Characterization and Delineation of Gypsum Karst Geohazards Using 2D Electrical Resistivity Tomography in Culberson County, Texas, USA

Abstract

The Delaware Basin of W Texas and SE New Mexico is the western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karstification. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin. Land reconnaissance surveys conducted during 2015 and 2016 documented abundant karst landforms near major thoroughfares in Culberson County, Texas. Two dimensional (2D) electrical resistivity surveys were conducted at four sites to characterize and delineate karst related hazards, both laterally and vertically, associated with the road. The electrical resistivity data were collected with a multi-electrode earth resistivity meter using a dipole-dipole array configuration. The resistivity data were then processed using EarthImager2D to produce inverted profile sections of each site. Two-dimensional electrical resistivity tomography was shown to be an effective non-invasive method in detecting solution conduits, soil filled voids, and fractured bedrock in the shallow subsurface in addition to those directly observed on the surface.