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Sample records for grande embayment texas

  1. Stratigraphy and sedimentology of Kincaid Formation, Midway Group (Paleocene), Upper Rio Grande Embayment, Texas

    SciTech Connect

    Roy, E.C. Jr.

    1984-09-01

    Sedimentary rocks of the Kincaid Formation crop out along the northern and western edges of the Rio Grande Embayment. Siltstones are exposed at the type locality of the Kincaid Formation along the Frio River in Uvalde County, Texas. On the east and south, the Kincaid Formation changes facies to richly fossiliferous carbonate rocks; however, basinward, it grades into a shale facies that contains interbedded units of fine-grained sandstone. At the type locality of the Kincaid Formation, approximately 30 ft (9 m) of massive siltstone grades upward into a very silty limestone unit. Bedding is poorly defined throughout the section, largely the result of intensive bioturbation. The grain size of the siltstone increases upward, ranging from medium to coarse. Clay content in the siltstone decreases upward as the amount of calcareous material increases. The upper 4-6 ft (1.2-1.8 m) may actually be considered a silty limestone. A dramatic facies change is present along the outcrop both east and south of the type section. To the east, the Kincaid Formation is composed of glauconitic and highly fossiliferous limestone. The siltstone present at the type locality thins eastward and is absent less than 20 mi (32 km) away. Eighty miles (130 km) to the south, along the Rio Grande River, approximately 45 ft (14 m) of limestone and shale comprise the Kincaid Formation. These early Paleocene sediments are interpreted to be shallow marine in origin. The siltstone represents a shallow sublittoral shoreface environment whereas the limestones on the east and south were deposited in shallow nearshore environments beyond the reach of clastic deposition.

  2. Creationism in the Grand Canyon, Texas Textbooks

    NASA Astrophysics Data System (ADS)

    Folger, Peter

    2004-01-01

    AGU President Bob Dickinson, together with presidents of six other scientific societies, have written to Joseph Alston, Superintendent of Grand Canyon National Park, pointing out that a creationist book, The Grand Canyon: A Different View, is being sold in bookstores within the borders of the park as a scientific explanation about Grand Canyon geologic history. President Dickinson's 16 December letter urges that Alston clearly separate The Grand Canyon: A Different View from books and materials that discuss the legitimate scientific understanding of the origin of the Grand Canyon. The letter warns the Park Service against giving the impression that it approves of the anti-science movement known as young-Earth creationism, or that it endorses the advancement of religious tenets disguised as science. The text of the letter is on AGU's Web site http://www.agu.org/sci_soc/policy/sci_pol.html. Also, this fall, AGU sent an alert to Texas members about efforts by intelligent design creationists aimed at weakening the teaching of biological evolution in textbooks used in Texas schools. The alert pointed scientists to a letter, drafted by AGU, together with the American Institute of Physics, the American Physical Society, the Optical Society of America, and the American Astronomical Society, that urged the Texas State Board of Education to adopt textbooks that presented only accepted, peer-reviewed science and pedagogical expertise. Over 550 scientists in Texas added their names to the letter (http://www.agu.org/sci_soc/policy/texas_textbooks.pdf ), sent to the Board of Education on 1 November prior to their vote to adopt a slate of new science textbooks. The Board voted 11-5 in favor of keeping the textbooks free of changes advocated by groups supporting intelligent design creationism.

  3. Structural evolution of the Abiquiu embayment, Rio Grande Rift: Implications for the development of transfer zones.

    NASA Astrophysics Data System (ADS)

    Hicks, R. T.; Murphy, M. A.

    2006-12-01

    The Abiquiu embayment is located along the boundary between the Colorado Plateau and the Rio Grande rift in north central New Mexico. It is an early rift basin bordered by the Canones fault system on its west side that is oblique to the regional trend of the Rio Grande rift and lies within a region where the polarity of the rift changes. Knowledge of the geometry, kinematics, and slip history of the basin-bounding faults is important in understanding segmentation of the Rio Grande rift and may shed light on the development of transform zones in general. We present geologic mapping, stratigraphic analysis and structural analyses of geologic features in the Abiquiu area to assess the role of Abiquiu embayment in the development of the Rio Grande rift. Our mapping shows that the Canones fault system is an east-dipping, oblique normal fault system that strikes northeast for approximately 20 km. It juxtaposes Permian and Triassic age formations in its footwall against upper Jurassic rocks and 300 m of Tertiary basin fill in its hanging wall. Attitudes of pre-rift strata in the hanging wall define a basin-scale rollover structure, which implies the fault system is listric at depth. Fault slip data collected from the Canones fault system shows the mean slip direction is ENE, which yields nearly equal components of left- slip and normal dip-slip. Mode 1 fractures adjacent to the fault system strike between N20E and N47E, an orientation similar to the strike of basaltic dikes several kilometers east of the surface trace of the Canones fault system. Restoration of the contact between Permian and Triassic-age rocks in a direction parallel to the mean slip direction yields slip estimates that show along strike changes. In the southern part of the study area we estimate 300 m of net slip. In the north, we estimate approximately 425 m. The majority of the total slip occurred before deposition of the 8-10 Ma Lobato basalt. Offset of this basalt unit is less than 50 m, implying

  4. Remote Sensing of Exotic Invasive Weeds in the Rio Grande System of Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic invasive weeds are a serious problem in the Rio Grande system of Texas. This paper presents the results of several aerial remote sensing studies conducted from 2002 to 2006 on the Rio Grande from its mouth near Brownsville in south Texas to El Paso in west Texas. Weed species addressed inc...

  5. Llano Grande Center's Oral History Project Sparks Cultural and Economic Renewal in Texas's Rio Grande Valley. Rural Trust Featured Project.

    ERIC Educational Resources Information Center

    Null, Elizabeth Higgins

    The Llano Grande Center for Research and Development started as an oral history experiment in two of Texas's poorest school districts. Since the 1920s, when this arid region in the southernmost tip of Texas was first transformed into the orchards and farmlands of the "Magic Valley," workers of Mexican descent have worked the land. Over time,…

  6. Short-term community transition and selection in shallow marine embayment fauna from Pennsylvanian of north-central Texas

    SciTech Connect

    Cate, A.S.

    1988-02-01

    Community and size-frequency analyses were obtained for macrofauna from a thin fossiliferous interval within an otherwise barren shallow marine embayment facies in the East Mountain Shale (Strawn Group). Vertically contiguous sampling of this discrete unit allowed reconstruction of short-term community transition and detection of shifts in the population structure of two gastropod species (Glabrocingulum G. grayvillensis, Straparollus A. catilloides). These biological phenomena could be related to environmental shifts brought about by deltaic progradation.

  7. View of northeastern Mexico and the Rio Grande Valley of Texas

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An oblique view of northeastern Mexico and the Rio Grande Valley of Texas (26.0N,100.0W), as photographed from the Skylab space station by one of the Skylab 4 crewmen. Mexico's Sierra Madre Oriental Mountains are in the center of the picture. The Gulf of Mexico is in the background. Note the lakes on the Rio Grande River. Monterrey is near the center of the picture. Field patterns in the lower Rio Grande Valley can easily be identified. The stark, linear roughness of the Sierra Madre Oriental Mountains is the most prominent feature.

  8. Constraints and opportunities for ecological restoration in the Rio Grande Valley, Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are few areas in the United States that have experienced a more precipitous growth than the Lower Rio Grande Valley (RGV) in south Texas, where human populations have almost doubled in the last 20 years. This growth is matched with a rapid proliferation of built environments that is often asso...

  9. Environmental Degradation in a Dependent Region: The Rio Grande Valley of Mexico and Texas.

    ERIC Educational Resources Information Center

    Jones, Richard C.

    1999-01-01

    Traces the interrelationships among dependence, environmental degradation, and human health in the Rio Grande Valley of Mexico and Texas. Presents a case study on environmental factors threatening family health in households located on both sides of the border; the health problems can be overcome by addressing restrictive zoning, health services,…

  10. Poverty and Problems of Development in the Lower Rio Grande Valley of Texas.

    ERIC Educational Resources Information Center

    Miller, Michael V.

    Bounded on the west and south by Mexico and to the east by the Gulf, the Lower Rio Grande Valley of Texas is separated from the nearest U.S. urban center of any size by miles of flat and arid brushland. Its total population of approximately 335,000 is essentially composed of 2 groups--Mexican Americans and Anglos. Although the region is one of the…

  11. 78 FR 1763 - Oranges and Grapefruit Grown in Lower Rio Grande Valley in Texas; Increased Assessment Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-09

    ...; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 906 Oranges and Grapefruit Grown in Lower Rio Grande Valley in Texas; Increased Assessment Rate AGENCY: Agricultural Marketing Service, USDA... Valley in Texas, hereinafter referred to as the ``order.'' The order is effective under the...

  12. Mesohabitats, fish assemblage composition, and mesohabitat use of the Rio Grande silvery minnow over a range of seasonal flow regimes in the Rio Grande/Rio Bravo del Norte, in and near Big Bend National Park, Texas, 2010-11

    USGS Publications Warehouse

    Moring, J. Bruce; Braun, Christopher L.; Pearson, Daniel K.

    2014-01-01

    In 2010–11, the U.S. Geological Survey (USGS), in cooperation with the U.S. Fish and Wildlife Service, evaluated the physical characteristics and fish assemblage composition of mapped river mesohabitats at four sites on the Rio Grande/Rio Bravo del Norte (hereinafter Rio Grande) in and near Big Bend National Park, Texas. The four sites used for the river habitat study were colocated with sites where the U.S. Fish and Wildlife Service has implemented an experimental reintroduction of the Rio Grande silvery minnow (Hybognathus amarus), a federally listed endangered species, into part of the historical range of this species. The four sites from upstream to downstream are USGS station 08374340 Rio Grande at Contrabando Canyon near Lajitas, Tex. (hereinafter the Contrabando site), USGS station 290956103363600 Rio Grande at Santa Elena Canyon, Big Bend National Park, Tex. (hereinafter the Santa Elena site), USGS station 291046102573900 Rio Grande near Ranger Station at Rio Grande Village, Tex. (hereinafter the Rio Grande Village site), and USGS station 292354102491100 Rio Grande above Stillwell Crossing near Big Bend National Park, Tex. (hereinafter the Stillwell Crossing site). In-channel river habitat was mapped at the mesohabitat scale over a range of seasonal streamflows. A late summer (August–September 2010) high-flow regime, an early spring (April–May 2010) intermediate flow regime, and a late spring (May 2011) low-flow regime were the seasonal flows used in the study. River habitat was mapped in the field by using a geographic information system and a Global Positioning System unit to characterize the sites at the mesohabitat scale. Physical characteristics of a subset of mesohabitats in a reach of the Rio Grande at each site were measured during each flow regime and included depth, velocity, type and size of the substrate, and percent embeddedness. Selected water-quality properties (dissolved oxygen, pH, specific conductance, and temperature) of a subset of

  13. Evaluation of canoe surveys for anurans along the Rio Grande in Big Bend National Park, Texas

    USGS Publications Warehouse

    Jung, R.E.; Bonine, K.E.; Rosenshield, M.L.; de la Reza, A.; Raimondo, S.; Droege, S.

    2002-01-01

    Surveys for amphibians along large rivers pose monitoring and sampling problems. We used canoes at night to spotlight and listen for anurans along four stretches of the Rio Grande in Big Bend National Park, Texas, in 1998 and 1999. We explored temporal and spatial variation in amphibian counts and species richness and assessed relationships between amphibian counts and environmental variables, as well as amphibian-habitat associations along the banks of the Rio Grande. We documented seven anuran species, but Rio Grande leopard frogs (Rana berlandieri) accounted for 96% of the visual counts. Chorus surveys along the river detected similar or fewer numbers of species, but orders of magnitude fewer individuals compared to visual surveys. The number of species varied on average by 37% across monthly and nightly surveys. We found similar average coefficients of variation in counts of Rio Grande leopard frogs on monthly and nightly bases (CVs = 42-44%), suggesting that canoe surveys are a fairly precise technique for counts of this species. Numbers of Rio Grande leopard frogs observed were influenced by river gage levels and air and water temperatures, suggesting that surveys should be conducted under certain environmental conditions to maximize counts and maintain consistency. We found significant differences in species richness and bullfrog (Rana catesbeiana) counts among the four river stretches. Four rare anuran species were found along certain stretches but not others, which could represent either sampling error or unmeasured environmental or habitat differences among the river stretches. We found a greater association of Rio Grande leopard frogs with mud banks compared to rock or cliff (canyon) areas and with seepwillow and open areas compared to giant reed and other vegetation types. Canoe surveys appear to be a useful survey technique for anurans along the Rio Grande and may work for other large river systems as well.

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

    USGS Publications Warehouse

    Huber, Caleb G.; Grabowski, Timothy B.; Patino, Reynaldo; Pope, Kevin L.

    2014-01-01

    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.

  15. Historical changes in streamflows, channel morphology, and riparian vegetation of the Rio Grande downstream of Brownsville, Texas

    USGS Publications Warehouse

    Moring, J. Bruce; Setser, Rita

    2000-01-01

    The Rio GrandefRio Bravo drains an area of more than 440,300 square kilometers of Mexico and southwestern United States (Bartlett. 1984). The Rio Grande flows for 3,000 kilometers from its headwaters in the San Juan Mountains of southern Colorado to the Gulf of Mexico downstream of Brownsville, Texas. The "Rio," as it is often called, drains the southern Rocky Mountains of Colorado and northern New Mexico; the vast Chihuahuan Desert of southern New Mexico, northern Mexico, and southwestern Texas; ami the subtropical lower valley of southern Texas (fig. I).

  16. Initial results of environmental monitoring in the Texas Rio Grande Valley.

    PubMed

    Garcia, S S; Ake, C; Clement, B; Huebner, H J; Donnelly, K C; Shalat, S L

    2001-06-01

    Previous studies have suggested that a segment of human disease may be attributable to environmental exposures. These may include exposure to chemicals released from a broad range of natural and man-made sources. The purpose of this study was to develop the sampling methodology and prepare a preliminary database on the presence of various organic chemicals in environmental media in two South Texas counties bordered by the Rio Grande River. A third county, located approximately 150 miles north of the Rio Grande River, was also sampled. The South Texas counties were the focus of study due to an increased incidence of anencephalic births in recent years. The environmental media that was sampled included surface water and sediment from the Rio Grande River and irrigation canals, as well as soil from adjacent cropland and pastures. Samples were collected using United States Geological Survey (USGS) quadrangle maps (7.5'; 1:24,000 scale) to identify the area of interest. At least one sampling location was established in each quadrangle. A pond sampler was used for the collection of surface water samples, while soil was collected with a stainless steel trowel. Sediment samples were collected directly in a glass jar. Solid samples were extracted in a soxhlet extractor using methylene chloride. Organic chemicals were concentrated from water samples on a Sep-Pak cartridge and the organics eluted with methanol/acetonitrile. Extracts were analyzed using GC-MS. All of the surface water samples contained aliphatic hydrocarbons and plasticizers, while soil samples contained aliphatics, plasticizers, pesticides, and industrial estrogens. Specific chemicals detected in environmental samples included atrazine and benzene dicarboxylic acid. Contaminant levels in sediments were generally higher than were detected in other media. The results demonstrate the broad variability of contaminant types and concentrations in environmental samples. Although this study presents only a very

  17. Release and recovery of exotic parasitoids of Bemisia tabaci in the Lower Rio Grande Valley of Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An intensive field program was conducted in the subtropical Lower Rio Grande Valley of Texas (LRGV) to evaluate the establishment of the imported parasitoids of B. tabaci. Thirty populations/species of Eretmocerus and Encarsia parasitoids were mass reared for field release in multiple agricultural c...

  18. Mexican Migrations to the U.S., 1900-1920, with a Focus on the Texas Lower Rio Grande Valley.

    ERIC Educational Resources Information Center

    Miller, Hubert J.

    Migrations from 1900-1920 were analyzed, focusing on the overall pattern of Mexican migrations to the United States during the two decades; migrations to Texas, the major recipient of migrants during the period; and migrations into the lower Rio Grande Valley. Data were based on official registrations either entering the United States or leaving…

  19. School and Public Youth Librarians as Health Information Gatekeepers: Research from the Lower Rio Grande Valley of Texas

    ERIC Educational Resources Information Center

    Lukenbill, Bill; Immroth, Barbara

    2009-01-01

    This study investigated how school and public librarians can become better disseminators of health information and improve health information literacy in small and rural communities in a selected research area. We used the Lower Rio Grande Valley of Texas as our study area, composed of the economically depressed Cameron, Hidalgo, Starr, and…

  20. Susceptibility of redbanded and conchuela stink bugs from the Texas Lower Rio Grande Valley to organophosphate and pyrethroid insecticides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the susceptibility of 2 stink bug species, red banded stink bug (RBSB), Piezodorus guildinii, (Westwood) and conchuela stinkbug, Chlorochroa ligata (Say) collected in the Texas Lower Rio Grande Valley to selected pyrethroid and organophosphate technical grade insecticides. The adult glass ...

  1. Mapping giant reed (Arundo donax) infestations along the Texas-Mexico portion of the Rio Grande using aerial photography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed is an invasive weed throughout the southern half of the United States with the densest stands growing along the coastal rivers of southern California and the Rio Grande in Texas. The objective of this study was to use aerial photography to map giant reed infestations and estimate infested...

  2. Using aerial photography for mapping giant reed infestations along the Texas-Mexico portion of the Rio Grande.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is an invasive weed throughout the southern half of the United States with the densest stands growing along the coastal rivers of southern California and the Rio Grande in Texas. The objective of this study was to use aerial photography to map giant reed infestations and...

  3. Effects of Soil Solarization on Rotylenchulus reniformis in the Lower Rio Grande Valley of Texas.

    PubMed

    Heald, C M; Robinson, A F

    1987-01-01

    Soil solarization was evaluated for control of Rotylenchulus reniformis in the lower Rio Grande Valley of Texas. In field experiments, solarization significantly reduced soil nematode population densities 0-15 cm deep and increased yields of lettuce and cowpea. The length of time required for 90% mortality of nematodes in soil heated under controlled conditions in the laboratory varied from 25 hours to less than 1 hour between 41 and 47 C. Daily exposures of nematode-infested soil to lethal temperatures for sublethal time periods had a cumulative lethal effect. In water, vermiform stages required up to 10 days to recover from sublethal thermal stress. Eggs were similar to juveniles in their sensitivity to high temperatures. Lethal time-temperatures under controlled conditions were in general agreement with field results. PMID:19290112

  4. Trace elements and organic compounds associated with riverbed sediments in the Rio Grande/Rio Bravo basin, Mexico and Texas

    USGS Publications Warehouse

    Lee, R.W.; Wilson, J.T.

    1997-01-01

    In 1991, the Texas Natural Resource Conservation Commission (TNRCC) was mandated by the Texas Clean Rivers Act (Senate Bill 818) to assess water quality of rivers in Texas. Recent efforts to collect information for the assessment of water quality in the Rio Grande/Rio Bravo Basin have involved Federal agencies on both sides of the 1,248-mile U.S.-Mexico border?U.S. Environmental Protection Agency, U.S. Geological Survey (USGS), Secretaria de Desarollo Social (Secretary for Social Development, Mexico), National Water Commission of Mexico, and International Boundary and Water Commission?as well as State and local agencies in a spirit of international cooperation. Substantial efforts have been made to gather data needed to determine the quality of water and ecological status of the Rio Grande/Rio Bravo, especially at sites along the border (fig. 1). The purpose of this report is to assess selected historical data of trace elements and organic compounds in riverbed sediments of the Rio Grande/Rio Bravo, and of the Pecos River and the Arroyo Colorado in Texas.

  5. Solute Sources and Budget for the Rio Grande above El Paso, Texas

    NASA Astrophysics Data System (ADS)

    Hogan, J. F.; Phillips, F. M.; Hendrickx, J. M.

    2001-12-01

    Issues of water quality, especially salinity, limit the use of water resources from the Rio Grande. Identification and quantification of salinity sources is critical for improved river management. In the headwater region salts are typically derived from atmospheric deposition and chemical weathering reactions. Salinity increases during transit may result from both natural (saline groundwater, hydrothermal springs and dissolution of evaporite deposits) and anthropogenic (agricultural return flow and wastewater from sewage treatment plants) sources. These increases are magnified by evapotranspiration (this includes evaporation from open water, transpiration from irrigated agriculture and transpiration from natural riparian areas). With multiple salinity sources and evapotranspiration acting simultaneously, understanding the solute balance for the Rio Grande at a level needed for improved river management is difficult. We have conducted synoptic sampling of the Rio Grande from the headwaters in Colorado to south of El Paso, Texas. Sampling was conducted in January and August of 2000 and 2001. The total dissolved solids content (TDS) of the Rio Grande increases from < 50 mg/L in headwater regions of Colorado to > 2000 mg/L south of El Paso, Texas. The Cl/Br (wt/wt) ratio for river water increases from ~50 in the headwaters (typical for atmospheric deposition) to ~700 in the lower basin. This increase in Cl/Br ratio demonstrates the importance of additional salinity sources. Three end-members are recognized using Cl/Br mixing plots for winter samples: atmospheric deposition, a hydrothermal end-member localized around Truth of Consequences, NM, and a third end-member that may represent groundwater. Samples collected during the summer months are shifted off the winter mixing lines indicating concentration through ET. Increases in salinity were not a simple function of distance downriver, but rather occurred in a series of steps. Some of these steps are correlated with

  6. Species richness, relative abundance, and habitat associations of nocturnal birds along the rio grande in Southern texas

    USGS Publications Warehouse

    Skoruppa, M.K.; Woodin, M.C.; Blacklock, G.

    2009-01-01

    The segment of the Rio Grande between International Falcon Reservoir and Del Rio, Texas (distance ca. 350 km), remains largely unexplored ornithologically. We surveyed nocturnal birds monthly during February-June 1998 at 19 stations along the Rio Grande (n = 6) and at upland stock ponds (n = 13) in Webb County, Texas. We conducted 10-min point counts (n = 89) after sunset and before moonset. Four species of owls and five species of nightjars were detected. Nightjars, as a group, were nearly five limes more abundant (mean number/count = 2.63) than owls (mean number = 0.55). The most, common owl, the great horned owl (Bubo virginianus), had a mean number of 0.25/point count. The mean for elf owls (Micrathene whitneyi) was 0.16/point count. The most common nightjars were the common poorwill (Phalaenoptilus nuttallii; 1.21/point count) and lesser nighthawk (Chordeiles acutipennir, 1.16/point count). Survey sites on the river supported more species (mean = 2.2) than did upland stock ponds (mean = 1.4). However, only one species (common pauraque, Nyctidromus albicollis) showed a preference for the river sites. Our results establish this segment of the Rio Grande in southern Texas as an area of high diversity of nightjars in the United States, matched (in numbers of species) only by southeastern Arizona and southwestern New Mexico.

  7. Anticholinesterase exposure of white-winged doves breeding in lower Rio Grande valley, Texas

    USGS Publications Warehouse

    Tacha, T.C.; Schacht, S.J.; George, R.R.; Hill, E.F.

    1994-01-01

    We studied exposure of breeding white-winged doves (Zenaida asiatica) to anticholinesterase compounds (organophosphorus and carbamate pesticides) in the Lower Rio Grande Valley (LRGV), Texas. Widespread use of organophosphorus pesticides and dove population declines prompted the study. We collected breeding adult doves in May and July 1991 (n = 28) and July 1992 (n = 33) at 6 locations. We used depression of whole-brain cholinesterase (ChE) activity (2 SD below control mean) to detect exposure; values from 4 hand-reared doves fed commercial pigeon chow served as the control. Mean brain ChE activity was lower (P lt 0.027) than the control sample at all 6 locations in 1991; 79% of the birds were diagnostic of exposure ( gt 16.1% ChE depression). Pooled 1992 field samples also were lower (P lt 0.036) than were control samples; doves from 4 of the 6 locations had brain ChE activity below (P lt 0.088) controls. Overall, 39% of 1992 doves were diagnostic of exposure to anticholinesterase compounds. Higher exposure rates in 1991 were probably due to increased use of organophosphorus pesticides. Research is needed documenting effects of sublethal exposure on white-winged dove productivity.

  8. Exposure to insecticides of brushland wildlife within the Lower Rio Grande Valley, Texas, USA

    USGS Publications Warehouse

    Custer, T.W.; Mitchell, C.A.

    1987-01-01

    Brushland wildlife within the Lower Rio Grande Valley of south Texas were studied following applications of eleven insecticides to nearby sugarcane or cotton fields. During the study no wildlife were found dead. Mean brain acetylcholinesterase (AChE) activity of great-tailed grackles (Quiscalus mexicanus) and mourning doves (Zenaida macroura) was significantly lower than controls following application of some organophosphorous insecticides. Brain AChE activity varied significantly among chemicals, days after exposure and application rates. Mean brain AChE activity of white-winged doves (Zenaida asiatica) and three small mammal species was not significantly different than their respective controls following application of insecticides. Mean brain AChE activity of grackles was inhibited significantly more than white-winged doves after application of Bolstar, EPN-methyl parathion, and Azodrin and significantly more than that of mourning doves after applications of Bolstar and EPN-methyl parathion. Our data indicate that there were no adverse effects on most brushland wildlife. Exposure was probably dependent upon use of the agricultural fields as feeding or resting sites and only grackles and mourning doves were regularly present in the fields.

  9. Exposure to insecticides of brushland wildlife within the lower Rio Grande valley Texas USA

    USGS Publications Warehouse

    Custer, T.W.; Mitchell, C.A.

    1987-01-01

    Brushland wildlife within the Lower Rio Grande Valley of south Texas were studied following applications of eleven insecticides to nearby sugarcane or cotton fields. During the study no wildlife were found dead. Mean brain acetycholinesterase (AChE) activity of great-tailed grackles (Quiscalus mexicanus) and mourning doves (Zenaida microura) was significantly lower than controls following application of some organophosphorus insecticides. Brain AChE activity varied significantly among chemicals, days after exposure and lactin rates. Mean brain AChE activity of white-winged doves (Zenaida asiatica) and three small mammals species was not significantly different than their respective control following application of the insecticides. Mean brain AChE activity of grackles was inhibited significantly more than white-winged doves after application of Bolstar, EPN-methyl parathion, and Azodrin and significantly more than that of mourning doves after applications of Bolstar and EPN-methyl parathion. Our data indicate that there were no adverse effects on most brushland wildlife. Exposure was probably dependent upon use of the agricultural fields as feeding or resting site and only grackles and mourning doves were regularly present in the fields.

  10. Chemical control of the Mexican rice borer in the Lower Rio Grande Valley of Texas, 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are no reliably effective controls for the Mexican rice borer on sugarcane in South Texas, and the pest is spreading to rice-growing areas of Texas and Louisiana. A small-plot insecticide test comparing six insecticides was conducted in South Texas during the summer of 2008 to identify compou...

  11. Creating a standardized watersheds database for the Lower Rio Grande/Río Bravo, Texas

    USGS Publications Warehouse

    Brown, J.R.; Ulery, Randy L.; Parcher, Jean W.

    2000-01-01

    This report describes the creation of a large-scale watershed database for the lower Rio Grande/Río Bravo Basin in Texas. The watershed database includes watersheds delineated to all 1:24,000-scale mapped stream confluences and other hydrologically significant points, selected watershed characteristics, and hydrologic derivative datasets.Computer technology allows generation of preliminary watershed boundaries in a fraction of the time needed for manual methods. This automated process reduces development time and results in quality improvements in watershed boundaries and characteristics. These data can then be compiled in a permanent database, eliminating the time-consuming step of data creation at the beginning of a project and providing a stable base dataset that can give users greater confidence when further subdividing watersheds.A standardized dataset of watershed characteristics is a valuable contribution to the understanding and management of natural resources. Vertical integration of the input datasets used to automatically generate watershed boundaries is crucial to the success of such an effort. The optimum situation would be to use the digital orthophoto quadrangles as the source of all the input datasets. While the hydrographic data from the digital line graphs can be revised to match the digital orthophoto quadrangles, hypsography data cannot be revised to match the digital orthophoto quadrangles. Revised hydrography from the digital orthophoto quadrangle should be used to create an updated digital elevation model that incorporates the stream channels as revised from the digital orthophoto quadrangle. Computer-generated, standardized watersheds that are vertically integrated with existing digital line graph hydrographic data will continue to be difficult to create until revisions can be made to existing source datasets. Until such time, manual editing will be necessary to make adjustments for man-made features and changes in the natural landscape

  12. Creating a standardized watersheds database for the lower Rio Grande/Rio Bravo, Texas

    USGS Publications Warehouse

    Brown, Julie R.; Ulery, Randy L.; Parcher, Jean W.

    2000-01-01

    This report describes the creation of a large-scale watershed database for the lower Rio Grande/Rio Bravo Basin in Texas. The watershed database includes watersheds delineated to all 1:24,000-scale mapped stream confluences and other hydrologically significant points, selected watershed characteristics, and hydrologic derivative datasets. Computer technology allows generation of preliminary watershed boundaries in a fraction of the time needed for manual methods. This automated process reduces development time and results in quality improvements in watershed boundaries and characteristics. These data can then be compiled in a permanent database, eliminating the time-consuming step of data creation at the beginning of a project and providing a stable base dataset that can give users greater confidence when further subdividing watersheds. A standardized dataset of watershed characteristics is a valuable contribution to the understanding and management of natural resources. Vertical integration of the input datasets used to automatically generate watershed boundaries is crucial to the success of such an effort. The optimum situation would be to use the digital orthophoto quadrangles as the source of all the input datasets. While the hydrographic data from the digital line graphs can be revised to match the digital orthophoto quadrangles, hypsography data cannot be revised to match the digital orthophoto quadrangles. Revised hydrography from the digital orthophoto quadrangle should be used to create an updated digital elevation model that incorporates the stream channels as revised from the digital orthophoto quadrangle. Computer-generated, standardized watersheds that are vertically integrated with existing digital line graph hydrographic data will continue to be difficult to create until revisions can be made to existing source datasets. Until such time, manual editing will be necessary to make adjustments for man-made features and changes in the natural landscape

  13. Hematozoan parasites of Rio Grande wild turkeys from southern Texas (USA)

    USGS Publications Warehouse

    Castle, Marc D.; Christensen, Beth A.; Rocke, Tonie E.

    1988-01-01

    One hundred twenty-three of 300 blood samples (41%) taken from Rio Grande wild turkeys (Meleagris gallopavo intermedia) from three locations in southern Texas (Welder Wildlife Refuge, Chaparrosa Ranch, and Campo Alegre Ranch) and subinoculated into domestic broad-breasted white turkey poults were positive for a Plasmodium (Novyella) sp. Analysis of blood films from 350 turkeys revealed Haemoproteus meleagridis in 76% of the birds. A significantly greater mean parasite intensity was observed in birds from Welder Wildlife Refuge. Birds from the Campo Alegre Ranch exhibited a significantly higher prevalence of H. meleagridis than birds from Chaparrosa. The Plasmodium sp. was infective for canaries (Serinus canaria), bobwhites (Colinus virginianus), and ring-necked pheasants (Phasianus colchicus), but would not produce infection in white leghorn chickens (Gallus gallus) or Coturnix quail (Coturnix coturnix). Attempts to infect Culex tarsalis and C. pipiens pipiens were unsuccessful. Asexual erythrocytic synchrony was not observed when blood-induced infections were monitored in two domestic turkey poults every 4 hr for 72 hr. Exoerythrocytic stages were not found upon examination of impression smears and tissue samples taken from brain, liver, spleen, kidney, lung, and bone marrow. The Plasmodium sp. is most similar morphologically to three species in the subgenus Novyella, P. hexamerium, P. vaughani, and P. kempi. The most striking similarities are to P. hexamerium, and involve mean merozoite number, erythrocytic schizont location, and vertebrate host susceptibility. It differs from P. vaughani in being able to infect turkeys and in type of parasitized erythrocytes. Differences to P. kempi include mean merozoite number, and ability to infect pheasants, and its inability to develop inC. pipiens and C. tarsalis.

  14. Quality of Shallow Groundwater and Drinking Water in the Mississippi Embayment-Texas Coastal Uplands Aquifer System and the Mississippi River Valley Alluvial Aquifer, South-Central United States, 1994-2004

    USGS Publications Warehouse

    Welch, Heather L.; Kingsbury, James A.; Tollett, Roland W.; Seanor, Ronald C.

