The present-day motions of the Caribbean Plate

Abstract

Data pertaining to the instantaneous relative motions of the Caribbean plate with respect to the North American and Cocos plates have been inverted by using the iterative fitting algorithm formulated by Minster et al. (1974). The best-fitting Caribbean-North American pole is located at 50°N ± 18°, 116°E ± 9°, and the computed angular rate is 0.20° ± 0.07°/m.y., which corresponds to a spreading rate of 2.1 cm/yr across the mid-Cayman rise. The model predicts that the present-day motion of South America with respect to the Caribbean is northwestward and suggests that since the late Tertiary this motion has been accommodated along an en echelon series of northwest-trending right lateral strike-slip faults and northeast-trending thrust faults which occupy a broad zone of deformation extending from the Curaçao Ridge and its westward extension into the South Caribbean Basin to the frontal thrusts along the southern boundary of the Venezuelan Coast Ranges. The model predicts that the relative motion between the Caribbean and Nazca plates is parallel to the continental margin south of the Gulf of Panama. The rate of motion of the Caribbean plate with respect to the mesosphere, deduced from the fixed hot spot hypothesis, is very small, and this plate may in fact be stationary over the mantle.