Large-Scale Patterns of Recent Sedimentation Along the Cayman Trough Pull-Apart Basin, Caribbean Sea: ABSTRACT

Abstract

The North American-Caribbean plate boundary zone consists of a broad zone of active strike-slip deformation that extends 3,200 km from Middle America to the Lesser Antilles. An 1,100-km-long, 100-km-wide pull-apart basin the Cayman Trough is the dominant structural element of the submerged central part of the plate boundary zone between Jamaica and Honduras. In order to investigate large-scale patterns of recent sedimentation in a fully marine pull-apart setting, the authors surveyed a 90,000-km{sup 2} area along the southern edge of the Cayman Trough using SeaMARC II side-scan sonar, 3.5 KHz, and digital single-channel reflection techniques. These data allow them to divide the southern margin of the Cayman Trough pull-apart into three provinces of recent sedimentation: (1) an eastern terrigenous province characterized by straight short canyon systems (average 1-3 km wide and 10-15 km long) and associated small, lobate fans; canyon-fan systems are sourced by clastic spillover from filled borderland-type basins and by erosion of emergent fault-block islands; (2) a central carbonate province characterized by periplatform carbonate detritus fringing four isolated carbonate banks which collectively make up the Nicaraguan Rise; canyon systems (1-3 km wide, 15-80 km long) are highly meandering when unfaulted and straight when faulted; and (3) an easternmore » carbonate and terrigenous province characterized by both carbonate sediments shed off the easternmost bank of the Nicaraguan Rise bank and by terrigenous sediment derived from Jamaica.« less