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Sample records for aeromagnetic surveys flown

  1. Preliminary results for an aeromagnetic survey flown over Italy using the HALO (High Altitude and LOng range) research aircraft

    NASA Astrophysics Data System (ADS)

    Lesur, V.; Gebler, A.; Schachtschneider, R.

    2012-12-01

    In June 2012 the GEOHALO mission was flown over Italy using the high altitude and long-range German research aircraft HALO (Gulfstream jet - G550). One goal of the mission was to demonstrate the feasibility of using geodetic and geophysical instrumentation on such fast flying aircraft. Several types of data were acquired including gravity, GNSS signals (reflectometry, spectrometry and occultation), laser altimetry and magnetic data. The magnetic data were collected through two independent acquisition chains placed inside under-wing containers. Each chain included a total intensity cesium magnetometer, a three-component fluxgate magnetometer, several temperature censors and a digitizer. Magnetic and temperature data were collected at a 10 Hz sampling rate. Seven parallel profiles, each around 1000 km long, were flown over the Apennine peninsula from north-west to south-east. The flight altitude was about 3500 m and the survey line spacing around 40 km. These long profiles were complemented by four crossing profiles, and a repeated flight line at a higher altitude (approx. 10500 m). The ground speed during the flight was generally around 125 m/s (450 km/h). The output from the first steps of the magnetic data processing will be shown. The measured magnetic data appear to be consistent with the expected signal.

  2. Aeromagnetic and Gravity Surveys in Afghanistan: A Web Site for Distribution of Data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Kucks, Robert P.; Hill, Patricia L.; Finn, Carol A.

    2006-01-01

    Aeromagnetic data were digitized from aeromagnetic maps created from aeromagnetic surveys flown in southeastern and southern Afghanistan in 1966 by PRAKLA, Gesellschaft fur praktische Lagerstattenforschung GmbH, Hannover, Germany, on behalf of the 'Bundesanstalt fur Bodenforschung', Hannover, Germany. The digitization was done along contour lines, followed by interpolation of the data along the original survey flight-lines. Survey and map specifications can be found in two project reports, 'prakla_report_1967.pdf' and 'bgr_report_1968.pdf', made available in this open-file report.

  3. Aeromagnetic survey map of Sacramento Valley, California

    USGS Publications Warehouse

    Langenheim, Victoria E.

    2015-01-01

    Three aeromagnetic surveys were flown to improve understanding of the geology and structure in the Sacramento Valley. The resulting data serve as a basis for geophysical interpretations, and support geological mapping, water and mineral resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense positive magnetic anomalies (for example, in the northwest part of the map). These rock types are the inferred sources, concealed beneath weakly magnetic, valley-fill deposits, of the most prominent magnetic features in the map area, the magnetic highs that extend along the valley axis. Cenozoic volcanic rocks are also an important source of magnetic anomalies and coincide with short-wavelength anomalies that can be either positive (strong central positive anomaly flanked by lower-amplitude negative anomalies) or negative (strong central negative anomaly flanked by lower-amplitude positive anomalies), reflecting the contribution of remanent magnetization. Rocks with more felsic compositions or even some sedimentary units also can cause measurable magnetic anomalies. For example, the long, linear, narrow north-trending anomalies (with amplitudes of <50 nanoteslas [nT]) along the western margin of the valley coincide with exposures of the Mesozoic Great Valley sequence. Note that isolated, short-wavelength anomalies, such as those in the city of Sacramento and along some of the major roads, are caused by manmade features.

  4. Detailed gravity and aeromagnetic surveys in the Black Rock Desert Area, Utah. Topical report

    SciTech Connect

    Serpa, L.F.; Cook, K.L.

    1980-01-01

    Aeromagnetic and gravity surveys were conducted during 1978 in the Black Rock Desert, Utah over an area of about 2400 km/sup 2/ between the north-trending Pavant and Cricket Mountains. The surveys assisted in evaluating the geothermal resources in the Meadow-Hatton Known Geothermal Resource Area (KGRA) and vicinity by delineating geophysical characteristics of the subsurface. The gravity measurements from approximately 700 new stations were reduced to complete Bouguer gravity anomaly values with the aid of a computerized terrain-correction program and contoured at an interval of 1 milligal. The aeromagnetic survey was drape flown at an altitude of 305 m (1000 ft) and a total intensity residual aeromagnetic map with a contour interval of 20 gammas was produced. Two gravity and aeromagnetic east-west profiles and one north-south profile were modeled using a simultaneous 2 1/2-dimensional modeling technique to provide a single model satisfying both types of geophysical data.

  5. High-Resolution Aeromagnetic Survey Map of Part of the Southwest Nevada Volcanic Field

    SciTech Connect

    G. Keating; R. Prueitt; A. Cogbill

    2004-06-21

    A high-resolution aeromagnetic survey was recently flown to collect data for geologic investigations in the Southwest Nevada Volcanic Field. This survey represents a marked improvement over previous (1999) surveys. The survey includes over 860 km{sup 2} covered by nearly 16,000 km of flightline with 60-m spacing and an instrument altitude of 30 m above the ground surface. Features of interest visible in the dataset include magnetic banding in the volcanic tuffs that form the faulted terrain and sharp delineation of Quaternary basalt cinder cones and lava flows. This 1:100,000-scale map includes a shaded-relief map base and a semi-transparent overlay of the aeromagnetic data, with inset maps illustrating (1) comparisons of detail between the 1999 and 2004 datasets, (2) polarity reversal banding in the volcanic tuff ridges, (3) details of the morphology of Quaternary basalt centers enhanced by aeromagnetic data, and (4) use of GIS in planning the survey.

  6. Aeromagnetic survey map of the central California Coast Ranges

    USGS Publications Warehouse

    Langenheim, V.E.; Jachens, R.C.; Moussaoui, K.

    2009-01-01

    This aeromagnetic survey was flown as part of a Cooperative Research and Development Agreement (CRADA) with the Pacific Gas and Electric Company and is intended to promote further understanding of the geology and structure in the central California Coast Ranges by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because rocks with more felsic compositions, such as the porphyritic granodiorite-granite of the La Panza Range, and even some sedimentary units, also can cause measurable magnetic anomalies.

  7. Maps showing aeromagnetic survey and geologic interpretation of the Chignik and Sutwik Island quadrangles, Alaska

    USGS Publications Warehouse

    Case, J.E.; Cox, D.P.; Detra, D.E.; Detterman, R.L.; Wilson, F.H.

    1981-01-01

    An aeromagnetic survey over part of the Chignik and Sutwik Island quadrangles, on the southern Alaska Peninsula, was flown in 1977 as part of the Alaska mineral resource assessment program (AMRAP). Maps at scales 1:250,000 and 1:63,360 have been released on open-file (U.s. Geological Survey, 1978a, 1978b). This report includes the aeromagnetic map superimposed on the topographic base (sheet 1) and an interpretation map superimposed on the topographic and simplified geologic base (sheet 2). This discussion provides an interpretation of the aeromagnetic data with respect to regional geology, occurrence of ore deposits and prospects, and potential oil and gas resources. The survey was flown along northwest-southeast lines, spaced about 1.6 km apart, at a nominal elevation of about 300 m above the land surface. A proton-precession magnetometer was used for the survey, and the resulting digital data were computer contoured at intervals of 10 and 50 gammas (sheet 1). The International Geomagnetic Reference Field (IGRF) of 1965, updated to 1977, was removed from the total field data.

  8. Status of aeromagnetic survey coverage of Yucca Mountain and vicinity to a radius of about 140 kilometers, southwestern Nevada and southeastern California, 1992

    SciTech Connect

    Sikora, R.F.; Ponce, D.A.; Oliver, H.W.

    1993-12-31

    Fifty aeromagnetic surveys in the southwestern part of Nevada and the southeastern part of California have been evaluated to assess the quality and coverage of aeromagnetic data within 140 kilometers (km) of a potential nuclear waste repository at Yucca Mountain, Nevada. The compilation shows that all the study area is covered by aeromagnetic surveys, but in some areas, particularly in the Death Valley region, new surveys flown with closer flight line spacing and lower elevations than the existing coverage are needed. In addition, the California part of the study area needs to be analytically continued downward to 305 meters (m) above ground level to provide a consistent data set for interpretation of subsurface geologic structures.

  9. Aeromagnetic and electrical resistivity surveys of Ascension Island

    SciTech Connect

    Ross, H.P.; Nielson, D.L.

    1995-12-31

    As part of an evaluation of the geothermal energy potential, the University of Utah Research Institute conducted a detailed aeromagnetic survey of Ascension Island, South Atlantic Ocean, in 1983. Interpretation of the data, supported by three-dimensional numerical modeling, indicated structural features and a low-magnetization area near the center of the island. Reconnaissance and detailed electrical resistivity surveys were completed in 1984 and these identified a zone of low apparent resistivity which corresponds to anomalous temperatures and alteration well above a high-temperature geothermal system.

  10. Detailed gravity and aeromagnetic surveys of the Cove Fort-Sulphurdale KGRA and vicinity, Millard and Beaver Counties, Utah. Topical report

    SciTech Connect

    Cook, K.L.; Serpa, L.F.; Pe, W.

    1980-01-01

    A detailed gravity survey (comprising 231 stations over about 900 km/sup 2/) was made in the Cove Fort-Sulphurdale Known Geothermal Resource area (KGRA) and vicinity, Millard and Beaver counties, Utah to assist in the appraisal of the potential of this area as a geothermal resource. The survey reinforced the results and information obtained in the previous regional gravity surveys comprising 522 stations. The gravity data from about 700 stations were reduced and compiled as a terrain-corrected (out to 20 km) Bouguer gravity anomaly map with 1-mgal contour interval. In August 1975, an aeromagnetic survey was flown over part of the survey area at a constant barometric elevation of 12,000 ft (3660 m). These aeromagnetic data are used to supplement the interpretation of the gravity data. The aeromagnetic field intensity residual anomaly map and the second-order polynomial residual aeromagnetic map (obtained by removing a second-order polynomial surface) are presented with a 20-gamma contour interval. Two north-south profiles and one east-west profile were selected for magnetic interpretative modeling. The two north-south profiles were also stacked and averaged over 6-km-wide strips and modeled. The occurrences of hydrothermal alteration, hot spring deposits, and flowing hot springs coincide with inferred fault zones. No evidence of extensive alteration can be interpreted from the magnetic data.

  11. Preliminary grid data and maps for an aeromagnetic survey of the Taylor mountains quadrangle and a portion of the Bethel quadrangle, Alaska

    USGS Publications Warehouse

    Saltus, R.W.; Milicevic, B.

    2004-01-01

    A preliminary data grid and maps are presented for an aeromagnetic survey of the Taylor Mountains and a portion of the Bethel quadrangles, Alaska. The aeromagnetic survey was flown by McPhar Geosurveys Ltd. for the U.S. Geological Survey (USGS). A flight-line spacing of 1,600 meters (1 mile) and nominal flight height of 305 meters (1,000 feet) above topography (draped) was used for the survey. The preliminary data grid has a grid cell size of 350 meters (1150 feet). Final data processing and quality control have not been applied to these data. The purpose of this preliminary data release is to allow prompt public access to these data, which are of interest for active mineral exploration in the region. A more complete data release and description will be published later once the final data processing is complete.

  12. Aeromagnetic surveys in the seas around Japan in 1980

    NASA Astrophysics Data System (ADS)

    Utashiro, S.; Oshima, S.; Kaneko, T.

    1984-07-01

    Aeromagnetic surveys in the seas around Japan were carried out in 1979 to 1980 by a YS-11 aircraft of the Maritime Safety Agency of Japan using a new type of airborne magnetometer system. The new type of airborne magnetometer system consists of a ring-core type three-component fluxgate magnetometer, an inertial sensing system, a fish-eye camera to measure the true north, an 8-bit microcomputer and a proton magnetometer. The VLF/OMEGA system is used to fix the position of the aircraft. Tracks extended to about 600 nautical miles off the coast of the Japanese islands in the Sea of Japan and the North-West Pacific Ocean. Average spacing between tracks was about 80 miles. The flights were carried out at an altitude of 9500 feet. From the survey results, magnetic charts of the seven geomagnetic elements for 1980 over the sea around Japan were compiled by the method of least squares using a polynomial. Also, the contour charts of secular variation in 1980 were compiled.

  13. Digital data from the northeast Tusas Mountains aeromagnetic survey, north-central New Mexico

    USGS Publications Warehouse

    Drenth, B.J.; Grauch, V.J.S.; ,

    2011-01-01

    This report contains digital data, image files, and text files describing data formats and survey procedures for a high-resolution aeromagnetic survey in the northeast Tusas Mountains region of north-central New Mexico. The survey covers a large portion of the Tres Piedras Ranger District of the Carson National Forest and adjacent areas, northwest of the town of Tres Piedras. Several related and derivative products from these data are also presented as grids and images, including radar-altimeter heights, analytically draped aeromagnetic data, the elevation surface used for draping, and reduced-to-pole aeromagnetic data. Images are presented in various formats and are intended to be used as input to geographic information systems, standard graphics software, or map-plotting packages.

  14. An aeromagnetic survey in the Valley of Ten Thousand Smokes, Alaska. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Anma, K.

    1971-01-01

    Geologic and magnetic studies of the Katmai area have further demonstrated the close relationship between the Katmai Caldera, Novarupta plug, and the pyroclastic flows in the Valley of Ten Thousand Smokes. The magnetic fields observed appear to be associated with the thickness of the pyroclastic flow and the different rock units within it for lower flight levels, and also the contrast between the valley fill and the rock units at the Valley margins. Consistent magnetic anomalies are associated with the larger fumarole lines, which were presumably sites of large scale activity, while the smaller fumaroles are not usually seen in the aeromagnetic map. A possible correlation between low positive anomalies and nuee ardente deposits was revealed by the aeromagnetic survey, but was not strong. A ground survey was also carried out in several parts of the Valley with a view to detailed delineation of the magnetic signatures of the pyroclastic flow, as an aid to interpreting the aeromagnetic date.

  15. Aeromagnetic Survey of the Amargosa Desert, Nevada and California: A Tool for Understanding Near-Surface Geology and Hydrology

    USGS Publications Warehouse

    Blakely, Richard J.; Langenheim, V.E.; Ponce, David A.; Dixon, Gary L.

    2000-01-01

    A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were oriented east-west, spaced 400 m (0.25 mi) apart, and flown at an altitude of 150 m (500 ft) above terrain, or as low as permitted by safety considerations. Characteristic magnetic anomalies occur over volcanic terranes, such as Yucca Mountain and the Greenwater Range, and over Proterozoic basement rocks, such as Bare Mountain and the Black Mountains. Linear magnetic anomalies caused by offsets of volcanic rocks permit detailed mapping of shallow faults in volcanic terranes. Of particular interest are subtle anomalies that overlie alluvial deposits at Devils Hole and Pahrump Valley. Alignments of springs along magnetic anomalies at these locales suggest that these anomalies are caused by faults that cut the alluvium, displace magnetic rocks at depth, and eventually influence ground-water flow. Linear magnetic anomalies over the Funeral Mountains appear to coincide with a prominent set of north-northeast-striking faults that cut the Precambrian Stirling Quartzite, rocks that are typically nonmagnetic. The position and orientation of these anomalies with respect to springs north of Furnace Creek suggest that the faults may act as conduits for the flow of water from the north into Death Valley, but the mineralogical cause of the anomalies is unknown.

  16. Survey Parameters and Availability of Low-level Aeromagnetic Data for Geomagnetic Field Modelling

    NASA Technical Reports Server (NTRS)

    Hood, Peter

    1992-01-01

    Since aeromagnetic surveying started immediately after World War II, a considerable area of the earth's surface both onshore (in excess of 25 million sq. km) has been magnetically surveyed. For about the first 15 years or so, fluxgate magnetometers were employed in aeromagnetic surveys, but the introduction of proton free-precession magnetometers resulted in absolute readings being recorded. Proton precession magnetometers have now been replaced to a large extent by the more sensitive optical absorption magnetometers. Some care has to be taken to calibrate aeromagnetic survey systems and this is best done using a calibration range tied to a magnetic observatory so that accuracies of 10nT or better are achieved for the total field values recorded. Survey navigation has always posed a problem for aeromagnetic surveys, especially offshore. Over land, vertically pointed 35 mm cameras were initially used to recover the aircraft track using a combination of aerial photos and topographic maps. Over featureless areas, it was necessary to utilize existing electronic positioning systems such as Loran C or set up special navigation systems. The advent of the satellite-based Global Positioning Systems (GPS) has to a larger extent solved the navigational problem because there is now almost continuous worldwide coverage to 10 m accuracy in the differential mode. The resultant aeromagnetic data is normally compiled into contour maps in which the diurnal variation and aircraft heading effects are removed. The resultant digital data are normally made publicly available both in gridded and profile form along with the published contour maps. Most aeromagnetic coverage has been obtained in the developed western countries, but elsewhere a considerable amount of surveying has been carried out; as an example, some 80 percent of Africa has been surveyed mostly as a result of aid programs. The data is usually held by the national geological survey or equivalent organizations, but in a

  17. High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

    NASA Astrophysics Data System (ADS)

    Ponce, D. A.; Mangan, M.; McPhee, D.

    2013-12-01

    A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

  18. Revision of an aeromagnetic survey of the Lathrop Wells area, Nevada

    SciTech Connect

    Langenheim, V.E.; Carle, S.F.; Ponce, D.A.; Phillips, J.D.

    1991-09-01

    Review of an aeromagnetic survey of the Lathrop Wells area revealed two independent problems: (1) regularly spaced intervals of data amounting to one-quarter of the original flightline data are missing and (2) horizontal positioning errors are common. The horizontal positioning errors are as large as 900 m (2950 ft), far greater than the 50-m (150-ft) positioning uncertainties for similar, nearby surveys. Missing records were restored by using interpolated values from original contract grids. The positions of the flightlines were corrected by photographic methods of flight path recovery. The uncertainty of the corrected positions of the flightline data is about 150 m (500 ft). A new version of the aeromagnetic map of the Lathrop Wells survey has been prepared using the restored and repositioned data points. 5 refs., 6 figs., 2 tabs.

  19. Impact of human activities on the geomagnetic field of Antarctica: a high resolution aeromagnetic survey over Mario Zucchelli Station.

    PubMed

    Armadillo, E; Bozzo, E; Gambetta, M; Rizzello, D

    2012-10-15

    Environmental protection of Antarctica is a fundamental principle of the Antarctic Treaty. Impact assessment and significance evaluation are due for every human activity on the remote continent. While chemical and biological contaminations are widely studied, very little is known about the electromagnetic pollution levels. In this frame, we have evaluated the significance of the impact of Mario Zucchelli Antarctic Station (Northern Victoria Land) on the local geomagnetic field. We have flown a high resolution aeromagnetic survey in drape mode at 320m over the Station, covering an area of 2km(2). The regional and the local field have been separated by a third order polynomial fitting. After the identification of the anthropic magnetic anomaly due to the Station, we have estimated the magnetic field at the ground level by downward continuation with an original inversion scheme regularized by a minimum gradient support functional to avoid high frequency noise effects. The resulting anthropic static magnetic field at ground extends up to 650m far from the Station and reaches a maximum peak to peak value of about 2800nT. This anthropic magnetic anomaly may interact with biological systems, raising the necessity to evaluate the significance of the static magnetic impact of human installations in order to protect the electromagnetic environment and the biota of Antarctica.

  20. Impact of human activities on the geomagnetic field of Antarctica: a high resolution aeromagnetic survey over Mario Zucchelli Station.

    PubMed

    Armadillo, E; Bozzo, E; Gambetta, M; Rizzello, D

    2012-10-15

    Environmental protection of Antarctica is a fundamental principle of the Antarctic Treaty. Impact assessment and significance evaluation are due for every human activity on the remote continent. While chemical and biological contaminations are widely studied, very little is known about the electromagnetic pollution levels. In this frame, we have evaluated the significance of the impact of Mario Zucchelli Antarctic Station (Northern Victoria Land) on the local geomagnetic field. We have flown a high resolution aeromagnetic survey in drape mode at 320m over the Station, covering an area of 2km(2). The regional and the local field have been separated by a third order polynomial fitting. After the identification of the anthropic magnetic anomaly due to the Station, we have estimated the magnetic field at the ground level by downward continuation with an original inversion scheme regularized by a minimum gradient support functional to avoid high frequency noise effects. The resulting anthropic static magnetic field at ground extends up to 650m far from the Station and reaches a maximum peak to peak value of about 2800nT. This anthropic magnetic anomaly may interact with biological systems, raising the necessity to evaluate the significance of the static magnetic impact of human installations in order to protect the electromagnetic environment and the biota of Antarctica. PMID:22706521

  1. Low-level aeromagnetic surveying for petroleum in arctic Alaska

    SciTech Connect

    Donovan, T.J.; Hendricks, J.D.; Roberts, A.A.; Eliason, P.T.

    1989-01-01

    Magnetic anomalies of high wave number measured over oil fields have been interpreted as reflecting abundant near-surface magnetic minerals formed as a direct result of petroleum seepage. The investigation reported here, undertaken during the summer of 1979, demonstrates that these kinds of anomalies are associated with known occurrences of petroleum in northern Alaska. Because routine geological and geophysical information is especially difficult and expensive to acquire in northern Alaska, rapidly gathered and relatively inexpensive aeromagnetic data that might conceivably serve as an indirect indicator of hydrocarbons could have an impact on exploration activities there. Additionally, documentation of microseepage-related phenomena is an important step toward understanding petroleum microseepage in a permafrost environment. Rocks above and adjacent to the Barrow arch, a buried regional feature along the north coast of Alaska, are a primary habitat for oil and gas, but the geologic framework and the geology of petroleum occurrence are complex. Upper Devonian to lowermost Cretaceous carbonate and clastic rocks derived from northern sources were deposited in a basin that deepened southward. These rocks contain four of the five major reservoirs in the Prudhoe Bay field, which is located on the arch 330 km southeast of Barrow. Formation of the ancestral Brooks Range and the opening of the Arctic Ocean in the Late Jurassic and Early Cretaceous caused southern sediment sources to replace the northern landmass. Subsequent subsidence and tilting of the continental margin toward the opening Arctic Ocean resulted in the formation of the Barrow arch. The Barrow arch was onlapped and overlapped in Late Cretaceous and Tertiary times by a series of clastic wedges that filled northeastward-migrating foredeeps.

  2. Aeromagnetic Survey in Western Afghanistan: A Web Site for Distribution of Data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Kucks, Robert P.; Hill, Patricia L.; Finn, Carol A.

    2006-01-01

    Aeromagnetic and related data were digitized from 1976 magnetic field and survey route location maps of western Afghanistan. The magnetic field data were digitized along contour lines from 33 maps in a series entitled 'Map of Magnetic Field of Afghanistan (Western Area) Delta-Ta Isolines,' compiled by V. A. Cnjagev and A. F. Bukhmastov. The survey route location data were digitized along flight-lines located on 33 maps in a series entitled 'Survey Routes Location and Contours of Flight Equal Altitudes. Western Area of Afghanistan,' compiled by Z. A. Alpatova, V. G. Kurnosov, and F. A. Grebneva.

  3. High Resolution, Low Altitude Aeromagnetic and Electromagnetic Survey of Mt Rainier

    USGS Publications Warehouse

    Rystrom, V.L.; Finn, C.; Deszcz-Pan, Maryla

    2000-01-01

    In October 1996, the USGS conducted a high resolution airborne magnetic and electromagnetic survey in order to discern through-going sections of exposed altered rocks and those obscured beneath snow, vegetation and surficial unaltered rocks. Hydrothermally altered rocks weaken volcanic edifices, creating the potential for catastrophic sector collapses and ensuing formation of destructive volcanic debris flows. This data once compiled and interpreted, will be used to examine the geophysical properties of the Mt. Rainier volcano, and help assist the USGS in its Volcanic Hazards Program and at its Cascades Volcano Observatory. Aeromagnetic and electromagnetic data provide a means for seeing through surficial layers and have been tools for delineating structures within volcanoes. However, previously acquired geophysical data were not useful for small-scale geologic mapping. In this report, we present the new aeromagnetic and electromagnetic data, compare results from previously obtained, low-resolution aeromagnetic data with new data collected at a low-altitude and closely spaced flightlines, and provide information on potential problems with using high-resolution data.

  4. Digital Data From the Taos West Aeromagnetic Survey in Taos County, New Mexico

    USGS Publications Warehouse

    Bankey, Viki; Grauch, V.J.S.; Drenth, B.J.; ,

    2007-01-01

    This report contains digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during a survey covering the southwestern portion of Taos County west of the Town of Taos, New Mexico, in October, 2006. Several derivative products from these data are also presented as grids and images, including reduced-to-pole data and data continued to a reference surface. Images are presented in various formats and are intended to be used as input to geographic information systems, standard graphics software, or map plotting packages.

  5. Aeromagnetic surveys across Crater Flat and parts of Yucca Mountain, Nevada

    SciTech Connect

    Sikora, R.F.; Campbell, D.L.; Kucks, R.P.

    1995-12-31

    As part of a study to characterize a potential nuclear waste repository at Yucca Mountain, aeromagnetic surveys were conducted in April 1993 along the trace of a planned seismic profile across Crater Flat and parts of Yucca Mountain. This report includes a presentation and preliminary interpretation of the data. The profiles are at scales of 1:100,000. Also included are a gridded color contour map of the newly acquired data and a discussion of the likely applicability of very-low-frequency (VLF) electromagnetic surveys to Yucca Mountain investigations.

  6. Russian aeromagnetic surveys of the Prince Charles Mountains and adjacent regions into the 21st century

    NASA Astrophysics Data System (ADS)

    Golynsky, Alexander; Golynsky, Dmitry; Kiselev, Alexander; Masolov, Valery

    2014-05-01

    Russian aeromagnetic investigations in the Prince Charles Mountains (PCM) and surrounding areas, seek to contribute data on the tectonics of Precambrian igneous belts and cratonic fragments, the crustal structure of the Lambert Rift system and other major aspects of Antarctic geology, critical to understanding continental growth processes (Golynsky et al., 2006). Over the past decade, the Polar Marine Geoscience Expedition projects acquired approximately 77,400 line-km of aeromagnetic data over the largely ice-covered regions of MacRobertson Land and Princess Elizabeth Land. The airborne surveys were performed with a standard profile spacing of 5 km and tie-line interval of 15-25 km. The total amount of the Russian aeromagnetic data collected in this region exceeded more than 165,000 line-km. Together with the PCMEGA and AGAP surveys (Damaske and McLean, 2005; Ferraccioli et al., 2011) the PMGE dataset forms the longest transect ever mapped in East Antarctica exceeding 1950 km in length. Several distinct crustal subdivisions are clearly differentiated in the magnetic data. The high-amplitude positive anomalies that extend around the Vestfold Hills and Rauer Islands are likely be attributed to the southern boundary of high-grade metamorphic Late Archean craton. The northern PCM that are composed by ~1 Ga orthogneiss and charnockite display a predominantly northeasterly trending magnetic fabric that continues to the eastern shoulder of the Lambert Rift. The aeromagnetic data from the Southern PCM reveal the spatial boundary of the Archaean Ruker Terrane that is characterized by a short-wavelength anomalies and the prominent Ruker Anomaly that is associated with a banded iron formation. The prominent alternating system of linear NE-SW positive and negative anomalies over the eastern shoulder of the Lambert Rift may reflect the western boundary of the Princess Elizabeth Land cratonic(?) block, although its relationships and tectonic origin remained largely ambiguous

  7. Aeromagnetic Survey in Afghanistan: A Website for Distribution of Data

    USGS Publications Warehouse

    Abraham, Jared D.; Anderson, Eric D.; Drenth, Benjamin J.; Finn, Carol A.; Kucks, Robert P.; Lindsay, Charles R.; Phillips, Jeffrey D.; Sweeney, Ronald E.

    2007-01-01

    Afghanistan's geologic setting indicates significant natural resource potential While important mineral deposits and petroleum resources have been identified, much of the country's potential remains unknown. Airborne geophysical surveys are a well accepted and cost effective method for obtaining information of the geological setting of an area without the need to be physically located on the ground. Due to the security situation and the large areas of the country of Afghanistan that has not been covered with geophysical exploration methods a regional airborne geophysical survey was proposed. Acting upon the request of the Islamic Republic of Afghanistan Ministry of Mines, the U.S. Geological Survey contracted with the Naval Research Laboratory to jointly conduct an airborne geophysical and remote sensing survey of Afghanistan.

  8. Digital Data from the Great Sand Dunes and Poncha Springs Aeromagnetic Surveys, South-Central Colorado

    USGS Publications Warehouse

    Drenth, B.J.; Grauch, V.J.S.; Bankey, Viki; New Sense Geophysics, Ltd.

    2009-01-01

    This report contains digital data, image files, and text files describing data formats and survey procedures for two high-resolution aeromagnetic surveys in south-central Colorado: one in the eastern San Luis Valley, Alamosa and Saguache Counties, and the other in the southern Upper Arkansas Valley, Chaffee County. In the San Luis Valley, the Great Sand Dunes survey covers a large part of Great Sand Dunes National Park and Preserve and extends south along the mountain front to the foot of Mount Blanca. In the Upper Arkansas Valley, the Poncha Springs survey covers the town of Poncha Springs and vicinity. The digital files include grids, images, and flight-line data. Several derivative products from these data are also presented as grids and images, including two grids of reduced-to-pole aeromagnetic data and data continued to a reference surface. Images are presented in various formats and are intended to be used as input to geographic information systems, standard graphics software, or map plotting packages.

  9. The first aeromagnetic survey in the Arctic: results of the Graf Zeppelin airship flight of 1931

    NASA Astrophysics Data System (ADS)

    Raspopov, O. M.; Sokolov, S. N.; Demina, I. M.; Pellinen, R.; Petrova, A. A.

    2013-03-01

    In July of 1931, on the eve of International Polar Year II, an Arctic flight of the Graf Zeppelin rigid airship was organized. This flight was a realization of the idea of F. Nansen, who advocated the use of airships for the scientific exploration of the Arctic territories, which were poorly studied and hardly accessible at that time. The route of the airship flight was Berlin - Leningrad - Arkhangelsk - Franz Josef Land - Severnaya Zemlya - the Taimyr Peninsula - Novaya Zemlya - Arkhangelsk - Berlin. One of scientific goals of the expedition was to measure the H and D geomagnetic field components. Actually, the first aeromagnetic survey was carried out in the Arctic during the flight. After the expedition, only preliminary results of the geomagnetic measurements, in which an anomalous behavior of magnetic declination in the high-latitude part of the route was noted, were published. Our paper is concerned with the first aeromagnetic measurements in the Arctic and their analysis based on archival and modern data on the magnetic field in the Barents and Kara sea regions. It is shown that the magnetic field along the flight route had a complicated structure, which was not reflected in the magnetic charts of those times. The flight was very important for future development of aero- and ground-based magnetic surveys in the Arctic, showing new methods in such surveys.

  10. Aeromagnetic survey over US to advance geomagnetic research

    USGS Publications Warehouse

    Hildenbrand, T.G.; Blakely, R.J.; Hinze, W. J.; Keller, Gordon R.; Langel, R.A.; Nabighian, M.; Roest, W.

    1996-01-01

    A proposed high-altitude survey of the US offers an exciting and cost effective opportunity to collect magnetic-anomaly data. Lockheed Martin Missile and Space Company is considering funding a reimbursable ER-2 aircraft mission to collect synthetic aperture radar (SAR) imagery at an altitude of about 21 km over the conterminous US and Alaska. The collection of total and vector magnetic field data would be a second objective of the flight. These data would provide insight on fundamental tectonic and thermal processes and give a new view of the structural and lithologic framework of the crust and upper mantle.

  11. Aeromagnetic Survey of Taylor Mountains Area in Southwest Alaska, A Website for the Distribution of Data

    USGS Publications Warehouse

    U.S. Geological Survey

    2006-01-01

    USGS Data Series Report for the release of aeromagnetic data collected in the Taylor Mountains Area of Southwest Alaska and associated contractor reports. Summary: An airborne high-resolution magnetic and coincidental horizontal magnetic gradiometer survey was completed over the Taylor Mountains area in southwest Alaska. The flying was undertaken by McPhar Geosurveys Ltd. on behalf of the United States Geological Survey (USGS). First tests and calibration flights were completed by April 7, 2004, and data acquisition was initiated on April 17, 2004. The final data acquisition and final test/calibrations flight was completed on May 31, 2004. Data acquired during the survey totaled 8,971.15 line-miles.

  12. A High-Resolution Aeromagnetic Survey to Identify Buried Faults at Dixie Valley, Nevada

    SciTech Connect

    Smith, Richard Paul; Grauch, V. J. S.; Blackwell, David D.

    2002-09-01

    Preliminary results from a high-resolution aeromagnetic survey (200m line spacing) acquired in Dixie Valley early in 2002 provide confirmation of intra-basin faulting based on subtle surface indications. In addition the data allow identification of the locations and trends of many faults that have not been recognized at the surface, and provide a picture of intrabasin faulting patterns not possible using other techniques. The data reveal a suite of northeasterly-trending curving and branching faults that surround a relatively coherent block in the area of Humboldt Salt Marsh, the deepest part of the basin. The producing reservoir occurs at the north end of this coherent block, where rampart faults from the northwest side of the valley merge with anthithetic faults from the central and southeast parts of the valley.

  13. Aeromagnetic survey using an unmanned autonomous helicopter over Tarumae Volcano, northern Japan

    NASA Astrophysics Data System (ADS)

    Hashimoto, Takeshi; Koyama, Takao; Kaneko, Takayuki; Ohminato, Takao; Yanagisawa, Takatoshi; Yoshimoto, Mitsuhiro; Suzuki, Eiichi

    2014-09-01

    Unmanned aerial vehicles (UAVs) have recently received attention in various research fields for their ability to perform measurements, surveillance, and operations in hazardous areas. Our application is volcano surveillance, in which we used an unmanned autonomous helicopter to conduct a dense low-altitude aeromagnetic survey over Tarumae Volcano, northern Japan. In autonomous flight, we demonstrated positioning control with an accuracy of ~10 m, which would be difficult for an ordinary crewed vehicle. In contrast to ground-based magnetic measurement, which is highly susceptible to local anomalies, the field gradient in the air with a terrain clearance of 100 to 300 m was fairly small at 1 nT/m. This result suggests that detection of temporal changes of an order of 10 nT may be feasible through a direct comparison of magnetic data between separate surveys by means of such a system, rather than that obtained by upward continuation to a common reduction surface. We assessed the temporal magnetic changes in the air, assuming the same remagnetising source within the volcano that was recently determined through ground surveys. We conclude that these expected temporal changes would reach a detection level in several years through a future survey in the air with the same autonomous vehicle.

  14. A Possibility of the Aeromagnetic Survey by a Small Unmanned Aerial Vehicles, Ant-Plane

    NASA Astrophysics Data System (ADS)

    Funaki, M.

    2004-12-01

    Magnetic surveys by helicopters and airplanes are a useful technique to estimate the geological structure under the ice sheets in Antarctica. However, it is not easy to employ this due to the transportation of the planes, logistic supports, security, and financial problems. Members of Ant-Plane Project have investigated the unmanned aerial vehicles (UAV, Ant-Plane) for the solution of the problems. Recently the aeromagnetic survey is verified by a model airplane navigated by GPS and a magneto-resistant (MR) magnetometer. The airplane (Ant-Plane) consists of 2m wing length, 2-cycles and 2-cylinder 85cc gasoline engine, GPS navigation system by microcomputer and radio telemeter system. The total weight is 15kg including 2 litter fuels, the MR magnetometer, a video camera and an emergency parachute. The speed is 130 km/h and maximum height is 2000m. The magnetometer system consists of a 3- component MR magnetometer, GPS and data logger. Three components of magnetic field, latitude, longitude, altitude, number of satellite and time are recorded in every second during 3 hours. The sensitivity of the magnetometer is 7 nT and we use a total magnetic field intensity for magnetic analysis due to unknown heading of the plane. November 2003 we succeeded the magnetic survey by the Ant-Plane at the slope of Sakurajima Volcano, Kyushu, Japan. The plane rotated 9 times along the programmed route of about 4x1 km, total flight distance of 80 km, keeping the altitude of 700 m. Consequently we obtained almost similar field variation on the route. The maximum deviation of each course was less than 100 m. Therefore, we concluded that the aeromagnetic survey in the relatively large anomaly areas can be performed by Ant-Plane with the MR magnetometer system. Finally the plane flew up 1400m with a video camera to take the photo of active volcano Sakurajima (1117m). It succeeded to take photos of craters through steam from the volcano.

  15. Aeromagnetic survey by a model helicopter at the ruin of ironwork refinement

    NASA Astrophysics Data System (ADS)

    Funaki, M.; Nishioka, T.

    2007-12-01

     It is difficult to detect the magnetic anomaly resulting from the small scale of magnetic sources as archeological or historical ruins by a helicopter due to the restraint of the low altitude flights in the narrow area. Although a relatively small unmanned helicopters has been commercialized for agriculture use etc., it is too expensive for aeromagnetic surveys. We have developed a small autonomous unmanned helicopter which modified a model helicopter for aeromagnetic survey. A model helicopter (Hirobo Co.; SF40) with a 40cc gasoline engine, length of 143cm from the nose to the tail and dry weight of 15 kg is selected in this study. The irradiated magnetic field from the bottom-center of skid of SF40 was the total magnetic field (R)=3511 nT, inclination (I)=12 degrees and declination (D)=138 degrees. It was reduced to about 1 nT at 3 m downward from the skid during the hovering. When SF40 was covered with a magnetic shield film (Amolic sheet), the distance to measure 1nT diminished to 2 m. As shielding whole body with the film is not effective for reliable and safety flights, the only servomotors having the strong magnetization were shielded by the film. The autonomous flights based on GPS data succeeded. As the control system was too large and heavy for SF40, we are developing more simple and small navigation system for this project. Magnetometer system consists of a 3-axis fluxgate magnetometer, data logger, GPS and battery, recording every second of x, y and z magnetic fields, latitude, longitude, altitude and satellite number during 3 hours. The total weight of the system is 400g. The system was hanged to 2m lower from the skid by a rope (Bird magnetometer) or 2m front form the nose by a carbon fiber pipe (Stinger magnetometer) in order to avoid the magnetic field of SF40. However, the bird magnetometer was not suitable due to the strong noise resulting from the swing of the sensor. An archeological ruin of the ironwork refinement aged 15th century in

  16. Tectonic implications of a high-resolution aeromagnetic survey of the Portland basin, Oregon and Washington

    SciTech Connect

    Blakeley, R.J.; Wells, R.E. ); Beeson, M.H. . Geology Dept.); Madin, I.P. ); Popowski, T. ); Yelin, T.S. . Geological Survey)

    1993-04-01

    A high-resolution aeromagnetic survey of the Portland-Vancouver metropolitan area was conducted by the US Geological Survey during September, 1992, to determine the location and extent of faults in the area, especially where concealed by vegetation, water, and urban development. Magnetic anomalies in this area are caused principally by three volcanic units: Eocene basaltic basement, presumably representing an accreted oceanic terrane; folded and faulted flows of the Miocene Columbia River Basalt Group; and locally erupted basalt of Plio-Pleistocene age. Linear magnetic anomalies correlate with several known faults in these rocks, while other anomalies may reflect previously unrecognized faults beneath covered areas. The northwest-striking Portland-Hills fault, which lies beneath downtown Portland and which appears to be seismically active at the M [<=] 3 level, is clearly represented in the magnetic data as an anomaly extending southeast to the Clackamas River drainage, a total distance in excess of 50 km. This fault is thought to be the southwestern boundary of a complex pull-apart zone that formed the Portland Basin. The northeastern boundary of the pull-apart zone, the frontal fault northeast of downtown Vancouver, is less apparent in the magnetic data. The overall length of the magnetic anomaly associated with the Portland Hills fault indicates that the fault is at least 50 km in length. If the Portland Hills fault is seismically active along this entire length, seismic risk to the Portland-Vancouver metropolitan area may be greater than previously suspected.

  17. Preliminary analysis of gravity and aeromagnetic surveys of the Timber Mountain Area, southern Nevada

    SciTech Connect

    Kane, M.F.; Webring, M.W.; Bhattacharyya, B.K.

    1981-12-31

    Recent (1977 to 1978) gravity and aeromagnetic surveys of the Timber Mountain region, southern Nevada, have revealed new details of subsurface structure and lithology. The data strongly suggest that deformation caused by volcanic events has been accommodated along straight-line faults combining in such a fashion as to given a curvilinear appearance to regional structure. The magnetic data suggest that rock units in the central graben and along the southeast margin of Timber Mountain may have been altered, perhaps thermally, from their original state. The gravity data indicate that the south part of the Timber Mountain is underlain by relatively dense rock possibly intrusive rock, like that which crops out along its southeast side. The gravity data also suggest that the Silent Canyon caldera may extend considerably south of its presently indicated southern limit and may underlie much of the area of Timber Mountain. The moat areas appear to be more rectangular or triangular than annular in shape. The southern part of Timber Mountain caldera is separated from the Yucca Mountain area to the south by a triangular horst. The structural relations of the rock units making up the horst are complex. Several linear terrain features in the southern part of the caldera area are closely aligned with geophysical features, implying that the terrain features are fault-controlled.

  18. Exploration application of high resolution aeromagnetic surveys in the Gulf of Mexico, USA

    SciTech Connect

    Berger, Z.; Reudavey, G.

    1996-08-01

    High resolution magnetic surveys provide an excellent tool for mapping geological structures in a wide range of tectonic settings and geographical areas. The improved mapping capabilities of these surveys are achieved by: (1) Advanced high resolution data acquisition techniques including lower altitudes, tighter line spacing, and broad-band frequency retention, and (2) advanced data processing and display techniques such as depth slicing, micro-leveling and image processing. Newly acquired high resolution aeromagnetic surveys of Cameron and Vermilion areas have been recently interpreted. The results of this study can be summarized as follows: (1) The magnetic images of high frequency domain can be used to map near surface salt fastuws and growth faults. These images can also be used to define the shape of the salt diapers and assess their interaction with different fault systems. (2) Interpretation and modeling of different depth-slice images can be used to determine the thickness of different salt bodies and establish their progressive changes with depth. This technique can also be used to outline potential sedimentary basins at different depths. (3) Magnetic images of mid to low frequency domains can be used to establish the structural fabric of sub-salt terrain. The result of this study is presented with a series of posters that illustrate the inventory of salt and fault features identified on different magnetic images and their correlation with subsurface structures which are recognized with well and seismic data. Magnetic profiles and models are also being used to illustrate how the magnetic data was calibrate to the recorded travel-time of seismic data and related isochron and time structure maps.

  19. Coal, clinkers and aeromagnetics

    SciTech Connect

    Friedberg, J.L.; Crosby, R.O.

    1982-04-01

    Aeromagnetic surveying can be useful for delineating beds of coal that have undergone natural burn. A very strong correlation has been established between high frequency magnetic anomalies and shallow clinker beds in Utah. High sensitivity aeromagnetic data have been collected in the Collet Top Quadrangle in Kane Country, Utah. The evidence points to the fact that magnetic anomalies are associated with areas of burned coal, that these anomalies can be mapped by airborne surveying and that such mapping can be used to determine the extent of areas within which coal beds are burned and are thus uneconomic.

  20. Nebraska, Kansas, and Oklahoma aeromagnetic and gravity maps and data: a web site for distribution of data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Hill, Patricia L.

    2005-01-01

    The Nebraska, Kansas, and Oklahoma aeromagnetic grid is constructed from grids that combine information collected in 28 separate aeromagnetic surveys conducted between 1954 and 1985. The data from these surveys are of varying quality. The design and specifications (terrain clearance, sampling rates, line spacing, and reduction procedures) varied from survey to survey depending on the purpose of the project and the technology of that time. Every attempt was made to acquire the data in digital form. Most of the available digital data were obtained from aeromagnetic surveys flown by the U.S. Geological Survey (USGS), flown on contract with the USGS, or were obtained from other Federal agencies and State universities. The Kansas data were flown by and acquired from the Kansas Geological Survey. Some of the 1954, 1963, and 1964 data are available only on hand-contoured maps and had to be digitized. These maps were digitized along flight-line/contour-line intersections, which is considered to be the most accurate method of recovering the original data. All surveys have been continued to 304.8 m (1,000 ft) above ground and then blended or merged together.

  1. Patterns of late Cenozoic volcanic and tectonic activity in the West Antarctic rift system revealed by aeromagnetic surveys

    USGS Publications Warehouse

    Behrendt, John C.; Saltus, R.; Damaske, D.; McCafferty, A.; Finn, C.A.; Blankenship, D.; Bell, R.E.

    1996-01-01

    Aeromagnetic surveys, spaced ???5 km, over widely separated areas of the largely ice- and sea-covered West Antarctic rift system, reveal similar patterns of 100- to 1700-nT, shallow-source magnetic anomalies interpreted as evidence of extensive late Cenozoic volcanism. We use the aeromagnetic data to extend the volcanic rift interpretation over West Antarctica starting with anomalies over (1) exposures of highly magnetic, late Cenozoic volcanic rocks several kilometers thick in the McMurdo-Ross Island area and elsewhere; continuing through (2) volcanoes and subvolcanic intrusions directly beneath the Ross Sea continental shelf defined by marine magnetic and seismic reflection data and aeromagnetic data and (3) volcanic structures interpreted beneath the Ross Ice Shelf partly controlled by seismic reflection determinations of seafloor depth to (4) an area of similar magnetic pattern over the West Antarctic Ice Sheet (400 km from the nearest exposed volcanic rock), where interpretations of late Cenozoic volcanic rocks at the base of the ice are controlled in part by radar ice sounding. North trending magnetic rift fabric in the Ross Sea-Ross Ice Shelf and Corridor Aerogeophysics of the Southeast Ross Transect Zone (CASERTZ) areas, revealed by the aeromagnetic surveys, is probably a reactivation of older rift trends (late Mesozoic?) and is superimposed on still older crosscutting structural trends revealed by magnetic terrace maps calculated from horizontal gradient of pseudogravity. Longwavelength (???100-km wide) magnetic terraces from sources within the subvolcanic basement cross the detailed survey areas. One of these extends across the Ross Sea survey from the front of the Transantarctic Mountains with an east-southeast trend crossing the north trending rift fabric. The Ross Sea-Ross Ice Shelf survey area is characterized by highly magnetic northern and southern zones which are separated by magnetically defined faults from a more moderately magnetic central zone

  2. North Dakota aeromagnetic and gravity maps and data, a web site for distribution of data

    USGS Publications Warehouse

    Sweeney, Ronald E.; Hill, Patricia L.

    2003-01-01

    The North Dakota aeromagnetic grid is constructed from grids that combine information collected in 13 separate aeromagnetic surveys conducted between 1978 and 2001. The data from these surveys are of varying quality. The design and specifications (terrain clearance, sampling rates, line spacing, and reduction procedures) varied from survey to survey depending on the purpose of the project and the technology of that time. Every attempt was made to acquire the data in digital form. Most of the available digital data were obtained from aeromagnetic surveys flown by the U.S. Geological Survey (USGS), flown on contract with the USGS, or were obtained from other federal agencies and state universities. Some of the 1980 data are available only on hand-contoured maps and had to be digitized. These maps were digitized along flight-line/contour-line intersections, which is considered to be the most accurate method of recovering the original data. Digitized data are available as USGS Open File Report 99-557. All surveys have been continued to 304.8 meters (1000 feet) above ground and then blended or merged together.

  3. Digital data and derivative products from a high-resolution aeromagnetic survey of the central San Luis basin, covering parts of Alamosa, Conejos, Costilla, and Rio Grande counties, Colorado, and Taos county, New Mexico

    USGS Publications Warehouse

    Bankey, Viki; Grauch, V.J.S.; Webbers, Ank; PRJ, Inc

    2005-01-01

    This report describes data collected from a high-resolution aeromagnetic survey flown over the central San Luis basin during October, 2004, by PRJ, Inc., on contract to the U.S. Geological Survey (USGS). The survey extends from just north of Alamosa, Colorado, southward to just northwest of Taos, New Mexico. It covers large parts of the San Luis Valley in Alamosa, Conejos, Costilla, and Rio Grande Counties, southern Colorado, and the Taos Plateau in Taos County, northern New Mexico. The survey was designed to complement two surveys previously acquired along the eastern borders of the San Luis Basin over the vicinities of Taos, New Mexico (Bankey and others, 2004a) and Blanca, Colorado (Bankey and others, 2004b). Our overall objective in conducting these surveys is to improve knowledge of the subsurface geologic framework in order to understand ground-water systems in populated alluvial basins along the Rio Grande. These USGS efforts are conducted in collaboration with other federal, state, and local governmental entities where possible.

  4. An aeromagnetic survey of Shinmoe-dake volcano, Kirishima, Japan, after the 2011 eruption using an unmanned autonomous helicopter

    NASA Astrophysics Data System (ADS)

    Koyama, Takao; Kaneko, Takayuki; Ohminato, Takao; Yanagisawa, Takatoshi; Watanabe, Atsushi; Takeo, Minoru

    2013-06-01

    In January 2011, magmatic eruptions at Shinmoe-dake, Kirishima, Japan, started for the first time in 300 years. After three sub-plinian explosive events, lava accumulation started at the summit crater. The accumulation lasted for about three months, and the final volume of the accumulated lava reached 1.5 × 107 m3. We conducted aeromagnetic surveys using an unmanned autonomous helicopter over the Shinmoe-dake summit crater in late May 2011, and late October to early November, 2011, in order to investigate the magnetization of this area and changes in the magnetic field associated with the 2011 eruption. The averaged magnetization intensity around Shinmoe-dake is 1.5 A/m. A demagnetized area elongated in the north to northwest direction from Shinmoe-dake has been detected. We also detected a clear change in the total magnetic field between the two aeromagnetic observations characterized by positive and negative changes in the south and north, respectively, of the Shinmoe-dake edifice. These changes are well reproduced by a model in which 20-70% of lava accumulated in the summit crater was cooled down below the Curie temperature and has been magnetized.

  5. Digital aeromagnetic data and derivative products from a helicopter survey over the town of Blanca and surrounding areas, Alamosa and Costilla counties, Colorado

    USGS Publications Warehouse

    Bankey, Viki; Grauch, V.J.S.; ,

    2004-01-01

    This CD-ROM contains digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during a helicopter geophysical survey in southern Colorado during October 2003. The survey covers the town of Blanca and surrounding communities in Alamosa and Costilla Counties. Several derivative products from these data are also presented, including reduced-to-pole, horizontal gradient magnitude, and downward continued grids and images.

  6. Digital Aeromagnetic Data and Derivative Products from a Helicopter Survey over the Town of Taos and Surrounding Areas, Taos County, New Mexico

    USGS Publications Warehouse

    Bankey, Viki; Grauch, V.J.S.; ,

    2004-01-01

    This report contains digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during a helicopter geophysical survey in northern New Mexico during October 2003. The survey covers the Town of Taos, Taos Pueblo, and surrounding communities in Taos County. Several derivative products from these data are also presented, including reduced-to-pole, horizontal gradient magnitude, and downward continued grids and images.

  7. High-Resolution Aeromagnetic Survey To Image Shallow Faults, Poncha Springs and Vicinity, Chaffee County, Colorado

    USGS Publications Warehouse

    Grauch, V.J.S.; Drenth, Benjamin J.

    2009-01-01

    High-resolution aeromagnetic data were acquired over the town of Poncha Springs and areas to the northwest to image faults, especially where they are concealed. Because this area has known hot springs, faults or fault intersections at depth can provide pathways for upward migration of geothermal fluids or concentrate fracturing that enhances permeability. Thus, mapping concealed faults provides a focus for follow-up geothermal studies. Fault interpretation was accomplished by synthesizing interpretative maps derived from several different analytical methods, along with preliminary depth estimates. Faults were interpreted along linear aeromagnetic anomalies and breaks in anomaly patterns. Many linear features correspond to topographic features, such as drainages. A few of these are inferred to be fault-related. The interpreted faults show an overall pattern of criss-crossing fault zones, some of which appear to step over where they cross. Faults mapped by geologists suggest similar crossing patterns in exposed rocks along the mountain front. In low-lying areas, interpreted faults show zones of west-northwest-, north-, and northwest-striking faults that cross ~3 km (~2 mi) west-northwest of the town of Poncha Springs. More easterly striking faults extend east from this juncture. The associated aeromagnetic anomalies are likely caused by magnetic contrasts associated with faulted sediments that are concealed less than 200 m (656 ft) below the valley floor. The faults may involve basement rocks at greater depth as well. A relatively shallow (<300 m or <984 ft), faulted basement block is indicated under basin-fill sediments just north of the hot springs and south of the town of Poncha Springs.

  8. The use of high-resolution aeromagnetic surveys to delineate basement controls on thin-skinned, fractured, tight gas reservoirs: Examples from the Piceance Basin

    SciTech Connect

    Hoak, T.E.; Klawitter, A.L.

