--> ABSTRACT: Tectonic and Sedimentary Evolution of Bransfield Basin, Antarctica, by J. D. Jeffers, M. A. Thomas, and John B. Anderson; #91030 (2010)

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Tectonic and Sedimentary Evolution of Bransfield Basin, Antarctica

J. D. Jeffers, M. A. Thomas, John B. Anderson

The Bransfield basin is the youngest and best developed of a series of extensional marginal basins on the Pacific margin of the Antarctic Peninsula. Marine geophysical data collected over five seasons show that the back arc is segmented laterally into three subbasins separated by transform zones. These subbasins differ in width, depth, structural style, and seismicity and are correlated with three different age segments of subducted sea floor. The distribution of principal sedimentary environments, identified from high-resolution seismic reflection data, and their associated lithofacies, seen in piston cores and surface sediment samples, is controlled largely by the tectonic segmentation of the basin. Terrigenous sediments prograde into the basin from the continent side, hereas sediment gravity-flow processes deliver volcaniclastic material from the arc to slope-base aprons and to fan lobes at the outlets of fiords. Organic-rich muds fill the deep basin; their proximity to submarine volcanic centers produces thermogenic hydrocarbons. Understanding the recent tectonic and sedimentary evolution of the Bransfield basin may help refine interpretations of the older deformed marginal basin sequences of southern South America, the Scotia Arc, and the Antarctic Peninsula.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.