HR: 0830h
AN: T11B-01
TI: Regional Effects of Oblique Collision of the Bahamas Platform in the Hispaniola-Puerto Rico area
AU: * Mann, P
EM: paulm@ig.utexas.edu
AF: Inst. for Geophysics Univ. of Texas at Austin, 4412 Spicewood Springs Rd., Austin, TX 78759 United States
AU: Grindlay, N R
AF: Center for Marine Science Univ. of North Carolina Wilmington, One Marvin K. Moss Lane, Wilmington, NC 28409 United States
AU: van Gestel, J
AF: BP Exploration, 2203 S. Gessner, Houston, TX 77063 United States
AU: Dolan, J F
AF: Dept. of Earth Sciences Univ. of Southern California, University Park, Los Angeles, CA 90089 United States

AB: We interpret marine geophysical data in the Puerto Rico-Hispaniola area in terms of a Late Miocene to Recent oblique collision between the Bahama Platform, one of the thickest carbonate platforms in the world, and the Caribbean plate in Hispaniola. Oblique collision and indentation of the northeastern Caribbean plate margin in Hispaniola by the Bahama platform has slowed the rate of oblique subduction beneath northeastern Hispaniola, reoriented GPS-observed motions in Hispaniola to more easterly directions, and thrust the Hispaniola area southwestward relative to the Caribbean plate. Separation of a collided, detached, relatively slower moving Hispaniola area from the relatively faster moving, uncollided, rigid Caribbean plate in areas east of Hispaniola has produced post-Early Pliocene rifting in the marine strait between Hispaniola and Puerto Rico (Mona Passage). Southwest-verging folds and northeast-dipping thrust faults affecting clastic sedimentary rocks of Plio-Pleistocene age in the intermontane ramp basins of central Hispaniola and the large, active accretionary prism of the western and central Muertos trench are attributed to backthrusts formed as the Hispaniola area is pushed southwestward over the Caribbean plate by the colliding Bahama platform. Collision-related deformation across Puerto Rico and the Virgin Islands consists of a large roughly east-west trending arch defined by folding of a Oligocene-early Pliocene carbonate platform. Roughly east-west fault scarps seen on the seafloor and onland areas of western Puerto Rico appear to be dip-slip or oblique-slip deformation associated with post-early Pliocene arch formation.

DE: 8105 Continental margins and sedimentary basins
DE: 8107 Continental neotectonics
DE: 8123 Dynamics, seismotectonics
SC: T
MN: Fall Meeting 2000