    1995-06-01

    An analysis of recently-acquired, high-resolution aeromagnetic data, integrated with structural, production history, and seismic analyses of the Piceance Basin identified a strong correlation between basement structures and fractured tight gas reservoir production trend located in thin-skinned structures. Detailed reservoir characterization of fields associated with Piceance Basin thin-skinned structural traps reveals the importance of fracture-controlled production in these fields. Most importantly, many fields thought to lack fractures, demonstrate insufficient permeability for economic production unless fractures are present. Seismic interpretation indicates that many thin-skinned structures in the Piceance Basin are related to deeper-level basement features. The southwestern basin, in marked contrast, contains E/W-oriented folds such as the Debeque, Bull Creek (new), and Garmesa anticlines. Similar E/W trends are exemplified in the northwest and north-central basin by the Rangely and White River Dome anticlines, respectively. Aeromagnetic surveys, integrated with critical information about regional structure and fractured reservoir production trends, represent a relatively inexpensive method to document potential fractured tight gas reservoirs. In basins where fractured reservoirs are related to small-scale, thin-skinned structures controlled by basement deformation, aeromagnetic surveys permit a rapid first-order screening for potential exploration targets. In mature basins, aeromagnetic surveys may reveal previously-overlooked, small-scale structures containing fracture-controlled production, or overlie deeper reservoir plays not previously tested.

  9. Indian Wells Valley FORGE Aeromagnetic Data

    DOE Data Explorer

    Doug Blankenship

    1994-11-01

    Aeromagnetic data was collected over the Indian Wells Valley, CA in November 1994. It consisted of 9,033 line-kilometers covering ~4,150 square kilometers, flown at a 250 meter drape with principal line spacing of 0.54 kilometers and 10% cross-lines. The principal orientation is N65E.

  10. Distribution of Igneous Rocks in Medina and Uvalde Counties, Texas, as Inferred from Aeromagnetic Data

    USGS Publications Warehouse

    Smith, David V.; McDougal, Robert R.; Smith, Bruce D.; Blome, Charles D.

    2008-01-01

    A high-resolution aeromagnetic survey was flown in 2001 over Medina and Uvalde Counties, Texas, as part of a multi-disciplinary investigation of the geohydrologic framework of the Edwards aquifer in south-central Texas. The objective of the survey was to assist in mapping structural features that influence aquifer recharge and ground-water flow. The survey revealed hundreds of magnetic anomalies associated with igneous rocks that had previously been unmapped. This report presents an interpretation of the outcrops and subcrops of igneous rocks, based upon procedures of matched-filtering and potential field modeling.

  11. Geological interpretation of Landsat TM imagery and aeromagnetic survey data, northern Precordillera region, Argentina

    NASA Astrophysics Data System (ADS)

    Chernicoff, C. J.; Nash, C. R.

    2002-03-01

    This case study demonstrates a methodology for obtaining maximum geoscientific value from reconnaissance (1000 m line spacing) aeromagnetic data through integration with high-resolution satellite imagery. In this study, lithostratigraphic interpretation of optimally processed Landsat TM data at reconnaissance mapping scale (1:100,000) has been carried out as a precursor to geophysical interpretation, providing the basic 'framework' in which to view the imaged geophysical data. The Landsat-derived framework shows the correct positions and vergences of major structures, which characterize this part of the Andean foreland thrust-and-fold belt. Within the structural framework derived from satellite imagery, the locations of major shallow-source aeromagnetic anomalies related to intermediate/mafic extrusive and subvolcanic rocks and the controlling structures of these economically important magmatic events can be correctly interpreted. Results of the study indicate a significant, coherent, and previously unrecognized post-Permian, pre-Miocene volcanic/subvolcanic center, which is probably associated with regional sinistral strike-slip along a reactivated N-S accretionary suture and a pre-existing Precambrian/Paleozoic basement structure. Subsequent west-vergent thick-skinned thrusting associated with uplift of Sierra Valle Fertil Precambrian block has developed a set of distinctive NW-oriented strike-slip faults at the site of the volcanic center. The NW structures cut and rotate late Miocene thin-skinned structures associated with the Precordillera fold-and-thrust belt. Intrusive rocks associated with the inferred Oligocene volcanic center form easily recognizable, partially remanent dipole anomalies, are associated with alteration and Au mineralization (Cerro Guachi, El Pescado, Gnrl. Belgrano mines), and are located along NW-oriented sinistral splay faults. The strike-slip related tectonic/magmatic event is currently regarded as Oligocene in age and may correlate

  12. Aeromagnetics in exploration

    SciTech Connect

    Rasmussen, N.F.

    1983-08-01

    Uses for aeromagnetic surveys include the evaluation of prospect leads and prospects that are controlled by basement fault movements. The identification of basement faults is based on the interpretation of the significance of magnetic edges. Magnetic edges are of two general types: 1) contacts between rock types within the basement, and 2) faults on top of the basement. Traditionally, aeromagnetic surveys have undersampled so that magentic-edge interpretations were not practicable. High resolution aero-magnetic surveys are designed so that basement faulting can be identified and interpreted. Interpretations must be made from magnetic records that have been processed adequately. Many of the magnetic edges which are contacts between different basement lithologies are related to the paleostress fields and are caused by shearing. The identification of the components of the shear models help to explain the orientation of magnetic edges and help to identify the types of basement faults that can be expected. The interpretations are used as working hypotheses for establishing prospects and prospect leads in the overlying sediments.

  13. Aeromagnetic map of parts of Marquette, Dickinson, Baraga, Alger, and Schoolcraft Counties, Michigan, and its geologic interpretation

    USGS Publications Warehouse

    Case, J.E.; Gair, J.E.

    1965-01-01

    The U. S. Geological Survey, in cooperation with the Geological Survey Division of the Michigan Department of Conservation, is conducting a comprehensive restudy of the iron-bearing districts of Michigan. The use of aeromagnetic data is one of the fastest and most reliable methods for outlining the areal distribution of magnetic iron-formation and thus is of material value in assessing the iron resources of the United States. As part of this program of restudy, aeromagnetic surveys of approximately 4,500 square miles of the Northern Peninsula have been made. The results of several of these surveys have been presented by Balsley and others (1949) and by Wier and others (.1953). This report is about a survey made in 1950, over an area of about 1,400 square miles in Marquette County and ad-· joining strips in northern Dickinson and northeastern Baraga Counties, and a later survey flown in 1961, over about 500 square miles in parts of Marquette, Alger, and Schoolcraft Counties. The Marquette iron range extends in an east-west direction across approximately the west-central part of the area, and iron districts of lesser importance are located at Republic, in the southwestern part of the area, and near Gwinn, in the south -central part of the area.Aeromagnetic surveys were flown along north-south lines spaced at intervals of one-quarter mile in the western part of the area and at intervals of from about 1 to 3 miles in the eastern part. Lines were flown at approximately 500 feet above the surface or at elevations of 1,100 to 2,400 feet above sea level. The flight path of the aircraft was recorded by a gyrostabilized continuous-strip camera, and elevation was continuously recorded by a radio altimeter. Magnetic measurements were made by an AN/ASQ-3A fluxgate magnetometer. Compilation of aeromagnetic data was by standard methods, described by Balsley ( 1952 ), under the supervision of John Kirby and Frank Petrafeso. The aeromagnetic contours are relative to an arbitrary

  14. Spectral analysis of the 1976 aeromagnetic survey of Harrat Rahat, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Blank, H. Richard; Sadek, Hamdy S.

    1983-01-01

    Harrat Rahat, an extensive plateau of Cenozoic mafic lava on the Precambrian shield of western Saudi Arabia, has been studied for its water resource and geothermal potential. In support of these investigations, the thickness of the lava sequence at more than 300 points was estimated by spectral analysis of low-level aeromagnetic profiles utilizing the integral Fourier transform of field intensity along overlapping profile segments. The optimum length of segment for analysis was determined to be about 40 km or 600 field samples. Contributions from two discrete magnetic source ensembles could be resolved on almost all spectra computed. The depths to these ensembles correspond closely to the flight height (300 m), and, presumably, to the mean depth to basement near the center of each profile segment. The latter association was confirmed in all three cases where spectral estimates could be directly compared with basement depths measured in drill holes. The maximum thickness estimated for the lava section is 380 m and the mean about 150 m. Data from an isopach map prepared from these results suggest that thickness variations are strongly influenced by pre-harrat, north-northwest-trending topography probably consequent on Cenozoic faulting. The thickest zones show a rough correlation with three axially-disposed volcanic shields.

  15. Tectonic setting of the Portland-Vancouver area, Oregon and Washington: constraints from low-altitude aeromagnetic data

    USGS Publications Warehouse

    Blakely, R.J.; Wells, R.E.; Yelin, T.S.; Madin, I.P.; Beeson, M.H.

    1995-01-01

    Seismic activity in the Portland-Vancouver metropolitan area may be associated with various mapped faults that locally offset volcanic basement of Eocene age and younger. This volcanic basement is concealed in most places by young deposits, vegetation, and urban development. The US Geological Survey conducted an aeromagnetic survey in September 1992 to investigate the extent of these mapped faults and possibly to help identify other seismic and volcanic hazards in the area. The survey was flown approximately 240 m above terrain, along flight lines spaced 460 m apart, and over an area about 50 ?? 50 km. -from Authors

  16. Aeromagnetic anomalies over faulted strata

    USGS Publications Warehouse

    Grauch, V.J.S.; Hudson, Mark R.

    2011-01-01

    High-resolution aeromagnetic surveys are now an industry standard and they commonly detect anomalies that are attributed to faults within sedimentary basins. However, detailed studies identifying geologic sources of magnetic anomalies in sedimentary environments are rare in the literature. Opportunities to study these sources have come from well-exposed sedimentary basins of the Rio Grande rift in New Mexico and Colorado. High-resolution aeromagnetic data from these areas reveal numerous, curvilinear, low-amplitude (2–15 nT at 100-m terrain clearance) anomalies that consistently correspond to intrasedimentary normal faults (Figure 1). Detailed geophysical and rock-property studies provide evidence for the magnetic sources at several exposures of these faults in the central Rio Grande rift (summarized in Grauch and Hudson, 2007, and Hudson et al., 2008). A key result is that the aeromagnetic anomalies arise from the juxtaposition of magnetically differing strata at the faults as opposed to chemical processes acting at the fault zone. The studies also provide (1) guidelines for understanding and estimating the geophysical parameters controlling aeromagnetic anomalies at faulted strata (Grauch and Hudson), and (2) observations on key geologic factors that are favorable for developing similar sedimentary sources of aeromagnetic anomalies elsewhere (Hudson et al.).

  17. Structure of the basement beneath the Illizi Basin: insights from the reinterpretation of an aeromagnetic survey

    NASA Astrophysics Data System (ADS)

    Brahimi, Sonia; Bourmatte, Amar; Ghienne, Jean-François; Munschy, Marc

    2016-04-01

    The Illizi Basin is an intracontinental basin occupying the southeastern part of the Algerian Sahara platform at the northeastern junction of the Hoggar terranes with the East Saharan Metacraton. Aeromagnetic data covering an area of about 2000 km2, including the Illizi Basin, Tassilis and northeastern part of the Hoggar, are compiled to obtain a magnetic map with a special resolution of 600 m and interpreted in the light of that of the adjacent Hoggar Shield, the structural geology of which is well documented. Interpretation of the magnetic map uses potential field transformations like reduction to the pole, fractional vertical derivatives, analytic signal and tilt-depth. These transforms allow to identify beneath the cover of the Illizi Basin two main structural boundaries: 1) The N-S 'Raghane Mega-shear zone' (RSZ) at 8°30 E, manifested by a weak magnetic signal. It corresponds to the most important Panafrican suture, which separates the East Saharan Metacraton from the LATEA terrane assemblage (Metacraton of Central Hoggar). 2) A N-S mega-shear zone at 4°50 E (MSZ4) marked by a strong amplitude anomaly. It separates the Central (LATEA) from the Western Hoggar. Both mega-shear zones change their direction northward: to the NNE for the RSZ and to the NW for the MSZ4. To the west of the RSZ, inside the LATEA, another linear structure is identified by a weak amplitude magnetic lineation, which corresponds to the 7°30 E shear zone (SZ7) marking the western boundary of the Tazat-Assodé-Issalane terranes (TAI). Along SZ7is identified the strongest amplitude magnetic anomaly, which is in excess of 2000 nT and correlated spatially to the northern part of the Ounane pluton. Two other magnetic anomalies further north probably relate to similar bodies. Also a distinct area with strong amplitude magnetic anomalies is identified and extends 300 km toward the north below the sedimentary cover. It is associated to the northern extension of the TAI. In addition, N

  18. Aeromagnetic survey of Dillingham area in southwest Alaska, a website for the preliminary distribution of data

    USGS Publications Warehouse

    U.S. Geological Survey

    2006-01-01

    An airborne high-resolution magnetic survey was completed over the Dillingham and Nushagak Bay and Naknek area in southwestern Alaska. The flying was undertaken by McPhar Geosurveys Ltd. on behalf of the United States Geological Survey (USGS). First tests and calibration flights were completed by August 26th, 2005 and data acquisition was initiated on September 1st, 2005. The final data acquisition flight was completed on October 22nd, 2005. A total of 8,630 line-miles of data were acquired during the survey.

  19. Aeromagnetic surveys in Afghanistan: An updated website for distribution of data

    USGS Publications Warehouse

    Shenwary, Ghulam Sakhi; Kohistany, Abdul Hakim; Hussain, Sardar; Ashan, Said; Mutty, Abdul Salam; Daud, Mohammad Ahmad; Wussow, Michael D.; Sweeney, Ronald E.; Phillips, Jeffrey D.; Lindsay, Charles R.; Kucks, Robert P.; Finn, Carol A.; Drenth, Benjamin J.; Anderson, Eric D.; Abraham, Jared D.; Liang, Robert T.; Jarvis, James L.; Gardner, Joan M.; Childers, Vicki A.; Ball, David C.; Brozena, John M.

    2011-01-01

    Because of its geologic setting, Afghanistan has the potential to contain substantial natural resources. Although valuable mineral deposits and petroleum resources have been identified, much of the country's potential remains unknown. Airborne geophysical surveys are a well accepted and cost effective method for obtaining information about the geological setting of an area without the need to be physically located on the ground. Owing to the current security situation and the large areas of the country that have not been evaluated by geophysical exploration methods, a regional airborne geophysical survey was proposed. Acting upon the request of the Islamic Republic of Afghanistan Ministry of Mines, the U.S. Geological Survey contracted with the Naval Research Laboratory to jointly conduct an airborne geophysical and remote sensing survey of Afghanistan.

  20. Draped aeromagnetic survey in Transantarctic Mountains over the area of the Butcher Ridge igneous complex showing extent of underlying mafic intrusion

    USGS Publications Warehouse

    Behrendt, John C.; Damaske, D.; Finn, C.A.; Kyle, P.; Wilson, T.J.

    2002-01-01

    A draped aeromagnetic survey over the area surrounding the Butcher Ridge igneous complex (BRIC), Transantarctic Mountains, was acquired in 1997-1998 as part of a larger Transantarctic Mountains Aerogeophysical Research Activity survey. The BRIC is a sill-like hypoabyssal intrusion ranging in composition from tholeiitic basalt to rhyolite. An 40Ar/39 Ar age of 174 Ma and the chemical character of the basaltic rocks show the BRIC to be part of the widespread Jurassic Ferrar suite of continental tholeiitic rocks, that extends for 3500 km across Antarctica. The aeromagnetic survey shows a horseshoe-shaped pattern of anomalies reaching amplitudes as great as 1900 nT generally associated with the bedrock topography where it is exposed. It is apparent that the high-amplitude anomaly pattern is more extensive than the 10-km-long exposed outcrop, first crossed by a single 1990 aeromagnetic profile. The highest-amplitude anomalies appear south of the profile acquired in 1990 and extend out of the survey area. The new aeromagnetic data allow determination of the extent of the interpreted Butcher mafic(?) intrusion beneath exposures of Beacon sedimentary rock and ice in the area covered, as well as beneath the small BRIC exposure. The magnetic anomalies show a minimum area of 3000 km2, a much greater extent than previously inferred. Magnetic models indicate a minimum thickness of ???1-2 km for a horizontal intrusion. However, nonunique models with magnetic layers decreasing in apparent susceptibility with depth are consistent with of a 4- to 8-km-thick layered intrusion. These magnetic models indicate progressively deeper erosion of the interpreted mafic-layered body from the south to north. The erosion has removed more magnetic upper layers that mask the magnetic effects of the lower less magnetic layers. The probable minimum volume of the intrusion in the area of the survey is ???6000 km3. An alternate, but less likely, interpretation of a series of dikes can also fit the

  1. Aeromagnetic Survey by Small Unmanned Aerial Vehicle with Magneto-Resistant Magnetometer at the northern Kalgoorlie area, Western Australia

    NASA Astrophysics Data System (ADS)

    Funaki, M.; Group, A.; Milligan, P.

    2006-12-01

    We have developed the technology of small drones (unmanned aerial vehicles (UAV)) and an onboard magnetometer focussed on the aeromagnetic surveys under the Ant-Plane project. We succeeded long distant flight to 500km with agnetometer by Ant-Plene4 drone collaborated with Geoscience, Australia, in March 2006. The survey was carried out in the area 10kmx10km around Mt. Vetters Station, Kalgoorlie, West Australian. The magnetic data are obtained from 41 courses (250m in interval) of EW dierction. The altitude of the flight was 900m from sea level and 500m from the runway. The Ant-Plane #4 consists of 2.6m span and 2.0m length with 2-cycles and 2-cylinder 85cc gasoline engine, GPS navigation system by microcomputer and radio telemeter system. The total weight is 25kg including 12.4 litter fuels and the coursing speed is 130. The magnetometer system consists of a 3-component magneto- resistant magnetometer (MR) sensor (Honeywell HMR2300), GPS and data logger. Three components of magnetic field, latitude, longitude, altitude, the number of satellite and time can be recorded in every second during 6 hours. The sensitivity of the magnetometer is 7 nT and we use a total magnetic field intensity for magnetic analysis due to unknown direction of heading of the plane. MR-magnetometer sensor was installed at the tip of a FRP pipe of 1m length, and the pipe was fixed to the head of the plane in order to reduce the plane magnetization. After 4 hours 14 minutes from the takeoff, the 500km flight was accomplished and the magnetic data were obtained from the data logger. The straight flight course was almost consistent with the way point course, but the course was drastically disturbed when the plane was turning. The magnetic noise level during the flight increased to 30nT, when the plane was flight in the tail wind. However, it is much higher when the plane flew in the head wind. The anomaly pattern obtained from Ant-Plane 4 was compared with the magnetic anomaly map published by

  2. North Slope, Alaska: A case study of Sedimentary AeroMagnetics (SAM)

    SciTech Connect

    McConnell, T.J.

    1995-12-31

    Sedimentary AeroMagnetics (SAM) is the application of very high resolution aeromagnetic data to the exploration for hydrocarbons in the sedimentary section of a basin. Basically SAM provides very high spatial resolution of very low amplitude (<1 nT) anomalies originating from structures within the weakly magnetic sedimentary column. These sedimentary anomalies are superimposed upon the conventional high amplitude magnetic anomalies created by the crystalline basement. These low intensity anomalies generated from within the sediments are related to changes in the magnetic composition of the rocks. This can occur when rocks of differing magnetic susceptibilities are juxtaposed across a fault, or at a stratigraphic truncation. Fluid flow along faults, or at a stratigraphic truncation. Fluid flow along faults and fracture zones can also produce magnetization effects which can allow direct delineament of the fault or fracture zone. Stratigraphic units of weakly magnetic shale and sandstone also create subtle plateau effects in the magnetic amplitude maps. SAM data is a result of combining improvements in aeromagnetic data acquisition technology with new ideas on the design of the survey parameters. SAM surveys are generally flown at 200 - 800 meter line spacing with a terrain clearance of 60 - 150 meters. Data processing techniques are used which preserve the broad band frequency spectrum of the acquired data thereby allowing interpretation of the separate and distinct anomaly sources of the sedimentary column and of the crystalline basement.

  3. Regional interpretation of Kansas aeromagnetic data

    SciTech Connect

    Yarger, H.L.

    1982-01-01

    The aeromagnetic mapping techniques used in a regional aeromagnetic survey of the state are documented and a qualitative regional interpretation of the magnetic basement is presented. Geothermal gradients measured and data from oil well records indicate that geothermal resources in Kansas are of a low-grade nature. However, considerable variation in the gradient is noted statewide within the upper 500 meters of the sedimentary section; this suggests the feasibility of using groundwater for space heating by means of heat pumps.

  4. A Small Autonomous Unmanned Aerial Vehicle, Ant-Plane 4, for aeromagnetic survey

    NASA Astrophysics Data System (ADS)

    Funaki, M.; Tanabe, S.; Project, A.

    2007-05-01

    Autonomous unmanned aerial vehicles (UAV) are expected to use in Antarctica for geophysical research due to economy and safety operations. We have developed the technology of small UAVwith autonomous navigation referred to GPS and onboard magnetometer, meteorolgical devices and digital camera under the Ant-Plane project. The UAV focuses on operation for use in the summer season at coastal area in Antarctica; higher temperature than -15C under calm wind. In case of Ant-Plane 4, it can fly continuously more than 500 km, probably more than 1000 km, although the flight in Antarcitca has not succeeded The UAV of FRP is pusher type drone consisting of 2.6m span and 2.0m length with 2-cycles and 2-cylinder 86cc gasoline engine (7.2 HP) navigated. The maximum takeoff weight is 25kg including 1kg of payload. Cruising distance 500 km at speed of 130 km/h using 10 litter of fuel. The UAV is controlled by radio telemeter within 5km from a ground station and autonomous navigation referred to GPS latitude and longitude, pitot tube speed and barometer altitude. The magnetometer system consists of a 3-component magneto-resistant magnetometer (MR) sensor (Honeywell HMR2300), GPS and data logger. Three components of magnetic field, latitude, longitude, altitude, the number of satellite and time are recorded every second during 6 hours. The sensitivity of the magnetometer is 7 nT and we use a total magnetic field intensity for magnetic analysis due to unknown direction of heading of the plane. We succeeded in long distant flight to 500km with magnetometer by Ant-Plane 4 collaborated with Geoscience Australia, in March 2006. The survey was performed in the area 10kmx10km at Kalgoorlie, Western Australia. The magnetic data are obtained from 41 courses (250m in interval) of EW direction. The altitude of the flight was 900m from sea level and 500m from the runway. MR-magnetometer sensor was installed at the tip of a FRP pipe of 1m length, and the pipe was fixed to the head of the plane

  5. Aeromagnetic maps of the Uinta and Piceance Basins and vicinity, Utah and Colorado

    USGS Publications Warehouse

    Grauch, V.J.S.; Plesha, Joseph L.

    1989-01-01

    In order to understand the evolution of sedimentary basins, it is important to understand their tectonic setting. In a U.S. Geological Survey (USGS) study of the Uinta and Piceance basins in Utah and Colorado, this understanding is approached through characterization of subsurface structure and lithology of a large region encompassing the basins. An important tool for interpreting these subsurface features is aeromagnetic data. Aeromagnetic anomalies represent variations in the strength and direction of the Earth's magnetic field that are produced by rocks containing a significant number of magnetic minerals (commonly magnetite). The shape and magnitude of an anomaly produced by one body of rock are complexly related to the amount of magnetic minerals present, the magnetic properties of those minerals (determined by a number of factors, including the history of the rock), and the shape of the rock body. In the study area, only crystalline basement rocks and volcanic rocks are likely to contain enough magnetic minerals to produce anomalies; sedimentary rocks and metasediments are generally so poor in magnetic minerals that their magnetic effects cannot be detected by the types of surveys presented in this report. Patterns of anomalies on aeromagnetic maps can reveal not only lithologic differences related to magnetite content, but structural features as well, such as faults that have juxtaposed crystalline rocks against sedimentary rocks, and upwarps of crystalline basement underlying sedimentary sequences. Tectonic features of regional extent may not become apparent until a number of aeromagnetic surveys have been compiled and plotted at the same scale. Commonly the compilation involves piecing together data from surveys that were flown at different times and have widely disparate flight specifications and data reduction procedures. The data may be compiled into a composite map, where all the pieces are plotted onto one map without regard to the differences in

  6. Shaded relief aeromagnetic map of the Santa Clara Valley and vicinity, California

    USGS Publications Warehouse

    Roberts, Carter W.; Jachens, Robert C.

    2003-01-01

    This aeromagnetic map covers the southern portion of San Francisco Bay, the Santa Clara Valley and surrounding mountains, part of which has been modelled in threedimensions (Jachens and other, 2001). The magnetic anomaly map has been compiled from existing digital data. Data was obtained from six aeromagnetic surveys that were flown at different times, spacings and elevations. The International Geomagnetic Reference Field (IGRF) for the date of each survey had been removed in the initial processing. The resulting residual magnetic anomalies were analytically continued onto a common surface 305 m (1000 ft) above terrain. Portions of each survey were substantially above the specified flight height listed in the table. The surveys were then merged together using a commercial software package called Oasis Montage. The gray lines on the map indicate the extent of each survey. The program used these regions of overlap to determine the best fit between surveys. Black dots show probable edges of magnetic bodies defined by the maximum horizontal gradient determined using a computer program by Blakely (1995). Crystalline rocks generally contain sufficient magnetic minerals to cause variations in the Earth’s magnetic field that can be mapped by aeromagnetic surveys. Sedimentary rocks are generally weakly magnetized and consequently have a small effect on the magnetic field: thus a magnetic anomaly map can be used to “see through” the sedimentary rock cover and can convey information on lithologic contrasts and structural trends related to the underlying crystalline basement (see Nettleton,1971; Blakely, 1995). Faults often cut magnetic bodies and offset magnetic anomalies can thus be used to help determine fault motion. Serpentinite, which is highly magnetic, is often found along faults. On this map areas of low magnetic anomalies are shown in blues and green while highs are shown in reds and magentas. Faults are from Brabb and others, 1998a,1998b, Graymer and others

  7. New dense-grid aeromagnetic map of Gulf of Guinea cul-de-sac, northeastern equatorial Atlantic Ocean

    SciTech Connect

    Babalola, O.O.

    1985-02-01

    As part of a major project to procure miscellaneous geophysical coverage of the entire country, the Geological Survey of Nigeria has acquired aeromagnetic data, presented as contour maps at various scales, over the nation's 7 sedimentary basins. The coverage over the Nigerian continental margin, acquired at 2500 ft above sea level, was flown at 4-km flight-line spacing in a north-northeasterly direction and at 20-km tie-line spacing in a west-northwesterly direction. Another tie line was flown along the coastline. Twenty 1:250,000 one-degree square, total intensity aeromagnetic contour maps covering the marginal basins down to the shelf break were assembled into a single aeromagnetic map of the Gulf of Guinea cul-desac. The map area lies within lat. 3/sup 0/-8/sup 0/N, and long. 2/sup 0/-9/sup 0/E. It covers the Nigerian portion of the Dahomey embayment, the Anambra and Niger delta basins, and the southern portion of the Benue rift. The map covers the location of the postulated Late Cretaceous triple junction involving the Benue Trough aulacogen, the northward-propagating South Atlantic, and the transform-dominated Equatorial Atlantic. In addition to the region seaward of the continental shelf, the map covers the Niger Delta basin, the basement of which is also inferred to consist mainly of oceanic crust prograded by the thick sediments of the Tertiary Niger delta. This areas is also the location of the Late Cretaceous coalescence of the North Atlantic and South Atlantic spreading systems hitherto separate from one another. This new aeromagnetic map fills an important data gap (due to proprietary restrictions and acquisition difficulties) in previous studies of this oil-prolific and geologically unique province. The map would be useful in future structural and tectonics studies of the Gulf of Guinea cul-de-sac.

  8. Aeromagnetic maps of the Colorado River region including the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degrees quadrangles, California, Arizona, and Nevada

    USGS Publications Warehouse

    Mariano, John; Grauch, V.J.

    1988-01-01

    Aeromagnetic anomalies are produced by variations in the strength and direction of the magnetic field of rocks that include magnetic minerals, commonly magnetite. Patterns of anomalies on aeromagnetic maps can reveal structures - for example, faults which have juxtaposed magnetic rocks against non-magnetic rocks, or areas of alteration where magnetic minerals have been destroyed by hydrothermal activity. Tectonic features of regional extent may not become apparent until a number of aeromagnetic surveys have been compiled and plotted at the same scale. Commonly the compilation involves piecing together data from surveys that were flown at different times with widely disparate flight specifications and data reduction procedures. The data may be compiled into a composite map, where all the pieces are plotted onto one map without regard to the difference in flight elevation and datum, or they may be compiled into a merged map, where all survey data are analytically reduced to a common flight elevation and datum, and then digitally merged at the survey boundaries. The composite map retains the original resolution of all the survey data, but computer methods to enhance regional features crossing the survey boundaries may not be applied. On the other hand, computer methods can be applied to the merged data, but the accuracy of the data may be slightly diminished.

  9. Aeromagnetic data workshop

    NASA Astrophysics Data System (ADS)

    Clark, David M.; Hittelman, Allen M.

    A workshop on aeromagnetic data, sponsored by the National Geophysical Data Center (NGDC) of the National Oceanic and Atmospheric Administration, was held in Boulder, Colo., November 16-18, 1982, to evaluate the requirements for a national aeromagnetic database. The following recommendations were developed by J . R. Heirtzler, Woods Hole Oceanographic Institution; W. J. Hinze, Purdue University; A. M. Hittelman, ARCO Exploration Company; K. Svendsen, CIRES, University of Colorado; D. M. Clark, National Geophysical Data Center; T. M, Anderson, Union Oil of California; and P. Ochsner and R. Van Nieuwenhuise, Cities Service.1. A national aeromagnetic anomaly data file of available digital data and a central distribution center are urgently needed in the United States.

  10. Aeromagnetic signatures reveal a back-arc basin imposed upon the inherited rifted margin of the East Antarctic craton

    NASA Astrophysics Data System (ADS)

    Armadillo, E.; Ferraccioli, F.; Jordan, T. A.; Bozzo, E.

    2009-12-01

    The Wilkes Subglacial Basin (WSB) represents a largely unexplored, approximately 1400 km-long and up to 600 km-wide subglacial depression, buried beneath the over 3 km-thick East Antarctic Ice Sheet. During the 2005-06 austral summer an extensive aerogeophysical survey was flown to investigate the WSB adjacent to northern Victoria Land (NVL), and included the acquisition of new airborne radar, aeromagnetic and aerogravity data. Several contrasting models for the origin of the basin have been previously proposed, and are based primarily on relatively sparse gravity data. These range from Cenozoic flexure, to distributed crustal extension of unknown age (possibly Mesozoic to Cenozoic), and even compression along the margin of craton. Our recent aeromagnetic data reveal that the basin is structurally controlled and has a tectonic origin, at least adjacent to NVL. The eastern margin of the basin is imposed upon an Early Paleozoic thrust fault belt, which can be traced under the ice using aeromagnetic signatures from exposures in Oates Land and the Ross Sea coast. Aeromagnetic patterns reveal that the western margin of the basin is imposed upon a Proterozoic-age shear zone mapped in the Mertz Glacier, and that is interpreted from geological studies to represent the continuation of a coeval shear zone in Australia. The broad aeromagnetic and satellite magnetic low over the WSB contrasts with the high over the un-reworked Proterozoic craton to the west of the basin, and is interpreted to reflect Neoproterozoic-age sediments deposited along the rifted margin of the craton. Magnetic intrusions within the WSB are interpreted as back-arc plutons that formed later in response to Cambrian-Ordovician age subduction along the paleo-Pacific margin of Gondwana. The aeromagnetic interpretation for a former broad back-arc basin in the WSB is supported by the occurrence of low-grade metasedimentary rocks of back-arc affinity in Oates Land, and also by the similarity in long

  11. Investigation of an aeromagnetic anomaly on west side of Yucca Mountain, Nye County, Nevada

    SciTech Connect

    Bath, G.D.; Jahren, C.E.

    1985-12-31

    Investigations of the source of a prominent aeromagnetic anomaly of 290 nT were undertaken at a potential repository site located in the Yucca Mountain area, Nevada Test Site. The anomaly was detected on a recent flight line of a survey flown north-south at 400 m (1300 ft) spacing and 122 m (400 ft) above the surface. The anomaly was not detected on older lines flown east-west at the same spacing and altitude above the surface. The anomaly, which is on the high-standing side of a major fault, was interpreted previously as arising from either an increase of magnetization within a volcanic tuff or a small intrusive feature. Ground magnetic traverses were run to locate the ground maximum, and to delineate anomalies in a traverse that crosses the ground maximum and the nearby fault. Both air and ground anomalies were analyzed using geologic data from surface mapping and drill holes, and magnetic property data from drill holes. The anomaly is caused by contributions from at least three sources. The elevated topography gives a terrain effect since the altitude is decreased between the airplane and exposed Topopah Spring Member of the Paintbrush Tuff. Ground anomalies 300 m (1000 ft) south of the air maximum indicate either an increase in magnetization or the presence of a small intrusive body. Finally, there is an increase in magnetic influence from the nearby Solitario Canyon fault. 16 refs., 10 figs., 5 tabs.

  12. Profiles of gamma-ray and magnetic data from aerial surveys over the conterminous United States

    USGS Publications Warehouse

    Duval, Joseph S.; Riggle, Frederic E.

    1999-01-01

    This publication contains images for the conterminous U.S. generated from geophysical data, software for displaying and analyzing the images, and software for displaying and examining the profile data from the aerial surveys flown as part of the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy. The images included are of gamma-ray data (uranium, thorium, and potassium channels), Bouguer gravity data, isostatic residual gravity data, aeromagnetic anomalies, topography, and topography with bathymetry.

  13. Using high-resolution aeromagnetic survey to map tectonic elements of plate boundaries: An example from the Dead Sea Fault

    NASA Astrophysics Data System (ADS)

    Al-Zoubi, A. S.; ten Brink, U. S.; Rybakov, M.; Rotstein, Y.

    2004-12-01

    The Dead Sea Fault (DSF) is a transform plate boundary between the African and the Arabian plates. The 200-km-long DSF segment between the Gulf of Aqaba/Elat and the Dead Sea, which has the morphology of a rift valley, shows little seismic activity, and its surface trace is only intermittently visible. High-resolution magnetic data were collected in October 2003 aboard a Jordanian military helicopter flying at an altitude of 100 m over the southern 120-km-long section of this fault segment. The survey was part of a US-AID Middle Eastern Regional Cooperation project between Jordanian, Israeli, Palestinian, and American scientists. Data were collected along rift-perpendicular lines spaced 300 m apart, requiring frequent crossings between Israeli and Jordanian air spaces. The data were gridded at 75 m interval following resolution tests, reduced to pole, and incorporated into a GIS together with elevation, geology, and gravity maps to facilitate interpretation. The main findings of the magnetic survey are the absence of magnetic anomalies crossing the rift valley, and the presence of a rift-parallel regional lineament corresponding to the active trace of the DSF. The lineament extends NNE as an almost continuous trace from Elat, Israel, to the eastern side of the valley 5 km north of Rahmeh. Jordan. Another fault trace located 2-3 km to the west may overlap and continue NNE through Gebel A-Risha, and into the central Arava/Araba valley, where it is visible on the surface. Alternatively, the two traces may be connected. If an offset between the two traces exists, it may be small enough to allow an earthquake rupture to propagate across the offset, and generate an earthquake with a moment magnitude of up to 7.5. Traces of buried faults in the central Arava/Araba valley that were previously active in the DSF system, are visible as abrupt terminations of an area of short wavelength magnetic anomalies. These anomalies probably represent shallow subsurface magmatic

  14. Aeromagnetic exploration over the East Antarctic Ice Sheet: A new view of the Wilkes Subglacial Basin

    NASA Astrophysics Data System (ADS)

    Ferraccioli, Fausto; Armadillo, Egidio; Jordan, Tom; Bozzo, Emanuele; Corr, Hugh

    2009-12-01

    The Wilkes Subglacial Basin represents an approximately 1400 km-long and up to 600 km wide subglacial depression, buried beneath the over 3 km-thick East Antarctic Ice Sheet. Contrasting models, including rift models and flexural models, have been previously put forward to explain the tectonic origin of this enigmatic basin, which is located in the largely unexplored hinterland of the Transantarctic Mountains. A major aerogeophysical survey was flown during the 2005-06 austral summer to explore the Wilkes Subglacial Basin. Our new airborne radar dataset reveals that the Wilkes Subglacial Basin contains several subglacial basins, which are considerably deeper than previously mapped. Major aeromagnetic lineaments are detected from total field, pseudo-gravity, tilt derivative and Euler Deconvolution maps. These aeromagnetic lineaments reveal that the Wilkes Subglacial Basin and its sub-basins are structurally controlled. Comparison between aeromagnetic signatures over the Wilkes Subglacial Basin region and the Cordillera in North America, suggests that the basin contains a former broad backarc basin and fold-and-thrust belts, forming the transition between a Precambrian craton and the Ross Orogen. The eastern margin of the Wilkes Subglacial Basin is imposed upon the Prince Albert Fault System and the Priestley Fault. These faults may have been reactivated in the Cenozoic, as major strike-slip faults. The western margin of the Wilkes Subglacial Basin is located along the southern extension of the Precambrian-age Mertz Shear Zone and marks the edge of the Terre Adélie Craton. High-frequency aeromagnetic anomalies in the Wilkes Subglacial Basin image large volumes of Jurassic tholeiites, which were intruded into and extruded over Beacon sediments in a possible rift setting. Depth-estimates of magnetic anomaly sources and forward modelling indicate that major Cretaceous and Cenozoic rift basins with thick sedimentary infill, comparable to the deep Ross Sea Rift basins

  15. Unique Aeromagnetic-radar Ice-sounding Survey over the West Antarctic Ice Sheet Allows Three Dimensional Definition of Sources of Magnetic Anomalies Caused by Subglacial Volcanic Sources at the Bed of the Ice

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.; Casertz; Soar Teams

    2011-12-01

    The West Antarctic Ice Sheet (WAIS) flows through the volcanically active West Antarctic Rift System (WARS). The aeromagnetic method has proven the most useful geophysical tool for studying subglacial volcanic rocks beneath the WAIS since early surveys in the 1950s. The Central West Antarctica (CWA) aerogeophysical survey covering ~354,000 km2 (about the area of Nevada and California combined) over the WAIS, consisting of a 5-km line-spaced, orthogonal set of aeromagnetic, radar ice-sounding and aerogravity measurements, is a unique Antarctic data set. This 1990-97 survey (CASERTZ and SOAR), still provides invaluable information on subglacial volcanic rocks, particularly when combined with widely spaced older aeromagnetic flight lines over a much greater area. These combined survey data indicate numerous high-amplitude (100->1000 nT), 5-50 km width, shallow-source, magnetic anomalies over a very extensive area (>1.2 x 106 km2) mostly resulting from subglacial volcanic eruptions. I interpreted the anomalies sampled in the CWA survey as defining ~1000 "volcanic centers" requiring high remanent normal magnetizations in the present field direction. About 400 of these anomaly sources (conservatively selected) are correlated with bed topography. The tops of >80% of these anomaly sources have <200 m relief at the bed of the WAIS. They appear modified by moving ice, requiring a younger age than the WAIS (~25 Ma). The 5 km by 5 km orthogonal flight line survey obviated aliasing of the magnetic and radar ice sounding data, because it is approximately equivalent to the flight elevation above the ice (1 km) surface plus the ice thickness (2-3 km); it reveals the magnetic anomalies and the tops of volcanic sources at its bed in three dimensions. Models (2 1/2 D) fit to a number of the magnetic anomalies, whose sources are at the bed of the ice sheet are constrained by topography measured by the radar ice sounding. Volcanoes in the WARS are <34 Ma, but at least four are active

  16. Aeromagnetic and gravity data over the Central Transantarctic Mountains (CTAM), Antarctica: a website for the distribution of data and maps

    USGS Publications Warehouse

    Anderson, E.D.; Finn, C.A.; Damaske, D.; Abraham, J.D.; Goldmann, F.; Goodge, J.W.; Braddock, P.

    2006-01-01

    Near complete coverage of the East Antarctic Shield by ice hampers geological study of crustal architecture important for understanding global tectonic and climate history. Limited exposures in the central Transantarctic Mountains (CTAM), however, show that Archean and Proterozoic rocks of the shield as well as Neoproterozoic-lower Paleozoic sedimentary successions were involved in oblique convergence associated with Gondwana amalgamation. Subsequently, the area was overprinted by Jurassic magmatism and Cenozoic uplift. To extend the known geology of the region to ice-covered areas, we conducted an aeromagnetic survey flown in draped mode by helicopters over the Central Transantarctic Mountains and by fixed-wing aircraft over the adjacent polar plateau. We flew more than 32,000 line km covering an area of nearly 60,000 km2 at an average altitude of 600 m, with average line spacing 2.5 km over most areas and 1.25 km over basement rocks exposed in the Miller and Geologists ranges. Additional lines flown to the north, south, and west extended preliminary coverage and tied with existing surveys. Gravity data was collected on the ground along a central transect of the helicopter survey area.

  17. Werner deconvolution for variable altitude aeromagnetic data

    SciTech Connect

    Ostrowski, J.S. ); Pilkington, M.; Teskey, D.J. )

    1993-10-01

    The standard Werner deconvolution method is extended to include the effects of variable sensor altitude but this leads to a deconvolution algorithm that is unstable for slowly changing flight height. By expressing the sensor altitude as a linear function of horizontal position (within a specified window), the authors show that the numerical instability can be avoided. The subsequent selection and averaging of the raw solutions is controlled by three parameters that can be adjusted to specific survey data characteristics. Results for an aeromagnetic survey over Vancouver Island, British Columbia show that, in comparison with the variable altitude approach, the standard Werner method produces unacceptable errors when applied to variable altitude data.

  18. Optical filtering of aeromagnetic maps.

    PubMed

    Arsenault, H H; Séguin, M K; Brousseau, N

    1974-05-01

    An optical processor has been used to filter aeromagnetic contour maps in order to obtain information on underground magnetic ore deposits. This was accomplished by directional filtering of the spatial Fourier transform of the contour map. The directional filtering yields maps of gradients having given directions. A digital analysis was also performed on the data so that the feasibility of the optical technique could be evaluated. The results obtained so far suggest that a systematic filtering of aeromagnetic maps can be carried out at low cost and that the filtered maps can yield useful information to the interpreter.

  19. Aeromagnetic map of Korea; Magnetic patterns and structural features

    NASA Astrophysics Data System (ADS)

    Park, Yeong-Sue; Rim, Hyoungrea; Lim, Mutaek; Shin, Young Hong

    2014-05-01

    Regional airborne magnetic survey is very cost-effective mapping tool. Magnetic anomaly maps have abundant information, which are an important tool for understanding the geological evolution and mineral exploration. The pattern of magnetic anomaly map is a powerful indicator of geologic structure and rock formation. Magnetic anomaly patterns primarily reflect the distribution and structural setting of magnetized material within the crust. These features including amplitude and orientation of individual anomalies or the texture of anomalous regions can provide useful constraints for geological interpretation. KIGAM has conducted airborne magnetic mapping programme since 1982, and has coverage of almost whole the country. The latest version of airborne magnetic anomaly map was published by compiling data acquired from 1982 to 2012. The helicopter-borne surveys were flown by a line spacing 1~2 km with control lines of 5~8 km. The flight altitude was tried to keep 100~150 m above ground surface with sampling distance of 30m. The data were continued to the reference level of 300 m above ground level, and regional field was reduced by 11th generation IGRF. This paper introduced the latest version of magnetic anomaly map of Korea, and briefly examined the magnetic characteristics, with geologic characteristics and structural features of tectonic zones. Furthermore, magnetic patterns were quantitatively analyzed by using skeletonization technique. Korea, southern part of the Korean peninsula, could be divided in 5 tectonic provinces, such as, Gyeonggi massif, Okcheon fold belt, Sobaeksan massif, Gyeongsang basin, and circum-Pacific alkali volcanic zone. Magnetic anomalies in Gyeonggi massif zone are broadly distributed with moderately high amplitude, and the dominant trend is NE, but not strong. Okcheon fold belt can be magnetically characterized as strong dominant NE trend (Sinian direction) and linear positive anomalies of high amplitude. Sobaeksan massif is magnetically

  20. Aeromagnetic map and selected aeroradiometric data for the Ellicott Rock Wilderness and additions, South Carolina, North Carolina, and Georgia

    USGS Publications Warehouse

    Luce, Robert W.; Daniels, David L.

    1985-01-01

    The aeromagnetic and aeroradiometric data presented herin for the Ellicott Rock Wilderness and additions are taken from an airborne survey that covered a larger area in Georgia, North Carolina and South Carolina, and that was flown in December 1980 and January 1981 under contract to the U.S. Geological Survey. The flight lines were oriented northwest-southeast, approximately perpendicular to the general strike of the geology, at 0.5-mi (0.8-km) separation and at a nominal altitude of 500 ft (150 m) above mean terrain. A small amount of areomagnetic data from previous survey (Riggle and others, 1980) along the southeast edge of the study area is based on east-west flight lines spaced 1 mi (1.6 km) apart. Because of the rugged topography in the region, holding the airplane at a constant elevation abive the terrain was not possible. Actual ground clearance over short distances ranged between about 200 and 1200 ft. The International Geomagnetic Reference Field (IGRF) has been removed from the magnetic data (Barraclough and Fabiano, 1975) and 5000 gammas were added to make all values positive. 

  1. CASERTZ aeromagnetic data reveal late Cenozoic flood basalts (?) in the West Antarctic rift system

    USGS Publications Warehouse

    Behrendt, John C.

    1994-01-01

    The late Cenozoic volcanic and tectonic activity of the enigmatic West Antarctic rift system, the least understood of the great active continental rifts, has been suggested to be plume driven. In 1991-1992, as part of the CASERTZ (Corridor Aerogeophysics of the Southeast Ross Transect Zone) program, an ~25 000 km aeromagnetic survey over the ice-covered Byrd subglacial basin shows magnetic "texture' critical to interpretations of the underlying extended volcanic terrane. The aeromagnetic data reveal numerous semicircular anomalies ~100-1100 nT in amplitude, interpreted as having volcanic sources at the base of the ice sheet; they are concentrated along north-trending magnetic lineations interpreted as rift fabric. The CASERTZ aeromagnetic results, combined with >100 000 km of widely spaced aeromagnetic profiles, indicate at least 106 km3 of probable late Cenozoic volcanic rock (flood basalt?) in the West Antarctic rift beneath the ice sheet and Ross Ice Shelf. -from Authors

  2. US Aeromagnetic and Satellite Magnetic Anomaly Comparisons

    NASA Technical Reports Server (NTRS)

    Vonfrese, R. R. B.; Hinze, W. J.; Braile, L. W. (Principal Investigator); Sexton, J. L.

    1984-01-01

    Scalar aeromagnetic data obtained by the U.S. Naval Oceanographic Office (NOO) Vector Magnetic Survey of the conterminous U.S. were screened for periods of intense diurnal magnetic activity and reduced to anomaly form, filtered, and continued upward. A number of correlations between the NOO, POGO and preliminary MAGSAT data are evident at satellite elevations, including a prominent transcontinental magnetic high which extends from the Anadarko Basin to the Cincinnati Arch. The transcontinental magnetic high is breached by negative anomalies located over the Rio Grande Rift and Mississippi River Aulacogen. Differentially reduced-to-pole NOO and POGO magnetic anomaly data show that the transcontinental magnetic high corresponds to a well-defined regional trend of negative free-air gravity and enhanced crustal thickness anomalies.

  3. Preliminary aeromagnetic anomaly map of California

    USGS Publications Warehouse

    Roberts, Carter W.; Jachens, Rober C.

    1999-01-01

    The magnetization in crustal rocks is the vector sum of induced in minerals by the Earth’s present main field and the remanent magnetization of minerals susceptible to magnetization (chiefly magnetite) (Blakely, 1995). The direction of remanent magnetization acquired during the rock’s history can be highly variable. Crystalline rocks generally contain sufficient magnetic minerals to cause variations in the Earth’s magnetic field that can be mapped by aeromagnetic surveys. Sedimentary rocks are generally weakly magnetized and consequently have a small effect on the magnetic field: thus a magnetic anomaly map can be used to “see through” the sedimentary rock cover and can convey information on lithologic contrasts and structural trends related to the underlying crystalline basement (see Nettleton,1971; Blakely, 1995). The magnetic anomaly map (fig. 2) provides a synoptic view of major anomalies and contributes to our understanding of the tectonic development of California. Reference fields, that approximate the Earth’s main (core) field, have been subtracted from the recorded magnetic data. The resulting map of the total magnetic anomalies exhibits anomaly patterns related to the distribution of magnetized crustal rocks at depths shallower than the Curie point isotherm (the surface within the Earth beneath which temperatures are so high that rocks lose their magnetic properties). The magnetic anomaly map has been compiled from existing digital data. Data obtained from aeromagnetic surveys that were made at different times, spacings and elevations, were merged by analytical continuation of each set onto a common surface 305 m (1000 ft) above terrain. Digital data in this compatible form allows application of analytical techniques (Blakley, 1995) that can be used to enhance anomaly characteristics (e.g., wavelength and trends) and provide new interpretive information.

  4. Aeromagnetic survey of Howard Pass quadrangle and the East half of Misheguk Mountain quadrangle, Alaska—a Web site for the distribution of data

    USGS Publications Warehouse

    Brown, Philip J.

    2009-01-01

    U.S. Geological Survey Open-File-Report 2009-1256 is for the preliminary release of magnetic data (and associated contractor reports) for an airborne survey in the Brooks Range, northwest of Bettles, Alaska.

  5. Integrated interpretation of high-resolution aeromagnetic data with high-frequency seismic and Landsat data - Northwest Williston basin

    SciTech Connect

    Andrew J.A.; Graf, R.J.; O'Brien, D.P.; Wold, R.J.

    1986-08-01

    A low-altitude (300-ft), close-spaced (4 lines/mi) airborne magnetic gradiometer survey was flown in a 1000-mi/sup 2/ area of northeastern Montana. This area included 31 oil fields, and a modern high-frequency, broad-bandwidth seismic data set was obtained across it. The aeromagnetic survey was designed specifically to study and analyze the short-wavelength, small-amplitude magnetic anomalies associated with near-surface magnetic sources. A secondary objective was a more conventional magnetic basement study. Some of the near-surface magnetic sources may be related to epigenetic changes associated with seepage from hydrocarbon reservoirs. All 31 oil fields displayed a near-surface magnetic anomaly. Other near-surface magnetic anomalies displayed an obvious seismic anomaly visible on the high-frequency, broad-bandwidth seismic data. In addition, the zones that offset and truncate the observed near-surface magnetic anomalies can be seen in the seismic data. This suggests a small, though deep-seated, Quaternary or Holocene wrench-fault system. Many of the magnetic offset zones were also visible in available Landsat data. Some magnetically observed basement faults were also visible on the seismic and Landsat data.

  6. Recent Aeromagnetic Anomaly views of the Antarctic continent

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.

    2012-04-01

    Antarctica is a keystone within the Gondwana and Rodinia supercontinents. However, despite intense geological research along the coastal fringes of Antarctica, the interior of the continent remains one of the most poorly understood regions on Earth. Aeromagnetic investigations are a useful tool to help disclose the structure and the evolution of continents from the Precambrian to the Cenozoic and Antarctica is no exception. Here I review a variety of aeromagnetic studies in East and West Antarctica performed since the completion of the first generation ADMAP -Antarctic Digital Magnetic Anomaly Project- in 2001. In western Dronning Maud, in East Antarctica, aeromagnetic data help delineate the extent of the Jurassic Jutulstraumen subglacial rift that is flanked by remnants of a Grenvillian-age (ca 1.1. Ga) igneous province and magmatic arc. Different magnetic signatures appear to characterize the Coats Land block but reconnaissance surveys are insufficient to fully delineate the extent and significance of the Coats Land block, a possible tectonic tracer of Laurentia within Rodinia (Loewy et al., 2011). Further in the interior of East Antarctica, a mosaic of distinct and hitherto largely unknown Precambrian provinces has recently been revealed by combining aeromagnetic and satellite magnetic data with models of crustal thickness constrained by gravity modeling and seismology (Ferraccioli et al., 2011, Nature). A major collisional suture may lie between the Archean Ruker Province and an inferred Proterozoic Gamburtsev Province but the age of final assembly of central East Antarctica remains uncertain and controversial. I favour a Grenville-age collisional event (linked to Rodinia assembly) or possibly older Paleoproteroic collision, followed by intraplate reactivation, as opposed to Neoproterozoic or Early Cambrian collision linked to East-West Gondwana assembly (Boger, 2011). New aerogeophysical surveys over Prince Elizabeth and Queen Mary Land could test this

  7. Geology and Mineral Resources of the North Absaroka Wilderness and Vicinity, Park County, Wyoming, with Sections on Mineralization of the Sunlight Mining Region and Geology and Mineralization of the Cooke City Mining District, and a Section on Aeromagnetic Survey

    USGS Publications Warehouse

    Nelson, Willis H.; Prostka, Harold J.; Williams, Frank E.; Elliott, James E.; Peterson, Donald L.

