Annotated record of the detailed examination of Mn deposits from DSDP Leg 22 (Sites 212, 213, 215, 216, 217, 217A)

Eight sites were drilled on Leg 22 in the northeastern Indian Ocean. Three sites (214, 216, 217) on Ninetyeast Ridge penetrated a thick sequence of mostly Tertiary calcareous oozes passing down into shallow-water sediments with volcanogenic material in Sites 214 and 216. The age of the basal sequence increases northwards from Paleocene (214) through Maastrichtian (216) to Campanian (217). A nonmarine sequence of volcanoclastics and lignite overlies basalt at 214. Drilling terminated in a dolomite chert sequence at 217 before bsalt was encountered. Two sites (213, 215), in deep water on either side of Ninetyeast Ridge, showed calcareous ooze of Paleocene to early Eocene age overlying basalt passing up into brown clay and finally siliceous ooze of late Miocene and younger age. A major hiatus centered in the Oligocene occurs at both these sites. One site (212), drilled in the deepest part of the Wharton Basin, penetrated a brown clay sequence interbedded with several thick calcareous units, each of a very short time duration. Evidence from sedimentary structures and calcareous microfossils.