoecology. 527: 39–52. Bibcode:2019PPP...527...39G. doi:10.1016/j.palaeo.2019.04.027. S2CID 149669059. Retrieved 4 December 2022.
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  4. ^ Nicolo, M.J.; Dickens, G.R.; Hollis, C.J.; Zachos, J.C. (2007). "Multiple early Eocene hyperthermals: Their sedimentary expression on the New Zealand continental margin and in the deep sea". Geology. 35 (8): 699–702. Bibcode:2007Geo....35..699N. doi:10.1130/G23648A.1.
  5. ^ Stap, L.; Lourens, L.J.; Thomas, E.; Sluijs, A.; Bohaty, S.; Zachos, J.C. (2010). "High-resolution deep-sea carbon and oxygen isotope records of Eocene Thermal Maximum 2 and H2". Geology. 38 (7): 607–610. Bibcode:2010Geo....38..607S. doi:10.1130/G30777.1. hdl:1874/385773. S2CID 41123449.
  6. ^ Zachos, J.C.; Dickens, G.R.; Zeebe, R.E. (2008). "An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics". Nature. 451 (7176): 279–283. Bibcode:2008Natur.451..279Z. doi:10.1038/nature06588. PMID 18202643.
  7. ^ Li, Yuanji; Sun, Pingchang; Falcon-Lang, Howard J.; Liu, Zhaojun; Zhang, Baoyong; Zhang, Qiang; Wang, Junxian; Xu, Yinbo (15 January 2023). "Eocene hyperthermal events drove episodes of vegetation turnover in the Fushun Basin, northeast China: Evidence from a palaeoclimate analysis of palynological assemblages". Palaeogeography, Palaeoclimatology, Palaeoecology. 610: 111317. Bibcode:2023PPP...61011317L. doi:10.1016/j.palaeo.2022.111317. Retrieved 3 December 2022 – via Elsevier Science Direct.
  8. ^ Sluijs, A.; Schouten, S.; Donders, T.H.; Schoon. P.L.; Röhl, U.; Reichart, G.-J.; Sangiorgi, F.; Kim, J.-H.; Sinninghe Damsté, J.S.; Brinkhuis, H. (2009). "Warm and wet conditions in the Arctic region during Eocene Thermal Maximum 2". Nature Geoscience. 2 (11): 777–780. Bibcode:2009NatGe...2..777S. doi:10.1038/ngeo668. hdl:1874/39397. S2CID 130137472.
  9. ^ Slotnick, B.S.; Dickens. G.R.; Nicolo, M.J.; Hollis, C.J.; Crampton, J.S.; Zachos, J.C.; Sluijs, A. (2012). "Large amplitude variations in carbon cycling and terrestrial weathering during the latest Paleocene and earliest Eocene: The record at Mead Stream, New Zealand". Journal of Geology. 120 (5): 487–505. Bibcode:2012JG....120..487S. doi:10.1086/666743. hdl:1911/88269. S2CID 55327247.
  10. ^ Abels, H.A..; Clyde, H.C.; Gingerich, P.D.; Hilgen, F.J.; Fricke, H.C.; Bowen, G.J.; Lourens, L.J. (2012). "Terrestrial carbon isotope excursions and biotic change during Palaeogene hyperthermals". Nature Geoscience. 5 (8): 326–329. Bibcode:2012NatGe...5..326A. doi:10.1038/NGEO1427.
  11. ^ Slotnick, B. S.; Dickens, G. R.; Hollis, C. J.; Crampton, J. S.; Strong, C. Percy; Phillips, A. (17 September 2015). "The onset of the Early Eocene Climatic Optimum at Branch Stream, Clarence River valley, New Zealand". New Zealand Journal of Geology and Geophysics. 58 (3): 262–280. Bibcode:2015NZJGG..58..262S. doi:10.1080/00288306.2015.1063514. S2CID 130982094.