    1980-01-01

    SUMMARY The North Absaroka Wilderness is approximately 560 square miles (1,450 km 2 ) of rugged scenic mountainous terrain that adjoins the eastern boundary of Yellowstone National Park in northwestern Wyoming. The area was studied during 1970, 1971, and 1972 by personnel of the U. S. Geological Survey and the U. S. Bureau of Mines to evaluate its mineral-resource potential as required by the Wilderness Act of 1964. This evaluation is based on a search of the literature courthouse and production records, geologic field mapping, field inspection of claims and prospects, analyses of bedrock and stream-sediment samples, and an aeromagnetic survey. The North Absaroka Wilderness is underlain almost entirely by andesitic and basaltic volcanic rocks of Eocene age. These volcanics rest on deformed sedimentary rocks of Paleozoic and, locally, of Mesozoic age that are exposed at places along the northern and eastern edges of the wilderness. Dikes and other igneous intrusive bodies cut both the volcanic and sedimentary rocks. A nearly flat detachment fault, the Heart Mountain fault, and a related steep break-away fault have displaced middle and upper Paleozoic rocks and some of the older part of the volcanic sequence to the southeast. A much greater thickness of volcanic rocks was found to be involved in Heart Mountain faulting than had previously been recognized; however, most of the volcanic rocks and many of the intrusives were emplaced after Heart Mountain faulting. Local folding and high-angle faulting in mid-Eocene time have deformed all but the youngest part of the volcanic sequence in the southeastern part of the wilderness. This deformation is interpreted as the last pulse of Laramide orogeny. The results of this study indicate that the mineral-resource potential of the wilderness is minimal. Bentonite, petroleum, low-quality coal, and localized deposits of uranium and chromite have been produced in the surrounding region from rocks that underlie the volcanic rocks

  8. Gravity, aeromagnetic and rock-property data of the central California Coast Ranges

    USGS Publications Warehouse

    Langenheim, V.E.

    2014-01-01

    Gravity, aeromagnetic, and rock-property data were collected to support geologic-mapping, water-resource, and seismic-hazard studies for the central California Coast Ranges. These data are combined with existing data to provide gravity, aeromagnetic, and physical-property datasets for this region. The gravity dataset consists of approximately 18,000 measurements. The aeromagnetic dataset consists of total-field anomaly values from several detailed surveys that have been merged and gridded at an interval of 200 m. The physical property dataset consists of approximately 800 density measurements and 1,100 magnetic-susceptibility measurements from rock samples, in addition to previously published borehole gravity surveys from Santa Maria Basin, density logs from Salinas Valley, and intensities of natural remanent magnetization.

  9. Terrane Definition From Textural Measures of Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Gettings, M.

    2007-12-01

    The vertical and horizontal magnetization in the Earth's crust is an anisotropic multifractal distribution, and this results in a horizontal multifractal distribution of magnetic anomalies at and above the Earth's surface. Discreet lithologic terranes are frequently observed to exhibit a characteristic pattern or "texture" of anomalies in aeromagnetic maps. Multifractal measures provide some tools useful in quantifying different textures and the scaling properties of aeromagnetic anomalies in map view can be used to define boundaries between terranes of different magnetic textures. If the source depths are not too large, the magnetic textural measures of lithologic units can be used to map their extent beneath cover. Although magnetic anomaly textures are generally visible to the eye on aeromagnetic anomaly images, the actual boundary between two textures is frequently difficult to determine with certainty. The use of quantitative textural measures provides a more objective framework for the boundary definition problem. A high resolution aeromagnetic survey over an area of highly variable geology has been used as a test area for these studies. Two robust measures that have proven useful for textural analysis are: the number of extrema per unit area; and the surface area per unit area in a window moving over the gridded aeromagnetic data. The former measures the "noisiness" of the data, and the latter depends on anomaly amplitudes and discriminates between large and small magnetizations. Window sizes for texture analysis are typically a few km square because geologic terranes of interest are generally of the order of tens of km in characteristic dimension. Other measures investigated are based on the scaling properties of the field within the window computed from the structure function for various exponents. The minima of the structure function define the characteristic sizes of anomalies, analogous to the power spectrum for a periodic function, and the maxima

  10. Project MAGNET High-level Vector Survey Data Reduction

    NASA Technical Reports Server (NTRS)

    Coleman, Rachel J.

    1992-01-01

    Since 1951, the U.S. Navy, under its Project MAGNET program, has been continuously collecting vector aeromagnetic survey data to support the U.S. Defense Mapping Agency's world magnetic and charting program. During this forty-year period, a variety of survey platforms and instrumentation configurations have been used. The current Project MAGNET survey platform is a Navy Orion RP-3D aircraft which has been specially modified and specially equipped with a redundant suite of navigational positioning, attitude, and magnetic sensors. A review of the survey data collection procedures and calibration and editing techniques applied to the data generated by this suite of instrumentation will be presented. Among the topics covered will be the determination of its parameters from the low-level calibration maneuvers flown over geomagnetic observatories.

  11. Aeromagnetic map compilation: Procedures for merging and an example from Washington

    USGS Publications Warehouse

    Finn, C.

    1999-01-01

    Rocks in Antarctica and offshore have widely diverse magnetic properties. Consequently, aeromagnetic data collected there can improve knowledge of the geologic, tectonic and geothermal characteristics of the region. Aeromagnetic data can map concealed structures such as faults, folds and dikes, ascertain basin thickness and locate buried volcanic, as well as some intrusive and metamorphic rocks. Gridded, composite data sets allow a view of continental-scale trends that individual data sets do not provide and link widely-separated areas of outcrop and disparate geologic studies. Individual magnetic surveys must be processed so that they match adjacent surveys prior to merging. A consistent representation of the Earth's magnetic field (International Geomagnetic Reference Field (IGRF)) must be removed from each data set. All data sets need to be analytically continued to the same flight elevation with their datums shifted to match adjacent data. I advocate minimal processing to best represent the individual surveys in the merged compilation. An example of a compilation of aeromagnetic surveys from Washington illustrates the utility of aeromagnetic maps for providing synoptic views of regional tectonic features.

  12. Question of Ages of Cenozoic Volcanic Centers Inferred Beneath the West Antarctic Ice Sheet (WAIS) in the West Antarctic Rift System (WR) from Coincident Aeromagnetic and Radar Ice Sounding Surveys

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.; Finn, C. A.; Blankenship, D. D.

    2007-12-01

    The recently acquired radar ice sounding surveys (Holt, et al., 2006) extending the 1990s Central West Antarctica (CWA) aerogeophysical survey to the Amundsen and Bellingshausen sea coasts allows us to revise a thought experiment reported by Behrendt et al., 1991 from very limited bed elevation data. Were the ice of the WAIS flowing through the WR to be compressed to the density of crustal rock, almost all of the area beneath the WAIS would be at or above sea level, much >1 km elevation. There are only about 10-20% of the very deep areas (such as the Bentley subglacial trench and the Byrd Subglacial Basin) filled with 3-4-km thick ice that would be well below sea level. The age of the 5-7-km high rift shoulder bounding the asymmetric WR from northern Victoria Land through the Horlick Mountains (where it diverges from the Transantarctic Mountains) to the Ellsworth Mountains has been reported as old as Cretaceous. Volcanic exposures associated with the West Antarctic rift system in the present WAIS area extend at least to 34 Ma and the West Antarctic ice sheet has flowed through the rift possibly as far back in time as 25 Ma. Active volcanism has been reported for the WR at only a few widely scattered locations, so speculations about present volcanic activity beneath the WAIS are quite uncertain, and it is probably quite rare. The Central West Antarctic aeromagnetic and radar ice sounding survey carried out in the 1990s revealed about 1000 "volcanic centers" characterized by 100-1000 nT shallow source magnetic anomalies, at least 400 of which have associated bed topography. About 80% of these show relief <200 m and have been interpreted as smoothed off as they were erupted (injected) into the moving WAIS. Several kilometer-thick highly magnetic sources are required to fit these anomalies requiring high remanent magnetizations in the present field direction. We interpreted these sources as subvolcanic intrusions which must be younger than about 100 Ma because the

  13. Composite materials flown on the Long Duration Exposure Facility

    NASA Technical Reports Server (NTRS)

    George, Pete E.; Dursch, Harry W.; Pippin, H. Gary

    1995-01-01

    Organic composite test specimens were flown on several LDEF experiments. Both bare and coated composites were flown. Atomic oxygen eroded bare composite material, with the resins being recessed at a greater rate than the fibers. Selected coating techniques protected the composite substrate in each case. Tensile and optical properties are reported for numerous specimens. Fiberglass and metal matrix composites were also flown.

  14. Aeromagnetic data and geological structure of continental China: A review

    NASA Astrophysics Data System (ADS)

    Xiong, Sheng-Qing; Tong, Jing; Ding, Yan-Yun; Li, Zhan-Kui

    2016-06-01

    We review the latest aeromagnetic geological data of continental China. We discuss the latest achievements in geological mapping and the newly detected features based on aeromagnetic data. Using aeromagnetic data collected for more than 50 years, a series of 1:5000000 and 1:1000000 aeromagnetic maps of continental China were compiled using state-of-the-art digital technology, and data processing and transformation. Guided by plate tectonics and continental dynamics, rock physical properties, and magnetic anomalies, we compiled maps of the depth of the magnetic basement of continental China and the major geotectonic units, and presented newly detected geological structures based on the aeromagnetic data.

  15. High-resolution aeromagnetics: cost-effective reconnaissance tool for mature provinces

    SciTech Connect

    Rascoe, B.; Czimer, W.J.

    1987-08-01

    Petroleum exploration in a mature province must be continually monitored in terms of the risk-reward ratio (finding costs versus potential field size). Over much of the Mid-Continent where lower Paleozoic reservoirs have provided prolific reserves in structural traps for 75 years, the search for an ever-shrinking number of these accumulations seems to require deploying expensive seismic grids. High-resolution aeromagnetic surveys provide a low-cost means of identifying anomalies in the basement complex of the type associated with productive, basement-controlled structural features. High-resolution aeromagnetics uses the Vacquier method to identify the edges of magnetic bodies on flight-line profiles. Through this method, the interpreter recognizes signatures on the profile that indicate faults in the basement complex and their sense of throw. Structural anomalies are generally less than 10 ..gamma..; compositional changes commonly differ by a greater order of magnitude. The successful use of a high-resolution aeromagnetic survey depends on the evaluation of the basement anomalies through geologic analysis of associated structural and thickness patterns. The final step is a seismic program to confirm the existence of the aeromag-subsurface prospects and to select drill sites. At current prices, the cost of a high-resolution aeromagnetic survey over a township area (36 mi/sup 2/ or 93 km/sup 2/) is approximately equivalent to the cost of 2 mi of proprietary seismic data. Thus, in terms not only of use, but more importantly cost, high-resolution aeromagnetics is a reconnaissance tool that can significantly lower finding costs in a mature productive province.

  16. An interpretation of the 1996 aeromagnetic data for the Santa Cruz basin, Tumacacori Mountains, Santa Rita Mountains, and Patagonia Mountains, south-central Arizona

    USGS Publications Warehouse

    Gettings, Mark E.

    2002-01-01

    High resolution aeromagnetic survey data flown at 250 m above the terrain and 250 m line spacing over the Santa Cruz Valley and the surrounding Tumacacori, Patagonia, and Santa Rita Mountains has been interpreted by correlation of the magnetic anomaly field and various derivative maps with geologic maps. Measurements of in-situ magnetic properties of several of the map units determined whether or not mapped lithologies were responsible for observed anomalies. Correlation of the magnetic anomaly field with mapped geology shows that numerous map units of volcanic and intrusive rocks from Jurassic Middle Tertiary in age are reversely polarized, some of which have not been previously reported. Trends derived from the magnetic anomaly data correlate closely with structures from major tectonic events in the geologic history of the area including Triassic-Jurassic crustal accretion and magmatism, Laramide magmatism and tectonism, northeast-southwest Mid-Tertiary extension, and east-west Basin and Range extension. Application of two textural measures to the magnetic anomaly data, number of peaks and troughs per km (a measure of roughness) and Euclidean length per km (a measure of amplitude), delineated areas of consistent magnetic anomaly texture. These measures were successful at the delineation of areas of consistent magnetic lithology both on the surface and in the subsurface beneath basin fill. Several areas of basement prospective for mineral resources beneath basin fill were identified.

  17. Mapping paleostructures from time-related aeromagnetic lineaments and photolineaments

    SciTech Connect

    Peterson, R.M.

    1985-01-01

    A classification of aeromagnetic lineaments has been adapted for use with photolineaments. William Dean Gibbons recently defined sets of structurally-high, aeromagnetic lineaments for each Phanerozoic period; e.g., N19/sup 0/W and N71/sup 0/E for Cambrian time. This model was tested on several Cambrian (Knox) oil fields in Kentucky by mapping dense sets of N34/sup 0/W, N19/sup 0/W, N86/sup 0/E, and N71/sup 0/E lineaments from air photos and interpreting drag folds from lineaments. A comparison of Knox structural contour maps with Cambrian drag fold maps indicates that drag fold maps approximate structural contour maps; clusters of N19/sup 0/W and N71/sup 0/E drag folds correspond to closed highs. Several porosity and permeability trends were identified for Cambrian and Ordovician reservoirs. This procedure for mapping paleohighs has been further tested in the Mid-Continent on structures that range in age from Cambrian to Cretaceous and is being used (with Landsat) to identify locations of paleostructures that range in age from Cambrian to Cretaceous and is being used (with Landsat) to identify locations of paleostructures for seismic surveys. With air photos the method is used for detailed studies on fracture, porosity/permeability trends and delineation of features identified first on Landsat. A current project in the Denver-Julesburg basin, using Landsat RBV images, in the search for new Pennsylvanian and Permian paleohighs.

  18. Aeromagnetic Expression of Buried Basaltic Volcanoes Near Yucca Mountain, Nevada

    USGS Publications Warehouse

    O'Leary, D. W.; Mankinen, E.A.; Blakely, R.J.; Langenheim, V.E.; Ponce, D.A.

    2002-01-01

    A high-resolution aeromagnetic survey has defined a number of small dipolar anomalies indicating the presence of magnetic bodies buried beneath the surface of Crater Flat and the Amargosa Desert. Results of potential-field modeling indicate that isolated, small-volume, highly magnetic bodies embedded within the alluvial deposits of both areas produce the anomalies. Their physical characteristics and the fact that they tend to be aligned along major structural trends provide strong support for the hypothesis that the anomalies reflect buried basaltic volcanic centers. Other, similar anomalies are identified as possible targets for further investigation. High-resolution gravity and ground-magnetic surveys, perhaps along with drilling sources of selected anomalies and radiometric age determinations, can provide valuable constraints in estimating potential volcanic hazard to the potential nuclear waste repository at Yucca Mountain.

  19. Aeromagnetic interpretation and mineral investigations in the Bolu, Canakkale-Karabiga, Demirkoy, Ezine, and Orhaneli areas of northwestern Turkey in 1968

    USGS Publications Warehouse

    Jacobson, Herbert Samuel; Tumer, Ural; Karahacioglu, Hamit

    1972-01-01

    This report reviews progress made during 1968 in the continuing Joint Haden Tetkik ve Arama Enstitusu (MSA)-U. S. Geological Survey (USGS) Mineral Exploration and Training Project, Subproject 2. Subproject 2 is concerned with aeromagnetic interpretation of MTA's aeromagnetic surveys, and ground investigations of selected aeromagnetic anomalies. This report includes new aeromagnetic maps for the Bolu, Canakkale-Karabiga, Demirkoy, and Orhaneli areas and reviews ground investigations in five areas. Activities for each area are sunmarized below: 1. Bolu area: The aeromagnetic map shows two belts of anomalies related to regional magnetite-bearing formations and a group of discrete anomalies, some of which may reflect significant concentrations of magnetite. To date three of these anomalies have been checked on the ground and at one a metamorphic rock containing 14 percent magnetite was observed. 2. Canakkale-Karabiga area: Ground checks were made of six aeromagnetic anomalies. At one locality (Cakirly-Koyu) 6 km south of Nazmara Sea a small magnetite deposit was found. The magnetic anomaly over the area is 150 meters long, and about 3 meters deep in the center of the anomaly exposed massive magnetite boulders. 3. Demirkoy area: The aeromagnetic map shows only one significant anomaly which was checked on the ground and found to be caused by minor magnetite at an intrusive contact. 4. Ezine area: A ground survey of 4.5 sq km area was made where magnetite boulders are locally present on the surface. No significant magnetic anomaly or iron mineralization were found. 5. Orhaneli area: The aeromagnetic map o# the area showed regional magnetic anomaly patterns related to magnetite in mafic intrusives, ultramafic rocks, and mafic flow rocks. In addition 16 localized anomalies were identified. Most of these anomalies were checked on the ground but no significant iron deposits were found. The largest deposit found was a one-meter wide magnetite vein. During the 1969 field season

  20. Interpretation of magnetic surveys in intermontane valleys of Nevada and southern New Mexico

    USGS Publications Warehouse

    Bath, G.D.

    1976-01-01

    An evaluation of the magnetic method of geophysical exploration in intermontane valleys is made through examples of magnetic properties, magnetic surveys, reduction of data, and analysis of magnetic anomalies from some valley areas. Measurements of magnetic properties of samples collected along valley margins or from drill holes indicate that the anomaly-producing rocks are mostly Tertiary volcanic flows in Nevada and mostly Cretaceous-Tertiary intrusives in southern New Mexico. Aeromagnetic data were compiled as both observed and residual anomalies from surveys at various flight-line spacings and intervals from ground surface. Theoretical anomalies from known models were analyzed to recover data on depth, width, and magnetization of models and thereby establish reliability of methods used by certain investigators. These methods were then applied to measured anomalies to obtain information about the igneous rock structures that are buried beneath nonmagnetic valley alluvium. Recommendations made for future valley studies include aeromagnetic surveys flown 150 m above ground surface and at 800 m spacing; measurement of magnetic properties from outcrop samples, drill-core samples, and magnetometer logging of uncased drill holes; and use of the interpretation from gravity surveys in the same area.

  1. 14 CFR 91.181 - Course to be flown.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Course to be flown. 91.181 Section 91.181 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC... § 91.181 Course to be flown. Unless otherwise authorized by ATC, no person may operate an...

  2. 14 CFR 91.181 - Course to be flown.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Course to be flown. 91.181 Section 91.181 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC... § 91.181 Course to be flown. Unless otherwise authorized by ATC, no person may operate an...

  3. 14 CFR 91.181 - Course to be flown.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Course to be flown. 91.181 Section 91.181 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC... § 91.181 Course to be flown. Unless otherwise authorized by ATC, no person may operate an...

  4. Aeromagnetic, gravity anomaly, and derivative maps of the Craig and Dixon Entrance 1-degree by 3-degree quadrangles of southeastern Alaska

    USGS Publications Warehouse

    Wynn, Jeffrey C.; Kucks, R.P.; Grybeck, D.J.

    1999-01-01

    This CD-ROM contains aeromagnetic, gravity, geology, and topographic data as well as several derivative products, for the Craig and Dixon Entrance 1? ? 3? quadrangles of Southeastern Alaska. The data were collected by the U.S. Geological Survey directly and by means of several contract airborne surveys, through August 1991.

  5. Geologic and aeromagnetic maps of the Fossil Ridge area and vicinity, Gunnison County, Colorado

    USGS Publications Warehouse

    DeWitt, Ed; Zech, R.S.; Chase, C.G.; Zartman, R.E.; Kucks, R.P.; Bartelson, Bruce; Rosenlund, G.C.; Earley, Drummond

    2002-01-01

    This data set includes a GIS geologic map database of an Early Proterozoic metavolcanic and metasedimentary terrane extensively intruded by Early and Middle Proterozoic granitic plutons. Laramide to Tertiary deformation and intrusion of felsic plutons have created numerous small mineral deposits that are described in the tables and are shown on the figures in the accompanying text pamphlet. Also included in the pamphlet are numerous chemical analyses of igneous and meta-igneous bodies of all ages in tables and in summary geochemical diagrams. The text pamphlet also contains a detailed description of map units and discussions of the aeromagnetic survey, igneous and metmorphic rocks, and mineral deposits. The printed map sheet and browse graphic pdf file include the aeromagnetic map of the study area, as well as figures and photographs. Purpose: This GIS geologic map database is provided to facilitate the presentation and analysis of earth-science data for this region of Colorado. This digital map database may be displayed at any scale or projection. However, the geologic data in this coverage are not intended for use at a scale other than 1:30,000. Supplemental useful data accompanying the database are extensive geochemical and mineral deposits data, as well as an aeromagnetic map.

  6. Preliminary aeromagnetic map of the Nevada Test Site and vicinity, Nevada

    SciTech Connect

    Kirchoff-Stein, K.S.; Ponce, D.A.; Chuchel, B.A.

    1989-12-31

    As part of an effort to help geologically characterize a possible high-level nuclear waste repository at Yucca Mountain, a merged aeromagnetic map of the Nevada Test Site (NTS) and vicinity was prepared from eight separate aeromagnetic surveys. Each data set was compiled and merged by Kucks and Hildenbrand (1987) as part of a statewide aeromagnetic map of Nevada (Hildenbrand and Kucks, 1988). During processing each data set was gridded at a 1-km interval, and a geomagnetic reference field was removed. Prior to merging, each grid was either upward or downward continued to 1000 ft above the ground and datum shifts were applied, where necessary, to achieve an overall constant datum. The resulting map yields an integrated picture of the total magnetic field that is useful for identifying areas of further interest and for qualitative interpretation. However, quantitative interpretation should be made using the original data, because anomaly locations and relative amplitudes may have been altered slightly during computer processing. The final merged map was compared with the individual published maps to ensure that the location of major anomalies and magnetic trends were preserved. The average difference in anomaly positions for major anomalies is about 0.4 km, which is reasonable for a 1-km grid spacing. 13 refs.

  7. Preliminary geologic interpretation of aeromagnetic data in the Yakutat district, Alaska

    USGS Publications Warehouse

    Johnson, Gordon R.; Plafker, George

    1969-01-01

    An aeromagnetic survey covering portions of the Yakutat Feveland region in south-central Alaska was made to delineate concentrations of magnetic minerals possibly associated with heavy mineral placers in beach sands and raised beach ridges. However, the larger magnetic anomalies do not correlate with the beach placers in the surveyed area. The dominant magnetic feature, a strong linear positive anomaly almost parallel to the coastline, is thought to reflect a bedrock feature, probably a mafic igneous body enclosed within nonmagnetic rocks of the Yakutat group.

  8. The Cottage Lake Aeromagnetic Lineament: A Possible Onshore Extension of the Southern Whidbey Island Fault, Washington

    USGS Publications Warehouse

    Blakely, Richard J.; Sherrod, Brian L.; Wells, Ray E.; Weaver, Craig S.; McCormack, David H.; Troost, Kathy G.; Haugerud, Ralph A.

    2004-01-01

    The northwest-striking southern Whidbey Island fault zone (SWIF) was mapped previously using borehole data and potential-field anomalies on Whidbey Island and marine seismic surveys beneath surrounding waterways. Abrupt subsidence at a coastal marsh on south-central Whidbey Island suggests that the SWIF experienced a MW 6.5 to 7.0 earthquake about 3000 years ago. Southeast of Whidbey Island, a hypothesized southeastward projection of the SWIF would make landfall between the cities of Seattle and Everett. As part of systematic, ongoing studies by the U.S. Geological Survey, University of Washington, and other earth science organizations to evaluate potentially active faults and other earth hazards throughout the Puget Lowland, we test this hypothesis using aeromagnetic, lidar, and borehole data. Linear, northwest-striking magnetic anomalies traversing the mainland region project southeastward toward the communities of Woodinville and Maltby, Washington. All of these magnetic anomalies are low in amplitude and best illuminated in residual magnetic fields. The most prominent of the residual magnetic anomalies extends at least 16 km, lies approximately on strike with the SWIF on Whidbey Island, and passes near Crystal and Cottage Lakes, about 27 km southeast of downtown Everett. In places, this magnetic anomaly is associated with topographic lineaments, but spectral analysis indicates that the source of the anomaly extends to depths greater than 2 km and cannot be explained entirely by topographic effects. The Alderwood #1 oil exploration well located on strike with the Cottage Lake aeromagnetic lineament shows evidence of deformation over a total depth range of 3000 m; some beds within this interval exhibit intense fracturing and shearing, although deformation within the well can only be constrained as post-early Oligocene and pre-Pleistocene. Boreholes acquired as part of a wastewater tunnel project show evidence of soil disturbance at locations where some

  9. Utility of aeromagnetic studies for mapping of potentially active faults in two forearc basins: Puget Sound, Washington, and Cook Inlet, Alaska

    USGS Publications Warehouse

    Saltus, R.W.; Blakely, R.J.; Haeussler, P.J.; Wells, R.E.

    2005-01-01

    High-resolution aeromagnetic surveys over forearc basins can detect faults and folds in weakly magnetized sediments, thus providing geologic constraints on tectonic evolution and improved understanding of seismic hazards in convergent-margin settings. Puget Sound, Washington, and Cook Inlet, Alaska, provide two case histories. In each lowland region, shallow-source magnetic anomalies are related to active folds and/or faults. Mapping these structures is critical for understanding seismic hazards that face the urban regions of Seattle, Washington, and Anchorage, Alaska. Similarities in aeromagnetic anomaly patterns and magnetic stratigraphy between the two regions suggest that we can expect the aeromagnetic method to yield useful structural information that may contribute to earth-hazard and energy resource investigations in other forearc basins.

  10. Aeromagnetic map of the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    Ponce, D.A.; Blakely, R.J.

    2002-03-12

    This aeromagnetic map of the Death Valley ground-water model area was prepared from numerous separate aeromagnetic surveys that were gridded, merged, and described by Hildenbrand and Kucks (1988) and by McCafferty and Grauch (1997). These data are available in grid format from the EROS Data Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, and from the National Geophysical Data Center, 325 Broadway, E/GC4, Boulder, Colo., 80303. Magnetic investigations of the Death Valley ground-water basin are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency Agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwest Nevada and adjacent parts of California (Blakely and others, 2000b). The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W.

  11. Aeromagnetics, Geology and the Geoscience Database for Africa

    NASA Astrophysics Data System (ADS)

    Reeves, Colin

    2010-05-01

    The process of systematic geological mapping of Africa, as established in the first half of the twentieth century, involved heroic periods of field mapping by individuals on single map sheets, supported eventually by interpretation of aerial photography, with the publication of colour maps and reports on paper as the ultimate aim. Despite the advent of satellite imagery in the 1970s, this activity trailed off in the final decades of the century. This was partly due to political changes in Africa but also due to the growing realization that the amount of outcrop available for examination is little to none over great swathes of the continent. Estimates indicate that less than half the sheets that cover the continent had been mapped by about the year 2000, and only half of those mapped had actually reached publication stage. Even then, ‘publication' often meant only that paper copies could be purchased from the sales office of a national geological survey, of which there are more than 50. The second half of the century saw the growing realization that aeromagnetic surveys (that effectively ‘saw through' weathering and widespread sedimentary veneers) could accelerate the geological mapping process and provide useful geological reconnaissance of large areas - typically whole African countries - in years rather than decades. With, in some cases, the support of international aid agencies, airborne geophysical programmes have been launched across Africa and, in some countries, re-launched with greater detail as airborne survey technology continuously improved with time. The advent of gamma-ray spectrometry of high resolution delivered a powerful additional tool after about 1990. It is certain that several hundred million dollars have now been invested in programmes of this type across Africa. It is argued that much of the value of this work has still to be realized. The extraction of geological information from airborne geophysical surveys involves the application of

  12. GEOTEAM{reg_sign}/aeromagnetic definition of hydrocarbon alteration plumes in Nevada

    SciTech Connect

    Rowe, J.D.; Smith, R.S.; Warren, R.K.

    1994-12-31

    An airborne electromagnetic and magnetic survey was flown over a number of oil fields in Nevada to map alteration plumes. In some of the areas, there is an anomalous magnetic response and an excellent correlation between an enhanced conductivity anomaly and the oil fields. The approach indicates that alteration plumes may be detected and defined with greater confidence employing a multi-sensor survey than with only a single sensor system (e.g., magnetics only).

  13. High-resolution aeromagnetics as an exploration tool in the Timor Sea, northwestern Australia

    SciTech Connect

    O'Brien, G.W.; Wellman, P. )

    1991-03-01

    The Mesozoic Vulcan Graben in the Timor Sea, northwestern Australia, is one of Australia's most active oil exploration areas, with a number of discoveries made within the last five years. To further assist in understanding the structural setting of the region, the Australian Bureau of Mineral Resources (BMR) carried out a regional high-resolution aeromagnetic survey over the Vulcan Graben in late 1989. Three to twelve km wavelength, 0.2-2.0 nT amplitude magnetic anomalies have northeast strikes and correlate well with the position and orientation of the rift faults, as defined by seismic reflection data. Significantly, the magnetic trends closely match the fault trends at the prospective Valanginian unconformity horizon, where all of the major producing reservoirs are located. Numerous northwest-trending (strike-slip ) faults have also been mapped as zones of low anomaly, some of which correspond with offsets in the major northeast-trending anomalies. These faults, which are probably due to the reactivation of either Mesozoic transfer faults or Paleozoic normal faults, may have a major role in the entrapment of hydrocarbons in the Timor Sea, as most producing fields are located close to a northwest-trending fault or its extension. The northwest-trending faults have not previously been defined using seismic data. This survey shows that even in an area with extensive seismic coverage such as the Timor Sea, high-resolution aeromagnetics can provide important information that both complements and supplements the seismic data.

  14. Aeromagnetic anomalies and perspective oil traps in China

    SciTech Connect

    Zhang, Y.X. )

    1994-10-01

    Based on analyses of aeromagnetic data from known oil and gas fields in China, aeromagnetic anomalies have been classified according to their genesis into three types: (1) structure-associated anomalies related to volcanic rocks, (2) anomalies related to magnetic basement fault blocks, and (3) structure-associated anomalies related to weakly magnetic sedimentary strata. The most successful applications of aeromagnetic data for locating favorable oil and gas structures are in the following kinds of areas: (1) areas where basement fault blocks of inhomogeneous lithology and magnetization are developed; (2) areas of weakly magnetic layered strata with a considerably thickness, either effusive or clastic deposits; and (3) areas where magnetic layers have undergone tectonic deformation with faulting and dip angles larger than 30 degrees. For reliable detection of such structures in sedimentary rocks and associated oil and gas traps, an integrated interpretation of geological and geophysical data is necessary.

  15. Peeking below Columbia River flood basalts with high-resolution aeromagnetic data: implications for central Washington earthquake hazards

    NASA Astrophysics Data System (ADS)

    Blakely, R. J.; Sherrod, B. L.; Wells, R. E.; Weaver, C. S.

    2012-12-01

    The largest crustal earthquake in Washington's recorded history (M 6.8) occurred in 1872 in the vicinity of Lake Chelan. Numerous smaller earthquakes (>1000 earthquakes since 1971 with 1.0 ≤ MW ≤ 4.3) continue to occur 20 km south of Lake Chelan near the town of Entiat, yet little is known about active structures responsible for this ongoing deformation. A 2011 aeromagnetic survey may provide insights. The survey was flown with a fixed-wing aircraft along flight lines spaced 400 m apart and at an altitude 250 m above terrain or as low as safely possible. The survey illuminates two distinct magnetic patterns. Northwest of Entiat, broad, subdued magnetic anomalies are caused by weakly magnetic, pre-Tertiary basement rocks striking generally NW. Magnetic lineaments are associated, for example, with the NW-striking Entiat fault, the structural margin of the Chiwaukum graben, which is well represented by gravity anomalies. Southeast of Entiat, high-amplitude, short-wavelength magnetic anomalies are caused by strongly magnetic rocks of the Miocene Columbia River Basalt Group (CRBG) exposed throughout this region. Northwest-striking basement anomalies, so clear NW of Entiat, are not obvious SE of Entiat, yet there is no reason to believe basement structures do not extend beneath CRBG. We used matched filtering methods to illuminate the crustal framework of the Entiat earthquakes beneath CRBG. We selected two sub regions, one over pre-Tertiary basement NW of Entiat (sub region 1), the other over CRBG SE of Entiat (sub region 2). We modeled each sub region by fitting layer parameters to power spectra determined from magnetic anomalies (Phillips, 2007). A strongly magnetic layer was determined 470 m below the aircraft in sub region 2, which we interpret as the average top of CRBG. This interpretation is supported by the absence of a similar magnetic layer in sub region 1, where CRBG is in fact absent. Using this determination, we designed a matched filter to subdue

  16. Aeromagnetic interpretation of southwestern continental shelf of Korea

    SciTech Connect

    Baag, Czango; Baag, C.E.

    1996-12-31

    Analysis of the {open_quotes}project magnet{close_quotes} aeromagnetic data acquired by the US Navy in 1969 permits us to predict a new sedimentary basin, Heugsan Basin, south of the known Gunsan Basin in Block II. The basin appears to consist of three sub-basins trending NNW-SSE. The results of our analysis provide not only an independent assessment of the Gunsan Basin, but also new important information on the tectonic origin and mechanism for the two basins as well as for the entire region. The basin forming tectonic style is interpreted as rhombochasm associated with double overstepped left-lateral wrench faults. From magnetic evidence, a few NE-SW trending major onshore faults are extended to the study area. We also interpreted the nature of the faults to be left-lateral wrenches. This new gross structural style is consistent with the results of recent Yeongdong Basin analysis by Lee. The senses of fault movement are also supported by the paleomagnetic evidence that the Philippine Sea had experienced an 80-degree clockwise rotation since the Eocene. Based on a 2{1/2} - D model study the probable maximum thickness of the sediments in the Gunsan Basin is approximately 7500 meters. We believe that the new Heugsan Basin was left unidentified because a high velocity layer may be overlying the basin. Because the overall structural configuration of the Heugsan Basin appears to be favorable for hydrocarbon accumulation, a detailed airborne magnetic survey is recommended in the area in order to verify the magnetic expressions of both this thick basin and the tectonic style.

  17. Aeromagnetic interpretation of southwestern continental shelf of Korea

    SciTech Connect

    Baag, Czango ); Baag, C.E. )

    1996-01-01

    Analysis of the [open quotes]project magnet[close quotes] aeromagnetic data acquired by the US Navy in 1969 permits us to predict a new sedimentary basin, Heugsan Basin, south of the known Gunsan Basin in Block II. The basin appears to consist of three sub-basins trending NNW-SSE. The results of our analysis provide not only an independent assessment of the Gunsan Basin, but also new important information on the tectonic origin and mechanism for the two basins as well as for the entire region. The basin forming tectonic style is interpreted as rhombochasm associated with double overstepped left-lateral wrench faults. From magnetic evidence, a few NE-SW trending major onshore faults are extended to the study area. We also interpreted the nature of the faults to be left-lateral wrenches. This new gross structural style is consistent with the results of recent Yeongdong Basin analysis by Lee. The senses of fault movement are also supported by the paleomagnetic evidence that the Philippine Sea had experienced an 80-degree clockwise rotation since the Eocene. Based on a 2[1/2] - D model study the probable maximum thickness of the sediments in the Gunsan Basin is approximately 7500 meters. We believe that the new Heugsan Basin was left unidentified because a high velocity layer may be overlying the basin. Because the overall structural configuration of the Heugsan Basin appears to be favorable for hydrocarbon accumulation, a detailed airborne magnetic survey is recommended in the area in order to verify the magnetic expressions of both this thick basin and the tectonic style.

  18. Regional Geothermal Characterisation of East Anatolia from Aeromagnetic, Heat Flow and Gravity Data

    NASA Astrophysics Data System (ADS)

    Bektaş, Özcan; Ravat, Dhananjay; Büyüksaraç, Aydin; Bilim, Funda; Ateş, Abdullah

    2007-05-01

    East Anatolia is a region of high topography made up of a 2-km high plateau and Neogene and Quaternary volcanics overlying the subduction-accretion complex formed by the process of collision. The aeromagnetic and gravity data surveyed by the Mineral Research and Exploration (MTA) of Turkey have been used to interpret qualitatively the characteristics of the near-surface geology of the region. The residual aeromagnetic data were low-pass filtered and analyzed to produce the estimates of magnetic bottom using the centroid method and by forward modelling of spectra to evaluate the uncertainties in such estimates. The magnetic bottom estimates can be indicative of temperatures in the crust because magnetic minerals lose their spontaneous magnetization at the Curie temperature of the dominant magnetic minerals in the rocks and, thus, also are called Curie point depths (CPDs). The Curie point depths over the region of Eastern Anatolia vary from 12.9 to 22.6 km. Depths computed from forward modelling of spectra with 200 600 km window sizes suggest that the bottom depths from East Anatolia from the magnetic data may have errors exceeding 5 km; however, most of the obtained depths appear to lie in the above range and indicate that the lower crust is either demagnetized or non-magnetic. In the interpretation of the magnetic map, we also used reduction-to-pole (RTP) and amplitude of total gradient of high-pass filtered anomalies, which reduced dipolar orientation effects of induced aeromagnetic anomalies. However, the features of the RTP and the total gradient of the high-pass filtered aeromagnetic anomalies are not highly correlated to the hot spring water locations. On the other hand, many high-amplitude features seen on the total gradient map can be correlated with the ophiolitic rocks observed on the surface. This interpretation is supported by Bouguer gravity data. In this paper, we recommend that the sources of the widespread thermal activity seen in East Anatolia must

  19. Aeromagnetic and aeromagnetic-based geologic maps of the Coastal Belt, Franciscan Complex, northern California

    USGS Publications Warehouse

    Langenheim, V.E.; Jachens, R.C.; McLaughlin, R.J.

    2011-01-01

    The Coastal belt of the Franciscan Complex represents a Late Cretaceous to Miocene accretionary prism and overlying slope deposits. Its equivalents may extend from the offshore outer borderland of southern California to north of the Mendocino Triple Junction under the Eel River Basin and in the offshore of Cascadia. The Coastal belt is exposed on land in northern California, yet its structure and stratigraphy are incompletely known because of discontinuous exposure, structural disruption, and lithologically non-distinctive clastic rocks. The intent of this report is to make available, in map form, aeromagnetic data covering the Coastal belt that provide a new dataset to aid in mapping, understanding, and interpreting the incompletely understood geology and structure in northern California. The newly merged aeromagnetic data over the Coastal belt of the Franciscan Complex reveal long, linear anomalies that indicate remarkably coherent structure within a terrane where mapping at the surface indicates complex deformation and that has been described as "broken formation" and, even locally as "melange". The anomalies in the Coastal belt are primarily sourced by volcanic-rich graywackes and exotic blocks of basalt. Some anomalies along the contact of the Coastal belt with the Central belt are likely caused by local interleaving of components of the Coast Ranges ophiolite. These data can be used to map additional exotic blocks within the Coastal belt and to distinguish lithologically indistinct graywackes within the Coastal terrane. Using anomaly asymmetry allows projection of these "layers" into the subsurface. This analysis indicates predominant northeast dips consistent with tectonic interleaving of blocks within a subduction zone.

  20. Aeromagnetic interpretation and mineral investigations in the Ezine, Canakkale-Karabiga, Marmara, and Kapidag areas of northwestern Turkey

    USGS Publications Warehouse

    Jacobson, Herbert Samuel; Ozelci, F.; Yazgan, Durmaz; Hatay, N.; Karahacioglu, Hamit

    1972-01-01

    Aeromagnetic surveys and mineral investigations are planned or in progress in ten areas of northwestern Turkey (fig. 1). This report reviews results obtained from August 1967 to January 1, 1968, through aeromagnetic interpretation and field investigations in four of the areas (Areas 2, 3,4, and 5). Aeromagnetic interpretation identified 27 prominent anomalies, 17 of which were checked in the field. The majority of these anomalies were found to be caused by minor amounts of magnetite in igneous rocks, including granite stocks, mafic flows, and mafic dikes. Other anomalies are caused by magnetite in metamorphic rocks or by topographic effects. However, massive magnetite boulders were observed in three adjoining localities (Anomalies E2, E3, and E4, fig. 2) in area 2, and magnetite partly replacing a limestone boulder was found in area 3 (Anomaly CK3, fig. 3). Further study of these magnetite exposures is planned. In addition, two iron prospects and one lead prospect were briefly examined. All the prospects were considered small and not worthy of further study at this time.

  1. Using an improved BEMD method to analyse the characteristic scale of aeromagnetic data in the Gejiu region of Yunnan, China

    NASA Astrophysics Data System (ADS)

    Zhao, Jie; Zhao, Pengda; Chen, Yongqing

    2016-03-01

    The geological and metallogenic process is a typical non-stationary multifactor and multi-scale random process. Multiple measurement data assess the performance of the integrated process, and the combined data set is usually large and complex, among other characteristics. When different metallogenic prediction targets exist, the data must be decomposed on different scales in space. The study of the scale interval in which the object features are located can eliminate useless information and retrieve useful scale data that are needed for metallogenic prediction. Thus, the model that the specific deposit presents will be rapidly and accurately identified to enhance the efficiency of the prediction and analysis models. This paper employs an improved bidimensional empirical decomposition method to decompose aeromagnetic survey data and expresses and decomposes the spatial distribution of deposits with a mixed Gaussian model. By comparing the decomposition results on various sampling data scales with the distribution function for the deposit, the characteristic scale interval that contains the measurement information that exhibits the greatest similarity to the distribution of the deposits can be identified. This method was employed to analyse a Yunnan Gejiu tin-copper polymetallic deposit using aeromagnetic sampling data to calculate suitable decomposition-scale parameters. This approach provides valuable parameters for metallogenic prediction in other areas with aeromagnetic data.

  2. Aeromagnetic map of Nevada: Las Vegas sheet, Map 95

    SciTech Connect

    Saltus, R.W.; Ponce, D.A.

    1988-01-01

    A 1:250,000-scale map showing total intensity of the Earth's magnetic field at intervals of 10 to 500 nanoteslas, and a 1:1,000,000-scale merged aeromagnetic map. The topographic base with drainage pattern and cultural information is from the Las Vegas 1/degree/ by 2/degree/ Quadrangle. (6 refs.)

  3. Genetic and Proteomics Analyses of Space Flown Mice Skin

    NASA Astrophysics Data System (ADS)

    Terada, Masahiro; Takahashi, Rika; Yamada, Shin; Masaya, Seki; Higashibata, Akira; Majima, Hideyuki J.; Ohira, Yoshinobu; Mukai, Chiaki; Ishioka, Noriaki

    2013-02-01

    Many astronauts stay in the International Space Station (ISS) for a long period of time. Therefore, the development of astronaut health care technologies is very important. Especially, an understanding of the effects of the space environment, such as microgravity and radiation, on protein, gene, and mineral metabolism is important for developing countermeasures against the adverse effects experienced by astronauts who are in space for long periods of time. Since December 2009, the Japan Aerospace Exploration Agency (JAXA) has initiated a human research study to investigate the effects of long-term space flight on gene expression and mineral metabolism by analyzing hair samples from ISS crew members who have been in space (experiment nicknamed “HAIR”). As animal control experiments, we could have an opportunity to analyze rodents samples by participating the tissue sharing program of space-flown mice organized by Italian Space Agency (AGI) and National Aeronautics and Space Administration (NASA). It will reasonably complement human hair experiment because we able to conduct more detailed skin analysis which is enable in human experiment. The purpose of this flown-mice experiment is to study the effects of long-term exposure to space environment. In this experiment, we analyzed mice skin contained hair roots. The samples were taken from space-flown (3-month and 2-week) and 3-month hindlimb suspensioned and 3-month 2G exposed mice, and ground-control mice. For the skin contained hair roots, the extracted and amplified RNA was used to DNA microarray analysis, and was further analyzed with expression on the interesting genes by real time Reverse Transcription Polymerase Chain Reaction (RT-PCR) method. And the extracted protein was used to Mass Spectrometer analysis. Data analysis on the specimen are in progress.

  4. Detection of Aeromagnetic Field Changes Using an Unmanned Autonomous Helicopter: Repeated Experiments at Tarumae Volcano (Japan)

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Koyama, T.; Yanagisawa, T.; Yoshimoto, M.; Ohminato, T.; Kaneko, T.

    2015-12-01

    Volcanic eruptions often prohibit humans from approaching active craters. Meanwhile, it is important, especially at the initial stage of an eruption, to perform visual surveillance, geophysical/chemical measurements and material sampling in the vicinity of the craters. Besides scientific purposes, information from such surveys is helpful for the local government in deciding the response to volcanic unrest. We started airborne surveys using an unmanned helicopter on a trial basis in cooperation with the Hokkaido Regional Development Bureau. As a part of the project, we repeated aeromagnetic surveys over Mt. Tarumae (1,041m), one of the active volcanoes in northern Japan in 2011, 2012 and 2013. Owing to its high accuracy of positioning control in the autonomous flight with the aid of GPS navigation and the fairly small magnetic field gradient in the air, temporal changes up to 30 nT were successfully detected through a direct comparison between separate surveys. The field changes in the air were mostly consistent with those on the ground surface, which suggested remagnetization due to cooling beneath the summit lava dome. Through our three-year experiments, the unmanned helicopter was proved to be useful for aeromagnetic monitoring. Although the system still has some limitations in terms of maximum flight altitude and operational range from the base station, we emphasize the following three advantages of this technique. (1) Operation without exposing human to volcanic hazards. (2) Straightforward data processing procedure to obtain temporal magnetic field changes, which is especially important in an emergency response such as an ongoing unrest. (3) Great reduction of the cost to maintain ground-based monitoring stations for many years. Acknowledgments: We express sincere thanks to Muroran and Sapporo Development and Construction Departments of the HRDB for the cooperation in the field experiments using their unmanned helicopter.

  5. Aeromagnetic map of Nevada: Caliente sheet

    SciTech Connect

    Saltus, R.W.; Snyder, D.B.

    1986-12-31

    Two maps are presented, one at 1:250,000 displaying the residual magnetic field for four separate surveys, and one at 1:1,000,000 adjusting the datums to a common elevation and merging the surveys. (ACR).

  6. Hematological measurements in rats flown on Spacelab shuttle, SL-3.

    PubMed

    Lange, R D; Andrews, R B; Gibson, L A; Congdon, C C; Wright, P; Dunn, C D; Jones, J B

    1987-02-01

    Previous studies have shown that a decrease in red cell mass occurs in astronauts, and some studies indicate a leukocytosis occurs. A life science module housing young and mature rats was flown on shuttle mission Spacelab 3 (SL-3), and the results of hematology studies of flight and control rats are presented. Statistically significant increases in the hematocrit, red blood cell counts, and hemoglobin determinations, together with a mild neutrophilia and lymphopenia, were found in flight animals. No significant changes were found in bone marrow and spleen cell differentials or erythropoietin determinations. Clonal assays demonstrated an increased erythroid colony formation of flight animal bone marrow cells at erythropoietin doses of 0.02 and 1.0 U/ml but not 0.20 U/ml. These results agree with some but vary from other previously published studies. Erythropoietin assays and clonal studies were performed for the first time.

  7. Hematological measurements in rats flown on Spacelab shuttle, SL-3

    NASA Technical Reports Server (NTRS)

    Lange, R. D.; Andrews, R. B.; Gibson, L. A.; Congdon, C. C.; Wright, P.; Dunn, C. D.; Jones, J. B.

    1987-01-01

    Previous studies have shown that a decrease in red cell mass occurs in astronauts, and some studies indicate a leukocytosis occurs. A life science module housing young and mature rats was flown on shuttle mission Spacelab 3 (SL-3), and the results of hematology studies of flight and control rats are presented. Statistically significant increases in the hematocrit, red blood cell counts, and hemoglobin determinations, together with a mild neutrophilia and lymphopenia, were found in flight animals. No significant changes were found in bone marrow and spleen cell differentials or erythropoietin determinations. Clonal assays demonstrated an increased erythroid colony formation of flight animal bone marrow cells at erythropoietin doses of 0.02 and 1.0 U/ml but not 0.20 U/ml. These results agree with some but vary from other previously published studies. Erythropoietin assays and clonal studies were performed for the first time.

  8. Remagnetization of the Rush Springs Formation, Cement, Oklahoma: Implications for dating hydrocarbon migration and aeromagnetic exploration

    SciTech Connect

    Elmore, R.D.; Leach, M.C. )

    1990-02-01

    The Permian Rush Springs Formation above the Cement anticline in Oklahoma contains a Late Permian-Early Triassic chemical remanent magnetization (CRM) that is interpreted to reside in authigenic magnetite. The CRM is found in bleached, carbonate-cemented sandstones that were altered by hydrocarbons and contain authigenic magnetite. The magnetite presumably precipitated in the Late Permian-Early Triassic as a result of chemical conditions created by hydrocarbons or associated fluids that migrated from underlying reservoir units. Red sandstones around Cement that were not altered by hydrocarbons contain a Permian CRM that resides in hematite. The red and bleached sandstones have similar magnetization intensities and susceptibilities; this raises questions about the use of aeromagnetic surveys in hydrocarbon exploration.

  9. Analysis of systems hardware flown on LDEF: New findings and comparison to other retrieved spacecraft hardware

    NASA Technical Reports Server (NTRS)

    Dursch, Harry; Bohnhoff-Hlavacek, Gail; Blue, Donald; Hansen, Patricia

    1995-01-01

    The Long Duration Exposure Facility (LDEF) was retrieved in 1990 after spending 69 months in low-earth-orbit (LEO). A wide variety of mechanical, electrical, thermal, and optical systems, subsystems, and components were flown on LDEF. The Systems Special Investigation Group (Systems SIG) was formed by NASA to investigate the effects of the 69 month exposure on systems related hardware and to coordinate and collate all systems analysis of LDEF hardware. This report is the Systems SIG final report which updates earlier findings and compares LDEF systems findings to results from other retrieved spacecraft hardware such as Hubble Space Telescope. Also included are sections titled (1) Effects of Long Duration Space Exposure on Optical Scatter, (2) Contamination Survey of LDEF, and (3) Degradation of Optical Materials in Space.

  10. US experiment flown on the Soviet biosatellite Cosmos 1667

    NASA Technical Reports Server (NTRS)

    Hines, John W. (Editor); Skidmore, Michael G. (Editor)

    1994-01-01

    Two male young-adult rhesus monkeys were flown on the Soviet Biosatellite Cosmos 1667 for seven days from July 10-17, 1985. Both animals were instrumented to record neurophysiological parameters. One animal, Gordyy, was additionally instrumented to record cardiovascular changes. Space capsule and environmental parameters were very similar to those of previous missions. On Cosmos 1514, which flew for five days in 1983, one animal was fitted with a left carotid artery cuff to measure blood pressure and flow velocity. An additional feature of Cosmos 1667 was a postflight control study using the flight animal. Intermittent postural tilt tests were also conducted before and after spaceflight and synchronous control studies, to simulate the fluid shifts associated with spaceflight. The experiment results support the conclusion derived from Cosmos 1514 that significant cardiovascular changes occur with spaceflight. The changes most clearly seen were rapid initial decreases in heart rate and further decreases with continued exposure to microgravity. The triggering mechanism appeared to be a headward shift in blood and tissue fluid volume which, in turn, triggered adaptive cardiovascular changes. Adaptive changes took place rapidly and began to stabilize after the first two days of flight. However, these changes did not plateau in the animal by the last day of the mission.

  11. Curie point depth from spectral analysis of aeromagnetic data for geothermal reconnaissance in Afghanistan

    NASA Astrophysics Data System (ADS)

    Saibi, H.; Aboud, E.; Gottsmann, J.

    2015-11-01

    The geologic setting of Afghanistan has the potential to contain significant mineral, petroleum and geothermal resources. However, much of the country's potential remains unknown due to limited exploration surveys. Here, we present countrywide aeromagnetic data to estimate the Curie point depth (CPD) and to evaluate the geothermal exploration potential. CPD is an isothermal surface at which magnetic minerals lose their magnetization and as such outlines an isotherm of about 580 °C. We use spectral analysis on the aeromagnetic data to estimate the CPD spatial distribution and compare our findings with known geothermal fields in the western part of Afghanistan. The results outline four regions with geothermal potential: 1) regions of shallow Curie point depths (∼16-21 km) are located in the Helmand basin. 2) regions of intermediate depths (∼21-27 km) are located in the southern Helmand basin and the Baluchistan area. 3) Regions of great depths (∼25-35 km) are located in the Farad block. 4) Regions of greatest depths (∼35-40 km) are located in the western part of the northern Afghanistan platform. The deduced thermal structure in western Afghanistan relates to the collision of the Eurasian and Indian plates, while the shallow CPDs are related to crustal thinning. This study also shows that the geothermal systems are associated with complex magmatic and tectonic association of major intrusions and fault systems. Our results imply geothermal gradients ranging from 14 °C/km to 36 °C/km and heat-flow values ranging from 36 to 90 mW/m2 for the study area.

  12. Analysis of Aeromagnetic data of the NE region of the Indian sub-continent.

    NASA Astrophysics Data System (ADS)

    Rajaram, M.; S. P, A.

    2007-12-01

    The NE region of the Indian subcontinent is a very interesting place for geodynamic and tectonic studies due to the collision of the Indian plate with the Himalayas in the North and with Myanmar in the East. Some of these areas are difficult to access due to the high topography and air borne surveys help map the region efficiently. Further, the NE region including areas of Assam and Bangladesh are drained by the Ganges and Brahmaputra rivers that bring thick sediments with them giving rise to the Bengal Fan that has sediments of up to 20 km in some regions and these mask the underlying crust and pose severe restrictions in constructing the geodynamical history of the region. Geopotential data offer the unique opportunity of addressing some of these issues. We utilize available / published aeromagnetic maps over Bangladesh, Meghalaya, Chachar, parts of North Assam, Brahmaputra valley, Manipur and Nagaland in the North Eastern region of India for understanding the complexities of the tectonics of the Indian sub-continent. All available data are reduced to a common altitude to prepare a composite magnetic anomaly map of the region. We also look at the Grace and Bouguer / isostatic gravity maps of the region; the highest isostatic gravity anomaly of the Indian region lies over Meghalaya with a trough in Sylhet (Bangladesh) to its south. The Eocene hinge zone is a 25-km wide northeast-southwest zone that separates the Precambrian platform in the northwest from the geosynclinal basin to the southeast of Bangladesh. We find that the Hinge Zone in Bangladesh and part of the Dauki fault form a strong divide such that the gravity anomalies and aeromagnetic anomalies show high frequency anomalies to the north of this divide and also most of the magnetic sources as seen from the analytic signal are concentrated to the north and the Euler solutions give shallow solutions to the north and deep solutions to the south of this divide. The tilt derivative of the aeromagnetic data

  13. Compatibility study of the MAGSAT data and aeromagnetic data

    NASA Technical Reports Server (NTRS)

    Won, I. J. (Principal Investigator)

    1981-01-01

    The results of (1) an analysis of the fine attitude MAGSAT data covering the continental U.S., (2) analysis of the Project MAGNET U.S. aeromagnetic data in terms of its compatibility with the corresponding MAGSAT data, and finally, (3) analysis of MAGSAT data in the Pacific region and comparison with satellite gravity data are presented. All data reduction procedures are described and the resulting magnetic maps are given. The results indicate a general compatibility between the MAGSAT data and the MAGNET and gravity data.

