HARRIS, P. M. and W. S. KOWALIK, Chevron Petroleum Technology Company, La Habra, CA; and A. J. LOMANDO, Chevron Overseas Petroleum Inc., San Ramon, CA

ABSTRACT: Structural Control of Carbonate Platform Configuration and Depositional Environment Distribution--Caicos Platform, B. W. I. and Chinchorro Bank, Offshore Yucatan

High quality Landsat TM images of two extant carbonate platforms reveal a relationship between suspected underlying structure, platform configuration, and the distribution of depositional environments. We propose that the nature of the relationships identified here suggests a more common control by structure of carbonate platform development than is commonly considered.

The Caicos Platform, British West Indies, illustrates control over platform configuration by a regional north- and northeast-trending fault system. The faults, previously unrecognized, are interpreted from the Landsat images on the basis of linear platform edges, i.e. a scalloped platform margin likely due to platform-margin collapse, and linear internal boundaries that affect the modern bathymetry and sedimentation. We relate: (a) the width of the back-reef lagoon, (b) the location of platform interior patch reefs, and (c) the position of tidal channels to faults that cut across the Pleistocene-Holocene islands of the northern rim of the platform.

Chinchorro Bank, offshore Yucatan is an elongate carbonate platform (45 km x 17 km) oriented north-northeast with both external and internal platform configuration controlled and/or influenced by faults. Long, straight segments of the platform margin are controlled by a set of north-northeast bounding faults on the windward and leeward sides. Faults parallel to this trend within the platform control the position of an elongate platform interior lagoon, a central ridge and island, and the boundaries of sand and patch reef trends. In the southern, deeper water portion of the platform, a northeast trending fault system controls major changes in bathymetry and the orientation of the platform interior patch reef trend which forms an elongate barrier-like structure.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.