Crustal History and Plate Tectonic Development in the Southern Caribbean

摘要

Metamorphosed Aptian-Albian oceanic crust, Paleozoic continental basement and Cretaceous sediments form the basement of NE Venezuela. The pressure-temperature-deformation-time evolution of this crustal complex has been established as follows: accretion and common high-pressure meta-morphism in a fore-arc (100 ±10 Ma); ascent, cooling and emplacement into the intermediate crustal level of a volcanic arc (90-80 Ma); a transform plate - margin setting (80-50 Ma); a second episode of rapid uplift and cooling (50 Ma); a shallow crustal level close to a transform plate - margin (50 Ma to present). This complex evolutionary sequence agrees well with plate-tectonic scenarios restricting collision, accretion and high-reassure metamorphism to the western margin of South America, followed by passive eastward migration of large slivers of this crust along the northern margin since the Late Cretaceous; it does not support models proposing in situ collision with high-pressure metamorphism along the northern margin itself.