    2009-01-01

    The Mississippi embayment-Texas coastal uplands aquifer system is an important source of drinking water, providing about 724 million gallons per day to about 8.9 million people in Texas, Louisiana, Mississippi, Arkansas, Missouri, Tennessee, Kentucky, Illinois, and Alabama. The Mississippi River Valley alluvial aquifer ranks third in the Nation for total withdrawals of which more than 98 percent is used for irrigation. From 1994 through 2004, water-quality samples were collected from 169 domestic, monitoring, irrigation, and public-supply wells in the Mississippi embayment-Texas coastal uplands aquifer system and the Mississippi River Valley alluvial aquifer in various land-use settings and of varying well capacities as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Groundwater samples were analyzed for physical properties and about 200 water-quality constituents, including total dissolved solids, major inorganic ions, trace elements, radon, nutrients, dissolved organic carbon, pesticides, pesticide degradates, and volatile organic compounds. The occurrence of nutrients and pesticides differed among four groups of the 114 shallow wells (less than or equal to 200 feet deep) in the study area. Tritium concentrations in samples from the Holocene alluvium, Pleistocene valley trains, and shallow Tertiary wells indicated a smaller component of recent groundwater than samples from the Pleistocene terrace deposits. Although the amount of agricultural land overlying the Mississippi River Valley alluvial aquifer was considerably greater than areas overlying parts of the shallow Tertiary and Pleistocene terrace deposits wells, nitrate was rarely detected and the number of pesticides detected was lower than other shallow wells. Nearly all samples from the Holocene alluvium and Pleistocene valley trains were anoxic, and the reducing conditions in these aquifers likely result in denitrification of nitrate. In contrast, most samples from the

  15. Sequence stratigraphic model of the Rio Grande Delta, south west Texas: Potential analog for the Niger Delta

    SciTech Connect

    Banfield, L.A.; Anderson, J.B.; Vail, P.R. )

    1996-01-01

    A sequence stratigraphic model developed from the ancient Rio Grande Delta in South West Texas is suggested as an analog for the Niger Delta. The two delta systems are characterized by high sand bedloads, shale diapirism with associated listric normal faulting, and large amounts of tidal and wave influence forming lower coastal plains characterized by swamps and estuaries. The sequence stratigraphic model of the ancient Rio Grande delta is based on approximately 1200 kilometers of single channel, 15 cubic inch water gun data, lithologic descriptions from approximately 25 long cores (28-30 m) located in 17-94 meters water depth, three gamma ray logs, paleontologic data from two cores, and oxygen isotopic data from one core (152 meters in length and located in 94 meters water depth). The combined data indicate that considerable quantities of sand are sequestered on the continental shelf and point sourcing the slope. The Rio Grande sequence stratigraphic model provides an improved understanding of sand deposits on the shelf, of the role of sediment bypass during lowstands, and of the base of slope deposits formed by headward eroding canyons ( ) or channels ( ) located at the shelf break. This information regarding the distribution of sand in the Rio Grande system can provide valuable insight into the reservoir distribution in the Niger system, improving existing reservoir predictions.

  16. Sequence stratigraphic model of the Rio Grande Delta, south west Texas: Potential analog for the Niger Delta

    SciTech Connect

    Banfield, L.A.; Anderson, J.B.; Vail, P.R.

    1996-12-31

    A sequence stratigraphic model developed from the ancient Rio Grande Delta in South West Texas is suggested as an analog for the Niger Delta. The two delta systems are characterized by high sand bedloads, shale diapirism with associated listric normal faulting, and large amounts of tidal and wave influence forming lower coastal plains characterized by swamps and estuaries. The sequence stratigraphic model of the ancient Rio Grande delta is based on approximately 1200 kilometers of single channel, 15 cubic inch water gun data, lithologic descriptions from approximately 25 long cores (28-30 m) located in 17-94 meters water depth, three gamma ray logs, paleontologic data from two cores, and oxygen isotopic data from one core (152 meters in length and located in 94 meters water depth). The combined data indicate that considerable quantities of sand are sequestered on the continental shelf and point sourcing the slope. The Rio Grande sequence stratigraphic model provides an improved understanding of sand deposits on the shelf, of the role of sediment bypass during lowstands, and of the base of slope deposits formed by headward eroding canyons (?) or channels (?) located at the shelf break. This information regarding the distribution of sand in the Rio Grande system can provide valuable insight into the reservoir distribution in the Niger system, improving existing reservoir predictions.

  17. Hydrogeological characterization of a bank filtration experiment site at the Rio Grande, El Paso, Texas, USA

    NASA Astrophysics Data System (ADS)

    Langford, R.; Schulze-Makuch, D.; Pillai, S.; Abdel-Fattah, A.; Widmer, K.

    2003-04-01

    An experiment site was constructed along an artificial channel of the Rio Grande in El Paso, Texas. The experiment was funded by the EPA and is designed to measure the effectiveness of bank filtration in an arid environment. Regionally, the experiment is important because of the hundreds of thousands of people drinking water from shallow wells drilled in close proximity to septic systems. A pumping well was drilled 17 meters from the stream bank and screened from 3.5 to 8 m depth. A cruciform array of observation wells with several multilevel completions allows detection of downstream and vertical movement of water as well as flow from the stream to the well. All of the wells were continuously cored during drilling. Analysis of the cores reveals that the site consists of two stacked channels filled with sand deposited from the meandering Rio Grande. A grid of ground-penetrating radar lines provided three-dimensional coverage between wells and showed bedding to 6.5 m depth. Constant head hydraulic conductivities show that the aquifer consists of two more permeable units separated by the less permeable upper fill of the lower channel complex, with vertical hydraulic conductivities of (1x10-6 to 2x10-6 m/s?). The intervals above and below this interval have the highest vertical conductivities (up to 3.5x10-5 m/s). A multiple pumping and tracer test was conducted using the cruciform array of the field site that consisted of a pumping well, 16 observation wells, and a stream sampling point. The average hydraulic conductivity of the geological media at the field site was about 2 x 10-3 m/s based on pumping test analysis. However, the type curve responses revealed significant heterogeneity of hydraulic conductivity throughout the field site. For the tracer test, bromide and microspheres were used as tracers. Microspheres were used to mimic the behavior of Giardia and Cryptosporidium. The tracers (bromide and microspheres of different sizes and colors) were injected in one

  18. Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

    USGS Publications Warehouse

    Mora, M.A.; Musquiz, D.; Bickham, J.W.; MacKenzie, D.S.; Hooper, M.J.; Szabo, J.K.; Matson, C.W.

    2006-01-01

    We collected adult cave swallows (Petrochelidon fulva) and cliff swallows (P. pyrrhonota) during the breeding seasons in 1999 and 2000 from eight locations along the Rio Grande from Brownsville to El Paso (unless otherwise specified, all locations are Texas, USA) and an out-of-basin reference location. Body mass, spleen mass, hepatosomatic index (HSI), gonadosomatic index (GSI), thyroxine (T4) in plasma, DNA damage measured as the half-peak coefficient of variation of DNA content (HPCV) in blood cells, as well as acetylcholinesterase and butyrylcholinesterase in brain were compared with concentrations of organochlorines, metals, and metalloids in carcasses to determine potential effects of contaminants on swallows during the breeding season. Concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p???-DDE) were significantly greater in swallows from El Paso than in those from most locations, except for Pharr and Llano Grande. All swallows from these three locations had p,p???-DDE concentrations of 3 ??g/g wet weight or greater. Swallows from El Paso either had or shared the highest concentrations of p,p???-DDE, polychlorinated biphenyls, and 13 inorganic elements. Swallows from El Paso exhibited greater spleen mass and HPCV values as well as lower T4 values compared with those from other locations. Thyroxine was a potential biomarker of contaminant exposure in swallows of the Rio Grande, because it was negatively correlated with p,p???-DDE and Se. Spleen mass was positively correlated with selenium and HSI and negatively correlated with body mass, GSI, Mn, and Ni. Overall, the present study suggests that insectivorous birds living in areas of high agricultural and industrial activity along the Rio Grande bioaccumulate environmental contaminants. These contaminants, particularly p,p???-DDE, may be among multiple factors that impact endocrine and hematopoietic function in Rio Grande swallows. ?? 2006 SETAC.

  19. Novel techniques developed to control cattle fever ticks feeding on free-ranging white-tailed deer along the Rio Grande in South Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle fever ticks were eradicated from the southern and southeastern U.S. and California in a campaign that lasted from 1907 through 1943, however, re-introductions across the Rio Grande from Mexico and into South Texas have resulted in extensive efforts to maintain eradication from other parts of ...

  20. Spatial information technologies for climate change impact on ecosystems: detecting and mapping invasive weeds in the Rio Grande River system of south Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wetlands and aquatic ecosystems are vulnerable to climate change. Exotic invasive weeds are a serious problem in the Rio Grande River system of Texas. The river extends 3,040 km from its source in the San Juan Mountains of Colorado to the mouth at the Gulf of Mexico on the United States-Mexico borde...

  1. Application of scintillometry to estimate water use by giant reed (Arndo Donax L.)- A perennial invasive weed along the Rio Grande River near Laredo, Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is a bamboo-like perennial invasive weed from Eurasia presenting a severe threat to agroecosystems and riparian areas in Texas and Mexican portions of the Rio Grande River Basin. It is spreading rapidly by displacing native vegetation. Giant reeds are expected to consume...

  2. Thrips (Thysanoptera: Thripidae) on Cotton in the Lower Rio Grande Valley of Texas: Species Composition, Seasonal Population Dynamics, Damage and Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species composition, population dynamics of thrips on cotton, and their predaceous natural enemies, damage and control, were determined at two different sites during three consecutive seasons from 2005 to 2007 in the Lower Rio Grande Valley (LRGV) of Texas. We observed seven different species of th...

  3. Colonias in the Lower Rio Grande Valley of South Texas: A Summary Report. Lyndon B. Johnson School of Public Affairs, Policy Research Report, Number 18.

    ERIC Educational Resources Information Center

    Haynes, Kingsley E.; And Others

    The Lower Rio Grande Valley of South Texas consists of three counties: Cameron, Hidalgo, and Willacy. Poverty pervades in the Valley, especially in the colonias ("a poor, rural unincorporated community with 20 or more dwelling units, where home ownership is the rule"). Colonia residents are almost exclusively Mexican Americans. Contributing to the…

  4. Chickamauga reservoir embayment study - 1990

    SciTech Connect

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.

    1992-12-01

    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.

  5. Elevated DDE and toxaphene residues in fishes and birds reflect local contamination in the lower Rio Grande Valley, Texas

    USGS Publications Warehouse

    White, D.H.; Mitchell, C.A.; Kennedy, H.D.; Krynitsky, A.J.; Ribick, M.A.

    1983-01-01

    A potential organochlorine pesticide problem was identified near Mission, Texas, by the National Pesticide Monitoring Program. Fish samples from this site have consistently contained elevated levels of DDE since 1968. Surveys were made in 1976, 1978, and 1979 to determine the extent of organochlorine pesticide contamination in fishes and birds of the area. Freshwater fishes of the Arroyo Colorado, a major waterway traversing the lower Rio Grande Valley, were highly contaminated with DDE and toxaphene residues compared to samples from other areas in the Valley; both DDE and toxaphene ranged up to 31.5 ppm wet weight in whole-fish composite samples. In addition, median DDE residues in fish-eating bird carcasses from this area ranged up to 34 ppm wet weight, and 81 ppm in individual specimens. The levels of contaminants detected in fishes and birds were within, or above, the range producing adverse effects in certain species. The major sources of contamination to the Arroyo Colorado system likely stem from past and present use of persistent pesticides on surrounding croplands, and possibly from an abandoned pesticide plant at Mission, Texas.

  6. Elevated DDE and toxaphene residues in fishes and birds reflect local contamination in the lower Rio Grande valley Texas USA

    USGS Publications Warehouse

    White, D.H.; Mitchell, C.A.; Kennedy, H.R.; Krynitsky, A.J.; Ribick, M.A.

    1983-01-01

    A potential organochlorine pesticide problem was identified near Mission, Texas, by the National Park Monitoring Program. Fish samples from this site have consistently contained elevated levels of DDE since 1968. Surveys were made in 1976, 1978, and 1979 to determine the extent of organochlorine pesticide contamination in fishes and birds of the area. Freshwater fishes of Arroyo Colorado, a major waterway traversing the lower Rio Grande Valley, were highly contaminated with DDE and toxaphene residues compared to samples from other areas in the Valley; both DDE and toxaphene ranged up to 31.5 ppm wet wt in whole-fish composite samples. Median DDE residues in fish-eating bird carcasses from this area ranged up to 34 ppm wet wt, and 81 ppm in individual specimens. The levels of contaminants detected in fishes and birds were within, or above, the range producing adverse effects in certain species. The major sources of contamination to the Arroyo Colorado system likely stem from past and present use of persistent pesticides on surrounding croplands, and possibly from an abandoned pesticide plant at Mission, Texas.

  7. A survey of bee species found pollinating watermelons in the Lower Rio Grande Valley of Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a combination of flower traps and visual observations, we surveyed three watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] fields in the Lower Rio Grande Valley to determine what bees inhabit this crop in this region. No managed honey bee (Apis mellifera L.) hives were in any of the fie...

  8. Simple models for embayment flows

    NASA Astrophysics Data System (ADS)

    Gibson, F.; Dalziel, S.

    2003-04-01

    The flow structure in an embayment with a mean external flow has been investigated. The embayment is a relatively quiescent environment separated from the external mean flow by a mixing layer, in a manner analogous to the ventilation of a street canyon in an urban environment. This study aims to improve our knowledge of the exchange between the embayment and the external flow, which is an important mechanism for the transport and dispersion of substances such as nutrients, sediments, heat and pollutants. Understanding of flow in an embayment is therefore vital to the explanation and preservation of its ecology. In an experimental study, a model rectangular embayment was placed in a recirculating flume tank. The aspect ratio and bathymetry of the embayment was varied and the effect on the flow and mixing layer recorded. A neutrally buoyant tracer was added to the flow at various locations to visualise the eddies and the mixing layer. Field experiments in a coastal embayment used an accoustic Doppler current profiler to measure the flow velocities. These measurements demonstrate the existance of a gyre within the bay and support a shear-driven cavity model. In parallel with the experiments and fieldwork, a hierarchy of computer models was used to gain further understanding of the flow. Results from these models are presented alongside the experimental measurements.

  9. Floodplain construction of the Rio Grande at El Paso, Texas, USA: response to Holocene climate change

    NASA Astrophysics Data System (ADS)

    Hall, Stephen A.; Peterson, John A.

    2013-04-01

    The Rio Grande is one of the larger rivers in North America, and the development of its floodplain is related to Holocene climate and climate change. The late Pleistocene through early Holocene channel is characterized by a meander or braided system with lateral cutting and backfilling, resulting in the valley-wide deposition of massive to cross-bedded, fine-to-medium textured sand. The late Pleistocene-early Holocene floodplain is also the sand source for the adjacent Bolson sand sheet. The sand sheet stopped accumulating new sand 5000 yrs ago, an event directly related to the shutting off of the sand supply caused by the deposition of overbank muds that covered and sealed the floodplain surface. During the middle Holocene, the river may have dried intermittently with the floodplain becoming deflated and local sand dunes forming on the floodplain. After 5000 yrs the climate was less arid and the river shifted to a regime of increased flooding and overbank deposition of silt and clay. By 2500 yrs, a late Holocene period of wet climate resulted in further overbank deposition and the formation of a cumulic Mollisol across the floodplain, the Socorro paleosol. The period of wet climate corresponds to the Audubon Neoglacial and active rock glaciers in the southern Rocky Mountains, speleothem growth in nearby caves, and other evidence for wet-cool conditions in the region. After 1000 yrs, the climate became drier, and the deposition and accumulation of overbank muds by the flooding Rio Grande came to a halt. Even though the river has flooded often in historic times, and presumably during late prehistoric times as well, there is little evidence for deposition of overbank sediments on the floodplain since A.D. 1000. Accordingly, the present-day surface of the Lower Valley is ten centuries old. Three channels occur on the US side of the Lower Valley floodplain, and during the past 2500 yrs stream flow has shifted from one to the other by the avulsion process of channel

  10. Mental health screening at temporary military health clinics in low income Hispanic communities within the Rio Grande Valley of Texas.

    PubMed

    Morecook, Robert; Greenstone, James L; Hays, J Ray

    2011-01-01

    Behavioral and mental health problems are not always considered in temporary medical clinics nor are instruments readily available to provide medical practitioners in these settings with information relevant to mental health conditions. This study provided preliminary data on the utility of the Mini Mental Screen in temporary military medical clinics in the Texas Rio Grande Valley. This instrument was administered to individuals who may have behavioral or mental health problems. In a sample of mostly Hispanic patients (N = 75) seen at a temporary medical clinic, 12% were at significant risk of mental health problems, with an additional 9% at moderate risk using published cut-off scores for the risk of such problems. The results for each patient were provided to a medical practitioner who further evaluated the risk, treated the problem, or made a referral. When asked, three of four medical practitioners found that screening data was helpful in their work with patients. One practitioner was concerned that the screening instrument might have too high a false positive rate to be useful. Cultural issues of openness about mental health and behavioral problems need to be considered in such settings. PMID:21957754

  11. Carrizo-upper Wilcox depositional systems and their relation to updip oil production in South Texas

    SciTech Connect

    Hamlin, H.S.

    1983-05-01

    In the Rio Grande embayment of S. Texas, the Carrizo-Upper Wilcox interval consists of 2 fluvial- coastal plain depositional systems that grade downdip into several deltaic complexes. The bedload channel system is dominated by laterally coalesced, stacked fluvial channel sandstones. Shales are minor and laterally discontinuous. The mixed alluvial system consists of a more typical suite of coastal plain facies. Channel sandstones tend to be isolated and surrounded by overbank shales. Total-interval isopach patterns, sandstone geometries, and facies distributions indicate that fluvial systems were converging upon the embayment from the west, northwest, and north. Petroleum production in the updip portion of the Carrizo-Upper Wilcox interval is influenced by the distribution of the depositional systems and their component facies. Although most of the traps are structural, the geometries and internal characteristics of the reservoir sandstones are facies-dependent and affect field size and quality.

  12. Environmental contaminants in blood, hair, and tissues of ocelots from the Lower Rio Grande Valley, Texas, 1986-1997

    USGS Publications Warehouse

    Mora, M.A.; Laack, L.L.; Clare, Lee M.; Sericano, J.; Presley, R.; Gardinali, P.R.; Gamble, L.R.; Robertson, S.; Frank, D.

    2000-01-01

    The ocelot (Felis pardalis) is an endangered neotropical cat distributed within a small range in the Lower Rio Grande Valley (LRGV), in Texas, U.S.A. Studies of the impacts of environmental contaminants in wild cats are few. Approximately one fourth of the estimated population (about 100) of ocelots in the LRGV was sampled to evaluate the impacts of chlorinated pesticides, polychlorinated biphenyls, and trace elements on the population. Hair was collected from 32 ocelots trapped between 1986-1992, and blood was collected from 20 ocelots trapped between 1993-1997. A few blood samples were obtained from individuals recaptured two or three times. Tissue samples from 4 road-killed ocelots were also analyzed. DDE, PCBs, and Hg were some of the most common contaminants detected in hair and blood. Mean Hg levels in hair ranged from 0.5 to 1.25 ??g g-1 dw, Se from 1.5 to 3.48 ??g g-1 dw, and Pb from 0.56 to 26.8 ??g g-1 dw. Mean DDE concentrations in plasma ranged from 0.005 ??g g-1 ww to 0.153 ??g g-1 ww, and PCBs ranged from 0.006 ??g g-1 ww to 0.092 ??g g-1 ww. Mean Hg levels in red blood cells ranged from 0.056 ??g g-1 dw to 0.25 ??g g-1 dw. Concentrations of DDE, PCBs, or Hg, did not increase significantly with age, although the highest concentrations of DDE and Hg were found in older animals. Overall, concentrations of DDE, PCBs, and Hg were low and at levels that currently do not pose any threat to health or survival of the ocelot. This is further supported by good reproduction of the ocelot in the LRGV, where adult females averaged about 1.5 kittens/litter. Thus, it seems that the current major threat to recovery of the ocelot in the LRGV may be habitat loss, although potential impacts of new generation pesticides, such as organophosphorus and carbamate insecticides need further study.The ocelot (Felis pardalis) is an endangered neotropical cat distributed within a small range in the Lower Rio Grande Valley (LRGV), in Texas, U.S.A. Studies of the impacts of

  13. Chlorinated hydrocarbons and biomarkers of exposure in wading birds and fish of the Lower Rio Grande Valley, Texas

    USGS Publications Warehouse

    Wainwright, S.E.; Mora, M.A.; Sericano, J.L.; Thomas, P.

    2001-01-01

    During 1997 we evaluated reproductive success in colonial water birds nesting in the Lower Rio Grande Valley (LRGV), Texas, and correlated success with concentrations of contaminants in eggs. We also measured steroid hormones and gonadosomatic index (GSI) as biomarkers of endocrine effects in common carp (Cyprinus carpio). Nest and fledging success of green herons (Butorides virescens) and great egrets (Ardea alba) were similar to those found in other parts of North America; however, nesting success of black-crowned night-herons (Nycticorax nycticorax) was lower, very likely due to flooding of the nesting area. Except for DDE and toxaphene, all chlorinated pesticides in bird eggs were low and not of concern for negative effects on any of the three species. DDE was highest in green heron eggs and seemed to increase along a geographic gradient from west to east, with eggs from Falcon Reservoir containing low concentrations, and those at Los Indios containing the highest concentrations (approx. 11,000 ng/g WW), near or above the threshold for reproductive impairment. DDE levels in great egrets and black-crowned night-herons were below those that are associated with reproductive impairment. Mean DDE levels in carp at the JAS Farms site were above the threshold level suggested for predator protection. Toxaphene was detected in about 20% of the samples with high levels observed in green heron eggs from Los Indios (mean = 4,402 ng/g WW). These are the highest toxaphene levels reported in bird eggs in the LRGV. Toxaphene levels in fish ranged between 90 and 312 ng/g WW. In general, PCBs in bird eggs and fish tissue were low and at levels not of concern for reproductive effects. The greatest concentrations of testosterone and 11-ketotestosterone were detected in fish from the JAS Farms site, which also had the greatest concentrations of DDE. Increased androgen production and gonad development in fish at this site, relative to Pharr, could be possibly associated with

  14. 78 FR 24329 - Oranges and Grapefruit Grown in Lower Rio Grande Valley in Texas; Increased Assessment Rate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-25

    ... this action was published in the Federal Register on January 9, 2013 (78 FR 1763). Copies of the... rule increases the assessment rate established for the Texas Valley Citrus Committee (Committee) for... price for Texas citrus during the 2010-11 season was around $11.30 per box and total shipments were...

  15. Web application to access U.S. Army Corps of Engineers Civil Works and Restoration Projects information for the Rio Grande Basin, southern Colorado, New Mexico, and Texas

    USGS Publications Warehouse

    Archuleta, Christy-Ann M.; Eames, Deanna R.

    2009-01-01

    The Rio Grande Civil Works and Restoration Projects Web Application, developed by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers (USACE) Albuquerque District, is designed to provide publicly available information through the Internet about civil works and restoration projects in the Rio Grande Basin. Since 1942, USACE Albuquerque District responsibilities have included building facilities for the U.S. Army and U.S. Air Force, providing flood protection, supplying water for power and public recreation, participating in fire remediation, protecting and restoring wetlands and other natural resources, and supporting other government agencies with engineering, contracting, and project management services. In the process of conducting this vast array of engineering work, the need arose for easily tracking the locations of and providing information about projects to stakeholders and the public. This fact sheet introduces a Web application developed to enable users to visualize locations and search for information about USACE (and some other Federal, State, and local) projects in the Rio Grande Basin in southern Colorado, New Mexico, and Texas.

  16. Aquifer tests in the flood-plain alluvium and Santa Fe group at the Rio Grande near Canutillo, El Paso County, Texas

    USGS Publications Warehouse

    Nickerson, Edward L.

    1989-01-01

    An aquifer system consisting of the Rio Grande flood-plain alluvium and Santa Fe Group underlying the southern Mesilla Valley in Dona Ana County, New Mexico and El Paso County, Texas has become an important source of water for both municipal and agricultural uses. Determination of aquifer properties is essential in order to evaluate groundwater potential for increasing water demand and potential streamflow depletion of the Rio Grande due to groundwater development. The aquifer system at the Canutillo well field hydrologic section was divided into a shallow, intermediate, and deep zone based on geohydrologic characteristics. Aquifer properties of specific zones at the test site were determined from a series of multiple-well aquifer tests conducted from December 3, 1985 through January 20, 1986. The Rio Grande is hydraulically connected to the shallow flood-plain alluvium. Water generally occurs within the shallow zone under unconfined conditions, within the intermediate zone under semiconfined conditions, and within the deep zone under confined conditions. (USGS)

  17. Biological studies and field observations in Europe of Lasioptera donacis potential biological control agent of giant reed, Arundo donax, an invasive weed of the Rio Grande Basin of Texas and Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed, Arundo donax L. (Poaceae; Arundinoideae), is a clonal reed grass that is native from the western Mediterranean to India and invasive in North America and other arid temperate/subtropical parts of the world, including the Rio Grande Basin of Texas and Mexico. A biological control of gian...

  18. Landsat sattelite multi-spectral image classification of land cover and land use changes for GIS-based urbanization analysis in irrigation districts of lower Rio Grande Valley of Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Lower Rio Grande Valley in the south of Texas is experiencing rapid increase of population to bring up urban growth that continues influencing on the irrigation districts in the region. This study evaluated the Landsat satellite multi-spectral imagery to provide information for GIS-based urbaniz...

  19. Further Evidence that Zebra Chip Potato Disease in the Lower Rio Grande Valley of Texas is Associated with Bactericera cockerelli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zebra chip (ZC) is an important and emerging potato disease that is causing millions of dollars in losses to both potato producers and processors in the southwestern United States, Texas in particular. This disease is characterized by symptoms that develop in fried chips from infected potato tubers ...

  20. Factors that contribute to Hispanic English Language Learners' high academic performance in high school science in the Rio Grande Valley of Texas: A multicase study

    NASA Astrophysics Data System (ADS)

    Elizondo, Antonio

    The purpose of this multicase study was to discover factors that contribute to Hispanic English language learners' (ELL) high academic performance in high school science in the Rio Grande Valley of Texas. Participants were high school seniors enrolled in college-level classes who had scored commended on the science exit-level Texas Assessment of Knowledge and Skills and ranked toward the top of their class. One student from each of four different high schools in south Texas were selected to participate. Schools identified students meeting the participant criteria and provided consent documents. In this qualitative research study, students were interviewed on three different dates. Administrators and science teachers were also interviewed for triangulation. Significant findings showed that intrinsic qualities were mainly responsible for factors contributing to high academic performance. Hispanic ELL students need meaningful responsibilities to internalize self-esteem and self-efficacy to realize high academic performance. Self-motivation, a contributing factor, provides students with a positive outlook on high academic performance and the ability to defer more immediate undermining rewards. Students expect to contribute to society by helping others. This helps their self-esteem as well as their self-worth and supports high academic performance. Parental and teacher support are critical for high academic performance. Low socioeconomic status alone is not a causal factor for poor academic performance. School administrations should assign willing and enthusiastic teachers as mentors to target students and provide skills to parents that promote, inspire, and motivate students' intrinsic qualities. Future studies should examine different leadership styles that maximize teachers' ability to influence students' high academic performance. Finally, students should be given guidance in setting career goals and demonstrating that high academic achievement is attainable and

  1. Seepage investigations of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2006-13

    USGS Publications Warehouse

    Crilley, D.M.; Matherne, A.M.; Thomas, Nicole; Falk, S.E.

    2013-01-01

    Seepage investigations were conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to 2013 along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of studies conducted from 2006 to 2013 are presented in this report. Seepage investigations were conducted over a period of 1–2 days in February of each year, during low-flow conditions in the non-irrigation season. During the seepage investigations, discharge was measured at as many as 24 sites along the Rio Grande and as many as 20 inflow sites within the study reach. Net seepage gain or loss was computed for each subreach by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be significant when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. Study reaches during 2006 to 2013 ranged from 20.2 to 64 miles in length, and seepage losses ranged from 8.2 ± 3.1 to 47.9 ± 8.2 cubic feet per second.

  2. The quality of our Nation's waters: water quality in the Mississippi embayment-Texas coastal uplands aquifer system and Mississippi River Valley alluvial aquifer, south-central United States, 1994-2008

    USGS Publications Warehouse

    Kingsbury, James A.; Barlow, Jeannie R.; Katz, Brian G.; Welch, Heather L.; Tollett, Roland W.; Fahlquist, Lynne S.

    2015-01-01

    About 8 million people rely on groundwater from the Mississippi embayment—Texas coastal uplands aquifer system for drinking water. The Mississippi River Valley alluvial aquifer also provides drinking water for domestic use in rural areas but is of primary importance to the region as a source of water for irrigation. Irrigation withdrawals from this aquifer are among the largest in the Nation and play a key role in the economy of the area, where annual crop sales total more than $7 billion. The reliance of the region on both aquifers for drinking water and irrigation highlights the importance of long-term management to sustain the availability and quality of these resources.

  3. Seepage investigation of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2014

    USGS Publications Warehouse

    Briody, Alyse C.; Robertson, Andrew J.; Thomas, Nicole

    2016-01-01

    Seepage investigations have been conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to the present (2014) along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of the investigation conducted in 2014 are presented in this report. The 2014 seepage investigation was conducted on February 11, 2014, during the low-flow conditions of the non-irrigation season. During the 2014 investigation, discharge was measured at 23 sites along the main-stem Rio Grande and 19 inflow sites within the study reach. Because of extended drought conditions affecting the basin, many sites along the Rio Grande (17 main-stem and 9 inflow) were observed to be dry in February 2014. Water-quality samples were collected during the seepage investigation at sites with flowing water as part of a long-term monitoring effort in the region.Net seepage gain or loss was computed for each subreach (the interval between two adjacent measurement locations along the river) by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be meaningful when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. The cumulative seepage loss in the 64-mile study reach in 2014 was 16.0 plus or minus 2.9 cubic feet per second.

  4. Crustal structure of the northern mississippi embayment and a comparison with other continental rift zones

    USGS Publications Warehouse

    Mooney, W.D.; Andrews, M.C.; Ginzburg, A.; Peters, D.A.; Hamilton, R.M.

    1983-01-01

    Previous geological and geophysical investigations have suggested that the Mississippi Embayment is the site of a Late Precambrian continental rift that was reactivated in the Mesozoic. New information on the deep structure of the northern Mississippi Embayment, gained through an extensive seismic refraction survey, supports a rifting hypothesis. The data indicate that the crust of the Mississippi Embayment may be characterized by six primary layers that correspond geologically to unconsolidated Mesozoic and Tertiary sediments (1.8 km/s), Paleozoic carbonate and clastic sedimentary rocks (5.9 km/s), a low-velocity layer of Early Paleozoic sediments (4.9 km/s), crystalline upper crust (6.2 km/s), lower crust (6.6 km/s), modified lower crust (7.3 km/s), and mantle. Average crustal thickness is approximately 41 km. The presence and configuration of the low-velocity layer provide new evidence for rifting in the Mississippi Embayment. The layer lies within the northeast-trending upper-crustal graben reported by Kane et al. (1981), and probably represents marine shales deposited in the graben after rifting. The confirmation and delineation of a 7.3 km/s layer, identified in previous studies, implies that the lower crust has been altered by injection of mantle material. Our results indicate that this layer reaches a maximum thickness in the north-central Embayment and thins gradually to the southeast and northwest, and more rapidly to the southwest along the axis of the graben. The apparent doming of the 7.3 km/s layer in the north-central Embayment suggests that rifting may be the result of a triple junction located in the Reelfoot Basin area. The crustal structure of the Mississippi Embayment is compared to other continental rifts: the Rhinegraben, Limagnegraben, Rio Grande Rift, Gregory Rift, and the Salton Trough. This comparison suggests that alteration of the lower crust is a ubiquitous feature of continental rifts. ?? 1983.

  5. Contaminant exposure of willets feeding in agricultural drainages of the Lower Rio Grande Valley of South Texas.

    PubMed

    Custer, T W; Mitchell, C A

    1991-02-01

    Willets (Catoptrophorus semipalmatus) were collected in June and August 1986 at the outlets of two agricultural drainages into the Lower Laguna Madre of South Texas and at two other Texas coastal sites. Mean liver concentration of arsenic was higher in August than June. Over 20% of the livers had arsenic concentrations elevated above a suggested background level of 5.0 ppm dry weight (DW), but concentrations (maximum 15 ppm) were below those associated with acute toxicity. Selenium concentration in livers varied from 2.3 to 8.3 ppm DW for all locations and represented background levels. Mercury concentrations in livers for all locations (means = 2.0 to 3.4, maximum 17 ppm DW) were below those associated with avian mortality and similar to levels found in other estuarine/marine birds. DDE in carcasses was higher in adults (mean = 1.0 ppm wet weight) than juveniles (0.2 ppm), and higher in August (1.0 ppm) than June (0.5 ppm); however, DDE concentrations were generally at background levels. Based on brain cholinesterase activity, willets were not recently exposed to organophosphate pesticides. PMID:24241892

  6. Contaminant exposure of willets feeding in agricultural drainages of the lower Rio Grande valley of south Texas

    USGS Publications Warehouse

    Custer, T.W.; Mitchell, C.A.

    1991-01-01

    Willets (Catoptrophorus semipalmatus) were collected in June and August 1986 at the outlets of two agricultural drainages into the Lower Laguna Madre of South Texas and at two other Texas coastal sites. Mean liver concentration of arsenic was higher in August than June. Over 20% of the livers had arsenic concentrations elevated above a suggested background level of 5.0 ppm dry weight (DW), but concentrations (maximum 15 ppm) were below those associated with acute toxicity. Selenium concentration in livers varied from 2.3 to 8.3 ppm DW for all locations and represented background levels. Mercury concentrations in livers for all locations (means = 2.0 to 3.4, maximum 17 ppm DW) were below those associated with avian mortality and similar to levels found in other estuarine/marine birds. DDE in carcasses was higher in adults (mean = 1.0 ppm wet weight) than juveniles (0.2 ppm), and higher in August (1.0 ppm) than June (0.5 ppm); however, DDE concentrations were generally at background levels. Based on brain cholinesterase activity, willets were not recently exposed to organophosphate pesticides.

  7. Potential effects of environmental contaminants on P450 aromatase activity and DNA damage in swallows from the Rio Grande and Somerville, Texas

    USGS Publications Warehouse

    Sitzlar, M.A.; Mora, M.A.; Fleming, J.G.W.; Bazer, F.W.; Bickham, J.W.; Matson, C.W.

