Stratigraphic and Petrochemical Data Support Subduction Polarity Reversal of the Cretaceous Caribbean Island Arc

Abstract

Stratigraphic and petrochemical data from island arc rocks in the NE Caribbean support previously proposed tectonic models of attempted subduction of the Caribbean oceanic plateau beneath the Caribbean island arc during pre-Aptian time (~119 Ma) and consequent reversal of arc polarity from SW-facing to NE-facing by the early Late Cretaceous (~97 Ma). We propose that reversal in subduction polarity is marked by an abrupt change from relatively depleted and non-radiogenic tholeiites of the primitive island arc series to more enriched and radiogenic volcanic rocks of the calc-alkaline series. The stratigraphic contact between the primitive island arc series and the overlying calc-alkaline series in central and eastern Hispaniola (Dominican Republic) and Puerto Rico is a major unconformity overlain by a shallow-marine limestone of Aptian-Albian age. We compare the characteristics of the proposed pre-Aptian Caribbean subduction reversal event to the better-documented Neogene subduction reversal event in the Solomon island arc in the SW Pacific.