Core-based reconstruction of paleoenvironmental conditions in the southern Drake Passage (West Antarctica) over the last 150 ka |
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Authors: | Ho Il Yoon Kyu-Cheul Yoo Young-Suk Bak Yong Il Lee Jae Il Lee |
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Institution: | (1) Korea Ocean Research and Development Institute, Korea Polar Research Institute, Songdo TP, Incheon, 406-840, Republic of Korea;(2) School of Earth and Environmental Sciences, Seoul National University, Seoul, 151-747, Republic of Korea;(3) Department of Earth and Environmental Sciences, Chonbuk National University, Jeonju, 561-751, Republic of Korea |
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Abstract: | A deep-sea sediment core (GC98-06) from the southernmost Drake Passage, West Antarctica, shows late Quaternary depositional
environments distinctly different from sedimentary drifts commonly found along the southwestern Pacific margin of the Drake
Passage. The chronology of the core has been inferred using geochemical tracers of paleoproductivity and diatom biostratigraphy,
and represents the paleoceanographic conditions in a continental rise setting during the last 150,000 years. Three dominant
sediment types associated with distinct sedimentary processes have been identified using textural/compositional analyses:
(1) hemipelagic mud (interglacial sediments) deposited from pelagic settling of bioclasts, meltwater plumes, and ice-rafted
detritus; (2) terrigenous mud (glacial sediments) delivered by turbid meltwater plumes; and (3) massive muds marking the boundaries
from interglacial to glacial periods. The succession of the sedimentary facies in core GC98-06 is interpreted to reflect temporal
changes in environmental conditions prevailing on the continental rise of the southern Drake Passage in the course of successive
climatic stages over the last 150 ka: from the bottom upward, these are glacial, interglacial, glaciation, glacial, and interglacial
episodes. Variability in sediment flux and diatom abundance seem to have been related to changes in glacial advance, sea-ice
extent, and specific sedimentary environments, collectively influenced by mid- to late Quaternary climatic changes. |
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