    2009-01-01

    Cliff swallows (Petrochelidon pyrrhonota) and cave swallows (P. fulva) were sampled during the breeding season at several locations in the Rio Grande, Texas, to evaluate the potential effects of environmental contaminants on P450 aromatase activity in brain and gonads and DNA damage in blood cells. The tritiated water-release aromatase assay was used to measure aromatase activity and flow cytometry was used to measure DNA damage in nucleated blood cells. There were no significant differences in brain and gonadal aromatase activities or in estimates of DNA damage (HPCV values) among cave swallow colonies from the Lower Rio Grande Valley (LRGV) and Somerville. However, both brain and gonadal aromatase activities were significantly higher (P < 0.05) in male cliff swallows from Laredo than in those from Somerville. Also, DNA damage estimates were significantly higher (P < 0.05) in cliff swallows (males and females combined) from Laredo than in those from Somerville. Contaminants of current high use in the LRGV, such as atrazine, and some of the highly persistent organochlorines, such as toxaphene and DDE, could be potentially associated with modulation of aromatase activity in avian tissues. Previous studies have indicated possible DNA damage in cliff swallows. We did not observe any differences in aromatase activity or DNA damage in cave swallows that could be associated with contaminant exposure. Also, the differences in aromatase activity and DNA damage between male cliff swallows from Laredo and Somerville could not be explained by contaminants measured at each site in previous studies. Our study provides baseline information on brain and gonadal aromatase activity in swallows that could be useful in future studies. ?? 2008 Springer Science+Business Media, LLC.

  8. Streamflow gains and losses and selected water-quality observations in five subreaches of the Rio Grande/Rio Bravo del Norte from near Presidio to Langtry, Texas, Big Bend area, United States and Mexico, 2006

    USGS Publications Warehouse

    Raines, Timothy H.; Turco, Michael J.; Connor, Patrick J.; Bennett, Jeffery B.

    2012-01-01

    Few historical streamflow and water-quality data are available to characterize the segment of the Rio Grande/Rio Bravo del Norte (hereinafter Rio Grande) extending from near Presidio to near Langtry, Texas. The U.S. Geological Survey, in cooperation with the National Park Service and the Texas Commission on Environmental Quality, collected water-quality and streamflow data from the Rio Grande from near Presidio to near Langtry, Texas, to characterize the streamflow gain and loss and selected constituent concentrations in a 336.3-mile reach of the Rio Grande from near Presidio to near Langtry, Texas. Streamflow was measured at 38 sites and water-quality samples were collected at 20 sites along the Rio Grande in February, March, and June 2006. Streamflow gains and losses over the course of the stream were measured indirectly by computing the differences in measured streamflow between sites along the stream. Water-quality data were collected and analyzed for salinity, dissolved solids, major ions, nutrients, trace elements, and stable isotopes. Selected properties and constituents were compared to available Texas Commission on Environmental Quality general use protection criteria or screening levels. Summary statistics of selected water-quality data were computed for each of the five designated subreaches. Streamflow gain and loss and water-quality constituent concentration were compared for each subreach, rather than the entire segment because of the temporal variation in sample collection caused by controlled releases upstream. Subreach A was determined to be a losing reach, and subreaches B, C, D, and E were determined to be gaining reaches. Compared to concentrations measured in upstream subreaches, downstream subreaches exhibited evidence of dilution of selected constituent concentrations. Subreaches A and B had measured total dissolved solids, chloride, and sulfate exceeding the Texas Commission on Environmental Quality general use protection criteria

  9. Fluvial depositional systems of Carrizo-Upper Wilcox in south Texas

    SciTech Connect

    Hamlin, H.S.

    1983-09-01

    In the Rio Grande embayment of south Texas, the Carrizo-upper Wilcox interval (Eocene) consists of two sand-rich coastal plain fluvial depositional systems that grade basinward into several deltaic complexes. The bedload channel system is dominated by multi-story, multi-lateral, fluvial, channel-fill sandstones. This system is typically > 90% sandstone. Shales are thin and laterally discontinuous, the remnants of abandoned channel fills. Bedload channel sandstones dominate the major fluvial axes and form the depositional framework of the interval. The mixed alluvial system consists of a more typical suite of coastal plain facies. Mixed-load channel-fill sandstones tend to be isolated and surrounded by overbank shales and thin sandstones. Crevasse splay and lacustrine facies occur in the flood-plain area. Total-interval isopach patterns, sandstone geometries, and depositional systems distributions indicate that fluvial sediment input was converging upon the embayment from the west, northwest, and north. Economically, the Carrizo-upper Wilcox of south Texas has a three-fold significance. The updip Carrizo sandstone is a major source of fresh groundwater, includes several large oil fields, and also contains deposits of uranium minerals. The downdip upper Wilcox trend is an area of active hydrocarbon exploration.

  10. Evaluation of soil sustainability along the Rio Grande in West Texas: changes in salt loading and organic nutrients due to farming practices

    NASA Astrophysics Data System (ADS)

    Cox, C. L.; Ganjegunte, G.; Borrok, D. M.; Lougheed, V.; Ma, L.; Jin, L.

    2011-12-01

    thus have higher salt loading, and that Cotton has a higher clay content. The EC values continuously increase from irrigation water to soil waters, suggesting that as water travels through the soil profile it increases in salinity. Consistent with this observation, cation concentrations in soil waters increased with depth. Therefore, the salts within the soils are mobilized during irrigation. 5TE sensors at all three depths in the field showed spikes in EC, and soil moisture during each period of flood irrigation. Data also suggests a lower bulk EC between irrigation periods which might result from a lower soil moisture content which doesn't solublize the salts. The carbonate- and gypsum- rich soils and surface water in the Rio Grande Basin change with intensity and amount of irrigation, addition of fertilizers, and other agricultural practices. Results from this project contribute to our understanding of salt loading and nutrient cycling in the vulnerable area of the Rio Grande Valley in West Texas.

  11. Comparative Phylogeography of Mississippi Embayment Fishes

    PubMed Central

    Egge, Jacob J. D.; Hagbo, Taylor J.

    2015-01-01

    The Mississippi Embayment is a prominent physiographic feature of eastern North America consisting of primarily lowland aquatic habitats and a fish fauna that is largely distinct from nearby highland regions. Numerous studies have demonstrated that both pre-Pleistocene and Pleistocene events have had a strong influence on the distributions and relationships of highland fishes in eastern North America. However, the extent to which these same events affected Embayment distributed taxa remains largely unexplored. The purpose of this study was to investigate the relative roles of pre-Pleistocene and Pleistocene events in shaping phylogeographic relationships of four stream dwelling fishes in the Mississippi Embayment. Molecular genetic analyses of the mitochondrial gene cytochrome b were performed for three ictalurid catfish species (Noturus miurus, n = 67; Noturus hildebrandi, n = 93, and Noturus phaeus, n = 44) and one minnow species (Cyprinella camura, n = 78), all distributed in tributary streams of the Mississippi Embayment. Phylogenetic relationships and divergence times among haplotypes for each species were estimated using maximum likelihood and Bayesian methods. Phylogenetic analyses recovered 6 major haplotype clades within N. miurus, 5 within N. hildbrandi, 8 within N. phaeus, and 8 within C. camura. All three Noturus species show a high degree of isolation by drainage, which is less evident in C. camura. A clade of haplotypes from tributaries in the southern portion of the Mississippi Embayment was consistently recovered in all four species. Divergence times among clades spanned the Pleistocene, Pliocene, and Miocene. Novel relationships presented here for C. camura and N. phaeus suggest the potential for cryptic species. Pre-Pleistocene and Pleistocene era sea level fluctuations coincide with some divergence events, but no single event explains any common divergence across all taxa. Like their highland relatives, a combination of both pre-Pleistocene and

  12. Comparative phylogeography of Mississippi embayment fishes.

    PubMed

    Egge, Jacob J D; Hagbo, Taylor J

    2015-01-01

    The Mississippi Embayment is a prominent physiographic feature of eastern North America consisting of primarily lowland aquatic habitats and a fish fauna that is largely distinct from nearby highland regions. Numerous studies have demonstrated that both pre-Pleistocene and Pleistocene events have had a strong influence on the distributions and relationships of highland fishes in eastern North America. However, the extent to which these same events affected Embayment distributed taxa remains largely unexplored. The purpose of this study was to investigate the relative roles of pre-Pleistocene and Pleistocene events in shaping phylogeographic relationships of four stream dwelling fishes in the Mississippi Embayment. Molecular genetic analyses of the mitochondrial gene cytochrome b were performed for three ictalurid catfish species (Noturus miurus, n = 67; Noturus hildebrandi, n = 93, and Noturus phaeus, n = 44) and one minnow species (Cyprinella camura, n = 78), all distributed in tributary streams of the Mississippi Embayment. Phylogenetic relationships and divergence times among haplotypes for each species were estimated using maximum likelihood and Bayesian methods. Phylogenetic analyses recovered 6 major haplotype clades within N. miurus, 5 within N. hildbrandi, 8 within N. phaeus, and 8 within C. camura. All three Noturus species show a high degree of isolation by drainage, which is less evident in C. camura. A clade of haplotypes from tributaries in the southern portion of the Mississippi Embayment was consistently recovered in all four species. Divergence times among clades spanned the Pleistocene, Pliocene, and Miocene. Novel relationships presented here for C. camura and N. phaeus suggest the potential for cryptic species. Pre-Pleistocene and Pleistocene era sea level fluctuations coincide with some divergence events, but no single event explains any common divergence across all taxa. Like their highland relatives, a combination of both pre-Pleistocene and

  13. Texas Greenup

    NASA Technical Reports Server (NTRS)

    2007-01-01

    June 2007 was one of the wettest Junes on record for the state of Texas. Starting in late May, a string of low-pressure systems settled in over the U.S. Southern Plains and unleashed weeks of heavy to torrential rain. During the final week of June, much of Texas, Oklahoma, and Kansas received more than 330 percent of their average rainfall, said the National Climatic Data Center. The widespread heavy rain brought deadly floods to the entire region. On July 6, the Associated Press reported that every major river basin in Texas was at flood stage, an event that had not occurred since 1957. In addition to causing floods, the rains stimulated plant growth. The grassy, often arid, plains and plateaus of northern Mexico (bottom left), Texas (center), and New Mexico (top, left of center) burst to life with dense vegetation as this vegetation anomaly image shows. Regions where plants were growing more quickly or fuller than average are green, while areas where growth is below average are brown. Most of Texas is green, with a concentrated deep green, almost black, spot where vegetation growth was greatest. This area of western Texas is where the Pecos River flows out of New Mexico and heads southeast to the Rio Grande. In the darkest areas, vegetation was more than 100 percent above average. The brown spots in northeastern Texas and Oklahoma (top, right of center) may be areas where persistent clouds or water on the ground are hiding the plants from the satellite's view. Plants may also be growing less than average if swamped by too much rain. The image was made with data collected by the SPOT satellite between June 11 and June 20, 2007. NASA imagery created by Jesse Allen, Earth Observatory, using SPOT data provided courtesy of the USDA Foreign Agricultural Service and processed by Jennifer Small and Assaf Anyamba of the GIMMS Group at NASA GSFC.

  14. Rio Grande Wetbacks: Mexican Migrant Workers.

    ERIC Educational Resources Information Center

    Norquest, Carrol

    Farmers in the Lower Rio Grande Valley of Texas saw a rise of wetback labor in the 1930s and 40s. The wetback laborers were Mexicans who had crossed the Rio Grande and were in the United States illegally to work. Carrol Norquest, a farmer in the Lower Rio Grande Valley, employed wetbacks regularly. In this book, Mr. Norquest writes about the…

  15. An integrated geological and geophysical study of the Uinta Mountains, Utah, Colorado and a geophysical study on Tamarix in the Rio Grande River basin, West Texas

    NASA Astrophysics Data System (ADS)

    Khatun, Salma

    2008-07-01

    comprehensive picture of the structures in the study area. These models show that the Uinta uplift is a single sedimentary block with numerous thrust faults on the northern and southern flanks of the uplift. These models also reveal the fact that the thickness of the crust is quite variable in the study area. This is also supported by the crustal thickness map constructed for this study from seismic and receiver function information. Magnetic maps show that the Proterozoic sedimentary package known as Uinta Mountain Group extends into the Basin and Range and indicates its link with the ancient rift margin in the Western United States. Findings of this research are correlated to earlier studies and placed in a broader context. Finally an analogy is made between the Uinta aulacogen, the Southern Oklahoma aulacogen and the Dniepr-Donets aulacogen in Ukraine. This discussion focuses light on the mechanism that led to the Uinta's development from a failed rift to an uplift. Part two of this research examined the effect of saltcedar (Tamarix sp) on water and soil properties in the Rio Grande River valley in West Texas. Tamarix is a woody phreatophyte (water-loving plant) common in riparian habitats. The presence of Tamarix in a river system raises concerns about its effect on water quality because it can increase the salinity of water and surrounding soil and it reduces stream flow. Geophysical electrical techniques were used to track soil salinity and moisture changes caused by Tamarix, as well as to determine how soil salinity and moisture properties are altered when Tamarix is eradicated from the region. These techniques allowed more rapid in-situ assessment of the soil properties than the conventional method of removing soil and water samples for analysis. This study was focused on the influence of Tamarix on soil properties and hydrology at the subsurface at four sites in the Rio Bosque Wetlands Park, El Paso, Texas Two sites had flourishing Tamarix and two others were areas

  16. An integrated geological and geophysical study of the Uinta Mountains, Utah, Colorado and a geophysical study on Tamarix in the Rio Grande River basin, West Texas

    NASA Astrophysics Data System (ADS)

    Khatun, Salma

    2008-07-01

    comprehensive picture of the structures in the study area. These models show that the Uinta uplift is a single sedimentary block with numerous thrust faults on the northern and southern flanks of the uplift. These models also reveal the fact that the thickness of the crust is quite variable in the study area. This is also supported by the crustal thickness map constructed for this study from seismic and receiver function information. Magnetic maps show that the Proterozoic sedimentary package known as Uinta Mountain Group extends into the Basin and Range and indicates its link with the ancient rift margin in the Western United States. Findings of this research are correlated to earlier studies and placed in a broader context. Finally an analogy is made between the Uinta aulacogen, the Southern Oklahoma aulacogen and the Dniepr-Donets aulacogen in Ukraine. This discussion focuses light on the mechanism that led to the Uinta's development from a failed rift to an uplift. Part two of this research examined the effect of saltcedar (Tamarix sp) on water and soil properties in the Rio Grande River valley in West Texas. Tamarix is a woody phreatophyte (water-loving plant) common in riparian habitats. The presence of Tamarix in a river system raises concerns about its effect on water quality because it can increase the salinity of water and surrounding soil and it reduces stream flow. Geophysical electrical techniques were used to track soil salinity and moisture changes caused by Tamarix, as well as to determine how soil salinity and moisture properties are altered when Tamarix is eradicated from the region. These techniques allowed more rapid in-situ assessment of the soil properties than the conventional method of removing soil and water samples for analysis. This study was focused on the influence of Tamarix on soil properties and hydrology at the subsurface at four sites in the Rio Bosque Wetlands Park, El Paso, Texas Two sites had flourishing Tamarix and two others were areas

  17. Impact of the biological control agent, Tetramesa romana (Hymenoptera: Eurytomidae) on Arundo donax (Poaceae: Arundinoideae) along the Rio Grande River in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Five years post release of 1.2 million arundo wasps, Tetramesa romana, into the riparian habitats of the lower Rio Grande River; changes in the health the invasive weed, Arundo donax, giant reed have been documented. These changes in plant attributes are fairly consistent along the 558 river miles b...

  18. Sequence stratigraphy and hydrocarbon exploration: updip Wilcox trend in south Texas

    SciTech Connect

    Smith, W.M.; Breyer, J.A.

    1988-02-01

    Five unconformity-bounded depositional sequences occur in the sub-surface lower and middle Wilcox in south Texas. All of the sequences are oil and gas productive in the updip Wilcox trend. Forty-four class D and E oil and gas fields, with a combined cumulative production of over 40 million bbl of oil and 12,000 million ft/sup 3/ of gas, produce from the lower and middle Wilcox in a 4,000-mi/sup 2/ area in the northern part of the Rio Grande embayment. Much of the established production is from sands associated with the basal unconformity of each sequence. Twenty-four of the 38 fields producing from Sequence B produce from the basal sand in the sequence. Most of the fields occur in areas of relatively low sand percent. The low-sand areas occur in different places in different sequences because the locus of sand accumulation shifted during the deposition of the Wilcox Group. The potentially productive low-sand areas are not apparent on a sand percent map for the composite lower and middle Wilcox. The techniques they used to delineate potential productive areas in the updip Wilcox trend in south Texas can be applied throughout much of the Gulf Coast basin and in other petroleum provinces with terrigenous clastic depositional systems as well.

  19. Water resources data - Texas water year 2002 : Volume 5. Guadalupe River basin, Nueces River basin, Rio Grande basin, and intervening coastal basins

    USGS Publications Warehouse

    Gandara, S.C.

    2003-01-01

    Water-resources data for the 2002 water year for Texas are presented in six volumes and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 82 gaging stations; stage only at 6 gaging stations; stage and contents at 8 lakes and reservoirs; water quality at 25 gaging stations; and data for 30 partial-record stations comprised of 2 flood-hydrograph, 6 low-flow, 4 crest-stage, and 18 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  20. Water Resources Data Texas Water Year 2003, Volume 5. Guadalupe River Basin, Nueces River Basin, Rio Grande Basin, and Intervening Coastal Basins

    USGS Publications Warehouse

    Gandara, S.C.

    2004-01-01

    Water-resources data for the 2003 water year for Texas are presented in six volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 84 gaging stations; stage only at 6 gaging stations; stage and contents at 6 lakes and reservoirs; water quality at 28 gaging stations; and data for 18 partial-record stations comprised of 1 flood-hydrograph, 10 low-flow, 4 crest-stage, and 3 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  1. Water resources data - Texas water year 2001 : Volume 5. Guadalupe River basin, Nueces River basin, Rio Grande basin, and intervening coastal basins

    USGS Publications Warehouse

    Gandara, S.C.

    2002-01-01

    Water-resources data for the 2001 water year for Texas are presented in six volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 77 gaging stations; stage only at 4 gaging stations; stage and contents at 5 lakes and reservoirs; water quality at 27 gaging stations; and data for 23 partial-record stations comprised of 3 flood-hydrograph, 8 low-flow, 4 crest-stage, and 3 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  2. Water Resources Data - Texas Water Year 2000, Volume 5. Guadalupe River Basin, Nueces River Basin, Rio Grande Basin, and Intervening Coastal Basins

    USGS Publications Warehouse

    Gandara, S.C.; Gibbons, W.J.; Barbie, D.L.

    2001-01-01

    Water-resources data for the 2000 water year for Texas are presented in six volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 71 gaging stations; stage only at 4 gaging stations; stage and contents at 4 lakes and reservoirs; water quality at 29 gaging stations; and data for 23 partial-record stations comprised of 3 flood-hydrograph, 10 low-flow, 6 crest-stage, and 4 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  3. Water Resources Data, Texas Water Year 1998, Volume 3. Colorado River Basin, Lavaca River Basin, Guadalupe River Basin, Nueces River Basin, Rio Grande Basin, and Intervening Coastal Basins

    USGS Publications Warehouse

    Gandara, S.C.; Gibbons, W.J.; Andrews, F.L.; Barbie, D.L.

    1999-01-01

    Water-resources data for the 1998 water year for Texas are presented in four volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 3 contains records for water discharge at 126 gaging stations; stage only at 3 gaging stations; stage and contents at 15 lakes and reservoirs; water quality at 62 gaging stations; and data for 35 partial-record stations comprised of 8 flood-hydrograph, 14 low-flow, and 18 creststage, and 5 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  4. Water Resources Data - Texas Water Year 1999, Volume 5. Guadalupe River Basin, Nueces River Basin, Rio Grande Basin, and Intervening Coastal Basins

    USGS Publications Warehouse

    Gandara, S.C.; Gibbons, W.J.; Barbie, D.L.; Jones, R.E.

    2000-01-01

    Water-resources data for the 1999 water year for Texas are presented in six volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 76 gaging stations; stage only at 1 gaging stations; stage and contents at 4 lakes and reservoirs; water quality at 38 gaging stations; and data for 30 partial-record stations comprised of 3 flood-hydrograph, 14 low-flow, and 8 crest-stage, and 5 miscellaneous stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  5. Water resources data Texas, water year 2004, volume 5. Guadalupe River basin, Nueces River basin, Rio Grande basin, and intervening coastal basins

    USGS Publications Warehouse

    Long, Susan C. Aragon; Reece, Brian D.; Eames, Deanna R.

    2005-01-01

    Water-resources data for the 2004 water year for Texas are presented in six volumes, and consist of records of stage, discharge, and water quality of streams and canals; stage, contents, and water-quality of lakes and reservoirs; and water levels and water quality of ground-water wells. Volume 5 contains records for water discharge at 86 gaging stations; stage only at 5 gaging stations; elevation at 3 lakes and reservoirs; content at 4 lakes and reservoirs;and water quality at 24 gaging stations. Also included are data for 16 partial-record stations comprised of 1 flood-hydrograph, 11 low-flow, and 4 crest-stage stations. Also included are lists of discontinued surface-water discharge or stage-only stations and discontinued surface-water-quality stations. Additional water data were collected at various sites, not part of the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating Federal, State, and local agencies in Texas. Records for a few pertinent stations in the bordering States also are included.

  6. Usage and administration manual for a geodatabase compendium of water-resources data-Rio Grande Basin from the Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas, 1889-2009

    USGS Publications Warehouse

    Burley, Thomas E.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Interstate Stream Commission, developed a geodatabase compendium (hereinafter referred to as the 'geodatabase') of available water-resources data for the reach of the Rio Grande from Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas. Since 1889, a wealth of water-resources data has been collected in the Rio Grande Basin from Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas, for a variety of purposes. Collecting agencies, researchers, and organizations have included the U.S. Geological Survey, Bureau of Reclamation, International Boundary and Water Commission, State agencies, irrigation districts, municipal water utilities, universities, and other entities. About 1,750 data records were recently (2010) evaluated to enhance their usability by compiling them into a single geospatial relational database (geodatabase). This report is intended as a user's manual and administration guide for the geodatabase. All data available, including water quality, water level, and discharge data (both instantaneous and daily) from January 1, 1889, through December 17, 2009, were compiled for the study area. A flexible and efficient geodatabase design was used, enhancing the ability of the geodatabase to handle data from diverse sources and helping to ensure sustainability of the geodatabase with long-term maintenance. Geodatabase tables include daily data values, site locations and information, sample event information, and parameters, as well as data sources and collecting agencies. The end products of this effort are a comprehensive water-resources geodatabase that enables the visualization of primary sampling sites for surface discharges, groundwater elevations, and water-quality and associated data for the study area. In addition, repeatable data processing scripts, Structured Query Language queries for loading prepared data sources, and a detailed process for refreshing all data in the

  7. Design and Compilation of a Geodatabase of Existing Salinity Information for the Rio Grande Basin, from the Rio Arriba-Sandoval County Line, New Mexico, to Presidio, Texas, 2010

    USGS Publications Warehouse

    Shah, Sachin D.; Maltby, David R., II

    2010-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, compiled salinity-related water-quality data and information in a geodatabase containing more than 6,000 sampling sites. The geodatabase was designed as a tool for water-resource management and includes readily available digital data sources from the U.S. Geological Survey, U.S. Environmental Protection Agency, New Mexico Interstate Stream Commission, Sustainability of semi-Arid Hydrology and Riparian Areas, Paso del Norte Watershed Council, numerous other State and local databases, and selected databases maintained by the University of Arizona and New Mexico State University. Salinity information was compiled for an approximately 26,000-square-mile area of the Rio Grande Basin from the Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas. The geodatabase relates the spatial location of sampling sites with salinity-related water-quality data reported by multiple agencies. The sampling sites are stored in a geodatabase feature class; each site is linked by a relationship class to the corresponding sample and results stored in data tables.

  8. Grand Canyon

    Atmospheric Science Data Center

    2014-05-15

    article title:  The Grand Canyon     View Larger Image Northern Arizona and the Grand Canyon are captured in this pair of Multi-angle Imaging SpectroRadiometer ... formats available at JPL December 31, 2000 - Grand Canyon and Lake Powell. project:  MISR ...

  9. Status of fish communities in the Rio Grande, Big Bend National Park, Texas - comparison before and after Spring 2003 period of low flow

    USGS Publications Warehouse

    Moring, J. Bruce

    2005-01-01

    During 2003–04 the U.S. Geological Survey, in cooperation with the National Park Service, re-evaluated the status of fish communities in three reaches of the Rio Grande in Big Bend National Park that originally were evaluated when the three reaches were established for study in 1999. The objective was to determine whether there were measurable differences between 1999 and 2003–04 (referred to as 2004) fish community status that likely are attributable to a rare 58-day period of low flow (less than 1 cubic meter per second) in spring 2003 at the Johnson Ranch gaging station on the Rio Grande in Big Bend National Park. The total number of fish species collected at all three sites (Boquillas, Johnson Ranch, and Santa Elena) in 1999 was greater than in 2004. The number of fish species collected at the Boquillas site in 1999 (10) was twice that collected in 2004; the number of species collected at the Johnson Ranch site in 1999 (nine) was almost twice that collected in 2004 (five). In contrast, the numbers at the Santa Elena site were nearly the same, 15 species in 1999, 14 in 2004. Percent community similarity for the Boquillas site is 8.04, for the Johnson Ranch site, 6.65, and for the Santa Elena site, 47.6, which indicates considerably more similarity between the 1999 and 2004 fish communities at the Santa Elena site than for the Boquillas and Johnson Ranch sites. At the Boquillas and Johnson Ranch sites, the fish communities shifted from small minnow (Cyprinidae) dominated in 1999 to largely gar (Lepisosteidae) and catfish (Ictaluridae) dominated in 2004. In contrast, no such shift occurred at the Santa Elena site between 1999 and 2004. Differences in flow conditions between the two downstream sites and the Santa Elena site might account for the dissimilar findings. The findings of the study provide some evidence that the spring 2003 period of low flow affected fish communities, but the findings are not definitive as other factors such as increased salinity

  10. Plant water use characteristics of five dominant shrub species of the Lower Rio Grande Valley, Texas, USA: implications for shrubland restoration and conservation.

    PubMed

    Adhikari, Arjun; White, Joseph D

    2014-01-01

    The biogeographic distribution of plant species is inherently associated with the plasticity of physiological adaptations to environmental variation. For semi-arid shrublands with a legacy of saline soils, characterization of soil water-tolerant shrub species is necessary for habitat restoration given future projection of increased drought magnitude and persistence in these ecosystems. Five dominant native shrub species commonly found in the Lower Rio Grande Valley, TX, USA, were studied, namely Acacia farnesiana, Celtis ehrenbergiana, Forestiera angustifolia, Parkinsonia aculeata and Prosopis glandulosa. To simulate drought conditions, we suspended watering of healthy, greenhouse-grown plants for 4 weeks. Effects of soil salinity were also studied by dosing plants with 10% NaCl solution with suspended watering. For soil water deficit treatment, the soil water potential of P. glandulosa was the highest (-1.20 MPa), followed by A. farnesiana (-4.69 MPa), P. aculeata (-5.39 MPa), F. angustifolia (-6.20 MPa) and C. ehrenbergiana (-10.02 MPa). For the soil salinity treatment, P. glandulosa also had the highest soil water potential value (-1.60 MPa), followed by C. ehrenbergiana (-1.70 MPa), A. farnesiana (-1.84 MPa), P. aculeata (-2.04 MPa) and F. angustifolia (-6.99 MPa). Within the species, only C. ehrenbergiana and F. angustifolia for soil water deficit treatment and A. farnesiana for the salinity treatment had significantly lower soil water potential after 4 weeks of treatment (P < 0.05). We found that soil water potential, stomatal conductance and net photosynthesis of the species significantly reduced over time for both treatments (P < 0.05). We conclude that while all species exhibited capacities to withstand current water availability, some species demonstrated limited tolerance for extreme water stress that may be important for management of future shrub diversity in Lower Rio Grande Valley. PMID:27293626

  11. Plant water use characteristics of five dominant shrub species of the Lower Rio Grande Valley, Texas, USA: implications for shrubland restoration and conservation

    PubMed Central

    Adhikari, Arjun; White, Joseph D.

    2014-01-01

    The biogeographic distribution of plant species is inherently associated with the plasticity of physiological adaptations to environmental variation. For semi-arid shrublands with a legacy of saline soils, characterization of soil water-tolerant shrub species is necessary for habitat restoration given future projection of increased drought magnitude and persistence in these ecosystems. Five dominant native shrub species commonly found in the Lower Rio Grande Valley, TX, USA, were studied, namely Acacia farnesiana, Celtis ehrenbergiana, Forestiera angustifolia, Parkinsonia aculeata and Prosopis glandulosa. To simulate drought conditions, we suspended watering of healthy, greenhouse-grown plants for 4 weeks. Effects of soil salinity were also studied by dosing plants with 10% NaCl solution with suspended watering. For soil water deficit treatment, the soil water potential of P. glandulosa was the highest (−1.20 MPa), followed by A. farnesiana (−4.69 MPa), P. aculeata (−5.39 MPa), F. angustifolia (−6.20 MPa) and C. ehrenbergiana (−10.02 MPa). For the soil salinity treatment, P. glandulosa also had the highest soil water potential value (−1.60 MPa), followed by C. ehrenbergiana (−1.70 MPa), A. farnesiana (−1.84 MPa), P. aculeata (−2.04 MPa) and F. angustifolia (−6.99 MPa). Within the species, only C. ehrenbergiana and F. angustifolia for soil water deficit treatment and A. farnesiana for the salinity treatment had significantly lower soil water potential after 4 weeks of treatment (P < 0.05). We found that soil water potential, stomatal conductance and net photosynthesis of the species significantly reduced over time for both treatments (P < 0.05). We conclude that while all species exhibited capacities to withstand current water availability, some species demonstrated limited tolerance for extreme water stress that may be important for management of future shrub diversity in Lower Rio Grande Valley. PMID:27293626

  12. Variability of surface-water quantity and quality and shallow groundwater levels and quality within the Rio Grande Project Area, New Mexico and Texas, 2009–13

    USGS Publications Warehouse

    Driscoll, Jessica M.; Sherson, Lauren R.

    2016-01-01

    Drought conditions during the study period of January 1, 2009, to September 30, 2013, caused a reduction in surface-water releases from water-supply storage infrastructure of the Rio Grande Project, which led to changes in surface-water and groundwater (conjunctive) use in downstream agricultural alluvial valleys. Surface water and groundwater in the agriculturally dominated alluvial Rincon and Mesilla Valleys were investigated in this study to measure the influence of drought and subsequent change in conjunctive water use on quantity and quality of these water resources. In 2013, the U.S. Geological Survey, in cooperation with the New Mexico Environment Department and the New Mexico Interstate Stream Commission, began a study to (1) calculate dissolved-solids loads over the study period at streamgages in the study area where data are available, (2) assess the temporal variability of dissolved-solids loads at and between each streamgage where data are available, and (3) relate the spatiotemporal variability of shallow groundwater data (groundwater levels and quality) within the alluvial valleys of the study area to spatiotemporal variability of surface-water data over the study period. This assessment included the calculation of surface-water dissolved-solids loads at streamgages as well as a mass-balance approach to measure the change in salt load between these streamgages. Bimodal surface-water discharge data led to a temporally-dynamic volumetric definition of release and nonrelease seasons. Continuous surface-water discharge and water-quality data from three streamgages on the Rio Grande were used to calculate daily dissolved-solids loads over the study period, and the results were aggregated annually and seasonally. Results show the majority of dissolved-solids loading occurs during release season; however, decreased duration of the release season over the 5-year study period has resulted in a decrease of the total annual loads at each streamgage

  13. Baseline assessment of instream and riparian-zone biological resources on the Rio Grande in and near Big Bend National Park, Texas

    USGS Publications Warehouse

    Moring, James Bruce

    2002-01-01

    Five study sites, and a sampling reach within each site, were established on the Rio Grande in and near Big Bend National Park in 1999 to provide the National Park Service with data and information on the status of stream habitat, fish communities, and benthic macroinvertebrates. Differences in stream-habitat conditions and riparian vegetation reflect differences in surface geology among the five sampling reaches. In the most upstream reach, Colorado Canyon, where igneous rock predominates, streambed material is larger; and riparian vegetation is less diverse and not as dense as in the four other, mostly limestone reaches. Eighteen species of fish and a total of 474 individuals were collected among the five reaches; 348 of the 474 were minnows. The most fish species (15) were collected at the Santa Elena reach and the fewest species (9) at the Colorado Canyon and Johnson Ranch reaches. The fish community at Colorado Canyon was least like the fish communities at the four other reaches. Fish trophic structure reflected fish-community structure among the five reaches. Invertivores made up at least 60 percent of the trophic structure at all reaches except Colorado Canyon. Piscivores dominated the trophic structure at Colorado Canyon. At the four other reaches, piscivores were the smallest trophic group. Eighty percent of the benthic macroinvertebrate taxa collected were aquatic insects. Two species of blackfly were the most frequently collected invertebrate taxon. Net-spinning caddisflies were common at all reaches except Santa Elena. The aquatic-insect community at the Boquillas reach was least similar to the aquatic-insect community at the other reaches.

  14. Reproductive potential of overwintering, F1, and F2 female boll weevils (Coleoptera: Curculionidae) in the Lower Rio Grande Valley of Texas.

