T163 Combining Geophysics and Geology: The George P. Woollard Award Session

Tuesday, 2 November 2010
8:00 AM - 12:00 PM
Mile High Ballroom 2AB/3AB

LINEAMENTS OF SOUTHERN HIGH PLAINS: POSSIBLE INDICATORS OF RECENT FAULTING

Paper number: T163-12
Program: Technical Sessions
Time: 10:35 AM – 10:50 AM

Authors

Abstract

Through the analysis of topographic data, we have identified a number of parallel lineaments trending approximately N37°E across the Southern High Plains (SHP) of Texas. Although some of these lineaments appear to serve as drainage, they trend roughly perpendicular to the down slope direction of the SHP and the larger streams in the region. The source of formation of these lineaments is not known, however they appear across the entire SHP in the areas south of the Matador arch.

This abstract will focus on a portion of two lineaments in Northern Hockley County, Texas that are about 2.5 km apart. These two lineaments appear to have created an almost perpendicular bend in a small ephemeral stream. A gravity profile shows approximately a half a mGal gravity anomaly across each of these lineaments. The short wavelength of these anomalies indicates a gravity contribution from a shallow source; however, the small density contrasts common for the shallow sediments in the area cannot account for the entire 0.5 mGal difference in gravity. The linearity to the features, extending for tens to over a hundred kilometers, suggests regional faulting in the subsurface to a significant depth. The best fit gravity model indicates the possibility of listric growth faulting. An electromagnetic survey found shallow, high conductivity anomalies associated with the lineaments. We believe this indicates that these lineaments may result in the erosion of the caliche layer which could become a conduit for infiltration. Continuing work in this area will include mapping in the small canyon caused by the intersection of these lineaments with the small creek intersecting the Yellow House Playa drainage.