The paleozoic margin of North America in west Texas and Northern Mexico

Abstract

Analysis of gravity data from west Texas and northern Mexico delineates two large areas characterized by prominent, linear gravity highs. One feature corresponds to the Central Basin Platform of the Permian Basin, while the other corresponds to the Tascotal Uplift of the Big Bend area. Both features trend at high angles to the inferred early Paleozoic continental margin. A large mafic body is known to underlie the Central Basin Platform, while comparable gravity signatures over the Tascotal Uplift are also compatible with the presence of a large mafic body at depth. We interpret both the Central Basin Platform and the Tascotal Uplift as being related to reactivated mafic cores of failed or incipient rifts developed during establishment of the late Precambrian – early Paleozoic southern continental margin of North America.This reactivation during late Paleozoic compresional orogenic activity dominated the structural evolution of the region and must have greatly influenced sedimentation and marine circulation patterns in this area during the late Paleozoic.