  14. MAGSAT and aeromagnetic data in the North American continent

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Problems were encountered in deriving a proper reference field to be subtracted from the aeromagnetic data obtained from Project MAGNET. Field models tried thus far do not seem to eliminate properly the main field. The MAGSAT data in the North American continent for the period November 1 to December 22, 1979 are being compiled and compared with MAGNET data. Efforts are being made to eliminate the orbital bias errors. A computer program was developed and successfully tested which computes a topographic profile of the Curie depth isotherm which fits best to the observed vector or scalar field magnetic data.

  15. Outgassing of Flown and Unflown MIR Solar Cells

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.; Kinard, William H.; Wilson, Linda A.

    2000-01-01

    A solar panel array with more than ten years space exposure was removed from the Mir core module in November 1997, and an eight panel section was returned to Earth in January 1998. Several solar cells were removed from panel eight of the returned array and placed in a high vacuum system with a residual gas analyzer (200 amu mass spectrometer) and a cold finger. Similar unflown solar cells of the same vintage were later obtained from Energia. Several of the unflown cells were also placed in the vacuum system and outgassed residues were collected on the LN2 cold finger. Almost 3 mg of outgassed residue was collected -from a string of three unflown solar cells over a period of 94 hours under vacuum. The collected residue was weighed with a microbalance, and then the residue was analyzed by FTIR spectroscopy, and by gas chromatograph-mass spectroscopy. About 25 outgassed constituents were separated by the gas chromatograph, and a high-resolution mass spectrum was obtained of each constituent. Molecular identifications have been made for the constituents. The constituents are primarily cyclic siloxanes, and several of the constituents are isomers of the same molecule. Most of the outgassed constituents have a molecular mass of about 500 amu. Almost one mg of residue was extracted from one sq cm of coverglass/adhesive from a flown solar cell by soaking in isopropyl alcohol for 30 minutes. The gas chromatograph separated about 20 constituents. The constituents are mostly cyclic siloxanes with linear branches, hydrocarbons, and phthalates. The typical molecular mass is about 600 amu. These identifications of specific outgassing molecules have resulted in a more complete understanding of the SiO(x) contamination on the Mir solar cell coverglasses, and on the MEEP experiment trays and optical specimens during the Shuttle-Mir Phase One flight experiment program. Adjusted outgassing rates based on the data reported here, and/or measured outgassing rates and specific molecular

  16. Preliminary Aeromagnetic Map of Joshua Tree National Park and Vicinity, Southern California

    USGS Publications Warehouse

    Langenheim, V.E.; Hill, P.L.

    2010-01-01

    This aeromagnetic map of Joshua Tree National Park and vicinity is intended to promote further understanding of the geology and structure in the region by serving as a basis for geophysical interpretations and by supporting geological mapping, water-resource investigations, and various topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals commonly mark lithologic or structural boundaries. Bodies of mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because rocks with more felsic compositions, or even some sedimentary units, also can cause measurable magnetic anomalies. The database includes two ASCII files containing new aeromagnetic data and two ASCII files with point locations of the local maximum horizontal gradient derived from the aeromagnetic data. This metadata file describes the horizontal gradient locations derived from new and existing aeromagnetic data. This aeromagnetic map identifies magnetic features as a basis for geophysical interpretations; the gradients help define the edges of magnetic sources. This database updates geophysical information originally presented in smaller-scale formats and includes detailed aeromagnetic data collected by EON Geosciences, Inc.

  17. New insights into the structure of Norwegian continental margins from modern aeromagnetic compilations

    NASA Astrophysics Data System (ADS)

    Ebbing, J.; Olesen, O.; Gernigon, L.; Skilbrei, J. R.

    2007-12-01

    We present the aeromagnetic compilation of the Norwegian mainland and its shelf area and its importance for geological models and tectonic studies. The combined data-set reveal that the bedrock structures are continuous from the Baltic Shield under the Caledonian orogen into the continental shelf and that the late-Caledonian collapse of the Caledonian orogene has influenced the style of extension on the Norwegian shelf. On the margin, modern high-resolution aeromagnetic surveys with small line-spacing, more accurate navigation and sensitive magnetometers have revealed the existence of significant magnetic anomalies arising from sedimentary layers. Sub-cropping Late Paleozoic to Tertiary sedimentary units along the Trøndelag-Nordland coast produce a very distinct anomaly pattern. The asymmetry of the anomalies, with a steep gradient and a negative anomaly to the east and a more gentle gradient to the west, relate the anomalies to a strata gently dipping westward. Susceptibility measurements on core samples, hand specimens and in situ on bedrock exposures are essential for the interpretation of these anomalies. Remapping of the oceanic crust has also improved our under-standing of the Tertiary opening of the North Atlantic as previously interpreted oceanic fracture zones zones do not exist; these were artefacts of poor navigation and wide line spacing of the vintage datasets. Tectonic reconstruction has shown that the opening of the Norwegian-Greenland Sea between the Jan Mayen and Senja fracture zones occurred along a stable axis without offsets of the oceanic spreading anomalies and without jumps in spreading axis. Transfer zones have previously been associated with oceanic fracture zones along the Mid-Norwegian and East-Greenland margins. Transfer zones are important entry points for sedimentary drainage systems, a relationship that has also been suggested for the transport of Cretaceous sands to the mid-Norwegian margin. Our new interpretation has consequently

  18. Aeromagnetic evidence for a volcanic caldera(?) complex beneath the divide of the West Antarctic Ice Sheet

    USGS Publications Warehouse

    Behrendt, John C.; Finn, C.A.; Blankenship, D.; Bell, R.E.

    1998-01-01

    A 1995-96 aeromagnetic survey over part of the Sinuous Ridge (SR) beneath the West Antarctic Ice Sheet (WAIS) divide shows a 70-km diameter circular pattern of 400-1200-nT anomalies suggesting one of the largest volcanic caldera(?) complexes on earth. Radar-ice-sounding (RIS) shows the northern part of this pattern overlies the SR, and extends south over the Bentley Subglacial Trench (BST). Modeled sources of all but one the caldera(?) anomalies are at the base of <1-2-km thick ice and their volcanic edifices have been glacially removed. The exception is a 700-m high, 15-km wide 'volcano' producing an 800-nT anomaly over the BST. 'Intrusion' of this 'volcano' beneath 3 km of ice probably resulted in pillow basalt rather than easily removed hyaloclastite erupted beneath thinner ice. The background area (-300 to -500-nT) surrounding the caldera(?) is possibly caused by a shallow Curie isotherm. We suggest uplift of the SR forced the advance of the WAIS.A 1995-96 aeromagnetic survey over part of the Sinuous Ridge (SR) beneath the West Antarctic Ice Sheet (WAIS) divide shows a 70-km diameter circular pattern of 400-1200-nT anomalies suggesting one of the largest volcanic caldera(?) complexes on earth. Radar-ice-sounding (RIS) shows the northern part of this pattern overlies the SR, and extends south over the Bentley Subglacial Trench (BST). Modeled sources of all but one the caldera(?) anomalies are at the base of < 1-2-km thick ice and their volcanic edifices have been glacially removed. The exception is a 700-m high, 15-km wide 'volcano' producing an 800-nT anomaly over the BST. 'Intrusion' of this 'volcano' beneath 3 km of ice probably resulted in pillow basalt rather than easily removed hyaloclastite erupted beneath thinner ice. The background area (-300 to -500-nT) surrounding the caldera(?) is possibly caused by a shallow Curie isotherm. We suggest uplift of the SR forced the advance of the WAIS.

  19. MAGSAT and aeromagnetic data of the continental US

    NASA Technical Reports Server (NTRS)

    Won, I. J. (Principal Investigator)

    1982-01-01

    The MAGSAT data were used to produce a scalar anomaly map of the U.S. In order to remove the east-west striping anomalies, which are believed to be caused by the low-order polynomials used to reduce the orbital bias errors, a 2-D spectral filtering using the Fourier transform method was applied. The resultant low-pass filtered map, with the east-west stripings removed, resembles much closer the surface aeromagnetic map based on the U.S. MAGNET data. The spectral filtering was also applied to the MAGSAT vector data. Department of Defense gravity data was processed to produce a filtered U.S. gravity map whose spectral contents are comparable to those of the MAGSAT magnetic map.

  20. Detailed aeromagnetic investigation of the Arctic Basin. II

    NASA Technical Reports Server (NTRS)

    Taylor, P. T.; Kovacs, L. C.; Vogt, P. R.; Johnson, G. L.

    1981-01-01

    Remote sensing techniques must be employed to determine the nature of the regional geologic and tectonic structure of the Arctic Basin. Magnetic measurements from aircraft are the most commonly used method. Since 1972 the U.S. Navy has been engaged in a long-term program of mapping, in relative detail, the earth's magnetic field over that portion of the Arctic Basin accessible to the P3 aircraft. A description is presented of the results of the 1977 and 1978 field efforts. The description represents a continuation of an investigation reported by Vogt et al. (1979). The efforts currently considered were directed towards understanding the nature, age, and origin of the major physiolographic features of the western Arctic Basin. Particular attention was given to the Canada and Makarov basins (Fletcher Abyssal Plain) and the Alpha Ridge. The aeromagnetic data are interpreted with respect to the theory of origin presented by Carey (1958).

  1. Arkansas and Louisiana Aeromagnetic and Gravity Maps and Data - A Website for Distribution of Data

    USGS Publications Warehouse

    Bankey, Viki; Daniels, David L.

    2008-01-01

    This report contains digital data, image files, and text files describing data formats for aeromagnetic and gravity data used to compile the State aeromagnetic and gravity maps of Arkansas and Louisiana. The digital files include grids, images, ArcInfo, and Geosoft compatible files. In some of the data folders, ASCII files with the extension 'txt' describe the format and contents of the data files. Read the 'txt' files before using the data files.

  2. A Review of Aeromagnetic Anomalies in the Sawatch Range, Central Colorado

    USGS Publications Warehouse

    Bankey, Viki

    2010-01-01

    This report contains digital data and image files of aeromagnetic anomalies in the Sawatch Range of central Colorado. The primary product is a data layer of polygons with linked data records that summarize previous interpretations of aeromagnetic anomalies in this region. None of these data files and images are new; rather, they are presented in updated formats that are intended to be used as input to geographic information systems, standard graphics software, or map-plotting packages.

  3. A preliminary comparison of the Magsat data and aeromagnetic data in the continental U.S.

    NASA Technical Reports Server (NTRS)

    Won, I. J.; Son, K. H.

    1982-01-01

    A preliminary regional scale magnetic anomaly map derived from the Magsat data over the continental U.S. shows reasonably good correlations when compared with the corresponding aeromagnetic map. This conclusion is based upon the analysis of the fine attitude scalar Magsat data of about a two-month duration starting November 2, 1979 and the analysis of the Project Magnet U.S. aeromagnetic data in the same region.

  4. An aeromagnetic and aeroradioactivity overview of the Colorado Front Range

    SciTech Connect

    Reed, J.C. Jr. . Federal Center); Zietz, I. . Inst. for Geographical and Geological Sciences); Duval, J.S. )

    1992-01-01

    Aeromagnetic and aeroradioactivity data acquired along 1-mile spaced flight lines at 400 ft above terrain during the DOE-NURE program have been compiled to provide a synoptic overview of the Colorado Front Range between 38[degree] and 41[degree] N. These data constitute one of the largest blocks of systematically collected data of this type in the US. Features related to surface geology clearly shown on the aeromagnetic map include major northeast-trending Precambrian shear zones, trends of steeply dipping foliation (but not foliation with shallow dip), and a variety of Proterozoic, Mesozoic and Tertiary plutons, some of which show hitherto unrecognized internal subdivisions. A conspicuous north-south trending discontinuity in the western part of the Precambrian core of the range does not correlate closely with surface geology and may be related to downward steepening of east-dipping Laramide thrust faults that bound the Precambrian rocks along the west side of the range. Seismic and/or gravity data may help test this interpretation. The aeroradioactivity maps show many details of the outcropping plutons, including major differences in U, Th, K contents of plutons of the same general age, subtle compositional gradients within individuals plutons, and the location of individual intrusive centers in the Pikes Peak batholith. Distribution of alluvium derived from high U-Th plutons and trends of Tertiary paleovalleys containing high-U ash-flow tuffs are also locally evident. Compilations of geophysical data of this type and scale provide an invaluable overview for studies of regional tectonics, structure, and plutonism in crystalline terranes, even where surface geology is reasonably well known.

  5. Subglacial volcanic features beneath the West Antarctic Ice Sheet interpreted from aeromagnetic and radar ice sounding

    USGS Publications Warehouse

    Behrendt, John C.; Blankenship, D.D.; Morse, D.L.; Finn, C.A.; Bell, R.E.

    2002-01-01

    The West Antarctic Ice Sheet (WAIS) flows through the volcanically active, late Cenozoic West Antarctic rift system. Active subglacial volcanism and a vast (>106 km3) extent of subglacial volcanic structures have been interpreted from aerogeophysical surveys over central West Antarctica in the past decade, combined with results from 1960s and 1970s aeromagnetic profiles over the WAIS. Modelling of magnetic anomalies constrained by radar ice sounding shows volcanic sources at the base of the ice throughout large areas, whose subglacially erupted hyaloclastite edifices have been eroded by moving ice, as in Iceland. The 1800 m-high divide of the WAIS is underlain by the 400 km-long volcanic Sinuous Ridge, which rises above sea level; most hyaloclastite edifices there have also been glacially removed, indicating migration of the ice divide through time. Northeast of the divide of the WAIS there is a 400-nT positive magnetic anomaly over the shallowest, most rugged bedrock topography (elevation +380 m above sea level), probably comprising subaerially erupted flows erupted when the Sinuous Ridge area was deglaciated. Uplift of the Sinuous Ridge may have forced the advance of the WAIS. Other aspects of the subglacial volcanism in Antarctica can be observed in Iceland and have a direct bearing on our understanding of the subglacial conditions of the WAIS and its dynamics.

  6. Aeromagnetic and Aeroradiometric Data for the Conterminous United States and Alaska from the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy

    USGS Publications Warehouse

    Hill, Patricia L.; Kucks, Robert P.; Ravat, Dhananjay

    2009-01-01

    The National Uranium Resource Evaluation (NURE) program was initiated in 1973 with a primary goal of identifying uranium resources in the United States. The airborne program's main purpose was to collect radiometric data of the conterminous United States and Alaska. Magnetic data were also collected. After the program ended, most of the data were given to the U.S. Geological Survey (USGS). All areas were flown at about 400 feet above ground, the optimum height for collecting radiometric data, and the line spacing varied from 3 to 6 mile intervals. A few selected quadrangles or parts of quadrangles were flown at 1- or 2-mile line spacing. About forty smaller areas were targeted and flown at 0.25-mile to 1 mile line spacing.

  7. Spaceflight Effects on Hemopoiesis of Lower Vertebrates Flown on Foton-M2

    NASA Technical Reports Server (NTRS)

    Domaratskaya, E. I.; Payushina, O. V.; Butorina, M. N.; Nikonova, T. M.; Grigorian, E. N.; Mitashov, V. I.; Tairbekov, M. G.; Almeida, E.; Khrushchov, N. G.

    2006-01-01

    Intact and operated newts Pleumdeles waltl flown on Foton-M2 for 16 days were used to study the effects of spaceflight as well as tail amputation and lensectomy on their hemopoiesis. The flight did not produce noticeable changes in the peripheral blood of nonoperated newts. However, in operated animals, the number of lymphocytes increased whereas that of neutrophils decreased. There were no morphological differences in hemopoietic organs (liver and spleen) between flown non-operated and operated animals or their controls. However, in both non-operated and operated newts the liver weight and the number of hemopoietic cells in it increased. In contrast to nonoperated newts, space-flown mammals typically showed significant changes in blood cell counts. Experiments with BrdU incorporation revealed labeled cells in the hemopoietic area of the liver as well as in blood and spleen. This observation gives evidence that the BrdU label can be used to study proliferation of hemopoietic cells.

  8. Changes in subcellular morphologies, defense enzyme and genetic characteristics in earth-grown tomato seedlings propagated from six year Mir-flown seeds and 27 day recovery satellite-flown seeds

    NASA Astrophysics Data System (ADS)

    Lu, Jinying; Liu, Min; Xue, Huai; Pan, Yi; Han, Xinyun; Kan, Sheng; Nechitailo, Galina S.

    Subcellular, changes of enzymes activities and genetic characteristics were compared between Earth-grown plants from the original tomato seeds, 6-year long-term flown in the Mir and 27- day short-term flown in the satellite. In some Mir-flown plants, the lamellae's structure of some chloroplasts became curved and loose, and some mitochondrial outer membranes were broken. In some satellite-flown plants, the number of mitochondria increased, the lamellae's structure of some chloroplasts became curved and loose, and some mitochondrial cristae disappeared. The number of starch grains per chloroplast in Mir-flown plants and satellite-flown plants increased significantly compared with the ground control. The number of chloroplasts per leaf cell in Mir-flown plants and satellite-flown plants decreased significantly compared with the ground control. The activities of three defense enzymes SOD, POD and CAT in the satellite -flown plants increased significantly as compared with those of the ground controls and the Mir-flown plants, but the content of MDA decreased significantly. Coefficients of variation of the activities of SOD, POD, CAT and the content of MDA in the satellite -flown plants were lest, and those in the Mir-flown plants were maximum. Among the 90 pair of SSR primers used for the genome DNA PCR analyses, the total number of SSR bands in the Mir-flown plants was the same 90 bands as in the control. Different DNA band types were generated from 7 pairs of SSR primers with a 7.78% polymorphism between the control and the 15 Mir-flown plants. Of 8 polymorphic bands, the SSR fragment size in 4 bands was larger and 4 smaller in the Mir-flown plants than that in the control. Different DNA band types were generated from 5 pairs of SSR primers with a 5.56% polymorphism between the control and one satellite-flown plant. The total number of SSR bands in one satellite-flown plant was 95 bands, of which 90 bands were the same with the ground control and 5 bands were

  9. Quantitative analysis of scale of aeromagnetic data raises questions about geologic-map scale

    USGS Publications Warehouse

    Nykanen, V.; Raines, G.L.

    2006-01-01

    A recently published study has shown that small-scale geologic map data can reproduce mineral assessments made with considerably larger scale data. This result contradicts conventional wisdom about the importance of scale in mineral exploration, at least for regional studies. In order to formally investigate aspects of scale, a weights-of-evidence analysis using known gold occurrences and deposits in the Central Lapland Greenstone Belt of Finland as training sites provided a test of the predictive power of the aeromagnetic data. These orogenic-mesothermal-type gold occurrences and deposits have strong lithologic and structural controls associated with long (up to several kilometers), narrow (up to hundreds of meters) hydrothermal alteration zones with associated magnetic lows. The aeromagnetic data were processed using conventional geophysical methods of successive upward continuation simulating terrane clearance or 'flight height' from the original 30 m to an artificial 2000 m. The analyses show, as expected, that the predictive power of aeromagnetic data, as measured by the weights-of-evidence contrast, decreases with increasing flight height. Interestingly, the Moran autocorrelation of aeromagnetic data representing differing flight height, that is spatial scales, decreases with decreasing resolution of source data. The Moran autocorrelation coefficient scems to be another measure of the quality of the aeromagnetic data for predicting exploration targets. ?? Springer Science+Business Media, LLC 2007.

  10. Quality assurance of aeromagnetic data using lineament analysis

    NASA Astrophysics Data System (ADS)

    Lee, Madeline; Morris, William

    2013-01-01

    Lineament analysis is typically applied to geoscientific data to identify lithological contacts, faults, fractures and dyke swarms. We implement lineament analysis as a method for quantifying the adequacy of pre-processing of airborne magnetic datasets. This is accomplished through the identification of noise due to inappropriate levelling. Lineament analysis involves the extraction of linear features from a dataset using visual and/or automatic interpretation techniques and the statistical and directional analyses of these extracted lineaments. We apply lineament analysis to a levelled high resolution aeromagnetic dataset from the Northwest Territories, Canada, to assess the levelling quality. A priori knowledge will include geology defining regional tectonic trends such as fault systems and dyke swarms. Analysis of a lineament's azimuth separates assumed geologic sources and noise associated with data acquisition or processing artefacts. The lineament azimuths are assessed as rose diagrams. This is an alternative method to standard computation of 2D radially averaged power spectrums in the frequency domain and sunshading orthogonal to flight path. The rose diagrams are compared with the 2D power spectrums which both provide quantitative directional information; however, the power spectrum provides spectral frequency content and rose diagrams provide frequency of occurrence. Calculation of the number of lineaments along a particular azimuth before and after pre-processing quantifies the degree to which flight-line variations have been suppressed and geological signal more apparent.

  11. Developing a fixed-wing UAV aeromagnetic system

    NASA Astrophysics Data System (ADS)

    Ziqi, G.

    2013-12-01

    This invention relates to a fixed-wing unmanned aerial vehicle (UAV) aeromagnetic system which is suitable for geophysical prospecting using earth magnetic fields and to develop a low cost, easy operation, reliable performance of aerial magnetic detection system. This system depends mainly upon the measurement of the magnetic properties of the underlying ground. This big project contained unmanned aerial vehicle system, battery system for power source, navigation and flight control system, magnetometer, the magnetic compensation and data processing system and compare with the ground demonstration area. Each of them is a complex engineer system. We made two kind of fixed-wing UAV which designed for different magnetometers such as Helium airborne optical pumping magnetometer and SQUID magnetometer. The battery designed to endure large range temperature varied from -30 to 60 Celsius degree with a dual-redundancy system. A primary object of the invention to provide a fixed-wing UAV for deep exploration using natural magneto-telluric fields as an energy source and operating in a frequency of 20Hz, the System integrated precision of 2nT ranged from 19000 nT to 74000 nT, Meeting the demand of global resources exploration. Another object is it can operate at much higher terrain to 5000km. Yet another object of the invention is providing a system that can explore for mineral deposits with mountain and some other terrain. This paper Sponsored by the project of Chinese deep explorations (SinoProbe09-03)

  12. Aeromagnetic investigation of southern Calabria and the Messina Straits (Italy): Tracking seismogenic sources of 1783 and 1908 earthquakes

    NASA Astrophysics Data System (ADS)

    Minelli, Liliana; Vecchio, Antonio; Speranza, Fabio; Nicolosi, Iacopo; D'Ajello Caracciolo, Francesca; Chiappini, Stefano; Carluccio, Roberto; Chiappini, Massimo

    2016-03-01

    Southern Calabria and the NE corner of Sicily (Italy) were struck in 1783 and 1908 A.D. by two of the most catastrophic earthquakes ever in European history. Although it is generally acknowledged that the seisms were yielded by normal faults rupturing the upper crust of the Calabria-Peloritani terrane, no consensus exists on seismogenic source location and orientation. Here we report on a high-resolution low-altitude aeromagnetic survey of southern Calabria and Messina Straits. In southern Calabria we document a broad weakly positive (5-10 nT) anomaly zone interrupted by three en echelon SW-NE null to negative magnetic anomaly corridors. Euler deconvolution and magnetic modeling show that the anomaly pattern is produced by a 1-1.5 km thick crustal "layer" located within 3 km depth. This layer is offset by a 25 km long NE trending fault that corresponds to the Armo normal fault, recently inferred to be the source for the 1908 earthquake. Few kilometers to the south, we also document a subparallel and previously unrecognized fault, entering the Messina Straits and likely joining the Armo fault at depth. Further east, we model a 40 km long normal fault, probably extending northeastward for additional 40 km, running along the south Calabria axis from Aspromonte to the Serre mountains and partly following the 18 km long surface rupture witnessed by Déodat de Dolomieu after the 1783 earthquake. Thus, aeromagnetic data suggest that the sources of the 1783 and 1908 earthquakes are en echelon faults belonging to the same NW dipping normal fault system straddling the whole southern Calabria.

  13. Analysis of James Ross Island volcanic complex and sedimentary basin based on high-resolution aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Ghidella, M. E.; Zambrano, O. M.; Ferraccioli, F.; Lirio, J. M.; Zakrajsek, A. F.; Ferris, J.; Jordan, T. A.

    2013-02-01

    High-resolution aeromagnetic surveys provide a geophysical tool to help image the subsurface structure of volcanoes and their tectonic framework. Here we interpret high-resolution aeromagnetic data and models for James Ross archipelago and surrounding regions to provide a new perspective on Neogene magmatism emplaced along the eastern margin of the Antarctic Peninsula. Based on the analysis and modelling of magnetic anomalies we were able to image the subglacial extent of Miocene to Recent alkaline rocks of the James Ross Island Volcanic Group and map tectonic structures that appear to have exerted important controls on Neogene magmatism. High-amplitude linear anomalies detected over Mount Haddington stratovolcano were modelled as caused by subvertical feeder bodies extending to a depth of at least 3 km. These feeder bodies may have been emplaced along a N-S oriented volcano-tectonic rift zone. We also identified several effusive subglacial centres and imaged two concentric magnetic arcs, which we related to Neogene volcanic and subvolcanic lineaments, likely controlled by Mid-Cretaceous strike-slip fault belts and associated deformation zones. The regional magnetic quiet zone that encompasses James Ross Island is caused by the thick sedimentary infill of the Larsen Basin, and a low-amplitude magnetic high within the basin is inferred to reflect a basement push-up structure associated with strike-slip faulting along the eastern edge of the Antarctic Peninsula. In the offshore regions magnetic anomalies southwest of Tabarin Peninsula and west of Vega Island may reflect recent volcanic structures that have yet to emerge from the sea-floor.

  14. The aeromagnetic method as a tool to identify Cenozoic magmatism in the West Antarctic Rift System beneath the West Antarctic Ice Sheet: a review; Thiel subglacial volcano as possible source of the ash layer in the WAISCOR

    USGS Publications Warehouse

    Behrendt, John C.

    2013-01-01

    The West Antarctic Ice Sheet (WAIS) flows through the volcanically active West Antarctic Rift System (WARS). The aeromagnetic method has been the most useful geophysical tool for identification of subglacial volcanic rocks, since 1959–64 surveys, particularly combined with 1978 radar ice-sounding. The unique 1991–97 Central West Antarctica (CWA) aerogeophysical survey covering 354,000 km2 over the WAIS, (5-km line-spaced, orthogonal lines of aeromagnetic, radar ice-sounding, and aerogravity measurements), still provides invaluable information on subglacial volcanic rocks, particularly combined with the older aeromagnetic profiles. These data indicate numerous 100–>1000 nT, 5–50-km width, shallow-source, magnetic anomalies over an area greater than 1.2 × 106 km2, mostly from subglacial volcanic sources. I interpreted the CWA anomalies as defining about 1000 “volcanic centers” requiring high remanent normal magnetizations in the present field direction. About 400 anomaly sources correlate with bed topography. At least 80% of these sources have less than 200 m relief at the WAIS bed. They appear modified by moving ice, requiring a younger age than the WAIS (about 25 Ma). Exposed volcanoes in the WARS are The present rapid changes resulting from global warming, could be accelerated by subglacial volcanism.

  15. Crustal structure and tectonic development of Gulf of Guinea Cul-deSac from integrated interpretation of new aeromagnetic and existing geophysical data

    SciTech Connect

    Babalola, O.O.

    1985-02-01

    Data-acquisition difficulties and propriety restrictions on industry data have necessitated liberal extrapolations and generalizations in previous tectono-structural studies of the Gulf of Guinea cul-de-sac. This region is the locus of a postulated Late Cretaceous triple junction whose arms were the transform-dominated Equatorial Atlantic, the northward-propagating South Atlantic, and the Benue Trough aulacogen. Oceanic crust has been inferred to underlie most of the thick sedimentary wedge of the oil-prolific Niger Delta basin. Integrated interpretation of new aeromagnetic data of the Geological Survey of Nigeria and existing geophysical data corroborates previous work on the general structure of the marginal basins. New aeromagnetic data, however, reveal a detail structure more complex than previously known. Low-frequency magnetic anomalies over the Niger delta indicate that oceanic crust extends northward to about Onitsha. From Onitsha, the edge of oceanic crust extends northward to about Onitsha. From Onitsha, the edge of oceanic crust trends southwestward along the Benin hinge line (an apparent continental continuation of either the Chain fracture zone or a new Okitipupa fracture zone) and also wiggles southeastward (adjoined by a wide margin of transitional crust) toward the shelf break off Cameroon. Linear magnetic anomalies trending northeast indicate about 7 fracture zones beneath the Niger Delta basin. The region of high-frequency magnetic anomalies west of the Niger delta represent the Okitipupa basement ridge complex, which separates the Niger Delta basin from the Dahomey embayment. In this embayment, 2 wide bands of intervening high- and low-frequency aeromagnetic anomalies are interpreted to represent a basement high or ridge and a fault-bonded trough, respectively.

  16. Growth and development of plants flown on the STS-3 Space Shuttle mission

    NASA Technical Reports Server (NTRS)

    Cowles, J. R.; Scheld, H. W.; Peterson, C.; Lemay, R.

    1984-01-01

    Pre-germinated pine seedlings and germinating oat and mung bean seeds were flown on the STS-3 Space Shuttle mission. Overall, the seedlings grew and developed well in space. Some oat and mung bean roots, however, grew upward. Lignin content was slightly lower in flight tissues and protein content was higher.

  17. Effects of space exposure on metals flown on the Long Duration Exposure Facility

    NASA Technical Reports Server (NTRS)

    Pippin, H. Gary; Bourassa, R. J.

    1995-01-01

    This report includes measurements on copper, aluminum, and stainless steel from the Long Duration Exposure Facility (LDEF). Summaries of the performance of a variety of metals flown on LDEF are presented. An extensive list of references directs the reader to other detailed investigations. The influence of contamination on a number of measurements is documented.

  18. Growth and development of plants flown on the STS-3 space shuttle mission

    NASA Astrophysics Data System (ADS)

    Cowles, J. R.; Scheld, H. W.; Peterson, C.; LeMay, R.

    Pre-germinated pine seedlings and germinating oat and mung bean seeds were flown on the STS-3 Space Shuttle mission. Overall, the seedlings grew and developed well in space. Some oat and mung bean roots, however, grew upward. Lignin content was slightly lower in flight tissues and protein content was higher.

  19. Nature and Geometry of tectonic elements associated with Bhuj Earthquake from High resolution Aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Rajaram, M.; S. Prasanna, A.

    2010-12-01

    The Kutch Rift basin is an important tectonic unit of Indian sub-continent where the disastrous Bhuj earthquake of Mw 7.8 occurred on 26 January 2001 (republic day of India) killing more than 20,000 people and leaving over 6,00,000 people homeless. The Bhuj earthquake was considered as one of the largest intraplate earthquake. Although liquefaction phenomenon and mud volcanoes were reported, no surface rupture was reported; generally an earthquake of this magnitude is associated with surface ruptures. Following the earthquake several Geophysical studies like Magnetotelluric, gravity, geomagnetic depth sounding, long period magnetotelluric, GPS and others were undertaken to understand the cause of this massive intra-plate earthquake. Despite these efforts several enigmatic questions related to the earthquake and the tectonic setting of the Kutch region still remain unanswered one of them being the location of the fault plane associated with the Mainshock of the Bhuj earthquake: is it the Kutch Mainland fault (KMF) or the south dipping North Wagad fault 25 km north of the KMF. Much of the earthquake affected region was covered by inaccessible salt plains due to which the existing geophysical data coverage is very poor. A semi detailed high-resolution airborne magnetic survey, with line spacing of 1km,was conducted during the period January 23, 2008 to May 16, 2008 covering an area of 56593 Sq.Km over the Kutch basin and surrounding areas. The objective of the survey was to acquire high resolution magnetic data to map the anomalous magnetic field distribution pattern in order to understand the lithology and sub surface structural settings in aid of geological interpretation for various purposes. From an analysis of the generated aeromagnetic map we were able to bring out signatures of several hitherto unknown faults and intrusives. We find that the epicenter of the main shock of Bhuj earthquake lies on the intersection point of three faults, a kind of triple point

  20. General aviation activity survey. Annual summary report for 1992

    SciTech Connect

    Not Available

    1992-01-01

    This report presents the results of the annual General Aviation Activity Survey. The survey is conducted by the FAA to obtain information on the flight activity of the United States registered general aviation aircraft fleet. The report contains breakdowns of active aircraft, annual flight hours, average flight hours and other statistics by manufacturer/model group, aircraft type, state and region of based aircraft, and primary use. Also included are fuel consumption, lifetime airframe hours, engine hours, miles flown estimates, estimates of the number of landings, IFR hours flown, and grade of fuel consumed by the general aviation fleet. Aircraft, Aircraft activity, Aircraft use, Fuel consumption, General aviation, Hours flown, Miles flown.

  1. Interpretation of Gravimetric and Aeromagnetic Data of the Tecoripa Chart in Southeast Sonora, Mexico.

    NASA Astrophysics Data System (ADS)

    Martínez-Retama, S.; Montaño-Del Cid, M. A.

    2015-12-01

    The Tecoripa chart H12-D64 is located southeast of the state of Sonora, México, south of Arizona. The geology is represented by sedimentary rocks of the Ordovician and Triassic, volcanic rocks of the Upper Cretaceous and Tertiary, intrusive rocks from the Upper Cretaceous- Tertiary and sedimentary rocks of the Cenozoic. In this paper a gravimetric study was conducted to determine the configuration and depth of the basement and to develop a structural model of the subsurface. For this purpose a consistent gravimetric survey in 3 profiles was conducted. To complement this study, gravimetric data obtained by INEGI (96 gravimetric stations spaced every 4000 m) that correspond to a regional survey was also used. The two sets of data were corrected and processed with the WinGLink software. The profiles were then modeled using the Talwani method. 4 Profiles corresponding to the gravimetric survey and 5 data profiles from INEGI were modeled. Aeromagnetic data from the total field of Tecoripa chart were also processed. The digital information was integrated and processed by generating a data grid. Processes applied to data consisted of reduction to the pole, regional-residual separation and upward continuations. In general, the obtained structural models show intrusive bodies associated with well-defined high gravimetric and magnetic and low gravimetric and magnetic are associated with basins and sedimentary rocks. The obtained geological models show the basement represented by volcanic rocks of the Tarahumara Formation from the Upper Cretaceous which are in contact with sedimentary rocks from the Barranca Group from Upper Cretaceous and limestones from the Middle Ordovician. Both volcanic and sedimentary rocks are intruded by granodiorite- granite with ages of the Tertiary-Oligocene. Based on the superficial geology as well as in the configuration of the basement and the obtained structural model the existence of faults with NW-SE orientation that originate Horst and

  2. High resolution imaging of the Methana volcanic complex, Greece, with magnetotelluric and aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Efstathiou, A.; Tzanis, A.; Chailas, S.; Lagios, E.; Stamatakis, M.

    2012-04-01

    The Methana calc-alkaline volcanic complex is located off the NE coast of Argolis Peninsula (Peloponnesus, Greece) at the NW terminus of the Hellenic Volcanic Arc (HVA). It consists of approximately 32 domes, with the most recent eruptive episodes dated to 258 BCE and 1700 CE. Herein, we report the results an attempt to investigate the volcano's interior with joint interpretation of Magnetotelluric and Aeromagnetic data. The aeromagnetic data was inverted with the UBC-GIF 3D magnetic inversion suite, constrained by several in-situ susceptibility measurements. At depths to 2 km, the inversion resolves individual intrusions corresponding to known phases of volcanic activity (domes), with susceptibilities >0.1. At depths greater than 4.5 km, a more weakly magnetized domain is detected (~0.025); its ceiling is well resolved; its floor cannot be placed with certainty but extends to at least 7 km. The depths are comparable to those of magma chambers. Based on the palaeomagnetic analysis of nearby volcanic rocks, it may be safely suggested that its temperature should not be higher than 550-600°C, but also not considerably lower. It may comprise a magma chamber, inasmuch as it compares well with the temperatures and locations of known magma chambers along the HVA. Finally, there's exists evidence of the location of the vents through which the extrusive activity has taken place. A Magnetotelluric survey comprising 14 stations was conducted IN 1992, as part of a geothermal project. Herein, this data is reevaluated with modern analysis methods and re-interpreted with 2D inversion. The results indicate the presence of conductors at depths of 1500-2500 m beneath the centre of the Peninsula, extensive horizontal conductors at, or just below sea level and conductive protrusions above sea level. The joint interpretation of the susceptibility and geoelectric images is based on the premise that they both are generated by hydrothermal circulation which depresses resistivity and

  3. 14 CFR 417.233 - Analysis for an unguided suborbital launch vehicle flown with a wind weighting safety system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... vehicle flown with a wind weighting safety system. 417.233 Section 417.233 Aeronautics and Space... with a wind weighting safety system. For each launch of an unguided suborbital launch vehicle flown with a wind weighting safety system, in addition to the other requirements in this subpart outlined...

  4. 14 CFR 417.233 - Analysis for an unguided suborbital launch vehicle flown with a wind weighting safety system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... vehicle flown with a wind weighting safety system. 417.233 Section 417.233 Aeronautics and Space... with a wind weighting safety system. For each launch of an unguided suborbital launch vehicle flown with a wind weighting safety system, in addition to the other requirements in this subpart outlined...

  5. 14 CFR 417.233 - Analysis for an unguided suborbital launch vehicle flown with a wind weighting safety system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... vehicle flown with a wind weighting safety system. 417.233 Section 417.233 Aeronautics and Space... with a wind weighting safety system. For each launch of an unguided suborbital launch vehicle flown with a wind weighting safety system, in addition to the other requirements in this subpart outlined...

  6. 14 CFR 417.233 - Analysis for an unguided suborbital launch vehicle flown with a wind weighting safety system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... vehicle flown with a wind weighting safety system. 417.233 Section 417.233 Aeronautics and Space... with a wind weighting safety system. For each launch of an unguided suborbital launch vehicle flown with a wind weighting safety system, in addition to the other requirements in this subpart outlined...

  7. 14 CFR 417.233 - Analysis for an unguided suborbital launch vehicle flown with a wind weighting safety system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... vehicle flown with a wind weighting safety system. 417.233 Section 417.233 Aeronautics and Space... with a wind weighting safety system. For each launch of an unguided suborbital launch vehicle flown with a wind weighting safety system, in addition to the other requirements in this subpart outlined...

  8. Location, structure, and seismicity of the Seattle fault zone, Washington: Evidence from aeromagnetic anomalies, geologic mapping, and seismic-reflection data

    USGS Publications Warehouse

    Blakely, R.J.; Wells, R.E.; Weaver, C.S.; Johnson, S.Y.

    2002-01-01

    A high-resolution aeromagnetic survey of the Puget Lowland shows details of the Seattle fault zone, an active but largely concealed east-trending zone of reverse faulting at the southern margin of the Seattle basin. Three elongate, east-trending magnetic anomalies are associated with north-dipping Tertiary strata exposed in the hanging wall; the magnetic anomalies indicate where these strata continue beneath glacial deposits. The northernmost anomaly, a narrow, elongate magnetic high, precisely correlates with magnetic Miocene volcanic conglomerate. The middle anomaly, a broad magnetic low, correlates with thick, nonmagnetic Eocene and Oligocene marine and fluvial strata. The southern anomaly, a broad, complex magnetic high, correlates with Eocene volcanic and sedimentary rocks. This tripartite package of anomalies is especially clear over Bainbridge Island west of Seattle and over the region east of Lake Washington. Although attenuated in the intervening region, the pattern can be correlated with the mapped strike of beds following a northwest-striking anticline beneath Seattle. The aeromagnetic and geologic data define three main strands of the Seattle fault zone identified in marine seismic-reflection profiles to be subparallel to mapped bedrock trends over a distance of >50 km. The locus of faulting coincides with a diffuse zone of shallow crustal seismicity and the region of uplift produced by the M 7 Seattle earthquake of A.D. 900-930.

  9. Aeromagnetic map of the Fossil Springs Roadless Area, Yavapai, Gila, and Coconino counties, Arizona

    USGS Publications Warehouse

    Davis, W.E.; Weir, G.W.

    1984-01-01

    The magnetic anomalies and patterns on the aeromagnetic map reflect variations of magnetization in the underlying rocks. Basaltic rocks contain moderate amounts of magnetic minerals, mainly magnetite, and possess strong intensities of magnetization. The more silicic volcanic rocks have much lower magnetization intensities. Sedimentary rocks contain little or no magnetite and are virtually nonmagnetic.

  10. Aeromagnetic Map with Geology of the Los Angeles 30 x 60 Minute Quadrangle, Southern California

    USGS Publications Warehouse

    Langenheim, V.E.; Hildenbrand, T.G.; Jachens, R.C.; Campbell, R.H.; Yerkes, R.F.

    2006-01-01

    Introduction: An important objective of geologic mapping is to project surficial structures and stratigraphy into the subsurface. Geophysical data and analysis are useful tools for achieving this objective. This aeromagnetic anomaly map provides a three-dimensional perspective to the geologic mapping of the Los Angeles 30 by 60 minute quadrangle. Aeromagnetic maps show the distribution of magnetic rocks, primarily those containing magnetite (Blakely, 1995). In the Los Angeles quadrangle, the magnetic sources are Tertiary and Mesozoic igneous rocks and Precambrian crystalline rocks. Aeromagnetic anomalies mark abrupt spatial contrasts in magnetization that can be attributed to lithologic boundaries, perhaps caused by faulting of these rocks or by intrusive contacts. This aeromagnetic map overlain on geology, with information from wells and other geophysical data, provides constraints on the subsurface geology by allowing us to trace faults beneath surficial cover and estimate fault dip and offset. This map supersedes Langenheim and Jachens (1997) because of its digital form and the added value of overlaying the magnetic data on a geologic base. The geologic base for this map is from Yerkes and Campbell (2005); some of their subunits have been merged into one on this map.

  11. Phase Preserving Dynamic Range Compression of Aeromagnetic Images

    NASA Astrophysics Data System (ADS)

    Kovesi, Peter

    2014-05-01

    Geoscientific images with a high dynamic range, such as aeromagnetic images, are difficult to present in a manner that facilitates interpretation. The data values may range over 20000 nanoteslas or more but a computer monitor is typically designed to present input data constrained to 8 bit values. Standard photographic high dynamic range tonemapping algorithms may be unsuitable, or inapplicable to such data because they are have been developed on the basis of statistics of natural images, feature types found in natural images, and models of the human visual system. These algorithms may also require image segmentation and/or decomposition of the image into base and detail layers but these operations may have no meaning for geoscientific images. For geological and geophysical data high dynamic range images are often dealt with via histogram equalization. The problem with this approach is that the contrast stretch or compression applied to data values depends on how frequently the data values occur in the image and not on the magnitude of any data features themselves. This can lead to inappropriate distortions in the output. Other approaches include use of the Automatic Gain Control algorithm developed by Rajagopalan, or the tilt derivative. A difficulty with these approaches is that the signal can be over-normalized and perception of the overall variations in the signal can be lost. To overcome these problems a method is presented that compresses the dynamic range of an image while preserving local features. It makes no assumptions about the formation of the image, the feature types it contains, or its range of values. Thus, unlike algorithms designed for photographic images, this algorithm can be applied to a wide range of scientific images. The method is based on extracting local phase and amplitude values across the image using monogenic filters. The dynamic range of the image can then be reduced by applying a range reducing function to the amplitude values, for

  12. Altered carbohydrate, lipid, and xenobiotic metabolism by liver from rats flown on Cosmos 1887

    NASA Technical Reports Server (NTRS)

    Merrill, A. H. Jr; Hoel, M.; Wang, E.; Mullins, R. E.; Hargrove, J. L.; Jones, D. P.; Popova, I. A.; Merrill AH, J. r. (Principal Investigator)

    1990-01-01

    To determine the possible biochemical effects of prolonged weightlessness on liver function, samples of liver from rats that had flown aboard Cosmos 1887 were analyzed for protein, glycogen, and lipids as well as the activities of a number of key enzymes involved in metabolism of these compounds and xenobiotics. Among the parameters measured, the major differences were elevations in the glycogen content and hydroxymethylglutaryl-CoA (HMG-CoA) reductase activities for the rats flown on Cosmos 1887 and decreases in the amount of microsomal cytochrome P-450 and the activities of aniline hydroxylase and ethylmorphine N-demethylase, cytochrome P-450-dependent enzymes. These results support the earlier finding of differences in these parameters and suggest that altered hepatic function could be important during spaceflight and/or the postflight recovery period.

  13. Mutations in cauliflower and sprout broccoli grown from seeds flown in space

    NASA Astrophysics Data System (ADS)

    Wu, Hong; Huang, Congli; Zhang, Keping; Sun, Yeqing

    2010-11-01

    Cauliflower and sprout broccoli are widely planted vegetables particularly in Fujian Province, China. To study the mutation in these two types of vegetables induced from spaceflight, we flew the seeds on the 20th Chinese recoverable satellite which orbited the Earth for 18 days. After returning to the Earth, the cauliflower seeds were planted for two generations and the sprout broccoli seeds for one generation at the Xiamen Agriculture Research Institute. Of the 12 cauliflowers planted for the first generation, two showed significant phenotypical changes in both the size of the plant and the weight of the flower head. In addition, most of the space flown plants were found to be resistant to the black rot attack in the field. Cauliflowers planted for the second generation from the seeds in one of the two plants that displayed phenotypical changes in the first generation showed similar mutations. For the first generation of sprout broccoli, the rate of emergence from the flown seeds was lower than that of the control by 30%. No significant changes in the phenotype between the sprout broccolis planted from the flown seeds and the control were observed except one of the mutated sprout broccolis showed a change in the appearance in the lesser bud of the chief flower head. Results of the study demonstrated that DNA damages in some of the genes may have occurred in the seeds flown in space, and some of the changes in the genes may have inherited from the first to the second generation. The improved resistance to the black rot attack and increased size of the flower head are apparently beneficial.

  14. Inhibited interferon-gamma but normal interleukin-3 production from rats flown on the space shuttle.

    PubMed

    Gould, C L; Lyte, M; Williams, J; Mandel, A D; Sonnenfeld, G

    1987-10-01

    Rats were flown on Space Shuttle SL-3 for 1 week. When spleen cells were removed from these rats and challenged with concanavalin-A, interferon-gamma production was severely inhibited, while interleukin-3 production was unaffected compared to ground-based control rats. These data indicate that there is a defect in interferon-gamma production in rats that have been exposed to spaceflight. This defect could contribute to, and be one reason for, immunosuppression observed after spaceflight.

  15. Inhibited interferon-gamma but normal interleukin-3 production from rats flown on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Gould, Cheryl L.; Lyte, Mark; Williams, Joann; Mandel, Adrian D.; Sonnenfeld, Gerald

    1987-01-01

    Rats were flown on Space Shuttle SL-3 for one week. When spleen cells were removed from these rats and challenged with concanavalin-A, interferon-gamma production was severely inhibited, while interleukin-3 production was unaffected compared to ground-based control rats. These data indicate that there is a defect in interferon-gamma production in rats that have been exposed to spaceflight. This defect could contribute to, and be one reason for, immunosuppression observed after spaceflight.

  16. Effects of atomic oxygen on polymeric materials flown on EOIM-3

    NASA Technical Reports Server (NTRS)

    Kamenetzky, Rachel R.; Linton, Roger C.; Finckenor, Miria M.; Vaughn, Jason A.

    1995-01-01

    Diverse polymeric materials, including several variations of Kapton, were flown on STS-46 as part of the Evaluation of Oxygen Interaction with Materials Experiment (EOIM-3). These materials were flown in the cargo bay and exposed to the space environment July 31 - August 8, 1992, including 40 hours of direct atomic oxygen impingement. The atomic oxygen exposure was approximately 2.2 x 10(exp 20) atoms/sq cm. Polymeric materials flown on EOIM-3 include coated and uncoated Kapton, Tefzel ETFE, Lexan, FEP and TFE Teflon, bulk Halar and PEEK, S383 silicone and Viton elastomeric seal material. Analyses performed included thickness measurements using Dektak and eddy current methods, mass loss, resistance, permeability, hardness, and FTIR. The effects of stress and the space environment on Kapton were also evaluated. Previous EOIM missions on STS-5 and STS-8 and the Long Duration Exposure Facility also contained polymeric material samples. Data from these previous flights are shown for comparison, as well as ground simulation of space environment effects using both thermal energy flow tubes and 5 eV neutral atomic oxygen beam facilities. Reaction efficiencies for the various atomic oxygen exposure conditions are discussed.

  17. Aeromagnetic expression of faults that offset basin fill, Albuquerque basin, New Mexico

    USGS Publications Warehouse

    Grauch, V.J.S.; Hudson, M.R.; Minor, S.A.

    2001-01-01

    High-resolution aeromagnetic data acquired over the Albuquerque basin show widespread expression of faults that offset basin fill and demonstrate that the aeromagnetic method can be an important hydrogeologic and surficial mapping tool in sediment-filled basins. Aeromagnetic expression of faults is recognized by the common correspondence of linear anomalies to surficial evidence of faulting across the area. In map view, linear anomalies show patterns typical of extensional faulting, such as anastomosing and en echelon segments. Depths to the tops of faulted magnetic layers showing the most prominent aeromagnetic expression range from 0 to 100 m. Sources related to subtler fault expressions range in depths from 200 to 500 m. We estimate that sources of the magnetic expressions of the near-surface faults likely reside within the upper 500-600 m of the subsurface. The linear anomalies in profile form show a range of shapes, but all of them can be explained by the juxta-position of layers having different magnetic properties. One typical anomaly differs from the expected symmetric fault anomaly by exhibiting an apparent low over the fault zone and more than one inflection point. Although the apparent low could easily be misinterpreted as representing multiple faults or an anomalous fault zone, geophysical analysis, magnetic-property measurements, and geologic considerations lead instead to a "thin-thick model" in which magnetic layers of different thickness are juxtaposed. The general geometry of this model is a thin magnetic layer on the upthrown block and a thick magnetic layer on the downthrown block. The thin-thick model can be represented geologically by growth faulting and syntectonic sedimentation, where relatively coarse-grained sediment (which is more magnetic than fine-grained material) has accumulated in the hanging wall. This implies that the aeromagnetic data have potential for mapping growth faults and locating concentrations of coarse-grained material

  18. Aeromagnetic and radio echo ice-sounding measurements show much greater area of the dufek intrusion, antarctica.

    PubMed

    Behrendt, J C; Drewry, D J; Jankowski, E; Grim, M S

    1980-08-29

    A combined aeromagnetic and radio echo ice-sounding survey made in 1978 in Antarctica over the Dufek layered mafic intrusion suggests a minimum area of the intrusion of about 50,000 square kilometers, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and subglacial topographic profiles illustrate the usefulness of this combination of methods in studying bedrock geology beneath ice-covered areas. Magnetic anomalies range in peak-to-through amplitude from about 50 nanoteslas over the lowermost exposed portion of the section in the Dufek Massif to about 3600 nanoteslas over the uppermost part of the section in the Forrestal Range. Theoretical magnetic anomalies, computed from a model based on the subice topography fitted to the highest amplitude observed magnetic anomalies, required normal and reversed magnetizations ranging from 10(-3) to 10(-2) electromagnetic units per cubic centimeter. This result is interpreted as indicating that the Dufek intrusion cooled through the Curie isotherm during one or more reversals of the earth's magnetic field.

  19. Aeromagnetic and radio echo ice-sounding measurements show much greater area of the Dufek intrusion, Antarctica

    USGS Publications Warehouse

    Behrendt, John C.; Drewry, D.J.; Jankowski, E.; Grim, M.S.

    1980-01-01

    A combined aeromagnetic and radio echo ice-sounding survey made in 1978 in Antarctica over the Dufek layered mafic intrusion suggests a minimum area of the intrusion of about 50,000 square kilometers, making it comparable in size with the Bushveld Complex of Africa. Comparisons of the magnetic and subglacial topographic profiles illustrate the usefulness of this combination of methods in studying bedrock geology beneath ice-covered areas. Magnetic anomalies range in peak-to-trough amplitude from about 50 nanoteslas over the lowermost exposed portion of the section in the Dufek Massif to about 3600 nanoteslas over the uppermost part of the section in the Forrestal Range. Theoretical magnetic anomalies, computed from a model based on the subice topography fitted to the highest amplitude observed magnetic anomalies, required normal and reversed magnetizations ranging from 10-3 to 10-2 electromagnetic units per cubic centimeter. This result is interpreted as indicating that the Dufek intrusion cooled through the Curie isotherm during one or more reversals of the earth's magnetic field. Copyright ?? 1980 AAAS.

  20. Simulator evaluation of manually flown curved instrument approaches. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Sager, D.

