Since the beginning of the Deep Sea Drilling Project (DSDP) in 1968 and extending through 1975, organic geochemical studies have been undertaken on about 2300 samples recovered on Legs 1 through 44 from sediments beneath the ocean floors. These studies have provided fundamental information regarding the distribution of carbon in oceanic sediments and have yielded a better understanding of the processes that alter and transform organic matter in the marine environment.
Beginning with Leg 38 organic geochemists have been included as members of the scientific staffs of those legs of particular organic geochemical interest. They have advised operations personnel on matters concerning potential hazards, such as drilling into significant accumulations of oil and gas, and have collected samples for the scientific community. The shipboard organic geochemical laboratory is equipped with sophisticated instrumentation to provide those meassurements helpful in advising the drilling operation
Since Leg 15, samples for organic geochemical studies have been maintained at -18°C at the DSDP sample repository at the Scripps Institution of Oceanography, La Jolla, California. Samples are distributed to the scientific community, but at least one quarter of all cores is retained for possible future studies.
Organic geochemical studies generally relate to one of these topic areas: (1) petroleum potential/source rock evaluation, (2) thermal history and gradients, (3) diagenesis, (4) gas hydrates, (5) novel geochemical fossils, (6) sources of organic materials, (7) paleo-depositional environments, and (8) geochronology.
Much of the organic geochemical work on hydrocarbons and kerogen has been directed to the potential of sediments as sources of petroleum. The organic matter found thus far during drilling is dominantly of terrestrial origin and thermally immature, but much of the organic matter could be a potential source of petroleum (mainly gas) if buried more deeply.
Three new technologies will help advance organic geochemical knowledge of ocean sediments: (1) pressure core barrel for evaluation of gas hydrates, (2) hydraulic piston core to study in detail sources and early diagenesis of organic matter, and (3) riser for the study of late diagenesis and catagenesis.
Figures & Tables
At the present the Glomar Challenger has drilled over 500 holes over the world ocean, involving hundreds of scientists from dozens of countries. This volume is intended as a review of some of theimportant results from the most comprehensive, ambitious and successful earth-bound geologic project ever undertaken. The symposium upon which this volume originated was held April 4, 1979 at the SEPM/AAPG Annual Meeting in Houston. No comprehensive synthesis of all aspects of the DSDP has appeared, and the topic coverage in this volume is biased towards the sediments and fossils, and their significance for certain aspects of earth history – paleogeography, bathymetry, climatology, oceanography, ecology, environments – all in keeping with the audience of sedimentary geologists.