Seismic Stratigraphy of Giant Mass Movements on Actual Margins

Francis Coumes

Recent geophysical surveys of different marine slopes show distinct figures corresponding to sliding, slumping, and creeping processes.

The comparison of these phenomena is made on the basis of a seismic interpretation of gravity events in distinct margins and basins such as Indian Ocean, China Sea, Tasman Sea, and Mediterranean Sea.

The distinction between such phenomena is sometimes difficult, but some features seem characteristic of a slow movement of the sedimentary cover on low-angle slopes. This distinction is important, considering the reservoir potential of the sedimentary cover involved in the phenomena. In instantaneous events such as sliding, the successive processes following this first step lead in a final stage to a potential reservoir (such as the Bouma sequence). However, slow mass movement on slopes destroys the internal structure to finalize into chaotic or "transparent" layers that can be misinterpreted as sedimentary reservoirs.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.