East Antarctic ice sheet fluctuations during the middle Miocene climatic transition inferred from faunal and biogeochemical data on planktonic Foraminifera (ODP Hole 747A, Kerguelen Plateau)

Online Access: Get full text
doi: 10.3133/of2007-1047.srp037
Author(s): Verducci, M.; Foresi, L. M.; Scott, G. H.; Tiepolo, M.; Sprovieri, M.; Lirer, F.
International Symposium on Antarctic Earth Sciences
Author Affiliation(s): Primary:
University of Siena, Department of Earth Sciences, Siena, Italy
GNS Science, New Zealand
Consiglio Nazionale delle Ricerche, Italy
Volume Title: Antarctica; a keystone in a changing world; online proceedings for the Tenth international symposium on Antarctic earth sciences
Volume Author(s): Cooper, Alan, editor; Raymond, Carol
Source: Open-File Report - U. S. Geological Survey, No.OF2007-1047; Tenth international symposium on Antarctic earth sciences; Antarctica; a keystone in a changing world, Santa Barbara, CA, Aug. 26-Sept. 1, 2007, edited by Alan Cooper and Carol Raymond; International Symposium on Antarctic Earth Sciences. Publisher: U. S. Geological Survey, Reston, VA, United States. ISSN: 0196-1497 CODEN: XGROAG
Note: In English. 24 refs.; illus.
Summary: Regarding 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.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Antarctic ice sheet; Antarctica; Biochemistry; Biostratigraphy; Calcium; Cenozoic; East Antarctic ice sheet; Foraminifera; Geochemistry; Invertebrata; Isotope ratios; Isotopes; Kerguelen Plateau; Leg 120; Magnesium; Metals; Mg/Ca; Microfossils; Middle Miocene; Miocene; Neogene; O-18/O-16; ODP Site 747; Ocean Drilling Program; Oxygen; Paleoclimatology; Protista; Southern Ocean; Stable isotopes; Tertiary; USGS
Coordinates: S544841 S544840 E0764739 E0764738
Record ID: 2007120394
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.