Geology topics

Research about Texas

Source-linked reports with geographic coverage including Texas.

At least 271 records · Page 15Linked to original sources

USGS2014

The use of resistivity‐methods in the location of salt‐water bodies in the El Paso, Texas, Area

During 1935 and 1936 the Ground‐Water Division of the United States Geological Survey made an investigation of the ground‐water resources of the El Paso, Texas, Area. Geological and hydrological studies comprised the principal part of the investigation, and these studies were supplemented by measurements of earth‐resistivity made largely by the Geophysical Section of the Geological Survey along traverses aggregating 51 miles. The extent to which resistivity‐methods may be useful in ground‐water work has been the subject of much discussion. A full evaluation of the method can not be made at this time. However, the work in the El Paso Area indicates that the presence of faults and of underground bodies of salt water may be definitely determined by resistivity‐measurements.

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USGS2014

Coefficients of storage and transmissibility obtained from pumping tests in the Houston District, Texas

An investigation of the ground‐water supply of the Houston District, in Texas, has been in progress since December, 1930, under the general direction of O. E. Meinzer, Geologist‐in‐Charge of the Division of Ground Water of the Geological Survey. The Houston District, as the term is used here, comprises all of Harris County and parts of Montgomery, Waller, and Fort Bend counties, lying between the Trinity and Brazos rivers. The investigation in this area has consisted primarily of inventorying well‐logs and pumpage‐records, of obtaining water‐level data and information regarding the chemical character of the ground‐water, and wherever possible of correlating these data.

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USGS2014

Application of coefficients of transmissibility and storage to regional problems in the Houston District, Texas

The Houston District, as the term is used in this paper, comprises an area between the Trinity and Brazos rivers in Harris County and parts of Montgomery, Waller, and Fort Bend counties, Texas. It consists of a plain of low relief that lies not far above sea‐level, and is a part of the West Gulf Coastal Plain. A part of the District is shown in Figure 1. Large quantities of ground‐water are pumped in the Houston District from a succession of beds of sand that occur between 300 and 1,900 feet below the surface. These sands are interbedded with relatively impermeable clays. The formations range in age from Miocene to Recent and were deposited during several cycles of marine and continental deposition. They may be classified into several zones which are predominantly clay or predominantly sand, but in which the individual beds at most horizons can not be traced very far. Most of the beds interfinger and grade into one another laterally and vertically in short distances, the thinner beds in many places changing character or pinching out within a few hundred feet. The formations dip to the southeastward, the dip ranging from about 35 feet to the mile in the older formations to about 20 feet to the mile in the younger. In the outcrop‐areas of the formations, and for considerable distances down the dip, the sediments are in general dominantly sandy. Far to the southeastward, in the direction of the Gulf, clay predominates.

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USGS2014

Recharge, movement, and discharge in the Edwards Limestone Reservoir, Texas

The Edwards limestone of Lower Cretaceous age is the principal water‐bearing formation in a belt 5 to 25 miles wide that extends from Austin southwest to San Antonio and thence west through Uvalde and Del Rio to Comstock, a distance of about 250 miles (see Fig. 1). Throughout this belt it supplies water to wells for stock, industrial, irrigation, and municipal use and to a series of fault‐springs, some of which are among the largest in the United States. These springs have played an important part in the economic and cultural development of Texas. In 1718 the Spaniards stationed a department of light infantry near the springs at San Antonio and soon after established missions and constructed elaborate systems of canals for irrigating considerable areas. After the winning of Texas' independence large numbers of settlers moved into the area. This influx was greatly accelerated following the admission of Texas to the Federal Union and towns were soon established near all of the major springs. However, it was not until about 1880 that the rapid development of the Edwards limestone aquifer by wells was begun.

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USGS2014

Results of pumping tests of the Carrizo sand in the Lufkin area, Texas

The Lufkin Area, as the term is used in this paper, is comprised of Angelina and Nacogdoches counties, Texas, and parts of adjoining counties. Its surface is gently rolling, with a maximum relief of about 150 feet and a maximum altitude of less than 400 feet. The average annual rainfall is about 45 inches. Practically all of the water‐supplies in the area come from ground‐water and it has been found that the Carrizo sand contains water of better quality and is more productive than any other water‐bearing formation in the area [see 1 of “References” at end of paper]. Figure 1 is a map of the area, showing the positions of the cities of Lufkin and Nacogdoches, the wells of the Southland Paper Mill, and other wells mentioned in this paper.

