1. Miocene to present oceanographic variability in the Scotia Sea and Antarctic ice sheets dynamics: Insight from revised seismic-stratigraphy following IODP Expedition 382
- Author
-
Maureen E. Raymo, Sidney R. Hemming, Thomas A Ronge, Marcus Gutjahr, Yuji Kato, Anna Glüder, Iodp Expedition Scientists, Fernando Bohoyo, Suzanne O'Connell, Iván Hernández-Almeida, Jonathan P. Warnock, Trevor Williams, Ian Bailey, Lara F. Pérez, Brendan T Reilly, Lisa Tauxe, Michael E Weber, Yasmina M. Martos, Stefanie Ann Brachfeld, Victoria L Peck, Linda Armbrecht, Michelle Guitard, Xufeng Zheng, Marga García, and Frida S. Hoem
- Subjects
Geochemistry & Geophysics ,ncore-log-seismic correlation ,010504 meteorology & atmospheric sciences ,Antarctic ice sheet ,Late Miocene ,010502 geochemistry & geophysics ,01 natural sciences ,core-log-seismic correlation ,Scotia Sea ,sheets evolutio ,Marine Isotope Stage 11 ,Paleontology ,Drake Passage ,IODP Expedition 382 ,oceanic gateways ,Antarctic ice sheets evolution ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Antarctic ice ,14. Life underwater ,Life Below Water ,0105 earth and related environmental sciences ,geography ,GB ,geography.geographical_feature_category ,International Ocean Discovery Program ,Tectonics ,Geophysics ,Antarctic Bottom Water ,13. Climate action ,Space and Planetary Science ,Physical Sciences ,Earth Sciences ,Sedimentary rock ,Ice sheet ,Geology - Abstract
Highlights • Core-log-seismic correlation allows to assign ages to the Scotia Sea seismic record. • Major implications are derived on the relation between regional and global events. • The main stratigraphic events are much younger than previously proposed. • Three major phases for the regional oceanography are observed from late Miocene. • These phases appear to be closely linked to the Antarctic Ice Sheet dynamics. 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.
- Published
- 2021
- Full Text
- View/download PDF