Neogene paleomagnetism and oroclinal bending of the central Andes of Bolivia

Abstract

Geophysical and tectonic evidence suggests that the principal vertical axis bending of the Bolivian Orocline is a late Cenozoic event related to subduction and Andean uplift. To further test this hypothesis, paleomagnetic data are presented from Miocene basins within the Altiplano and Cordillera Oriental of Bolivia, located in the presumed southern limb of the orocline. Although the paleomagnetic data could represent independent mesoscale block rotations, the preferred interpretation is that they confirm the hypothesis that a significant portion of the oroclinal bending occurred during the late Cenozoic. Using the unit mean paleomagnetic declinations in the well-dated sections, minimum rates of oroclinal bending during the late Cenozoic are calculated to range from 0.6°/m.y. to 1.7°/m.y. -from Authors