Eastern Indian Ocean Cretaceous and Paleogene quantitative biostratigraphy

Abstract

During ODP Leg 121 holes were drilled at seven sites, on a transect across Broken Ridge and along Ninetyeast Ridge. The four Broken Ridge sites recovered a Turonian to holocene composite section according to environmental and tectonic history. The three Ninetyeast Ridge sites samples a Late Cretaceous to Tertiary paleoenvironmental transect and a record of hot-spot volcanism. CaCO3 content, weight percent >40-μm residue content, and weight distribution of the size fractions were recorded for all samples from all sites. Species distribution was determined quantitatively for two fractions. The number of >125-μm planktonic foraminifers per gram dry sediment and the percentage of >250-μm planktonic foraminifers of the >125-μm fauna were calculated. The description of Morozovella variospira (Belford, 1984) is emended, based on observations of material from middle Paleocene sediments from Site 758 on northern Ninetyeast Ridge. -from Authors