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USGS2014

Value of the electrical log for estimating ground‐water supplies and the quality of the ground water

This paper gives a brief summary of studies of the value of the electrical log for estimating ground‐water supplies and the quality of the water in them made in Texas by the United States Geological Survey and cooperating parties. The electrical log has been found to be especially valuable in the Coastal Plain Region of Texas where the rocks consist mostly of a succession of clays or shales or sandy clays or shales lnterbedded with sands or sandstones. In that region the electrical log has been found to be more useful than the driller's log for correlating the principal water‐bearing horizons over wide areas. The log by itself is not an indicator of the permeability of the water‐bearing beds, nor a safe guide as to the quality of the water in them, but if it is studied in connection with other data, it is sure to tell an interesting and instructive story. Thus far in Texas no extensive studies have been made of the value of the electrical log in limestone aquifers or in sand or sandstone aquifers associated with limestone.

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USGS2014

Development of limestone reservoirs in Comal County, Texas

The Edwards limestone, and to a lesser extent the Comanche Peak limestone and the lower part of the Glen Rose limestone below, all of Lower Cretaceous age, form one of the most extensive ground‐water reservoirs in Texas. As a result of normal faulting, these formations are connected by underground channels to form a hydrologic unit which is partly artesian and partly unconfined. Observations in Comal County show that the development of the reservoir by solution is closely related to the geologic history, in which complex faulting and the disconformity between the Edwards and Georgetown limestones are important factors. Various phases of development are shown in different fault blocks, depending upon length of exposure at the surface. The Edwards limestone, which contains the main channels of underground drainage, is almost uniformly permeable from top to bottom, whereas the older, but more recently exposed lower part of the Glen Rose limestone is generally relatively impermeable except where exposed by mature streams.

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USGS2014

Nitrate in the ground water of Texas

Ground water in many parts of Texas contains nitrate in excess of 20 ppm (parts per million) as NO 3 . About 3,000 of the 20,000 nitrate determinations made of water from wells in Texas showed more than 20 ppm of nitrate . The public water supplies of 27 Texas towns and cities contained more than 50 ppm of nitrate . Recent medical research indicates that methemoglobinemia or infant cyanosis (“blue babies”) may be caused by nitrate in water used in formula mixtures. Most of the high nitrate in ground water is found in wells less than 200 ft deep and mainly in water from late Tertiary and Quaternary formations; however, high nitrate was found in water from all kinds of rocks of all ages. The presence of high nitrate in ground water appears to be unrelated to rainfall, geography, or cultivation. A hypothesis of bacterial origin of the high nitrate is supported by strong evidence but is weakened by the presence of the correspondingly high content of associated salts. The disappearance of nitrate at depth presents additional problems.

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USGS2014

Distribution and habitat associations of juvenile Common Snook in the lower Rio Grande, Texas

Common Snook Centropomus undecimalis were once abundant off the Texas coast, but these populations are now characterized by low abundance and erratic recruitment. Most research concerning Common Snook in North America has been conducted in Florida and very little is known about the specific biology and habitat needs of Common Snook in Texas. The primary objective of this study was to describe the habitat use patterns of juvenile Common Snook and their role in the fish assemblage in the lower portion of the Rio Grande, Texas. Secondarily, we documented the relationship between age and juvenile reproductive development. Fish were collected during January–March 2006 from the lower 51.5 km of the Rio Grande using a bottom trawl and boat-mounted electrofisher. Measurements of water quality and other habitat traits were recorded at each sampling site. We captured 225 Common Snook exclusively in freshwater habitats above river kilometer 12.9. The distribution of juvenile Common Snook was not random, but influenced primarily by turbidity and dissolved oxygen. Sex differentiation and gonadal development based on histological examination of gonads established that age-1 and age-2 Common Snook were juvenile, prepubertal males. There was no difference between the age groups in their overall distribution in the river. However, age-2 Common Snook were associated with deeper areas with faster currents, higher conductivity, and steeper banks. Overall, Common Snook in the lower Rio Grande show substantial differences in habitat use than their counterparts in other parts of the range of the species, but it is unclear whether this is due to differences in habitat availability, behavioral plasticity, or some combination thereof.