    PubMed

    Greenberg, S M; Sappington, T W; Setamou, M; Armstrong, J S; Coleman, R J; Liu, T-X

    2007-04-01

    The feeding and oviposition activity of overwintering boll weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation boll weevil females were determined in the laboratory at 27 degrees C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female boll weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were approximately 9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation boll weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in boll weevil survival, development, and reproductive potential among

  15. SOLUTION MINING IN SALT DOMES OF THE GULF COAST EMBAYMENT

    SciTech Connect

    Griswold, G. B.

    1981-02-01

    Following a description of salt resources in the salt domes of the gulf coast embayment, mining, particularly solution mining, is described. A scenario is constructed which could lead to release of radioactive waste stored in a salt dome via inadvertent solution mining and the consequences of this scenario are analyzed.

  16. EUTROPHICATION ANALYSIS OF EMBAYMENTS IN PRINCE WILLIAM SOUND, ALASKA

    EPA Science Inventory

    Fertilizers were used in the summer of 1989 to accelerate bacterial growth in a bioremediation effort to clean up the beaches following the EXXON Valdez oil spill. athematical models were used to quantify the eutrophication potential in two selected embayments in Prince William S...

  17. Nearshore sandbar rotation at single-barred embayed beaches

    NASA Astrophysics Data System (ADS)

    Blossier, B.; Bryan, K. R.; Daly, C. J.; Winter, C.

    2016-04-01

    The location of a shore-parallel nearshore sandbar derived from 7 years of video imagery data at the single-barred embayed Tairua Beach (NZ) is investigated to assess the contribution of barline rotation to the overall morphodynamics of sandbars in embayed environments and to characterize the process of rotation in relation to external conditions. Rotation induces cross-shore barline variations at the embayment extremities on the order of magnitude of those induced by alongshore uniform cross-shore migration of the bar. Two semiempirical models have been developed to relate the barline cross-shore migration and rotation to external wave forcing conditions. The rotation model is directly derived from the cross-shore migration model. Therefore, its formulation advocates for a primary role of cross-shore processes in the rotation of sandbars at embayed beaches. The orientation evolves toward an equilibrium angle directly related to the alongshore wave energy gradient due to two different mechanisms. Either the bar extremities migrate in opposite directions with no overall cross-shore bar migration (pivotal rotation) or the rotation relates to an overall migration of the barline which is not uniform along the beach (migration-driven rotation). Migration and rotation characteristic response times are similar, ranging from 10 to 30 days for mild and energetic wave conditions and above 200 days during very calm conditions or when the bar is located far offshore.

  18. Eutrophication analysis of embayments in Prince William Sound, Alaska

    SciTech Connect

    Lung, W.S.; Martin, J.L.; McCutcheon, S.C.

    1993-01-01

    Fertilizers were used in the summer of 1989 to accelerate bacterial growth in a bioremediation effort to clean up the beaches following the EXXON Valdez oil spill. Mathematical models were used to quantify the eutrophication potential in two selected embayments in Prince William Sound: Passage Cove and Snug Harbor. First, mass transport in these two embayments was determined to. Next, eutrophication models were developed for these two embayments to simulate the seasonal algal concentrations prior to fertilizer application. Finally, a series of nutrient-loading-scenarios based on different fertilizer and other chemical application rates were developed to investigate the impact. Model results and the data available indicated that the rapid exchange between embayments and the open water limits algal growth and buildup of concentrations of other chemicals applied to beaches. The exception is the potential for some ammonia toxicity at high application rates. Despite the limited data available it is clear that no significant increased algal growth would be expected following fertilizer application.

  19. Holocene Evolution of Qing'ao Embayment, Southern China

    NASA Astrophysics Data System (ADS)

    Switzer, A. D.; Yu, F.; Chen, B.; Zheng, Z.; Wang, D.

    2012-12-01

    The Holocene evolution of the Qing'ao embayment, Nan'ao Island, southern China, is primarily the result of the interaction of tectonic activity, climate variation and changes in relative sea level. Characterizing the evolutionary history of the relatively small Qing'ao embayment during the Holocene will help improve our understanding of the driving mechanisms of coastal evolution in the area. To reconstruct the Holocene evolution history we analyzed the grain size, loss on ignition (LOI) and carbonate content of modern and core samples. Modern environmental analogs were examined in surface samples ranging from the coastal sand dunes through to offshore. The results of these modern samples suggest that dune sand (mean size of ~2.33Phi) are slightly finer than beach sand (mean size of 2.13Phi), and nearshore sediment is much coarser than offshore sediment (mean size of 5.90Phi). This modern analogs were then applied to 8 percussion cores from the Qing'ao embayment. A chronological framework obtained from 11 radiocarbon samples suggests that the embayment started to accept deposition since early Holocene, ~8500 cal. yr. BP. Three main phases of Holocene evolution were identified. A basin wide shell-rich sand sheet forms the basal Holocene facies and overlies clay rich presumably Pleistocene sediments or bedrock. This facies records an initial sedimentation phase associated with the early Holocene transgression into the embayment (~8500-6000 cal. yr. BP). The basal facies grades upward to a mixed sandy-mud facies which includes lagoonal clayey-silts, flood tide delta sands and records an estuarine phase lasting from ~6000-1000 cal. yr. BP that appears coincident with falling regional sea levels. Coincident with the estuarine phase is a period of coastal dune building recorded as yet undated massive sands that are found in the upper fill. Toward the end of the estuarine phase it is apparent that dune migration has restricted the lagoon entrance and that this was

  20. U. S. Geological Survey investigation of Mississippi Embayment area

    SciTech Connect

    Glick, E.E.

    1983-09-01

    Prior to about 1974, most of the work in the Mississippi embayment area by members of the U.S. Geological Survey was motivated by interest in the embayment's paleontologic aspects, stratigraphy, and economic resources, especially ground water. However, an excellent description of the effects of the New Madrid earthquake series was published on the centennial of that 1811-1812 seismicity. During World War II, combined efforts of the U.S. Geological Survey and the U.S. Bureau of Mines produced a wealth of information about the Little Rock pluton and the process of laterizing exposed nepheline syenite to form bauxite. That project, in a search for additional intrusive bodies at shallow depth, sponsored a reconnaissance aeromagnetic survey along the embayment edge from Little Rock, Arkansas, to Cairo, Illinois. Magnetic anomalies that were identified then are now known to be related to the series of buried plutons aligned along the northwestern margin of the upper Mississippi embayment graben. Later investigations assessed the geochemistry of the more mafic parts of the Little Rock pluton. In 1974, U.S. Geological survey effort, along with that of other federal agencies, state agencies, and academic institutions, was directed toward finding the cause of ongoing seismicity in the upper embayment and toward assessing the related potential effects on persons and property. The purpose of this poster display is to summarize the more significant findings in this area related to (a) the rock sequence, lower crust to surface; (b) the major structural features, including a rift system; (c) the current state of stress; and (d) the present-day seismicity.

  1. Salinity variations and chemical compositions of waters in the Frio Formation, Texas Gulf Coast. Annual report

    SciTech Connect

    Morton, R.A.; Garrett, C.M. Jr.; Posey, J.S.; Han, J.H.; Jirik, L.A.

    1981-11-01

    Waters produced from sandstone reservoirs of the deep Frio Formation exhibit spatial variations in chemical composition that roughly coincide with the major tectonic elements (Houston and Rio Grande Embayments, San Marcos Arch) and corresponding depositional systems (Houston and Norias deltas, Greta-Carancahua barrier/strandplain system) that were respectively active along the upper, lower, and middle Texas Coast during Frio deposition. Within an area, salinities are usually depth dependent, and primary trends closely correspond to pore pressure gradients and thermal gradients. Where data are available (mainly in Brazoria County) the increases in TDS and calcium with depth coincide with the zone of albitization, smectite-illite transition, and calcite decrease in shales. Waters have fairly uniform salinities when produced from the same sandstone reservoir within a fault block or adjacent fault blocks with minor displacement. In contrast, stratigraphically equivalent sandstones separated by faults with large displacement usually yield waters with substantially different salinities owing to the markedly different thermal and pressure gradients across the faults that act as barriers to fluid movement.

  2. Texas Fires

    Atmospheric Science Data Center

    2014-05-15

    article title:  Wind-Whipped Fires in East Texas     View Larger Image ... western side of the storm stoked fires throughout eastern Texas, which was already suffering from the worst one-year drought on record ...

  3. Significant reserve additions from oligocene Hackberry Sands utilizing 3-D seismic, upper Texas and Louisiana Gulf Coast

    SciTech Connect

    Zamboras, R.L.

    1995-10-01

    The Oligocene Hackberry sands of the Hackberry Embayment represent a complex and elusive exploration target. 3-D seismic evaluation along the headward erosional limits of the embayment provides a reconstructive framework of tectonic and sedimentation patterns which facilitate hydrocarbon exploration. The 3-D seismic along the Orange County, Texas portion of the Oligocene Hackberry trend indicates: (1) similarities of Hackberry structural and depositional setting to that of the underlying Eocene Yegua Formation; (2) four distinct cyclical sedimentation episodes associated with basin floor slump faulting: (3) the usefulness of seismic attributes as direct hydrocarbon indicators, and (4) the potential for significant oil and gas reserves additions in a mature trend. The Hackberry embayment represents a microcosm of the basin structural and depositional processes. Utilizing 3-D seismic to lower risk and finding cost will renew interest in trends such as the Hackberry of the Upper Texas-Louisiana Gulf Coast.

  4. Floodplain and wetlands assessment of the White Oak Creek Embayment

    SciTech Connect

    Not Available

    1991-07-01

    This report describes the proposed methods for dealing with contaminants that have accumulated in White Oak Creek, White Oak Lake, and the White Oak Creek Embayment as a result of process releases and discharges from the Oak Ridge National Laboratory. Alternative methods of cleaning up the area which were considered in accordance with regulatory guidelines are listed, and information supporting the selected methods is provided. Also included are results of a site survey conducted at the White Oak Creek Embayment and the expected effects of the proposed control structures on the floodplain and wetlands. The appendix contains figures showing the nine cross-sections of the stream channel surveyed during studies of the White Oak Creek area.

  5. Tectonic history of Mississippi embayment and surrounding areas

    SciTech Connect

    Viele, G.W.; Thomas, W.A.

    1983-09-01

    Recently published U.S. Geological Survey gravity and magentic maps constitute powerful tools for interpreting the tectonic nature and history of the northern part of the Mississippi embayment. Perhaps the most striking feature of the maps is a set of alternating, roughly coincident gravity and magnetic anomalies that bear northeastward and extend from the northwestern edge of the embayment to Alabama. Positive anomalies in this set are viewed, using the model of McKensie, as zones of streching, thinning, and subsidence of the continental lithosphere. Gradients between positive and negative anomalies may mark the position of listric faults, which blocked out grabens and horsts within the basement rocks, forming a low-relief crustal mosaic. This mosaic was jostled by the Ouachita collision during the Late Pennsylvanian. A horst on the northwestern flank of the embayment was pushed slightly northeastward and uplifted at its northeastern end to form the Pascola arch. Potential field maps provide no evidence that the Pascola arch connected the Ozark and Nashville domes. Older structures athwart the region trend of the mosaic, such as the Ste. Genevieve and Rough Creek faults, were reactivated as thrust faults up on their southern sides. In the Early Permian, alkalic dikes were intruded in the region of the Illinois Mineral District providing the earliest evidence of a lens of low velocity mantle rock beneath the embayment. Radiometric dates suggest alkalic igneous activity peaked in the Cretaceous. In this scenario, the Reelfoot region evolved from a broad complex graben to a true rift during the late Paleozoic. Mesozoic igneous events and present seismicity suggest that the Reelfoot is not a dying rift; it is instead being born.

  6. Seismotectonic implications of sand blows in the southern Mississippi Embayment

    USGS Publications Warehouse

    Cox, R.T.; Hill, A.A.; Larsen, D.; Holzer, T.; Forman, S.L.; Noce, T.; Gardner, C.; Morat, J.

    2007-01-01

    We explore seismically-induced sand blows from the southern Mississippi Embayment and their implications in resolving the question of near or distal epicentral source region. This was accomplished using aerial photography, field excavations, and cone penetration tests. Our analysis shows that three sand blow fields exhibit a distinct chronology of strong ground motion for the southern embayment: (1) The Ashley County, Arkansas sand blow field, near the Arkansas/Louisiana state border, experienced four Holocene sand venting episodes; (2) to the north, the Desha County field experienced at least three episodes of liquefaction; and (3) the Lincoln-Jefferson Counties field experienced at least one episode. Cone penetration tests (CPT) conducted in and between the sand blow fields suggest that the fields may not be distal liquefaction associated with New Madrid seismic zone earthquakes but rather are likely associated with strong earthquakes on local faults. This conclusion is consistent with the differences in timing of the southern embayment sand venting episodes and those in the New Madrid seismic zone. These results suggest that active tectonism and strong seismicity in intraplate North America may not be localized at isolated weak spots, but rather widespread on fault systems that are favorably oriented for slip in the contemporary stress field. ?? 2006 Elsevier B.V. All rights reserved.

  7. Two-dimensional water quality modeling of Town Creek embayment on Guntersville Reservoir

    SciTech Connect

    Bender, M.D.; Shiao, Ming C.; Hauser, G.E. . Engineering Lab.); Butkus, S.R. . Water Quality Dept.)

    1990-09-01

    TVA investigated water quality of Town Creek embayment using a branched two-dimensional model of Guntersville Reservoir. Simulation results were compared in terms of algal biomass, nutrient concentrations, and volume of embayment with depleted dissolved oxygen. Stratification and flushing play a significant role in the embayment water quality. Storms introduce large loadings of organics, nutrients, and suspended solids. Dissolved oxygen depletion is most severe after storms followed by low flow that fails to flush the embayment. Embayment water quality responses to potential animal waste and erosion controls were explored. Modeling indicated animal waste controls were much more cost-effective than erosion controls. Erosion controls will decrease embayment suspended solids and thereby increase algal biomass due to greater light penetration. 29 refs., 16 figs., 4 tabs.

  8. Substance Abuse in the Rio Grande Valley.

    ERIC Educational Resources Information Center

    Zavaleta, Anthony N.

    1979-01-01

    In the Mexican American barrios of Texas' Lower Rio Grande Valley, existence is complicated by the interactive forces of culture, society, and economy. These three factors act in unison to create an etiology of alcohol and drug use and abuse which is poorly understood by persons outside the barrio's grasp. (Author/NQ)

  9. Nutrient budgets for large Chinese estuaries and embayment

    NASA Astrophysics Data System (ADS)

    Liu, S. M.; Hong, G.-H.; Ye, X. W.; Zhang, J.; Jiang, X. L.

    2009-01-01

    Nutrient concentrations among the Chinese rivers and bays vary 10-75 fold depending on nutrient elements. The silicic acid levels in South China rivers are higher than those from North China rivers and the yields of dissolved silicate increased from the north to the south of China, indicating the effect of climate on weathering. The nutrient levels in Chinese rivers are higher than those from the large and less-disturbed world rivers such as Amazon and Zaire, but comparable to the values for European and North American polluted and eutrophic rivers like the Loire and Po. This may be ascribed to both of extensive leaching and influences from agricultural and domestic activities over the drainage basins of Chinese rivers. DIN:PO3-4 ratios in most of Chinese rivers and bays are higher (up to 2800) than the other rivers in the world. The atomic ratios of DIN to PO43- in the major Chinese rivers and embayment decrease in exponential trend with increase in the atomic ratios of PO43- to Si(OH)4, indicating that primary production in coastal environments changes with the nutrients transport when the urbanization develops to a certain extent, and the potential limited nutrient elements can be changed from phosphorus to nitrogen limitation, which can modify aquatic food webs and then the ocean ecosystem. A simple steady-state mass-balance box model was employed. The output shows that the estuaries and embayment behave as a sink or source of nutrients. For the major Chinese estuaries, both residual and mixing flow transport nutrients off the estuaries, and nutrient transport fluxes in summer is 3-4 fold that in winter except comparable for NH4+. These fluxes are 1.0-1.7 fold that estimated by timing riverine nutrient concentrations and freshwater discharge. For the major Chinese embayment, nutrient elements are transported to China Seas except PO43- and Si(OH)4 in Sanggou Bay and Jiaozhou Bay. Seasonally, nutrients transport fluxes off the bays in the summer are 2.2-7.0 fold

  10. Upper Mississippi embayment shallow seismic velocities measured in situ

    USGS Publications Warehouse

    Liu, Huaibao P.; Hu, Y.; Dorman, J.; Chang, T.-S.; Chiu, J.-M.

    1997-01-01

    Vertical seismic compressional- and shear-wave (P- and S-wave) profiles were collected from three shallow boreholes in sediment of the upper Mississippi embayment. The site of the 60-m hole at Shelby Forest, Tennessee, is on bluffs forming the eastern edge of the Mississippi alluvial plain. The bluffs are composed of Pleistocene loess, Pliocene-Pleistocene alluvial clay and sand deposits, and Tertiary deltaic-marine sediment. The 36-m hole at Marked Tree, Arkansas, and the 27-m hole at Risco, Missouri, are in Holocene Mississippi river floodplain sand, silt, and gravel deposits. At each site, impulsive P- and S-waves were generated by man-made sources at the surface while a three-component geophone was locked downhole at 0.91-m intervals. Consistent with their very similar geology, the two floodplain locations have nearly identical S-wave velocity (VS) profiles. The lowest VS values are about 130 m s-1, and the highest values are about 300 m s-1 at these sites. The shear-wave velocity profile at Shelby Forest is very similar within the Pleistocene loess (12m thick); in deeper, older material, VS exceeds 400 m s-1. At Marked Tree, and at Risco, the compressional-wave velocity (VP) values above the water table are as low as about 230 m s-1, and rise to about 1.9 km s-1 below the water table. At Shelby Forest, VP values in the unsaturated loess are as low as 302 m s-1. VP values below the water table are about 1.8 km s-1. For the two floodplain sites, the VP/VS ratio increases rapidly across the water table depth. For the Shelby Forest site, the largest increase in the VP/VS ratio occurs at ???20-m depth, the boundary between the Pliocene-Pleistocene clay and sand deposits and the Eocene shallow-marine clay and silt deposits. Until recently, seismic velocity data for the embayment basin came from earthquake studies, crustal-scale seismic refraction and reflection profiles, sonic logs, and from analysis of dispersed earthquake surface waves. Since 1991, seismic data

  11. Statistical study of ground motion amplification in the Mississippi embayment

    NASA Astrophysics Data System (ADS)

    Malekmohammadi, Mojtaba

    Three important topics have been studied in this dissertation. First, the effects of deep soil deposits of the Mississippi embayment in ground motion amplification have been studied. Using the results of one-dimensional analyses, a parametric model is developed for the region to estimate the ground motion amplification. The averaged shear-wave velocity in the upper 30 meter, Vs30, ranging from 220 to 800 m/s and deposit thickness varying from 70 to 750m, are considered in the estimation of the ground motion amplification with respect to a generic bedrock profile of the Mississippi embayment. Results indicate that site factors suggested by seismic codes cannot capture the site properties of the Mississippi embayment and are not appropriate for the region. In the second part, a new step-by-step method is developed to select a set of ground motions which takes into account a site-specific Probabilistic Seismic Hazard Analysis (PSHA) and the associated uncertainties through the defined logic tree. In the proposed method, after capturing the variability of the Uniform Hazard Response Spectrum (UHRS), I used a Monte Carlo procedure to produce a set of response spectra that has mean equals to the target and variability close to the variability of the target at all the spectral periods. Each member of the generated set is called individual target response spectra, and ground motions from the database of real data and also synthetic ground motions are selected based on their similarity with the individual target response spectra. The method's procedure is defined through studying a sample site in North of the Mississippi embayment. In the last part of the study I developed a model for the ratio of Vertical to Horizontal component of earthquakes (V/H ratio) for the Mississippi embayment. This model can be used in developing the site-specific vertical design spectrum for the region by scaling the horizontal design spectrum resulting from a PSHA. The input parameters of the

  12. Structural history of Southern Illinois and Upper Mississippi Embayment

    SciTech Connect

    Schwalb, H.R.

    1983-09-01

    Early crustal failure produced deep grabens which filled with fluvial and marine sediments. Subsequent growth faulting during the Paleozoic deepened these troughs, allowing deposition of thick sedimentary sequences in the Reelfoot basin and Rough Creek graben. Uplift of the Pascola arch closed the Illinois basin to the south, and erosion along the arch removed much of the sedimentary record. Subsidence of the Mississippi embayment area allowed deposition of southward thickening continental and marine sediments. Subsequent erosion has produced the present-day areal distribution of geologic units.

  13. A Model for Health Professional Education in South Texas

    ERIC Educational Resources Information Center

    Ramirez, Amelie; Vela, Leonel; Cigarroa, Francisco G.

    2008-01-01

    In 1997, The University of Texas Health Science Center at San Antonio established the Regional Academic Health Center (RAHC) for the Lower Rio Grande Valley in south Texas. Through medical education programs, research facilities, and partnerships with health-care providers, the RAHC aims to improve the health status and access to health services…

  14. Productive lower Wilcox distributary channel sands of Hallettsville embayment, Lavaca County, Texas

    SciTech Connect

    Chuber, S.; Howell, H.H.

    1986-09-01

    Whole-core petrographic and micropaleontological analyses from four wells and subsurface studies in three new fields of the Hallettsville area define a heretofore unsuspected deltaic suite of facies in the lower Wilcox. Massive distributary channel sands up to 250 ft thick are interbedded with overbank silts and shales as well as marsh, crevasse-splay, and natural levee sediments. Sparse microfauna indicate a restricted marine, shallow neritic, or nonmarine facies with reworked Cretaceous forms. Three channels have been productive to date: the Renger and Golsch (gas bearing) and the Hathaway (oil bearing). Even with dipmeter, whole-core, and abundant seismic data available, the narrow, sinuous channel sands are difficult to locate. Once penetrated, however, the sands produce either oil or condensate-rich gas in copious amounts.

  15. Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

    USGS Publications Warehouse

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.; Byappanahalli, Muruleedhara N.

    2012-01-01

    Numerical simulations of the transport and fate of Escherichia coli were conducted at Chicago's 63rd Street Beach, an embayed beach that had the highest mean E. coli concentration among 23 similar Lake Michigan beaches during summer months of 2000-2005, in order to find the cause for the high bacterial contamination. The numerical model was based on the transport of E. coli by current circulation patterns in the embayment driven by longshore main currents and the loss of E. coli in the water column, taking settling as well as bacterial dark- and solar-related decay into account. Two E. coli loading scenarios were considered: one from the open boundary north of the embayment and the other from the shallow water near the beachfront. Simulations showed that the embayed beach behaves as a sink for E. coli in that it generally receives E. coli more efficiently than it releases them. This is a result of the significantly different hydrodynamic forcing factors between the inside of the embayment and the main coastal flow outside. The settled E. coli inside the embayment can be a potential source of contamination during subsequent sediment resuspension events, suggesting that deposition-resuspension cycles of E. coli have resulted in excessive bacterial contamination of beach water. A further hypothetical case with a breakwater shortened to half its original length, which was anticipated to enhance the current circulation in the embayment, showed a reduction in E. coli concentrations of nearly 20%.

  16. Nearshore hydrodynamics as loading and forcing factors for Escherichia coli contamination at an embayed beach

    USGS Publications Warehouse

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.; Byappanahalli, Muruleedhara N.

    2012-01-01

    Numerical simulations of the transport and fate of Escherichia coli were conducted at Chicago’s 63rd Street Beach, an embayed beach that had the highest mean E. coli concentration among 23 similar Lake Michigan beaches during summer months of 2000-2005, in order to find the cause for the high bacterial contamination. The numerical model was based on the transport of E. coli by current circulation patterns in the embayment driven by longshore main currents and the loss of E. coli in the water column, taking settling as well as bacterial dark- and solar-related decay into account. Two E. coli loading scenarios were considered: one from the open boundary north of the embayment and the other from the shallow water near the beachfront. Simulations showed that the embayed beach behaves as a sink for E. coli in that it generally receives E. coli more efficiently than it releases them. This is a result of the significantly different hydrodynamic forcing factors between the inside of the embayment and the main coastal flow outside. The settled E. coli inside the embayment can be a potential source of contamination during subsequent sediment resuspension events, suggesting that deposition-resuspension cycles of E. coli have resulted in excessive bacterial contamination of beach water. A further hypothetical case with a breakwater shortened to half its original length, which was anticipated to enhance the current circulation in the embayment, showed a reduction in E. coli concentrations of nearly 20%.

  17. Coliform contamination of a coastal embayment: Sources and transport pathways

    USGS Publications Warehouse

    Weiskel, P.K.; Howes, B.L.; Heufelder, G.R.

    1996-01-01

    Fecal bacterial contamination of nearshore waters has direct economic impacts to coastal communities through the loss of shellfisheries and restrictions of recreational uses. We conducted seasonal measurements of fecal coliform (FC) sources and transport pathways contributing to FC contamination of Buttermilk Bay, a shallow embayment adjacent to Buzzards Bay, MA. Typical of most coastal embayments, there were no direct sewage discharges (i.e., outfalls), and fecal bacteria from human, domestic animal, and wildlife pools entered open waters primarily through direct deposition or after transport through surface waters or groundwaters. Direct fecal coliform inputs to bay waters occurred primarily in winter (December-March) from waterfowl, ~33 x 1012 FC yr-1 or ~67% of the total annual loading. Effects of waterfowl inputs on bay FC densities were mitigated by their seasonality, wide distribution across the bay surface, and the apparent limited dispersal from fecal pellets. On-site disposal of sewage by septic systems was the single largest FC source in the watershed-embayment system, 460 x 1012 FC yr-1, but due to attenuation during subsurface transport only a minute fraction, < 0.006 x 1012 FC yr-1, reached bay waters (<0.01% of annual input to bay). Instead, surface water flows, via storm drains and natural streams under both wet- and dry-weather conditions, contributed the major terrestrial input, 12 x 1012 FC yr-1 (24% of annual input), all from animal sources. Since most of the surface water FC inputs were associated with periodic, short-duration rain events with discharge concentrated in nearshore zones, wet-weather flows were found to have a disproportionately high impact on nearshore FC levels. Elution of FC from shoreline deposits of decaying vegetation (wrack) comprised an additional coliform source. Both laboratory and field experiments suggest significant elution of bacteria from wrack, ~3 x 1012 FC yr-1 on a bay-wide basis (6% of annual input), primarily

  18. Water quality monitoring report for the White Oak Creek Embayment

    SciTech Connect

    Ford, C.J. ); Wefer, M.T. )

    1993-01-01

    Water quality monitoring activities that focused on the detection of resuspended sediments in the Clinch River were conducted in conjunction with the White Oak Creek Embayment (WOCE) time-critical Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to construct a sediment-retention structure at the mouth of White Oak Creek (WOC). Samples were collected by use of a 24-h composite sampler and through real-time water grab sampling of sediment plumes generated by the construction activities. Sampling stations were established both at the WOC mouth, immediately adjacent to the construction site, and at K-1513, the Oak Ridge K-25 Site drinking water intake approximately 9.6 km downstream in the Clinch River. Results are described.

  19. Loss of native rocky reef biodiversity in Australian metropolitan embayments.

    PubMed

    Stuart-Smith, Rick D; Edgar, Graham J; Stuart-Smith, Jemina F; Barrett, Neville S; Fowles, Amelia E; Hill, Nicole A; Cooper, Antonia T; Myers, Andrew P; Oh, Elizabeth S; Pocklington, Jacqui B; Thomson, Russell J

    2015-06-15

    Urbanisation of the coastal zone represents a key threat to marine biodiversity, including rocky reef communities which often possess disproportionate ecological, recreational and commercial importance. The nature and magnitude of local urban impacts on reef biodiversity near three Australian capital cities were quantified using visual census methods. The most impacted reefs in urbanised embayments were consistently characterised by smaller, faster growing species, reduced fish biomass and richness, and reduced mobile invertebrate abundance and richness. Reef faunal distribution varied significantly with heavy metals, local population density, and proximity to city ports, while native fish and invertebrate communities were most depauperate in locations where invasive species were abundant. Our study adds impetus for improved urban planning and pollution management practises, while also highlighting the potential for skilled volunteers to improve the tracking of changes in marine biodiversity values and the effectiveness of management intervention. PMID:25882229

  20. Sedimentation processes in a coral reef embayment: Hanalei Bay, Kauai

    USGS Publications Warehouse

    Storlazzi, C.D.; Field, M.E.; Bothner, Michael H.; Presto, M.K.; Draut, A.E.

    2009-01-01

    Oceanographic measurements and sediment samples were collected during the summer of 2006 as part of a multi-year study of coastal circulation and the fate of terrigenous sediment on coral reefs in Hanalei Bay, Kauai. The goal of this study was to better understand sediment dynamics in a coral reef-lined embayment where winds, ocean surface waves, and river floods are important processes. During a summer period that was marked by two wave events and one river flood, we documented significant differences in sediment trap collection rates and the composition, grain size, and magnitude of sediment transported in the bay. Sediment trap collection rates were well correlated with combined wave-current near-bed shear stresses during the non-flood periods but were not correlated during the flood. The flood's delivery of fine-grained sediment to the bay initially caused high turbidity and sediment collection rates off the river mouth but the plume dispersed relatively quickly. Over the next month, the flood deposit was reworked by mild waves and currents and the fine-grained terrestrial sediment was advected around the bay and collected in sediment traps away from the river mouth, long after the turbid surface plume was gone. The reworked flood deposits, due to their longer duration of influence and proximity to the seabed, appear to pose a greater long-term impact to benthic coral reef communities than the flood plumes themselves. The results presented here display how spatial and temporal differences in hydrodynamic processes, which result from variations in reef morphology and orientation, cause substantial variations in the deposition, residence time, resuspension, and advection of both reef-derived and fluvial sediment over relatively short spatial scales in a coral reef embayment.

  1. Mathematical modeling of stormwater pollution in a tidal embayment

    SciTech Connect

    Najjar, K.F.

    1989-01-01

    It has been recognized for many years that stormwater runoff provides a transport mechanism for non-point pollutants into the nation's waterways. As more watershed areas continue to urbanize, greater increases in pollutant loadings will continue to impact the water quality of the receiving water bodies. In many instances, the pollutant impact exceeds the assimilative capacity of the receiving water. To estimate the potential impacts of stormwater pollution, mathematical models are constructed. In this dissertation, mathematical models have been constructed to estimate the non-point pollutant loadings from an urbanizing area as well as to model the assimilative capacity of the receiving tidal embayment system. The models are capable of simulating the hydrologic aspects as well as the water quality cycles of the system as a function of urbanization. In determining the response of the receiving water system to stormwater loadings, the change in receiving water quality is modeled spatially as well as temporally. The overall model is composed of three subsystem models: a stormwater model, a hydrodynamic tidal model, and a receiving water quality model. Construction of the stormwater model is based on STORM (Storage, Treatment, Overflow, Runoff Model) by the US Army Corps of Engineers. A ground water component to the model has been added to adjust the model for application to the study area, Lakes Bay, New Jersey. The tidal model is developed from a pseudo two-dimensional approach. The methodology utilizes the link-node concept to simulate the embayment system. Solutions to equations of motion and continuity are solved using a finite difference method. The receiving water quality model is a two-dimensional time variable water quality model which is based in a finite segment approach.

  2. The responses of artificial embayed beaches to storm events

    NASA Astrophysics Data System (ADS)

    Ojeda, E.; Guillén, J.; Ribas, F.

    2009-09-01

    The plan-view and the profile shape of sandy beaches largely depend on the incoming wave-energy (Wright and Short, 1984). In this sense, storm events are responsible for major changes in the configuration of sandy beaches and the cumulative effect of storms and fair-weather conditions determines the morphodynamic state of a certain beach. With increasing wave energy, the beach will change from the Reflective state to the Low Tide Terrace, Transverse Bar and Rip, Rhythmic Bar and Beach, Longshore Bar and Trough and finally to the Dissipative beach state. These morphodynamic states are also observed at artificial embayed beaches, although artificial groins limit alongshore sediment transport and protect sections of the beach from waves approaching from a range of directions (Short and Masselink, 1999). This contribution focuses on the morphological changes of the shoreline and the submerged sandbars of artificial embayed (sandy) beaches due to the effect of high-wave conditions associated to storms. We characterize the morphological response of the emerged and submerged beach profile of two of the artificial embayed beaches of the Barcelona city coast (NW Mediterranean). The two embayed beaches under study are single-barred beaches subject to the same climatic conditions but with different morphological characteristics. The study comprises more than 4 years of data, from November 2001 to March 2006, obtained through an Argus video system (Holman and Stanley, 2007). The extraction of the shoreline and barline locations is accomplished using 10-minute time-exposure video images. Shorelines were extracted directly from oblique images (see Ojeda and Guillén, [2008] for a complete description) and rectified afterwards. Sandbars were inferred from the rectified time-exposure video images based on the preferential wave breaking over shallow areas, so they required a minimum significant wave height (Hs) which allowed the occurrence of a clear wave-breaking pattern. The

  3. PECONIC ESTUARY: AN ASSESSMENT OF SHELLFISH RESOURCES IN THE TRIBUTARIES AND EMBAYMENTS OF THE PECONIC ESTUARY

    EPA Science Inventory

    Executive Summary Historically, the Peconic Estuary's shellfish resources have supported significant fisheries for a number of species including hard clams, oysters and bay scallops. However, distribution and abundance data for the tributaries and embayments within the Peconic Es...

