Global Classification of Spectrum of Submarine Fan Types

Donn S. Gorsline

There is a pressing need for a schema in which we can arrange the variety of fan forms, both modern and ancient. Such schemes have been generated for the delta depositional form, the beach form, and to some extent for aeolian, fluvial, and glacial deposits. Work by several workers has demonstrated that three necessary dimensions define the variety of submarine fan morphological responses: (1) fan size, (2) sediment supply rate, and (3) the proportion of sand and mud in that supply. These three dimensions form a space within which all submarine fans can be fitted and within which four subspaces can be defined on the basis of order-of-magnitude changes in all three dimensions. Fan morphologies in the less than 10 km scale are simple cones or lobes (suprafan lobes); those of the order of 10 to 100 km may have both lobe and leveed channel components; those in the size range from 100 to 1,000 km tend to be dominated by channel systems and are probably composites of smaller fans analogous to crevasse splay systems in very large deltas. Fans larger than about 1,000 km are few in number (giant fans) and are dominated by large-scale channels. Megaturbidites are probably limited to systems of the third zone by the constraints of sediment supply and receiving area.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.