Paleogeography of the Caribbean Plate: Constraints from a Paleomagnetic Study of Cretaceous Arc Terranes in Central Hispaniola

Previous paleomagnetic work in the Caribbean generally suggests northward transport and anti-clockwise rotation for Greater Antilles arc terranes. Large uncertainties in several of the previous studies, however means that the magnitude of this 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 either by magnetite or hematite was isolated in six sites. For the Tireo Group, four sites give a mean direction of D=320.7°, I=19.1°, k=98.3, alpha-95=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 Goup paleomagnetic pole with the 80 Ma North American reference pole indicates an 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 two sites from the older Los Ranchos Formation yield results that differ significantly from the Tireo Group results. Although there are insufficient sites from the Los Ranchos Formation to calculate a mean direction, shallow inclinations and westerly declinations of the available data suggest near equatorial paleolatitudes and additional anti-clockwise vertical-axis rotation.