Reworked and Redeposited Larger Foraminifers on Slopes and in Basins of the Bahamas, Leg 101

Abstract

Larger shallow-water benthic foraminifers, along with planktonic foraminifers and calcareous nannofossils, oc­ curred in turbidites and debris flows of the slopes and basins of the Bahamas. Studies of larger foraminifers can in­ crease our understanding of platform flanks and their response to fluctuations in sea level, one of the main objectives of Leg 101. Some of these late Campanian to Pleistocene larger foraminifers were redeposited; others were reworked. These larger foraminifers lived in water depths of less than 130 m in the back- and fore-reef environments of Florida and the Bahamas. They were deposited in slopes and basins by turbidite and debris flow mechanisms. Larger foramini­ fers were absent on the upper slope but were present on the lower part of the slope and in the basin. The Paleoecology of these foraminifers permits reconstruction of the source area of the redeposited platform material in the turbidites and debris flows. The allochthonous larger foraminifers are found mostly in the Pleistocene, Pliocene, middle and lower Miocene, Oligocene, and Campanian. The occurrence of redeposited larger foraminifers seems to be linked to changes in sea level, while the occurrence of reworked larger foraminifers in the middle Miocene and Campanian appears related to tectonic events.