    1973-01-01

    Pilot performance in flying horizontally curved instrument approaches was analyzed by having nine test subjects fly curved approaches in a fixed-base simulator. Approaches were flown without an autopilot and without a flight director. Evaluations were based on deviation measurements made at a number of points along the curved approach path and on subject questionnaires. Results indicate that pilots can fly curved approaches, though less accurately than straight-in approaches; that a moderate wind does not effect curve flying performance; and that there is no performance difference between 60 deg. and 90 deg. turns. A tradeoff of curve path parameters and a paper analysis of wind compensation were also made.

  1. Transmittance measurements of ultra violet and visible wavelength interference filters flown aboard LDEF

    NASA Technical Reports Server (NTRS)

    Mooney, Thomas A.; Smajkiewicz, Ali

    1991-01-01

    A set of ten interference filters for the UV and VIS spectral region were flown on the surface of the Long Duration Exposure Facility (LDEF) Tray B-8 along with earth radiation budget (ERB) components from the Eppley Laboratory. Transmittance changes and other degradation observed after the return of the filters to Barr are reported. Substrates, coatings, and (where applicable) cement materials are identified. In general, all filters except those containing lead compounds survived well. Metal dielectric filters for the UV developed large numbers of pinholes which caused an increase in transmittance. Band shapes and spectral positioning, however, did not change.

  2. Analyses of plasma for metabolic and hormonal changes in rats flown aboard Cosmos 2044

    NASA Technical Reports Server (NTRS)

    Merrill, Alfred H., Jr.; Wang, Elaine; Mullins, Richard E.; Grindeland, Richard E.; Popova, Irina A.

    1992-01-01

    Plasmas samples from rats flown aboard Cosmos 2044 were analyzed for the levels of key metabolites, electrolytes, enzymes, and hormones. The major differences between the flight group and the synchronous control were elevations in glucose, cholesterol, phosphate, creatinine, blood urea nitrogen, lactate dehydrogenase, and aspartate aminotransferase and decreased levels of thyroxine. Most of these differences were not mimicked by tail suspension of ground-based rats; however, both flight and suspended rats exhibited inhibited testosterone secretion. Corticosterone, immunoreactive growth hormone, and prolactin showed inconsistent differences from the various control groups, suggesting that the levels of these hormones were not due to actual or simulated microgravity.

  3. The Greatest Missions Never Flown: Anticipatory Discourse and the "Projectory" in Technological Communities.

    PubMed

    Messeri, Lisa; Vertesi, Janet

    2015-01-01

    This article introduces the concept of the sociotechnical projectory to explore the importance of future-oriented discourse in technical practice. It examines the case of two flagship NASA missions that, since the 1960s, have been continually proposed and deferred. Despite the missions never being flown, it argues that they produced powerful effects within the planetary science community as assumed "end-points" to which all current technological, scientific, and community efforts are directed. It asserts that attention to the social construction of technological systems requires historical attention to how actors situate themselves with respect to a shared narrative of the future.

  4. The Greatest Missions Never Flown: Anticipatory Discourse and the "Projectory" in Technological Communities.

    PubMed

    Messeri, Lisa; Vertesi, Janet

    2015-01-01

    This article introduces the concept of the sociotechnical projectory to explore the importance of future-oriented discourse in technical practice. It examines the case of two flagship NASA missions that, since the 1960s, have been continually proposed and deferred. Despite the missions never being flown, it argues that they produced powerful effects within the planetary science community as assumed "end-points" to which all current technological, scientific, and community efforts are directed. It asserts that attention to the social construction of technological systems requires historical attention to how actors situate themselves with respect to a shared narrative of the future. PMID:26334697

  5. Problems in analysis of data from muscles of rats flown in space

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Henriksen, E.; Jacob, S.; Satarug, S.; Cook, P.

    1988-01-01

    Comparison of hindlimb muscles of rats flown on Spacelab-3 or tail-traction-suspended showed that 11-17 h reloading post-flight might have altered the results. Soleus atrophied, plantaris, gastrocnemius and extensor digitorum longus grew slower, and tibialis anterior grew normally. In both flight and simulated soleus and plantaris, higher tyrosine and greater glutamine/glutamate ratio indicated negative protein balance and increased glutamine production, respectively, relative to controls. Aspartate was lower in these muscles. Reloading generally decreased tyrosine, but increased aspartate and glutamine/glutamate. These data showed that at 12 h of reloading after flight is characterized by reversal to varying extents of effects of unloading.

  6. Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite

    NASA Technical Reports Server (NTRS)

    Cronin, A. G.; Delaney, J. R.

    1973-01-01

    The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system.

  7. Use of remote sensing techniques and aeromagnetic data to study episodic oil seep discharges along the Gulf of Suez in Egypt.

    PubMed

    Kaiser, M F; Aziz, A M; Ghieth, B M

    2013-07-15

    Four successive oil discharges were observed during the last 2 years following the recording of the earthquake events. Oil slicks were clearly observed in the thermal band of the Enhanced Thematic Mapper images acquired during the discharge events. Lineaments were extracted from the ETM+ image data and SRTM (DEM). The seismic activity is conformable in time and spatially related to active major faults and structural lineaments. The concerned site was subjected to a numerous earthquakes with magnitudes ranging from 3 to 5.4 Mb. Aeromagnetic field data analyses indicated the existence of deep major faults crossing the Gebel El-Zeit and the Mellaha basins (oil reservoirs). The magnetic field survey showed major distinctive fault striking NE-SW at 7000 m depth. Occurrence of these faults at great depth enables the crude oil to migrate upward and appear at the surfaces as oil seeps onshore and as offshore slicks in the Gemsa-Hurghada coastal zone. PMID:23688834

  8. Use of remote sensing techniques and aeromagnetic data to study episodic oil seep discharges along the Gulf of Suez in Egypt.

    PubMed

    Kaiser, M F; Aziz, A M; Ghieth, B M

    2013-07-15

    Four successive oil discharges were observed during the last 2 years following the recording of the earthquake events. Oil slicks were clearly observed in the thermal band of the Enhanced Thematic Mapper images acquired during the discharge events. Lineaments were extracted from the ETM+ image data and SRTM (DEM). The seismic activity is conformable in time and spatially related to active major faults and structural lineaments. The concerned site was subjected to a numerous earthquakes with magnitudes ranging from 3 to 5.4 Mb. Aeromagnetic field data analyses indicated the existence of deep major faults crossing the Gebel El-Zeit and the Mellaha basins (oil reservoirs). The magnetic field survey showed major distinctive fault striking NE-SW at 7000 m depth. Occurrence of these faults at great depth enables the crude oil to migrate upward and appear at the surfaces as oil seeps onshore and as offshore slicks in the Gemsa-Hurghada coastal zone.

  9. Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California. Report on work done from December 1, 1980-May 31, 1981

    SciTech Connect

    Couch, R.; Gemperle, M.

    1982-01-01

    Spectral analysis of aeromagnetic data collected over north-central California during the summer of 1980 aided in determining magnetic-source bottom depths beneath the survey area. Five regions of shallow magnetic source bottom depths were detected: (1) Secret Spring Mountain and National Lava Beds Monument area; (2) the Mount Shasta area; (3) the Eddys Mountain area; (4) the Big Valley Mountains area; and (5) an area northeast of Lassen Peak. Except for the Eddys Mountain area, all regions exhibiting shallow depths are suggested to be due to elevated Curie-point isotherms. Deeper magnetic source bottom depths were mapped throughout the remainder of the study area, with depths greater than 9 km BSL indicated beneath Lassen Peak and greater than 11 km BSL indicated beneath the Western Cascades, Eastern Klamath Mountains, and Great Valley.

  10. Aeromagnetic legacy of early Paleozoic subduction along the Pacific margin of Gondwana

    USGS Publications Warehouse

    Finn, C.; Moore, D.; Damaske, D.; Mackey, T.

    1999-01-01

    Comparison of the aeromagnetic signatures and geology of southeastern Australia and northern Victoria Land, Antarctica, with similar data from ancient subduction zones in California and Japan, provides a framework for reinterpretation of the plate tectonic setting of the Pacific margin of early Paleozoic Gondwana. In our model, the plutons in the Glenelg (south-eastern Australia) and Wilson (northern Victoria Land) zones formed the roots of continental-margin magmatic arcs. Eastward shifting of arc magmatism resulted in the Stavely (south-eastern Australia) and Bowers (northern Victoria Land) volcanic eruptions onto oceanic forearc crust. The turbidites in the Stawell (southeastern Australia) and Robertson Bay (northern Victoria Land zones) shed from the Glenelg and Wilson zones, respectively, were deposited along the trench and onto the subducting oceanic plate. The margin was subsequently truncated by thrust faults and uplifted during the Delamerian and Ross orogenies, leading to the present-day aeromagnetic signatures.

  11. Magnetic Properties of Quaternary Deposits, Kenai Peninsula, Alaska -- Implications for Aeromagnetic Anomalies of Upper Cook Inlet

    USGS Publications Warehouse

    Saltus, R.W.; Haeussler, P.J.

    2004-01-01

    We measured magnetic susceptibilities of exposed Quaternary deposits on several beach cliffs and river banks on the Kenai Peninsula near Soldotna, Alaska. Data, descriptions, and photos from nine sites are included in this report. The mean susceptibility for Quaternary materials in this region is approximately 2.5 x 10-3 SI units. This is sufficiently magnetic to produce subtle aeromagnetic anomalies such as those observed to correlate with topographic features in the region of the measurements. The highest susceptibilities measured (greater than 20 x 10-3 SI units) may help, at least in part, to explain moderate amplitude aeromagnetic anomalies observed elsewhere in Cook Inlet, particularly those relating to structures showing Quaternary movement. Comparison of measured beach cliff susceptibility and susceptibility predicted from idealized formulas and two-dimensional cliff models suggests that measured susceptibilies underestimate true bulk susceptibility by 20 percent to 50 percent in this region.

  12. Aeromagnetic search for Cenozoic magmatism over the Admiralty Mountains Block (East Antarctica)

    USGS Publications Warehouse

    ,; ,; Ferraccioli, F.; Zunino, A.; Bozzo, E.; Rocchi, S.; Armienti, P.

    2007-01-01

    Cenozoic magmatic rocks of the Transantarctic Mountains provide an important window on the tectonic and magmatic processes of the West Antarctic Rift System. Previous aeromagnetic investigations in northern Victoria Land have delineated Cenozoic volcanic and intrusive complexes assigned to the McMurdo Volcanic Group and Meander Intrusives over the Transantarctic Mountains. We present a new aeromagnetic anomaly map for the region north of the Mariner Glacier to study the extent and spatial distribution of these Cenozoic rocks over the previously unexplored Admiralty Mountains. The new map shows that the Meander Intrusives are restricted to the coastal region between the Malta Plateau and the Daniell Peninsula. However, the McMurdo Volcanic Group rocks extend further inland, and may delineate a hitherto unrecognised volcano-tectonic rift zone, extending as far north as the Trafalgar Glacier.

  13. Basement influence on the structural geology of southern Oklahoma inferred from residual aeromagnetic maps

    SciTech Connect

    Thompson. T.L. ); Gay, S.P. ); Hawley, B.; Howe, J.R.

    1991-08-01

    This poster display illustrates magnetic basement control on the structural pattern of southern Oklahoma with a few examples of its influence on petroleum accumulation, including potential fracture reservoirs (i.e., Arbuckle, Viola-Bigfork, Woodford-Arkansas novaculite formations etc.). Exploration for fractured petroleum reservoirs requires knowledge of structural dynamics, structural mechanics, and present state of stress as well as paleostress. High-resolution residual aeromagnetic mapping provides a particularly useful display of areal continuity of basement block pattern that, when considered in context of tectonic plate movements, allows predictions of specific fault reactivation, timing, and sense of displacement. Study of aeromagnetics often provides better understanding, downward and lateral projection of known faults, support for suspected faults, and inference of previously unrecognized faults.

  14. Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska

    USGS Publications Warehouse

    Saltus, R.W.; Potter, C.J.; Phillips, J.D.

    2006-01-01

    Aeromagnetic and gravity data are processed and interpreted to reveal deep and shallow information about the crustal structure of the central North Slope, Alaska. Regional aeromagnetic anomalies primarily reflect deep crustal features. Regional gravity anomalies are more complex and require detailed analysis. We constrain our geophysical models with seismic data and interpretations along two transects including the Trans-Alaska Crustal Transect. Combined geophysical analysis reveals a remarkable heterogeneity of the pre-Mississippian basement. In the central North Slope, pre-Mississippian basement consists of two distinct geophysical domains. To the southwest, the basement is dense and highly magnetic; this basement is likely mafic and mechanically strong, possibly acting as a buttress to basement involvement in Brooks Range thrusting. To the northeast, the central North Slope basement consists of lower density, moderately magnetic rocks with several discrete regions (intrusions?) of more magnetic rocks. A conjugate set of geophysical trends, northwest-southeast and southwest-northeast, may be a factor in the crustal response to tectonic compression in this domain. High-resolution gravity and aeromagnetic data, where available, reflect details of shallow fault and fold structure. The maps and profile models in this report should provide useful guidelines and complementary information for regional structural studies, particularly in combination with detailed seismic reflection interpretations. Future challenges include collection of high-resolution gravity and aeromagnetic data for the entire North Slope as well as additional deep crustal information from seismic, drilling, and other complementary methods. Copyrights ?? 2006. The American Association of Petroleum Geologists. All rights reserved.

  15. Aeromagnetic and Gravity Maps of the Central Marysvale Volcanic Field, Southwestern Utah

    USGS Publications Warehouse

    Campbell, David L.; Steven, Thomas A.; Cunningham, Charles G.; Rowley, Peter D.

    1999-01-01

    Gravity and aeromagnetic features in the Marysvale volcanic field result from the composite effects of many factors, including rock composition, style of magmatic emplacement, type and intensity of rock alteration, and effects of structural evolution. Densities and magnetic properties measured on a suite of rock samples from the Marysvale volcanic field differ in systematic ways. Generally, the measured densities, magnetic susceptibilities, and natural remanent magnetizations all increase with mafic index, but decrease with degree of alteration, and for tuffs, with degree of welding. Koenigsberger Q indices show no such systematic trends. The study area is divided into three geophysical domains. The northern domain is dominated by aeromagnetic lows that probably reflect reversed-polarity volcanic flows. There are no intermediate-sized magnetic highs in the northern domain that might reflect plutons. The northern domain has a decreasing-to-the-south gravity gradient that reflects the Pavant Range homocline. The central domain has gravity lows that reflect altered rocks in calderas and low-density plutons of the Marysvale volcanic field. Its aeromagnetic signatures consist of rounded highs that reflect plutons and birdseye patterns that reflect volcanic flows. In many places the birdseyes are attenuated, indicating that the flows there have been hydrothermally altered. We interpret the central domain to reflect an east-trending locus of plutons in the Marysvale volcanic field. The southern domain has intermediate gravity fields, indicating somewhat denser rocks there than in the central domain, and high-amplitude aeromagnetic birdseyes that reflect unaltered volcanic units. The southern domain contains no magnetic signatures that we interpret to reflect plutons. Basin-and-range tectonism has overprinted additional gravity features on the three domains. A deep gravity low follows the Sevier and Marysvale Valleys, reflecting grabens there. The gravity gradient in the

  16. Profiles of gamma-ray and magnetic data for aerial surveys over parts of the Western United States from longitude 108 to 126 degrees W. and from latitude 34 to 49 degrees N.

    USGS Publications Warehouse

    Duval, Joseph S.

    1995-01-01

    This CD-ROM contains images generated from geophysical data, software for displaying and analyzing the images and software for displaying and examining profile data from aerial surveys flown as part of the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy. The images included are of gamma-ray data (uranium, thorium, and potassium channels), Bouguer gravity data, isostatic residual gravity data, aeromagnetic anomalies, topography, and topography with bathymetry. This publication contains image data for the conterminous United States and profile data for the conterminous United States within the area longitude 108 to 126 degrees W. and latitude 34 to 49 degrees N. The profile data include apparent surface concentrations of potassium, uranium, and thorium, the residual magnetic field, and the height above the ground. The images on this CD-ROM include graytone and color images of each data set, color shaded-relief images of the potential-field and topographic data, and color composite images of the gamma-ray data. The image display and analysis software can register images with geographic and geologic overlays. The profile display software permits the user to view the profiles as well as obtain data listings and export ASCII versions of data for selected flight lines.

  17. Aeromagnetic anomalies uncover the Precambrian basement in the Chhattisgarh basin area, Central India

    NASA Astrophysics Data System (ADS)

    Ram, Bahadur; Singh, Nagendra; Murthy, A.

    2008-12-01

    This paper presents aeromagnetic images for the Chhattisgarh basin region, in Central India, to provide a new window on Precambrian basement geology and structure. On the basis of aeromagnetic patterns, the Chhattisgarh basin is sub-divided into a northern low (negative) anomaly zone and a southern high (positive) anomaly zone. The northern portion of the main Chhattisgarh basin has been further divided into two subbasins, the Hirri sub-basin in the west, and Baradwar sub-basin in the east. A prominent negative anomaly delineates a NW-SE trending greenstone belt separating these sub-basins. Positive magnetic anomalies delineate the extent of the Dongargarh granite and equivalents, while the weak magnetic anomaly in the southeast of the Dongargarh granite and equivalents reflect granulite gneisses of the Eastern Ghat Mobile Belt. By applying the reduced-to-the-equator filter we enhanced the possible magnetic sources and structural lineaments within the Chhattisgarh basin. A new sketch map of structural elements was then compiled from aeromagnetic interpretation over the Chhattisgarh basin area. It includes possible faults, folds and an inferred lithological boundary.

  18. The aeromagnetic method as a tool to identify Cenozoic magmatism in the West Antarctic Rift System beneath the West Antarctic Ice Sheet — A review; Thiel subglacial volcano as possible source of the ash layer in the WAISCORE

    NASA Astrophysics Data System (ADS)

    Behrendt, John C.

    2013-02-01

    The West Antarctic Ice Sheet (WAIS) flows through the volcanically active West Antarctic Rift System (WARS). The aeromagnetic method has been the most useful geophysical tool for identification of subglacial volcanic rocks, since 1959-64 surveys, particularly combined with 1978 radar ice-sounding. The unique 1991-97 Central West Antarctica (CWA) aerogeophysical survey covering 354,000 km2 over the WAIS, (5-km line-spaced, orthogonal lines of aeromagnetic, radar ice-sounding, and aerogravity measurements), still provides invaluable information on subglacial volcanic rocks, particularly combined with the older aeromagnetic profiles. These data indicate numerous 100->1000 nT, 5-50-km width, shallow-source, magnetic anomalies over an area greater than 1.2 × 106 km2, mostly from subglacial volcanic sources. I interpreted the CWA anomalies as defining about 1000 "volcanic centers" requiring high remanent normal magnetizations in the present field direction. About 400 anomaly sources correlate with bed topography. At least 80% of these sources have less than 200 m relief at the WAIS bed. They appear modified by moving ice, requiring a younger age than the WAIS (about 25 Ma). Exposed volcanoes in the WARS are < 34 Ma, but at least four are active. If a few buried volcanic centers are active, subglacial volcanism may well affect the WAIS regime. Aerogeophysical data (Blankenship et al., 1993, Mt. Casertz; Corr and Vaughan, 2008, near Hudson Mts.) indicated active subglacial volcanism. Magnetic data indicate a caldera and a surrounding "low" in the WAISCORE vicinity possibly the result of a shallow Curie isotherm. High heat flow reported from temperature logging in the WAISCORE (Conway et al., 2011; Clow, personal commun.) and a volcanic ash layer (Dunbar, 2012) are consistent with this interpretation. A subaerially erupted subglacial volcano, (Mt Thiel), about 100 km distant, may be the ash source. The present rapid changes resulting from global warming, could be

  19. Reduction of spermatogonia and testosterone in rat testes flown on Space Lab-3

    NASA Technical Reports Server (NTRS)

    Philpott, Delbert E.; Stevenson, J.; Black, S.; Sapp, W.; Williams, C.

    1986-01-01

    The effects of space flight on rat testes were investigated. The weight, spermatogonial cell count, and testosterone levels in six rats flown on Space Lab-3 were measured. It is observed that compared to ground control rats the average weight loss was 7.1 percent and the spermatogonial cell count decreased by 7.5 percent. The data reveal that the testosterone level for large control rats was 9.13 ng/ml and 0.31 ng/ml for flight rats; and 2.54 ng/ml and 0.233 ng/ml for smaller control and flight rats, respectively. It is noted that spermatogenesis and testosterone production are reduced during spaceflight.

  20. NRL-ATM extreme ultraviolet solar image TV monitor flown on Skylab

    NASA Technical Reports Server (NTRS)

    Crockett, W. R.; Purcell, J. D.; Schumacher, R. J.; Tousey, R.; Patterson, N. P.

    1977-01-01

    An instrument for recording extreme ultraviolet television images of the sun was flown in the Apollo Telescope Mount on Skylab. Solar radiation in the 171-630 A wavelength range, defined by the transmission band of three thin-film aluminum filters, was focused onto a p-quaterphenyl photon conversion layer by a platinum-coated mirror at normal incidence. The conversion layer was attached to the faceplate of a low light level SEC vidicon. An onboard video monitor enabled the Skylab crews to observe the images in real-time and to identify and follow the development of solar features. Images were also transmitted to the mission control center, where they were used in planning the ATM observing schedule.

  1. Changes in pituitary growth hormone cells prepared from rats flown on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Grindeland, R.; Hymer, W. C.; Farrington, M.; Fast, T.; Hayes, C.; Motter, K.; Patil, L.; Vasques, M.

    1987-01-01

    The effect of exposure to microgravity on pituitary gland was investigated by examining cells isolated from anterior pituitaries of rats flown on the 7-day Spacelab 3 mission and, subsequently, cultured for 6 days. Compared with ground controls, flight cells contained more intracellular growth hormone (GH); however, the flight cells released less GH over the 6-day culture period and after implantation into hypophysectomized rats than did the control cells. Compared with control rats, glands from large rats (400 g) contained more somatotrophs (44 percent compared with 37 percent in control rats); small rats (200 g) showed no difference. No major differences were found in the somatotroph ultrastructure (by TEM) or in the pattern of the immunoactive GH variants. However, high-performance liquid chromatography fractionation of culture media indicated that flight cells released much less of a biologically active high-molecular weight GH variant, suggesting that space flight may lead to secretory dysfunction.

  2. A comparative study of seminiferous tubular epithelium from rats flown on Cosmos 1887 and SL3

    NASA Technical Reports Server (NTRS)

    Sapp, Walter J.; Williams, Carol S.; Kato, K.; Philpott, Delbert E.; Stevenson, J.; Serova, L. V.

    1989-01-01

    Space flight, with its unique environmental constraints such as immobilization, decreased and increased pressures, and radiation, is known to affect testicular morphology and spermatogenesis. Among the several biological experiments and animals on board COSMOS 1887 Biosputnik flight were 10 rats, from which were collected testicular tissue. Average weights of flight tests were 6.4 pct. below that of the vivarium control when normalized for weight loss/100 grams body weight. Counts of surviving spermatogonia per tubule cross section indicated an average of 39 spermatogonia for flight animals, 40 for synchronous controls and 44 for the vivarium controls. Serum testosterone was significantly decreased when compared to basal controls but the decrease was not significant when compared in vivarium and synchronous control groups. The significant decrease in spermatogonia and the decrease in serum testosterone are similar to that in animals flown on Space Lab 3 (Challenger Shuttle).

  3. NRL-ATM extreme ultraviolet solar image TV monitor flown on Skylab.

    PubMed

    Crockett, W R; Patterson, N P; Purcell, J D; Schumacher, R J; Tousey, R

    1977-04-01

    An instrument for recording extreme ultraviolet television images of the sun was flown in the Apollo Telescope Mount on Skylab. Solar radiation in the 171-630 A wavelength range, defined by the transmission band of three thin-film aluminum filters, was focused onto a p-quaterphenyl photon conversion layer by a platinum-coated mirror at normal incidence. The conversion layer was attached to the faceplate of a low light level SEC vidicon. An onboard video monitor enabled the Skylab crews to observe the images in realtime and to identify and follow the development of solar features. Images were also transmitted to the mission control center, where they were used in planning the ATM observing schedule.

  4. Differences in glycogen, lipids, and enzymes in livers from rats flown on COSMOS 2044.

    PubMed

    Merrill, A H; Wang, E; LaRocque, R; Mullins, R E; Morgan, E T; Hargrove, J L; Bonkovsky, H L; Popova, I A

    1992-08-01

    Livers from rats flown aboard COSMOS 2044 were analyzed for protein, carbohydrate (glycogen), and lipids as well as the activities of a number of key enzymes involved in metabolism of these compounds and xenobiotics. The major differences between the flight group and the synchronous control were elevations in microsomal protein, liver glycogen content, tyrosine aminotransferase, and tryptophan oxygenase and reductions in sphingolipids and the rate-limiting enzyme of heme biosynthesis, delta-aminolevulinic acid synthase. These results provide further evidence that spaceflight has pronounced and diverse effects on liver function; however, some of the results with samples from COSMOS 2044 differed notably from those from previous spaceflights. This may be due to conditions of spaceflight and/or the postflight recovery period for COSMOS 2044.

  5. Differences in glycogen, lipids, and enzymes in livers from rats flown on Cosmos 2044

    NASA Technical Reports Server (NTRS)

    Merrill, Alfred H., Jr.; Wang, Elaine; Laroque, Regina; Mullins, Richard E.; Morgan, Edward T.; Hargrove, James L.; Bonkovsky, Herbert L.; Popova, Irina A.

    1992-01-01

    Livers from rats flown aboard Cosmos 2044 were analyzed for protein, carbohydrate (glycogen), and lipids as well as the activities of a number of key enzymes involved in metabolism of these compounds and xenobiotics. The major differences between the flight group and the synchronous control were elevations in microsomal protein, liver glycogen content, tyrosine aminotransferase, and tryptophan oxygenase and reductions in sphingolipids and the rate-limiting enzyme of heme biosynthesis delta-aminolevulinic acid synthase. These results provide further evidence that spaceflight has pronounced and diverse effects on liver function; however, some of the results with samples from Cosmos 2044 differed notably from those from previous spaceflights. This may be due to conditions of spaceflight and/or the postflight recovery period for Cosmos 2044.

  6. Mapping the Extent of the Lovejoy Basalt Beneath the Sacramento Valley, CA, Using Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Langenheim, V. E.; Sweetkind, D. S.; Springhorn, S.

    2014-12-01

    The Lovejoy Basalt is a distinctive Miocene (~16 Ma) unit that erupted from Thompson Peak in the northeast Sierra Nevada, flowed southwest across the Sierra Nevada into the Sacramento Valley. It crops out in a few places in Sacramento Valley: (1) near Chico and Oroville on the east side of the valley, (2) Orland Buttes on the west side, and (3) Putnam Peak, some 250 km southwest of Thompson Peak. The basalt is also encountered in drill holes, but its extent is not entirely known. The Lovejoy Basalt is strongly magnetic and, in general, reversely magnetized, making it an excellent target for aeromagnetic mapping. Recently acquired aeromagnetic data (flight line spacing 800 m at an altitude of 240 m) indicate a characteristic, sinuous, short-wavelength magnetic pattern associated with outcrops and known subcrops of Lovejoy Basalt. Filtering of these data to enhance negative, short-wavelength anomalies defines two large bands of negative anomalies that trend southwest of Chico and Oroville and appear to coalesce about 25 km north of Sutter Buttes. Another band of negative anomalies extends north of the junction roughly along the Sacramento River 40 km to Deer Creek. The anomalies become more subdued to the north, suggesting that the Lovejoy thins to the north. Aeromagnetic data also indicate a large subcrop of Lovejoy Basalt that extends 25 km north-northeast from exposures at Orland Buttes. Driller logs from gas and water wells confirm our mapping of Lovejoy within these areas. The sinuous magnetic lows are not continuous south of Sutter Buttes, but form isolated patches that are aligned in a north-south direction south of the concealed Colusa Dome to Putnam Peak and an east-west, 20-km-long band about 15 km south of Sutter Buttes. Other reversed anomalies in the Sacramento Valley coincide with volcanic necks in the Sutter Buttes and Colusa Dome; these produce semicircular anomalies that are distinct from those caused by the Lovejoy Basalt.

  7. VTEM airborne EM, aeromagnetic and gamma-ray spectrometric data over the Cerro Quema high sulphidation epithermal gold deposits, Panama

    NASA Astrophysics Data System (ADS)

    Kwan, Karl; Prikhodko, Alexander; Legault, Jean M. Plastow, Geoffrey C.; Kapetas, John; Druecker, Michael

    2016-03-01

    In March 2012, a helicopter-borne versatile time-domain electromagnetic (VTEM), magnetic and radiometric survey was flown over the Cerro Quema high sulphidation (HS) epithermal gold deposits and the surrounding area. The Cerro Quema deposits are located in the Azuero Peninsula, Panama, approximately 8 km east of Güerita. The gold mineralisation is associated with clay-pyrite alterations topped by an acid-leached resistive cap, and the principal ores are pyrite-rich sulphides located within mineralised vuggy silica rocks. The geophysical data over the Cerro Quema deposits have been analysed. The electromagnetic (EM) responses over the deposits are characterised by resistivity highs and chargeability lows, surrounded by resistivity lows and chargeability highs. Radiometric Th/K ratio highs and magnetic susceptibility lows are observed over the deposits. These geophysical signatures over the Cerro Quema deposits are characteristic responses from HS epithermal gold deposits. The success of the VTEM survey points to the applicability of the regional helicopter electromagnetic, magnetic and gamma-ray spectrometry (EM-Mag-Spec) surveys for the exploration of similar HS epithermal gold deposits to depths < 500 m in weathered terrains.

  8. Aeromagnetic study of the midcontinent gravity high of central United States

    USGS Publications Warehouse

    King, Elizabeth R.; Zietz, Isidore

    1971-01-01

    A composite map of detailed aeromagnetic surveys over the midcontinent gravity high provides coverage of the 600-mi-long buried belt of mafic rocks of the Keweenawan Series from their outcrop localities in Minnesota and Wisconsin through Iowa and Nebraska. A map of the subsurface extent of the mafic rocks, based on the intricate magnetic patterns, shows that the rocks form a long, semicontinuous block, averaging 40 mi wide and consisting mainly of a sequence of layered flows. This sequence is probably fault-bounded and has been tilted up along the margins, where the linearity of the anomalies indicates steeper dips. The associated clastic rocks, indicated by a smoother magnetic pattern, occur in basins along both sides of the mafic belt and in grabens and a series of axial basins on the upper surface of the block. The well-defined outliers of flows marginal to the main block and the truncation of some of the outermost flow units along a diagonal boundary striking at an angle to them suggest that the present boundaries of the block are postdepositional structural features. The basins and the edges of the block appear to have controlled later, largely vertical movement in the overlying Paleozoic and younger sedimentary cover. Calculated models based on coincident magnetic and detailed gravity profiles along typical cross sections of the midcontinent gravity high show that the block of mafic rocks is steep-sided and as much as several miles thick. The free-air gravity anomaly, which consists of a large positive maximum flanked by minima, averages very close to zero, indicating that this major crustal feature is regionally compensated, although locally each of its components shows a large departure from equilibrium. Remanent magnetization is a primary factor in the interpretation of the magnetic data. Magnetic property studies of Keweenawan mafic rocks in the Lake Superior region show that remanent magnetization may be five times the magnetization induced by the

  9. High-resolution aeromagnetic mapping of volcanic terrain, Yellowstone National Park

    USGS Publications Warehouse

    Finn, C.A.; Morgan, L.A.

    2002-01-01

    High-resolution aeromagnetic data acquired over Yellowstone National Park (YNP) show contrasting patterns reflecting differences in rock composition, types and degree of alteration, and crustal structures that mirror the variable geology of the Yellowstone Plateau. The older, Eocene, Absaroka Volcanic Supergroup, a series of mostly altered, andesitic volcanic and volcaniclastic rocks partially exposed in mountains on the eastern margin of YNP, produces high-amplitude, positive magnetic anomalies, strongly contrasting with the less magnetic, younger, latest Cenozoic, Yellowstone Plateau Group, primarily a series of fresh and variably altered rhyolitic rocks covering most of YNP. The Yellowstone caldera is the centerpiece of the Yellowstone Plateau; part of its boundary can be identified on the aeromagnetic map as a series of discontinuous, negative magnetic anomalies that reflect faults or zones along which extensive hydrothermal alteration is localized. The large-volume rhyolitic ignimbrite deposits of the 0.63-Ma Lava Creek Tuff and the 2.1-Ma Huckleberry Ridge Tuff, which are prominent lithologies peripheral to the Yellowstone caldera, produce insignificant magnetic signatures. A zone of moderate amplitude positive anomalies coincides with the mapped extent of several post-caldera rhyolitic lavas. Linear magnetic anomalies reflect the rectilinear fault systems characteristic of resurgent domes in the center of the caldera. Peripheral to the caldera, the high-resolution aeromagnetic map clearly delineates flow unit boundaries of pre- and post-caldera basalt flows, which occur stratigraphically below the post-caldera rhyolitic lavas and are not exposed extensively at the surface. All of the hot spring and geyser basins, such as Norris, Upper and Lower Geyser Basins, West Thumb, and Gibbon, are associated with negative magnetic anomalies, reflecting hydrothermal alteration that has destroyed the magnetic susceptibility of minerals in the volcanic rocks. Within

  10. Temperature and heat transfer solutions for aeromagnetic dusty-gas flow

    SciTech Connect

    Chamkha, A.J. )

    1993-09-01

    Based on temperature and heat transfer solutions derived by Chamkha (1992) for aeromagnetic dusty-gas flows (such as are occurring in many industrial processes), this paper investigates the effect of a transverse magnetic field on the temperature profile, and the wall heat transfer for flow of a dusty gas past an infinite porous flat plate. The fluid phase is assumed to be incompressible and electrically conducting, and the particle phase is assumed to be incompressible and electrically nonconducing; it is also assumed that there is no radiative heat transfer from one particle to another and that the particles do not interact with each other. 6 refs.

  11. Detailed interpretation of aeromagnetic data from the Patagonia Mountains area, southeastern Arizona

    USGS Publications Warehouse

    Bultman, Mark W.

    2015-01-01

    Euler deconvolution depth estimates derived from aeromagnetic data with a structural index of 0 show that mapped faults on the northern margin of the Patagonia Mountains generally agree with the depth estimates in the new geologic model. The deconvolution depth estimates also show that the concealed Patagonia Fault southwest of the Patagonia Mountains is more complex than recent geologic mapping represents. Additionally, Euler deconvolution depth estimates with a structural index of 2 locate many potential intrusive bodies that might be associated with known and unknown mineralization.

  12. High-resolution aeromagnetic mapping of volcanic terrain, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Finn, Carol A.; Morgan, Lisa A.

    2002-06-01

    High-resolution aeromagnetic data acquired over Yellowstone National Park (YNP) show contrasting patterns reflecting differences in rock composition, types and degree of alteration, and crustal structures that mirror the variable geology of the Yellowstone Plateau. The older, Eocene, Absaroka Volcanic Supergroup, a series of mostly altered, andesitic volcanic and volcaniclastic rocks partially exposed in mountains on the eastern margin of YNP, produces high-amplitude, positive magnetic anomalies, strongly contrasting with the less magnetic, younger, latest Cenozoic, Yellowstone Plateau Group, primarily a series of fresh and variably altered rhyolitic rocks covering most of YNP. The Yellowstone caldera is the centerpiece of the Yellowstone Plateau; part of its boundary can be identified on the aeromagnetic map as a series of discontinuous, negative magnetic anomalies that reflect faults or zones along which extensive hydrothermal alteration is localized. The large-volume rhyolitic ignimbrite deposits of the 0.63-Ma Lava Creek Tuff and the 2.1-Ma Huckleberry Ridge Tuff, which are prominent lithologies peripheral to the Yellowstone caldera, produce insignificant magnetic signatures. A zone of moderate amplitude positive anomalies coincides with the mapped extent of several post-caldera rhyolitic lavas. Linear magnetic anomalies reflect the rectilinear fault systems characteristic of resurgent domes in the center of the caldera. Peripheral to the caldera, the high-resolution aeromagnetic map clearly delineates flow unit boundaries of pre- and post-caldera basalt flows, which occur stratigraphically below the post-caldera rhyolitic lavas and are not exposed extensively at the surface. All of the hot spring and geyser basins, such as Norris, Upper and Lower Geyser Basins, West Thumb, and Gibbon, are associated with negative magnetic anomalies, reflecting hydrothermal alteration that has destroyed the magnetic susceptibility of minerals in the volcanic rocks. Within

  13. Magnetic character of a large continental transform: an aeromagnetic survey of the Dead Sea Fault

    USGS Publications Warehouse

    ten Brink, Uri S.; Rybakov, Michael; Al-Zoubi, Abdallah S.; Rotstein, Yair

    2007-01-01

    New high-resolution airborne magnetic (HRAM) data along a 120-km-long section of the Dead Sea Transform in southern Jordan and Israel shed light on the shallow structure of the fault zone and on the kinematics of the plate boundary. Despite infrequent seismic activity and only intermittent surface exposure, the fault is delineated clearly on a map of the first vertical derivative of the magnetic intensity, indicating that the source of the magnetic anomaly is shallow. The fault is manifested by a 10–20 nT negative anomaly in areas where the fault cuts through magnetic basement and by a

  14. Integrated analysis of high resolution aeromagnetic and satellite imagery data for hydrocarbon exploration in frontier and mature basins

    SciTech Connect

    Berger, Z.; Nash, C.; Ellis, C.; Witham, B.

    1996-08-01

    Recent improvement in the collection and processing of high resolution aeromagnetic data provides, for the first time, information on the spatial distribution of geological structures in the sedimentary section. The magnetic data, which is presented with a series of color images, can be easily merged and correlated with satellite imagery data, air and space home radar and conventional aerial photography. The integration of these two different reconnaissance tools provides excellent means for structural mapping and early evaluation of hydrocarbon plays in both frontier and mature areas. A series of examples supported by both surface and subsurface controls are used to illustrate the exploration application of these two different data sets. In the frontier fold and thrust belts regions of the North Slope Alaska, the Andes of South America, and the Canadian Foothills, high resolution magnetic images and side-looking air and space borne radar data are effectively used to improve the interpretation of geological structures above the detachment levels. This data was also used to identify the presence of basement involved reactivated structures and related migration pathways. In less deformed and more mature areas, such as the Central Basin Platform of West Texas and the Peace River Arch of the Western Canada Basin, the integration of high resolution magnetic images and Landsat TM data leads to the recognition of new faults and fracture systems and related hydrocarbon plays. The availability of high resolution magnetic surveys and new space borne radar systems such as ERS-1, JERS-1 and RADARSAT should play a significant role in exploration of the heavily vegetated fold belt regions of the tropics as well as the vast plains and plateaus of the South American continent.

  15. The tectonic evolution of the Transbrasiliano Lineament in northern Paraná Basin, Brazil, as inferred from aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Curto, Julia B.; Vidotti, Roberta M.; Fuck, Reinhardt A.; Blakely, Richard J.; Alvarenga, Carlos J. S.; Dantas, Elton L.

    2014-03-01

    Data from six airborne magnetic surveys were compiled and analyzed to develop a structural interpretation for the Transbrasiliano Lineament in northern Paraná Basin, Brazil. Magnetic lineaments, interpreted to reflect geologic contacts and structures at different depths, were illuminated using the matched-filter technique applied to aeromagnetic anomalies. Field-based structural measurements generally support our magnetic analysis. We estimated three primary magnetic zones: (i) a zone of deep magnetic sources at 20 km depth, (ii) an intermediate basement zone at 6 km depth, and (iii) a shallow zone of near-surface geological features at 1.5 km depth. The deepest zone exhibits three major NE trending crustal discontinuities related to the Transbrasiliano Lineament, dividing the region into four geotectonic blocks. Anomalies associated with the intermediate zone indicate directional divergence of subsidiary structures away from the main Transbrasiliano Fault, which strikes N30°E. The shallow magnetic zone includes near-surface post-Brasiliano orogenic granites. Our analysis identified NE trending sigmoidal lineaments around these intrusions, indicating intense zones of deformation associated with probable shear structures. At the shallow depth zone, magnetic anomalies caused by Cretaceous alkaline intrusive bodies and basalts of the Serra Geral Formation are enhanced by the matched-filter method. These igneous bodies are related to extensional NW striking lineaments and seismicity aligned along these lineaments suggests that they currently are reactivated. Prior to flexural subsidence of the Paraná Basin, reactivation processes along transcurrent elements of the Transbrasiliano Lineament promoted extensional processes and formed initial Paraná Basin depocenters. Cretaceous and more recent sedimentation also correlate with reactivations of NE striking structures.

  16. Design and "As Flown" Radiation Environments for Materials in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Minow, Joseph; McWilliams, Brett; Altstatt, Richard; Koontz, Steven

    2006-01-01

    A conservative design approach was adopted by the International Space Station Program for specifying total ionizing radiation dose requirements for use in selecting and qualifying materials for construction of the International Space Station. The total ionizing dose design environment included in SSP 30512 Space Station Ionizing Radiation Design Environment is based on trapped proton and electron fluence derived from the solar maximum versions of the AE-8 and AP-8 models, respectively, specified for a circular orbit at 500 km altitude and 51.7 degree inclination. Since launch, the range of altitudes utilized for Space Station operations vary from a minimum of approximately 330 km to a maximum of approximately 405 km with a mean operational altitude less than 400 km. The design environment, therefore, overestimates the radiation environment because the particle flux in the South Atlantic Anomaly is the primary contributor to radiation dose in low Earth orbit and flux within the Anomaly is altitude dependent. In addition, a 2X multiplier is often applied to the design environment to cover effects from the contributions of galactic cosmic rays, solar energetic particle events, geomagnetic storms, and uncertainties in the trapped radiation models which are not explicitly included in the design environment. Application of this environment may give radiation dose overestimates on the order of 1OX to 30X for materials exposed to the space environment, suggesting that materials originally qualified for ten year exposures on orbit may be used for longer periods without replacement. In this paper we evaluate the "as flown" radiation environments derived from historical records of the ISS flight trajectory since launch and compare the results with the SSP 30512 design environment to document the magnitude of the radiation dose overestimate provided by the design environment. "As flown" environments are obtained from application of the AE-8/AP-8 trapped particle models along

  17. As-Flown Shuttle Micro-Meteoroid Orbital Debris (MMOD) Assessment History

    NASA Technical Reports Server (NTRS)

    Hyde, James L.; Christiansen, Eric L.; Lear, Dana M.; Kerr, Justin H.

    2012-01-01

    The final flight of the Space Shuttle program was completed on July 21st of 2011. The reusable nature of the Orbiter vehicles has provided NASA with a unique opportunity to inspect and sample spacecraft surfaces exposed to the MMOD environment in low Earth orbit. This paper will provide details of MMOD damages found on Orbiter surfaces after recent flights, as well as putting these damages in context by providing historical comparisons of recent damage to previous flights. The Bumper threat assessment computer code is used by NASA to determine spacecraft MMOD penetration risk. The tool was used before each mission to estimate pre-flight MMOD risk for the Shuttle Program Office using planned vehicles attitudes and exposure times. This paper summarizes the efforts of the authors to assess the expected number MMOD impacts of selected particles sizes of 52 shuttle missions ranging from STS-50 (1992) through STS-133 (2011) using as-flown attitude data. The missions encompass the Shuttle/Mir precursors to the International Space Station (ISS) as well as the ISS assembly flights. The paper includes a comparison of observed MMOD impact damage to the predicted number of impacts from Bumper code assessments. This data can be used to validate engineering models of the orbital debris and micrometeoroid environment, such NASA s ORDEM debris model and MEM meteoroid model.

  18. Results from testing and analysis of solar cells flown on LDEF

    NASA Technical Reports Server (NTRS)

    Dursch, Harry

    1992-01-01

    A brief discussion of the solar cell experiments flown on the Long Duration Exposure Facility (LDEF) is provided. The information presented is a collation of results published by the various experimenters. This process of collation and documentation is an ongoing Systems Special Investigation Group (SIG) effort. There are four LEO environments, operating individually and/or synergistically, that cause performance loss in solar cells: meteoroid and space debris, atomic oxygen, ultraviolet radiation, and charged particle radiation. In addition, the effects of contamination caused by outgassing of materials used on the specific spacecraft play a role in decreasing the light being transmitted through the coverglass and adhesive to the solar cell. From the results presented on the solar cells aboard LDEF, the most extensive degradation of the solar cells came from impacts and the resulting cratering. The extent of the damage to the solar cells was largely dependent upon the size and energy of the meteoroids or space debris. The other cause of degradation was reduced light reaching the solar cell. This was caused by contamination, UV degradation of coverglass adhesive, and/or atomic oxygen/UV degradation of antireflection coatings.

  19. Cyclic AMP-receptor proteins in heart muscle of rats flown on Cosmos 1887

    NASA Technical Reports Server (NTRS)

    Mednieks, Maija I.; Popova, Irina A.; Grindeland, Richard E.

    1991-01-01

    The cellular compartmentalization of the cyclic AMP-receptor proteins in heart ventricular tissue obtained from rats flown on the Cosmos 1887 is determined. Photoaffinity labeling of soluble and particular cell fractions with a (32P)-8-azido analog of cyclic AMP is followed by electrophoretic separation of the proteins and by autoradiographic identification of the labeled isoforms of cAPK R subunits. It is shown that RII in the particulate subcellular fraction was significantly decreased in heart cells from rats in the flight group when compared to controls. Protein banding patterns in both the cytoplasmic fraction and in a fraction enriched in chromatin-bound proteins exhibited some variability in tissues of individual animals, but showed no changes that could be directly attributed to flight conditions. No significant change was apparent in the distribution of RI or RII cyclic AMP binding in the soluble fractions. It is inferred that the cardiac cell integrity or its protein content is not compromised under flight conditions.

  20. Pituitary oxytocin and vasopressin content of rats flown on Cosmos 2044

    NASA Technical Reports Server (NTRS)

    Keil, L.; Evans, J.; Grindeland, R.; Krasnov, I.

    1992-01-01

    Preliminary studies in rats (COSMOS 1887) suggested that levels of posterior pituitary hormones were reduced by exposure to spaceflight. To confirm these preliminary findings, pituitary tissue from rats flown for 14 days on Cosmos 2044 is obtained. Posterior pituitary content of oxytocin (OT) and vasopressin (VP) were measured in these tissues as well as those from ground-based controls. The synchronous control group had feeding and lighting schedules synchronized to those in the spacecraft and were maintained in flight-type cages. Another group was housed in vivarium cages; a third group was tail suspended (T), a method used to simulate microgravity. Flight rats showed an average reduction of 27 in pituitary OT and VP compared with the three control groups. When hormone content was expressed in terms of pituitary protein (microg hormone/mg protein), the average decrease in OT and VP for the flight animals ranged from 20 to 33 percent compared with the various control groups. Reduced levels of pituitary OT and VP were similar to preliminary measurements from the Cosmos 1887 mission and appear to result from exposure to spaceflight. These data suggest that changes in the rate of hormone secretion or synthesis may have occurred during exposure to microgravity.

  1. Pituitary oxytocin and vasopressin content of rats flown on COSMOS 2044.

    PubMed

    Keil, L; Evans, J; Grindeland, R; Krasnov, I

    1992-08-01

    Preliminary studies in rats (COSMOS 1887) suggested that levels of posterior pituitary hormones were reduced by exposure to spaceflight. To confirm these preliminary findings, we obtained pituitary tissue from rats flown for 14 days on COSMOS 2044. Posterior pituitary content of oxytocin (OT) and vasopressin (VP) were measured in these tissues as well as those from ground-based controls. The synchronous control group had feeding and lighting schedules synchronized to those in the spacecraft and were maintained in flight-type cages. Another group was housed in vivarium cages; a third group was tail suspended (T), a method used to stimulate microgravity. Flight rats showed an average reduction of 27% (P less than 0.05) in pituitary OT and VP compared with the three control groups. When hormone content was expressed in terms of pituitary protein (micrograms hormone/mg protein), the average decrease in OT and VP for the flight animals ranged from 20 to 33% (P less than 0.05) compared with the various control groups. Reduced levels of pituitary OT and VP were similar to preliminary measurements from the COSMOS 1887 mission and appear to result from exposure to spaceflight. These data suggest that changes in the rate of hormone secretion or synthesis may have occurred during exposure to microgravity.

  2. Molecular Substrate Alteration by Solar Wind Radiation Documented on Flown Genesis Mission Array Materials

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Stansbery, Eileen K.

    2006-01-01

    The Genesis spacecraft sampling arrays were exposed to various regimes of solar wind during flight that included: 313.01 days of high-speed wind from coronal holes, 335.19 days of low-speed inter-stream wind, 191.79 days of coronal mass ejections, and 852.83 days of bulk solar wind at Lagrange 1 orbit. Ellipsometry measurements taken at NASA s Johnson Space Center show that all nine flown array materials from the four Genesis regimes have been altered by solar wind exposure during flight. These measurements show significant changes in the optical constant for all nine ultra-pure materials that flew on Genesis when compared with their non-flight material standard. This change in the optical constant (n and k) of the material suggests that the molecular structure of the all nine ultra-pure materials have been altered by solar radiation. In addition, 50 samples of float-zone and czochralski silicon bulk array ellipsometry results were modeled with an effective medium approximation layer (EMA substrate layer) revealing a solar radiation molecular damage zone depth below the SiO2 native oxide layer ranging from 392 to 613 . This bulk solar wind radiation penetration depth is comparable to the depth of solar wind implantation depth of Mg measured by SIMS and SARISA.

  3. Structure of the Tucson Basin, Arizona from gravity and aeromagnetic data

    USGS Publications Warehouse

    Rystrom, Victoria Louise

    2003-01-01

    Interpretation of gravity and high-resolution aeromagnetic data reveal the three-dimensional geometry of the Tuscson Basin, Arizona and the lithology of its basement. Limited drill hole and seismic data indicate that the maximum depth to the crystalline basement is approximately 3600 meters and that the sedimentary sequences in the upper ~2000 m of the basin were deposited during the most recent extensional episode that commenced about 13 Ma. The negative density contrasts between these upper Neogene and Quaternary sedimentary sequences and the adjacent country rock produce a Bouguer residual gravity low, whose steep gradients clearly define the lateral extent of the upper ~2000m of the basin. The aeromagnetic maps show large positive anomalies associated with deeply buried, late Cretaceous-early Tertiary and mid-Tertiary igneous rocks at and below the surface of the basin. These magnetic anomalies provide insight into the older (>13 Ma) and deeper structures of the basin. Simultaneous 2.5-dimensional modeling of both gravity and magnetic anomalies constrained by geologic and seismic data delineates the thickness of the basin and the dips of the buried faults that bound the basin. This geologic-based forward modeling approach to using geophysical data is shown to result in more information about the geologic and tectonic history of the basin as well as more accurate depth to basement determinations than using generalized geophysical inversion techniques.

  4. An integration of aeromagnetic and electrical resistivity methods in dam site investigation

    SciTech Connect

    Aina, A.; Olorunfemi, M.O.; Ojo, J.S.

    1996-03-01

    Aeromagnetic map and electrical resistivity sounding data obtained along eight traverses were examined at two sites across the Katsina-Ala River. The principal goals of this exercise were to define depths to the bedrock, bedrock relief, geologic structures, define the nature of the superficial deposit, and select probable minor and major axes for hydroelectric power dams. The aeromagnetic map shows that the basement rocks trend roughly northeast-southwest, which correlates with the strike of foliation measurements made on rock outcrops along the river channel. A network of cross cutting lineaments, suspected to be faults/fractures that trend approximately northeast/southwest and northwest/southeast, was also delineated from the magnetic map. The depths to the bedrock estimated from resistivity depth sounding data at site 1 generally vary from 1--53.1 m. Depths to the bedrock estimated at site 2 range from 1.9--19.5 m. The superficial deposit varies from clay to sandy clay, to clayey sand (with boulders in places), and to sand and laterite. The bedrock relief is relatively flat and gently undulates along most of the traverses, with an overall dip towards the river channel. Traverses E-F or I-J at site 1 and K-L at site 2 are probable dame axes. These traverses are characterized by relatively thin overburden thicknesses and rock heads dipping toward the river channel, thereby reducing the likelihood of water seepages from the flanks of the proposed dam axes.

  5. Structure, composition and thermal state of the crust in Brazil. [geomagnetic survey

    NASA Technical Reports Server (NTRS)

    Pacca, I. I. G. (Principal Investigator); Shukowsky, W.

    1981-01-01

    Efforts in support of a geomagnetic survey of the Brazilian area are described. Software to convert MAGSAT data tapes to the Burroughs/B-6700 binary format was developed and tested. A preliminary analysis of the first total intensity anomaly map was performed and methodologies for more intensive analysis were defined. The sources for correlative geological, aeromagnetic, and gravimetric data are described.

