Summary

During the earliest phase of sea level rise in a glacioeustatic cycle, limited accommodation space on the shelf, and the rapid shoreline transgression associated with massive deglaciation created a framework within which deltaic deposition was confined to a narrow zone at the shelf-edge. The relatively steeply reclined shelf-to-slope transition surface provided the sole depositional environment offering sufficient accommodation space for the development of substantial deltaic clinoforms. A mostly emergent continental shelf during this phase of shelf margin deposition precluded the generation of winter-chilled shelf water in the northern Gulf of Mexico. Early-rise stage shelf-edge deltas were therefore, swept year-round by the tropical Gulf Loop Current. Importantly, for explorationists, the warm waters of these early-rise stage deltas were home to distinctive calcareous bank - turtle grass flat benthic foraminiferal fauna, which spread from south Florida across the northern Gulf during the deglacial portion of each glacioeustatic cycle. In wells with detailed micropaleontological reports, the recorded presence of this unique fauna has provided a reliable means of recognizing the position of the lowstand shelf-to-slope transition.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah