PALEOFLOW HISTORY DETERMINED FROM MUDWAVE MIGRATION - ARGENTINE BASIN

A mudwave site in the central Argentine Basin was investigated to dete rmine its present and past mudwave activity. Site 7, on the south flan k of the Ewing Drift in the northern Argentine Basin, has mudwaves tha t have migrated primarily through preferential deposition, resulting i n a relatively complete sediment on both wave flanks. Thus a history o f mudwave migration can be determined for this site. The mudwave studi ed shows migration from before 420 ka until 32 ka, with paleocurrent s peeds near 15 cm s-1 and with minor changes in current speeds around 1 10-120 ka. The wave migration rate became less from 32 ka to 26 ka wit h paleospeeds of 9 cm s-1. Wave migration ceased about 26 ka, suggesti ng a cessation in flow. This study indicates that bottom water velocit ies at this site were high during the last glacial period, but dropped abruptly near the end of the last glacial period. However, bottom cur rent velocities appear to have been moderately high during the previou s interglacial period (approximately 120 ka), suggesting that there is no simple relationship between flow speed and paleoclimate at this si te.