Analysis of Lineations in the Eagle Flat Study Area, Hudspeth County, Texas

The purpose of this study of the Eagle Flat study area, Hudspeth County, Texas, is to determine the density and orientation of lineaments as part of a characterization study of a proposed site for the Texas low-level radioactive waste repository. Because both the number and total length of lineations per unit area are low at the proposed site (north Paskin Ranch), the results of lineation analyses do not impact repository siting. The lineation study may, however, be a useful adjunct to other ongoing investigations of recharge, Quaternary faulting, geomorphology, and fissures. The scope of this study is to examine the occurrence of lineations on aerial photographs and lineaments on Landsat imagery as they reflect topography and slopes, drainage, bedrock, soils, and geologic structure, as well as the degree to which analysis of linear elements contributes to understanding of both the geologic history of an arid area and the active geologic processes altering the ground surface. Lineations were identified on black-and-white, 1:22,000-scale, stereographic pairs of aerial photographs and transferred to 7.5-minute quadrangles, digitized, statistically analyzed (number, length, and azimuth) per unit area, and printed on maps that were hand-contoured. The study area was divided into 96 unit areas (4 mi2) for analysis. Thirty rectangular areas were selected to characterize the lineations associated with particular stratigraphic, structural, or geomorphic properties. Histograms and scattergrams with straight-line curve-fitting of linear and geologic properties were computed to evaluate the characteristics of the lineations in the 30 selected areas. Five separate areas of Cretaceous outcrop have 26, 27, 28, 29, and 32 lineations per square mile; two Precambrian hills have 59 and 58/mi2. For straight-line curve-fitting of lineation lengths to age and type of bedrock, the R values display correlations of 0.918 to 0.982 for three Precambrian outcrop areas, 0.969 for Permian Hueco Limestone outcrop areas, and 0.886 and 0.873 in two Cretaceous outcrop areas. Azimuth R values are: 0.918, 0.950, and 0.988 (Precambrian), 0.823 (Permian), and 0.919 and 0.983 (Cretaceous). The best correlation of the number of lineations per grid and relief is 0.473, but 0.657 is the R factor of all selected slopes. Lineations were interpreted on seven scenes of Landsat imagery containing the Eagle Flat study area. No lineations pass through or near the proposed site on Paskin Ranch; most lineations parallel structure and drainage.Bureau of Economic Geolog

Physical Envoirnment of Camp Mabry, Austin, Texas

This report describes the physical attributes of Camp Mabry, in Austin, Texas, headquarters of Texas Army National Guard training. This is one of five reports completed on training sites; complementary reports describe training sites at Camp Bowie, Camp Swift, Fort Wolters, and King Ranch. The purpose of these five reports is to provide the natural physical data generally reported in an Environmental Assessment (EA) in conformity with the Environmental Protection Act and to present data applicable to an environmental training manual. The data are presented in text and maps; the maps show spatial layers that can be useful when a Geographic Information System (GIS) is later developed for training site management. Most of the data are collected from available sources in state and federal government reports and files.Bureau of Economic Geolog

Physical Environment of Fort Wolters Military Reservation, Parker and Palo Pinto Counties, Texas

The purpose of this report is to describe the physical environment of Fort Wolters Military Reservation and to call attention to physical processes occurring on the base, to note availability of data, and to comment on potential limitations to land use. Fort Wolters (3,985 ac) is one of the training areas administered by the Texas Adjutant General for activities of the Texas Army National Guard. The Bureau of Economic Geology reviewed existing publications to identify essential baseline data (climate; geology, soil properties, hydrology, and present land condition) and made additional observations that will assist the Texas Adjutant General in preparing long-term environmental assessments mandated by the National Environmental Policy Act and U.S. Environmental Protection Agency regulations and environmental land management and land-condition monitoring plans required by the U.S. Army. This report also includes basic digital line graph (DLG) data sets for cultural features, hydrology, topography, and soils. Fort Wolters is located in North-Central Texas in western Parker County and easternmost Palo Pinto County, about 3 mi northeast of the City of Mineral Wells. The area is within the subtropical subhumid climatic region of Texas, with an average annual precipitation of about 29 inches. Intense thunderstorms result in flashy surface runoff, causing erosion of unprotected soils, and flooding and siltation in area creeks. The principal bedrock geologic unit is the Pennsylvanian Mineral Wells Formation, which consists of shale with interbedded sandstone and limestone. Soils are mostly sandy loam and clayey loam. Because of the shaley nature of the Pennsylvanian strata, there are no major freshwater aquifers beneath the base. Limited amounts of fresh water are present in fractures in limestone and sandstone interbeds.Bureau of Economic Geolog

