Abstract

Considerable quantities of reworked planktonic foraminifers have been discovered in certain horizons of a Late Pleistocene and a Late Holocene shallow nearshore marine sedimentary unit in southwest Mississippi and in eastern New Orleans, Louisiana, respectively Three species, Heterohelix reussi , Globigerinelloides bentonensis and Rugoglobigerina ( Rugoglobigerina ) reicheli pustulata make up the faunas with one additional species, represented by one specimen. Heavy mineral analyses confirm the assumption that the fossils have been eroded by lateral fluvial erosion from lower Upper Cretaceous formations, probably in the Dallas-Sherman area, northern Texas, as well as adjacent Oklahoma and Arkansas areas. They were transported by the Red and Mississippi Rivers over distances of about 1,200-2,400 km. The fact that these assemblages seemingly remained undiluted in the suspended river sediments during their long but fast journey and stayed together until reburial, suggests that transport took place mostly in suspension and the fine-very fine sand-sized foraminifer tests were not incorporated into the bedload. The few benthonic foraminifers found may have been carried by currents up the continental shelf slope before incorporation into the described sediments.

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