Correlation of Continental-Margin and Deep-Sea Sequences--Neogene Examples from Pacific: ABSTRACT

Abstract

The Deep Sea Drilling Project (DSDP) has produced fundamental advances in Cenozoic planktonic biostratigraphy and our understanding of the Cenozoic paleo-oceanographic and paleoclimatic history of the world ocean. These new insights and data serve to increase the precision and resolution of provincial biostratigraphies and correlations commonly applied to continental-margin sequences, and thus result in more accurate reconstructions of margin histories. DSDP-IPOD Legs 18, 19, 31, 57, and 63 included drill sites close to tectonically active continental margins surrounding the North Pacific. They provide clear examples of correlation of deep-sea and epicontinental marine deposits in Mexico, California, Japan, and Korea. In particular, DSDP Site 173 off northern California h s yielded an important lower Miocene through Pleistocene (N4-N22) reference section, demonstrating the usefulness of DSDP data for interpretation of margin biostratigraphic, sedimentologic, and tectonic events on a regional scale. Multiple siliceous and calcareous plankton zones within this sequence provide an average biostratigraphic resolution of 0.5 m.y. with paleo-oceanographically induced biofacies trends marking zones of special value for interbasin correlation across latitude. Many of the planktonic datums and biofacies trends clearly defined in the thin (320 m), but nearly complete, Neogene column at DSDP Site 173 can be readily recognized in the thick paleoenvironmentally diverse and structurally disordered, continental-margin deposits now exposed along the Pacific Coast of Nort America. These correlations provide a framework for calibrating provincial biostratigraphic units; estimating rates of sediment accumulation, subsidence, and uplift in margin sequences; and hindcasting periods of increased primary productivity, variations in the oxygen-minimum layer, and deposition of sediments favorable for hydrocarbon generation. End_of_Article - Last_Page 473------------