11. FORAMINIFERS AND COARSE DETRITUS FROM FIVE DEEP-WATER SITES, DEEP SEA

Five sites of Leg 86 of the Deep Sea Drilling Project were drilled in water greater than 5000 m deep in the northwest Pacific. The objectives of the coring program at these sites included sampling Cenozoic pelagic sediments, in an effort to define paleoceanographic patterns and boundaries, and assessing the nature of the red clay/chert boundary which is seismically mappable. The biostratigraphy of foraminifers contributes to these objectives in only four short intervals. Cenozoic pelagic sediments contained rare, small, moderately preserved assemblages of planktonic foraminifers. Cal-careous sediments below 55.3 m sub-bottom at Site 576 are turbidites of Cretaceous age containing Santonian/Cam-panian foraminifers. A small assemblage of early Eocene age (P9-P11) was found at 163.28 m at Site 578, corroborat-ing a similar determination based on ichthyoliths. Foraminifers in calcareous sediment immediately above the chert at 176.44 m sub-bottom at Site 578 indicate a Campanian minimum for the age of the chert horizon at that location. At Site 580, a modest assemblage of late Pleistocene (N23) age was recovered above 41.29 m sub-bottom and an early Pleis-tocene (N22) assemblage found in one sample at 44.89 m sub-bottom. Samples from Sites 579 and 581 were barren of foraminifers. Examination of the washed residue for foraminifers disclosed abundant volcanic glass, Mn-oxide nodules and tubes, and eolian silt in the greenish and red pelagic clays. Biosiliceous debris and ichthyoliths are also common to abundant. Middle Miocene deposits at Site 581 contain ice-rafted basalt and andesite pebbles