Texas

The dominant structural feature of the Panhandle gas field of Texas is the Amarillo-Wichita uplift, a northwest-trending geanticline, extending over 200 miles from the Wichita Mountains of southern Oklahoma to the Dalhart basin northwest of Amarillo, Texas.

As a result of uplift that began during Late Mississippian or Early Pennsylvanian time the Pre-Pennsylvanian rocks were eroded and the Precambrian basement complex of the Amarillo- Wichita area was exposed. By Early Permian time the Precambrian rocks were submerged and marine rocks were deposited over the uplift.

Repeated crustal movement since that time has folded and faulted the rocks that overlie the uplift.

The rocks of the Panhandle field that have been studied as part of this investigation range from Upper Pennsylvanian to Lower Permian and include "arkose," shallow marine limestone and dolomite, and siltstone and shale interbedded with anhydrite.

The Panhandle gas field originally contained the largest commercial helium reserve in the United States. It also contains anomalous concentrations of radon. The reservoir rocks contain from 2 to 4 ppm (parts per million) of uranium. The uranium content of crude oil peripheral to the gas field ranges from less than 1 to 300 parts per billion. The uranium content of the brine is from less than 0.1 to about 10 ppb.

Early investigations by the U.S. Bureau of Mines have shown that the western part of the Panhandle field contains one of the largest helium reserves in the United States.

The discovery (by J. W. Hill, U.S. Geological Survey) of anomalous concentrations of radon- 222, an intermediate product in the decay of uranium, in the gases suggested that a significant fraction of the helium might have been derived from uranium.