CRUSTAL HISTORY OF MARGARITA ISLAND (VENEZUELA) IN DETAIL - CONSTRAINT ON THE CARIBBEAN PLATE-TECTONIC SCENARIO

The pressure-temperature-time-deformation evolution for the crust of M argarita Island (Venezuela) has been established to allow comparison w ith current plate-tectonic models for the Caribbean region, On Margari ta, the 12 recognizable stages of development can be summarized in ter ms of the following evolving tectonic settings: Protolith evolution as Aptian-Albian or older oceanic crust, as well as continental crust wi th Paleozoic basement (stages 1 and 2); accretion and high-pressure me tamorphism (500-600 degrees C, 10-14 kbar) as the Margarita Complex in the deep level of a fore are at 100-90 Ma (stage 3); ascent, cooling, and emplacement into the intermediate crustal level of a volcanic are at 90-80 Ma (stage 4); transform plate-margin setting at a comparable level at 80-50 Ma (stage 5); second episode of rapid uplift and cooli ng (stages 6 and 7); and shallow crustal level close to transform plat e margin from 50 Ma to present (stages 8 to 12). This complex sequence is in excellent agreement with plate-tectonic scenarios that require a Pacific origin for the Caribbean plate and eastward migration of the Margarita Complex and its correlatives along northern South America s ince the Cretaceous.