  6. Biological and metabolic response in STS-135 space-flown mouse skin.

    PubMed

    Mao, X W; Pecaut, M J; Stodieck, L S; Ferguson, V L; Bateman, T A; Bouxsein, M L; Gridley, D S

    2014-08-01

    There is evidence that space flight condition-induced biological damage is associated with increased oxidative stress and extracellular matrix (ECM) remodeling. To explore possible mechanisms, changes in gene expression profiles implicated in oxidative stress and in ECM remodeling in mouse skin were examined after space flight. The metabolic effects of space flight in skin tissues were also characterized. Space Shuttle Atlantis (STS-135) was launched at the Kennedy Space Center on a 13-day mission. Female C57BL/6 mice were flown in the STS-135 using animal enclosure modules (AEMs). Within 3-5 h after landing, the mice were euthanized and skin samples were harvested for gene array analysis and metabolic biochemical assays. Many genes responsible for regulating production and metabolism of reactive oxygen species (ROS) were significantly (p < 0.05) altered in the flight group, with fold changes >1.5 compared to AEM control. For ECM profile, several genes encoding matrix and metalloproteinases involved in ECM remodeling were significantly up-/down-regulated following space flight. To characterize the metabolic effects of space flight, global biochemical profiles were evaluated. Of 332 named biochemicals, 19 differed significantly (p < 0.05) between space flight skin samples and AEM ground controls, with 12 up-regulated and 7 down-regulated including altered amino acid, carbohydrate metabolism, cell signaling, and transmethylation pathways. Collectively, the data demonstrated that space flight condition leads to a shift in biological and metabolic homeostasis as the consequence of increased regulation in cellular antioxidants, ROS production, and tissue remodeling. This indicates that astronauts may be at increased risk for pathophysiologic damage or carcinogenesis in cutaneous tissue.

  7. Atomic Oxygen and Space Environment Effects on Aerospace Materials Flown with EOIM-3 Experiment

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.; Clatterbuck, Carroll H.; Ayres-Treusdell, Mary; Park, Gloria; Kolos, Diane

    1996-01-01

    Polymer materials samples mounted on a passive carrier tray were flown aboard the STS-46 Atlantis shuttle as complement to the EOIM-3 (Evaluation of Oxygen Interaction with Materials) experiment to evaluate the effects of atomic oxygen on the materials and to measure the gaseous shuttle bay environment. The morphological changes of the samples produced by the atomic oxygen fluence of 2.07 x 10(exp 20) atoms/cm(exp 2) are being reported. The changes have been verified using Electron Spectroscopy for Chemical Analysis (ESCA), gravimetric measurement, microscopic observations and thermo-optical measurements. The samples, including Kapton, Delrin, epoxies, Beta Cloth, Chemglaze Z306, silver Teflon, silicone coatings, 3M tape and Uralane and Ultem, PEEK, Victrex (PES), Polyethersulfone and Polymethylpentene thermoplastic, have been characterized by their oxygen reaction efficiency on the basis of their erosion losses and the oxygen fluence. Those efficiencies have been compared to results from other experiments, when available. The efficiencies of the samples are all in the range of E-24 g/atom. The results indicate that the reaction efficiencies of the reported materials can be grouped in about three ranges of values. The least affected materials which have efficiencies varying from 1 to 10(exp 25) g/atom, include silicones, epoxies, Uralane and Teflon. A second group with efficiency from 10 to 45(exp 25) g/atom includes additional silicone coatings, the Chemglaze Z306 paint and Kapton. The third range from 50 to 75(exp 25) includes organic compound such as Pentene, Peek, Ultem, Sulfone and a 3M tape. A Delrin sample had the highest reaction efficiency of 179(exp 25) g/atom. Two samples, the aluminum Beta cloth X389-7 and the epoxy fiberglass G-11 nonflame retardant, showed a slight mass increase.

  8. Evaluation of Space Power Materials Flown on the Passive Optical Sample Assembly

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; deGroh, Kim K.; Skowronski, Timothy J.; McCollum, Tim; Pippin, Gary; Bungay, Corey

    1999-01-01

    Evaluating the performance of materials on the exterior of spacecraft is of continuing interest, particularly in anticipation of those applications that will require a long duration in low Earth orbit. The Passive Optical Sample Assembly (POSA) experiment flown on the exterior of Mir as a risk mitigation experiment for the International Space Station was designed to better understand the interaction of materials with the low Earth orbit environment and to better understand the potential contamination threats that may be present in the vicinity of spacecraft. Deterioration in the optical performance of candidate space power materials due to the low Earth orbit environment, the contamination environment, or both, must be evaluated in order to propose measures to mitigate such deterioration. The thirty two samples of space power materials studied here include solar array blanket materials such as polyimide Kapton H and SiO(x) coated polyimide Kapton H, front surface aluminized sapphire, solar dynamic concentrator materials such as silver on spin coated polyimide and aluminum on spin coated polyimide, CV 1144 silicone, and the thermal control paint Z-93-P. The physical and optical properties that were evaluated prior to and after the POSA flight include mass, total, diffuse, and specular reflectance, solar absorptance, and infrared emittance. Additional post flight evaluation included scanning electron microscopy to observe surface features caused by the low Earth orbit environment and the contamination environment, and variable angle spectroscopic ellipsometry to identify contaminant type and thickness. This paper summarizes the results of pre- and post-flight measurements, identifies the mechanisms responsible for optical properties deterioration, and suggests improvements for the durability of materials in future missions.

  9. Cyclic AMP-receptor proteins in heart muscle of rats flown on Cosmos 1887.

    PubMed

    Mednieks, M I; Popova, I A; Grindeland, R E

    1991-10-01

    A frequent cellular response to organismal stress is the increase in ligand binding by beta-adrenergic receptors. The extracellular signal is amplified by intracellular increases in cyclic AMP and the ensuing activation of cyclic AMP-dependent protein kinase (cAPK). The molecular mechanisms involve the binding of cyclic AMP to regulatory (R) subunits of cAPK, thus freeing the catalytic subunit for protein phosphorylation. This study was carried out to determine the cellular compartmentalization of the cyclic AMP-receptor proteins in heart ventricular tissue obtained from rats flown on the Cosmos 1887 mission. Photoaffinity labeling of soluble and particulate cell fractions with an [32P]-8-azido analog of cyclic AMP was followed by electrophoretic separation of the proteins and by autoradiographic identification of the labeled isoforms of cAPK R subunits. The results showed that RII in the particulate subcellular fraction was significantly decreased in heart cells from rats in the flight group when compared to controls. Protein banding patterns in both the cytoplasmic fraction and in a fraction enriched in chromatin-bound proteins showed some variability in tissues of individual animals, but exhibited no changes that could be directly attributed to flight conditions. No significant change was apparent in the distribution of RI or RII cyclic AMP binding in the soluble fractions. These findings indicate that the cardiac cell integrity or its protein content is not compromised under flight conditions. There is, however, what appears to be an adaptive molecular response which can be detected using microanalytical methods, indicating that a major hormone regulated mechanism may be affected during some phase of travel in space.

  10. Germination, growth rates, and electron microscope analysis of tomato seeds flown on the LDEF

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.; Bridgers, Kevin; Brown, Cecelia Wright

    1995-01-01

    The tomato seeds were flown in orbit aboard the Long Duration Exposure Facility (LDEF) for nearly six years. During this time, the tomato seeds received an abundant exposure to cosmic radiation and solar wind. Upon the return of the LDEF to earth, the seeds were distributed throughout the United States and 30 foreign countries for analysis. The purpose of the experiment was to determine the long term effect of cosmic rays on living tissue. Our university analysis included germination and growth rates as well as Scanning Electron Microscopy and X-ray analysis of the control as well as Space-exposed tomato seeds. In analyzing the seeds under the Electron Microscope, usual observations were performed on the nutritional and epidermis layer of the seed. These layers appeared to be more porous in the Space-exposed seeds than on the Earth-based control seeds. This unusual characteristic may explain the increases in the space seeds growth pattern. (Several test results show that the Space-exposed seeds germinate sooner than the Earth-Based seeds. Also, the Space-exposed seeds grew at a faster rate). The porous nutritional region may allow the seeds to receive necessary nutrients and liquids more readily, thus enabling the plant to grow at a faster rate. Roots, leaves and stems were cut into small sections and mounted. After sputter coating the specimens with Argon/Gold Palladium Plasma, they were ready to be viewed under the Electron Microscope. Many micrographs were taken. The X-ray analysis displayed possible identifications of calcium, potassium, chlorine, copper, aluminum, silicon, phosphate, carbon, and sometimes sulfur and iron. The highest concentrations were shown in potassium and calcium. The Space-exposed specimens displayed a high concentration of copper and calcium in the two specimens. There was a significantly high concentration of copper in the Earth-based specimens, whereas there was no copper in the Space-exposed specimens.

  11. Biological and metabolic response in STS-135 space-flown mouse skin.

    PubMed

    Mao, X W; Pecaut, M J; Stodieck, L S; Ferguson, V L; Bateman, T A; Bouxsein, M L; Gridley, D S

    2014-08-01

    There is evidence that space flight condition-induced biological damage is associated with increased oxidative stress and extracellular matrix (ECM) remodeling. To explore possible mechanisms, changes in gene expression profiles implicated in oxidative stress and in ECM remodeling in mouse skin were examined after space flight. The metabolic effects of space flight in skin tissues were also characterized. Space Shuttle Atlantis (STS-135) was launched at the Kennedy Space Center on a 13-day mission. Female C57BL/6 mice were flown in the STS-135 using animal enclosure modules (AEMs). Within 3-5 h after landing, the mice were euthanized and skin samples were harvested for gene array analysis and metabolic biochemical assays. Many genes responsible for regulating production and metabolism of reactive oxygen species (ROS) were significantly (p < 0.05) altered in the flight group, with fold changes >1.5 compared to AEM control. For ECM profile, several genes encoding matrix and metalloproteinases involved in ECM remodeling were significantly up-/down-regulated following space flight. To characterize the metabolic effects of space flight, global biochemical profiles were evaluated. Of 332 named biochemicals, 19 differed significantly (p < 0.05) between space flight skin samples and AEM ground controls, with 12 up-regulated and 7 down-regulated including altered amino acid, carbohydrate metabolism, cell signaling, and transmethylation pathways. Collectively, the data demonstrated that space flight condition leads to a shift in biological and metabolic homeostasis as the consequence of increased regulation in cellular antioxidants, ROS production, and tissue remodeling. This indicates that astronauts may be at increased risk for pathophysiologic damage or carcinogenesis in cutaneous tissue. PMID:24796731

  12. Germination, growth rates, and electron microscope analysis of tomato seeds flown on the LDEF

    SciTech Connect

    Hammond, E.C. Jr.; Bridgers, K.; Brown, C.W.

    1995-02-01

    The tomato seeds were flown in orbit aboard the Long Duration Exposure Facility (LDEF) for nearly six years. During this time, the tomato seeds received an abundant exposure to cosmic radiation and solar wind. Upon the return of the LDEF to earth, the seeds were distributed throughout the United States and 30 foreign countries for analysis. The purpose of the experiment was to determine the long term effect of cosmic rays on living tissue. Our university analysis included germination and growth rates as well as Scanning Electron Microscopy and X-ray analysis of the control as well as Space-exposed tomato seeds. In analyzing the seeds under the Electron Microscope, usual observations were performed on the nutritional and epidermis layer of the seed. These layers appeared to be more porous in the Space-exposed seeds than on the Earth-based control seeds. This unusual characteristic may explain the increases in the space seeds growth pattern. (Several test results show that the Space-exposed seeds germinate sooner than the Earth-Based seeds. Also, the Space-exposed seeds grew at a faster rate). The porous nutritional region may allow the seeds to receive necessary nutrients and liquids more readily, thus enabling the plant to grow at a faster rate. Roots, leaves and stems were cut into small sections and mounted. After sputter coating the specimens with Argon/Gold Palladium Plasma, they were ready to be viewed under the Electron Microscope. Many micrographs were taken. The X-ray analysis displayed possible identifications of calcium, potassium, chlorine, copper, aluminum, silicon, phosphate, carbon, and sometimes sulfur and iron. The highest concentrations were shown in potassium and calcium. The Space-exposed specimens displayed a high concentration of copper and calcium in the two specimens. There was a significantly high concentration of copper in the Earth-based specimens, whereas there was no copper in the Space-exposed specimens.

  13. Cyclic AMP-receptor proteins in heart muscle of rats flown on Cosmos 1887.

    PubMed

    Mednieks, M I; Popova, I A; Grindeland, R E

    1991-10-01

    A frequent cellular response to organismal stress is the increase in ligand binding by beta-adrenergic receptors. The extracellular signal is amplified by intracellular increases in cyclic AMP and the ensuing activation of cyclic AMP-dependent protein kinase (cAPK). The molecular mechanisms involve the binding of cyclic AMP to regulatory (R) subunits of cAPK, thus freeing the catalytic subunit for protein phosphorylation. This study was carried out to determine the cellular compartmentalization of the cyclic AMP-receptor proteins in heart ventricular tissue obtained from rats flown on the Cosmos 1887 mission. Photoaffinity labeling of soluble and particulate cell fractions with an [32P]-8-azido analog of cyclic AMP was followed by electrophoretic separation of the proteins and by autoradiographic identification of the labeled isoforms of cAPK R subunits. The results showed that RII in the particulate subcellular fraction was significantly decreased in heart cells from rats in the flight group when compared to controls. Protein banding patterns in both the cytoplasmic fraction and in a fraction enriched in chromatin-bound proteins showed some variability in tissues of individual animals, but exhibited no changes that could be directly attributed to flight conditions. No significant change was apparent in the distribution of RI or RII cyclic AMP binding in the soluble fractions. These findings indicate that the cardiac cell integrity or its protein content is not compromised under flight conditions. There is, however, what appears to be an adaptive molecular response which can be detected using microanalytical methods, indicating that a major hormone regulated mechanism may be affected during some phase of travel in space. PMID:1662483

  14. Experimental low-altitude aeromagnetic reconnaissance for petroleum in Arctic-National Wildlife Refuge, Alaska, using horizontal gradients: a progress report

    SciTech Connect

    Donovan, T.J.; Hendricks, J.D.; Roberts, A.A.; Eliason, P.T.

    1983-03-01

    Variations in the earth's magnetic field arising from areally restricted increased amounts of shallow-buried magnetite over hydrocarbon deposits have been mapped in the Arctic National Wildlife Refuge and elsewhere is northern Alaska. The anomalies have been delineated with a low-flying (90 m; 295 ft) magnetic horizontal gradiometer mounted on a fixed-wing airplane. Limited data from stable carbon isotope and remanent magnetism measurements of rock cores from the Cape Simpson region strongly suggest that the magnetic anomalies result from the chemical reduction of iron oxides in the presence of seeping hydrocarbons. Magnetometers extended from each wingtip and in a tail stinger permit calculation of the resultant horizontal gradient vector relative to the flight path. This calculation provides data for the unmeasured area between adjacent flight lines spaced at 1.5 km (.9 mi), thereby allowing generation of accurate computer-enhanced images or maps. Problems related to diurnal variations and solar storms at high magnetic latitude are largely overcome because changes in the total magnetic field do not significantly affect the magnetic gradient. Analysis of an experimental survey, covering 4418 line km (2745 line mi), suggests that the Marsh Creek anticline in the Arctic National Wildlife Refuge is prospective for oil and/or gas. Additional magnetic anomalies were also identified. Although the effect of permafrost on epigenetic processes has not been investigated, the data suggest that special purpose aeromagnetic surveying may be a useful and relatively inexpensive way to explore for oil and gas in this hostile environment.

  15. 7 CFR 2.8 - Delegations of authority to agency heads to order that the United States flag be flown at half...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... heads to order that the United States flag be flown at half-staff. Pursuant to section 5 of Proclamation 3044, 3 CFR, 1954-1958 Comp., p. 4, each general officer and agency head is delegated authority to... the United States flag be flown at half-staff. 2.8 Section 2.8 Agriculture Office of the Secretary...

  16. 7 CFR 2.8 - Delegations of authority to agency heads to order that the United States flag be flown at half...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... heads to order that the United States flag be flown at half-staff. Pursuant to section 5 of Proclamation 3044, 3 CFR, 1954-1958 Comp., p. 4, each general officer and agency head is delegated authority to... the United States flag be flown at half-staff. 2.8 Section 2.8 Agriculture Office of the Secretary...

  17. 7 CFR 2.8 - Delegations of authority to agency heads to order that the United States flag be flown at half...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... heads to order that the United States flag be flown at half-staff. Pursuant to section 5 of Proclamation 3044, 3 CFR, 1954-1958 Comp., p. 4, each general officer and agency head is delegated authority to... the United States flag be flown at half-staff. 2.8 Section 2.8 Agriculture Office of the Secretary...

  18. 7 CFR 2.8 - Delegations of authority to agency heads to order that the United States flag be flown at half...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... heads to order that the United States flag be flown at half-staff. Pursuant to section 5 of Proclamation 3044, 3 CFR, 1954-1958 Comp., p. 4, each general officer and agency head is delegated authority to... the United States flag be flown at half-staff. 2.8 Section 2.8 Agriculture Office of the Secretary...

  19. 7 CFR 2.8 - Delegations of authority to agency heads to order that the United States flag be flown at half...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... heads to order that the United States flag be flown at half-staff. Pursuant to section 5 of Proclamation 3044, 3 CFR, 1954-1958 Comp., p. 4, each general officer and agency head is delegated authority to... the United States flag be flown at half-staff. 2.8 Section 2.8 Agriculture Office of the Secretary...

  20. Precambrian crystalline basement map of Idaho-an interpretation of aeromagnetic anomalies

    USGS Publications Warehouse

    Sims, P.K.; Lund, Karen; Anderson, E.

    2005-01-01

    Idaho lies within the northern sector of the U.S. Cordillera astride the boundary between the Proterozoic continent (Laurentia) to the east and the Permian to Jurassic accreted terranes to the west. The continental basement is mostly covered by relatively undeformed Mesoproterozoic metasedimentary rocks and intruded or covered by Phanerozoic igneous rocks; accordingly, knowledge of the basement geology is poorly constrained. Incremental knowledge gained since the pioneering studies by W. Lindgren, C.P. Ross, A.L. Anderson, A. Hietanen, and others during the early- and mid-1900's has greatly advanced our understanding of the general geology of Idaho. However, knowledge of the basement geology remains relatively poor, partly because of the remoteness of much of the region plus the lack of a stimulus to decipher the complex assemblage of high-grade gneisses and migmatite of central Idaho. The availability of an updated aeromagnetic anomaly map of Idaho (North American Magnetic Anomaly Group, 2002) provides a means to determine the regional Precambrian geologic framework of the State. The combined geologic and aeromagnetic data permit identification of previously unrecognized crystalline basement terranes, assigned to Archean and Paleoproterozoic ages, and the delineation of major shear zones, which are expressed in the aeromagnetic data as linear negative anomalies (Finn and Sims, 2004). Limited geochronologic data on exposed crystalline basement aided by isotopic studies of zircon inheritance, particularly Bickford and others (1981) and Mueller and others (1995), provide much of the geologic background for our interpretation of the basement geology. In northwestern United States, inhomogeneities in the basement inherited from Precambrian tectogenesis controlled many large-scale tectonic features that developed during the Phanerozoic. Two basement structures, in particular, provided zones of weakness that were repeatedly rejuvenated: (1) northeast-trending ductile

  1. Germination, growth rates, and electron microscope analysis of tomato seeds flown on the LDEF.

    PubMed

    Hammond, E C; Bridgers, K; Berry, F D

    1996-11-01

    The purpose of the experiment was to determine cosmic rays long-term effects on living tissue. A batch of tomato seeds were flown in orbit aboard the Long Duration Exposure Facility (LDEF) for almost 6 y. During this time, the seeds received an abundant exposure to cosmic radiation. Upon the return of the LDEF to Earth, the seeds were distributed throughout the United States and 30 foreign countries for analysis. Our university analysis included germination and growth rates as well as scanning electron microscopy (SEM) and X-ray analysis of the control as well as space exposed tomato seeds. In analyzing the seeds under the electron microscope, usual observations were performed on the nutritional and epidermis layer of the seed. These layers appeared to be more porous in the space exposed seeds than on Earth-based control seeds. This unusual characteristic may explain the increases in the space seeds growth pattern. (Several test results showed that the space-exposed seeds germinated sooner than Earth-based seeds. Also, the space-exposed seeds grew at a faster rate.) The porous nutritional region may allow the seeds to receive necessary nutrients and liquids more readily, thus enabling the plant to grow at a faster rate. Roots, leaves and stems were cut into small sections and mounted. After sputter coating the specimens with argon/gold palladium plasma, they were viewed under the electron microscope. Many micrographs were taken. The X-ray analysis displayed possible identifications of calcium, potassium, chlorine, copper, aluminum, silicon, phosphate, carbon, and sometimes sulfur and iron. The highest concentrations were shown in potassium and calcium. As a result of the electron interaction and X-ray production within the open seeds, the traditional layers of the space-exposed seed gave peaks of Mg, P and S, while the Earth seed gave an iron peak, which was not detected in the space-exposed seed because of electron beam positioning difference. The space

  2. Space flight effects on Paramecium tetraurelia flown aboard Salyut 6 in the Cytos I and Cytos M experiments.

    PubMed

    Panel, H; Tixador, R; Nefedov, Y u; Gretchko, G; Richoilley, G; Bassler, R; Monrozies, E

    1981-01-01

    Results of the Cytos M experiment and complementary results of the Cytos I experiment flown aboard the Soviet orbital station Salyut 6 are shown. Space flight of Paramecia cultures resulted in a stimulating effect on cell proliferation, in a larger cell volume, in changes in cell dry weight, cell total protein and the electrolyte content of the culture media in which the organisms were grown. The assumption of a possible effect of weightlessness on membrane permeability is discussed.

  3. Environmental design criteria. [analysis of upper atmospheric wind observed by Low-G accelerometer flown on Agena

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1974-01-01

    Wind velocities at 140-200 km altitude were observed by a Low-G Accelerometer Calibration System (LOGACS) flown on an Agena satellite during a geomagnetic storm. An interesting wind reversal observed by the satellite at auroral latitudes is satisfactorily explained by the neutral air motion caused by the E x B drift deduced from the ground-based geomagnetic data recorded at stations near the meridian of the satellite orbit.

  4. Precambrian Basement Structure Map of the Continental United States - An Interpretation of Geologic and Aeromagnetic Data

    USGS Publications Warehouse

    Sims, Paul K.; Saltus, Richard W.; Anderson, Eric D.

    2008-01-01

    The Precambrian basement rocks of the continental United States are largely covered by younger sedimentary and volcanic rocks, and the availability of updated aeromagnetic data (NAMAG, 2002) provides a means to infer major regional basement structures and tie together the scattered, but locally abundant, geologic information. Precambrian basement structures in the continental United States have strongly influenced later Proterozoic and Phanerozoic tectonism within the continent, and there is a growing awareness of the utility of these structures in deciphering major younger tectonic and related episodes. Interest in the role of basement structures in the evolution of continents has been recently stimulated, particularly by publications of the Geological Society of London (Holdsworth and others, 1998; Holdsworth and others, 2001). These publications, as well as others, stress the importance of reactivation of basement structures in guiding the subsequent evolution of continents. Knowledge of basement structures is an important key to understanding the geology of continental interiors.

  5. Structural model of the San Bernardino basin, California, from analysis of gravity, aeromagnetic, and seismicity data

    USGS Publications Warehouse

    Anderson, M.; Matti, J.; Jachens, R.

    2004-01-01

    The San Bernardino basin is an area of Quaternary extension between the San Jacinto and San Andreas Fault zones in southern California. New gravity data are combined with aeromagnetic data to produce two- and three-dimensional models of the basin floor. These models are used to identify specific faults that have normal displacements. In addition, aeromagnetic maps of the basin constrain strike-slip offset on many faults. Relocated seismicity, focal mechanisms, and a seismic reflection profile for the basin area support interpretations of the gravity and magnetic anomalies. The shape of the basin revealed by our interpretations is different from past interpretations, broadening its areal extent while confining the deepest parts to an area along the modern San Jacinto fault, west of the city of San Bernardino. Through these geophysical observations and related geologic information, we propose a model for the development of the basin. The San Jacinto fault-related strike-slip displacements started on fault strands in the basin having a stepping geometry thus forming a pull-apart graben, and finally cut through the graben in a simpler, bending geometry. In this model, the San Bernardino strand of the San Andreas Fault has little influence on the formation of the basin. The deep, central part of the basin resembles classic pull-apart structures and our model describes a high level of detail for this structure that can be compared to other pull-apart structures as well as analog and numerical models in order to better understand timing and kinematics of pull-apart basin formation. Copyright 2004 by the American Geophysical Union.

  6. Los Azufres silicic center (Mexico): inference of caldera structural elements from gravity, aeromagnetic, and geoelectric data

    NASA Astrophysics Data System (ADS)

    Campos-Enriquez, J. O.; Gardun˜o-Monroy, V. H.

    1995-08-01

    Los Azufres geothermal field is located within a silicic volcanic complex in central Mexico. The complex is one of the major silicic centers in the Trans-Mexican Volcanic Belt (TMVB). Pradal and Robin (1985) first suggested the existence of the Los Azufres caldera, and Ferrari et al. (1991) recognized the existence of a collapse structure. According to Pradal and Robin this is a caldera of resurgent type. This geophysical study aims to contribute to the knowledge of the structure of the Los Azufres area. Gravity, aeromagnetic, magnetotelluric (MT) and d.c. vertical electric-resistivity soundings were analyzed. Results show that Los Azufres is a very structurally complex setting with relatively thin crust caused by the extensional tectonics characterizing this central sector of the TMVB. Faults belonging to the E-W to NE-SW (extensional neotectonics) and NW-SE (Basin and Range province) systems are observed to affect the geologic units of Los Azufres. According to our study, the Los Azufres geothermal field is located in a structural high located in the middle of a sub-circular depression delimited to the north-northeast by the Santa Ines Range, and to the southwest by the Mil Cumbres formation. The larger depression consists of two narrow, deep depressions that correspond to La Venta and to the Valley of Juarez. They are separated by the above mentioned structural high. These sub-depressions are believed to be the sites of a maximum caldera collapse, and the structural high is interpreted to be at least in part the caldera's resurgent dome. Geoelectric structure of the caldera derived from d.c. resistivity indicates that the brines of the Los Azufres geothermal system ascend along faults, both bounding and internally disrupting the structural high/resurgent dome. A reasonable correlation is observed between gravity and aeromagnetic data.

  7. Regional and local controls on mineralization and pluton emplacement in the Bondy gneiss complex, Grenville Province, Canada interpreted from aeromagnetic and gravity data

    NASA Astrophysics Data System (ADS)

    Dufréchou, G.; Harris, L. B.; Corriveau, L.; Antonoff, V.

    2015-05-01

    The Bondy gneiss complex in the Grenville Province of Southwest Quebec hosts a mineralized iron oxide- and copper-rich hydrothermal system. The northern part of the complex overlies the lithospheric-scale Mont-Laurier lineament and is cut by the regional Mont-Laurier South shear zone interpreted from Bouguer gravity. A sinistral 6 km wide strike-slip corridor defined by several second-order shears (the Mont-Laurier South shear zone) in the complex was identified from geophysical data, including a new high-resolution airborne magnetic survey, and field observations. The spatial association of a metamorphosed alteration system, several pre- to post-metamorphic mineralized zones and mafic intrusions within the Mont-Laurier South shear zone suggests that (i) underlying basement structures controlled hydrothermal fluid migration during the formation of epithermal-IOCG mineralization and associated alteration system before ca. 1.2 Ga high-grade metamorphism and penetrative ductile deformation in the complex; (ii) post-metamorphic reactivation allowed magma ascent and pluton emplacement in the complex and adjacent supracrustal rocks within dilatational sites; and (iii) brittle-ductile shears that postdate high-grade metamorphism provided channel ways for fluid migration associated with magnetite-related mineralization. Although the complex does not host an economic mineral deposit, the role between structures at different levels and the combination of gravity and aeromagnetics at different scales provides an example of an approach for mineral exploration in similar high grade gneiss terrains.

  8. Basement, Curie isotherm and shallow-crustal structure of the Trans-Mexican Volcanic Belt, from aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Campos-Enriquez, J. O.; Arroyo-Esquivel, M. A.; Urrutia-Fucugauchi, J.

    1990-01-01

    Regional aeromagnetic data from the western part of the Trans-Mexican Volcanic Belt (TMVB) have been analyzed using the spectral method to estimate depths to the magnetic basement and shallower magnetic interfaces. The basal calc-alkaline volcanic products (Miocene-Early Pliocene) of the TMVB become thinner from west to east, whereas the Plio-Quaternary volcanism becomes thinner from east to west. The underlying sedimentary Mesozoic sequence is thicker in the east. A crystalline basement proper is observed from the Guadalajara City area to the east. To the west of Guadalajara, the basement is represented by a granitic substratum which is extensively exposed in the Jalisco block. Preliminary estimates indicate that the Curie point isotherm ranges from 7 to 14 km, which is in agreement with heat flow studies in the area. The crustal structure inferred from the aeromagnetic data and regional geology, is constructed for ten sections which correspond to the geophysical profiles.

  9. Aeromagnetic anomaly patterns reveal buried faults along the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

    USGS Publications Warehouse

    Armadillo, E.; Ferraccioli, F.; Zunino, A.; Bozzo, E.

    2007-01-01

    The Wilkes Subglacial Basin (WSB) is the major morphological feature recognized in the hinterland of the Transantarctic Mountains. The origin of this basin remains contentious and relatively poorly understood due to the lack of extensive geophysical exploration. We present a new aeromagnetic anomaly map over the transition between the Transantarctic Mountains and the WSB for an area adjacent to northern Victoria Land. The aeromagnetic map reveals the existence of subglacial faults along the eastern margin of the WSB. These inferred faults connect previously proposed fault zones over Oates Land with those mapped along the Ross Sea Coast. Specifically, we suggest a link between the Matusevich Frature Zone and the Priestley Fault during the Cenozoic. The new evidence for structural control on the eastern margin of the WSB implies that a purely flexural origin for the basin is unlikely.

  10. Estimation of Precambrian basement topography in Central and Southeastern Wisconsin from 3D modeling of gravity and aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Skalbeck, John D.; Koski, Adrian J.; Peterson, Matthew T.

    2014-07-01

    Increased concerns about groundwater resources in Wisconsin have brought about the need for better understanding of the subsurface geologic structure that leads to developing conceptual hydrogeologic models for numerical simulation of groundwater flow. Models are often based on sparse data from well logs usually located large distances apart and limited in depth. Model assumptions based on limited spatial data typically require simplification that may add uncertainty to the simulation results and the accuracy of a groundwater model. Three dimensional (3D) modeling of gravity and aeromagnetic data provides another tool for the groundwater modeler to better constrain the conceptual model of a hydrogeologic system. The area near the Waukesha Fault in southeastern Wisconsin provides an excellent research opportunity for our proposed approach because of the strong gravity and aeromagnetic anomalies associated with the fault, the apparent complexity in fault geometry, and uncertainty in Precambrian basement depth and structure. Fond du Lac County provides another opportunity to apply this approach because the Precambrian basement topography throughout the area is known to be very undulated and this uneven basement surface controls water well yields and creates zones of stagnant water. The results of the 3D modeling of gravity and aeromagnetic data provide a detailed estimation of the Precambrian basement topography in Fond Du Lac County and southeastern Wisconsin that may be useful in determining ground water flow and quality in this region.

  11. Curie point depth and heat flow from spectral analysis of aeromagnetic data over the northern part of Western Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Saada, Saada Ahmed

    2016-11-01

    The present work aims to estimate the Curie point depth and the surface heat flow for the northern part of the Western Desert using aeromagnetic data. Applying spectral analysis to aeromagnetic anomalies has provided equitable promising geological results, useful for further geothermal or petroleum exploration. The total intensity aeromagnetic map was first reduced to the north magnetic pole to correct the shape and position of different magnetic anomalies over their causative bodies. Secondly, the short wavelengths were removed to enhance the deeper long wavelengths related to the deep sources. Spectral analysis indicates that the area is underlined by an average Curie point depth of about 27 km. This implies an average thermal heat flow (53 mW/m2) lower than the average global heat flow. The investigated area was divided into eighteen blocks, where the average depths to centroid and top of the magnetic source were estimated for each block. The results of this work show a general depth increase of the magnetic boundaries from 24.5 km in the southern area to 33 km at the northern part. The calculated surface heat flow decreases from about 56 to 42 mW/m2 in the same direction. Consequently, this area is characterized by its low geothermal gradient and surface heat flow. This low geothermal gradient indicates that the upper mantle contributes to the magnetic features at the northern offshore parts. This work also recommends by deep drilling for petroleum exploration and production within the Egyptian Mediterranean Sea exploration strip.

  12. Airborne radioactivity survey in the vicinity of Grants, McKinley and Valencia Counties, New Mexico

    USGS Publications Warehouse

    Stead, Frank W.

    1951-01-01

    An airborne radioactivity survey in the vicinity of Grants, New Mexico, was made on May 28. 1951; aeromagnetic measurements were made concurrently with the radioactivity measurements. Several radioactivity anomalies were noted in conjunction with negative magnetic anomalies; this association is unusual and may reflect a genetic relationship between the uranium mineralization and the geologic structure causing the negative magnetic effect. Further investigation of the vicinity of the anomalies near the Haystack area, including ground magnetometer survey, seems warranted.

  13. Results of the joint utilization of laser integrated experiments flown on payload GAS-449 aboard Columbia mission 61-C

    NASA Technical Reports Server (NTRS)

    Muckerheide, M. C.

    1987-01-01

    The high peak power neodymium YAG laser and the HeNe laser aboard GAS-449 have demonstrated the survivability of the devices in the micro-gravity, cosmic radiation, thermal, and shock environment of space. Some pharmaceuticals and other materials flown in both the active and passive status have demonstrated reduction in volume and unusual spectroscopic changes. X-ray detectors have shown cosmic particle hits with accompanying destruction at their interaction points. Some scattering in the plates is in evidence. Some results of both active and passive experiments on board the GAS-449 payload are evaluated.

  14. Changes in developmental capacity of artemia cyst and chromosomal aberrations in lettuce seeds flown aboard Salyut-7 (Biobloc III experiment)

    NASA Astrophysics Data System (ADS)

    Nevzgodina, V.; Kovalev, E. E.; Maximova, E. N.; Gaubin, Y.; Planel, H.; Gasset, G.; Pianezzi, B.; Clegg, J.

    This paper gives the results of investigations performed on the first container (A) of the Biobloc III experiment, flown aboard the orbital station Salyut 7 for 40 days. The space flight resulted in a decreased developmental capacity of Artemia cysts, hit or not hit by the HZE particles. No effect was observed in cysts in bulk. A synergetic effect of microgravity and gamma pre irradiation is described. The germination of in-flight lettuce seeds was decreased. The space flight resulted also in a higher percentage of cells with chromosomal aberrations. Relations between biological response, TEL and location of HZE particles are discussed.

  15. Regulation of eIF2α phosphorylation in hindlimb-unloaded and STS-135 space-flown mice

    NASA Astrophysics Data System (ADS)

    Zhao, Liming; Tanjung, Nancy; Swarnkar, Gaurav; Ledet, Eric; Yokota, Hiroki

    2012-09-01

    Various environmental stresses elevate the phosphorylation level of eukaryotic translation initiation factor 2 alpha (eIF2α) and induce transcriptional activation of a set of stress responsive genes such as activating transcription factors 3 and 6 (ATF3 and ATF6), CCAAT/enhancer-binding protein homologous protein (CHOP), and Xbp1 (X-box binding protein 1). These stress sources include radiation, oxidation, and stress to the endoplasmic reticulum, and it is recently reported that unloading by hindlimb unloading is such a stress source. No studies, however, have examined the phosphorylation level of eIF2α (eIF2α-p) using skeletal samples that have experienced microgravity in space. In this study we addressed a question: Does a mouse tibia flown in space show altered levels of eIF2α-p? To address this question, we obtained STS-135 flown samples that were harvested 4-7 h after landing. The tibia and femur isolated from hindlimb unloaded mice were employed as non-flight controls. The effects of loading were also investigated in non- flight controls. Results indicate that the level of eIF2α-p of the non-flight controls was elevated during hindlimb unloading and reduced after being released from unloading. Second, the eIF2α-p level of space-flown samples was decreased, and mechanical loading to the tibia caused the reduction of the eIF2α-p level. Third, the mRNA levels of ATF3, ATF6, and CHOP were lowered in space-flown samples as well as in the non-flight samples 4-7 h after being released from unloading. Collectively, the results herein indicated that a release from hindlimb unloading and a return to normal weight environment from space provided a suppressive effect to eIF2α-linked stress responses and that a period of 2-4 h is sufficient to induce this suppressive outcome.

  16. Application Of Continuous Wavelet Transform On Aeromagnetic Data To Identify Volcanic Rocks

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Li, Y.; Liu, T.

    2008-12-01

    This paper focuses on the application of continuous wavelet transform on aeromagnetic data, to locate and characterize volcanic rocks. The studied structure is sited in the north centre of the Huanghua depression in the Bohaiwan basin of east China. As channels of magmatism activities, the faults have caused multi-stage magma outpouring and intrusion, forming igneous rocks of different series of strata. As a traditional frequency decomposition method, the discrete wavelet transform is unable to localize frequency variations over time. To handle this problem, the short time Fourier transform method is widely used for the decomposition of non-stationary signals. One problem with this approach is that the fixed width `window function' results in limited resolution. Therefore, the continuous wavelet transform decomposition was used as an alternative approach to overcome this resolution problem. In the continuous wavelet transform, the signal is multiplied with a function similar to a `window function' but the width of the window is not fixed. The time window width is allowed to vary depending upon the frequency that is being considered. As for the magnetic anomalies of igneous rocks, they have different frequencies due to their depths; by analyzing the complex wavelet-based time-frequency characteristics of certain frequencies, we can identify the residual anomalies caused by volcanic rocks in different depths. The theoretical results show that local high frequency spectrum anomalies are the reflection of magnetic sources, and different scales (or different center frequencies) reflect different source depths, with larger scales for deeper sources. Therefore, by analyzing the complex wavelet-based frequency spectrum under different centre frequencies, we can analyze the distribution of magnetic field sources. Then the continuous wavelet transform was applied on the RTP aeromagnetic data of our study area. The data processing results present a detailed description of the

  17. Detection of DNA Damage by Space Radiation in Human Fibroblast Cells Flown on the International Space Station

    NASA Technical Reports Server (NTRS)

    Wu, Honglu; Lu, Tao; Wong, Michael; Beno, Jonathan; Countryman, Stefanie; Stodieck, Louis; Karouia, Fathi; Zhang, Ye

    2015-01-01

    Although charged particles in space have been detected with radiation detectors on board spacecraft since the early discovery of the Van Allen Belt, reports on effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation has been difficult due to the low dose and low dose rate nature of the radiation environment, and the difficulty in separating the radiation effects from microgravity and other space environmental factors. In astronauts, only a small number of changes, such as increased chromosome aberrations in lymphocytes and early onset of cataracts, attributed primarily to the exposure to space radiation. In a recent experiment, human fibroblast cells were flown on the International Space Station (ISS). Cells fixed on Days 3 and 14 after reaching orbit were analyzed for phosphorylation of a histone protein H2AX by immunofluorescent staining of cells, which is a widely used marker for DNA double strand breaks. The 3-dimensional gamma-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed a small fraction of foci that were larger and displayed a track pattern in the flight samples in comparison to the ground control. Human fibroblast cells were also exposed to low dose rate gamma rays, as well as to protons and Fe ions. Comparison of the pattern and distribution of the foci after gamma ray and charged particle exposure to our flight results confirmed that the foci found in the flown cells were indeed induced by space radiation.

  18. New aeromagnetic data reveal large strike-slip (?) faults inthe Northern Willamette Valley, Oregon

    USGS Publications Warehouse

    Blakely, R.J.; Wells, R.E.; Tolan, T.L.; Beeson, M.H.; Trehu, A.M.; Liberty, L.M.

    2000-01-01

    High-resolution aeromagnetic data from the northern Willamette Valley, Oregon, reveal large, northwest-striking faults buried beneath Quaternary basin sediments. Several faults known from geologic mapping are well defined by the data and appear to extend far beyond their mapped surface traces. The Mount Angel fault, the likely source of the Richter magnitude (M1) 5.6 earthquake in 1993, is at least 55 km long and may be connected in the subsurface with the Gales Creek fault 25 km farther northwest. Northeast of the Mount Angel fault, a 60-km-long, northwest-striking anomaly may represent a previously unrecognized dextral-slip fault beneath the towns of Canby and Molalla. Vertical offsets along the Mount Angel fault increase with depth, indicating a long history of movement for the fault. Dominantly northwest- trending, relatively straight faults, consistent stepover geometries, offset magnetic anomalies and earthquake focal mechanisms suggest that these faults collectively accommodate significant dextral slip. The 1993 earthquake may have occured on a left-stepping restraining bend along the Mount Angel-Gales Creek fault zone.

  19. Can we estimate total magnetization directions from aeromagnetic data using Helbig's integrals?

    USGS Publications Warehouse

    Phillips, J.D.

    2005-01-01

    An algorithm that implements Helbig's (1963) integrals for estimating the vector components (mx, my, mz) of tile magnetic dipole moment from the first order moments of the vector magnetic field components (??X, ??Y, ??Z) is tested on real and synthetic data. After a grid of total field aeromagnetic data is converted to vector component grids using Fourier filtering, Helbig's infinite integrals are evaluated as finite integrals in small moving windows using a quadrature algorithm based on the 2-D trapezoidal rule. Prior to integration, best-fit planar surfaces must be removed from the component data within the data windows in order to make the results independent of the coordinate system origin. Two different approaches are described for interpreting the results of the integration. In the "direct" method, results from pairs of different window sizes are compared to identify grid nodes where the angular difference between solutions is small. These solutions provide valid estimates of total magnetization directions for compact sources such as spheres or dipoles, but not for horizontally elongated or 2-D sources. In the "indirect" method, which is more forgiving of source geometry, results of the quadrature analysis are scanned for solutions that are parallel to a specified total magnetization direction.

  20. Nature of basement rocks under the Los Angeles Basin, southern California, as inferred from aeromagnetic data

    SciTech Connect

    Langenheim, V.E.; Jachens, R.C. . Branch of Geophysics)

    1993-04-01

    The Los Angeles (L.A.) Basin, one of the world's richest oil-producing basins, is underlain by at least two basement assemblages. Because the thickness of the basin sediments reaches up to a minimum of 10 km, magnetic data allow a more regional view of the juxtaposition and nature of basement rocks than do available drill-hole data. Aeromagnetic data indicate that a zone of magnetic rocks extends along the coast east of the Newport-Inglewood fault zone from the San Joaquin Hills northwest to the Santa Monica Mountains. The magnetic highs produced by these rocks appear to be a continuation of intense magnetic highs that are present over exposed rocks of the Peninsular Ranges batholith to the southwest. Modeling of a 180 nT magnetic high over the San Joaquin Hills indicates that the tops of two concealed magnetic sources are at about 1.5 km and 4.5 km depth, which places these bodies at or beneath the basement surface. Modeling of magnetic highs over the exposed batholithic rocks to the south reveals a source with similar geometry and magnetic properties. The associated gravity highs of the San Joaquin Hills suggest that the probable lithology of these concealed magnetic bodies is a dense crystalline rock such as gabbro.

  1. Compatibility study of the Magsat data and aeromagnetic data in the eastern Piedmont of US

    NASA Technical Reports Server (NTRS)

    Won, I. J. (Principal Investigator)

    1980-01-01

    Data from a 2 day period recorded by Magsat were used to produce world magnetic maps of the scalar total field and three vector component total fields. Subtracting the reference field of Magsat 6/80, a scalar anomalous field and three vector component anomalous fields were also mapped. After removing 718 bad points from the original data, every fifth point was picked for contouring. While the main geomagnetic field of the Earth is surprisingly well mapped considering the short data period, the anomaly maps suffer from data sparseness. The entire Magsat file collected at altitudes of 500-700 m in nonmountainous terrain and at 900-1,000 m in mountainous terrain was averaged to reduce the total data to 6,500 measurements, yielding a 0.1 deg sampling interval along the flight path. A U.S. aeromagnetic anomaly surface map was produced and the field was upward continued to a 300 km altitude. Differences in anomaly structure between the POGO data and the map produced were attributed to insufficient removal of the reference field. Reprocessing of the data using the GSFC reference field (9/80-2) should remove the low harmonic field and improve the anomalous field structure.

  2. Research on RTP aeromagnetic gradient data and its applicability in different latitudes

    NASA Astrophysics Data System (ADS)

    Li, Lin; Guo, Hua; Wang, Ping; Jia, Wei-Jie

    2016-03-01

    Aeromagnetic gradient data needs to be reduced to the pole so that it can be better applied to geological interpretation through theoretical derivation. In this paper, we conduct research on the morphological characteristics of the total and horizontal gradient modules before and after reduction to the pole and design models at different latitudes, with consistent and inconsistent magnetic field direction and geological body magnetization direction. We discuss how to use the total gradient module and horizontal gradient module in geological interpretation. The reduced-to-the-pole (RTP) method is required for the horizontal gradient module method but not for the total gradient module. Finally, the conclusions derived from the theoretical models are verified through analysis of real data. The position determination of a geological body using the total gradient method, gradient data, or total-field data works better without RTP, ensuring data primitive authenticity. However, the horizontal gradient module should be reduced to the pole to determine the boundary of the geological body. Finally, the theoretical model is verified by actual data analysis. Both the total and horizontal gradient methods can be applied to geological interpretation.

  3. Testing the use of aeromagnetic data for the determination of Curie depth in California

    USGS Publications Warehouse

    Ross, H.E.; Blakely, R.J.; Zoback, M.D.

    2006-01-01

    Using California as a test region, we have examined the feasibility of using Curie-isotherm depths, estimated from magnetic anomalies, as a proxy for lithospheric thermal structure. Our method follows previous studies by dividing a regional aeromagnetic database into overlapping subregions and analyzing the power-density spectrum of each subregion, but we have improved on previous studies in two important ways: We increase subregion dimensions in a stepwise manner until long-wavelength anomalies are appropriately sampled, and each subregion spectrum determined from the magnetic anomalies is manually fit with a theoretical expression that directly yields the depth to the bottom of the magnetic layer. Using this method, we have obtained Curie-isotherm depths for California that show a general inverse correlation with measured heat flow, as expected. The Coast Ranges of California are characterized by high heat flow (80-85 mW/m2) and shallow Curie depths (20-30 km), whereas the Great Valley has low heat flow (less than 50 mW/m2) and deeper Curie depths (30-45 km). ?? 2006 Society of Exploration Geophysicists.

  4. Curie temperature isotherm analysis and tectonic implications of aeromagnetic data from Nevada

    USGS Publications Warehouse

    Blakely, R.J.

    1988-01-01

    Estimates of the depth to the Curie temperature isotherm in Nevada are in accordance with other regional geologic and geophysical information and together can be explained in the context of presentday tectonism. A method to estimate the depth extent of magnetic sources from the statistical properties of magnetic anomalies was applied to a statewide compilation of aeromagnetic data from Nevada. Basal depths of magnetic sources show no apparent correlation with the so-called magnetic quiet zone, which trends northerly through the eastern part of the state, or with basin-and-range topography. However, certain correlations with published heat flow measurements are apparent and suggest that undulations in basal depth of magnetic sources are related in part to undulations in the Curie temperature isotherm. For example, an area of shallow basal depth (<10 km) near Battle Mountain corresponds to an area of exceptionally high conductive heat flow and indicates a shallow depth to the Curie temperature isotherm in this region. A narrow zone of shallow basal depth extends south from the Battle Mountain area along the 118??W meridian to at least latitude 38??N, which also is a zone of historic surface offsets and high-magnitude earthquakes. The correspondence along the 118?? meridian of shallow basal depth, high heat flow, high lower crustal seismic velocities, attenuated P and S wave arrivals, historic faulting and, large earthquakes suggests that they each are related to an active north trending spreading zone in this part of the Basin and Range province. -Author

  5. Operational experiences of a commercial helicopter flown in a large metropolitan area

    NASA Technical Reports Server (NTRS)

    Dicarlo, D. J.

    1975-01-01

    A survey of commercial helicopter-operating experiences was conducted using a helicopter flight recorder in order to provide a basis for extending helicopter design and service-life criteria. These data are representative of 182 flight hours accumulated during 1414 flights comprised of the separate legs of the total route structure employed. The operating experiences are presented in terms of the time spent within different airspeed brackets, within the classifiable flight conditions of climb, en route, and descent, at various rates of climb and descent, and at different rotor rotational speeds. The results indicated that the helicopter spent a majority of the flight time at airspeeds either below 40 knots or above 100 knots. Rates of climb and descent were concentrated at values below 5.1 m/s (1000 ft/min) particularly for higher airspeeds. Normal acceleration experiences were low, both in the total number and peak value realized; however, an extremely large number of pitch angular-velocity experiences were noted. Rotor rotational speeds were normal with no occurrences above the upper red-line limit.

  6. An Examination of Radiation Induced Tensile Failure of Stressed and Unstressed Polymer Films Flown on MISSE-6

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K.; Sechkar, Edward A.

    2012-01-01

    Thin film polymers are used in many spacecraft applications for thermal control (multilayer insulation and sunshields), as lightweight structural members (solar array blankets, inflatable/deployable structures) and have been proposed for propulsion (solar sails). Polymers in these applications are often under a tensile load and are directly exposed to the space environment, therefore it is important to understand the effect of stress in combination with the environment on the durability of these polymer films. The purpose of the Polymer Film Tensile Experiment, flown as part of Materials International Space Station Experiment 6 (MISSE 6), was to expose a variety of polymer films to the low Earth orbital environment under both relaxed and tension conditions. This paper describes the results of post flight tensile testing of these samples.

  7. Results on Artemia cysts, lettuce and tobacco seeds in the biobloc 4 experiment flown aboard the Soviet biosatellite Cosmos 1129

    NASA Astrophysics Data System (ADS)

    Gaubin, Y.; Planel, H.; Gasset, G.; Pianezzi, B.; Delpoux, M.; Clegg, J.; Kovalev, E. E.; Nevzgodina, L. V.; Maximova, E. N.; Miller, A. T.

    Artemia cysts, lettuce and tobacco seeds were flown aboard the Cosmos 1129 for 19 days. A correlative method was used in order to determine the passage of cosmic heavy ions (HZE particles) through the biological test objects. This space flight resulted in a decrease on hatchability, nucleic acid and protein synthesis in hydrated Artemia cysts. HZE particle effects on plant cellular chromosomes are confirmed. In tobacco seeds, a stimulating effect on germination rate and a higher frequency of abnormalities were observed. Dormant biological objects are a very suitable material to study cosmic ray effects: these objects can be arranged in monolayers and sandwiched between visual track detectors in order to determine the passage of the cosmic heavy ions (HZE particles). On the other hand this method allows us to study effects of microgravity and those of the protonic component of cosmic rays in the objects not hit by the HZE particles.

  8. Results on artemia cysts, lettuce and tobacco seeds in the Biobloc 4 experiment flown aboard the Soviet biosatellite Cosmos 1129

    SciTech Connect

    Gaubin, Y.; Planel, H.; Gasset, G.; Pianezzi, B.

    1983-01-01

    The effects of space flight factors, in particular the heavy ion component of cosmic rays, on dormant stages of life forms were investigated as part of the Biobloc 4 experiment flown aboard the Cosmos 1129 biosatellite. Artemia cysts and seeds of tobacco and lettuce plants were placed in tubes and in monolayers sandwiched between layers of visual particle track detectors. Although Artemia cysts exposed in the dry state did not differ from ground controls, hydrated cysts exhibited a slight decrease in hatchability and reduced (C-14)O2 incorporation and protein and nucleic acid synthesis. For cysts held in the monolayers, hits by HZE particles were observed to stimulate emergence, hatching and survival. Higher proportions of chromosomal aberrations were found in lettuce seeds hit by HZE particles, while space flight produced a stimulatory effect on both germination rate and abnormality frequency in both hit and nonhit tobacco seeds. 9 references.

  9. Detection of DNA Damage by Space Radiation in Human Fibroblast Cells Flown on the International Space Station

    NASA Technical Reports Server (NTRS)

    Wu, Honglu; Lu, Tao; Wong, Michael; Feiveson, Alan; Stodieck, Louis; Karouia, Fathi; Zhang, Ye

    2016-01-01

    Although charged particles in space have been detected with radiation detectors on board the spacecraft since the early discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation has been difficult due to the low dose and low dose rate nature of the radiation environment, and the difficulty in separating the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in lymphocytes and early onset of cataracts, attributed primarily to the exposure to space radiation. In a recent experiment, human fibroblast cells were flown on the International Space Station (ISS). Cells were kept at 370 C in space and fixed on Days 3 and 14 after reaching orbit. After returning to the ground, the fixed cells were analyzed for phosphorylation of a histone protein H2AX by immunofluorescent staining of cells, which is a widely used biomarker for DNA double strand breaks. The 3-dimensional gamma-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed a small fraction of foci that were larger and displayed a track pattern in the flight samples in comparison to the ground controls. To confirm that the foci data from the flight study was actually induced from space radiation exposure, human fibroblast cells were exposed to low- and high-LET protons and high-LET Fe ions on the ground. High-LET protons and Fe ions were found to induce foci of the pattern that were observed in the flown cells.

  10. Detection of DNA damage by space radiation in human fibroblast cells flown on the International Space Station

    NASA Astrophysics Data System (ADS)

    Wu, Honglu; Feiveson, Alan; Karouia, Fathi; Stodieck, Louis; Zhang, Ye; Lu, Tao; Wong, Michael

    2016-07-01

    Although charged particles in space have been detected with radiation detectors on board the spacecraft since the early discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation has been difficult due to the low dose and low dose rate nature of the radiation environment, and the difficulty in separating the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in lymphocytes and early onset of cataracts, attributed primarily to the exposure to space radiation. In a recent experiment, human fibroblast cells were flown on the International Space Station (ISS). Cells were kept at 370C in space and fixed on Days 3 and 14 after reaching orbit. After returning to the ground, the fixed cells were analyzed for phosphorylation of a histone protein H2AX by immunofluorescent staining of cells, which is a widely used biomarker for DNA double strand breaks. The 3-dimensional γg-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed a small fraction of foci that were larger and displayed a track pattern in the flight samples in comparison to the ground controls. To confirm that the foci data from the flight study was actually induced from space radiation exposure, human fibroblast cells were exposed to low- and high-LET protons and high-LET Fe ions on the ground. High-LET protons and Fe ions were found to induce foci of the pattern that were observed in the flown cells.

