Fissurelike features in ephemeral channels, Trans-Pecos Texas
- Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology
Active and relict ephemeral channels in the Eagle Flat basin west of Van Horn contain abundant fissurelike features, which are being studied as part of the geologic characterization of a proposed site for the Texas low-level radioactive waste repository. Tensional cracks are absent in excavations of fissurelike features in Eagle Flat, so the term fissurelike' is used instead of fissure'. Fissurelike features in active channels are characterized by curvilinear patterns of holes, pipes, and collapse structures developed at the surface within silt and fine sand basin-fill sediments. Typical single depressions range from 20 to 40 cm in depth and 0.4 to 2 m in length and form clusters as much as 2,000 m in length. Relict channel deposits exhibit filled burrows and sandy crossbedded deposits. Linear fissurelike features, located in silts and clays at the surface, may have been the loci for shallow infiltration of surface waters, which caused dissolution and reprecipitation of calcic soils. Ground-water withdrawal, a cause of fissure development elsewhere in the southwest, is an unlikely origin for fissures at this location because pumpage from nearby wells is minimal. Fissurelike features, where excavated, are not underlain by tensional cracks. In addition, the features are located in low-gradient ephemeral channel areas, and are most abundant gown gradient from a railroad embankment where water ponds relatively frequently. Localized wetting and soil-collapse processes, rather than basinal-scale tensional stresses produced by ground-water withdrawal, may have caused most of the fissurelike features in northern Eagle Flat basin.
- OSTI ID:
- 6057734
- Report Number(s):
- CONF-9303212-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:1; Conference: 27. annual Geological Society of America (GSA) South-Central Section meeting, Fort Worth, TX (United States), 15-16 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Impact of late Cenozoic extension on Laramide overthrust belt and Diablo Platform margins, northwestern Trans-Pecos Texas
Re-Introduction of Lower Columbia River Chum Salmon into Duncan Creek, 2002-2003 Annual Report.
Related Subjects
58 GEOSCIENCES
RADIOACTIVE WASTE FACILITIES
GEOLOGY
SITE CHARACTERIZATION
TEXAS
GEOLOGIC FISSURES
GEOLOGIC FRACTURES
LOW-LEVEL RADIOACTIVE WASTES
RADIOACTIVE WASTE DISPOSAL
SEDIMENTARY BASINS
DEVELOPED COUNTRIES
GEOLOGIC STRUCTURES
MANAGEMENT
MATERIALS
NORTH AMERICA
NUCLEAR FACILITIES
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE MANAGEMENT
RADIOACTIVE WASTES
USA
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage
580000 - Geosciences