Oblique collision and accretion of the Netherlands Leeward Antilles to South America

Abstract

Accretion of the Netherlands Leeward Antilles volcanic island arc to northern South America (offshore Venezuela) was accompanied by deformation and clockwise block rotation. Structural analysis of Aruba, Curaçao, and Bonaire indicates that they were deformed during at least one ductile event (D1) and three brittle events (F1 - F3). The first deformation phase (D1 and F1) began in the Early Cretaceous, at approximately 110 Ma. Deformation features are consistent with displacement partitioning at the obliquely convergent Caribbean-Atlantic (proto-Caribbean) plate boundary. This deformation was accompanied by an approximate 90° clockwise rotation of the forearc terrane. The onset of the second phase of deformation (F2) occurred in the Eocene (∼55 Ma), also accompanied by a small amount of rotation, and structures are consistent with wrench tectonics in a pull-apart regime. This coincided with the collision of the Caribbean plate with the Great Bahama Bank and the initiation of convergence between North and South America. The youngest deformation structures and rotation (F3) are also associated with wrench faulting. Likely, motion along the Oca fault and the Caribbean plate transform fault initiated a major restraining bend in the late Paleogene. Beginning ∼12 Ma, the northeastward escape of the Maracaibo block further increased the complexity of tectonism at the Caribbean-South American plate boundary. Deformation structures are consistent with a total of 135° clockwise rotation of the Leeward Antilles islands and regional diachronous deformation from west to east since the Early Cretaceous. Copyright 2007 by the American Geophysical Union.