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USGS2014

Mercury concentrations and distribution in soil, water, mine waste leachates, and air in and around mercury mines in the Big Bend region, Texas, USA

Samples of soil, water, mine waste leachates, soil gas, and air were collected from areas mined for mercury (Hg) and baseline sites in the Big Bend area, Texas, to evaluate potential Hg contamination in the region. Soil samples collected within 300 m of an inactive Hg mine contained elevated Hg concentrations (3.8–11 µg/g), which were considerably higher than Hg in soil collected from baseline sites (0.03–0.05 µg/g) distal (as much as 24 km) from mines. Only three soil samples collected within 300 m of the mine exceeded the probable effect concentration for Hg of 1.06 µg/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of Hg in mine water runoff (7.9–14 ng/L) were generally higher than those found in springs and wells (0.05–3.1 ng/L), baseline streams (1.1–9.7 ng/L), and sources of drinking water (0.63–9.1 ng/L) collected in the Big Bend region. Concentrations of Hg in all water samples collected in this study were considerably below the 2,000 ng/L drinking water Hg guideline and the 770 ng/L guideline recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic wildlife from chronic effects of Hg. Concentrations of Hg in water leachates obtained from leaching of mine wastes varied widely from <0.001 to 760 µg of Hg in leachate/g of sample leached, but only one leachate exceeded the USEPA Hg industrial soil screening level of 31 µg/g. Concentrations of Hg in soil gas collected at mined sites (690–82,000 ng/m 3 ) were highly elevated compared to soil gas collected from baseline sites (1.2–77 ng/m 3 ). However, air collected from mined areas at a height of 2 m above the ground surface contained concentrations of Hg (4.9–64 ng/m 3 ) that were considerably lower than Hg in soil gas from the mined areas. Although concentrations of Hg emitted from mine-contaminated soils and mine wastes were elevated, persistent wind in southwest Texas disperses Hg in the air within a few meters of the ground surface.

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USGS2014

PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas

Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin’s ban by analyzing PAHs in sediment cores and bottom-sediment samples collected in 1998, 2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving water body for Austin urban runoff. The sum concentration of the 16 EPA Priority Pollutant PAHs (∑PAH 16 ) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998–2005 to 2006–2014 (means of 7980 and 4500 μg kg –1 , respectively), and by 2012–2014, the decline was about 58% (mean of 3320 μg kg –1 ). Concentrations of ∑PAH 16 in bottom sediment from two of three mid-lake sites decreased by about 71 and 35% from 2001 to 2014. Concentrations at a third site increased by about 14% from 2001 to 2014. The decreases since 2006 reverse a 40-year (1959–1998) upward trend. Despite declines in PAH concentrations, PAH profiles and source-receptor modeling results indicate that coal-tar sealants remain the largest PAH source to the lake, implying that PAH concentrations likely will continue to decline as stocks of previously applied sealant gradually become depleted.

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USGS2014

Nesting ecology and nest survival of lesser prairie-chickens on the Southern High Plains of Texas

The decline in population and range of lesser prairie-chickens ( Tympanuchus pallidicinctus ) throughout the central and southern Great Plains has raised concerns considering their candidate status under the United States Endangered Species Act. Baseline ecological data for lesser prairie-chickens are limited, especially for the shinnery oak-grassland communities of Texas. This information is imperative because lesser prairie-chickens in shinnery oak grasslands occur at the extreme southwestern edge of their distribution. This geographic region is characterized by hot, arid climates, less fragmentation, and less anthropogenic development than within the remaining core distribution of the species. Thus, large expanses of open rangeland with less anthropogenic development and a climate that is classified as extreme for ground nesting birds may subsequently influence nest ecology, nest survival, and nest site selection differently compared to the rest of the distribution of the species. We investigated the nesting ecology of 50 radio-tagged lesser prairie-chicken hens from 2008 to 2011 in the shinnery oak-grassland communities in west Texas and found a substantial amount of inter-annual variation in incubation start date and percent of females incubating nests. Prairie-chickens were less likely to nest near unimproved roads and utility poles and in areas with more bare ground and litter. In contrast, hens selected areas dominated by grasses and shrubs and close to stock tanks to nest. Candidate models including visual obstruction best explained daily nest survival; a 5% increase in visual obstruction improved nest survival probability by 10%. The model-averaged probability of a nest surviving the incubation period was 0.43 (SE = 0.006; 95% CI: 0.23, 0.56). Our findings indicate that lesser prairie-chicken reproduction during our study period was dynamic and was correlated with seasonal weather patterns that ultimately promoted greater grass growth earlier in the nesting season that provided visual obstruction from predators.

