Sites 642, 643, and 644 were investigated for planktonic foraminifers. Frequent occurrences of barren intervals caused by dissolution as well as low-diversity and long-ranging assemblages reduce the stratigraphic resolution of these records. Based on Neogloboquadrina species a local zonation, correlated with high-latitude North Atlantic schemes, is proposed for the middle Miocene to Quaternary and correlated with paleomagnetic records.The middle to late Miocene boundary is defined by the last appearance datum of Neogloboquadrina mayeri and the first appearance datum of Neogloboquadrina acostaensis. Late Miocene age is defined by a N. acostaensis zone, whereas latest Miocene to Pliocene zones are defined by dextral and sinistrally coiling Neogloboquadrina atlantica. The top of the Pliocene is characterized by dextral and sinistrally coiling Neogloboquadrina pachyderma. The Pleistocene is defined by a nearly monospecific assemblage of Neogloquadrina pachy derma in its sinistrally coiled and encrusted variety.
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