Bohaty, Steven M.; Zachos, James C. (2003): Significant Southern Ocean warming event in the late middle Eocene. Geological Society of America (GSA), Boulder, CO, United States, Geology (Boulder), 31 (11), 1017-1020, georefid:2003-083434

Abstract:
A prominent middle Eocene warming event is identified in Southern Ocean deep-sea cores, indicating that long-term cooling through the middle and late Eocene was not monotonic. At sites on Maud Rise and the Kerguelen Plateau, a distinct negative shift in delta (super 18) O values ( approximately 1.0ppm) is observed ca. 41.5 Ma. This excursion is interpreted as primarily a temperature signal, with a transient warming of 4 degrees C over 600 k.y. affecting both surface and middle-bathyal deep waters in the Indian-Atlantic region of the Southern Ocean. This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene-Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO (sub 2) levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan Orogen or increased ridge/arc volcanism during the late middle Eocene.
Coverage:
West: 1.1218 East: 82.4715 North: -58.2627 South: -65.0938
Relations:
Expedition: 113
Site: 113-689
Site: 113-690
Expedition: 119
Site: 119-738
Site: 119-744
Expedition: 120
Site: 120-748
Supplemental Information:
With GSA Data Repository Item 2003148
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G19800.1 (c.f. for more detailed metadata)
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