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USGS2014

The 17 May 2012 M4.8 earthquake near Timpson, East Texas: An event possibly triggered by fluid injection

This study summarizes our investigation of the 17 May 2012 MW-RMT4.8 earthquake near Timpson, Texas, the largest earthquake recorded historically in eastern Texas. To identify preshocks and aftershocks of the 17 May event we examined the arrivals recorded at Nacogdoches (NATX) 30 km from the 17 May epicenter, at nearby USArray Transportable Array stations, and at eight temporary stations deployed between 26 May 2012 and mid-2013. At NATX we identified seven preshocks, the earliest occurring in April 2008. Reliably located aftershocks recorded by the temporary stations lie along a 6 km long NW-SE linear trend corresponding to a previously mapped basement fault that extends across the highest-intensity (MMI VII) region of the 17 May main shock. Earthquakes in this sequence are relatively shallow—with focal depths ranging from 1.6 to 4.6 km. Evidence supporting these depths include: hypocentral locations of exceptionally well-recorded aftershocks, S-P intervals at the nearest stations, and comparisons of synthetics and observed seismograms. Within 3 km of the linear trend of aftershock activity there are two Class II injection disposal wells injecting at 1.9 km depth beginning in August 2006 and February 2007, with injection rates averaging 42,750 m3/mo and 15,600 m3/mo, respectively. Several observations support the hypothesis that fluid injection triggered the Timpson sequence: well-located epicenters are situated near a mapped basement fault and near high-volume injection wells, focal depths are at or below the depths of injection, and the earliest preshock (April 2008) occurred after the onset of injection in 2006.

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USGS2014

Raptor abundance and northern bobwhite survival and habitat use

Predation risk has a profound influence on prey behavior and habitat use. The Rio Grande Plains ecoregion of Texas, USA, provides a unique opportunity to investigate changes in prey behavior because the ecoregion experiences a high influx of raptors every year during autumn migration. We used an 8-year data set (2000–2008) of radiocollared northern bobwhites ( Colinus virginianus ) and raptor abundance to test the hypothesis that bobwhites responded to increased raptor abundance via changes in woody-cover use at the home-range scale. Bobwhite survival was negatively correlated with raptor abundance, with red-tailed hawks ( Buteo jamaicensis ), and northern harriers ( Circus cyaneus ) accounting for 51% of the variability in bobwhite survival ( P  < 0.010). However, we documented no change in the amount of woody cover used by bobwhites in their home range between the raptor migration (6.6% ± 0.5%; n  = 73 bobwhites) and non-migration periods (7.1% ± 0.4%; n  = 105 bobwhites; P  = 0.490). In addition, bobwhites that survived the raptor migration period used similar amounts of woody cover within their home range (6.3% ± 0.6%, n  = 58 bobwhites) compared with those dying during the migration period (6.8% ± 0.4%, n  = 100 bobwhites; P  = 0.530). Our data suggest that bobwhites do not alter their use of woody cover at the home-range scale in response to increasing raptor abundance, but this does not preclude increased use of woody cover at the point-of-use scale.

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USGS2014

Changing amounts and sources of moisture in the U.S. southwest since the Last Glacial Maximum in response to global climate change

The U.S. southwest has a limited water supply and is predicted to become drier in the 21st century. An improved understanding of factors controlling moisture sources and availability is aided by reconstruction of past responses to global climate change. New stable isotope and growth-rate records for a central Texas speleothem indicate a strong influence of Gulf of Mexico (GoM) moisture and increased precipitation from 15.5 to 13.5 ka, which includes the majority of the Bølling–Allerød warming (BA: 14.7–12.9 ka). Coeval speleothem records from 900 and 1200 km to the west allow reconstruction of regional moisture sources and atmospheric circulation. The combined isotope and growth-rate time series indicates 1) increased GoM moisture input during the majority of the BA, producing greater precipitation in Texas and New Mexico; and 2) a retreat of GoM moisture during Younger Dryas cooling (12.9–11.5 ka), reducing precipitation. These results portray how late-Pleistocene atmospheric circulation and moisture distribution in this region responded to global changes, providing information to improve models of future climate.

