Ultrabasic Rocks from the Cayman Trough, Caribbean Sea

Ultrabasic rocks have been dredged from the center of the Cayman Trough, a postulated boundary between the North American and Caribbean plates, 160 km southwest of Grand Cayman Island. Serpentinite, which may be altered spinel Iherzolite, dominates the collection and is believed to be bedrock in the station area. Two samples of a clinopyroxene-plagioclase-ilmenite crystal cumulate were found.