Late Quaternary benthic foraminifera of the Venezuela Basin

Abstract

A suite of 122 species and varieties of benthic foraminifera is recorded from eight late Quaternary cores raised from water depths of about 4000 m in the central Venezuela Basin. The influence of the North Atlantic Deep Water (NADW) on the Holocene assemblage is reflected in the dominance of Cibicides wuellerstorfi, particularly in the core from near the Jungfern sill. The other common or abundant Holocene (Ericson zone Z) species in these cores include Melonis pompilioides, Nuttallides umbonifera, and Pullenia sp. Dominant species that are distinctive of the uppermost Pleistocene part (zone Y) of the cores include Massilina sp., Cassidulina subglobosa, and Nummoloculina irregularis. Eponides tumidulus shows erratic stratigraphic distribution, but attains a peak at or above the Y–Z boundary (13,000 yrs B.P.). Principal components analyses of assemblage compositions also demonstrate a significant faunal change at this boundary. Overall, these Quaternary benthic foraminiferal distribution trends are significantly different from those in the adjacent Grenada Basin, in part because of the absence of Bulimina aculeata and Uvigerina peregrina. The preservation records of the planktonic foraminifera and Pteropoda indicate that the Venezuela Basin bottom water was less corrosive in the latest Pleistocene than it is today.