The Rio San Juan complex includes the largest exposed area of Cretaceous basement rocks exposed in the North Coast Zone of Hispaniola. The Hicotea, Puerca Gorda, and El Guineal schists were metamorphosed in a Late Cretaceous subduction zone where they were protruded at depth first by the Jagua Clara melange and later by the Arroyo Sabana melange. Serpentinite protrusion also occurred during the Paleocene-Lower Eocene, and when some of these protrusions breached the surface. The southern part of the complex was formed either in the Hispaniola magmatic arc or by intrusion of fore-arc gabbroic magmas into fore-arc basement represented by the Cuaba amphibolites. The southern area was juxtaposed against the northern area before the Paleocene. Exposure of the assembled complex has occurred by the Eocene, but the complex was probably covered by clastic sediments during Late Eocene to Miocene times. Both the Cretaceous subduction complex and the mid-Tertiary clastic cover were disrupted and deformed by Neogene, east-west-trending, sinistral, transcurrent movements. -from Authors