  4. Equilibrium bed profiles in an idealized two-inlet embayment

    NASA Astrophysics Data System (ADS)

    Salles, Paulo; Meerman, Corine; Schuttelaars, Henk

    2015-04-01

    Multiple inlet systems are present at many coasts worldwide, often in coastal areas with high ecological and/or economical value (e.g., Wadden Sea, Venice Lagoon, Terminos Lagoon, etc). These coastal systems are highly dynamic, and their equilibrium is fragile. The stability depends mainly on the sediment dynamics at the inlet and inside the embayment, as well as numerous other factors and processes, such as inlet and embayment geometries, sediment properties, sediment availability, tidal and wave forcing, wind, fresh water input, and human interventions. It also depends on the presence of watersheds inside the system that can generate subembayments during some periods of the tidal cycle or longer timescales (e.g., dry season), and consequently modify the residual circulation and transport, which in turn can affect the long-term stability. This study focuses particularly on the equilibrium bed profile in a two-inlet system, as a function of varying conditions (inlet depth, basin length, tidal amplitude and nonlinearity). In order to address this, an idealized cross-sectionally averaged semi-analytical model was developed, in which only the essential physical processes are taken into account. The basin is assumed to be short (compared to the wavelength) and shallow, and the width may vary in the along-channel direction. The water motion is described by the depth averaged shallow water equations. The model is forced at each inlet with a mean surface elevation, a prescribed semidiurnal signal (M2) and its first overtide (M4), and the depths at the entrances are prescribed. The sediment transport is described by a depth integrated advection-diffusion equation, and the bed evolves due to the divergence of tidally-averaged bedload and suspended load fluxes. Model results of equilibrium bottom profiles suggest that morphodynamic equilibria can be found in such two-inlet systems. The observed equilibrium profiles show the formation of watersheds, with its location and

  5. Detrital zircon study of the Dezful Embayment in the central Zagros, southern Iran

    NASA Astrophysics Data System (ADS)

    Hsieh, Hao Cheng; Chung, Sun Lin; Talebian, Morteza; Chen, Ling; Zarrinkoub, Mohammad H.; Lee, Hao Yang

    2016-04-01

    The Dezful Embayment of the Zagros Simply Folded Belt (ZFTB) in southern Iran is a foreland basin that formed as a flexural basin during the Miocene by the Zagros orogeny. This study reports a LA-ICPMS analysis of zircon U-Pb geochronology of 13 sedimentary rock samples from the Dezful Embayment, and five others from the Urumieh-Dokhtar magmatic arc (UDMA) and the Sanandaj-Sirjan zone (SSZ). In the northern and central parts of the Dezful Embayment, samples were collected from four principal sedimentary sequences including, from bottom to top, the Gachsaran Formation, Mishan Formation, Agha Jari Formation and Bakhtyari Formation. Our new zircon ages, together with published geochronological data from the UDMA and SSZ, can be used to better constrain the source provenance and tectonic implication of the Dezful Embayment related to the Arabia-Eurasia collision following the closure of Neo-Tethys. Samples of the UDMA and SSZ are characterized by abundant zircon ages of Eocene to Oligocene (55-25 Ma) and Jurassic (176-144 Ma), respectively. In the Dezful Embayment, detrital zircon age populations show significant variations. The age spectra of the northern Embayment show major peaks at the Precambrian (950-550 Ma), Late Carboniferous (323-299 Ma), Jurassic (176-144 Ma) and Eocene to Oligocene (55-25 Ma), with the last two age peaks suggesting an important source provenance from Eurasia, involving the SSZ and UDMA. By contrast, in the central Embayment, detrital zircons are dominated by Precambrian ages (2500 Ma, 1850 Ma, and 950-550 Ma), with rare Jurassic and Cenozoic ages. This suggests a different sedimentary source that we interpret to be the Arabian continent from the south. Moreover, gradual changes in the detrital zircon age spectra and thus in the source provenances are observed in different parts of the Dezful Embayment. The change in the northern Embayment occurred in the Agha Jari Formation, earlier than that in the central Embayment occurring between the

  6. White Oak Creek Embayment site characterization and contaminant screening analysis

    SciTech Connect

    Blaylock, B.G.; Ford, C.J.; Frank, M.L.; Hoffman, F.O.; Hook, L.A.

    1993-01-01

    Analyses of sediment samples collected near the mouth of White Oak Creek during the summer of 1990 revealed [sup 137]Cs concentrations [> 10[sup 6] Bq/kg dry wt (> 10[sup 4] pCi/g dry wt)] near the sediment surface. Available evidence indicates that these relatively high concentrations of [sup 137]Cs now at the sediment surface were released from White Oak Dam in the mid-1950s and had accumulated at depositionalsites in the embayment. These accumulated sediments are being eroded and transported downstream primarily during winter low-water levels by flood events and by a combination of normal downstream flow and the water turbulence created by the release of water from Melton Hill Dam during hydropower generation cycles. This report provides a more thorough characterization of the extent of contamination in WOCE than was previously available. Environmental samples collected from WOCE were analyzed for organic, inorganic, and radiological contaminants in fish, water, and sediment. These results were used to conduct a human health effects screening analysis. Walkover radiation surveys conducted inside the fenced area surrounding the WOCE at summer-pool (741 ft MSL) and at winter-pool (733 ft MSL) level, indicated a maximum exposure rate of 3 mR h[sup 1] 1 m above the soil surface.

  7. An oceanic heat transport pathway to the Amundsen Sea Embayment

    NASA Astrophysics Data System (ADS)

    Rodriguez, Angelica R.; Mazloff, Matthew R.; Gille, Sarah T.

    2016-05-01

    The Amundsen Sea Embayment (ASE) on the West Antarctic coastline has been identified as a region of accelerated glacial melting. A Southern Ocean State Estimate (SOSE) is analyzed over the 2005-2010 time period in the Amundsen Sea region. The SOSE oceanic heat budget reveals that the contribution of parameterized small-scale mixing to the heat content of the ASE waters is small compared to advection and local air-sea heat flux, both of which contribute significantly to the heat content of the ASE waters. Above the permanent pycnocline, the local air-sea flux dominates the heat budget and is controlled by seasonal changes in sea ice coverage. Overall, between 2005 and 2010, the model shows a net heating in the surface above the pycnocline within the ASE. Sea water below the permanent pycnocline is isolated from the influence of air-sea heat fluxes, and thus, the divergence of heat advection is the major contributor to increased oceanic heat content of these waters. Oceanic transport of mass and heat into the ASE is dominated by the cross-shelf input and is primarily geostrophic below the permanent pycnocline. Diagnosis of the time-mean SOSE vorticity budget along the continental shelf slope indicates that the cross-shelf transport is sustained by vorticity input from the localized wind-stress curl over the shelf break.

  8. SNOW: THE REAL WATER SUPPLY FOR THE RIO GRANDE BASIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rio Grande basin in Colorado, New Mexico, Texas, and Mexico is an important drainage in southwestern North America, vital for water consumption by a rapidly growing population, irrigated agriculture, economic development, preservation of endangered species, and energy generation. The most impor...

  9. ASSESSING TRANSBOUNDARY INFLUENCES IN THE LOWER RIO GRANDE VALLEY

    EPA Science Inventory

    The Lower Rio Grande Valley Transboundary Air Pollution Project (TAPP) was a U.S.-Mexico Border XXI Program project to assess transboundary air pollution in and near Brownsville, Texas. The study used a three-site air monitoring network very close to the border to capture the d...

  10. 46 CFR 7.105 - Marquesas Keys, FL to Rio Grande, TX.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the seaward limits of the territorial sea (as defined in 33 CFR 2.22(a)(1)) to Rio Grande, Texas at... 46 Shipping 1 2012-10-01 2012-10-01 false Marquesas Keys, FL to Rio Grande, TX. 7.105 Section 7... LINES Gulf Coast § 7.105 Marquesas Keys, FL to Rio Grande, TX. A line drawn from Marquesas Keys,...

  11. 46 CFR 7.105 - Marquesas Keys, FL to Rio Grande, TX.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the seaward limits of the territorial sea (as defined in 33 CFR 2.22(a)(1)) to Rio Grande, Texas at... 46 Shipping 1 2014-10-01 2014-10-01 false Marquesas Keys, FL to Rio Grande, TX. 7.105 Section 7... LINES Gulf Coast § 7.105 Marquesas Keys, FL to Rio Grande, TX. A line drawn from Marquesas Keys,...

  12. 46 CFR 7.105 - Marquesas Keys, FL to Rio Grande, TX.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the seaward limits of the territorial sea (as defined in 33 CFR 2.22(a)(1)) to Rio Grande, Texas at... 46 Shipping 1 2010-10-01 2010-10-01 false Marquesas Keys, FL to Rio Grande, TX. 7.105 Section 7... LINES Gulf Coast § 7.105 Marquesas Keys, FL to Rio Grande, TX. A line drawn from Marquesas Keys,...

  13. 46 CFR 7.105 - Marquesas Keys, FL to Rio Grande, TX.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the seaward limits of the territorial sea (as defined in 33 CFR 2.22(a)(1)) to Rio Grande, Texas at... 46 Shipping 1 2011-10-01 2011-10-01 false Marquesas Keys, FL to Rio Grande, TX. 7.105 Section 7... LINES Gulf Coast § 7.105 Marquesas Keys, FL to Rio Grande, TX. A line drawn from Marquesas Keys,...

  14. 46 CFR 7.105 - Marquesas Keys, FL to Rio Grande, TX.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the seaward limits of the territorial sea (as defined in 33 CFR 2.22(a)(1)) to Rio Grande, Texas at... 46 Shipping 1 2013-10-01 2013-10-01 false Marquesas Keys, FL to Rio Grande, TX. 7.105 Section 7... LINES Gulf Coast § 7.105 Marquesas Keys, FL to Rio Grande, TX. A line drawn from Marquesas Keys,...

  15. DRAFT LANDSAT DATA MOSAIC: MONTGOMERY COUNTY, TEXAS; HARRIS COUNTY, TEXAS; FORT BEND COUNTY, TEXAS; BRAZORIA COUNTY, TEXAS; GALVESTON COUNTY, TEXAS

    EPA Science Inventory

    This is a draft Landsat Data Mosaic, which contains remote sensing information for Montgomery County, Texas Harris County, Texas Fort Bend County, Texas Brazoria County, Texas Galveston County, and Texas Imagery dates on the following dates: October 6, 1999 and September 29, 200...

  16. The dynamics of cooling water discharge in a shallow, non-tidal embayment

    NASA Astrophysics Data System (ADS)

    Hofmeister, Richard; Bolding, Karsten; Hetland, Robert D.; Schernewski, Gerald; Siegel, Herbert; Burchard, Hans

    2013-12-01

    The dynamics of cooling water spreading in a non-tidal embayment is subject of a modelling-based study of Greifswald Bay, a shallow embayment at the south-western coast of the Baltic Sea. Potential cooling water spreading due to a possible power plant at Greifswald Bay is evaluated as differences between a realistic hind-cast simulation and a similar simulation but including the cooling water pumping. The model results are confirmed with satellite imagery of the embayment during operation of a nuclear power plant in the 1980s. The effect of cooling water pumping on the residual circulation, additional stratification and the heating of near-bed waters in the herring spawning areas is evaluated from the simulation. The model results for an idealised embayment and the realistic scenario, as well as the satellite images, show a clear dependence of the plume spreading on the wind direction. Although the surface plume affects a large area of the embayment, the results show a localised impact on residual circulation, bulk stratification and heating of the waterbody.

  17. Distribution, abundance and bionomics of Aedes albopictus in southern Texas.

    PubMed

    Womack, M L

    1993-09-01

    A survey was conducted for Aedes albopictus in southern Texas during the summer of 1992. Thirty-five new country records were added to the distribution of this imported mosquito in Texas. Aedes albopictus was widely distributed throughout the ecological regions in the survey area, but its abundance decreased in counties adjacent to the Rio Grande River. However, these counties had high densities of Aedes aegypti. PMID:8245952

  18. Late Quaternary depositional history of the Albemarle Embayment, NC

    SciTech Connect

    Riggs, S.R.; Klingman, C.R.; Wyrick, R.A. . Dept. of Geology)

    1993-03-01

    The depositional history of Albemarle Embayment documents deep fluvial incisement by the Roanoke River system during glacial episodes and subsequent infilling by fluvial-estuarine-barrier island sediment sequences during interglacial transgressions. Unraveling the Holocene time slice will help reconstruct complex Quaternary records of multiple incisement and backfilling. A network of drill holes, vibracores, and seismic data suggest a four-phase infill history over the last 12,000 years. (1) Lower Roanoke River: (a) Bedload-charged, braided fluvial systems deposited basal sequences of sand and gravel prior to [approximately]5,000 BP. (b) Aggradational, swamp-forest floodplains developed [approximately]5,000 BP and bound the modern incised channels characterized by minimal bedload sedimentation. (2) Albemarle sound: (a) In the central basin, the basal channel sand sequence is overlain by an open estuarine, highly interlaminated sand and mud sequence that accumulated between [approximately]12,000 BP and [approximately]2,000 BP. (b) Depositional patterns within this unit suggest multiple oscillations of Holocene sea level that caused channel reincisement and subsequent backfilling. (c) Present estuarine marsh sedimentation began in protected coastal areas [approximately]5,000 BP. (3) Outer banks: (a) Barrier islands first influenced sedimentation in the area after [approximately]5,000 BP producing a semi-enclosed Albemarle Sound. (b) Deposition within the central basin shifted to uniform organic-rich muds that grade eastward into overwash and inlet sands. (4) Modern man: (a) colonial development within the drainage basins in the early 1700's AD produced a wedge of orange mud in inner Albemarle Sound. (b) Dam construction in the 1950's terminated orange mud deposition and the central basin reverted to organic-rich mud sedimentation.

  19. Formation of Pedogenic Carbonates in the Semi-arid Rio Grande Valley: Insights from Carbon, Major elements, and U-series isotopes in Natural and Agricultural Soils of Southern New Mexico and Western Texas

    NASA Astrophysics Data System (ADS)

    Nyachoti, S. K.; Ma, L.; Jin, L.; Tweedie, C. E.

    2013-12-01

    Accumulation of pedogenic carbonates in arid and semi-arid soils affects soil porosity, water infiltration, and global carbon cycle. We investigate formation rates of these carbonates under different land uses in the semi-arid Rio Grande valley using mineralogy, concentrations of major elements (including C), and U-series isotopes. Our study sites include one alfalfa farm (Alfalfa) at El Paso, TX under frequent irrigation with saline water from the Rio Grande River, and one natural shrub field under natural rainfall conditions at the USDA Jornada Experimental Range (Jornada) in NM. Major minerals observed at Alfalfa and Jornada are calcite, quartz, and feldspars. Calcite/quartz ratios increase upward in the profile at Alfalfa, suggesting formation of carbonates in shallow soils. Consistently, total carbon increases toward the soil surface at Alfalfa, contributed by both soil organic carbon and soil inorganic carbon (pedogenic carbonates). Concentrations of major elements (e.g Ca, Mg, and Sr) also increase toward the surface at Alfalfa, suggesting surface addition. Alternating trends of enrichment and depletion are observed throughout the soil profiles. In contrast, calcite/quartz ratios decrease toward the surface at Jornada, indicative of leaching at shallow soils and redeposition of calcite at depth. This is in agreement with high soil inorganic carbon contents measured at depth. At Jornada however, the Ca, Mg and Sr concentrations decrease toward the surface, showing typical depletion profiles. (234U/238U) activity ratios in bulk soils increase upward at Alfalfa while at Jornada (234U/238U) ratios decrease toward the surface. (234U/238U) ratios at Alfalfa suggest surface addition of U onto shallow soils probably from irrigation water, which is known to have high (234U/238U) ratios. Jornada shows preferential loss of 234U upward. U-series disequilibrium in pedogenic carbonates enables calculation of their formation ages. At Alfalfa, carbonate ages range from 2

  20. Evaluating airborne hyperspectral imagery for mapping saltcedar infestations in west Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rio Grande of west Texas contains by far the largest infestation of saltcedar (Tamarix spp.) in Texas. The objective of this study was to evaluate airborne hyperspectral imagery and different classification techniques for mapping saltcedar infestations. Hyperspectral imagery with 102 usable band...

  1. Using airborne hyperspectral imagery for mapping saltcedar infestations in west Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Rio Grande of west Texas contains, by far, the largest infestation of saltcedar (Tamarix spp.) in Texas. The objective of this study was to evaluate airborne hyperspectral imagery and different classification techniques for mapping saltcedar infestations. Hyperspectral imagery with 102 usable ba...

  2. The 1968 Edcouch-Elsa High School Walkout: Chicano Student Activism in a South Texas Community

    ERIC Educational Resources Information Center

    Barrera, James B.

    2004-01-01

    A nonviolent school boycott by 192 Chicanola students in 1968 at Edcouch-Elsa high school in the Rio Grande Valley region of Deep South Texas is examined. This walkout was the first major Chicano student protest in South Texas, and was a product of the 1960s Chicano movement.

  3. A new tool to assess groundwater resources in the Mississippi embayment

    USGS Publications Warehouse

    Clark, Brian R.; Freiwald, David A.

    2011-01-01

    What is the Mississippi Embayment? The Mississippi embayment study area encompasses approximately 78,000 square miles in eight States and includes large parts of Arkansas, Louisiana, Mississippi, and Tennessee, and smaller areas of Alabama, Illinois, Kentucky, and Missouri (fig. 1). The Mississippi embayment is essentially a basin that slopes toward the Gulf of Mexico and is filled with sediments of alternating sand, silt, and clay layers. There are two principal aquifers in the embayment-the Mississippi River Valley alluvial aquifer (alluvial aquifer) and the middle Claiborne aquifer (fig. 1). The shallow alluvial aquifer is the primary source of groundwater for irrigation in the largely agricultural region, while the deeper middle Claiborne aquifer is a primary source of drinking water for many of the 5.2 million people living in the embayment. The U.S. Geological Survey (USGS) is conducting large-scale multidisciplinary regional studies of groundwater availability for the Nation. Studies comprise individual assessments of regional groundwater-flow systems that encompass varied terrains and document a comprehensive regional and national perspective of groundwater resources. Collectively, these studies are the foundation for the national assessment of groundwater availability and are conducted in cooperation with other Federal, State, local governments, and the private sector. Numerical groundwater-flow models are used in these studies to document effects of human activities and climate variability on groundwater levels, changes in aquifer storage, and flow between groundwater and surface-water bodies. As part of the Mississippi Embayment Regional Aquifer Study (MERAS), a numerical model was constructed of 13 layers over 78,000 square miles representing multiple aquifers and confining units for the period of 1870 to 2007. The model is a tool that was used to assess and better understand groundwater resources.

  4. Coastal loading and transport of Escherichia coli at an embayed beach in Lake Michigan

    USGS Publications Warehouse

    Ge, Z.; Nevers, M.B.; Schwab, D.J.; Whitman, R.L.

    2010-01-01

    A Chicago beach in southwest Lake Michigan was revisited to determine the influence of nearshore hydrodynamic effects on the variability of Escherichia coli (E. coli) concentration in both knee-deep and offshore waters. Explanatory variables that could be used for identifying potential bacteria loading mechanisms, such as bed shear stress due to a combined wave-current boundary layer and wave runup on the beach surface, were derived from an existing wave and current database. The derived hydrodynamic variables, along with the actual observed E. coli concentrations in the submerged and foreshore sands, were expected to reveal bacteria loading through nearshore sediment resuspension and swash on the beach surface, respectively. Based on the observation that onshore waves tend to result in a more active hydrodynamic system at this embayed beach, multiple linear regression analysis of onshore-wave cases further indicated the significance of sediment resuspension and the interaction of swash with gull-droppings in explaining the variability of E. coli concentration in the knee-deep water. For cases with longshore currents, numerical simulations using the Princeton Ocean Model revealed current circulation patterns inside the embayment, which can effectively entrain bacteria from the swash zone into the central area of the embayed beach water and eventually release them out of the embayment. The embayed circulation patterns are consistent with the statistical results that identified that 1) the submerged sediment was an additional net source of E. coli to the offshore water and 2) variability of E. coli concentration in the knee-deep water contributed adversely to that in the offshore water for longshore-current cases. The embayed beach setting and the statistical and numerical methods used in the present study have wide applicability for analyzing recreational water quality at similar marine and freshwater sites. ?? 2010 American Chemical Society.

  5. Modern foraminifera assemblages in the Amundsen Sea Embayment

    NASA Astrophysics Data System (ADS)

    Ewa Jernas, Patrycja; Kuhn, Gerhard; Hillenbrand, Claus-Dieter; Lander Rasmussen, Tine; Forwick, Matthias; Mackensen, Andreas; Schröder, Michael; Smith, James; Klages, Johann Philipp

    2015-04-01

    The West Antarctic Ice Sheet (WAIS) is considered the most unstable part of the Antarctic Ice Sheet. As the WAIS is mostly grounded below sea level, its stability is of great concern. A collapse of large parts of the WAIS would result in a significant global sea-level rise. At present, the WAIS shows dramatic ice loss in its Amundsen Sea sector, especially in Pine Island Bay. Pine Island Glacier (PIG) is characterised by fast flow, major thinning and rapid grounding-line retreat. Its mass los over recent decades is generally attributed to melting caused by the inflow of warm Circumpolar Deep Water (CDW). Future melting of PIG may result in a sea level tipping point, because it could trigger widespread collapse of the WAIS, especially when considering ongoing climate change. Our research project aims to establish proxies (integration of foraminifera, sediment properties and oceanographic data) for modern environmental conditions by analysing seafloor surface sediments along a transect from the glacier proximal settings to the middle-outer shelf in the eastern Amundsen Sea Embayment. These proxies will then be applied on sediment records spanning the Holocene back to the Last Glacial Maximum for reconstructing spatial and temporal variations of CDW upwelling and ice-ocean interactions during the past c. 23,000 years. We will present preliminary results from the analyses of ten short marine sediment cores (multi and box cores) collected during expeditions JR179 (2008) and ANT-XXVI/3 (2010) along a transect from inner Pine Island Bay to the middle-outer shelf part of the Abbot Palaeo-Ice Stream Trough at water depths ranging from 458 m (middle shelf) to 1444 m (inner shelf). The sediment cores are currently investigated for distribution patterns of planktonic and benthic foraminifera and grain-size distribution at 1 cm resolution. Core tops (0-10 cm) were stained with Rose Bengal for living benthic foraminifera investigations. The chronology of the cores will be based

  6. Estimation of residence time in a shallow lacustrine embayment

    NASA Astrophysics Data System (ADS)

    Razmi, A. M.; Barry, D. A.; Lemmin, U.; Bakhtyar, R.

    2012-12-01

    Near-shore water quality in lacustrine bays subjected to effluent or stream discharges is affected by, amongst other things, the residence time within a given bay. Vidy Bay, located on the northern shore of Lake Geneva, Switzerland, receives discharge from a wastewater treatment plant, the Chamberonne River and a storm-water drain. The residence time of water in the bay largely depends on water exchanges with the main basin (Grand Lac) of Lake Geneva. Field investigations and modeling of the hydrodynamics of Vidy Bay have shown that currents are variable, due mainly to wind variability over the lake. However, in broad terms there are two main current patterns in the bay, (i) currents are linked to large gyres in the Grand Lac, or (ii) currents are partially independent of the Grand Lac and are controlled by small-scale gyres within the bay. Residence times in Vidy Bay were computed using the hydrodynamic model Delft3D. Since the Vidy Bay shoreline follows a shallow arc, the definition of the off-shore extent of the bay is ambiguous. Here, the largest within-bay gyre is used. Particle tracking was conducted for each of the three discharges into the bay. Model results were computed using meteorological data for 2010, and thus include the natural variability in wind patterns and seasonal stratification. An analysis of the results shows that a water parcel from the waste water outfall has a residence time ranging from hours to days. The water residence time is minimum near to the surface and maximum at the near bottom layer. The results confirmed that wind force, thermal stratification, and water depth are the main factors influencing residence time.

  7. The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.

    ERIC Educational Resources Information Center

    Ruffing, Jenny

    The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

  8. Structural features of eastern Tejon embayment from available seismic and subsurface data and field geology

    SciTech Connect

    Goodman, E.D.; Malin, P.E.

    1988-03-01

    The temporal and spatial relationships of normal, thrust, and strikeslip faults in the eastern Tejon embayment were investigated, and an integrated study of new CALCRUST data, industrial seismic data, well data, and surface geology yielded a set of geologic cross sections and a detailed structure map. Buried normal faults, trending northeast, dominate the central embayment structure. At the basin margins, the normal faults are truncated by younger thrust faults. The Springs fault zone is a complex subvertical fault with branching reverse faults. The White Wolf fault is probably segmented and multistranded. The active, lower angle segment of the White Wolf fault may be related to buried thrust faults west of uplifted Comanche Point. Thrust faulting also may explain the presence of exhumed normal faults at Comanche Point and in the Tehachapi foothills. These exhumed normal faults are probably late Oligocene to Pliocene. The Tunis volcanics formed during a period of widespread late Oligocene-early Miocene volcanism in central California. Volcanism and the inception of normal faulting at Tejon embayment apparently predated the passing of the Mendocino triple junction. Younger volcanic rocks are also widely distributed, probably due to regional transtension that occurred south of the Mendocino triple junction. Seismic data suggest that the deepening of Tejon embayment occurred mainly during the late early and middle Miocene. Convergence beginning during the Pliocene-Pleistocene is consistent with other documented changes along the modern San Andreas fault.

  9. RELATIONSHIPS BETWEEEN NITROGEN LOADING AND CONCENTRATIONS OF NITROGEN AND CHLOROPHYLL IN COASTAL EMBAYMENTS

    EPA Science Inventory

    We describe results obtained with a simple model that uses loading rates of total nitrogen (TN), defined as dissolved inorganic nitrogen plus dissolved and particulate organic nitrogen, to calculate annually and spatially averaged concentrations of TN in coastal embayments. We al...

  10. Early Monitoring Approaches Developed from a Case Study on a Vulnerable Great Lakes Embayment

    EPA Science Inventory

    Great Lakes harbors/embayments are at high risk of introduction of invasive species. Monitoring is needed to inform on new introductions, and to track success of programs to limit invasion or spread. A field case study was conducted in the Duluth-Superior Harbor/St. Louis River, ...

  11. Robust Segmentation of Embayments to Encompass Exposure and Changes in Constituent Load

    EPA Science Inventory

    Nutrient and contaminant loads from the watershed, atmosphere, and seaward boundary to an embayment continually change due to human activities and alterations in the trends of natural forcing. Nevertheless, residence time (a measure of exposure) is always viewed as an unchanging ...

  12. Shoreface storm morphodynamics and mega-rip evolution at an embayed beach: Bondi Beach, NSW, Australia

    NASA Astrophysics Data System (ADS)

    McCarroll, R. Jak; Brander, Robert W.; Turner, Ian L.; Leeuwen, Ben Van

    2016-03-01

    Embayed beach dynamics differ from open beaches due to the nature of headland control. Their resultant morphologies and morphodynamic behaviour are poorly understood due in part to a critical lack of surfzone and nearshore bathymetry observations. This study describes the morphodynamic storm response of a high-energy intermediate, 850 m long embayed beach over a three week period spanning a cluster of storms. A headland and subaqueous ridge protects the northern end of the beach, resulting in an alongshore wave height gradient. Contrary to existing beach state conceptual models, under energetic forcing the beach did not 'reset' or enter a 'cellular mega-rip' beach state. The protected northern end persisted in a low energy state, while the wave exposed southern section transitioned from transverse-bar-and-rip to a complex double-bar system, a process previously undescribed in the literature. Bar-rip morphology at the exposed end of the beach migrated offshore to greater depths, leaving an inner-reflective beach and longshore trough, while a mega-rip channel with 3 m relief developed at the exposed headland. The number of rip channels remained near constant over multiple storm events. Offshore sediment flux was 350 m3/m at the exposed headland and 20 m3/m at the protected end. Alongshore bathymetric non-uniformity decreased over the sub-aerial beach and inner surfzone, but increased in the outer surfzone and beyond. Suggested mechanisms for the persistence of 3D morphology during the cluster of storms include: (i) wave refraction to shore normal within the embayment; (ii) alongshore energy gradients; and (iii) pre-existing bar-rip morphology. Formation of the complex multi-bar state may be related to antecedent morphology, headland geometry, substrate gradient and localised hydrodynamic interactions near the headland. A new conceptual embayed beach state model is proposed for asymmetric, transitional embayed beaches. The model describes a pre-storm embayment where

  13. Growth of Mexican-American Children in South Texas.

    ERIC Educational Resources Information Center

    Guinn, Bobby; Crofts, Alfred

    Height, weight, and triceps skinfold were measured in 1,680 Mexican American children, 10 through 14 years of age, from the Lower Rio Grande Valley (LRGV) region of Texas. Study sample measurements were compared to those gathered in 1972 involving LRGV Mexican American children as well as National Center for Health Statistics (NCHS) reference data…

  14. Bulk sediment Qp and Qs in the Mississippi embayment, central United States

    USGS Publications Warehouse

    Langston, C.A.; Bodin, P.; Powell, C.; Withers, M.; Horton, S.; Mooney, W.

    2005-01-01

    We have estimated P-wave and S-wave anelastic attenuation coefficients for the thick, unconsolidated sediments of the Mississippi embayment, central United States, using the spectral distance decay of explosion P and Rayleigh waves. The sediment-trapped P wave, Psed, is observed to ranges of 80 km at 10 Hz, and 1-Hz Rayleigh waves are observed out to 130 km from a 5000-lb borehole explosion in the northern part of the embayment. Rayleigh waves of 4 Hz are seen to distances of 3 km from a smaller 50-lb explosion. Analysis of the group velocity and amplitude-distance decay of both waves yields an average Qs of 100 and Qp of 200 for embayment sediments that are independent of frequency. Scatter in the Q estimates comes from interference of multiple P-wave reverberations and Rayleigh-wave modes. The attenuation model is self-consistent in that it is the same as obtained by the analysis of synthetic seismograms using the inferred Q-values. Inferred Qp and Qs values are more than three times higher than previous estimates and imply that unconsolidated sediments of the embayment do not significantly attenuate small-strain earthquake ground motions. These estimates represent a lower bound to Q of the sediments since significant scattering is observed in the waveform data that contributes to the distance decay of wave amplitude. Higher Q values also imply that the unconsolidated sediments of the embayment will form an efficient wave guide for surface waves radiated from shallow earthquakes or large earthquakes that rupture into the sediments, producing high-amplitude, long-duration wave trains that should be considered in earthquake hazard assessments.

  15. Volcanically embayed craters on Venus: testing the catastrophic and equilibrium resurfacing models

    NASA Astrophysics Data System (ADS)

    Ivanov, M. A.; Head, J. W.

    2015-02-01

    Two major types of volcanic units, older regional plains and younger lobate plains, make up ~50% of the surface of Venus and represent different epochs of volcanism. The abundance of impact craters partially embayed from the exterior by each of these two types of units permits the testing of the key points of the model of equilibrium resurfacing. The proportion of craters embayed by the older regional plains is ~3%, which requires the typical size of a volcanic resurfacing event to be ~2700 km (~25° of angular diameter) in the framework of the equilibrium model. These event dimensions are inconsistent with the quasi-random spatial distribution of the craters. The proportion of craters embayed by younger lobate plains is 33%, which can be achieved if the characteristic size of the resurfacing event is less than ~160 km (~1.5° of angular diameter). Events of this size do not disturb the character of the spatial distribution of craters. We conclude that the style of volcanic resurfacing on Venus has changed significantly during its observable portion of the geologic history. During the global volcanic regime when regional plains were emplaced, volcanism acted in large regions and the process of formation of regional plains was more intensive than accumulation of impact craters. This led to the very small proportion of embayed craters (~3%). Later, during the network-rifting and volcanism regime (emplacement of lobate plains), volcanic sources were localized at distinctive centers, the net volcanic intensity decreased and became comparable to the rate of accumulation of craters, which resulted in much larger percentage (33%) of craters embayed by lobate plains.

  16. Hyacinths Choke the Rio Grande

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), flying aboard NASA's Terra satellite, demonstrate the potential of satellite-based remote sensors to monitor infestations of non-native plant species. These images show the vigorous growth of water hyacinths along a stretch of the Rio Grande River in Texas. The infestation had grown so dense in some places it was impeding the flow of water and rendered the river impassible for boats. The hyacinth is an aquatic weed native to South America. The plant is exotic looking and, when it blooms, the hyacinth produces a pretty purple flower, which is why it was introduced into North America. However, it has the capacity to grow and spread at astonishing rates so that in the wild it can completely clog the flow of rivers and waterways in a matter of days or weeks. The top image was acquired on March 30, 2002, and the bottom image on May 9, 2002. In the near-infrared region of the spectrum, photosynthetically-active vegetation is highly reflective. Consequently, vegetation appears bright to the near-infrared sensors aboard ASTER; and water, which absorbs near-infrared radiation, appears dark. In these false-color images produced from the sensor data, healthy vegetation is shown as bright red while water is blue or black. Notice a water hyacinth infestation is already apparent on March 30 near the center of the image. By May 9, the hyacinth population has exploded to cover more than half the river in the scene. Satellite-based remote sensors can enable scientists to monitor large areas of infestation like this one rather quickly and efficiently, which is particularly useful for regions that are difficult to reach from on the ground. (For more details, click to read Showdown in the Rio Grande.) Images courtesy Terrametrics; Data provided by the ASTER Science Team

  17. Texas Heart Institute

    MedlinePlus

    ... Join us! James T. Willerson MD Cardiovascular Seminar Texas Heart Institute Journal Scientific Publications Library & Learning Resources ... Education 12th Annual Diabetes Symposium September 17, 2016 Texas Heart Institute Program Director: Mandeep Bajaj, MD Clinical ...

  18. East Texas Storytellers.

    ERIC Educational Resources Information Center

    Anderson, Brandi, Ed.

