HR: 17:00h
AN: GP54A-05    [Abstracts]
TI: Paleomagnetic Results From Cretaceous Arc Terranes in Central Hispaniola: Implications for the Paleogeography of the Caribbean Plate
AU: * Glaccum, K E
EM: glaccumk@yahoo.com
AF: Department of Earth Sciences, Florida International University, 11200 SW 8th Street, PC 344, Miami, FL 33199, United States
AU: Clement, B M
EM: clementb@fiu.edu
AF: Department of Earth Sciences, Florida International University, 11200 SW 8th Street, PC 344, Miami, FL 33199, United States
AU: Draper, G
EM: draper@fiu.edu
AF: Department of Earth Sciences, Florida International University, 11200 SW 8th Street, PC 344, Miami, FL 33199, United States
AB: Paleolatitude constraints on Cretaceous arc components are critical for testing kinematic models of the origin and evolution of the Caribbean plate. Rotational controls on lithospheric structures that comprise, or are adjacent to, the North American- Caribbean plate boundary zone reveal the complex tectonic mechanisms that have accommodated North American and Caribbean plate interactions. The general consensus among previous paleomagnetic work supports northward transport and anti-clockwise rotation for Greater Antilles arc terranes, yet the extent of displacement remains poorly constrained. We report new paleomagnetic results from the Lower Cretaceous Los Ranchos Formation and Upper Cretaceous Tireo Group arc volcanic and volcaniclastic rocks of the eastern and central cordillera of Hispaniola. A stable ChRM component carried by magnetite (unblocking temperatures 550-580° C) or hematite (650-675° C) was isolated in 6 sites. For the Tireo, 4 sites give a mean direction of D=320.7°, I=19.1°, k=98.3, α95=9.3° and yield a positive fold test. The site mean inclination implies a paleolatitude of 9.8° +5.3° / -4.9°. Comparison of the observed Tireo paleomagnetic pole against the 80 Ma North American reference pole indicates anti-clockwise vertical-axis rotation of 22.9° ± 9.1°, and northward transport of 10.9° ± 8.8°, with respect to the North American plate. The 2 remaining sites from the older Los Ranchos Formation significantly differ from the Tireo Group results, although insufficient sites for the Los Ranchos preclude the calculation of a mean direction. However, shallow inclinations and westerly declinations of the existing Los Ranchos data suggest near equatorial placement and additional anti-clockwise vertical-axis rotation.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 8150 Plate boundary: general (3040)
DE: 8157 Plate motions: past (3040)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting