Areal geology of Painthorse quadrangle Culberson County, Texas




Blankenship, Asa Lee, 1926-

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Painthorse quadrangle is structurally high on an eastward-sloping homoclinal flexure of the Delaware Mountains. This quadrangle is divided into two major lithic units; the gypseous Castile is the bedrock formation of the eastern half of the quadrangle, the limestones and sandstones of the Delaware Mountain group comprising the western half. The western half of the quadrangle is an area of low, rolling hills and flat, broad valleys. The soil is extremely fertile. Paleontological evidence supports the presence of the Manzanita limestone member of the Cherry Canyon. The South Wells member could be present. The Lamar member of the Bell Canyon formation is exposed as a westward-facing cuesta. The weathering characteristics of the Castile gypsum directly control the topography of the eastern half of the quadrangle; the result is a karst topography. The soil derived from the Castile is almost sterile and the plants growing in it are especially adapted to its chemical make-up. The Rustler formation is found only as caps on the highest hills. The Cretaceous Cox sandstone unconformably overlies the Permian Pierce Canyon redbeds. Conglomerates composed of various ratios of Cox, Pierce Canyon and Rustler pebbles occur as sinkhole deposits throughout the area