    1987-01-01

    Written and published by the students at Gary High School, Gary, Texas, "Loblolly Magazine" is published twice a year. Issues are frequently devoted to a distant theme. The theme of this issue, "East Texas Storytellers," attempts to capture some of the local color and regional history of eastern Texas. The first article, "Timothy Griffith, Master…

  19. Treasured Texas Theaters

    ERIC Educational Resources Information Center

    Horton, Anita

    2012-01-01

    Dallas artist Jon Flaming's deep love of Texas is evident in his paintings and sculpture. Although he has created one sculptural Texas theater, his work primarily showcases old Texas barbershops, vacant homes, and gas stations. In this article, the author describes how her students, inspired by Flaming's works, created three-dimensional historical…

  20. TENET: Texas Education Network.

    ERIC Educational Resources Information Center

    Stout, Connie

    The Texas Education Agency sought to create an enhanced electronic communications network (TENET) capable of transmitting information among and between the members of the public education system in Texas. They contracted with the Texas Higher Education Network (THEnet), an existing distributed network which is an NSF (National Science Foundation)…

  1. Penokean tectonics along a promontory-embayment margin in east-central Minnesota

    USGS Publications Warehouse

    Chandler, V.W.; Boerboom, Terrence; Jirsa, M.A.

    2007-01-01

    Recent geologic investigations in east-central Minnesota have utilized geophysical data, test drilling, and high-resolution geochronologic dating to produce a significantly improved map of a poorly exposed part of the 1880-1830 Ma Penokean orogen. These investigations have elucidated major changes in the structure of the orogen, as compared to its counterparts in northern Michigan and northwestern Wisconsin. Foreland basin, fold and thrust belt, and magmatic terrane components that are recognized to the east extend into east-central Minnesota, but they appear to be deflected southwards and truncated in proximity to Archean rocks of the Minnesota River Valley (MRV) subprovince. In contrast, the interior of the MRV subprovince to the southwest shows little sign of Penokean tectonism. In addition, the magmatic and metamorphic rocks of the internal zone of the orogen in east-central Minnesota are extensively invaded by ca. 1785-1770 Ma granitic rocks (the East-Central Minnesota Batholith), whereas, post-orogenic granites of this age occur sparingly to the east. These differences in orogenic structure may be related to their location near the juncture of an embayment (Becker embayment) and a promontory (MRV promontory) that formed the pre-Penokean continental margin. In this scenario, the MRV promontory, which at the surface consists chiefly of high-metamorphic-grade Mesoarchean gneisses, would have formed competent, high-standing crust that resisted deformation and did not host significantly thick continental margin sequences. In contrast, the part of the Becker Embayment adjoining the promontory would have involved relatively weak, low-standing crust that favored deposition of continental margin sequences and, during Penokean collision, would have accommodated tectonic loading of the cratonic margin through thin-skinned deformation. Thrusting of thick embayment sequences and possibly a block of Archean crust (Marshfield terrane) onto the embayment margin may have

  2. Micropaleontologic record of Quaternary paleoenvironments in the Central Albemarle Embayment, North Carolina, U.S.A.

    USGS Publications Warehouse

    Culver, Stephen J.; Farrell, Kathleen M.; Mallinson, David J.; Willard, Debra A.; Horton, Benjamin P.; Riggs, Stanley R.; Thieler, E. Robert; Wehmiller, John F.; Parham, Peter; Snyder, Scott W.; Hillier, Caroline

    2011-01-01

    To understand the temporal and spatial variation of eustatic sea-level fluctuations, glacio-hydro-isostacy, tectonics, subsidence, geologic environments and sedimentation patterns for the Quaternary of a passive continental margin, a nearly complete stratigraphic record that is fully integrated with a three dimensional chronostratigraphic framework, and paleoenvironmental information are necessary. The Albemarle Embayment, a Cenozoic regional depositional basin in eastern North Carolina located on the southeast Atlantic coast of the USA, is an ideal setting to unravel these dynamic, interrelated processes.Micropaleontological data, coupled with sedimentologic, chronostratigraphic and seismic data provide the bases for detailed interpretations of paleoenvironmental evolution and paleoclimates in the 90. m thick Quaternary record of the Albemarle Embayment. The data presented here come from a transect of cores drilled through a barrier island complex in the central Albemarle Embayment. This area sits in a ramp-like setting between late Pleistocene incised valleys.The data document the episodic infilling of the Albemarle Embayment throughout the Quaternary as a series of transgressive-regressive (T-R) cycles, characterized by inner shelf, midshelf, and shoreface assemblages, that overlie remnants of fluvial to estuarine valley-fill. Barrier island and marginal marine deposits have a low preservation potential. Inner to mid-shelf deposits of the early Pleistocene are overlain by similar middle Pleistocene shelf sediments in the south of the study area but entirely by inner shelf deposits in the north. Late Pleistocene marine sediments are of inner shelf origin and Holocene deposits are marginal marine in nature. Pleistocene marine sediments are incised, particularly in the northern half of the embayment by lowstand paleovalleys, partly filled by fluvial/floodplain deposits and in some cases, overlain by remnants of transgressive estuarine sediments. The shallowing

  3. Could narrow marine embayments prevent sea-glacier invasion, and protect photosynthetic life during a Snowball Earth?

    NASA Astrophysics Data System (ADS)

    Campbell, Adam J.

    During the Snowball Earth events of the Neoproterozoic, the Earth's oceans may have been completely covered in ice. This ice would have been thick enough to prohibit the transmission of light to the liquid water underneath the entirely frozen surface of the ocean. However, photosynthetic eukaryotes are thought to have survived during these events. This is the first work to throughly attempt to reconcile how photosynthetic eukaryotes survived on a planet with a completely frozen ocean surface. Narrow marine embayments like the modern-day Red Sea, would restrict the inflow of sea glaciers. These embayments, if located in regions of net sublimation, would restrict sea-glacier invasion and could provide refuge for these organisms at the end of their channels. This work demonstrates that under a set of climate conditions and channel geometries, narrow marine embayments allow for incomplete sea-glacier invasion, a necessary condition for marine embayments to provide refugia.

  4. An Eocene flora from trans-Pecos Texas

    USGS Publications Warehouse

    Berry, Edward Wilber

    1920-01-01

    During the fall of 1916 I received a small collection of fossil plants which had been obtained during a geologic reconnaissance of the trans-Pecos region of Texas, by Charles Lawrence Baker. A preliminary report was sent to Mr. Baker in November of that year and was quoted in his discussion of the geology of that region. I have since made a careful study of the collection, and although it contains only a few species the occurrence of fossil plans in this region is worthy of more definite and detailed record, especially as these plants enabled me to assign a definite age to the beginning of the igneous activity of the region and to establish correlations between the floras of the Mississippi embayment and the Rocky Mountain Region.

  5. Simulating the hydrologic impact of Arundo donax invasion on the headwaters of the Nueces River in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arundo donax (hereafter referred to as Arundo), which is a robust herbaceous plant, has invaded the riparian zones of the Rio Grande River and the rivers of the Texas Hill Country over the last two decades. Arundo was first observed along the Nueces River in central Texas in 1995 by the Nueces Rive...

  6. Migrant Worker: A Boy from the Rio Grande Valley.

    ERIC Educational Resources Information Center

    Hoyt-Goldsmith, Diane

    Ricky is an 11-year-old migrant worker. During the summer, he travels with his family from their home in Rio Grande City, Texas, to farms farther north. There they spend 10-12 hours a day in the hot sun picking fruit and vegetables and packing the harvest for market. Ricky is not protected by the federal laws that govern the hours, wages, and…

  7. Rio Grande rift: An overview

    NASA Astrophysics Data System (ADS)

    Olsen, Kenneth H.; Scott Baldridge, W.; Callender, Jonathan F.

    1987-11-01

    The Rio Grande rift of the southwestern United States is one of the world's principal continental rift systems. It extends as a series of asymmetrical grabens from central Colorado, through New Mexico, to Presidio, Texas, and Chihuahua, Mexico—a distance of more than 1000 km. Although the Rio Grande rift is closely related in timing and structural style to the contiguous Basin and Range extensional province, the two can be distinguished by a variety of geological and geophysical signatures. Rifts (both oceanic and continental) can be defined as elongate depressions overlying places where the entire lithosphere has ruptured in extension. The lithosphere of the Rio Grande rift conforms to this definition, in that: (1) the crust is moderately thinned—Moho depths range from about 45 km under the flanks to about 33 km beneath the rift axis. (2) anomalously low P n velocities (7.6-7.8 km s -1) beneath the rift and a long wavelength gravity low suggest that the asthenosphere is in contact with the base of the crust. The P-velocity is abnormally low (6.4-6.5 km s -1) in the lower half of the crust beneath the rift, suggesting high crustal temperatures. However, associated seismic and volcanologic data indicate the sub-rift lower crust is not dominated by a massive composite mafic intrusion such as is sometimes inferred for the East African rifts. Seismic and magnetotelluric data suggest the presence of a thin (< 1 km) sill-like contemporary midcrustal magma body which may perhaps extend intermittently along much of the length of the rift. Seismic and structural studies indicate a dominant horizontal fabric in the upper and middle crust. The brittle-ductile transition is at depths -15 km except for the major volcanic fields, where it rises to 2-3 km. Structural development of the rift occurred mainly during two time intervals: the early phase beginning at -30 Ma. and lasting 10-12 m.y., and the late phase extending from -10 to 3 Ma. The early phase involved extensive

  8. Statewide summary for Texas

    USGS Publications Warehouse

    Handley, Lawrence R.; Spear, Kathryn A.; Gibeaut, Jim; Thatcher, Cindy

    2014-01-01

    Seafood landed at Texas ports valued $240 million in 2011, and recreational saltwater fishing alone provided nearly 17,000 jobs (Texas GLO, 2013). Fishes directly dependent upon wetland habitats include multiple shrimp species, blue crab, eastern oyster, black drum, flounder, sheepshead, and snapper. Texas has the highest number of hunters, anglers, and hunting expenditures in the nation (U.S. Fish and Wildlife Service, 2012). Hunting yields $2.3 billion for the state, and recreational fishing yields $3.2 billion. Texas is the top birding destination in the Nation. Tourism in Texas generates $7.5 billion for the state, and wildlife viewing generates $2.9 billion.

  9. Another Estimate for the Percentage of Partly Embayed Craters in Equilibrium Resurfacing

    NASA Astrophysics Data System (ADS)

    Muinonen, P. J.

    1996-03-01

    When choosing between different scenarios of Venus' resurfacing history, one of the objections against an Equilibrium Resurfacing Model (ERM) is an apparent lack of craters that have suffered a partial embayment by lava flows of outside origin. Any test of ERM so far, be it numeric or analytic in nature, has failed to predict anything even near the observed ~5% of partly embayed craters (PECs) without violating the statistics of crater distribution. This study is mainly based on straightening out as many as possible of the simplifications that have been employed while estimating the statistical implications of the ERM. As a result, the expectation value for PECs falls to less than 10% from previous ~30%.

  10. MISSISSIPPI EMBAYMENT AQUIFER SYSTEM IN MISSISSIPPI: GEOHYDROLOGIC DATA COMPILATION FOR FLOW MODEL SIMULATION.

    USGS Publications Warehouse

    Arthur, J.K.; Taylor, R.E.

    1986-01-01

    As part of the Gulf Coast Regional Aquifer System Analysis (GC RASA) study, data from 184 geophysical well logs were used to define the geohydrologic framework of the Mississippi embayment aquifer system in Mississippi for flow model simulation. Five major aquifers of Eocene and Paleocene age were defined within this aquifer system in Mississippi. A computer data storage system was established to assimilate the information obtained from the geophysical logs. Computer programs were developed to manipulate the data to construct geologic sections and structure maps. Data from the storage system will be input to a five-layer, three-dimensional, finite-difference digital computer model that is used to simulate the flow dynamics in the five major aquifers of the Mississippi embayment aquifer system.

  11. STEM education for teachers in the Rio Grande Valley

    NASA Astrophysics Data System (ADS)

    Ries, Judit Gyorgyey; Baguio, Margaret R.

    2015-11-01

    We have worked with elementary and middle school teachers in the Rio Grande Valley for the last 10 years bringing Earth and Space Science themed workshops to underserved areas of Texas. The Texas curriculum was also changed to include Astronomy and Space Science requirement in the tests students need to take to prove their academic preparedness. The teachers worked through a variety of inquiry-based, hands-on activities after a short presentation on the background science. In order to evaluate our effectiveness, we have asked the teachers to take pre- and post-workshop tests, and we asked them to fill out a self-reflective survey. We will report on our experiences, what works best with the teachers, and in what areas we still have a long way to go.This work was supported by various NASA education grants and Cooperative agreements, as well as grants provided by the Texas Space Grant Consortium.

  12. Rio Grande pipeline introduces LPG to Mexico

    SciTech Connect

    1997-06-01

    Rio Grande Pipeline, a joint venture between Mid-America Pipeline Co., Amoco Pipeline Co. and Navajo Pipeline Co., has broken new ground in the energy industry as the first LPG pipeline to cross the US-Mexico border. Plans for the project were announced in November 1995 and first deliveries started three months ago on March 21, 1997. The 8-inch, 265-mile pipeline originates near Odessa, TX, where it receives an 85-15 propane-butane mix via a connection to Mid-America Pipeline. From Odessa, product moves west through the Texas desert and crosses the Rio Grande River about 15 miles south of El Paso near Clint, TX and extends 20 miles into Mexico. Capacity of the line is 24,000 bpd and it has been averaging about 22,000 bpd since line-fill. All in all, it sounded like a reasonably feasible, routine project. But perceptions can be deceiving, or at least misleading. In other words, the project can be summarized as follows: one river, two cultures and a world of difference. The official border crossing for pipeline construction took place on Dec. 2, 1996, with a directional drill under the Rio Grande River, but in actuality, the joint venture partners were continually bridging differences in language, laws, customs and norms with Pemex and contracted workers from Mexico.

  13. Burrowing mayflies as indicators of ecosystem health: status of populations in two western Lake Superior embayments

    USGS Publications Warehouse

    Edsall, Thomas A.; Gorman, Owen T.; Evrard, Lori M.

    2004-01-01

    The U.S. Environmental Protection Agency and Environment Canada are supporting the development of indicators of ecosystem health that can be used to report on progress in restoring and maintaining the Great Lakes ecosystem, as called for in the Great Lakes Water Quality Agreement between the United States and Canada. One indicator under development for Great Lakes mesotrophic environments is based on burrowing mayflies ( Hexagenia: Ephemeroptera: Ephemeridae). In this paper, we report the results of a benthic survey in spring 2002 to determine the status of nymphal populations of Hexagenia in two western Lake Superior embayments, the St. Louis River estuary, an area with significant water-use impairments, and Chequamegon Bay, an area with no known water-use impairments. Ponar grab samples collected throughout these embayments showed nymphs were generally abundant in finely particulate, cohesive substrate (clay or mixtures of clay and sand) in both embayments. However, in the St. Louis River estuary nymphs were absent in those preferred substrates at 11 stations in the eastern portion of St. Louis Bay and the adjoining northwestern portion of the Duluth-Superior Harbor, where the sediments were variously contaminated with visible amounts of taconite pellets, paint chips, oil, or combusted coal waste (clinkers). Our results suggest that human activities have rendered those portions of the St. Louis River estuary unsuitable for habitation by Hexagenia nymphs and we recommend that trend monitoring of the nymphal population there be conducted to permit reporting on progress in restoring and maintaining the health and integrity of this Great Lakes ecosystem embayment, consistent with the intent of the Great Lakes Water Quality Agreement.

  14. Correlation of Twin Creek limestone with Arapien shale in Arapien embayment, Utah - preliminary appraisal

    SciTech Connect

    Sprinkel, D.A.; Waanders, G.L.

    1984-07-01

    Striking and important stratigraphic patterns have emerged as a result of recent work during which members of the Twin Creek Limestone were correlated with the Arapien Shale, all of Middle Jurassic age. These correlations, determined first on the basis of electric and lithologic logs, are supported by recent palynologic work. Three distinct dinoflagellate assemblages, assigned to the Bajocian(.), Bathonian, and Callovian stages, form the paleontologic basis for these correlations. The Bajocian(.) assemblage is found in rocks of the Sliderock and Rich Members of the Twin Creek Limestone. The Bathonian assemblage is found in units of the Boundary Ridge and Watton Canyon Members of the Twin Creek, and also in units of the lower Arapien Shale (lower Leeds Creek Member of the Twin Creek of Wyoming). The Callovian assemblage is found in rocks of the upper Arapien (upper Leeds Creek and Giraffe Creek Members of the Twin Creek of Wyoming). Isopach maps, based on these correlations, indicate that most of central Utah was the site of a large marine embayment - the Arapien embayment -that was flanked on the west, south, and east by highlands. The maps also suggest that the ancestral Uinta Mountains, a submerged feature, affected sedimentation as early as Bajocian time, and became a significant barrier from the late Bathonian through Callovian. In central Utah, marine carbonates were deposited in the Arapien embayment during deposition of the Gypsum Spring through Watton Canyon Members of the Twin Creek Limestone. During deposition of the Arapien Shale, a major northward regression occurred; the embayment shrank to form a smaller basin - the Arapien basin - that lay directly south of the ancestral Uinta Mountains. Most of the Arapien Shale is shallow-water deposits that formed in the basin under hypersaline conditions.

  15. Read Across Texas! 2002 Texas Reading Club Manual.

    ERIC Educational Resources Information Center

    Edgmon, Missy; Ferate-Soto, Paolo; Foley, Lelana; Hager, Tina; Heard, Adriana; Ingham, Donna; Lopez, Nohemi; McMahon, Dorothy; Meyer, Sally; Parrish, Leila; Rodriguez-Gibbs, Josefina; Moreyra-Torres, Maricela; Travis, Gayle; Welch, Willy

    The goal of the Texas Reading Club is to encourage the children of Texas to become library users and lifelong readers. This manual was created for the 2002 Texas Reading Club, a program of the Texas State Library and Archives Commission. The theme, "Read Across Texas!" invites children to explore the history, geography, and culture of Texas…

  16. Longitudinal Hydrodynamic Characteristics in Reservoir Tributary Embayments and Effects on Algal Blooms

    PubMed Central

    Dai, Huichao; Mao, Jingqiao; Jiang, Dingguo; Wang, Lingling

    2013-01-01

    Three Gorges Reservoir (TGR) is one of the largest man-made lakes in the world. Since the impoundment in 2003, however, algal blooms have been often observed in the tributary embayments. To control the algal blooms, a thorough understanding of the hydrodynamics (e.g., flow regime, velocity gradient, and velocity magnitude and direction) in the tributary embayments is particularly important. Using a calibrated three-dimensional hydrodynamic model, we carried out a hydrodynamic analysis of a typical tributary embayment (i.e., Xiangxi Bay) with emphasis on the longitudinal patterns. The results show distinct longitudinal gradients of hydrodynamics in the study area, which can be generally characterized as four zones: riverine, intermediate, lacustrine, and mainstream influenced zones. Compared with the typical longitudinal zonation for a pure reservoir, there is an additional mainstream influenced zone near the mouth due to the strong effects of TGR mainstream. The blooms are prone to occur in the intermediate and lacustrine zones; however, the hydrodynamic conditions of riverine and mainstream influence zones are not propitious for the formation of algal blooms. This finding helps to diagnose the sensitive areas for algal bloom occurrence. PMID:23874534

  17. A hydrodynamic modeling study to estimate the flushing rate in a large coastal embayment.

    PubMed

    Lee, Hye Won; Park, Seok Soon

    2013-01-30

    A three-dimensional hydrodynamics model was applied to a coastal embayment on the west coast of the Korean Peninsula to examine the potential effects of a large reclamation project (the Saemangeum Project). To understand and analyze the impacts of the coastal structures associated with the Project on the hydrodynamics, as well as the composition ratio of the saltwater to freshwater, the seasonal distribution of the residence time and flushing rate were examined using the salinity and tracer simulation as dilution indicators. The calibrated and verified model was used to examine changes in the tidal elevation, salinity, residence time and flushing rate. The results indicate that the completion of the fourth sea dike will limit circulation, and that the salinity inside the dike would be dominated by rainfall and runoff. The flushing rate was estimated to decrease after the construction of the dike, such that biogeochemical changes could occur in the sea water and sediment. From this study, it was concluded that the three-dimensional hydrodynamic model can successfully simulate the changes in elevation, residence time and flushing rate in the Saemangeum Embayment and become a useful tool for determining a management plan to maintain the water quality of coastal embayments. PMID:23291376

  18. Three-dimensional long-period groundmotion simulations in the upper Mississippi embayment

    USGS Publications Warehouse

    Macpherson, K.A.; Woolery, E.W.; Wang, Z.; Liu, P.

    2010-01-01

    We employed a 3D velocity model and 3D wave propagation code to simulate long-period ground motions in the upper Mississippi embayment. This region is at risk from large earthquakes in the New Madrid seismic zone (NMSZ) and observational data are sparse, making simulation a valuable tool for predicting the effects of large events. We undertook these simulations to estimate the magnitude of shaking likely to occur and to investigate the influence of the 3D embayment structure and finite-fault mechanics on ground motions. There exist three primary fault zones in the NMSZ, each of which was likely associated with one of the main shocks of the 1811-12 earthquake triplet. For this study, three simulations have been conducted on each major segment, exploring the impact of different epicentral locations and rupture directions on ground motions. The full wave field up to a frequency of 0.5 Hz is computed on a 200 ?? 200 ?? 50-km 3 volume using a staggered-grid finite-difference code. Peak horizontal velocity and bracketed durations were calculated at the free surface. The NMSZ simulations indicate that for the considered bandwidth, finite-fault mechanics such as fault proximity, directivity effect, and slip distribution exert the most control on ground motions. The 3D geologic structure of the upper Mississippi embayment also influences ground motion with indications that amplification is induced by the sharp velocity contrast at the basin edge.

  19. Stratigraphy and structure along the Pensacola Arch/Conecuh Embayment margin in northwest Florida

    SciTech Connect

    Duncan, J.G. . Geology Dept. Florida Geological Survey, Tallahassee, FL )

    1993-03-01

    Stratigraphic and structural analysis of deep borehole data along the Pensacola Arch/Conecuh Embayment margin in eastern Santa Rosa County, Florida reveals a northeast-trending basement normal fault that is downthrown to the northwest. The fault functioned as a border fault of a half-graben (or graben ) that developed during continental rifting of Pangea in the Late Triassic and Early Jurassic. The upthrown or horst block was a paleotopographic high that formed the southeastern boundary of the Middle to Late Jurassic Conecuh Embayment. A second, younger basement fault trends approximately perpendicular to the half-graben border fault. Late Triassic synrift continental sediments, deposited on the downthrown block of the half-graben, pinch-out abruptly to the southeast pre-Mesozoic Suwannee Basin basement. The border fault is located approximately where the Triassic sedimentary wedge pinches out. Middle to Upper Jurassic drift-stage strata of the Conecuh embayment progressively onlap the post-rift unconformity toward the southeast. Upper Jurassic Smackover Formation carbonates and evaporites apparently overstep Triassic deposits and rest directly on Suwannee Basin quartzitic sandstone near their depositional limit at the Pensacola Arch. The Smackover Formation thins significantly toward the southeast in association with the Triassic pinch-out and half-graben border fault. The pinch-out trend of the Smackover Formation suggests a northeast-southwest orientation for the Triassic border fault and supports a horst-block origin for the Pensacola Arch.

  20. Late Wisconsin and early holocene glacial history, inner Ross Embayment, Antarctica

    NASA Technical Reports Server (NTRS)

    Denton, George H.; Bockheim, James G.; Wilson, Scott C.; Stuiver, Minze

    1991-01-01

    Lateral drift sheets of outlet glaciers that pass through the Transantarctic Mountains constrain past changes of the huge Ross ice drainage system of the Antarctic Ice Sheet. Drift stratigraphy suggests correlation of Reedy III (Reedy Glacier), Beardmore, Britannia (Hatherton/Darwin Glaciers), Ross Sea (McMurdo Sound), and younger (Terra Nova Bay) drifts; radiocarbon dates place the outer limits of Ross Sea drift in late Wisconsin time at 24,000 to 13,000 yr B.P. Outlet glacier profiles from these drifts constrain late Wisconsin ice sheet surface elevations. Within these constraint, two extreme late Wisconsin reconstructions are given of the Ross ice drainage system. Both show little elevation change of the polar plateau coincident with extensive ice shelf grounding along the inner Ross Embayment. However, in the central Ross Embayment, one reconstruction shows floating shelf ice, where as the other shows a grounded ice sheet. Massive late Wisconsin/Holocene recession of grounded ice from the western Ross Embayment, which was underway at 13,040 yr B.P. and completed by 6600 to 6020 yr B.P., was accompanied by little change in plateau ice levels inland of the Transantarctic Mountains.

  1. John Holt Stanway: Gone to Texas

    NASA Astrophysics Data System (ADS)

    Bryan, J.

    2008-01-01

    John Holt Stanway (1799Ð1872) was an amateur astronomer who lived in Manchester, England until 1845. He was in contact with the English Ôgrand amateurÕ astronomer, William Henry Smyth, who supported him for Fellowship of the Royal Astronomical Society and evidently advised him on how to build and equip an observatory. Apparently, Stanway had an observatory at Chorlton-cum-Hardy in 1837. In 1845, Stanway left for the United States in response to serious business problems. En route, he met Ashbel Smith, a representative of the government of the Republic of Texas, who convinced Stanway to go to Texas. There he changed his name to John H. Smythe Stanley and settled in Houston, where he re-established his observatory. He became a commercial photographer and wrote about astronomy and other scientific subjects in Houston newspapers until his death in 1872.

  2. Coastal evolution between two giant rivers: The Chan May embayment in central Vietnam

    NASA Astrophysics Data System (ADS)

    Gouramanis, C.; Switzer, A.; Bristow, C.; Pham, D. T.; Mauz, B.; Pile, J.; Doan, L. D.; Hoang, Q. D.; Ngo, C. K.; Dao, N.; Polivka, P.; Soria, L.; Lee, Y.; Sloss, C.; Hoang, L. V.

    2015-12-01

    The coastal landscapes of Vietnam are dominated in the north and south by the very large Red and Mekong rivers. Central Vietnam, in contrast, has few large rivers that flow to the coastal zone. This coupled with the high relief (>1500 m) of the granitic Truong Son Range and shallow gradient continental shelf, has produced two different coastal geomorphologies. The first is a shallow basin infilled with a sequence of parallel, arcuate beach ridges, and the second includes the development of shore-parallel spits and coastal lagoons. All systems are Holocene in age and we present evidence of the Holocene evolution of the northward-facing, beach ridge strandplain located in the Chan May embayment, approximately 35 km north of Danang. This embayment is relatively small (5 km long at the beach and with a beach ridge sequence that spans 11 km from the modern beach to the base of the Truong Son Range) compared to other beach ridge strandplains to the north and south and serves as an analogue for the evolution of these larger systems. The Holocene evolution of the embayment was resolved using Ground Penetrating Radar (GPR), high-resolution sedimentological analysis and quartz Optically Stimulated Luminescence were used to investigate the internal stratigraphy and chronological development of the beach ridges at Chan May. The strandplain contains uniform, clean quartz-rich sediment interspersed by thin heavy mineral rich bands forming shallow-gradient beach ridges that have steadily prograded seaward during the regression after the mid-Holocene sea level highstand. As the beach ridges prograded seaward, a small river feeding directly from the Truong Son Range meandered across the strandplain and significantly modified the embayment. Recently, the river has become much reduced due to anthropogenic modification of the river and landscape. Prior to the Holocene marine highstand, the area was similarly characterized by a surface of prograding beach ridges that were eroded by

  3. Potentiometric Surface in the Sparta-Memphis Aquifer of the Mississippi Embayment, Spring 2007

    USGS Publications Warehouse

    Schrader, T.P.

    2008-01-01

    The most widely used aquifer for industry and public supply in the Mississippi embayment in Arkansas, Louisiana, Mississippi, and Tennessee is the Sparta-Memphis aquifer. Decades of pumping from the Sparta-Memphis aquifer have affected ground-water levels throughout the Mississippi embayment. Regional assessments of water-level data from the aquifer are important to document regional water-level conditions and to develop a broad view of the effects of ground-water development and management on the sustainability and availability of the region's water supply. This information is useful to identify areas of water-level declines, identify cumulative areal declines that may cross State boundaries, evaluate the effectiveness of ground-water management strategies practiced in different States, and identify areas with substantial data gaps that may preclude effective management of ground-water resources. A ground-water flow model of the northern Mississippi embayment is being developed by the Mississippi Embayment Regional Aquifer Study (MERAS) to aid in answering questions about ground-water availability and sustainability. The MERAS study area covers parts of eight states including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee and covers approximately 70,000 square miles. The U.S. Geological Survey (USGS) and the Mississippi Department of Environmental Quality Office of Land and Water Resources measured water levels in wells completed in the Sparta-Memphis aquifer in the spring of 2007 to assist in the MERAS model calibration and to document regional water-level conditions. Measurements by the USGS and the Mississippi Department of Environmental Quality Office of Land and Water Resources were done in cooperation with the Arkansas Natural Resources Commission; the Arkansas Geological Survey; Memphis Light, Gas and Water; Shelby County, Tennessee; and the city of Germantown, Tennessee. In 2005, total water use from the Sparta

  4. Temporal slip rate variability in the Lower Rhine Embayment, Northwest Europe

    NASA Astrophysics Data System (ADS)

    Gold, Ryan; Kuebler, Simon; Friedrich, Anke

    2016-04-01

    Low strain regions may be characterized by long periods of seismic quiescence, punctuated by periods of clustered earthquake activity. This type of non-periodic recurrence behavior challenges accurate seismic hazard analysis. The Lower Rhine Embayment in the German-Belgium-Netherland border region presents a unique opportunity to characterize the long-term record of faulting to evaluate the periodicity of earthquake occurrence in a low strain region. The Lower Rhine Embayment is covered by a high-resolution record of Quaternary terraces associated with the Rhine and Maas (Meuse) Rivers and their tributaries. These terraces are cut by numerous NW-trending faults and record cumulative displacements that exceed 100 m in numerous locations. In this study, we exploit this rich record of faulted fluvial terraces and find convincing evidence for temporally varying rates of Quaternary fault movement across the Lower Rhine Embayment. First, we document a significant increase in vertical fault slip rates since 700 ka, compared to the average slip rate since the start of the Quaternary using the top and base of the Main Terrace, respectively. Increases in slip rate exceed 500% along many of the faults, including the Swist/Erft, Stockheim, Viersen, Sandgewand, and Kirspenich fault systems. This increase in fault slip rate corresponds to a regional period of increased tectonic uplift of the Rhenish Massif, increased volcanism in Eifel, and incision of the Rhine River. In a second and related analysis, we synthesize terrace offset and age information from the Feldbiss fault system along the western boundary of the Lower Rhine Embayment, which transects a flight of Quaternary terraces associated with the Mass river. This analysis reveals evidence for secular variation in slip rate. In particular, we identify two periods of higher slip rate (800-400 ka and 130-100 ka), where fault slip rate exceeds the longer-term average slip rate of 0.04-0.05 mm/yr by as much as a factor of two

  5. Transverse section through the Grand Lodge and Grand Chapter rooms ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Transverse section through the Grand Lodge and Grand Chapter rooms of James H. Windrim and George Summers’s neoclassical competition design for the New Masonic Temple, Philadelphia, 1867 - Masonic Temple, 1 North Broad Street, Philadelphia, Philadelphia County, PA

  6. Properties and chemical constituents in ground water from the lower Wilcox Aquifer, Mississippi Embayment Aquifer System, south-central United States

    USGS Publications Warehouse

    Pettijohn, Robert A.; Busby, John F.; Beckman, Jeffery D.

    1993-01-01

    The Gulf Coast Regional Aquifer-System Analysis is a study of regional aquifers composed of sediments of mostly Cenozoic age that underlie about 230,000 sq mi of the Gulf Coastal Plain. These regional aquifers are part of three aquifer systems: (1) the Mississippi Embayment Aquifer System, (2) the Texas Coastal Uplands Aquifer System, and (3) the Coastal Lowlands Aquifer System. The water chemistry of the Lower Wilcox Aquifer, which is part of the Mississippi Embayment Aquifer System is presented by a series of maps. These maps show the areal distribution of (1) the concentration of dissolved solids and temperature, (2) the primary water types and pH, (3) the concentration of major ions and silica, and (4) the milliequivalent ratios of selected ions. Dissolved constituents, pH, temperature, and ratios are based on the median values of all samples in each 100-sq-mi area. The concentration of dissolved solids in water from the Lower Wilcox Aquifer ranges from 18 mg/L near the outcrop in western Tennessee to 122,000 mg/L in a down-dip area in southern Mississippi. The primary water type is calcium bicarbonate in the outcrop area and sodium bicarbonate in all other areas of the aquifer within the limits of available data. The concentrations of major ions generally increase from the outcrop area to the down-dip limit of the data in the southern part of the aquifer area east of the Mississippi River. The milliequivalent ratio maps of selected ions in water from the Lower Wilcox Aquifer indicate some trends. The milliequivalent ratio of magnesium plus calcium to bicarbonate ranges from less than 0.1 to 40.4 and generally decreases from outcrop to down-dip limit of the data in the southern part of the aquifer area east of the Mississippi River. The milliequivalent ratio of bicarbonate to chloride ranges from 0.01 in southern Mississippi to 52.3 in northwestern Mississippi. This ratio increases from the outcrop toward the Mississippi River and from north to south in the

  7. Estimating water use by giant reed along the Rio Grande River using a large aperture scintillometer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is a bamboo-like perennial invasive weed from Eurasia presenting a severe threat to agroecosystems and riparian areas in Texas and Mexican portions of the Rio Grande River Basin. It is known to consume excessive amounts of water to support its rapid vegetative growth rat...

  8. Biological Control of Saltcedar and Giant Reed in the Lower Rio Grande Basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saltcedar (Tamarix spp.) and giant reed (Arundo donax L.) are exotic invasive weeds along the banks of rivers and reservoirs throughout the western U.S. In the Rio Grande Basin of Texas and Mexico, these weeds compete for water resources that are critical for agricultural and urban users and that s...

  9. Grand challenge problems in environmental modeling and remediation: groundwater contaminant transport

    SciTech Connect

    Todd Arbogast; Steve Bryant; Clint N. Dawson; Mary F. Wheeler

    1998-08-31

    This report describes briefly the work of the Center for Subsurface Modeling (CSM) of the University of Texas at Austin (and Rice University prior to September 1995) on the Partnership in Computational Sciences Consortium (PICS) project entitled Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport.

  10. Mapping giant reed along the Rio Grande using airborne and satellite imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is a perennial invasive weed that presents a severe threat to agroecosystems and riparian areas in the Texas and Mexican portions of the Rio Grande Basin. The objective of this presentation is to give an overview on the use of aerial photography, airborne multispectral a...

  11. Economic implications for the biological control of Arundo donax: Rio Grande Basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed, Arundo donax L., is a large bamboo-like plant native to the Mediterranean region. It has invaded several thousand hectares of the Rio Grande riparian habitat in Texas and Mexico. The United States Department of Agriculture-Agricultural Research Service (USDA-ARS) is investigating four ...

  12. A GRAND affair

    NASA Astrophysics Data System (ADS)

    tima2014; tomandersen; mugundhan; toadgreen

    2015-10-01

    In reply to the physicsworld.com news story “GRAND plans for new neutrino observatory”, which called for a new detector made up of hundreds of thousands of antennas spread over an area slightly smaller than the UK (18 August, http://owl.ly/R5N6u).

  13. Earthquake history of Texas

    USGS Publications Warehouse

    von Hake, C. A.

    1977-01-01

    Seventeen earthquakes, intensity V or greater, have centered in Texas since 1882, when the first shock was reported. The strongest earthquake, a maximum intensity VIII, was in western Texas in 1931 and was felt over 1 165 000 km 2. Three shocks in the Panhandle region in 1925, 1936, and 1943 were widely felt. 

  14. Fireball Over Texas

    NASA Video Gallery

    Video of the fireball seen over Texas this morning (12/7/12); it was taken by a NASA camera located near Mayhill, New Mexico. It is very unusual for us to see a meteor all the way across Texas. The...

  15. Understanding the Long-Term Deformation in the Mississippi Embayment: the Mississippi River Seismic Survey

    NASA Astrophysics Data System (ADS)

    Magnani, M.; McIntosh, K.; Waldron, B.; Mitchell, L.; Saustrup, S.; Towle, M.

    2008-12-01

    The Central US hosts one of the most active intraplate seismic areas in the world, the New Madrid seismic zone (NMSZ). Here the high level of historic and instrumental seismicity clashes with the subdued topography of the Mississippi embayment, minimal geodetic vectors and a puzzling lack of substantial deformation in the post Late-Cretaceous sediments. To explain this apparent paradox it has been proposed that the seismicity in the NMSZ is either 1) very young (at least in its present form), 2) episodic, or 3) migrates throughout a broad region. In order to test these hypotheses and to understand how the deformation is partitioned within the Mississippi embayment, we collected a 300 km-long high-resolution seismic reflection profile along the Mississippi river, from Helena, Arkansas to Caruthersville, Missouri. The profile images a portion of the embayment outside the area of influence of the NMSZ in a region where evidence has been mounting of a seismic source, predating the NMSZ, for which no corresponding structure has yet been identified. The seismic survey exploited the advantages of marine acqui9sition (time effective, low cost) using a 245/245 cm3 (15/15 in3) mini-GI airgun fired at 13.790MPa (2000 psi), a 24-channel 75 m-long active streamer, with 3.125 m group and 12 m nominal shot interval. The high quality data image the Cretaceous and younger sedimentary section, from the top of the Paleozoic unconformity to the Quaternary deposits. Preliminary interpretation of the dataset confirms the general deepening of the Paleozoic basement from ~800 ms at Caruthersville, to ~1 s at the southern end of Crowley's Ridge. In addition, the data reveal prominent recent deformation coincident with the Blytheville arch, the Eastern Reelfoot Rift margin and the White river Fault zone, accommodated by folding and faulting that extend from the top of the Paleozoic through the sedimentary section, and that involves the Quaternary deposits.

  16. Intracaldera volcanic activity, Toledo caldera and embayment, Jemez Mountains, New Mexico

    SciTech Connect

    Heiken, G.; Goff, F.; Stix, J.; Shafiqullah, M.; Garcia, S.; Hagan, R.

    1986-02-10

    The Toledo caldera was formed at 1.47 +- 0.06 Ma during the catastrophic eruption of the lower member, Bandelier Tuff. The caldera was obscured at 1.12 +- 0.03 Ma during eruption of the equally voluminous upper member of the Bandelier Tuff that led to formation of the Valles caldera. Earlier workers interpreted a 9-km-diameter embayment, located NE of the Valles caldera (Toledo embayment), to be a remnant of the Toledo caldera. Drill hole data and new K-Ar dates of Toledo intracaldera domes redefine the position of Toledo caldera, nearly coincident with and of the same dimensions as the younger Valles caldera. the Toledo embayment may be of tectonic origin or a small Tschicoma volcanic center caldera. This interpretation is consistent with distribution of the lower member of the Bandelier Tuff and with several other field and drilling-related observations. Explosive activity associated with Cerro Toledo Rhyolite domes is recorded in tuff deposits located between the lower and upper members of the Bandelier Tuff on the northeast flank of the Jemez Mountains. Recorded in the tuff deposits are seven cycles of explosive activity. Most cycles consists of phreatomagmatic tuffs that grade upward into Plinian pumice beds. A separate deposit, of the same age and consisting of pyroclastic surges and flows, is associated with Rabbit Mountain, located on the southeast rim of the Valles-Toledo caldera complex. These are the surface expression of what may be a thicker, more voluminous intracaldera tuff sequence. The combined deposits of the lower and upper members of the Bandelier Tuff, Toledo and Valles intracaldera sediments, tuffs, and dome lavas form what we interpret to be a wedge-shaped caldera fill. This sequence is confirmed by deep drill holes and gravity surveys.

  17. NEHRP soil classifications for estimating site-dependent seismic coefficients in the Upper Mississippi Embayment

    USGS Publications Warehouse

    Street, R.; Woolery, E.W.; Wang, Z.; Harris, J.B.

    2001-01-01

    Local soil conditions have a profound influence on the characteristics of ground shaking during an earthquake. Exceptionally deep soil deposits, on the order of 100-1000 m deep, are found in the Upper Mississippi Embayment of the central United States. Shear waves (SH) from earthquakes in the New Madrid seismic zone are expected to be strongly affected by the sharp impedance contrasts at the bedrock/sediment interface, attenuation of seismic waves in the soil column, and the SH-wave velocities of the more poorly consolidated near-surface (???50 m) soils. SH-wave velocities of the near-surface soils at nearly 400 sites in the Upper Mississippi Embayment were determined using conventional seismic SH-wave refraction and reflection techniques. Based on the average SH-wave velocities of the upper 30 m of the soils, sites in the Mississippi River floodplain portion of the study area are predominantly classified as Site Class D (180-360 m/s) in accordance with the 1997 NEHRP provisions. Sites away from the active floodplains in western Kentucky and western Tennessee, the SH-wave velocities of the upper 30 m of soils typically ranged from mid-200 to mid-300 m/s. Several sites in western Kentucky had averaged SH-wave velocities greater than 360 m/s, thereby qualifying them as Site Class C (360-760 m/s) in accordance with the 1997 NEHRP provisions. One dimensional site effects, including amplification and dynamic site period, were calculated for a representative suite of sites across the Upper Mississippi Embayment at latitude ?? 38.5??. Although seismic attenuation is greater in the Mississippi River floodplain (i.e. thicker, lower velocity material), the site effects tend to be greater than in the uplands of western Tennessee because of larger impedance contrasts within the near-surface soils. ?? 2001 Elsevier Science B.V. All rights reserved.

  18. Pleistocene variability of Antarctic Ice Sheet extent in the Ross Embayment

    NASA Astrophysics Data System (ADS)

    McKay, Robert; Naish, Tim; Powell, Ross; Barrett, Peter; Scherer, Reed; Talarico, Franco; Kyle, Philip; Monien, Donata; Kuhn, Gerhard; Jackolski, Chris; Williams, Trevor

    2012-02-01

    Cores acquired by the ANDRILL McMurdo Ice Shelf Project (AND-1B) provide the basis for a new sedimentation model for glacimarine depositional sequences that reflect cyclic glacial-interglacial fluctuations of a marine-based ice sheet in the western Ross Embayment over the past 2.0 Ma. Notwithstanding periodic erosion during advances of the ice sheet, uncertainties inherent to the sedimentological interpretation, and a limited number of chronological datums, it is clear that subglacial to grounding-zone sedimentation was dominant at the AND-1B site during the Late Pleistocene with interglacials being represented only by thin intervals of ice-shelf sediment. Each sequence is characterised by subglacial, massive diamictite that pass upwards into glacimarine diamictites and mudstones. This provides the first direct evidence that the marine-based Antarctic Ice Sheet has oscillated between a grounded and floating state at least 7 times in the Ross Embayment over the last 780ka, implying a Milankovitch orbital influence. An unconformity in AND-1B, that spans most (˜200 kyr) of the Mid-Pleistocene Transition is inferred to represent widespread expansion of a marine-based ice sheet in the Ross Embayment at 0.8 Ma. Prior to 1.0 Ma, interglacial periods are characterised by open-water conditions at the drill site with high abundances of volcanoclastic deposits and occasional diatomaceous sediments. These may have responded to precession (˜20-kyr) or obliquity (˜40-kyr) orbital control. The occurrence of 6.7 m of phonolitic glass reworked from Mt Erebus in interglacial deposits beneath Last Glacial Maximum till requires open ocean or ice shelf conditions in the western Ross Sea around the drill site within the past 250 ka and implies a Ross Ice Shelf similar to or less extensive than today during Marine Isotope Stage 7 or 5.

  19. Eulerian and Lagrangian Measurements of Water Flow and Residence Time in a Fringing Coral Reef Embayment

    NASA Astrophysics Data System (ADS)

    Storlazzi, C. D.; Messina, A. M.; Cheriton, O. M.; Biggs, T. W.

    2014-12-01

    Hydrodynamic processes on coral reefs are important for nutrient cycling, larval dispersal, temperature variability, and understanding the impacts of terrestrial sediment, nutrients, and contaminants from adjacent impaired watersheds on coral reef ecosystems. Our goal was to understand the spatial and temporal variability in flow velocities and the associated residence time of water in the fringing coral reef flat-lined embayment of Faga'alu, on the island of Tutuila in American Samoa. To accomplish this, data from three bottom-mounted acoustic current profilers and 102 individual Lagrangian ocean surface current drifter deployments (5 drifters x 21 deployments) were combined with meteorologic data and numerical wave model results. These data and model results, collected over nine days, made it possible to evaluate the relative contribution of tidal, wind, and wave forcing on the flow patterns. The high number of drifter deployments made it possible for the velocity data to be binned into 100 m x 100 m grid cells and the resulting residence times computed for the different sets of forcing conditions. Cumulative progressive vectors calculated from the acoustic current profilers closely matched the tracks from concurrently deployed surface current drifters, showing the applicability of this hybrid Lagrangian-Eulerian measurement scheme to understand flow patterns in this geomorphically complex embayment. The bay-wide man current speeds (residence times) varied from 1-37 cm/s (2.78-0.08 hr), 1-36 cm/s (2.78-0.08 hr), and 5-64 cm/s (0.56-0.04 hr) under tidal, wind, and wave forcing, respectively; the highest speeds (shortest residence times) were measured on the outer reef flat closest to where waves were breaking on the reef crest and were slowest (longest) over the inner reef flat close to shore and deep in the embayment.

  20. Attributes and origins of ancient submarine slides and filled embayments: Examples from the Gulf Coast basin

    SciTech Connect

    Morton, R.A. )

    1993-06-01

    Large submarine slides and associated shelf margin embayments represent an intermediate member in the continuum of unstable shelf margin features. On seismic profiles, they may resemble submarine canyons, but are different in their size, morphology, origin, and hydrocarbon exploration potential. Two large Neogene submarine slides, located in the northwestern Gulf Coast Basin, formed on the upper slope and flanks of prominent shelf-margin deltas. The basal detachment surface of each slide is a structural discontinuity that may be misinterpreted as an erosional unconformity and misidentified as a stratigraphic boundary separating depositional sequences. Regional stratigraphic correlations indicate that both slides were initiated after the continental platform was flooded. The condensed sections deposited during the rise in relative sea level contain the basal detachment surfaces. The relationships between the slides and sea level fluctuations are uncertain. The shelf-margin embayments created by the slides apparently were partly excavated during periods of lowered relative sea level and were filled during sea level rise and highstand. Eventually the preslide morphology of the shelf margin was restored by coalsced prograding deltas. Submarine slides exhibit landward dipping, wavy, mounded, and chaotic seismic reflection that are manifestations of slump blocks and other mass transport material. Composition of these internally derived slide deposits depends on th composition of the pre-existing shelf margin. Embayment fill above the slide consists mostly of externally derived mudstones and sandstones deposited by various disorganized slope processes, as well as more organized submarine channel-level systems. Thickest slope sandstones, which are potential hydrocarbon reservoirs, commonly occur above the basal slide mudstones where seismic reflections change from chaotic patterns to overlying wavy or subhorizontal reflections. 46 refs., 10 figs., 1 tab.

  1. Developing a Skilled and Educated Workforce through Regional Planning. Status Report of Projects Sponsored by the Texas Department of Commerce, the Texas Higher Education Coordinating Board, and the Texas Education Agency.

    ERIC Educational Resources Information Center

    Texas Education Agency, Austin.

    As a result of a call by Texas agencies for demonstration programs in regional planning to assist economic development by educating the work force, three models were funded in December 1987, with plans to continue operating through June 30, 1989. One of the projects is being conducted by the Upper Rio Grande Private Industry Council in El Paso for…

  2. Attributes and origins of ancient submarine slides and filled embayments: examples from the Gulf Coast basin

    USGS Publications Warehouse

    Morton, Robert

    1993-01-01

    Submarine slides exhibit landward-dipping, wavy, mounded, and chaotic seismic reflections that are manifestations of slump blocks and other mass transport material. Composition of these internally derived slide deposits depends on the composition of the preexisting shelf margin. Embayment fill above the slide consists mostly of externally derived mudstones and sandstones deposited by various disorganized slope processes, as well as more organized submarine channel-levee systems. Thickest slope sandstones, which are potential hydrocarbon reservoirs, commonly occur above the basal slide mudstones where seismic reflections change from chaotic patterns to overlying wavy or subhorizontal reflections.

  3. The Impact of Sewage Discharge in a Marine Embayment: A Stable Isotope Reconnaissance

    NASA Astrophysics Data System (ADS)

    Waldron, S.; Tatner, P.; Jack, I.; Arnott, C.

    2001-01-01

    Stable isotope analyses, δ 13C and δ 15N, of sewage tolerant benthic invertebrates seaward of a sewage effluent discharged in a marine embayment, the Firth of Forth, East Scotland, suggest that the polychaete worm Nereis virens is a suitable species for identifying biological assimilation of sewage derived organic matter. The sewage isotopic signal is not strongly recorded in the sediment due to the combined action of tidal movement, wind-induced wave action and benthic invertebrate grazing of particulate matter on the sea-bed. δ 13C of the plankton is significantly different from the effluent, but δ 15N is not which precludes its use as a trace.

  4. How does a tidal embayment morphodynamically react on sea level rise?

    NASA Astrophysics Data System (ADS)

    van der Wegen, Mick

    2010-05-01

    Conditions for (assumed) equilibrium in tidal embayments have been studied extensively in the past years with morphodynamic 1D models (Van Dongeren and De Vriend, 1994; Schuttelaars and de Swart, 1996, 2000; Lanzoni and Seminara, 2002) and 2D models (Hibma et al. [2003], Van der Wegen and Roelvink [2008]) Van der Wegen et al 2008). The current research addresses the impact of sea level rise on tidal embayments. Although effects of sea level rise may only become apparent after decades, the character of the embayment can change considerably. Examples are the (dis)appearance or re-allocation of intertidal flats, increased tidal resonance, shift from sediment export to import, deepening of channel area and other related (ecological) parameters. The research applies a 2D morphodynamic model (Delft3D) in an idealized environment. The model is based on the 2 D shallow water equations, the Engelund -Hansen transport formula and includes bed slope effects, drying and flooding procedures and an advanced morphodynamic update scheme (Roelvink 2006). The initial condition of the bathymetry is generated by 3000 years of morphodynamic calculations in a 80 km long and 2.5 km wide rectangular tidal embayment under constant M2 tidal forcing conditions (Van der Wegen and Roelvink [2008]). After this period sea level rise gradually developing towards a rate of 0.4 m/century is added to the boundary conditions. Model results describe development towards less intertidal area and a transition from an exporting system to a importing system. Model results are evaluated in terms of M2, M4 and M6 tidal constituents as well as against Vs/Vc (shoal volume over channel volume) versus a/h (amplitude over water depth) relationship as proposed by Friedrichs and Aubrey (1988). Although the model describes morphodynamic development in a strongly idealized environment the results can provide an excellent tool to systematically study the impact of sea level rise in tidal embayments as well as the time

  5. Lower Rio Grande Valley transboundary air pollution project (TAPP). Project report 1996--1997

    SciTech Connect

    Mukerjee, S.; Shadwick, D.S.; Dean, K.E.; Carmichael, L.Y.; Bowser, J.J.

    1999-04-01

    The Lower Rio Grande Valley Transboundary Air Pollution Project (TAPP) was a US-Mexico Border XXI project to find out if air pollutants were moving across the border from Mexico into the Lower Rio Grande Valley of Texas and to see what levels of air pollutants were present. Ambient measurements and meteorology were collected data for a year (March 1996-March 1997) at three fixed sites in and near Brownsville, Texas very close to the US-Mexico border on a continuous and 24-h internal basis. Overall levels of air pollution were similar to or lower than other areas in Texas and elsewhere. Based on wind sector analyses, transport of air pollution across the border did not appear to adversely impact air quality on the US side of the Valley. Southeasterly winds from the Gulf of Mexico were largely responsible for the clean air conditions.

  6. Columbia Glacier, Alaska recent ice loss and its relationship to seasonal terminal embayments, thinning and glacial flow

    USGS Publications Warehouse

    Sikonia, W.G.; Post, Austin

    1980-01-01

    In 1974 the U.S. Geological Survey began an intensive investigation of the stability of Columbia Glacier, a calving tidewater galcier terminating in Columbia Bay, near Valdez, Alaska. Aerial photographs taken in 1957 and a sequence of photographs taken at about 2-month intervals since 1976, when analyzed photogrammetrically, provided detailed data on changes in Columbia Glacier 's thickness, flow rate, and terminal position. Annual embayments in the glacier 's terminus form during the summer-autumn season in most years; the size of embayments appears to be related to (1) the thickness of the glacier, and (2) the position and nature of subglacial freshwater discharge. Embayments have apparently increased in size in recent years; the largest embayments yet observed formed in 1975, 1976, 1977, and 1978. From April 1, 1977, to April 1, 1978, the total volume of ice calved was about 1.0 cubic kilometer. By January 1979 the glacier front had retreated from Heather Island. Glacier flow varies seasonally and synchronously in the lower 17 kilometers of the glacier; large accelerations occur near the terminus in response to embayment formation. Daily speed within 5 kilometers of the terminus increased from about 1.9 meters per day between 1963 and 1968 to about 2.7 meters per day between 1977 and 1978. In the lowest 15 kilometers, the glacier surface was lowered about 9 meters between 1957 and 1974, and about 13 meters between 1974 and 1978. Columbia Glacier is being reduced in mass due, in part, to recent losses caused by large embayments forming annually. If such reduction continues it will result in a drastic retreat. (USGS)

  7. Paleocene to Middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy

    USGS Publications Warehouse

    Poag, C.W.; Commeau, J.A.

    1995-01-01

    The Paleocene to Middle Miocene sedimentary fill of the southwestern Salisbury Embayment contains a fragmental depositional record, interrupted by numerous local diastems and regional unconformities. Using planktic foraminiferal biostratigraphy, 15 unconformity-bounded depositional units have been identified, assigned to six formations and seven alloformations previously recognized in the embayment. The units correlate with second- and third-order sequences of the Exxon sequence stratigraphy model, and include transgressive and highstand systems tracts. Alloformation, formation, and sequence boundaries are marked by abrupt, scoured, burrowed, erosional surfaces, which display lag deposits, biostratigraphic gaps, and intense reworking of microfossils above and below the boundaries. -from Authors

  8. Spatial and temporal trends in summertime climate and water quality indicators in the coastal embayments of Buzzards Bay, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rheuban, J. E.; Williamson, S. C.; Costa, J. E.; Glover, D. M.; Jakuba, R. W.; McCorkle, D. C.; Neill, C.; Williams, T.; Doney, S. C.

    2015-08-01

    Degradation of coastal ecosystems by eutrophication is largely defined by nitrogen loading from land via surface and groundwater flows. However, indicators of water quality are highly variable due to a myriad of other drivers, including temperature and precipitation. To evaluate these drivers, we examined spatial and temporal trends in a 22 year record of summer water quality data from 122 stations in 17 embayments within Buzzards Bay, MA (USA), collected through a citizen science monitoring program managed by Buzzards Bay Coalition. To identify spatial patterns across Buzzards Bay's embayments, we used a principle component and factor analysis and found that rotated factor loadings indicated little correlation between inorganic nutrients and organic matter and chlorophyll a (Chl a) concentration. Factor scores showed that embayment geomorphology in addition to nutrient loading was a strong driver of water quality, where embayments with surface water inputs showed larger biological impacts than embayments dominated by groundwater influx. A linear regression analysis of annual summertime water quality indicators over time revealed that from 1992 to 2013, most embayments (15 of 17) exhibited an increase in temperature (mean rate of 0.082 ± 0.025 (SD) °C yr-1) and Chl a (mean rate of 0.0171 ± 0.0088 log10 (Chl a; mg m-3) yr-1, equivalent to a 4.0 % increase per year). However, only 7 embayments exhibited an increase in total nitrogen (TN) concentration (mean rate 0.32 ± 0.47 (SD) μM yr-1). Average summertime log10 (TN) and log10 (Chl a) were correlated with an indication that yield of Chl a per unit total nitrogen increased with time suggesting the estuarine response to TN may have changed because of other stressors such as warming, altered precipitation patterns, or changing light levels. These findings affirm that nitrogen loading and physical aspects of embayments are essential in explaining observed ecosystem response. However, climate-related stressors may

  9. Spatial and temporal trends in summertime climate and water quality indicators in the coastal embayments of Buzzards Bay, Massachusetts

    NASA Astrophysics Data System (ADS)

    Rheuban, J. E.; Williamson, S.; Costa, J. E.; Glover, D. M.; Jakuba, R. W.; McCorkle, D. C.; Neill, C.; Williams, T.; Doney, S. C.

    2016-01-01

    Degradation of coastal ecosystems by eutrophication is largely defined by nitrogen loading from land via surface water and groundwater flows. However, indicators of water quality are highly variable due to a myriad of other drivers, including temperature and precipitation. To evaluate these drivers, we examined spatial and temporal trends in a 22-year record of summer water quality data from 122 stations in 17 embayments within Buzzards Bay, MA (USA), collected through a citizen science monitoring program managed by Buzzards Bay Coalition. To identify spatial patterns across Buzzards Bay's embayments, we used a principle component and factor analysis and found that rotated factor loadings indicated little correlation between inorganic nutrients and organic matter or chlorophyll a (Chl a) concentration. Factor scores showed that embayment geomorphology in addition to nutrient loading was a strong driver of water quality, where embayments with surface water inputs showed larger biological impacts than embayments dominated by groundwater influx. A linear regression analysis of annual summertime water quality indicators over time revealed that from 1992 to 2013, most embayments (15 of 17) exhibited an increase in temperature (mean rate of 0.082 ± 0.025 (SD) °C yr-1) and Chl a (mean rate of 0.0171 ± 0.0088 log10 (Chl a; mg m-3) yr-1, equivalent to a 4.0 % increase per year). However, only seven embayments exhibited an increase in total nitrogen (TN) concentration (mean rate 0.32 ± 0.47 (SD) µM yr-1). Average summertime log10(TN) and log10(Chl a) were correlated with an indication that the yield of Chl a per unit total nitrogen increased with time suggesting the estuarine response to TN may have changed because of other stressors such as warming, altered precipitation patterns, or changing light levels. These findings affirm that nitrogen loading and physical aspects of embayments are essential in explaining the

  10. Water-quality trends in the Rio Grande/Rio Bravo Basin using sediment cores from reservoirs

    USGS Publications Warehouse

    Van Metre, Peter C.; Mahler, B.J.; Callender, Edward C.

    1997-01-01

    In 1991, the U.S. Geological Survey (USGS) began full implementation of the National Water-Quality Assessment (NAWQA) Program (Leahy and others, 1990). Also in 1991, the State of Texas established the Clean Rivers Program (CRP) administered by the Texas Natural Resource Conservation Commission (TNRCC). The coring study reported here was a collaborative effort between the NAWQA Program and the CRP Rio Grande Border Environmental Assessment Team, with additional funding support from the El Paso County Water Improvement District No. 1.

  11. Chemical Contamination of the Lower Rio Grande near Laredo, TX

    NASA Astrophysics Data System (ADS)

    Flores, B.; Ren, J.; Krishnamurthy, S.; Belzer, W.

    2006-12-01

    The Rio Grande River stretches over 2000 miles from the southern Rocky Mountains in Colorado to the tip of Texas where the Rio Grande meets the Gulf of Mexico. It is the natural boundary between U.S. and Mexico from El Paso, TX, to Brownsville, TX. The communities along the border heavily rely upon the Rio Grande as a primary source of water for consumption, agricultural uses, supporting wildlife and recreation. For many years the Rio Grande has been polluted with municipal, industrial, agricultural and farming contaminants from both sides of the border. This pollution has led to the extinction or reduction of certain wildlife species as well as affecting the health of the residences along the border. Even though great strides have been made in monitoring the Rio Grande, there has been a lack of intense monitoring data collection for pollutants such as pesticides. Three sampling sites including Manadas Creek, the Rio Grande River at International Bridge I, and USGS monitoring site 08459200 off of Highway 83 were chosen. The water quality parameters focused include temperature, pH, conductivity, dissolve oxygen (DO), salinity, total dissolved solids, nutrients, metals and pesticides. Preliminary results have shown elevated concentration of total phosphorus and ortho-phosphorus in the Manadas Creek site. Organochlorinated pesticides such as heptachlor and 4, 4 DDE were detected at various concentrations at all sites and endrin aldehyde was found at Manadas Creek site. This research has provided more information on the current chemical contamination level of the Rio Grande in the Laredo area.

  12. Present-day Halimeda carbonate sediments in temperate mediterranean embayments: Fornells, Balearic Islands

    NASA Astrophysics Data System (ADS)

    Fornos, J. J.; Forteza, V.; Jaume, C.; Martinez-Taberner, A.

    1992-01-01

    Fornells Bay is an enclosed embayment located in the north of the Balearic Platform in the Western Mediterranean. It displays bioelastic sedimentation with strong terrigenous influences. The plant communities responsible for the carbonate sediment input are the seagrasses Posidonia oceanica and Cymodocea nodosa, and red and green algae, the most important of which is Halimeda tuna. The distribution of the latter is clearly related to bathymetry and it forms the principal bioclastic component ( > 40%) in shallow sediments (0-25 m). Red algae are found below 30 m with a characteristic branching coralline algae sea floor. Organic matter in the finest-grained facies attains 6.59%. The bay exhibits a hydrodynamic gradient from low in the interior where there is a terrigenous influence to high in the outer open marine sectors. The presence of Halimeda-rich carbonates and fine-grained terrigenous sediments within Balearic embayments provides an example of Chloralgal facies in a region where Foramol would have been expected. The system described provides new data for the interpretation of fossil temperate-water carbonates.

  13. A joint local and teleseismic tomography study of the Mississippi Embayment and New Madrid Seismic Zone

    NASA Astrophysics Data System (ADS)

    Nyamwandha, Cecilia A.; Powell, Christine A.; Langston, Charles A.

    2016-05-01

    Detailed, upper mantle P and S wave velocity (Vp and Vs) models are developed for the northern Mississippi Embayment (ME), a major physiographic feature in the Central United States (U.S.) and the location of the active New Madrid Seismic Zone (NMSZ). This study incorporates local earthquake and teleseismic data from the New Madrid Seismic Network, the Earthscope Transportable Array, and the FlexArray Northern Embayment Lithospheric Experiment stations. The Vp and Vs solutions contain anomalies with similar magnitudes and spatial distributions. High velocities are present in the lower crust beneath the NMSZ. A pronounced low-velocity anomaly of ~ -3%--5% is imaged at depths of 100-250 km. High-velocity anomalies of ~ +3%-+4% are observed at depths of 80-160 km and are located along the sides and top of the low-velocity anomaly. The low-velocity anomaly is attributed to the presence of hot fluids upwelling from a flat slab segment stalled in the transition zone below the Central U.S.; the thinned and weakened ME lithosphere, still at slightly higher temperatures from the passage of the Bermuda hotspot in mid-Cretaceous, provides an optimal pathway for the ascent of the fluids. The observed high-velocity anomalies are attributed to the presence of mafic rocks emplaced beneath the ME during initial rifting in the early Paleozoic and to remnants of the depleted, lower portion of the lithosphere.

  14. Microphytobenthos potential productivity estimated in three tidal embayments of the San Francisco Bay system

    USGS Publications Warehouse

    Guarini, Jean-Marc; Cloern, James E.; Edmunds, Jody L.; Gros, Philippe

    2002-01-01

    In this paper we describe a three-step procedure to infer the spatial heterogeneity in microphytobenthos primary productivity at the scale of tidal estuaries and embayments. The first step involves local measurement of the carbon assimilation rate of benthic microalgae to determine the parameters of the photosynthesis-irradiance (P-E) curves (using non-linear optimization methods). In the next step, a resampling technique is used to rebuild pseudo-sampling distributions of the local productivity estimates; these provide error estimates for determining the significance level of differences between sites. The third step combines the previous results with deterministic models of tidal elevation and solar irradiance to compute mean and variance of the daily areal primary productivity over an entire intertidal mudflat area within each embayment. This scheme was applied on three different intertidal mudflat regions of the San Francisco Bay estuary during autumn 1998. Microphytobenthos productivity exhibits strong (ca. 3-fold) significant differences among the major sub-basins of San Francisco Bay. This spatial heterogeneity is attributed to two main causes: significant differences in the photosynthetic competence (P-E parameters) of the microphytobenthos in the different sub-basins, and spatial differences in the phase shifts between the tidal and solar cycles controlling the exposure of intertidal areas to sunlight. The procedure is general and can be used in other estuaries to assess the magnitude and patterns of spatial variability of microphytobenthos productivity at the level of the ecosystems.

  15. Microphytobenthic potential productivity estimated in three tidal embayments of the San Francisco Bay: A comparative study

    USGS Publications Warehouse

    Guarini, J.-M.; Cloern, James E.; Edmunds, J.

    2002-01-01

    In this paper we describe a three-step procedure to infer the spatial heterogeneity in microphytobenthos primary productivity at the scale of tidal estuaries and embayments. The first step involves local measurement of the carbon assimilation rate of benthic microalgae to determine the parameters of the photosynthesis-irradiance (P-E) curves (using non-linear optimization methods). In the next step, a resampling technique is used to rebuild pseudo-sampling distributions of the local productivity estimates; these provide error estimates for determining the significance level of differences between sites. The third step combines the previous results with deterministic models of tidal elevation and solar irradiance to compute mean and variance of the daily areal primary productivity over an entire intertidal mudflat area within each embayment. This scheme was applied on three different intertidal mudflat regions of the San Francisco Bay estuary during autumn 1998. Microphytobenthos productivity exhibits strong (ca. 3-fold) significant differences among the major sub-basins of San Francisco Bay. This spatial heterogeneity is attributed to two main causes: significant differences in the photosynthetic competence (P-E parameters) of the microphytobenthos in the different sub-basins, and spatial differences in the phase shifts between the tidal and solar cycles controlling the exposure of intertidal areas to sunlight. The procedure is general and can be used in other estuaries to assess the magnitude and patterns of spatial variability of microphytobenthos productivity at the level of the ecosystems.

  16. Sylvatic trichinellosis in Texas.

    PubMed

    Pence, D B; La Rosa, G; Mancini Barbieri, F; Amati, M; Casulli, A; Pozio, E

    2001-06-01

    There are no published reports of domestic or sylvatic trichinellosis in Texas. The aim of the present survey was to determine the presence of Trichinella species in selected representative species of potential wildlife reservoirs in southern Texas. In 1998-99, tongues of 211 wild mammals were collected in southern Texas: 154 coyotes (Canis latrans), three bobcats (Lynx rufus), 32 racoons (Procyon lotor), 13 opossum (Didelphis marsupialis), four ocelots (Leopardus pardalis) and five wild boars (Sus scrofa). Presence of Trichinella sp. larvae was investigated by artificial digestion and larvae of positive samples were identified at the species level by a multiple-polymerase chain reaction analysis. Nine (5.8%) coyotes had trichinellosis; in the muscles of seven of these coyotes, the larvae were identified as Trichinella murrelli. This is the first report of sylvatic trichinellosis in Texas. PMID:11484391

  17. Petrologic model of the northern Mississippi Embayment based on satellite magnetic and ground-based geophysical data

    NASA Technical Reports Server (NTRS)

    Thomas, H. H.

