title: Salt Dissolution: Examples from Beneath the Southern High Plains
Creators: name: Gustavson, Thomas C.
name: Budnik, Roy T.
Publisher: name: The University of Texas at Austin
Year: 1984
Subjects: subject: geology
subject: salt dissolution
subject: karst
subject: Texas
subject: High Plains

description: Regional salt dissolution and the subsequent collapse of overlying strata have affected substantial parts of the Texas and Oklahoma Panhandles (Gustavson and others, 1980; Johnson, 1981). There are seven salt-bearing units within the Permian System of the Texas Panhandle and eastern New Mexico. With the probable exception of the lower Clear Fork Formation, all the younger salt-bearing units are locally undergoing dissolution. Several lines of evidence support the conclusion that zones of salt dissolution underlie parts of the Southern High Plains, the Rolling Plains, and the Canadian River Breaks (Gustavson and others, 1980, 1982): (1) The major streams draining the region surrounding the Southern High Plains carry high-solute loads, indicating that dissolution is active. For example, the Prairie Dog Town Fork of the Red River carries a mean annual solute load of 1,003.4 x 103 tons of dissolved solids per year, including 425.3 x 103 tons of chloride per year (U.S. Geological Survey, 1969-1977). Brine springs, salt springs, and salt pans appear along this and other stream valleys. (2) The abrupt loss of salt sequences between relatively closely spaced oil and gas exploration wells indicates salt dissolution and not facies change. Structural collapse of overlying strata is evident in the wells where salt is missing (fig. 1). (3) Brecciated zones, fractures with slickensides, extension fractures filled with gypsum, and insoluble residues composed of mud, anhydrite, or dolomite overlie the uppermost salts in cores from the DOE-Gruy Federal No. 1 Rex H. White well in Randall County, the DOE-Gruy Federal No. 1 D. N. Grabbe well and the Stone and Webster Engineering Corp. No. 1 Zeeck and No. 1 Harmon wells in Swisher County, the Stone and Webster Engineering Corp. No. 1 Sawyer well in Donley County, the Stone and Webster Engineering Corp. No. 1 G. Friemel, No. 1 J. Friemel and No. 1 Deten wells in Deaf Smith County, and the Stone and Webster Engineering Corp. No. Mansfield well in Oldham County. (4) Numerous sinkholes and closed depressions (dolines) have formed recently in the Rolling Plains and are interpreted to be the result of dissolution and subsidence (Gustavson and others, 1982). (5) Permian outcrops both east of the Caprock Escarpment and in the Canadian River valley display folds, systems of extension fractures, breccia beds, and remnants of caverns. Structural, stratigraphic, core, and geomorphic evidence suggest that salt dissolution was active beneath the Southern High Plains during the Pliocene and probably the Pleistocene. Two case studies are presented, one describing evidence for dissolution in eastern Deaf Smith County and one describing evidence for dissolution in eastern Swisher County. Using core and stratigraphic data interpretations of the geology in the two case study areas can be extrapolated to the preferred sites in Deaf Smith and Swisher Counties. In each case, it is both reasonable and conservative to infer that dissolution and subsidence of overlying strata occurred during the Pliocene and probably during the Pleistocene.