  11. Advancements in understanding the aeromagnetic expressions of basin-margin faults—An example from San Luis Basin, Colorado

    USGS Publications Warehouse

    Grauch, V. J.; Bedrosian, Paul A.; Drenth, Benjamin J.

    2013-01-01

    Herein, we summarize and expand on an investigation of the sources of aeromagnetic anomalies related to faults along the eastern margin of the San Luis Basin, northern Rio Grande Rift, Colorado (Grauch et al., 2010). Similar to the faults examined in the central Rio Grande Rift, magnetic sources can be completely explained by tectonic juxtaposition and produce multiple, vertically stacked magnetic contrasts at individual faults. However, the geologic sources are different. They arise from both the sedimentary cover and the underlying bedrock rather than from stratified sediments. In addition, geologic evidence for secondary growth or destruction of magnetic minerals at the fault zone is lacking.

  12. Interpretation of high resolution aeromagnetic data for lineaments study and occurrence of Banded Iron Formation in Ogbomoso area, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Oladunjoye, Michael Adeyinka; Olayinka, Abel Idowu; Alaba, Mustapha; Adabanija, Moruffdeen Adedapo

    2016-02-01

    The quest for solid mineral resource as an alternative for oil income in Nigeria presents opportunity to diversify the resource base of the country. To fill some information gap on the long abandoned Ajase and Gbede Banded Iron Formations (BIF) in Ogbomoso area, Southwestern Nigeria, high resolution aeromagnetic data of Ogbomoso - Sheet 222 was interpreted; to provide a better understanding of the mode of occurrence of the iron ore and associated structural features and geologic model. These were accomplished by subjecting reduced-to-pole (RTP) residual aeromagnetic intensity map to various data filtering and processing involving total horizontal derivative, vertical derivative, Upward Continuation (UC), Downward Continuation (DC), Euler Deconvolution at different Spectral Indices (SI), and Analytical signal using Geosoft Oasis Montaj 6.4.2 (HJ) data processing and analysis software. The resultants maps were overlain, compared and or plotted on RTP residual aeromagnetic intensity map and or geological map and interpreted in relation to the surface geological map. Positive magnetic anomalies observed on the RTP residual aeromagnetic intensity map ranged from 2.1 to 94.0 nT and associated with contrasting basement rocks, Ajase and Gbede BIF; while negative magnetic anomalies varied between -54.7 nT and -2.8 nT and are associated with intrusive bodies. Interpreted lineaments obtained from total horizontal derivative map were separated into two categories namely ductile and brittle based on their character vis-à-vis magnetic anomalies on RTP intensity map. Whilst the brittle lineaments were interpreted as fracture or faults; the ductile lineaments were interpreted as folds or representing the internal fabric of the rock units. In addition prominent magnetic faults mainly due to offset of similar magnetic domain/gradient were also interpreted. The iron ore mineralization is distributed within the eastern portion of the study area with Ajase BIF at relatively greater

  13. Using High Resolution Aeromagnetic Data to Map Pervasive Folding in the Lithologically Indistinct Franciscan Coastal Belt

    NASA Astrophysics Data System (ADS)

    Phelps, G. A.; McLaughlin, R. J.; Jachens, R. C.; Wentworth, C. M.

    2008-12-01

    We use high-resolution aeromagnetic data to map magnetic bodies of graywacke of limited exposure that are either interbedded or structurally emplaced within broader areas of non-magnetic graywacke within the Franciscan Complex Coastal belt in northern California, which is bounded by the San Andreas Fault on the west and the Franciscan Complex Central belt on the south and east. Previous work has not extensively subdivided the Coastal belt because of the poor exposure and the fact that the exposed lithology is primarily graywacke indistinguishable in outcrop and hand sample and is thus difficult to map in the field. A hand-held magnetic susceptibility meter, however, in combination with thin-section analysis, reveals that some Coastal belt graywackes are magnetic. The thin-section analysis shows that the magnetic samples have a significant component of andesitic grains, whereas the non-magnetic samples do not. Further, the locations of these magnetic rocks correspond to elongate regions of high magnetic intensity (magnetic anomalies) kilometers to tens of kilometers in length. Previous 2D modeling showed that the bodies of magnetic graywacke can be modeled as a folded sheet, with antiformal limbs near or exposed at the surface and synformal limbs reaching a depth of about 1 km. Locations of edges of magnetic source bodies can be extracted from their magnetic anomalies. Near surface, steeply dipping edges lie beneath local maxima in the horizontal gradient of the magnetic potential surface. The edges are demarcated by locating discrete points along the local maxima. We connected these points, using an algorithm with a specific set of parameters, to delineate the edges of the magnetic graywacke bodies. Together with the previous 2D modeling, the anomalies and their edges show that the Coastal belt contains antiformal structures 5 to 20 km in length and 1.5 km in width, with a wavelength approximately 1.5 km. The modal direction of elongation is oriented approximately

  14. Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California; report on work done from December 1, 1980, to May 31, 1981

    USGS Publications Warehouse

    Couch, Richard W.; Gemperle, Michael

    1982-01-01

    Spectral analysis of aeromagnetic data collected over 6orth-central California during the summer of 1980 aided in determining magnetic-source bottom depths beneath the survey area. Five regions of shallow magnetic source bottom depths were detected: 1) Secret Spring Mountain and National Lava Beds Monument area, 2) the Mount Shasta area, 3) the Eddys Mountain area, 4) the Big Valley Mountains area, and 5) an area northeast of Lassen Peak. Except for the Eddys Mountain area, all regions exhibiting shallow depths are suggested to be due to elevated Curie-point isotherms. The elevated Curie-point depth beneath Secret Spring Mountain and the National Lava Beds Monument area was found to be 4-7 km BSL (Below Sea Level) and is an extension of a zone mapped beneath an area immediately to the north in Oregon. A similar depth was detected for the Mount Shasta area and the area northeast of Lassen Peak. A depth of 4-6 km BSL was detected beneath the Big Valley Mountains area. The shallow Curie-point depths beneath Secret Spring Mountain, Mount Shasta, Big Valley Mountains, and the area northeast of Lassen Peak appear to form a segmented Zone of elevated Curie-point isotherm depths which underlies the High Cascade Mountains and Modoc Plateau in north-central California. A small area of shallow depths to magnetic-source bottoms, 4-5 km BSL, beneath the Eddys Mountain area is attributed to a lithologic boundary rather than an elevated Curie-point isotherm. Deeper magnetic source bottom depths were mapped throughout the remainder of the study area, with depths greater than 9 km BSL indicated beneath Lassen Peak and greater than ii km BSL indicated beneath the Western Cascades, Eastern Klamath Mountains, and Great Valley.

  15. Calculating depths to shallow magnetic sources using aeromagnetic data from the Tucson Basin

    USGS Publications Warehouse

    Casto, Daniel W.

    2001-01-01

    Using gridded high-resolution aeromagnetic data, the performance of several automated 3-D depth-to-source methods was evaluated over shallow control sources based on how close their depth estimates came to the actual depths to the tops of the sources. For all three control sources, only the simple analytic signal method, the local wavenumber method applied to the vertical integral of the magnetic field, and the horizontal gradient method applied to the pseudo-gravity field provided median depth estimates that were close (-11% to +14% error) to the actual depths. Careful attention to data processing was required in order to calculate a sufficient number of depth estimates and to reduce the occurrence of false depth estimates. For example, to eliminate sampling bias, high-frequency noise and interference from deeper sources, it was necessary to filter the data before calculating derivative grids and subsequent depth estimates. To obtain smooth spatial derivative grids using finite differences, the data had to be gridded at intervals less than one percent of the anomaly wavelength. Before finding peak values in the derived signal grids, it was necessary to remove calculation noise by applying a low-pass filter in the grid-line directions and to re-grid at an interval that enabled the search window to encompass only the peaks of interest. Using the methods that worked best over the control sources, depth estimates over geologic sites of interest suggested the possible occurrence of volcanics nearly 170 meters beneath a city landfill. Also, a throw of around 2 kilometers was determined for a detachment fault that has a displacement of roughly 6 kilometers.

  16. Analysis of the Aeromagnetic Anomalies of the Auca Mahuida Volcano, Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Longo, L. M.; De Ritis, R.; Ventura, G.; Chiappini, M.

    2015-08-01

    We present the analysis of the subsurface structure of the Auca Mahuida volcano based on high-resolution aeromagnetic data integrated with the available geological information. Most of the detected magnetic anomalies have a dipolar structure opposite to that of the present geomagnetic field. According to the available geochronological data and paleomagnetic measurements, the source bodies of Auca Mahuida mainly emplaced in the Matuyama reverse polarity chron. The Reduction-to-the-Pole map confirms that the magnetization direction is mainly reverse with only few anomalies normally magnetized. Two opposite, coexisting polarities do not allow to fully remove the dipolar character of the field in the Reduction-to-the-Pole transformation. Therefore, we model the measured anomaly field by applying analytical techniques that are independent of the magnetization direction. The obtained anomaly strikes and source geometries indicate an emplacement of intrusive bodies controlled by the regional faults affecting the Auca Mahuida basement and the sedimentary successions of the Neuquén basin. Magma upraised along these faults and fractures feeding the volcanic activity and subsequently crystallized. The averaged power spectrum and Euler Deconvolution indicate source depths consistent with those of the intrusions recognized in wells. Borehole data highlight the widespread presence of intrusive bodies below the Auca Mahuida central crater and the peripheral sectors at depth of 2 km below sea level. These bodies have played a major role in the thermal maturation of hydrocarbons and in the subsequent accumulation of oil below the volcano. The obtained results shed light on the Auca Mahuida feeding system and on the intrusions geometry, also pointing out the effectiveness of the magnetic prospecting in the oil industry even in presence of strong remanent magnetization.

  17. Analysis of the Aeromagnetic Anomalies of the Auca Mahuida Volcano, Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Longo, L. M.; De Ritis, R.; Ventura, G.; Chiappini, M.

    2016-10-01

    We present the analysis of the subsurface structure of the Auca Mahuida volcano based on high-resolution aeromagnetic data integrated with the available geological information. Most of the detected magnetic anomalies have a dipolar structure opposite to that of the present geomagnetic field. According to the available geochronological data and paleomagnetic measurements, the source bodies of Auca Mahuida mainly emplaced in the Matuyama reverse polarity chron. The Reduction-to-the-Pole map confirms that the magnetization direction is mainly reverse with only few anomalies normally magnetized. Two opposite, coexisting polarities do not allow to fully remove the dipolar character of the field in the Reduction-to-the-Pole transformation. Therefore, we model the measured anomaly field by applying analytical techniques that are independent of the magnetization direction. The obtained anomaly strikes and source geometries indicate an emplacement of intrusive bodies controlled by the regional faults affecting the Auca Mahuida basement and the sedimentary successions of the Neuquén basin. Magma upraised along these faults and fractures feeding the volcanic activity and subsequently crystallized. The averaged power spectrum and Euler Deconvolution indicate source depths consistent with those of the intrusions recognized in wells. Borehole data highlight the widespread presence of intrusive bodies below the Auca Mahuida central crater and the peripheral sectors at depth of 2 km below sea level. These bodies have played a major role in the thermal maturation of hydrocarbons and in the subsequent accumulation of oil below the volcano. The obtained results shed light on the Auca Mahuida feeding system and on the intrusions geometry, also pointing out the effectiveness of the magnetic prospecting in the oil industry even in presence of strong remanent magnetization.

  18. The Northern Boundary of the Michoacan Block: As Inferred From Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Rosas-Elguera, J.; Lopez Loera, H.; Fregoso, E.; Maciel Flores, R.; Peña, L.; Alatorre-Zamora, M. A.

    2015-12-01

    The western part of the Guerrero terrane is comprised of the Jalisco and Michoacan Blocks (Rosas-Elguera et al., 1996 and references therein), a fault-bounded crustal blocks at western of Mexico. The Michoacan block is bounded by the N-NE segment of the Rio Balsas in the east, and the Colima graben in the west, the Chapala-Oaxaca fault to the north, and the Middle America Trench to the south. Northern boundary is formed with the Chapala-Oaxaca fault zone (Harrison y Johnson, 1985). The Cotija half-graben is the end-tip of this fault zone. A combined radiometric and paleomagnetic analyses in the Cotija half-graben were carried out (Rosas-Elguera, et al, 2003). Radiometric dates between 31.60 and 8.39 Ma confirm both the southern extension of the Sierra Madre Occidental and the early mafic Tans-Mexican Volcanic Belt succession at the northern part of the Michoacan block. Paleomagnetic data indicate a counterclockwise rotation of ~ 24° about a vertical axis for the Michoacan block. The Michoacan-Guanajuato Volcanic Field forms an area of extensive monogenetic volcanism. This volcanic field contains more than 1000 eruptive centers distributed over an area of 40,000 Km2. The Chapala-Oaxaca fault zone separates the northern MGVF and the southern MGVF. Hasenaka and Carmichael (1987) recognized three different petrologic associations in the MGVF: calc-alkaline rocks typical arc characteristic, K2O-rich alkaline rocks with relatively high MgO contents and TiO2-rich alkaline rocks with relatively low MgO contents. We present the aeromagnetic results (after Consejo de Recursos Minerales, 1999) which suggest a clear relationship between the geologic features and the magnetic response.

  19. Analysis of aeromagnetic anomalies; mapping of Curie isothermal surface at Long Valley, California

    SciTech Connect

    Miyazaki, Y.

    1985-01-01

    The objective of this study was to gain an understanding of the nature and extent of the Long Valley geothermal system at depth. Airborne magnetic data was used to calculate the Curie isotherm depth for mapping the underground temperature distribution using a spectral analysis and Marquardt non-linear least squares method. Other geophysical and topographic data, such as gravity, Landsat and Digital Terrain Model combined with aeromagnetic data were also used to understand the tectonic structure at depth. These data were geometrically corrected and registered to the basic UTM map, and displayed with a technique of computer color-graphics. In spectral analysis, the Maximum Entropy power spectrum was used to estimate the Curie isotherm depth rather than FET spectrum because this can produce high resolution with accurate frequency and power estimates even for short data samples. The result of magnetic analysis showed that the east-half of Long Valley caldera is cool with curie depth of about 8 km, while the west-half is very hot with Curie depth of about 4.5 km. These estimates are reasonable depths from the surface heat flow data, and are also consistent with the temperature distribution obtained by deep hole data. This fact suggests that the Curie depth analysis is a very encouraging technique and tool for the geothermal exploration. The superimposed image data of geophysical and topographic data suggested that Hilton Creek fault extends northward all the way to Bridgeport Valley. The preliminary result showed that east of the Hilton Creek fault it is cool while to the west it is hot. This may be explained by the flow of cool ground-water through the deep fracture zones of the Hilton Creek fault.

  20. Curie temperature isotherm analysis and tectonic implications of aeromagnetic data from Nevada

    SciTech Connect

    Blakely, R.J.

    1988-10-10

    Estimates of the depth to the Curie temperature isotherm in Nevada are in accordance with other regional geologic and geophysical information and together can be explained in the context of present-day tectonism. A method to estimate the depth extent of magnetic sources from the statistical properties of magnetic anomalies was applied to a statewide compilation of aeromagnetic data from Nevada. Basal depths of magnetic sources show no apparent correlation with the so-called magnetic quiet zone, which trends northerly through the eastern part of the state, or with basin-and-range topography. However, certain correlations with published heat flow measurements are apparent and suggest that undulations in basal depth of magnetic sources are related in part to undulations in the Curie temperature isotherm. For example, an area of shallow basal depth (< 10 km) near Battle Mountain corresponds to an area of exceptionally high conductive heat flow and indicates a shallow depth to the Curie temperature isotherm in this region. A narrow zone of shallow basal depth extends south from the Battle Mountain area along the 118/degrees/W meridian to at least latitude 38/degrees/N, which also is a zone of historic surface offsets and high-magnitude earthquakes. The correspondence along the 118/degrees/ meridian of shallow basal depth, high heat flow, high lower crustal seismic velocities, attenuated P and S wave arrivals, historic faulting, and large earthquakes suggests that they each are related to an active north trending spreading zone in this part of the Basin and Range province. 83 references.

  1. Precambrian basement geologic map of Montana; an interpretation of aeromagnetic anomalies

    USGS Publications Warehouse

    Sims, P.K.; O'Neill, J. M.; Bankey, Viki; Anderson, E.

    2004-01-01

    Newly compiled aeromagnetic anomaly data of Montana, in conjunction with the known geologic framework of basement rocks, have been combined to produce a new interpretive geologic basement map of Montana. Crystalline basement rocks compose the basement, but are exposed only in the cores of mountain ranges in southwestern Montana. Principal features deduced from the map are: (1) A prominent northeast-trending, 200-km-wide zone of spaced negative anomalies, which extends more than 700 km from southwestern Montana's Beaverhead Mountains to the Canadian border and reflects suturing of the Archean Mexican Hat Block against the Archean Wyoming Province along the Paleoproterozoic Trans-Montana Orogen (new name) at about 1.9-1.8 Ga; (2) North-northwest-trending magnetic lows in northeastern Montana, which reflect the 1.9-1.8 Ga Trans-Hudson Orogen and truncate the older Trans-Montana Zone; and (3) Subtle northwest- and west-trending negative anomalies in central and western Montana, which represent the northernmost segment of brittle-ductile transcurrent faults of the newly recognized Mesoproterozoic Trans-Rocky Mountain fault system. Structures developed in the Proterozoic provided zones of crustal weakness reactivated during younger Proterozoic and Phanerozoic igneous and tectonic activity. For example, the Trans-Montana Zone guided basement involved thrust faulting in southwestern Montana during the Sevier Orogeny. The Boulder Batholith and associated ore deposits and the linear belt of alkaline intrusions to the northeast were localized along a zone of weakness between the Missouri River suture and the Dillon shear zone of the Trans-Montana Orogen. The northwest-trending faults of Trans-Rocky Mountain system outline depocenters for sedimentary rocks in the Belt Basin. This fault system provided zones of weakness that guided Laramide uplifts during basement crustal shortening. Northwest-trending zones have been locally reactivated during Neogene basin-range extension.

  2. Shallow-source aeromagnetic anomalies observed over the West Antarctic Ice Sheet compared with coincident bed topography from radar ice sounding - New evidence for glacial "removal" of subglacially erupted late Cenozoic rift-related volcanic edifices

    USGS Publications Warehouse

    Behrendt, John C.; Blankenship, D.D.; Morse, D.L.; Bell, R.E.

    2004-01-01

    Aeromagnetic and radar ice sounding results from the 1991-1997 Central West Antarctica (CWA) aerogeophysical survey over part of the West Antarctic Ice Sheet (WAIS) and subglacial area of the volcanically active West Antarctic rift system have enabled detailed examination of specific anomaly sources. These anomalies, previously interpreted as caused by late Cenozoic subglacial volcanic centers, are compared to newly available glacial bed-elevation data from the radar ice sounding compilation of the entire area of the aeromagnetic survey to test this hypothesis in detail. We examined about 1000 shallow-source magnetic anomalies for bedrock topographic expression. Using very conservative criteria, we found over 400 specific anomalies which correlate with bed topography directly beneath each anomaly. We interpret these anomalies as indicative of the relative abundance of volcanic anomalies having shallow magnetic sources. Of course, deeper source magnetic anomalies are present, but these have longer wavelengths, lower gradients and mostly lower amplitudes from those caused by the highly magnetic late Cenozoic volcanic centers. The great bulk of these >400 (40-1200-nT) anomaly sources at the base of the ice have low bed relief (60-600 m, with about 80%10 million years ago. Eighteen of the anomalies examined, about half concentrated in the area of the WAIS divide, have high-topographic expression (as great as 400 m above sea level) and high bed relief (up to 1500 m). All of these high-topography anomaly sources at the base of the ice would isostatically rebound to elevations above sea level were the ice removed. We interpret these 18 anomaly sources as evidence of subaerial eruption of volcanoes whose topography was protected from erosion by competent volcanic flows similar to prominent volcanic peaks that are exposed above the surface of the WAIS. Further, we infer these volcanoes as possibly erupted at a time when the WAIS was absent. In contrast, at the other extreme

  3. Geologic implications of topographic, gravity, and aeromagnetic data in the northern Yukon-Koyukuk province and its borderlands, Alaska

    USGS Publications Warehouse

    Cady, J.W.

    1989-01-01

    The northern Yukon-Koyukuk province is characterized by low elevation and high Bouguer gravity and aeromagnetic anomalies in contrast to the adjacent Brooks Range and Ruby geanticline. Using newly compiled digital topographic, gravity, and aeromagnetic maps, the province is divided into three geophysical domains. The Koyukuk domain, which is nearly equivalent to the Koyukuk lithotectonic terrane, is a horseshoe-shaped area, open to the south, of low topography, high gravity, and high-amplitude magnetic anomalies caused by an intraoceanic magmatic arc. The Angayucham and Kanuti domains are geophysical subdivisions of the Angayucham lithotectonic terrane that occur along the northern and southeastern margins of the Yukon-Koyukuk province, where oceanic rocks have been thrust over continental rocks of the Brooks Range and Ruby geanticline. The modeling supports, but does not prove, the hypothesis that the crust of the Kobuk-Koyukuk basin is 32-35 km thick, consisting of a tectonically thickened section of Cretaceous volcanic and sedimentary rocks and older oceanic crust. -from Author

  4. Geothermal reconnaissance of the area between Marsa Alam and Ras Banas, northern Red Sea, Egypt, using aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Saada, Saada A.

    2016-06-01

    Aeromagnetic data of the area between Marsa Alam and Ras Banas were interpreted to estimate the Curie point isotherm, investigate the geothermal gradient and to determine its surface heat flow. Appling spectral analysis and 2-D inverse modeling techniques to aeromagnetic anomalies has provided equitable promising geological results, useful to further geothermal exploration. Spectral analysis indicates that, the area is underlined by an average Curie-point depth of about 10.58 km. This implies an average thermal heat flow (137 mW/m2) greater than the average heat flow of the Red Sea margins (116 mW/m2). The investigated area was divided into three subregions and the average depth to centroid was estimated for each subregion. 2-D inverse modeling technique indicated that the magnetic sources can be interpreted by a set of dykes dipping to the NE and SW. The integration of radially power spectrum and 2-D inverse modeling was used to estimating the depths to the bottom of these magnetic bodies (equivalent to the Curie-point depth). It indicated a general decrease from 24 to 10 km from west to east toward the Red Sea rifting zone. The calculated surface heat flow increases from 55 mW/m2 to >150 mW/m2 in the same direction. Consequently, the offshore area between Ras Banas and Marsa Alam is a promising area for further exploration of geothermal resources.

  5. Identifying buried segments of active faults in the northern Rio Grande Rift using aeromagnetic, LiDAR,and gravity data, south-central Colorado, USA

    USGS Publications Warehouse

    Ruleman, Cal; Grauch, V. J.

    2013-01-01

    Combined interpretation of aeromagnetic and LiDAR data builds on the strength of the aeromagnetic method to locate normal faults with significant offset under cover and the strength of LiDAR interpretation to identify the age and sense of motion of faults. Each data set helps resolve ambiguities in interpreting the other. In addition, gravity data can be used to infer the sense of motion for totally buried faults inferred solely from aeromagnetic data. Combined interpretation to identify active faults at the northern end of the San Luis Basin of the northern Rio Grande rift has confirmed general aspects of previous geologic mapping but has also provided significant improvements. The interpretation revises and extends mapped fault traces, confirms tectonic versus fluvial origins of steep stream banks, and gains additional information on the nature of active and potentially active partially and totally buried faults. Detailed morphology of surfaces mapped from the LiDAR data helps constrain ages of the faults that displace the deposits. The aeromagnetic data provide additional information about their extents in between discontinuous scarps and suggest that several totally buried, potentially active faults are present on both sides of the valley.

  6. Volcanic rocks and subglacial volcanism beneath the West Antarctic Ice Sheet in the West Antarctic Rift System, (WAIS) from aeromagnetic and radar ice sounding - Thiel Subglacial Volcano as possible source of the ash layer in the WAISCORE

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.

    2012-12-01

    Radar ice sounding and aeromagnetic surveys reported over the West Antarctic Ice Sheet (WAIS) have been interpreted as evidence of subglacial volcanic eruptions over a very extensive area (>500,000 km2 ) of the volcanically active West Antarctic rift system interpreted as caused by subglacial volcanic rocks. Several active volcanoes have shown evidence of eruption through the WAIS and several other active volcanoes are present beneath the WAIS reported from radar and aeromagnetic data. Five-kilometer spaced coincident aeromagnetic and radar ice sounding surveys since 1990 provide three dimensional characterization of the magnetic field and bed topography beneath the ice sheet. These 5-50-km-width, semicircular magnetic anomalies range from 100->1000 nT as observed ~1 km over the 2-3 km thick ice have been interpreted as evidence of subglacial eruptions. Comparison of a carefully selected subset of ~400 of the >1000 high-amplitude anomalies in the CWA survey having topographic expression at the glacier bed, showed >80% had less than 200-m relief. About 18 high-amplitude subglacial magnetic sources also have high topography and bed relief (>600 m) interpreted as subaerially erupted volcanic peaks when the WAIS was absent, whose competent lava flows protected their edifices from erosion. All of these would have high elevation above sea-level, were the ice removed and glacial rebound to have occurred. Nine of these subaerially erupted volcanoes are concentrated in the WAIS divide area. Behrendt et al., 1998 interpreted a circular ring of positive magnetic anomalies overlying the WAIS divide as caused by a volcanic caldera. The area is characterized by high elevation bed topography. The negative regional magnetic anomaly surrounding the caldera anomalies was interpreted as the result of a shallow Curie isotherm. High heat flow inferred from temperature logging in the WAISCORE (G. Clow 2012, personal communication; Conway, 2011) and a prominent volcanic ash layer in the

  7. Digital data from the Questa-San Luis and Santa Fe East helicopter magnetic surveys in Santa Fe and Taos Counties, New Mexico, and Costilla County, Colorado

    USGS Publications Warehouse

    Bankey, Viki; Grauch, V.J.S.; Drenth, B.J.; ,

    2006-01-01

    This report contains digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during high-resolution aeromagnetic surveys in southern Colorado and northern New Mexico in December, 2005. One survey covers the eastern edge of the San Luis basin, including the towns of Questa, New Mexico and San Luis, Colorado. A second survey covers the mountain front east of Santa Fe, New Mexico, including the town of Chimayo and portions of the Pueblos of Tesuque and Nambe. Several derivative products from these data are also presented as grids and images, including reduced-to-pole data and data continued to a reference surface. Images are presented in various formats and are intended to be used as input to geographic information systems, standard graphics software, or map plotting packages.

  8. Application of high resolution aeromagnetic data for basement topography mapping of Siluko and environs, southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Osinowo, Olawale O.; Akanji, Adesoji O.; Olayinka, Abel I.

    2014-11-01

    The discovery of hydrocarbon in commercial quantity in the Niger Delta, southern Nigeria, has since the early fifties shifted the attention of exploration/active geological studies from the Dahomey basin and the adjacent basement terrain in south-western Nigeria towards the south and this has left some gaps in information required for the discovery and exploitation of the economic potential of the region. This study mapped the Siluko transition zone in south-western Nigeria in terms of structures, geometry and basement topography with the object of providing requisite geological information that will engender interest in the exploration and exploitation of the numerous economic potentials of south-western part of Nigeria. Acquired high resolution aeromagnetic data were filtered, processed and enhanced, the resultant data were subjected to qualitative and quantitative magnetic interpretation, depth weighting analyses and modelling to generate the subsurface basement topography across the study area. The obtained results indicate regions of high and low magnetic anomalies with residual magnetic intensity values ranging from -100.8 nT to 100.9 nT. Euler Deconvolution indicates generally undulating basement topography with depth range of 125-1812 m. The basement relief is generally gentle and flat lying within the basement terrain with depth ranging from 125 to 500 m. However the sedimentary terrain is undulating and generally steeps south, down the basin with depth range of 300-1812 m. A basement topography model of the magnetic data constrained by Euler solutions correlate positively with the geology of the study area and indicates a generally increasing sedimentary deposits' thickness southward toward the western part of Dahomey basin. The revealed basement topography and structures as well as the delineated direction of continuous increase in thickness of sedimentary deposit provide insight to the controlling factor responsible for tar sand deposit and bitumen

  9. Aeromagnetic interpretation in the south-central Zimbabwe Craton: (reappraisal of) crustal structure and tectonic implications

    NASA Astrophysics Data System (ADS)

    Ranganai, Rubeni T.; Whaler, Kathryn A.; Ebinger, Cynthia J.

    2015-12-01

    Regional aeromagnetic data from the south-central Zimbabwe Craton have been digitally processed and enhanced for geological and structural mapping and tectonic interpretation integrated with gravity data, to constrain previous interpretations based on tentative geologic maps and provide new information to link these structural features to known tectonic events. The derived maps show excellent correlation between magnetic anomalies and the known geology, and extend lithological and structural mapping to the shallow/near subsurface. In particular, they reveal the presence of discrete crustal domains and several previously unrecognised dykes, faults, and ultramafic intrusions, as well as extensions to others. Five regional structural directions (ENE, NNE, NNW, NW, and WNW) are identified and associated with trends of geological units and cross-cutting structures. The magnetic lineament patterns cut across the >2.7 Ga greenstone belts, which are shown by gravity data to be restricted to the uppermost 10 km of the crust. Therefore, the greenstone belts were an integral part of the lithosphere before much of the upper crustal (brittle) deformation occurred. Significantly, the observed magnetic trends have representatives craton-wide, implying that our interpretation and inferences can be applied to the rest of the craton with confidence. Geological-tectonic correlation suggests that the interpreted regional trends are mainly 2.5 Ga (Great Dyke age) and younger, and relate to tectonic events including the reactivation of the Limpopo Belt at 2.0 Ga and the major regional igneous/dyking events at 1.8-2.0 Ga (Mashonaland), 1.1 Ga (Umkondo), and 180 Ma (Karoo). Thus, their origin is here inferred to be inter- and intra-cratonic collisions and block movements involving the Zimbabwe and Kaapvaal Cratons and the Limpopo Belt, and later lithospheric heating and extension associated with the break-up of Gondwana. The movements produced structures, or reactivated older fractures

  10. New sonic shockwave multi-element sensors mounted on a small airfoil flown on F-15B testbed aircraft

    NASA Technical Reports Server (NTRS)

    1996-01-01

    An experimental device to pinpoint the location of a shockwave that develops in an aircraft flying at transonic and supersonic speeds was recently flight-tested at NASA's Dryden Flight Research Center, Edwards, California. The shock location sensor, developed by TAO Systems, Hampton, Va., utilizes a multi-element hot-film sensor array along with a constant-voltage anemometer and special diagnostic software to pinpoint the exact location of the shockwave and its characteristics as it develops on an aircraft surface. For this experiment, the 45-element sensor was mounted on the small Dryden-designed airfoil shown in this illustration. The airfoil was attached to the Flight Test Fixture mounted underneath the fuselage of Dryden's F-15B testbed aircraft. Tests were flown at transonic speeds of Mach 0.7 to 0.9, and the device isolated the location of the shock wave to within a half-inch. Application of this technology could assist designers of future supersonic aircraft in improving the efficiency of engine air inlets by controlling the shockwave, with a related improvement in aircraft performance and fuel economy.

  11. Post-Flight Analysis of Selected Fluorocarbon and Other Thin Film Polymer Specimens Flown on MISSE-5

    NASA Technical Reports Server (NTRS)

    DeGroh, Kim; Finckenor, Miria; Minton, Tim; Brunsvold, Amy; Pippin, Gary

    2007-01-01

    Twenty thin film specimens were flown on M1SSE-5 as a cooperative effort between several organizations. This presentation will report results of initial inspections and post-flight measurements of the optical properties and recession of these materials due to the approx.13 month exposure period on the exterior of the International Space Station. These specimens were located on the "anti-solar" side of the MISSE-5 container and received a low number of Equivalent Sun Hours of solar UV exposure. Profilometry and/or ATF measurements will be conducted to determine thickness changes and atomic oxygen-induced recession rates Six of the specimens were covered with thin Kapton films, 0.1 and 0.3 mil in thickness. The 0.1 mil Kapton was almost completely eroded, suggesting that the atomic oxygen fluence is <8 x 10(exp 19) atoms/sq cm, similar to levels experienced during Space Shuttle materials experiments in the 1980's and 1990's. A comparison of results from MISSE-5 and Space Shuttle experiments will be included for those materials common to both the short and long-term exposures.

  12. Redesign of a Variable-Gain Output Feedback Longitudinal Controller Flown on the High-Alpha Research Vehicle (HARV)

    NASA Technical Reports Server (NTRS)

    Ostroff, Aaron J.

    1998-01-01

    This paper describes a redesigned longitudinal controller that flew on the High-Alpha Research Vehicle (HARV) during calendar years (CY) 1995 and 1996. Linear models are developed for both the modified controller and a baseline controller that was flown in CY 1994. The modified controller was developed with three gain sets for flight evaluation, and several linear analysis results are shown comparing the gain sets. A Neal-Smith flying qualities analysis shows that performance for the low- and medium-gain sets is near the level 1 boundary, depending upon the bandwidth assumed, whereas the high-gain set indicates a sensitivity problem. A newly developed high-alpha Bode envelope criterion indicates that the control system gains may be slightly high, even for the low-gain set. A large motion-base simulator in the United Kingdom was used to evaluate the various controllers. Desired performance, which appeared to be satisfactory for flight, was generally met with both the low- and medium-gain sets. Both the high-gain set and the baseline controller were very sensitive, and it was easy to generate pilot-induced oscillation (PIO) in some of the target-tracking maneuvers. Flight target-tracking results varied from level 1 to level 3 and from no sensitivity to PIO. These results were related to pilot technique and whether actuator rate saturation was encountered.

  13. Alterations of leaf cell ultrastructures and AFLP DNA profiles in Earth-grown tomato plants propagated from long-term six years Mir-flown seeds

    NASA Astrophysics Data System (ADS)

    Liu, Min; Xue, Huai; Pan, Yi; Zhang, Chunhua; Lu, Jinying

    Leaf cell ultrastructures and DNA variations in the firstand the second-generation of Earthgrown tomato (Lycopersicon esculentun Mill) plants that had been endured a long-term six years spaceflight in the Mir were compared to their ground-based control plants, under observations with a Transmission Electron Microscope and the Amplification Fragment Length Polymorphism (AFLP) analysis. For alterations in the morphological ultrastructures, one plant among the 11 first-generation plants generated from 30 Mir-flown seeds had a three-layered palisade cell structure, while other 10 first-generation plants and all ground-based controls had one-layered palisade cell structure in leaves. Starch grains were larger and in clusters, numbers of starch grains increased in the chloroplasts in the Mir-flown plants. Leaf cells became contracted and deformed, and cell shape patterns were different in the Mir-flown plants. For the leaf genomic DNA alterations, 34 DNA bands were polymorphic with a 1.32% polymorphism among 2582 DNA bands in the first-generation Mir-flown plants. Band types in the spaceflight treated plants were also different from those in the ground-based control. Of 11 survived first-generation plants, 7 spaceflight treated plants (Plant Nos. 1-6 and No. 9) had a same 7 polymorphic bands and a same 0.27%DNA mutation. The DNA mutation rate was greatest in Plants No.10 and No.7 (0.90% and 0.94%), less in Plant No.11 (0.31%) and least in Plant No.8 (0.20%). For the 38 send-generation plants propagated from the No. 5 Mir-flown seed, 6 DNA bands were polymorphic with a 0.23% polymorphism among 2564 amplified DNA bands. Among those 38 second-generation plants amplified by primer pair (E4: ACC, M8: CTT), one DNA band disappeared in 29 second-generation plants and in the original Mir-flown No. 5 plant, compared to the ground-base controls. Among the 38 second-generation plants generated from the Mir-flown No. 5 seed, the DNA band types of 29 second-generation plants were

  14. Inversion of Airborne Electromagnetic Survey Data, Styx River Area, Alaska

    NASA Astrophysics Data System (ADS)

    Kass, A.; Minsley, B. J.; Smith, B. D.; Burns, L.; Emond, A.

    2014-12-01

    A joint effort by the US Geological Survey (USGS) and the Alaska Division of Geological & Geophysical Surveys (DGGS) aims to add value to public domain airborne electromagnetic (AEM) data, collected in Alaska, through the application of newly developed advanced inversion methods to produce resistivity depth sections along flight lines. Derivative products are new geophysical data maps, interpretative profiles and displays. An important task of the new processing is to facilitate calibration or leveling between adjacent surveys flown with different systems in different years. The new approach will facilitate integration of the geophysical data in the interpretation and construction of geologic framework, resource evaluations and to geotechnical studies. Four helicopter airborne electromagnetic (AEM) surveys have been flown in the Styx River area by the DGGS; Styx River, Middle Styx, East Styx, and Farewell. The Styx River flown in 2008 and Middle Styx in flown 2013, cover an area of 2300 square kilometers. These data consist of frequency-domain DIGHEM V surveys which have been numerically processed and interpreted to yield a three-dimensional model of electrical resistivity. We describe the numerical interpretation methodology (inversion) in detail, from quality assessment to interpretation. We show two methods of inversion used in these datasets, deterministic and stochastic, and describe how we use these results to define calibration parameters and assess the quality of the datasets. We also describe the difficulties and procedures for combining datasets acquired at different times.

  15. Preliminary results from coupled modeling of gravity and aeromagnetic data in the Waukesha Fault area of southeastern Wisconsin

    NASA Astrophysics Data System (ADS)

    Skalbeck, J. D.; Couch, J. N.; Roy, D. M.

    2003-12-01

    Increased concerns recently about the quantity and quality of groundwater resources in Wisconsin have brought about the need for better understanding of the subsurface geologic lithology and structure that controls groundwater flow. Concern centers on excessive drawdown in the deep sandstone aquifer system throughout southeastern Wisconsin and its relation to increasing levels of total dissolved solids and radium in some municipal supply wells. It is possible that preferential flow paths influence the circulation of groundwater to these wells and their vulnerability to contamination. The largest feature that could channel vertical and horizontal flow at the regional scale is the northeast trending Waukesha fault zone that intersects the main pumping center at Waukesha. The normal vertical displacement along the Waukesha Fault produces strong gravity and aeromagnetic anomalies coincident with the northeast trend of the fault. Previous gravity modeling studies associated with the fault are generally unconstrained yielding results with wide variation in fault geometry and vertical fault offset. Reasonable model fits were obtained with fault dip ranging from 10o to 85o with vertical offset ranging from 500 to 700 m. This study provides well-constrained results from coupled modeling of gravity and aeromagnetic (potential fields) data and incorporation of lithologic depths from the lithology database used to construct a regional numerical model for southeastern Wisconsin. We also utilized depth information from the only well (USGS Test Well, Zion, IL) that penetrates the entire Cambrian-Ordovician aquifer system to reach the Precambrian basement on the down-thrown (southeast) block of the fault. Preliminary modeling of gravity and aeromagnetic data along two profiles suggests vertical offset of Precambrian basement from 700 to 800 m along a normal fault with a 60o southeast dip. Based on thickness of the Cambrian Mount Simon sandstone, preliminary results also suggest

  16. Possible Effects on the Stability of the West Antarctic Ice Sheet (WAIS) and Associated Sea-level Rise From Active-Recent Subglacial Volcanism Interpreted from Aeromagnetic and Radar Ice-sounding Observations

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.

    2009-12-01

    Aeromagnetic profiles (>10,000 km) acquired in the early 1960s over the West Antarctic Ice Sheet (WAIS) combined with coincident aeromagnetic and radar ice sounding in 1978-79 indicated numerous high-amplitude, shallow-source, magnetic anomalies over a very extensive area of the volcanically active West Antarctic rift system interpreted as caused by subglacial volcanic rocks. These early aerogeophysical surveys defined this area as >500,000 km2. Five-kilometer spaced coincident aeromagnetic and radar ice sounding surveys since 1990 provide three dimensional characterization of the magnetic field and bed topography beneath the ice sheet. These 5-50-km width, semicircular magnetic anomalies range from 100->1000 nT as observed ~1 km over the 2-3 km thick ice. Behrendt et al, (2005, 2008) interpreted these anomalies as indicating >1000 "volcanic centers". requiring high remanent normal (and at least 10% reversed) magnetizations in the present field direction. These data have shown that >80% of the anomaly sources at the bed of the WAIS, have been modified by the moving ice into which they were injected, requiring a younger age than the WAIS (about 25 Ma). Behrendt et al., (1994; 2007) conservatively estimated >1 x 106 km3 volume of volcanic sources to account for the area of the "volcanic center" anomalies. Although exposed volcanoes surrounding the WAIS extend in age to ~34 m.y., Mt Erebus, (<1 Ma) Mt. Melbourne, (<0.26 Ma), and Mt. Takahae (<0.1 Ma) are examples of exposed active volcanoes in the WAIS area. However, the great volume of volcanic centers is buried beneath the WAIS. If only a very small percentage of these >1000 volcanic, magnetic-anomaly sources are active today, or in the recent past, in the drainage area of the WAIS, subglacial volcanism may still have a significant effect on the dynamics of the WAIS. Interpreted active subglacial volcanism is revealed by aerogeophysical data reported by Blankenship et al., (1993, Mt. Casertz), and Corr and Vaughan

  17. Space Environment Effects on Stability of Medications Flown on Space Shuttles and the International Space Station (ISS)

    NASA Technical Reports Server (NTRS)

    Daniels, Vernie; Du, Jianping; Crady, Camille; Satterfield, Rick; Putcha, Lakshmi

    2007-01-01

    The purpose is to assess physical and chemical degradation of select pharmaceutical formulations from the Shuttle and ISS medical kits. Eleven pharmaceuticals dispensed as different dosage forms were selected based on their physical / chemical characteristics and susceptibility to environmental factors such as, temperature, humidity and light sensitivity. When available, ground-controls of the study medications with matching brand and lot numbers were used for comparison. Samples retrieved from flight were stored along with their matching controls in a temperature and humidity controlled environmental chamber. Temperature, humidity, and radiation data from the Shuttle and ISS were retrieved from onboard HOBO U12 Temp/RH Data Loggers, and from passive dosimeters. Physical and chemical analyses of the pharmaceuticals were conducted using validated United States Pharmacopeia (USP) methods. Results indicated degradation of 6 of the 11 formulations returned from space flights. Four formulations, Amoxicillin / Clavulanate, promethazine, sulfamethoxazole / trimethoprim, and ciprofloxacin tablets depicted discoloration after flight. Chemical content analyses using High or Ultra Performance Liquid Chromatography (HPLC / UPLC) methods revealed that dosage forms of Amoxicillin / Clavulanate, promethazine, sulfamethoxazole / trimethoprim, lidocaine, ciprofloxacin and mupirocin contained less than 95% of manufacturer s labeled claim of active drug compound. Shuttle and ISS environments affect stability and shelf life of certain mediations flown on these missions. Data analysis is in progress to examine the effect of specific space flight environmental factors on pharmaceutical stability. The degradation profiles generated from ground studies in analog environments will be useful in establishing predictive shelf-life profiles for medications intended for use during long-term space exploration missions.

  18. Further evidence of fracture-zone induced tectonic segmentation of the Antarctic Peninsula from detailed aeromagnetic anomalies.

    SciTech Connect

    Johnson, A.C.; Swain, C.J.

    1995-07-15

    Aeromagnetic anomaly data collected between 67{degrees}S and 70{degrees}S crossing the Antarctic Peninsula and adjacent offshore areas show a prominent NW-SE trend in the magnetic fabric. Apparent lateral offsets, previously recognized in the Pacific Margin Anomaly, have been mapped in detail and are shown to be much smaller than previously suggested. A 35 km wide zone of subdued magnetic anomalies at the Western edge of the Pacific Margin Anomaly, bounded by these apparent offsets, is interpreted as a downfaulted block of the mafic-intermediate batholith thought to be responsible for the Pacific Margin Anomaly. The trends of both fracture zones and magnetic lineaments strongly support the link between faulting in the Antarctic Peninsula magmatic arc and offshore tectonics. 20 refs., 3 figs.

  19. Curie point depth from spectral analysis of aeromagnetic data from Cerro Prieto geothermal area, Baja California, México

    NASA Astrophysics Data System (ADS)

    Espinosa-Cardeña, J. M.; Campos-Enriquez, J. O.

    2008-10-01

    Using aeromagnetic data acquired in the area from the Cerro Prieto geothermal field, we estimated the depth to the Curie point isotherm, interpreted as the base of the magnetic sources, following statistical spectral-based techniques. According to our results the Curie point isotherm is located at a depths ranging from 14 to 17 km. Our result is somewhat deeper than that obtained previously based only in 2-D and 3-D forward modeling of previous low-quality data. However, our results are supported by independent information comprising geothermal gradients, seismicity distribution in the crust, and gravity determined crustal thickness. Our results imply a high thermal gradient (ranging between 33 and 38 °C/km) and high heat flow (of about 100 mW/m 2) for the study area. The thermal regime for the area is inferred to be similar to that from the Salton trough.

  20. Integration of high-resolution seismic and aeromagnetic data for earthquake hazards evaluations: An example from the Willamette Valley, Oregon

    USGS Publications Warehouse

    Liberty, L.M.; Trehu, A.M.; Blakely, R.J.; Dougherty, M.E.

    1999-01-01

    Aeromagnetic and high-resolution seismic reflection data were integrated to place constraints on the history of seismic activity and to determine the continuity of the possibly active, yet largely concealed Mount Angel fault in the Willamette Valley, Oregon. Recent seismic activity possibly related to the 20-km-long fault includes a swarm of small earthquakes near Woodburn in 1990 and the magnitude 5.6 Scotts Mills earthquake in 1993. Newly acquired aeromagnetic data show several large northwest-trending anomalies, including one associated with the Mount Angel fault. The magnetic signature indicates that the fault may actually extend 70 km across the Willamette Valley to join the Newberg and Gales Creek faults in the Oregon Coast Range. We collected 24-fold high-resolution seismic reflection data along two transects near Woodburn, Oregon, to image the offset of the Miocene-age Columbia River Basalts (CRB) and overlying sediments at and northwest of the known mapped extent of the Mount Angel fault. The seismic data show a 100-200-m offset in the CRB reflector at depths from 300 to 700 m. Folded or offset sediments appear above the CRB with decreasing amplitude to depths as shallow as were imaged (approximately 40 m). Modeling experiments based on the magnetic data indicate, however, that the anomaly associated with the Mount Angel fault is not caused solely by an offset of the CRB and overlying sediments. Underlying magnetic sources, which we presume to be volcanic rocks of the Siletz terrane, must have vertical offsets of at least 500 m to fit the observed data. We conclude that the Mount Angel fault appears to have been active since Eocene age and that the Gales Creek, Newberg, and Mount Angel faults should be considered a single potentially active fault system. This fault, as well as other parallel northwest-trending faults in the Willamette Valley, should be considered as risks for future potentially damaging earthquakes.

  1. Structural study of Wamba and Environs, north-central Nigeria using aeromagnetic data and NigeriaSat-X image

    NASA Astrophysics Data System (ADS)

    Ogunmola, J. K.; Gajere, E. N.; Ayolabi, E. A.; Olobaniyi, S. B.; Jeb, D. N.; Agene, I. J.

    2015-11-01

    Wamba 1:100,000 sheet 210 covers Wamba and Nassarawa Eggon area of North-Central Nigeria and consists of basement rocks, biotite granites and Older Granites in most parts of the northern part and by sedimentary rocks of the Cretaceous Middle Benue Trough in the southern part. High resolution aeromagnetic data was interpreted and the results integrated in a GIS environment with data from NigeriaSat-X image to map out the major structural trends within the area. Reduction-to-the-equator (RTE) operation was carried out on the aeromagnetic data after which several data transforms/derivatives such as horizontal derivative, analytical signal, and tilt derivative were calculated to highlight subsurface boundaries and the major structures within the area. Several digital image enhancement techniques such as general contrast stretching and edge enhancement were applied to the NigeraSat-X image in ERDAS IMAGINE 9.2 after which structures from the interpreted magnetic data and the image were mapped out on-screen using ArcMap 10. The results show that the RTE produced a reasonable geological picture of the area. Also the basement configuration consists of several NE-SW and NW-SE structures that range from 1 km to about 17 km in length with the NE-SW structures being the major trend within the area. The lineaments are mainly within the basement and the Older granites and may be related to the Pan-African Orogeny. This study was also able to map out more accurately the contact between the basement and the sediments hence a modified geological map of the area was produced.

  2. Experiment K-6-13. Morphological and biochemical examination of heart tissue. Part 1: Effects of microgravity on the myocardial fine structure of rats flown on Cosmos 1887. Ultrastructure studies. Part 2: Cellular distribution of cyclic ampdependent protein kinase regulatory subunits in heart muscle of rats flown on Cosmos 1887

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Kato, K.; Stevenson, J.; Miquel, Jaime; Mednieks, M. I.; Sapp, W.; Popova, I. A.; Serova, L. V.

    1990-01-01

    The left ventricle of hearts from rats flown on the Cosmos 1887 biosatellite for 12.5 days was compared to the same tissue of synchronous and vivarium control animals maintained in a ground based laboratory. The volume density of the mitochondria in the myocardium of the space-flown animals was statistically less (p equal less than 0.01) than that of the synchronous or vivarium control rats. Exposure to microgravity resulted in a certain degree of myocardial degeneration manifested in mitochondrial changes and accumulation of myeloid bodies. Generalized myofibrillar edema was also observed.

  3. Changes in miRNA expression profile of space-flown Caenorhabditis elegans during Shenzhou-8 mission

    NASA Astrophysics Data System (ADS)

    Xu, Dan; Gao, Ying; Huang, Lei; Sun, Yeqing

    2014-04-01

    Recent advances in the field of molecular biology have demonstrated that small non-coding microRNAs (miRNAs) have a broad effect on gene expression networks and play a key role in biological responses to environmental stressors. However, little is known about how space radiation exposure and altered gravity affect miRNA expression. The "International Space Biological Experiments" project was carried out in November 2011 by an international collaboration between China and Germany during the Shenzhou-8 (SZ-8) mission. To study the effects of spaceflight on Caenorhabditis elegans (C. elegans), we explored the expression profile miRNA changes in space-flown C. elegans. Dauer C. elegans larvae were taken by SZ-8 spacecraft and experienced the 16.5-day shuttle spaceflight. We performed miRNA microarray analysis, and the results showed that 23 miRNAs were altered in a complex space environment and different expression patterns were observed in the space synthetic and radiation environments. Most putative target genes of the altered miRNAs in the space synthetic environment were predicted to be involved in developmental processes instead of in the regulation of transcription, and the enrichment of these genes was due to space radiation. Furthermore, integration analysis of the miRNA and mRNA expression profiles confirmed that twelve genes were differently regulated by seven miRNAs. These genes may be involved in embryonic development, reproduction, transcription factor activity, oviposition in a space synthetic environment, positive regulation of growth and body morphogenesis in a space radiation environment. Specifically, we found that cel-miR-52, -55, and -56 of the miR-51 family were sensitive to space environmental stressors and could regulate biological behavioural responses and neprilysin activity through the different isoforms of T01C4.1 and F18A12.8. These findings suggest that C. elegans responded to spaceflight by altering the expression of miRNAs and some target

  4. Changes in miRNA expression profile of space-flown Caenorhabditis elegans during Shenzhou-8 mission.

    PubMed

    Xu, Dan; Gao, Ying; Huang, Lei; Sun, Yeqing

    2014-04-01

    Recent advances in the field of molecular biology have demonstrated that small non-coding microRNAs (miRNAs) have a broad effect on gene expression networks and play a key role in biological responses to environmental stressors. However, little is known about how space radiation exposure and altered gravity affect miRNA expression. The "International Space Biological Experiments" project was carried out in November 2011 by an international collaboration between China and Germany during the Shenzhou-8 (SZ-8) mission. To study the effects of spaceflight on Caenorhabditis elegans (C. elegans), we explored the expression profile miRNA changes in space-flown C. elegans. Dauer C. elegans larvae were taken by SZ-8 spacecraft and experienced the 16.5-day shuttle spaceflight. We performed miRNA microarray analysis, and the results showed that 23 miRNAs were altered in a complex space environment and different expression patterns were observed in the space synthetic and radiation environments. Most putative target genes of the altered miRNAs in the space synthetic environment were predicted to be involved in developmental processes instead of in the regulation of transcription, and the enrichment of these genes was due to space radiation. Furthermore, integration analysis of the miRNA and mRNA expression profiles confirmed that twelve genes were differently regulated by seven miRNAs. These genes may be involved in embryonic development, reproduction, transcription factor activity, oviposition in a space synthetic environment, positive regulation of growth and body morphogenesis in a space radiation environment. Specifically, we found that cel-miR-52, -55, and -56 of the miR-51 family were sensitive to space environmental stressors and could regulate biological behavioural responses and neprilysin activity through the different isoforms of T01C4.1 and F18A12.8. These findings suggest that C. elegans responded to spaceflight by altering the expression of miRNAs and some target

  5. Dorsal raphe nucleus of brain in the rats flown in space inflight and postflight alteration of structure

    NASA Astrophysics Data System (ADS)

    Krasnov, I.

