Paleogeographic and tectonic implications of quartzose sandstones of Barbados

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Abstract
The provenance of Paleogene sandstones on the island of Barbados is relevant to various models of the tectonic evolution of the southern Caribbean area. Modal point counts of 26 sandstones from Barbados show that the constituent grains most likely were derived from a composite craton interior and orogenic margin. Abundant detrital polycrystalline quartz grains have affinities to a spectrum of low‐ to high‐rank metamorphic/plutonic crystalline source rocks. Microprobe data suggest that feldspars were derived from metamorphic or plutonic source terrances. The complex heavy‐mineral suite of the terrigenous sandstones, including glaucophane, chloritoid, titanite, zircon, and aluminosilicates, supports derivation from orogenic and cratonal terranes. Due to the complex history of the South American‐Caribbean plate boundary and poor age constraints on timing of deposition, widely contrasting models have been proposed concerning the provenance of the sandstones. Convergence between the Aruba‐Orchila arc and continental South America during the Paleogene resulted in the formation of an E‐W trending foreland fold‐thrust belt and foredeep. Dominant sediment dispersal was to the east–northeast along tectonic strike. The present study shows that the terrigenous sandstones on Barbados probably were deposited in deep‐sea fans to the north of present‐day Araya Peninsula during and shortly after the late middle Eocene. Probable source terranes include the Guayana Shield, the Caribbean Mountain System/interior foreland fold‐thrust belt, and possibly (to a lesser extent) the Lesser Antilles magmatic arc or predecessor arc.