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Miocene to present oceanographic variability in the Scotia Sea and Antarctic ice sheets dynamics: insight from revised seismic-stratigraphy following IODP Expedition 382

Citation

Perez, LF and Martos, YM and Garcia, M and Weber, ME and Raymo, ME and Williams, T and Bohoyo, F and Armbrecht, L and Bailey, I and Brachfeld, S and Gluder, A and Guitard, M and Gutjahr, M and Hemming, S and Hernandez-Almeida, I and Hoem, FS and Kato, Y and O'Connell, S and Peck, VL and Reilly, B and Ronge, TA and Tauxe, L and Warnock, J and Zheng, X, and the IODP Expedition 382 Scientists, Miocene to present oceanographic variability in the Scotia Sea and Antarctic ice sheets dynamics: insight from revised seismic-stratigraphy following IODP Expedition 382, Earth and Planetary Science Letters, 553 Article 116657. ISSN 0012-821X (2021) [Refereed Article]


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DOI: doi:10.1016/j.epsl.2020.116657

Abstract

Scotia Sea and the Drake Passage is key towards understanding the development of modern oceanic circulation patterns and their implications for ice sheet growth and decay. The sedimentary record of the southern Scotia Sea basins documents the regional tectonic, oceanographic and climatic evolution since the Eocene. However, a lack of accurate age estimations has prevented the calibration of the reconstructed history. The upper sedimentary record of the Scotia Sea was scientifically drilled for the first time in 2019 during International Ocean Discovery Program (IODP) Expedition 382, recovering sediments down to ∼643 and 676 m below sea floor in the Dove and Pirie basins respectively. Here, we report newly acquired high resolution physical properties data and the first accurate age constraints for the seismic sequences of the upper sedimentary record of the Scotia Sea to the late Miocene. The drilled record contains four basin-wide reflectors Reflector-c, -b, -a and -a' previously estimated to be ∼12.6 Ma, ∼6.4 Ma, ∼3.8 Ma and ∼2.6 Ma, respectively. By extrapolating our new Scotia Sea age model to previous morpho-structural and seismic-stratigraphic analyses of the wider region we found, however, that the four discontinuities drilled are much younger than previously thought. Reflector-c actually formed before 8.4 Ma, Reflector-b at ∼4.5/3.7 Ma, Reflector-a at ∼1.7 Ma, and Reflector-a' at ∼0.4 Ma. Our updated age model of these discontinuities has major implications for their correlation with regional tectonic, oceanographic and cryospheric events. According to our results, the outflow of Antarctic Bottom Water to northern latitudes controlled the Antarctic Circumpolar Current flow from late Miocene. Subsequent variability of the Antarctic ice sheets has influenced the oceanic circulation pattern linked to major global climatic changes during early Pliocene, Mid-Pleistocene and the Marine Isotope Stage 11.

Item Details

Item Type:Refereed Article
Keywords:Miocene, Scotia Sea, Antarctic ice sheet, seismic-stratigraphy, IODP Expedition 382
Research Division:Earth Sciences
Research Group:Geology
Research Field:Marine geoscience
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Antarctic and Southern Ocean ice dynamics
UTAS Author:Armbrecht, L (Dr Linda Armbrecht)
ID Code:147883
Year Published:2021
Web of Science® Times Cited:3
Deposited By:Ecology and Biodiversity
Deposited On:2021-11-20
Last Modified:2021-11-22
Downloads:0

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