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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 3. (March)

First Page: 467

Last Page: 467

Title: Flow of Bottom Water Out of Weddell Sea, Antarctica--700,000 Years to Present: ABSTRACT

Author(s): Claudia L. Hokanson, John B. Anderson

Article Type: Meeting abstract


Bottom water produced at the Antarctic continental margin (loosely defined here as Antarctic bottom water, AABW) is thought to exert an important influence on calcium carbonate dissolution and terrigenous sedimentation in basins of the world ocean. Indeed it has been suggested that variation in AABW production and flow causes significant seafloor scouring in the Southern Hemisphere ocean basins. Today, most AABW flowing into the world ocean originates in the Weddell Sea. Piston cores from this vital region taken in the path of proposed present-day bottom-water flow, have been subjected to micropaleontologic, geochemical, and size analyses and their Th230 and paleomagnetic stratigraphy determined. These data have been used to reconstruct the history of AABW prod ction and flow in the Weddell Sea during the past 700,000 years.

Variations in standard deviation ranging from 1.473 to 2.339, with sediments laminated and nonlaminated respectively, indicate fluctuations in apparent bottom-water-flow velocity and possibly, in turn, production in the west-central Weddell Sea. These fluctuations between peak and low velocities have occurred over periods of more than 100,000 years. Periods of peak-flow velocity also correspond to times when the calcite compensation depth (CCD) was elevated. Only in the past 300,000 years has the level of the CCD fallen below 4,000 m. Not yet fully understood is what seems to be a more rapid and chaotic periodicity in flow in the northwestern Weddell Sea and an apparent correlation between fluctuations and ice-rafted detritus (IRD). It does, however, seem apparent that during the past 700,000 years bottom-water flow in the Weddell Sea has not been strong enough to cause scouring.

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