East Antarctic Ice Sheet fluctuations during the Middle Miocene Climatic Transition inferred from faunal and biogeochemical data on planktonic foraminifera (Kerguelen Plateau)

This research focuses on a detailed study of faunal and biogeochemical changes that occurred at ODP Hole 747A in the Kerguelen Plateau region of the Southern Ocean during the middle Miocene (14.8-11.8 Ma). Abundance fluctuations of several planktonic foraminiferal taxa, stable oxygen isotope and Mg/...

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Bibliographic Details
Main Authors: VERDUCCI, M., FORESI, L. M., SCOTT, G. H., TIEPOLO, M., SPROVIERI, M., LIRER, F.
Other Authors: Cooper A., Raymond C., ISAES Editorial Team, Verducci, M., Foresi, L. M., Scott, G. H., Tiepolo, M., Sprovieri, M., Lirer, F.
Format: Conference Object
Language:English
Published: Alan Cooper, Carol Raymond, and the ISAES Editoria 2007
Subjects:
Antarctica
Kerguellen Plateau
Middle Miocene
planktonic foraminifera
Mg/Ca
biogeochemistry
Antarctic
Southern Ocean
Kerguelen
East Antarctic Ice Sheet
Antarc*
Ice Sheet
Planktonic foraminifera
Online Access:http://hdl.handle.net/11365/40648
https://doi.org/10.3133/of2007-1047
Description
Summary:This research focuses on a detailed study of faunal and biogeochemical changes that occurred at ODP Hole 747A in the Kerguelen Plateau region of the Southern Ocean during the middle Miocene (14.8-11.8 Ma). Abundance fluctuations of several planktonic foraminiferal taxa, stable oxygen isotope and Mg/Ca ratios have been integrated as a multi-proxy approach to reach a better understanding of the growth modality and fluctuations of the East Antarctic Ice Sheet (EAIS) during this period. A 7°C decrease in Sea Surface Temperature (SST), an abrupt turnover in the planktonic foraminiferal assemblage, a 1.5‰ shift towards heavier δ18O values (Mi3 event) and a related shift towards heavier seawater δ18O values between 13.9 and 13.7 Ma, are interpreted to reflect rapid surface water cooling and EAIS expansion. Hole 747A data suggest a major change in the variability of the climate system fostered by EAIS expansion between 13.9 and 13.7 Ma. Ice sheet fluctuations were greater during the interval 14.8-13.9 Ma compared with those from 13.7 to 11.8 Ma, whereas the latter interval was characterized by a more stable EAIS. In our opinion, the middle Miocene ice sheet expansion in Antarctica represents a first step towards the development of the modern permanent ice sheet.

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