Geochemical evidence for island-arc origin of the Villa de Cura Blueschist Belt, Venezuela

Abstract

New geochemical data from the Villa de Cura indicate that it is a subducted (and exhumed) island-arc terrane. The majority of the basalts are primitive island-arc tholeiites (44.8--51.5 wt% SiO2, 6.7--22.8 wt% MgO). REE and immobile trace element data from the Villa de Cura exhibit island-arc signatures, including (1) flat to LREE enriched REE patterns with La/Yb ratios of 1.23--6.03, and (2) enrichment of LILE relative to HFSE with a strongly negative Nb anomaly (La/Nb = 1.56--7.90). Thus, the Villa de Cura is similar to other Albian-Aptian age island arc tholeiites documented throughout the Caribbean. A model for formation and initial subduction of the Villa de Cura is presented. Correlation of the Villa de Cura with other allochthonous basalts in the Caribbean will help to constrain developing paleotectonic models of Caribbean