ABSTRACT: The Kerguelen Plateau: A Frontier Too Far?

WISE, SHERWOOD W., Jr., Florida State University, Tallahassee, FL, MILLARD F. COFFIN, University of Texas Geophysics Institute, Austin, TX, and JACK R. ENGLISH, STEPHANIE D. GATHMAN, and PETER H. WILKINSON, Texaco, Inc., Bellaire, TX

The submergent Kerguelen Plateau, one of the largest and most remote of the oceanic igneous plateaus, formed about 114-110 Ma in the southern Indian Ocean. It presently lies between 45 degrees and 63 degrees S, equidistant from South Africa and southwest Australia. Two major sedimentary basins at water depths between 500 and 2000 m on the northern and southern sectors of the plateau contain up to 3000 m of Mesozoic and Cenozoic sediments.

Ocean Drilling Program Site 750 on the eastern margin of the southern (Raggatt) basin cored lower Albian, kaolinite-rich fluvial sediments with large wood fragments indicative of a relatively warm, humid, and well-forested environment; organic contents range up to 7%. Foundering of the plateau occurred by Cenomanian times, but portions remained close to shelf depths throughout the Cretaceous, and over 400 m of glauconite-rich sediments with organic contents of 0.2-1.0% accumulated in the western Raggatt Basin (Site 748). During the Campanian-Maestrichtian, a bryozoa-rich bioclastic facies developed on the basin flank and large bioherms formed toward the basin center. Faulting during the Maestrichtian shed debris from uplifted basement blocks at ODP Site 747 north of the Raggatt Basin, and the entire plateau subsided, resulting in predominantly pelagic sedimentation during the Cenozoic.

Burial history models suggest that hydrocarbons could have been generated in both basins. Albian to Cenomanian source rocks are present, and the Campanian-Maestrichtian bioherms represent excellent reservoir rocks; however, suitable cap rocks have not been detected. This factor, plus the harsh present-day weather conditions, remoteness of the plateau, and deep water depths make the Kerguelen Plateau a challenging exploration frontier.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)