Bathymetry and Sediment Geometry of the Greater Antilles Outer Ridge and Vicinity: Discussion and Reply.

摘要

Mattson suggests the uninterrupted existence of the Puerto Rico Trench as a physiographic feature since albian time, even though a major reorientation from north-south to east-west convergence between the Caribbean and North Atlantic lithosphere occurred in the Early Tertiary. Our analysis of marine geological and geophysical data shows the probable absence of a topographic trough between the eastern Greater Antilles and the Greater Antilles Outer Ridge during the middle Eocene, so that the Antilles were a direct source of epiclastic detritus carried by turbidity currents to form the stratified layer under the outer ridge. The absence of an intervening trough may be best explained by sediment infilling, possibly assisted by crustal rebound coincident with the Early Tertiary plate reorientation. A sharp cutoff in deposition of the stratified layer, extensive faulting of the layer on the north slope of the trench, and Upper Paleogene and Neogene shallow-water limestones presently situated deep along the south slope all attest to re-establishment of a topographic trough after the middle Eocene and extensive Tertiary development of the present Puerto Rico Trench.