Tectonic synthesis, Deep Sea Drilling Project Leg 78A: structural evolution of offscraped and underthrust sediment, northern Barbados Ridge complex.

Abstract

Indicates offscraping of approximately the upper 200m of the incoming sediment section and underthrusting of the subjacent sediment with the ocean crust. Approximately lithostatic fluid pressure was measured in a thrust fault splaying off the decollement separating the offscraped and underthrust sediment packages; this high fluid pressure apparently allows the underthrusting of the coherent sedimentary sequence beneath the decollement. The underthrust sedimentary section is principally pelagic in character. Thrust and reverse faulting and the decollement tend to develop in or adjacent to underconsolidated Miocene smectitic clays, indicating stratigraphic control on faulting.-from Authors