Holocene to Pleistocene Planktonic Foraminifera of Leg 15, Site 147 (Cariaco Basin [Trench], Caribbean Sea) and Their Climatic Interpretation

Abstract

The Pleistocene to Holocene planktonic foraminifera of Site 147 in the Cariaco Basin, off the north coast of eastern Venezuela, were investigated for their ecologic significance. Characteristic species and their frequency, are plotted and the results compared with curves by Emiliani (1966) and Ericson and Wollin (1968). Several warm-and cold-water intervals are distinguished. Site 147 falls into the upper part of the Globorotalia truncatulinoides truncatulinoides Zone (approxi-mately 320,000 years to Recent) and comprises from bottom to top the Pleistocene Globorotalia hessi (part only), Globigerina calida calida, Globigerina bermudezi and the Holocene Globoro-talia fimbriata subzones. This compares with zones V to Z of Ericson and Wollin (1968). Fifty-nine planktonic foraminiferal species and subspecies were distinguished, of which four are described as new. They are Globigerina clarkei n. sp., Globigerina megastoma cariacoensis n. ssp., Hastigerinella riedeli n. sp., and Globorotalia bermudezi n. sp. Neogloboquadrina blowi is introduced as a new name for Globigerina subcretacea Chapman. Variability and details of wall structures of the well-preserved planktonic foraminifera are illustrated by scanning electron micrographs. Abstract Introduction Hydrological Setting Paleoecological Investigations Working Method Ecology of characteristic planktonic foraminifera Observations on Site 147 Paleoclimatic Interpretation of Site 147 Climatic Zonation and Correlation Climatologic Zonation of Site 147 CONTENTS