DELINEATION OF THE PRECAMBRIAN HEREFORD BASIN: AN INTEGRATED GEOPHYSICAL STUDY OF AN ANCIENT BASIN WITHIN THE BASEMENT OF THE TEXAS PANHANDLE

The Palo Duro basin, in the Texas Panhandle, formed during the Paleozoic. However, drilling and geophysical studies have shown that this region is underlain by a complex Precambrian basement terrane. Specifically, the basement is part of the Southern Granite-Rhyolite Province that is mostly composed of layered volcanics. The tectonic history of this area included accretion of exotic terrains (1.8-1.6 Ga) to form continental crust, an extended episode of intracratonic magmatism (1.5-1.3 Ga) to form the western portion of the Southern Granite-Rhyolite Province, extension and mafic magmatism (1.1 Ga), burial by early Paleozoic marine sediments, late Paleozoic deformation to form the Ancestral Rockies, and subsequent stability. In our study, an integrated analysis of drilling, seismic reflection, and gravity data indicates that a Precambrian basin lies beneath the Palo Duro basin. This basin is named the Hereford basin after the nearby town of Hereford, Texas, and it is mostly filled with volcanics. The geometry of the Hereford basin suggests that this region experienced extension prior to 1.1 Ga. The Hereford basin appears to be an area of long-lived continental rifting, that is associated with three to four episodes of volcanism, with the resulting volcanics being interlayered with mafic sills.