Development and Application of Operational Techniques for the Inventory and Monitoring of Resources and Uses for the Texas Coastal Zone

There are no author-identified significant results in this report

The Feasibility of Locating a Texas Salt Test Facility

Differences in the geology of dome salt and bedded salt dictate that data and mining experience gained in one environment will not be fully applicable to the other. A test facility in a salt dome could be mined through a relatively thin section of elastic, a cap rock of evaporite minerals that may contain highly porous zones, and possibly 300 m (1,000 ft) of salt. The salt will probably be quite pure except for a few percent anhydrite, increasing in concentration toward the top of the salt stock (Balk, 1949; Muehlberger, 1959; and Dutton and Kreitler, 1980). Infrequent inclusions of the surrounding sediments may be found in dome salt that has been highly contorted and whose crystals show translational gliding as a result of salt dome emplacement (Muehlberger, 1959; Clabaugh, 1962; and Hofrichter, 1968). Access to bedded salt will require mining through a sequence of predominantly terrigenous elastics and evaporites. The degree of consolidation, porosity, and permeability of these sediments will vary between horizons. The objective interval will be a required thickness of relatively pure salt. Crystallographic properties, water content, and elastic inclusions will be results of the original depositional environment rather than emplacement of a salt stock. The feasibility of locating a Salt Test Facility in Texas has been studied and evaluated. Measured parameters are summarized in table 1. For primarily technical reasons, the most feasible Texas sites are the Gyp Hill salt dome in Brooks County or bedded salt in Loving County.Bureau of Economic Geolog

Initial Report on the Geology of the Northeastern Part of the New Braunfels, Texas

This brief report describes initial progress on geologic mapping and paleontologic studies that are being conducted in the vicinity of New Braunfels, Texas. The primary objective of this work is to produce an accurate geologic map that will be printed on the new 1:100,000-scale map of the New Braunfels, Texas, 30 X 60 minute quadrangle, which is in preparation by the U.S. Geological Survey. A planimetric version has been printed, but the final topographic map is not yet available. Our initial mapping has been completed on 1:24,000-scale topographic maps and is intended for compilation at 1:100,000-scale. Partial funding for the second year of the study has been approved. Work during year two will continue the mapping into quadrangles adjacent to those mapped in year one. Paleontologic work by Dr. Will Elder will continue as part of the in-kind contribution by the U.S. Geological Survey to this effort. Dr. E. G. Wermund has described this project to several groups for whom the geology of this area is of interest. Draft copies of the mapping accomplished to date have been given to the Edwards Underground Water District, potentially for entry by them into a GIS, and copies will be made available to other interested parties as requested. In addition, the South Texas Geological Society has passed a resolution commending this initiative, supporting this new mapping effort, and offering the help of their membership.Bureau of Economic Geolog

