La estructura del Cinturón de Maimón en la isla de Hispaniola y sus implicaciones geodinámicas

Abstract

The Median belt of central Hispaniola is composed of several NW-trending sub-belts, composed of basalt, serpentinized Loma Caribe peridotite and the greenschist-grade, meta-volcanic Maimón belt. The southwestern margin of the Maimón belt, below the thrust contact with the peridotite, contains an approximately 3 km thick shear zone composed of mylonitic and phyllonitic schists whose kinematic indicators demonstrate N to NNE-directed thrust sense of motion. Penetrative deformation produced by the emplacement decreases progressively to the northeast and affects the Neocomian rocks of the Los Ranchos Formation. We suggest that this deformation was produced by the thrust obduction of the peridotite. Upper Albian-Cenomanian limestones that unconformably overlie the Los Ranchos are not penetratively deformed, thus indicating that both the deformation and obduction took place in Aptian-Albian times. As this event took place before the eruption of the adjacent basalts, we suggest that the Median belt ophiolite consists of the association of the Duarte complex meta-basalts and the Loma Caribe peridotite. The obduction of the Duarte-Loma Caribe ophiolite coincides with changes in the chemistry of the Hispaniola are magmas. We suggest that both phenomena are related to a previously proposed subduction polarity reversal event.