Deep-Sea Benthic Foraminifera and Their Biostratigraphic Potential: ABSTRACT

Abstract

Since the advent of the Deep Sea Drilling Project, late Mesozoic and Cenozoic benthic foraminifera have been recovered from cores drilled in the Indian, Pacific, and Atlantic Oceans. These faunas represent a broad range of low-middle latitude depositional environments from water depths of about 1,500 to 5,000 m. At the present time, analysis of fossil deep-sea benthic foraminifera is in a nascent stage. However, it is evident that many taxa occur in all the world's oceans, have easily recognized shell morphologies, and are generally more preservable than planktonic foraminifera. The major drawbacks to benthic species in biostratigraphic investigations are their long duration per species, compared to planktonic species, and the taxonomic confusion surrounding many taxa.In the Cretaceous there was little difference between deep ocean and continental slope faunas. Important stratigraphic markers, such as the Bolivinoides lineage, Bolivina incrassata, Gavelinella and Gyroidinoides species established in North America and Europe, were present in the deep ocean. Following a major evolutionary turnover in the early Paleogene, deep-sea faunas became less similar to those of continental margin as many new lower bathyal-abyssal genera evolved. Tertiary stratigraphic boundaries, including the top of the Paleocene, middle Eocene, top of the Eocene, upper Oligocene, and middle Miocene, are readily identifiable. After the middle Miocene, benthic foraminifera changed little and it is difficult to subdivide late Neogene faunas. End_of_Article - Last_Page 700------------