Preliminary Evaluation of the Eagle Flat Region Hudspeth County, Texas

Preliminary evaluation of the Eagle Flat region, as designated by the Texas Legislature, indicates several areas that may have geologic and hydrologic conditions favorable for further evaluation as potential siting areas for the Texas low-level radioactive waste repository. This determination is based on a review of available data regarding surface drainage, thickness and character of alluvial fill, depth to groundwater, and apparent presence or absence of such features as late Cenozoic faults, fissures, known natural resources, and evidence of erosion. Some general siting areas have been identified that contain several sections that appear to have favorable characteristics. Examples of apparently favorable general siting areas are east of Yucca Mesa, south of Eagle Flat Mountain, and north of Little Hills. Our preliminary assessment is that, of the three areas cited above, the Yucca Mesa location should be given priority consideration. Initial flooding and drainage analysis indicates that the Yucca Mesa site includes sufficient surface areas unaffected by flooding. There are no known fissures or late Cenozoic faults. Depth to groundwater may be in excess of 500 ft, and the water quality may be poor. Shallow alluvium may be somewhat finer grained than at other settings, and the surface appears to be relatively stable and devoid of major incision by existing drainages. Although each of these characteristics needs to be investigated by further work, the most critical unanswered question is the thickness of alluvial fill. Available gravity data, including recent work by The University of Texas at El Paso, indicates that 100 ft or more of alluvial fill may be present in the area. Other areas may be present that are of equal or similar merit, but the preliminary analysis and available information suggest that the Yucca Mesa location apparently has the most favorable characteristics of those general siting areas identified currently. Smaller potential siting areas, generally about 400 to 800 acres in size, also may exist locally throughout the region where alluvial fill may be of sufficient thickness and drainage characteristics may be appropriate. These smaller potential siting areas would require additional site-specific evaluation of surface drainage characteristics before drill testing could be recommended. Any potential siting area is unique and would require site-specific evaluation activities to assess its suitability for characterization.Bureau of Economic Geolog

Secondary Natural Gas Recovery: Targeted Technology Applications for Infield Reserve Growth

Activities during the year comprised screening and selection of gas fields for detailed studies; integrated geological, petrophysical, geophysical, and engineering analyses of the fields selected; and data acquisition in cooperative wells. A comprehensive workplan was prepared, and a methodology for geological and engineering screening of sandstone reservoirs was developed and applied to leading candidate fields. Contacts made with field operators resulted in active participation of Mobil Exploration and Producing U.S., Inc., and Shell Western Exploration and Production Inc. Lake Creek, Seeligson, McAllen Ranch, and Stratton-Agua Dulce fields were selected for study. These fields are representative of a spectrum of depositional systems and reservoir heterogeneities in highly productive gas reservoirs in the Texas coastal plain. Producing intervals are fluvial Frio reservoirs in Seeligson and Stratton-Agua Dulce fields, deltaic Vicksburg reservoirs in McAllen Ranch field, and deltaic Wilcox reservoirs in Lake Creek field. New data, comprising cores, open- and cased-hole logs, vertical seismic profiles, and sequential formation-pressure tests, were acquired in two wells in Seeligson field and in one well in McAllen Ranch field. Results to date suggest that reservoir heterogeneity can be defined using integrated geologic, geophysical, and engineering data.Bureau of Economic Geolog

Coplanar microwave filters with YBa2Cu3O7-delta thin films on sapphire substrates

A bandpass filter for a I dB relative bandwidth of 2.5% at 1.417 GHz is implemented with five end coupled resonators of meander coplanar fines with air bridges for ground connections on a 4.0 x 2.6 CM2 substrate. A single sided sputtered YBa2Cu3O7-delta film with a CeO2 buffer layer on a sapphire substrate is patterned with an Ar ion beam. The wanted bandwidth of 35 MHz near 1.4 GHz is measured with a minimum insertion loss smaller than 0.1 dB at 15 K. Filters for a two channel receiver with almost identical characteristics have been fabricated without manual tuning screws. In the passband an insertion loss difference of less than 0.2 dB has been achieved. Their characteristics are not affected by mechanical vibrations on a cold finger. To attenuate higher order pass bands the design of a superconducting low pass filter is discussed. (C) 2002 Elsevier Science B.V. All rights reserved