The vertical temperature gradient and carbon isotope signature of the deep sea during the ‘X-event’ and onset of the Early Eocene Climatic Optimum – preliminary results from ODP site 1262

The vertical temperature gradient and carbon isotope signature of the deep sea during the ‘X-event’ and onset of the Early Eocene Climatic Optimum – preliminary results from ODP site 1262

Polling, M.

Molengraaff Fonds

2011

The early Eocene (59-52 Ma) is a period in which Earth’s climate underwent gradual warming that was interrupted by several transient extreme warming events termed ‘hyperthermals’. The major hyperthermals ‐ the PETM (~55.5 Ma) and the ETM2 (~53.6 Ma) – are accompanied By 4-8ºC warming, massive release of 13C depleted carbon into the ocean-atmosphere system and carbonate dissolution. Along these two major climate perturbations a whole range of smaller possible hyperthermals (termed A to L) is identified or which much less is known. In tis study, a high-resolution carbon and oxygen isotope record is created across the early Eocene (~52 Ma) sediments of ODP site 1262. Several climatic perturbations are identified of which the so-called ‘X-event’ (or K, ETM3; 5224 Ma), with a negative excursion of 0.8‰ and0.5‰ in δ13C and δ18O respectively, is the most prominent. Moreover, shortly after the X-event another very brief (~40 kyr) perturbation is found with 0.7‰ And 0.6‰ negative excursions in δ13C and δ18O respectively at 52.15 Ma that is termed ‘X1’. Two more of such isotopic excursions are recognized and subsequently termed ‘X2’ and ‘X3’. One of these most probably represents event ‘L’ of Cramer et al., (2003). As such this study provides a high-resolution early Eocene climatic history, which will be used in future studies to determine the deep-sea temperature gradient during these possible ‘hyperthermal’ events.

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Utrecht University

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