    1984-01-01

    A petrologic model of the northern Mississippi Embayment, derived from gravity, seismic and rift data, is evaluated by converting the model to a magnetization model which is compared with satellite magnetic anomaly models. A magnetization contrast of approximately -0.54 A/m, determined from the petrologic model of the embayment compares favorably to values of -0.62 A/m and -0.45 A/m from a Magsat United States Apparent Magnetization Contrast Map and a published POGO magnetization contrast model, respectively. The petrologic model suggests that the magnetic anomaly low associated with the Mississippi Embayment may be largely due to the intrusion under non-oxidizing conditions of low Curie temperature gabbroic material at the base of the crust of the embayment. Near-surface mafic plutons, bordering the Mississippi Valley Graben, appear from aeromagnetic data to have higher magnetizations than the deeper gabbroic material; however, it is impossible to ascertain if this is due to compositional differences or similar material at shallower (lower temperature) depths. These results indicate that variations in the Curie temperatures of intrusions accompanying rifting may account for a large part of the wide range of magnetic anomalies associated with presently inactive rifts with normal heat flow.

  18. Imaging of shallow crustal structure in upper Mississippi Embayment using microearthquake waveforms

    NASA Astrophysics Data System (ADS)

    Chiu, S. C.; Chiu, J.; Langston, C. A.; Wang, Z.; Woolery, E. W.; Withers, M. M.

    2012-12-01

    Imagings of local microearthquake displacement seismograms from P- and S-wave coda and Sp converting wave recorded on broadband stations, CUKY, HICK, PARM, PENM, PEBM, and GNAR are used to resolve P- and S-wave velocity structure for the unconsolidated sedimentary layer in upper Mississippi Embayment. Incorporated to logging data from the newly operative deep borehole CUSSO (Central United States Seismic Observatory), P-wave velocity of 2.0 km/s and S-wave velocity of 0.6 km/s can be determined to represent the average velocity structure of the entire unconsolidated sediments column in the region of southwestern Kentucky within the Mississippi embayment basin. This leads to Vp/Vs 3.3333 and Poisson ratio 0.4505 correspondently. These results are consistent to the observations of the vertical-component P and horizontal-component S waveform recorded by receivers resided at both the top and the bottom of the CUSSO vertical array. The results also agree to the Sp-to-S differential traveltime shown on the vertical- component seismogram and are similar to previous studies; however, S-wave velocity is slightly lower than that obtained in the west part of embayment and is much higher than the direct measurements from the CUSSO. It is suggested that accuracy of the logging data needs be re-evaluated. A reflector in the deeper Paleozoic sedimentary rocks also correlates well to the Bonneterre Formation shown in the stratigraphy of the nearby well logs; yet, the low-velocity Elvins interface does not appear clearly among imaging profiles at CUKY and HICK or this layer is too thin to be resolved. The low velocity layer is also not apparent beneath PARM probably due to the existence of Bloomfield pluton. Five major reflectors within unconsolidated sediments that are identified by imaging these waves agree to the result obtained from the reflection/refraction experiment conducted under a joint USGS project between the University of Memphis and the University of Kentucky. This

  19. Palaeo-ice stream pathways in the easternmost Amundsen Sea Embayment, West Antarctica

    NASA Astrophysics Data System (ADS)

    Klages, Johann P.; Kuhn, Gerhard; Graham, Alastair G. C.; Smith, James A.; Hillenbrand, Claus-Dieter; Nitsche, Frank O.; Larter, Rob D.; Gohl, Karsten

    2015-04-01

    Multibeam swath bathymetry datasets collected over the past two decades have been compiled to identify palaeo-ice stream pathways in the easternmost Amundsen Sea Embayment. We mapped 3010 glacial landforms to reconstruct palaeo-ice flow in the ~250 km-long Abbot Glacial Trough that was occupied by a large palaeo-ice stream, fed by two tributaries (Cosgrove and Abbot) that reached the continental shelf edge during the last maximum ice-sheet advance. The mapping has enabled a clear differentiation between glacial landforms interpreted as indicative of wet- (e.g. mega-scale glacial lineations) and cold-based ice (e.g. hill-hole pairs) during the last glaciation of the continental shelf. Both the regions of fast palaeo-ice flow within the palaeo-ice stream troughs, and the regions of slow palaeo-ice flow on adjacent seafloor highs (referred to as inter-ice stream ridges) additionally record glacial landforms such as grounding-zone wedges and recessional moraines that indicate grounding line stillstands of the ice sheet during the last deglaciation from the shelf. As the palaeo-ice stream flowed along a trough with variable geometry and variable subglacial substrate, it appears that trough sections characterized by constrictions and outcropping hard substrate that changes the bed gradient, led the pace of grounding-line retreat to slow and subsequently pause, resulting in the deposition of grounding-zone wedges. The stepped retreat recorded within the Abbot Glacial Trough corresponds well to post-glacial stepped retreat interpreted for the neighbouring Pine Island-Thwaites Palaeo-Ice Stream trough, thus suggesting a uniform pattern of episodic retreat across the eastern Amundsen Sea Embayment. The correlation of episodic retreat features with geological boundaries further emphasises the significance of subglacial geology in steering ice stream flow. Our new geomorphological map of the easternmost Amundsen Sea Embayment resolves the pathways of palaeo-ice streams that

  20. Ascent Rates from Melt Embayments: Insights into the Eruption Dynamics of Arc Volcanoes

    NASA Astrophysics Data System (ADS)

    Ruprecht, P.; Lloyd, A. S.; Hauri, E.; Rose, W. I.; Gonnermann, H. M.; Plank, T. A.

    2014-12-01

    A significant fraction of the magma that is added from the mantle to the subvolcanic plumbing system ultimately erupts at the surface. The initial volatile content of the magmas as well as the interplay between volatile loss and magma ascent plays a significant role in determining the eruption style (effusive versus explosive) as well as the magnitude of the eruption. The October 17, 1974 sub-Plinian eruption of Volcán de Fuego represents a particularly well-characterized system in terms of volatile content and magma chemistry to investigate the relation between initial water content of the magmas and the ascent rate. By modeling volatile element distribution in melt embayments through diffusion and degassing during ascent we can estimate magma ascent from the storage region in the crust to the surface. The novel aspect is the measurement of concentration gradients multiple volatile elements (in particular CO2, H2O, S) at fine-scale (5-10 μm) using the NanoSIMS. The wide range in diffusivity and solubility of these different volatiles provides multiple constraints on ascent timescales over a range of depths. H2O, CO2, and S all decrease toward the embayment outlet bubble documenting the loss of H2O and CO2 compared to an extensive melt inclusion suite from the same day of the eruption. The data is best described by a two-stage model. At high pressure (>145 MPa) decompression is slow (0.05- 0.3 MPa/s) and CO2 is bled off predominantly. At shallow levels decompression accelerates to 0.3-0.5 MPa/s at the point of H2O exsolution, which strongly affects the buoyancy of the ascending magma. The magma ascent rates presented are among the first for explosive basaltic eruptions and demonstrate the potential of the embayment method for quantifying magmatic timescales associated with eruptions of different vigor. [1] Lloyd et al. (2014) JVGR, http://dx.doi.org/10.1016/j.jvolgeores.2014.06.002

  1. Detection of Rhynchophorus palmarum (Coleoptera: Curculionidae) and identification of associated nematodes in south Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports a survey conducted to find the South American palm weevil Rhynchophorus palmarum (L.) and the red palm weevil R. ferrugineus (Olivier) (Coleoptera: Curculionidae), two invasive species of palm trees. The study was performed in the Rio Grande Valley of south Texas and near the bor...

  2. Mexico, New Mexico and Texas as seen from the Apollo 6 unmanned spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Mexico, New Mexico and Texas are photographed from the Apollo 6 (Spacecraft 020/Saturn 502) unmanned space mission during its 2nd orbit of the Earth. Seen in this photograph are Deming, Palomas, Las Cruces, El Paso, Florida Mountains, East and West Portrillo Mountains, San Andres Mountains, Franklin Mountains, and Juarez Mountains and the Rio Grande River.

  3. Isaria poprawskii sp. nov. (Hypocreales: Cordycipitacae), a new entomopathogenic fungus from Texas affecting sweet potato whitefly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isaria poprawskii is described as a new entomopathogenic species similar to Isaria javanica (=Paecilomyces javanicus). It was discovered ont he sweet potato whitefly, Bemisia tabaci biotype B in the Lower Rio Grande Valley of Texas (LRGV), USA. Morphological and DNA examinations indicated the dist...

  4. Risk-based residential HLB/ACP survey for California, Texas and Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent discoveries of HLB in the Los Angeles Basin and the Rio Grande Valley of Texas underscore the imminent danger of HLB spread in these two States and the urgent need for highly sensitive survey methods for early detection of new residential infections of HLB combined with rapid intervention...

  5. Water quality monitoring report for the White Oak Creek Embayment. Environmental Restoration Program

    SciTech Connect

    Ford, C.J.; Wefer, M.T.

    1993-01-01

    Water quality monitoring activities that focused on the detection of resuspended sediments in the Clinch River were conducted in conjunction with the White Oak Creek Embayment (WOCE) time-critical Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to construct a sediment-retention structure at the mouth of White Oak Creek (WOC). Samples were collected by use of a 24-h composite sampler and through real-time water grab sampling of sediment plumes generated by the construction activities. Sampling stations were established both at the WOC mouth, immediately adjacent to the construction site, and at K-1513, the Oak Ridge K-25 Site drinking water intake approximately 9.6 km downstream in the Clinch River. Results are described.

  6. Moving sands along a headland-embayed beach system (Algarve, Southern Portugal)

    NASA Astrophysics Data System (ADS)

    Oliveira, Sónia; Horta, João; Nascimento, Ana; Gomes, Ana; Veiga-Pires, Cristina; Moura, Delminda

    2015-04-01

    Resilience of embayed and pocket beaches located at the southernmost coast of Portugal is currently a major question to coastal management of this region. In fact, several among those beaches have been artificially fed aiming to increase the width of the beach allowing people to maintain a safe distance to the unstable rocky cliffs. The sand is dredged from the offshore (ca. 2 miles from the shoreline) representing high costs for the Portuguese government. For how long will the artificial feeding solve the problem? Which beaches are worth being nourished taking into account the morphosedimentary processes? The present work is the result of a field experiment aiming to study the efficiency of the alongshore sedimentary transport between successive embayed beaches. The experiment was performed in the very indented rocky coast of the Algarve region (Southern Portugal) and comprised two field campaigns, both in 2014, during spring tides in March and November. The Algarve coast experiences a semi-diurnal meso-tidal regime ranging from 1.3 m during neap tides to 3.5 m at spring tides and the waves approach from WSW (232°) during 72% of observations along the year, almost normal to the study area shoreline. The wave and current characteristics (significant height-Hs and Period-T for waves, velocity and direction for currents) were measured during three and six tidal cycles respectively for the first and second campaign, using two pressure transducers and one electromagnetic current meter. We used sand painted with orange fluorescent dye (100 kg in March and 200 kg in November) as tracer to track the movement of the sand along the coast. The marked sand was placed on the beach face of the westernmost beach of the study area during the first low tide of each campaign. Following, hundreds of sediment samples were collected during low tide, through the monitored period, in the nodes of a georeferenced square mesh of 10 x 20 m covering three embayed beaches. Later in the

  7. Ground-water flow analysis of the Mississippi Embayment aquifer system, South-Central United States

    USGS Publications Warehouse

    Arthur, J.K.; Taylor, R.E.

    1998-01-01

    The Mississippi Embayment aquifer system is composed of six regional aquifers covering about 160,000 square miles in parts of Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. The flow analysis presented in this report as part of the Gulf Coast Regional Aquifer-System Analysis study pertains to five aquifers in sediments of the Wilcox and Claiborne groups of Tertiary age. In descending order, the aquifers are (1) the upper Claiborne, (2) the middle Claiborne, (3) the lower Claiborne-upper Wilcox, (4) the middle Wilcox, and (5) the lower Wilcox. The flow analysis of the sixth aquifer in the aquifer system, the Mississippi River valley alluvial aquifer in sediments of Holocene and Pleistocene age, is presented in chapter D of this Professional Paper.

  8. Petrologic model of the northern Mississippi embayment based on satellite magnetic and ground based geophysical data

    NASA Technical Reports Server (NTRS)

    Thomas, H. H.

    1983-01-01

    Magnetization, derived from gravity-seismic data from the northern Mississippi Embayment, is evaluated relative to magnetization values obtained from satellite magnetic data. A magnetization contrast of approximately -0.54 A/m determined from the geophysical model compares favorably to a value of approximately -0.47 A/m from MAGSAT United States Apparent Magnetization contrast map. The negative magnetization contrast, required by the MAGSAT data, is unusual as rift zones with the exception of those which are currently active are associated with positive magnetization. The model presented favors an intrusion of low Curie temperature mafic rock at the base of the crust. Alternate possibilities, a shallow Curie isotherm or remanence in a direction other than that of the current main field, seem less likely as reported regional heat flow values are too low and remanence is attenuated at depth.

  9. Stratigraphic and palaeoenvironmental summary of the south-east Georgia Embayment: a correlation of exploratory wells

    USGS Publications Warehouse

    Poppe, L.J.; Popenoe, P.; Poag, C.W.; Swift, B.A.

    1995-01-01

    A Continental Offshore Stratigraphic Test (COST) well and six exploratory wells have been drilled in the south-east Georgia embayment. The oldest rocks penetrated are weakly metamorphosed Lower Ordovician quartz arenites and Silurian shales and argillites in the Transco 1005-1 well and Upper Devonian argillites in the COST GE-1 well. The Palaeozoic strata are unconformably overlain by interbedded non-marine Jurassic sandstones and shales and marginal marine Lower Cretaceous rocks. Together, these rocks are stratigraphically equivalent to the onshore Fort Pierce and Cotton Valley(?) Formations and rocks of the Lower Cretaceous Comanchean Provincial Series. The Upper Cretaceous part of the section is composed mainly of neritic calcareous shales and shaley limestones stratigraphically equivalent to the primarily marginal marine facies of the onshore Atkinson, Cape Fear and Middendorf Formations and Black Creek Group, and to limestones and shales of the Lawson Limestone and Peedee Formations. Cenozoic strata are also described. -from Authors

  10. Occurrence of invertebrates at 38 stream sites in the Mississippi Embayment study unit, 1996-99

    USGS Publications Warehouse

    Caskey, Brian J.; Justus, B.G.; Zappia, Humbert

    2002-01-01

    A total of 88 invertebrate species and 178 genera representing 59 families, 8 orders, 6 classes, and 3 phyla was identified at 38 stream sites in the Mississippi Embayment Study Unit from 1996 through 1999 as part of the National Water-Quality Assessment Program. Sites were selected based on land use within the drainage basins and the availability of long-term streamflow data. Invertebrates were sampled as part of an overall sampling design to provide information related to the status and trends in water quality in the Mississippi Embayment Study Unit, which includes parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. Invertebrate sampling and processing was conducted using nationally standardized techniques developed for the National Water-Quality Assessment Program. These techniques included both a semi-quantitative method, which targeted habitats where invertebrate diversity is expected to be highest, and a qualitative multihabitat method, which samples all available habitat types possible within a sampling reach. All invertebrate samples were shipped to the USGS National Water-Quality Laboratory (NWQL) where they were processed. Of the 365 taxa identified, 156 were identified with the semi-quantitative method that involved sampling a known quantity of what was expected to be the richest habitat, woody debris. The qualitative method, which involved sampling all available habitats, identified 345 taxa The number of organisms identified in the semi-quantitative samples ranged from 74 to 3,295, whereas the number of taxa identified ranged from 9 to 54. The number of organisms identified in the qualitative samples ranged from 42 to 29,634, whereas the number of taxa ranged from 18 to 81. From all the organisms identified, chironomid taxa were the most frequently identified, and plecopteran taxa were among the least frequently identified.

  11. Reorganization of Strain in Response to Erosional Forcing at Intermediate Scales: Puli Embayment, Western Taiwan

    NASA Astrophysics Data System (ADS)

    Upton, P.; Mueller, K. J.; Koons, P. O.; Powell, L.

    2003-12-01

    The Taiwan orogeny accommodates 82 mm of oblique convergence per year between the Philippine Sea and Eurasian plates and is situated in a region of very high rainfall, resulting in high rates of rock uplift and erosion. Studies in western Taiwan suggest that there is considerable along strike variation in late Quaternary erosion rates and in the modern distribution of strain along the western margin of the orogen. In the Puli Embayment, a 50 km wide, 1500 m deep depression within the Foothills belt, Hsueshan Range and Backbone Ranges of western Taiwan, lower elevation and enhanced exhumation are associated with a broad 50 km wide belt of active shortening hindward of the leading edge of the orogen. Localized high erosion rates have been shown to significantly influence the mechanical behavior of collisional mountain belts on timescales of 1-5 Ma where the wavelength of the erosional signal is on the order of the thickness of the brittle crust. Examples include the Southern Alps of New Zealand and the indentor corners, Nanga Parbat and Namche Bawa, of the Himalaya, where the geometry of the erosional signal is reflected in the topographic and petrological signal of the resultant mountain belt. The coincidence of enhanced exhumation, lower elevation and active deformation suggests that the Puli embayment is accommodating shortening and rock uplift in response to the reduction in mass. If so, it is occurring on shorter temporal and spatial scales than previously documented and may represent the early stages of river-induced thermal thinning leading to the formation of a structure on the scale of an anticlinorium. Western Taiwan provides an ideal setting in which to explore, on a sub-orogen scale, the implications of enhanced exhumation for the beginnings of reorganization of strain within an orogen at higher spatial and temporal frequency.

  12. New Results and Future IPY Investigations in Hektoria Trough, Inner Larsen-B Embayment, Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Brachfeld, S.; Domack, E. W.; Leventer, A.; Willmott, V.; Ishman, S.

    2007-12-01

    We present new results from a sediment core collected in the inner Larsen-B embayment, Antarctic Peninsula. The 2002 break-up of the Larsen-B Ice Shelf enabled access to the termini of glaciers that formerly fed into the ice shelf. United States Antarctic Program cruise LMG05-02 discovered and mapped an 800-m deep glacial trough off Hektoria Glacier at the northern end of the Larsen-B embayment. Sub-bottom profiling reveals the presence of at least 20-m of unconsolidated sediment in the trough, which varies in character between acoustically laminated, and packages with weak, discontinuous reflectors. A 2.5-m kasten core was recovered from the Hektoria trough during cruise LMG05-02. The sediment consists of silty clay with a minor component of very fine sand, and is laminated in the uppermost meter. Downcore magnetic and geochemical parameters were used to investigate the terrigenous sediment supplied to Hektoria Trough. Bulk sediment geochemistry suggests a constant sediment source that is chemically consistent with upper continental crust. Magnetic parameters reveal several intervals in which the magnetic material supplied to the trough varies in abundance and particle size. We observe shifts at approximately 850, 5900, and 7900 14C yr B.P., based on a preliminary age model. Superimposed on these shifts are periodic pulses of coarser material into the trough, which may be related to fluctuations in the location of the grounding line with respect to the core site. Our preliminary age model indicates an average sedimentation rate of 21 cm/kyr, which suggests that the basin fill extends back to perhaps 100,000 yr B.P., a rare archive of the late Pleistocene in an ice proximal site.

  13. Seismic reflection images of shallow faulting, northernmost Mississippi embayment, north of the New Madrid seismic zone

    USGS Publications Warehouse

    McBride, J.H.; Nelson, W.J.

    2001-01-01

    High-resolution seismic reflection surveys document tectonic faults that displace Pleistocene and older strata just beyond the northeast termination of the New Madrid seismic zone, at the northernmost extent of the Mississippi embayment. These faults, which are part of the Fluorspar Area fault complex in southeastern Illinois, are directly in line with the northeast-trending seismic zone. The reflection data were acquired using an elastic weight-drop source recorded to 500 msec by a 48-geophone array (24-fold) with a 10-ft (??3.0m) station interval. Recognizable reflections were recorded to about 200 msec (100-150 m). The effects of multiple reflections, numerous diffractions, low apparent velocity (i.e., steeply dipping) noise, and the relatively low-frequency content of the recorded signal provided challenges for data processing and interpreting subtle fault offsets. Data processing steps that were critical to the detection of faults included residual statics, post-stack migration, deconvolution, and noise-reduction filtering. Seismic migration was crucial for detecting and mitigating complex fault-related diffraction patterns, which produced an apparent 'folding' of reflectors on unmigrated sections. Detected individual offsets of shallow reflectors range from 5 to 10 m for the top of Paleozoic bedrock and younger strata. The migrated sections generally indicate vertical to steeply dipping normal and reverse faults, which in places outline small horsts and/or grabens. Tilting or folding of stratal reflectors associated with faulting is also locally observed. At one site, the observed faulting is superimposed over a prominent antiformal structure, which may itself be a product of the Quaternary deformation that produced the steep normal and reverse faults. Our results suggest that faulting of the Paleozoic bedrock and younger sediments of the northern Mississippi embayment is more pervasive and less localized than previously thought.

  14. Upper Maastrichtian ammonite biostratigraphy of the Gulf Coastal Plain (Mississippi Embayment, southern USA)

    USGS Publications Warehouse

    Larina, Ekaterina; Garb, Matthew P.; Landman, Neil H.; Dastas, Natalie; Thibault, Nicolas; Edwards, Lucy E.; Phillips, George; Rovelli, Remy; Myers, Corinne; Naujokaityte, Jone

    2016-01-01

    The Cretaceous outcrop belt of the Mississippi Embayment in the Gulf Coastal Plain (GCP) spans the Cretaceous/Paleogene (K/Pg) boundary. A detailed reconstruction of this time interval is critical for understanding the nature of biotic and environmental changes preceding the end-Cretaceous Mass Extinction event and for deciphering the likely extinction mechanism (i.e., bolide impact versus volcanism). Eight sections encompassing the K/Pg succession across the Mississippi Embayment were analyzed using biostratigraphic sampling of ammonites, dinoflagellates, and nannofossils. An upper Maastrichtian ammonite zonation is proposed as follows, from oldest to youngest:Discoscaphites conradi Zone, D. minardi Zone, and D. iris Zone. Our study documents that the ammonite zonation established in the Atlantic Coastal Plain (ACP) extends to the GCP. This zonation is integrated with nannofossil and dinoflagellate biostratigraphy to provide a framework to more accurately determine the age relationships in this region. We demonstrate that ammonites and dinoflagellates are more reliable stratigraphic indicators in this area than nannofossils because age-diagnostic nannofossils are not consistently present within the upper Maastrichtian in the GCP. This biostratigraphic framework has the potential to become a useful tool for correlation of strata both within the GCP and between the GCP, Western Interior, and ACP. The presence of the uppermost Maastrichtian ammonite D. iris, calcareous nannofossil Micula prinsii, and dinoflagellates Palynodinium grallator and Disphaerogena carposphaeropsis suggests that the K/Pg succession in the GCP is nearly complete. Consequently, the GCP is an excellent setting for investigating fine scale temporal changes across the K/Pg boundary and ultimately elucidating the mechanisms causing extinction.

  15. Stratigraphic and palaeoenvironmental summary of the south-east Georgia embayment: a correlation of exploratory wells

    USGS Publications Warehouse

    Poppe, Lawrence J.; Popenoe, Peter; Poag, C. Wylie; Swift, B. Ann

    1995-01-01

    A Continental Offshore Stratigraphic Test (COST) well and six exploratory wells have been drilled in the south-east Georgia embayment. The oldest rocks penetrated are weakly metamorphosed Lower Ordovician quartz arenites and Silurian shales and argillites in the Transco 1005-1 well and Upper Devonian argillites in the COST GE-1 well. These marine strata, which are equivalent to the Tippecanoe sequence in Florida, underlie the post-rift unconformity and represent part of a disjunct fragment of Gondwana that was sutured to the North American craton during the late Palaeozoic Alleghanian orogeny. The Palaeozoic strata are unconformably overlain by interbedded non-marine Jurassic (Bajocian and younger) sandstones and shales and marginal marine Lower Cretaceous sandstones, calcareous shales and carbonates, which contain scattered beds of coal and evaporite. Together, these rocks are stratigraphically equivalent to the onshore Fort Pierce and Cotton Valley(?) Formations and rocks of the Lower Cretaceous Comanchean Provincial Series. The abundance of carbonates and evaporites in this interval, which reflects marine influences within the embayment, increases upwards, eastwards and southwards. The Upper Cretaceous part of the section is composed mainly of neritic calcareous shales and shaley limestones stratigraphically equivalent to the primarily marginal marine facies of the onshore Atkinson, Cape Fear and Middendorf Formations and Black Creek Group, and to limestones and shales of the Lawson Limestone and Peedee Formations. Cenozoic strata are primarily semiconsolidated marine carbonates. Palaeocene to middle Eocene strata are commonly cherty; middle Miocene to Pliocene strata are massive and locally phosphatic and glauconitic; Quaternary sediments are dominated by unconsolidated carbonate sands. The effects of eustatic changes and shifts in the palaeocirculation are recorded in the Upper Cretaceous and Tertiary strata.

  16. The Texas Twin Project

    PubMed Central

    Harden, K. Paige; Tucker-Drob, Elliot M.; Tackett, Jennifer L.

    2013-01-01

    Socioeconomic position, racial/ethnic minority status, and other characteristics of the macro-environment may be important moderators of genetic influence on a wide array of psychosocial outcomes. Designed to maximize representation of low socioeconomic status families and racial/ethnic minorities, the Texas Twin Project is an on-going study of school-age twins (preschool through 12th grade) enrolled in public schools in the Austin, Texas and Houston, Texas metropolitan areas. School rosters are used to identify twin families from a target population with sizable populations of African-American (18%), Hispanic / Latino (48%), and non-Hispanic White (27%) children and adolescents, over half of whom meet U.S. guidelines for classification as economically disadvantaged. Initial efforts have focused on a large-scale, family-based survey study involving both parent and child reports of personality, psychopathology, physical health, academic interests, parent-child relationships, and aspects of the home environment. In addition, the Texas Twin Project is the basis for an in-laboratory study of adolescent decision-making, delinquency, and substance use. Future directions include geographic expansion of the sample to the entire state of Texas (with a population of over 25 million people) and genotyping of participating twins. PMID:23111007

  17. Using QuickBird satellite imagery to estimate giant reed infestations in the Rio Grande Basin of Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Giant reed (Arundo donax L.) is a perennial invasive weed that presents a severe threat to agroecosystems and riparian areas in the Texas and Mexican portions of the Rio Grande Basin. The objective of this study was to use QuickBird satellite imagery to map giant reed infestations and estimate infes...

  18. Texas Almanac, 2002-2003.

    ERIC Educational Resources Information Center

    Ramos, Mary G., Ed.

    The 61st edition of the "Texas Almanac" has a reputation as the definitive source for Texas information since 1857. It contains details of the Census 2000 official population count, including statewide, county and town counts, plus an analysis of the numbers by experts at Texas's State Data Center. It includes information about politics,…

  19. Transforming Developmental Education in Texas

    ERIC Educational Resources Information Center

    Journal of Developmental Education, 2014

    2014-01-01

    In recent years, with support from the Texas Legislature, the Texas Higher Education Coordinating Board has funded various developmental education initiatives, including research and evaluation efforts, to help Texas public institutions of higher education provide more effective programs and services to underprepared students. Based on evaluation…

  20. Helminths of the ocelot from southern Texas.

    PubMed

    Pence, Danny B; Tewes, Michael E; Laack, Linda L

    2003-07-01

    In the USA, the ocelot (Leopardus pardalis) is a highly endangered felid found only in a few remaining vestiges of native thornshrub brushland in the Lower Rio Grande Valley (LRGV) of extreme southern Texas. From 1987-1998, carcasses of 15 adult ocelots that died of vehicular accidents or natural causes were examined for helminths. All cats had 1-8 (mean = 3) helminth species. All were infected with 1-101 (mean +/- SE = 32 +/- 7) Toxascaris leonina. Other helminths from these ocelots were Alaria marcianae, Brachylaima sp., Mesocestoides lineatus, Taenia rileyi, Oncicola canis, Dirofilaria immitis, Physaloptera rara, Ancylostoma tubaeformae, Cylicospirura chevreuxi, Vogeloides felis, and Metathelazia californica. Additionally, two cats had scarring of the aorta with lesions typical of those caused by Spriocerca lupi, although larval nematodes were not seen. A clinal variation in size of nearly three orders of magnitude was noted in the diplostomatid trematodes in the small intestine of one adult male ocelot. Despite the differences in size, all specimens appeared morphologically identical and were regarded as A. marcianae. Helminth prevalences and abundances, including those of potentially pathogenic species like D. immitis, were low. Although a single heartworm infection may have contributed to the death of one ocelot, helminth infections in general seemed to be of no great consequence to this endangered ocelot population. The helminth fauna of ocelots in the LRGV is reflective of that from wild felids in general; all have been reported previously from the bobcat (Lynx rufus) and mountain lion (Puma concolor) elsewhere in Texas. PMID:14567231

  1. Convective circulation during differential heating and cooling in the Minky Creek embayment of Guntersville Reservoir, data summary for 1991

    SciTech Connect

    Smith, C.S.; James, W.F.; Barko, J.W. |

    1993-06-01

    Convective circulation patterns were examined in the Minky Creek embayment of Guntersville Reservoir, Alabama, during Mid-august to mid-October 1990 and mid-May through mid-November 1991. This report describes the results obtained during 1991. Day time heating produced a warm surface layer at all stations, while the layer was often eliminated during nighttime cooling. For much of the study period, vertical temperature stratifications was minimal except during periods of heating or cooling. During differential heating, shallow regions were aften heated to the bottom while warming was confined to surface layers at deeper locations. During differential cooling water moved from shallow regions as an underflow of cool water and was replace by a return current of warmer surface waters from deeper regions. Wind influence the temperature gradients. These results support the contention that convective circulation can potentially be very important in reservoir embayments.

  2. West Texas State University.

    ERIC Educational Resources Information Center

    Roach, Ed D.

    1988-01-01

    Threats in the external environment, the arrival of a planning-oriented new president, and new regional reaccreditation criteria prompted West Texas State University to undertake a successful strategic planning venture. Leadership must focus strategic planning in a manner that recognizes the decentralized and collegial elements present in higher…

  3. ECOREGION DELINEATION IN TEXAS

    EPA Science Inventory

    Level III ecoregions are being refined and subdivided into level IV for the state of Texas. This work is consistent with ecoregion revision and subdivision that has been completed or is on-going in 37 of the conterminous United States. The two-year project is collaborative, inv...

  4. Texas Hunter Education Manual.

    ERIC Educational Resources Information Center

    Hall, Steve

    This handbook serves as a reference for the mandatory hunter education course in Texas. The "Introduction" explains hunter education's goal to produce safe, knowledgeable, responsible, and informed hunters. It also gives information related to hunting opportunities, administration, and management. Chapter 2, "Our Hunting Heritage," gives a…

  5. Tornado from Texas.

    ERIC Educational Resources Information Center

    Vail, Kathleen

    1996-01-01

    Santa Fe School Superintendent Yvonne Gonzales, the "Texas Tornado," was hired to fix a 40% student-dropout rate and a white/Hispanic gap in achievement test scores. Gonzales is an avid integrationist; relies on humor, appeasement, and persuasion tactics; and has alienated some school employees by increasing central office administrators. (MLH)

  6. Texas Irrigation Situation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The irrigation situation in Texas is an interaction between hydrology and water policies. In 2012, according to National Agricultural Statistical Service (NASS) four High Plains counties, Gainesville, Yoakum, Terry and Cochran, accounted for approximately 60% of the 150,000 acres of peanut productio...

  7. NARSTO Texas Final Report

    Atmospheric Science Data Center

    2013-03-06

    Final Report for the Texas PM2.5 Sampling and Analysis Study (March 11, ... Tropp,et al, 1998     NOTE: The Final Report is separated into the following PDF files: Section 1: ... Mass and Chemical Composition (PDF) Section 5: Summary, Conclusions, and Recommendations and Section 6 Bibliography (PDF) ...

  8. East Texas Quilts.

    ERIC Educational Resources Information Center

    Whiteside, Karen, Ed.

    1986-01-01

    Patchwork quilting is an original folk art in the United States. Pilgrims first used worn out scraps of cloth to make bed covers in an age of scarcity. Featured here are stories on East Texas Quilts, their origins, the love and hard work which goes into the making of a quilt (Ira Barr and others). The techniques needed to construct a quilt are…

  9. Trouble at Texas Southern

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    On the night of December 4, 2004, a Texas Southern University (TSU) student named Ashley Sloan was gunned down near campus, struck in the temple by a bullet after leaving a party with her friends. The murder prompted an outpouring of accusations concerning poor campus security. For many Houstonians, the shooting raised old fears of the…

  10. Outdoor Education in Texas.

    ERIC Educational Resources Information Center

    Myers, Ray H.

    In Dallas in 1970, high school outdoor education began as a cocurricular woods and waters boys' club sponsored by a community sportsman. Within one year, it grew into a fully accredited, coeducational, academic course with a curriculum devoted to the study of wildlife in Texas, ecology, conservation, hunting, firearm safety, fishing, boating and…