Paleomagnetism of the Talpa de Allende and Mascota grabens, western Mexico: a preliminary report

Abstract

The Jalisco Block of Western Mexico is thought to be undergoing internal deformation associated with its proposed NW translation relative to the North American plate. This deformation has resulted in the formation of several graben structures within the northern portion of the Jalisco Block. An analysis of paleomagnetic data collected at six distinct, recent, lava flows fail to indicate any statistically significant (95% confidence level) motions in this area. However, the flattening parameter associated with the mean direction of these six sites (12.8°±13.1°), along with the close proximity of both the North American reference pole and the expected field direction at the sites to the corresponding 95% confidence cones of the palaeomagnetic results, indicates that additional data may allow for the resolution of the proposed northward movement of the Jalisco Block or of local tilting associated with faulting. -from Authors