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USGS2014

Application of spatially gridded temperature and land cover data sets for urban heat island analysis

Two gridded data sets that included (1) daily mean temperatures from 2006 through 2011 and (2) satellite-derived impervious surface area, were combined for a spatial analysis of the urban heat-island effect within the Dallas-Ft. Worth Texas region. The primary advantage of using these combined datasets included the capability to designate each 1 × 1 km grid cell of available temperature data as urban or rural based on the level of impervious surface area within the grid cell. Generally, the observed differences in urban and rural temperature increased as the impervious surface area thresholds used to define an urban grid cell were increased. This result, however, was also dependent on the size of the sample area included in the analysis. As the spatial extent of the sample area increased and included a greater number of rural defined grid cells, the observed urban and rural differences in temperature also increased. A cursory comparison of the spatially gridded temperature observations with observations from climate stations suggest that the number and location of stations included in an urban heat island analysis requires consideration to assure representative samples of each (urban and rural) environment are included in the analysis.

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USGS2014

Regression models of discharge and mean velocity associated with near-median streamflow conditions in Texas: utility of the U.S. Geological Survey discharge measurement database

A database containing more than 16,300 discharge values and ancillary hydraulic attributes was assembled from summaries of discharge measurement records for 391 USGS streamflow-gauging stations (streamgauges) in Texas. Each discharge is between the 40th- and 60th-percentile daily mean streamflow as determined by period-of-record, streamgauge-specific, flow-duration curves. Each discharge therefore is assumed to represent a discharge measurement made for near-median streamflow conditions, and such conditions are conceptualized as representative of midrange to baseflow conditions in much of the state. The hydraulic attributes of each discharge measurement included concomitant cross-section flow area, water-surface top width, and reported mean velocity. Two regression equations are presented: (1) an expression for discharge and (2) an expression for mean velocity, both as functions of selected hydraulic attributes and watershed characteristics. Specifically, the discharge equation uses cross-sectional area, water-surface top width, contributing drainage area of the watershed, and mean annual precipitation of the location; the equation has an adjusted R-squared of approximately 0.95 and residual standard error of approximately 0.23 base-10 logarithm (cubic meters per second). The mean velocity equation uses discharge, water-surface top width, contributing drainage area, and mean annual precipitation; the equation has an adjusted R-squared of approximately 0.50 and residual standard error of approximately 0.087 third root (meters per second). Residual plots from both equations indicate that reliable estimates of discharge and mean velocity at ungauged stream sites are possible. Further, the relation between contributing drainage area and main-channel slope (a measure of whole-watershed slope) is depicted to aid analyst judgment of equation applicability for ungauged sites. Example applications and computations are provided and discussed within a real-world, discharge-measurement scenario, and an illustration of the development of a preliminary stage-discharge relation using the discharge equation is given.

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USGS2014

Key subsurface data help to refine Trinity aquifer hydrostratigraphic units, south-central Texas

The geologic framework and hydrologic characteristics of aquifers are important components for studying the nation’s subsurface heterogeneity and predicting its hydraulic budgets. Detailed study of an aquifer’s subsurface hydrostratigraphy is needed to understand both its geologic and hydrologic frameworks. Surface hydrostratigraphic mapping can also help characterize the spatial distribution and hydraulic connectivity of an aquifer’s permeable zones. Advances in three-dimensional (3-D) mapping and modeling have also enabled geoscientists to visualize the spatial relations between the saturated and unsaturated lithologies. This detailed study of two borehole cores, collected in 2001 on the Camp Stanley Storage Activity (CSSA) area, provided the foundation for revising a number of hydrostratigraphic units representing the middle zone of the Trinity aquifer. The CSSA area is a restricted military facility that encompasses approximately 4,000 acres and is located in Boerne, Texas, northwest of the city of San Antonio. Studying both the surface and subsurface geology of the CSSA area are integral parts of a U.S. Geological Survey project funded through the National Cooperative Geologic Mapping Program. This modification of hydrostratigraphic units is being applied to all subsurface data used to construct a proposed 3-D EarthVision model of the CSSA area and areas to the south and west.

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