    The structure of brain dorsal raphe nucleus (DRN) was studied in the rats flown in space aboard Space Shuttle "Columbia" (STS-58, SLS-2 program) and dissected on day 13 of the mission ("inflight" rats) and in 5-6 hours after finishing 14-day flight ("postflight" rats). The brain of "inflight" rats were excised after decapitation, sectioned sagitally halves of brain were fixed by immersion in 2,5 % glutaraldehyde in 0.1 M cacodylate buffer pH 7.3 at 4°C and kept in the flight at 4°C. After landing the brain frontal 0.5 mm sections from DRN area were osmificated and embedded in araldite at NASA ARC. The brains of "postflight": and control rats were underwent to the same procedure. Electronmicroscopical analysis, computer morphometry and glial cell count were performed at Moscow. In DRN neuropil of "inflight" rats the most part of axo-dendritic synapses were surrounded by glia cell processes and had decreased electron density of pre- and postsynaptic membrane and pronounced diminution of synaptic vesicle amount while dendrites were characterized by decrease in matrix electron density and microtubule quantity that in total indicates the decline of afferent flow reaching DRN neurons in microgravity. In DRN neurons of "inflight" rats all mitochondria were characterized by evenly increased dimensions, decreased matrix electron density, small amount of short and far- between located cristae and enlarged intermembrane and intercristae spaces, that in total points out low level of coupling of oxidation to phosphorilation, decrease in energy supply of neuron. Amount of ribosome in cytoplasm was significantly decreased indicating lower lever of biosynthetic processes. The last is supported by diminished dimensions of neuronal body, nucleus and nucleolus (place of r RNA synthesis), cross section area of that were reduced in DRN neurons of "inflight" rats by 18.8 % (p < 0.01), 11.1 % and 26.6 % (p <0,005) correspondingly. Ultrastructure and dimensions of intracellular

  6. Changes in miRNA expression profile of space-flown Caenorhabditis elegans during Shenzhou-8 mission.

    PubMed

    Xu, Dan; Gao, Ying; Huang, Lei; Sun, Yeqing

    2014-04-01

    Recent advances in the field of molecular biology have demonstrated that small non-coding microRNAs (miRNAs) have a broad effect on gene expression networks and play a key role in biological responses to environmental stressors. However, little is known about how space radiation exposure and altered gravity affect miRNA expression. The "International Space Biological Experiments" project was carried out in November 2011 by an international collaboration between China and Germany during the Shenzhou-8 (SZ-8) mission. To study the effects of spaceflight on Caenorhabditis elegans (C. elegans), we explored the expression profile miRNA changes in space-flown C. elegans. Dauer C. elegans larvae were taken by SZ-8 spacecraft and experienced the 16.5-day shuttle spaceflight. We performed miRNA microarray analysis, and the results showed that 23 miRNAs were altered in a complex space environment and different expression patterns were observed in the space synthetic and radiation environments. Most putative target genes of the altered miRNAs in the space synthetic environment were predicted to be involved in developmental processes instead of in the regulation of transcription, and the enrichment of these genes was due to space radiation. Furthermore, integration analysis of the miRNA and mRNA expression profiles confirmed that twelve genes were differently regulated by seven miRNAs. These genes may be involved in embryonic development, reproduction, transcription factor activity, oviposition in a space synthetic environment, positive regulation of growth and body morphogenesis in a space radiation environment. Specifically, we found that cel-miR-52, -55, and -56 of the miR-51 family were sensitive to space environmental stressors and could regulate biological behavioural responses and neprilysin activity through the different isoforms of T01C4.1 and F18A12.8. These findings suggest that C. elegans responded to spaceflight by altering the expression of miRNAs and some target

  7. The effect of exposure to microgravity on the development and structural organisation of plant protoplasts flown on Biokosmos 9.

    PubMed

    Rasmussen, O; Klimchuk, D A; Kordyum, E L; Danevich, L A; Tarnavskaya, E B; Lozovaya, V V; Tairbekov, M G; Baggerud, C; Iversen, T H

    1992-01-01

    Preparatory experiments for the IML-1 (International Microgravity Laboratory) mission to be flown on the Space Shuttle in January, 1992, were performed on a 14 day flight on Biokosmos 9 (Kosmos 2044) in September 1989. The purpose of the experiment was to study the effect of weightlessness on protoplast regeneration. Problems with late access to the space vehicle meant that the newly isolated protoplasts from hypocotyl cells of rapeseed (Brassica napus L. cv Niklas) and suspension cultures of carrot (Daucus carota L, cv Nobo) had to be stored at 4 degrees C for 36 h prior to the launch of the biosatellite, in order to delay cell wall regeneration until the samples were in orbit. In the flight samples and the ground controls, a portion of the total number of protoplasts regenerated cell walls. The growth of flight rapeseed cells was only 56% compared to the ground control; the respective growth of carrot cells in orbit was 82% of the ground control. Analysis demonstrated that the peroxidase activity and the amount of protein was lower in the flight samples than in the ground controls. The number of different isoenzymes was also decreased in the flight samples. A 54% decrease in the production of cellulose was found in rapeseed, and a 71% decrease in carrot. Hemicellulose production was also decreased in the flight samples compared to the ground controls. Ultrastructural analysis of the cell aggregates from the protoplasts cultured in orbit, demonstrated that hydrolysis and disappearance of reserve starch occurred in the flight cell plastids. The mitochondria were more varied in appearance in the flight samples than in the ground control cells. An increased frequency of the occurrence of folds formed by the plasmalemma together with an increase in the degree of complexity of these folds was also observed. Fluorescence analysis showed a decrease of the calcium content in cell cultures under space flight compared to the ground controls. One general effect of the stay

  8. The effect of exposure to microgravity on the development and structural organisation of plant protoplasts flown on Biokosmos 9.

    PubMed

    Rasmussen, O; Klimchuk, D A; Kordyum, E L; Danevich, L A; Tarnavskaya, E B; Lozovaya, V V; Tairbekov, M G; Baggerud, C; Iversen, T H

    1992-01-01

    Preparatory experiments for the IML-1 (International Microgravity Laboratory) mission to be flown on the Space Shuttle in January, 1992, were performed on a 14 day flight on Biokosmos 9 (Kosmos 2044) in September 1989. The purpose of the experiment was to study the effect of weightlessness on protoplast regeneration. Problems with late access to the space vehicle meant that the newly isolated protoplasts from hypocotyl cells of rapeseed (Brassica napus L. cv Niklas) and suspension cultures of carrot (Daucus carota L, cv Nobo) had to be stored at 4 degrees C for 36 h prior to the launch of the biosatellite, in order to delay cell wall regeneration until the samples were in orbit. In the flight samples and the ground controls, a portion of the total number of protoplasts regenerated cell walls. The growth of flight rapeseed cells was only 56% compared to the ground control; the respective growth of carrot cells in orbit was 82% of the ground control. Analysis demonstrated that the peroxidase activity and the amount of protein was lower in the flight samples than in the ground controls. The number of different isoenzymes was also decreased in the flight samples. A 54% decrease in the production of cellulose was found in rapeseed, and a 71% decrease in carrot. Hemicellulose production was also decreased in the flight samples compared to the ground controls. Ultrastructural analysis of the cell aggregates from the protoplasts cultured in orbit, demonstrated that hydrolysis and disappearance of reserve starch occurred in the flight cell plastids. The mitochondria were more varied in appearance in the flight samples than in the ground control cells. An increased frequency of the occurrence of folds formed by the plasmalemma together with an increase in the degree of complexity of these folds was also observed. Fluorescence analysis showed a decrease of the calcium content in cell cultures under space flight compared to the ground controls. One general effect of the stay

  9. Optical contamination: its prevention in the XUV spectrographs flown by the U.S. Naval Research Laboratory in the Apollo Telescope Mount.

    PubMed

    Hunter, W R

    1977-04-01

    During construction and testing of the XUV spectrographs flown in the ATM by the Naval Research Laboratory, many problems associated with optical contamination were encountered. Solving these problems required setting up a contamination prevention program to select the materials used in constructing the instruments and to delineate procedures in assembling, testing, and storing the instruments. A brief description is given of methods of assessing the effects of contamination and of the procedures used to prevent contamination. PMID:20168611

  10. National Uranium Resource Evaluation stream-sediment, hydrogeochemical, and aeromagnetic data characteristics of the Piedmont Region, eastern United States: a data release

    SciTech Connect

    Madson, M.E.; Rush, S.F.; Hardy, L.C.; LaBonte, N.E.; Ludlam, J.R.

    1983-11-01

    Characteristics of National Uranium Resource Evaluation (NURE) stream-sediment, hydrogeochemical, and aeromagnetic data for sixteen contiguous 1/sup 0/ x 2/sup 0/ National Topographic Map Series (NTMS) quadrangles in the eastern United States are presented in this report. The work is limited in scope to features of specific interest to the geoscience community, even though NURE data may implicitly relate to such other fields as agriculture and land-use planning. The data used to produce the residual aeromagnetic and geochemical maps in this report have been previously open-filed. The tectonic map and the igneous rock distribution map were compiled from published, larger scale maps. When used together, these maps show geochemical, tectonic, and magnetic features unique to many of the geologic and physiographic provinces in the region.

  11. Missouri aeromagnetic and gravity maps and data: a web site for distribution of data

    USGS Publications Warehouse

    Kucks, Robert P.; Hill, Patricia L.

    2005-01-01

    Magnetic anomalies are due to variations in the Earth's magnetic field caused by the uneven distribution of magnetic minerals (primarily magnetite) in the rocks that make up the upper part of the Earth's crust. The features and patterns of the magnetic anomalies can be used to delineate details of subsurface geology, including the locations of buried faults and magnetite-bearing rocks and the depth to the base of sedimentary basins. This information is valuable for mineral exploration, geologic mapping, and environmental studies. The Missouri magnetic map is constructed from grids that combine information collected in 25 separate magnetic surveys conducted between 1943 and 1987. The data from these surveys are of varying quality. The design and specifications (terrain clearance, sampling rates, line spacing, and reduction procedures) varied from survey to survey depending on the purpose of the project and the technology of that time. Every attempt was made to acquire the data in digital form.

  12. Three-Dimensional Mapping of Magnetic Strata From Aeromagnetic Anomalies: The Deformed Neroly Formation South of Mt. Diablo, Northern California

    NASA Astrophysics Data System (ADS)

    Jachens, R. C.; Simpson, R. W.; Graymer, R. W.; Wentworth, C. M.

    2008-12-01

    We apply direct inversion of aeromagnetic anomalies to analyze the subsurface 3D shape of the highly magnetic Miocene Neroly Formation, which consists largely of medium to coarse-grained andesitic sandstones containing abundant magnetite. The Neroly Formation is widespread in the eastern San Francisco Bay region, and locally is tightly folded and disrupted by faulting in the compressional regime related to the left-stepping (restraining) connection between the strike-slip Greenville and Concord Faults. The inversion technique is based on the conversion of the anomalies produced by a magnetic layer to their equivalent magnetic potential (psuedogravity) anomalies, manipulation of these anomalies to produce anomalies that would result from a half-space with a variable-depth top having the shape of the top surface of the layer, and then inverting these pseudogravity anomalies for the shape of that top surface. Assumptions include a constant layer thickness, uniform magnetization which implies a constant pseudodensity contrast, and a surface that is single-valued (no recumbent folds or strata repeated with depth). Constraints on 3D position are applied where the layer crops out or is at a depth known from well or other information. Application of this inversion technique to aeromagnetic anomalies over the Neroly Formation yields a complex top surface characterized by elongate overlapping troughs and structural highs, including the well-known Tassajara anticline and adjacent Sycamore Valley syncline. Troughs are true synclinal lows whereas the structural highs may be fold crests, steep truncated strata, and/or fault duplicated strata. The strongest deformation is confined to within ~7 km of the near-vertical overturned Neroly beds that crop out along the NE margin of the valley, and is characterized by four laterally overlapping, margin parallel structural highs and intervening troughs, each between 10 and 20 km in length. A fifth possible structural high lies farther SW

  13. Aeromagnetic legacy for a diffuse intraplate boundary between northern Victoria Land and the Wilkes Subglacial Basin (East Antarctica)

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.; Armadillo, E.; Bozzo, E.

    2012-04-01

    Major terrane bounding faults and intra-terrane faults that were active during early Paleozoic subduction and accretion stages of the Ross Orogen have been subject to intense research over the northern Victoria Land sector of East Antarctica. However, the paucity of outcrop, coupled with incomplete geophysical data coverage, has limited the ability to trace the inland extent and architecture of these basement fault systems and has hampered efforts to assess their controls on later Cenozoic intraplate faulting within the Transantarctic Mountains and the eastern margin of the Wilkes Subglacial Basin. Here we compile and analyse new enhanced aeromagnetic anomaly images that help constrain regional-scale crustal architecture and tectonic evolution over northern Victoria Land and the eastern margin of the Wilkes Subglacial Basin. Long-wavelength magnetic lows are modelled as reflecting several-km thick sedimentary basins of inferred early Cambrian age that were inverted along major thrust faults during the late stages of the Ross Orogen to form a major pop-up structure within the Wilson Terrane. A residual Bouguer gravity high in the central Wilson Terrane corresponds to a broad magnetic low and images the ~500 Ma old high-grade granulite-facies core of the pop-up. Arrays of NNW trending magnetic lineaments reveal thin sheared sheets of mylonitic granitoids emplaced along the late Ross (~480 Ma old) Exiles Thrust fault system within the western Wilson Terrane, which is also marked by a prominent deep electrical conductivity anomaly. In contrast, much thicker magmatic arc intrusions are modelled along the Prince Albert Fault System that fringes the eastern margin of the Wilkes Subglacial Basin. Recent zircon U-Pb dating over exposures of gabbro-diorites within the Prince Albert Mountains further south suggest that these intrusions may have been emplaced during an earlier stage of subduction (~520 Ma or older?), likely in a transtensional setting. Our magnetic models

  14. Aeromag interpretation technology helps chase Cambrian in New York

    SciTech Connect

    Fagan, J.P. Jr.; Copley, D.L.

    1998-02-16

    Building a geologic model from the bottom up, Ardent Resources Inc. conducted a high-sensitivity, high-resolution aeromagnetic survey in western New York. The aeromagnetic survey was flown to delineate deep-seated structural patterns which affected emplacement of Cambrian oil and gas reservoirs. In an effort to extend the Rose Run play into western New York, Ardent employed Pearson, deRidder and Johnson Inc. (PRJ) to acquire, process, and interpret an aeromagnetic survey covering about 170,000 acres. An exploratory well drilled upon the interpretation results of the survey is an indicated gas discovery in the Rose run equivalent upper Cambrian Theresa formation. The paper describes the geologic rationale, an integrated study, and future developments.

  15. Gravity Survey of the Rye Patch KGRA, Rye Patch, Nevada

    NASA Astrophysics Data System (ADS)

    Mcdonald, M. R.; Gosnold, W. D.

    2011-12-01

    The Rye Patch Known Geothermal Resource Area (KGRA) is located in Pershing County Nevada on the west side of the Humboldt Range and east of the Rye Patch Reservoir approximately 200 km northeast of Reno, Nevada. Previous studies include an earlier gravity survey, 3-D seismic reflection, vertical seismic profiling (VSP) on a single well, 3-D seismic imaging, and a report of the integrated seismic studies. Recently, Presco Energy conducted an aeromagnetic survey and is currently in the process of applying 2-D VSP methods to target exploration and production wells at the site. These studies have indicated that geothermal fluid flow primarily occurs along faults and fractures and that two potential aquifers include a sandstone/siltstone member of the Triassic Natchez Pass Formation and a karst zone that occurs at the interface between Mesozoic limestone and Tertiary volcanics. We hypothesized that addition of a high-resolution gravity survey would better define the locations, trends, lengths, and dip angles of faults and possible solution cavity features. The gravity survey encompassed an area of approximately 78 km2 (30 mi2) within the boundary of the KGRA along with portions of 8 sections directly to the west and 8 sections directly to the east. The survey included 203 stations that were spaced at 400 m intervals. The simple Bouguer anomaly patterns were coincident with elevation, and those patterns remained after terrain corrections were performed. To remove this signal, the data were further processed using wave-length (bandpass) filtering techniques. The results of the filtering and comparison with the recent aeromagnetic survey indicate that the location and trend of major fault systems can be identified using this technique. Dip angles can be inferred by the anomaly contour gradients. By further reductions in the bandpass window, other features such as possible karst solution channels may also be recognizable. Drilling or other geophysical methods such as a

  16. Optimizing the use of aeromagnetic data for predictive geological interpretation: an example from the Grenville Province, Quebec

    NASA Astrophysics Data System (ADS)

    Parsons, Sharon; Nadeau, Léopold; Keating, Pierre; Chung, Chang-Jo

    2006-06-01

    Predictive geological mapping relies largely on the empirical and statistical analysis of aeromagnetic data. However, in most applications the analysis remains essentially visual and unconstrained. The lithological and structural diversity of rock units underlying the Mingan Region make it an ideal test area to apply more rigorous approaches to magnetic data processing and interpretation, and to assess their usefulness and limitations. In the application discussed here, various derivatives and transformations of the total field magnetic data are evaluated empirically by photo-interpretation using a Geographic Information System. We show that rock types are best represented using the total field and vertical derivative of the magnetic data, whereas contacts between rock types are best delineated using the horizontal derivative of the total field and the analytic signal. In addition, the maxima of the analytic signal are used to estimate the direction of dip of large-scale geological units. Statistical analyses show that the correlation between geology and magnetic data is not directly proportional. Finally, the source of discrepancies between mapped geological units and magnetic response are evaluated through theoretical data modeling of representative geological bodies.

  17. Experiment K-7-18: Effects of Spaceflight in the Muscle Adductor Longus of Rats Flown in the Soviet Biosatellite Cosmos 2044. Part 2; Quantitative Autoradiographic Analysis of Gaba (Benzodiazepine) and Muscarinic (Cholinergic) Receptors in the Forebrain of Rats Flown on Cosmos 2044

    NASA Technical Reports Server (NTRS)

    Wu, L.; Daunton, N. G.; Krasnov, I. B.; DAmelio, F.; Hyde, T. M.; Sigworth, S. K.

    1994-01-01

    Quantitative autoradiographic analysis of receptors for GABA and acetylcholine in the forebrain of rats flown on COSMOS 2044 was undertaken as part of a joint US-Soviet study to determine the effects of microgravity on the central nervous system, and in particular on the sensory and motor portions of the forebrain. Changes in binding of these receptors in tissue from animals exposed to microgravity would provide evidence for possible changes in neural processing as a result of exposure to microgravity. Tritium-labelled diazepam and Quinuclidinyl-benzilate (QNB) were used to visualize GABA (benzodiazepine) and muscarinic (cholinergic) receptors, respectively. The density of tritium-labelled radioligands bound to various regions in the forebrain of both flight and control animals were measured from autoradiograms. Data from rats flown in space and from ground-based control animals that were not exposed to microgravity were compared.

  18. Geological analysis of aeromagnetic data from southwestern Alaska: implications for exploration in the area of the Pebble porphyry Cu-Au-Mo deposit

    USGS Publications Warehouse

    Anderson, Eric D.; Hitzman, Murray W.; Monecke, Thomas; Bedrosian, Paul A.; Shah, Anjana K.; Kelley, Karen D.

    2013-01-01

    Aeromagnetic data are used to better understand the geology and mineral resources near the Late Cretaceous Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The reduced-to-pole (RTP) transformation of regional-scale aeromagnetic data shows that the Pebble deposit is within a cluster of magnetic anomaly highs. Similar to Pebble, the Iliamna, Kijik, and Neacola porphyry copper occurrences are in magnetic highs that trend northeast along the crustal-scale Lake Clark fault. A high-amplitude, short- to moderate-wavelength anomaly is centered over the Kemuk occurrence, an Alaska-type ultramafic complex. Similar anomalies are found west and north of Kemuk. A moderate-amplitude, moderate-wavelength magnetic low surrounded by a moderate-amplitude, short-wavelength magnetic high is associated with the gold-bearing Shotgun intrusive complex. The RTP transformation of the district-scale aeromagnetic data acquired over Pebble permits differentiation of a variety of Jurassic to Tertiary magmatic rock suites. Jurassic-Cretaceous basalt and gabbro units and Late Cretaceous biotite pyroxenite and granodiorite rocks produce magnetic highs. Tertiary basalt units also produce magnetic highs, but appear to be volumetrically minor. Eocene monzonite units have associated magnetic lows. The RTP data do not suggest a magnetite-rich hydrothermal system at the Pebble deposit. The 10-km upward continuation transformation of the regional-scale data shows a linear northeast trend of magnetic anomaly highs. These anomalies are spatially correlated with Late Cretaceous igneous rocks and in the Pebble district are centered over the granodiorite rocks genetically related to porphyry copper systems. The spacing of these anomalies is similar to patterns shown by the numerous porphyry copper deposits in northern Chile. These anomalies are interpreted to reflect a Late Cretaceous magmatic arc that is favorable for additional discoveries of Late Cretaceous porphyry copper systems in southwestern

  19. Dextral Shear on the Olympic-Wallowa Lineament, Washington--Evidence from High-Resolution Aeromagnetic Anomalies and Implications for Cascadia Seismic Hazards

    NASA Astrophysics Data System (ADS)

    Blakely, R. J.; Sherrod, B. L.; Weaver, C. S.; Wells, R. E.

    2013-12-01

    The Olympic-Wallowa physiographic lineament (OWL) extends northwestward ~500 km from northeastern Oregon to Vancouver Island, British Columbia. The tectonic relevance of the OWL, particularly the degree to which horizontal shear has contributed to its evolution, is an important element in assessing kinematic connections between the Cascadia backarc and forearc, and the consequent seismic hazard it poses to the region. Past workers have come to rather different conclusions, some suggesting sinistral, others suggesting dextral, and still others suggesting no horizontal displacement on the OWL. North-northwest-striking dikes of the 8.5 Ma Ice Harbor Member of the Columbia River Basalt Group are offset and disrupted by the Wallula fault zone (WFZ), a 45-km-long segment of the OWL southeast of Kennewick. Although mostly concealed by young deposits, Ice Harbor dikes are clearly delineated in high-resolution aeromagnetic anomalies as near-vertical intrusions, affording an opportunity to estimate the sense and amount of offset along this part of the OWL. Aided by various derivative products calculated from magnetic anomalies, we interpret five piercing points from single-dike anomalies intersecting the Wallula fault (the northernmost strand of the WFZ), together indicating an average of 1.72 km of right-lateral offset on this single strand. Right-lateral offset across the entire WFZ is 6.9 km, an average rate of 0.8 mm/y since 8.5 Ma. We cannot rule out the possibility that tectonic offsets are only apparent because the injection process itself was offset during emplacement. However, consistent right-lateral offsets are observed in stream drainages along the OWL, supporting our magnetic anomaly interpretations. Aerial photography and airborne LiDAR surveys show seven offset streams along a fault scarp on the northeastern slope of Rattlesnake Mountain, located along the OWL about 70 km northwest of the WFZ. Incised in Pleistocene deposits, these stream offsets average about

  20. Aeromagnetic and gravity investigations of the Coastal Area and Continental Shelf of Liberia, West Africa, and their relation to continental drift

    USGS Publications Warehouse

    Behrendt, John C.; Wotorson, Cletus S.

    1970-01-01

    An aeromagnetic survey has shown the existence of several basins in which magnetic basement depths are greater than 5 km on the continental shelf off Liberia. Magnetic diabase of 176 to 192 m.y. (Jurassic) in age intruding the Paleozoic (?) rocks and overlain by younger rocks onshore requires the distinction between “magnetic basement” and “basement.” Several lines of evidence suggest that the Paleozoic(?) rocks are less than 1 km thick; this implies that the diabase does not introduce a large error in depth-to-basement estimates. The dikes or their extrusive equivalents are traceable, on the basis of the magnetic data, beneath the younger sedimentary rock in the basins to the edge of the continental slope. The magnetic data also delineate a second zone of diabase dikes 90 km inland, parallel to the coast, which cross the entire country. The intrusion of the younger dikes probably coincides with rifting at the beginning of the separation of Africa and South America, and the associated magnetic anomaly zones appear to be parallel with and continuous into the anomaly bands in the Atlantic. A major northeast-trending break in the magnetic fabric intersects the coast near 9° W. and is associated with Eburnean age rocks (about 2000 m.y.) to the southeast as contrasted with Liberian-age rocks (about 2700 m.y.) to the northwest. Change in magnetic fabric direction inland from northeast to northwest in the coastal area allows recognition of a boundary between the Liberian-age rocks inland and Pan-African-age (about 550 m.y.) rocks in the coastal area northwest of about 9° 20'W. Sets of north-northwest-and west-northwest—trending faults of 1 to 2 km vertical displacement cut the Cretaceous sedimentary rocks onshore and can be traced into the offshore basins. Vertical displacements of several kilometers in the magnetic basement underlying the continental shelf suggest a pattern of block faulting all along the coast and continental shelf. Negative Bouguer

  1. Aeromagnetic data, processing, and maps of Fort Irwin and vicinity, California: Chapter I in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

    USGS Publications Warehouse

    Langenheim, V.E.; Jachens, Robert C.; Buesch, David C.

    2014-01-01

    Aeromagnetic data help provide the underpinnings of a hydrogeologic framework for Fort Irwin by locating inferred structural features or grain that influence groundwater flow. Magnetization boundaries defined by horizontal-gradient analyses coincide locally with Cenozoic faults and can be used to extend these faults beneath cover. These boundaries also highlight the structural grain within the crystalline rocks and may serve as a proxy for fracturing, an important source of permeability within the generally impermeable basement rocks, thus mapping potential groundwater pathways through and along the mountain ranges in the study area.

  2. Geophysical investigations on the gravity and aeromagnetic anomalies of the region between Sapanca and Duzce, along the North Anatolian Fault, Turkey

    NASA Astrophysics Data System (ADS)

    Tigli, Cigdem Sendur; Ates, Abdullah; Aydemir, Attila

    2012-12-01

    In this paper, it is aimed to model subsurface structures to the east of the Gulf of Izmit through Duzce by using the gravity and aeromagnetic anomaly data. 1/500.000 scaled gravity anomaly map of the area was taken from the General Directorate of Mineral Research and Exploration (MTA) and it was digitized. The aeromagnetic anomaly data were obtained in the digital form. 3D and 2D models were constructed to reveal the subsurface structure in two different inset regions in the study area including most important negative and positive gravity anomalies. Seismic velocities obtained from the deep seismic recordings were converted to densities. In addition, density information from a previous research was also taken. These densities were used for construction of 3D and 2D gravity models where it was shown that there are narrow and long sedimentary basins and depressions with 0.5-3 km depths. These sedimentary basins with the shape of negative flower structures indicating pull-apart basins are controlled by the active fault segments of the North Anatolian Fault (NAF). Earthquake epicenter data were also correlated with the constructed models from the gravity anomalies. Positive gravity anomalies are also caused by very shallow (about 2 km) masses that are accepted as the crustal origin intrusions into the fractures of the NAF and, ophiolites and gabbro outcropping on the surface of the studied regions. These intrusives and remnants of the Tethys Ocean are located between the fault segments where the fault bifurcates and they also constitute barriers for straight extension of the NAF. Analytic signal method was applied to the aeromagnetic anomaly data to determine the locations and boundaries of the causative bodies. Those bodies are observed around Duzce, and to the E-SE of it, to the NW of Golyaka and a large mass between Adapazari and Sapanca. Shallow settlement of these magmatics was confirmed by the second vertical derivative of the aeromagnetic data. An anti

  3. Structural geology and regional tectonics of the Mineral County area, Nevada, using Shuttle Imaging Radar-B and digital aeromagnetic data

    NASA Technical Reports Server (NTRS)

    Borengasser, Marcus X.; Taranik, James V.

    1988-01-01

    SIR-B and aeromagnetic lineaments show a correlation with known faults within the Walker Lane of the western Basin and Range Province. Walker Lane faults can be extended based on SIR-B data and unmapped Walker Lane features are identified. South of the Pancake Range lineament, Walker Lane faults are seldom recognized but SIR-B data have the potential for delineating structural features in this area. Earthquake hypocenter distribution in profiles across a SIR-B lineament is consistent with that expected from a vertical fault. Field examination indicates that the lineament is an unmapped neotectonic Walker Lane feature.

  4. Mapping of a buried basement combining aeromagnetic, gravity and petrophysical data: The substratum of southwest Paris Basin, France

    NASA Astrophysics Data System (ADS)

    Baptiste, Julien; Martelet, Guillaume; Faure, Michel; Beccaletto, Laurent; Reninger, Pierre-Alexandre; Perrin, José; Chen, Yan

    2016-06-01

    Aeromagnetic and gravity data have proven to be among the most effective methods for mapping deeply buried basin/basement interfaces. However, the data interpretation generally suffers from ambiguities, due to the non-uniqueness of the gravity and magnetic signatures. Here, we tie the gravity and magnetic signatures with a petrophysical characterization of the lithologies outcropping around the French Paris Basin. Our methodology investigates the lithology and structure of its hidden Variscan substratum at the junction between the Armorican Massif and Massif Central. Our approach is based on the combination of potential field data, magnetic susceptibilities measured in the field, density values of sample rocks and information documented in boreholes, in order to propose a new interpretative geological map of the buried substratum of the Paris Basin. The petrophysical description is combined with geophysical patterns of the substratum, mapped through statistical unsupervised classification of suitably selected magnetic and gravity maps. The first step of interpretation consists in extending the outcropping major structures below the Meso-Cenozoic sedimentary cover of the Paris Basin. The litho-structural units, in between these major structures, are then interpreted separately. The second step consists in assigning lithologies within each unit, with respect to its magnetization and density (as derived from the petrophysical compilation), and mapping its extension under cover, integrating punctual borehole information. Overall, with a special emphasis on relating geophysical signatures and petrophysical characteristics of litho-structural units, this methodology permits a precise structural and lithological cartography of a segment of the buried Variscan substratum. In the southwestern part of the Paris Basin, this approach reveals: i) the limited eastward extension of Central Brittany, ii) the eastward extension of the major Cholet fault, iii) the emphasis on N150E

  5. Reinterpretation of Paleoproterozoic accretionary boundaries of the north-central United States based on a new aeromagnetic-geologic compilation

    USGS Publications Warehouse

    Holm, D.K.; Anderson, R.; Boerboom, Terrence; Cannon, W.F.; Chandler, V.; Jirsa, M.; Miller, J.; Schneider, D.A.; Schulz, K.J.; Van Schmus, W. R.

    2007-01-01

    The Paleoproterozoic crust in the north-central U.S. represents intact juvenile terranes accreted to the rifted Archean Superior craton. A new tectonic province map, based on the interpretation of a new aeromagnetic compilation, published geologic maps, and recent geochronologic data, shows progressive accretion of juvenile arc terranes from ca. 1900-1600 Ma. Contrary to earlier models, geon 18 Penokean-interval crust is primarily confined to a ???2100 Ma tectonic embayment of the rifted Superior craton. The newly defined Spirit Lake tectonic zone, characterized by a sharp magnetic discontinuity that marks the southern limit of Archean and Penokean-interval rocks, is here interpreted to represent an eastern analog of the Cheyenne belt suture zone in southern Wyoming. South of this boundary, geon 17 Yavapai-interval rocks form the basement upon which 1750 Ma rhyolite and succeeding quartzite sequences were deposited. Substantial portions of the Penokean and Yavapai terranes were subsequently deformed during the 1650-1630 Ma Mazatzal orogeny. The northern boundary of the Mazatzal terrane is obscured by abundant 1470-1430 Ma "anorogenic" plutons that stitched the suture with the older Yavapai terrane rocks. These data reveal a progressive tectonic younging to the south as the Laurentian craton grew southward and stabilized during the Proterozoic. Late Mesoproterozoic rift magmatism produced pronounced geophysical anomalies, indicating strong, but localized crustal modification. In comparison to the western U.S., little tectonism has occurred here in the last 1 billion years, providing a uniquely preserved record of the Precambrian evolution of the continental U.S. lithosphere. ?? 2007 Elsevier B.V. All rights reserved.

  6. Geologic significance of new isostatic gravity and aeromagnetic maps of the Winnemucca 1[degree] by 2[degree] quadrangle, Nevada

    SciTech Connect

    Oliver, H.W.; Sikora, R.F. ); Robbins, S.L. )

    1993-04-01

    Since Wagini's 1986 Bouguer and isostatic gravity compilations of the Winnemucca 1[degree] by 2[degree] quadrangle, R. Sikora has provided an 1991 update that includes 133 new stations obtained in the Sonoma Range, Boulder Valley, and the Battle Mountain areas. Since that 1991 update, 371 additional stations have been obtained by S. Robbins in the Pine and Crescent Valley areas to look for possible gravity signatures of petroleum and gold deposits. All these data have been reduced and incorporated into a new isostatic gravity map of the quadrangle. This new compilation shows that the largest residual low of 32 mGal occurs over petroleum-bearing Pine Valley, although nearly-as-large gravity lows (27--31 mGal) occur over Buena Vista, Pleasant, Reese River, and Grass Valleys. A new aeromagnetic compilation of the Winnemucca quadrangle is continued downward to 300 m above terrain and shows a number of magnetic highs associated with igneous rocks, both intrusive and extrusive. A nearly continuous north-northwest trending magnetic high of about 400 nT, known as the northern Nevada rift, cuts across the quadrangle about 10 km east of Battle Mountain and is associated at some locations with Miocene basaltic and andesitic extrusive rocks. Three Miocene epithermal gold deposits are associated with this magnetic high at Mule Canyon, Fire Creek, and Bluckhorn. A smaller but broader magnetic high of about 200 nT at 300 m above terrain is located over the Tuscarora Mountains about 15 km northwest of Carlin. The maximum horizontal gradient of the pseudogravity transformation of the total magnetic field coincides with a series of ten productive gold mines known as the Carlin trend.

  7. Post flight operation of a high peak power neodymium YAG laser aboard the G-449 payload flown on Space Shuttle Columbia mission 61-C

    NASA Technical Reports Server (NTRS)

    Muckerheide, M. C.

    1992-01-01

    The Nd Yag laser flown on board the G-449 payload completed its postflight testing successfully. There was no indication that the laser had undergone any electronic or optical component failure. A postflight video was taken immediately following the return of the payload to the laboratory. Early anticipation of vibration and temperature changes contributed to the successful operation of the laser. Photographic material resulting from post flight videotape are presented. NASA safety reviews and recommendations supplied the insights which helped contribute to the successful operation of the Nd Yag laser. The safety review data is part of the technical presentation and gives some insight into why the system survived the severe environment of temperature and vibration during the flight of Space Shuttle 61-C.

  8. Post flight operation of a high peak power neodymium YAG laser aboard the G-449 payload flown on Space Shuttle Columbia mission 61-C

    NASA Astrophysics Data System (ADS)

    Muckerheide, M. C.

    1992-10-01

    The Nd Yag laser flown on board the G-449 payload completed its postflight testing successfully. There was no indication that the laser had undergone any electronic or optical component failure. A postflight video was taken immediately following the return of the payload to the laboratory. Early anticipation of vibration and temperature changes contributed to the successful operation of the laser. Photographic material resulting from post flight videotape are presented. NASA safety reviews and recommendations supplied the insights which helped contribute to the successful operation of the Nd Yag laser. The safety review data is part of the technical presentation and gives some insight into why the system survived the severe environment of temperature and vibration during the flight of Space Shuttle 61-C.

  9. [PROFILE OF THE MARROW-DERIVED STROMAL PRECURSORS POPULATION IN C57BL/6N MICE FLOWN ON BIOSATELLITE BION-M1].

    PubMed

    Markina, E A; Bobyleva, P I; Andrianova, I V; Andreeva, E R; Buravkova, L B

    2015-01-01

    The CFU-F number, proliferative activity and spontaneous differentiation potential of stromal cells derived from the tibia marrow of C57BL/6N mice readapted to the 1-g gravity following a long-term flight on biosatellite Bion-M1 were evaluated. The CFU-F number, proliferative activity and spontaneous adipogenic and osteogenic differentiation of marrow-derived stromal cells from the space flown group were no different from the group of vivarium control. However, the proliferative activity and adhesion properties of the cells were down-regulated on day 7 of readaptation. These results suggest that space flight factors did not impact the stromal differon of the mouse marrow. The decline of stromal cells activity indicates the decompensation of their functions under 1g gravity.

  10. Tectonic evolution and hydrocarbon prospectivity of Nigerian Frontier Grabens of Dahomey Basin from interpretation of new aeromagnetic and existing seismic and geophysical data

    SciTech Connect

    Babalola, O.O.

    1988-01-01

    Three major oceanic fracture zones, interpreted from new aeromagnetic data, intersect the Dahomey basin and extend farther inland as northeast-trending faults. Aeromagnetic anomalies running northwest across the Dahomey embayment delimit two main grabens separated by a horst; the seaward end of all of these are terminated by a northeast-trending offshore trough. The northwest-southeast grabens are interpreted as being underlain by continental crust basements but the northeast-southwest graben seems to be underlain by oceanic crust. The northwest graben (the Ikorodu or Ogun River Trough) is intersected farther seaward by a northeast-trending graben (the offshore Lagos-Badagry Trough) in the shape of a southwest-facing reflection of the letter L. The smaller and shallower Ise graben (inferred by previous investigators) continues colinearly with the major northeasterly graben. The main problems in the exploration of the Nigerian portion of the Dahomey basin include lack of drilling density, especially in the poorly mapped coastal area, and difficulty of acquisition of marine data in the shallow-water area of the Gulf of Guinea cul-de-sac.

  11. Aeromagnetic and gravity imaging of subglacial geology beneath major ice streams flowing in the Weddell Sea Embayment

    NASA Astrophysics Data System (ADS)

    Ferraccioli, Fausto; King, Owen; Jordan, Tom; Ross, Neil; Bingham, Rob; Rippin, David; LeBrocq, Anne; Siegert, Martin; Smith, Andy; Hindmarsh, Richard

    2014-05-01

    Extensive airborne geophysical research has helped unveil subglacial geology beneath the West Antarctic Ice Sheet (WAIS) in particular over the Ross Sea Embayment. Three key geological controls on the onset and maintenance of fast glacial flow for the WAIS have emerged including the presence of widespread subglacial sediments deposited within deep rift basins, thinner drapes of marine sediments within the low lying topography of the West Antarctic Rift System (WARS) and high geothermal heat flux associated with Cenozoic rift-related magmatism. Here, we compile a suite of new and vintage aerogeophysical observations over the catchments of several major ice streams flowing into the Weddell Sea Embayment to examine their large-scale geological setting and assess the role of regional geological controls on subglacial topography and WAIS flow regimes. Specifically, we examine the subglacial geology beneath the catchments of the Institute and Moeller ice streams, the Rutford ice stream and the Evans ice stream using a combination of airborne radar, aeromagnetic and airborne gravity imaging. We show that the Moeller ice stream is underlain by the largest strike-slip fault system recognised so far along the tectonic boundary between East and West Antarctica. This fault system controls the location of a set of en-echelon subglacial basins that steer enhanced flow inland. We find no evidence, however, for deep sedimentary basins along this fault system, suggesting that subglacial sediments are not necessarily a geological template for the onset of fast flow. However, the newly identified Robin Subglacial Basin that underlies the fast flowing coastal region of the Institute ice stream contains 1-3 km of sedimentary infill and remarkably smooth bedrock topography. Enhanced flow in the tributaries of the Institute ice stream that cut through the Ellsworth Mountains are controlled by major basement faults likely active in Cambrian and Permian times and perhaps reactivated during

  12. Aeromagnetic mapping of the structure of Pine Canyon caldera and Chisos Mountains intrusion, Big Bend National Park, Texas

    USGS Publications Warehouse

    Drenth, B.J.; Finn, C.A.

    2007-01-01

    Analysis of aeromagnetic and gravity data reveals new details of the structure, igneous geology, and temporal evolution of the prominent, enigmatic ca.32 Ma Pine Canyon caldera and the Chisos Mountains (Big Bend National Park, Texas). The main caldera-filling Pine Canyon Rhyolite, the oldest member of the South Rim Formation, is reversely magnetized, allowing it to be used as a key marker bed for determining caldera fill thickness. Modeling of gravity and magnetic anomalies indicates that the Pine Canyon Rhyolite is probably thicker in the northeastern part of the caldera. Lineaments in the magnetic data suggest the presence of buried faults beneath the caldera that may have led to increased downdrop in the northeast versus the southwest, allowing a thicker section of caldera fill to accumulate there. The Pine Canyon caldera has been interpreted as a downsag caldera because it lacks surficial faulting, so these inferred faults are the first mapped features there that could be responsible for caldera collapse. The caldera boundary correlates well with the margins of a gravity low. General features of the caldera match well with basic models of downsag calderas, meaning that the Pine Canyon caldera may be a classic example of downsagging, of which few well-described examples exist, in terms of a geophysical signature. The source of a long-wavelength magnetic high over the Chisos Mountains is interpreted as a previously unknown broad intrusion, the long axis of which trends parallel to a major crustal boundary related to the Ouachita orogeny or an even earlier Precambrian margin. This feature represents the largest intrusion (28-34 km diameter, 1-4 km thick, 700-3000 km3 in volume) in an area where relatively small laccoliths are ubiquitous. The intrusion most likely represents a long-lived (>1 m.y.) reservoir replenished by small batches of magma of varying composition, as reflected in the variation of eruptive products from the Pine Canyon and Sierra Quemada

  13. Infrared airborne spectroradiometer survey results in the western Nevada area

    NASA Technical Reports Server (NTRS)

    Collins, W.; Chang, S. H.; Kuo, J. T.

    1982-01-01

    The Mark II airborne spectroradiometer system was flown over several geologic test sites in western Nevada. The infrared mineral absorption bands were observed and recorded for the first time using an airborne system with high spectral resolution in the 2.0 to 2.5 micron region. The data show that the hydrothermal alteration zone minerals, carbonates, and other minerals are clearly visible in the airborne survey mode. The finer spectral features that distinguish the various minerals with infrared bands are also clearly visible in the airborne survey data. Using specialized computer pattern recognition methods, it is possible to identify mineralogy and map alteration zones and lithologies by airborne spectroradiometer survey techniques.

  14. Multi-scale integrated structural and aeromagnetic analysis to guide tectonic models: An example from the eastern Musgrave Province, Central Australia

    NASA Astrophysics Data System (ADS)

    Aitken, Alan R. A.; Betts, Peter G.

    2009-10-01

    In many polydeformed Precambrian provinces, the understanding of their tectonic history is limited by insufficient exposure, which leads to difficulty in developing links between local and regional architecture, and results in poorly constrained models of their regional-scale architecture. High-resolution aeromagnetic data allows interpretation and modelling at a scale comparable to structural mapping, and by integrating these methods, these links can be developed with high confidence. As an example, we integrate structural mapping, aeromagnetic data interpretation and 3D magnetic inversions in a multi-scale structural analysis of the polydeformed eastern Musgrave Province in central Australia. Deformation during the ca. 1200 Ma Musgravian Orogeny is characterised by an originally northeast-trending structural grain defined by shear zones and tight to isoclinal folds at all scales. 3D magnetic inversion models of syn-to-post Musgravian granites indicate that this structural grain is predominantly west dipping. This architecture suggests that a northeast-oriented fold and thrust belt developed as a result of northwest-southeast compression in central Australia during the Musgravian Orogeny. The next deformation event is characterised by an array of originally east-southeast trending shear zones that truncate and offset the Musgravian structural grain with apparent dextral displacements of up to 1 km. These shear zones are commonly co-located with mafic and granitic dykes, suggesting a dilational origin, and they are interpreted to have initiated under northeast-southwest extension during the ca. 1080 Ma Giles Event. The architecture of these two Mesoproterozoic events was later extensively overprinted by two deformation events during the Pan-African aged (ca. 550 Ma) Petermann Orogeny. The first is characterised by the widespread reactivation of Mesoproterozoic structures, resulting in a network of shear zones of variable orientation, and the second is characterised

  15. Mapping Extensional Structures in the Makgadikgadi Pans, Botswana with remote sensing and aeromagnetic data: Implication for the continuation of the East African Rift System in southern Africa

    NASA Astrophysics Data System (ADS)

    Fetkovich, E. J.; Atekwana, E. A.; Abdelsalam, M. G.; Atekwana, E. A.; Katumwehe, A. B.

    2015-12-01

    We used Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) and aeromagnetic data to map extensional structures in the Makgadikgadi Pans in northeastern Botswana. These pans are a major morphological feature in Southern Africa characterized by the presence of low lying and flat topography with the highest elevation of 945 m. This topography was a result of multiple filling and desiccation of paleo-lakes that accompanied alternation of wetter and dryer climate during the Late Quaternary period. The objective of our study was to map the extent and distribution of normal faults using their morphological expression and magnetic signature, and examine their relationship with paleo-shorelines of the pans. We: (1) Created a hill shade relief map from the SRTM DEM; (2) Extracted regional NW-SE trending topographic profiles across the pans; (3) Constructed displacement profiles for major normal faults; and (4) Created tilt derivative images from the aeromagnetic data. We found that: (1) The northeastern part of the pan is dissected by three morphologically-defined NE-trending normal faults. The along strike continuity of these faults is in the range of 75 and 170 km and they are spaced at ~30 km apart from each other. (2) The topographic profiles suggest that the exposed minimum vertical displacement (EMVD), defined by poorly developed escarpments, is in the range of 0 m and 49 m. (3) The displacement profiles of the faults is characterized by maximum EMVD in the middle of the faults and that it decays towards the fault tips. These faults are also apparent in the aeromagnetic maps where they seem to displace E-W trending Karoo-age dikes. (4) At least the outer paleo-shoreline of the pans is modified by the NE-trending faults. This suggests that the faults are younger than the paleo-shorelines, which is suggested to have been developed between 500 and 100 ka. Traditionally, the southwestern extension of the East African Rift System has been assigned to the

  16. A survey of surveys

    SciTech Connect

    Kent, S.M.

    1994-11-01

    A new era for the field of Galactic structure is about to be opened with the advent of wide-area digital sky surveys. In this article, the author reviews the status and prospects for research for 3 new ground-based surveys: the Sloan Digital Sky Survey (SDSS), the Deep Near-Infrared Survey of the Southern Sky (DENIS) and the Two Micron AU Sky Survey (2MASS). These surveys will permit detailed studies of Galactic structure and stellar populations in the Galaxy with unprecedented detail. Extracting the information, however, will be challenging.

  17. Salinity surveys using an airborne microwave radiometer

    NASA Technical Reports Server (NTRS)

    Paris, J. F.; Droppleman, J. D.; Evans, D. E.

    1972-01-01

    The Barnes PRT-5 infrared radiometer and L-band channel of the multifrequency microwave radiometer are used to survey the distribution of surface water temperature and salinity. These remote sensors were flown repetitively in November 1971 over the outflow of the Mississippi River into the Gulf of Mexico. Data reduction parameters were determined through the use of flight data obtained over a known water area. With these parameters, the measured infrared and microwave radiances were analyzed in terms of the surface temperature and salinity.

  18. Depth to the bottom of magnetic sources (DBMS) from aeromagnetic data of Central India using modified centroid method for fractal distribution of sources

    NASA Astrophysics Data System (ADS)

    Bansal, A. R.; Anand, S. P.; Rajaram, Mita; Rao, V. K.; Dimri, V. P.

    2013-09-01

    The depth to the bottom of the magnetic sources (DBMS) has been estimated from the aeromagnetic data of Central India. The conventional centroid method of DBMS estimation assumes random uniform uncorrelated distribution of sources and to overcome this limitation a modified centroid method based on scaling distribution has been proposed. Shallower values of the DBMS are found for the south western region. The DBMS values are found as low as 22 km in the south west Deccan trap covered regions and as deep as 43 km in the Chhattisgarh Basin. In most of the places DBMS are much shallower than the Moho depth, earlier found from the seismic study and may be representing the thermal/compositional/petrological boundaries. The large variation in the DBMS indicates the complex nature of the Indian crust.

  19. Geochemical, aeromagnetic, and generalized geologic maps showing distribution and abundance of molybdenum and zinc, Golconda and Iron Point quadrangles, Humboldt County, Nevada

    USGS Publications Warehouse

    Erickson, R.L.; Marsh, S.P.

    1972-01-01

    This series of maps shows the distribution and abundance of mercury, arsenic, antimony, tungsten, gold, copper, lead, and silver related to a geologic and aeromagnetic base in the Golconda and Iron Point 7½-minute quadrangles. All samples are rock samples; most are from shear or fault zones, fractures, jasperoid, breccia reefs, and altered rocks. All the samples were prepared and analyzed in truck-mounted laboratories at Winnemucca, Nevada. Arsenic, tungsten, copper, lead, and silver were determined by semiquantitative spectrographic methods by D.F. Siems and E.F. Cooley. Mercury and gold were determined by atomic absorption methods and antimony was determined by wet chemical methods by R.M. O'Leary, M.S. Erickson, and others.

  20. Estimation of Basal Depth of Magnetic Sources from High Resolution Aeromagnetic Data of Middle Niger Basin, Nigeria using Adapted Centroid Technique for Fractal Distribution of Sources

    NASA Astrophysics Data System (ADS)

    Nwankwo, L.

    2015-12-01

    An estimate of depths to the bottom of magnetic sources in the Middle Niger Basin, north-central Nigeria has been made from a recently acquired high-resolution aeromagnetic data using adapted centroid technique for fractal distribution of sources. The result shows that the depth varies between 11.71 and 26.53 km. Deeper values are found in northern and central regions while values as low as 12 km were observed in the southern part. The shallower depths to the bottom of magnetic sources may be representing the thermal/petrological boundaries in the basin. This study is therefore crucial for quantitative understanding of the geo-processes and geothermal parameters in the study area.

  1. Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California. Report on work done from June 1, 1980-November 30, 1980

    SciTech Connect

    Couch, R.; Gemperle, M.

    1982-01-01

    Aeromagnetic measurements made along flightlines oriented east-west and spaced at 1.6-km intervals and along lines oriented north-south and spaced at 8-km intervals, over approximately 30,000 square km of northern California, exhibit crossing errors of less than 5 nanoTeslas. The measurements show short-wavelength magnetic anomalies associated with near-surface volcanics over and east of Lassen Peak and over and north of Mt. Shasta and the Medicine Lake Highlands, longer wavelength anomalies over the Modoc Plateau, and very long wavelength anomalies over the northernmost part of the Great Valley and the easternmost metamorphic rocks of the Klamath Mountains. Anomaly patterns exhibit northwest-southeast trends over the Modoc Plateau and a marked change in character at the juncture of the plateau and the Klamath Mountain and Great Valley complexes.

  2. Aeromagnetic measurements in the Cascade Range and Modoc Plateau of northern California; report on work done from June 1, 1980, to November 30, 1980

    USGS Publications Warehouse

    Couch, Richard; Gemperle, Michael

    1982-01-01

    Aeromagnetic measurements made along flightlines oriented east- west and spaced at 1.6-km intervals and along lines oriented north- south and spaced at 8-km intervals, over approximately 30,000 square km of northern California, exhibit crossing errors of less than 5 nanoTeslas. The measurements show short-wavelength magnetic anomalies associated with near-surface volcanics over and east of Lassen Peak and over .and north of Mt. Shasta and the Medicine Lake Highlands, longer wavelength anomalies over the Modoc Plateau, and very long wavelength anomalies over the northernmost part of the Great Valley and the easternmost metamorphic rocks of the Klamath Mountains. Anomaly patterns, exhibit northwest-southeast trends, over the Modoc Plateau and a marked change in character at the juncture of the plateau and the Klamath Mountain and Great Valley complexes.

  3. Three-dimensional distribution of igneous rocks near the Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska: constraints from regional-scale aeromagnetic data

    USGS Publications Warehouse

    Anderson, Eric D.; Zhou, Wei; Li, Yaoguo; Hitzman, Murray W.; Monecke, Thomas; Lang, James R.; Kelley, Karen D.

    2014-01-01

    Aeromagnetic data helped us to understand the 3D distribution of plutonic rocks near the Pebble porphyry copper deposit in southwestern Alaska, USA. Magnetic susceptibility measurements showed that rocks in the Pebble district are more magnetic than rocks of comparable compositions in the Pike Creek–Stuyahok Hills volcano-plutonic complex. The reduced-to-pole transformation of the aeromagnetic data demonstrated that the older rocks in the Pebble district produce strong magnetic anomaly highs. The tilt derivative transformation highlighted northeast-trending lineaments attributed to Tertiary volcanic rocks. Multiscale edge detection delineated near-surface magnetic sources that are mostly outward dipping and coalesce at depth in the Pebble district. The total horizontal gradient of the 10-km upward-continued magnetic data showed an oval, deep magnetic contact along which porphyry deposits occur. Forward and inverse magnetic modeling showed that the magnetic rocks in the Pebble district extend to depths greater than 9 km. Magnetic inversion was constrained by a near-surface, 3D geologic model that is attributed with measured magnetic susceptibilities from various rock types in the region. The inversion results indicated that several near-surface magnetic sources with moderate susceptibilities converge with depth into magnetic bodies with higher susceptibilities. This deep magnetic source appeared to rise toward the surface in several areas. An isosurface value of 0.02 SI was used to depict the magnetic contact between outcropping granodiorite and nonmagnetic sedimentary host rocks. The contact was shown to be outward dipping. At depths around 5 km, nearly the entire model exceeded the isosurface value indicating the limits of nonmagnetic host material. The inversion results showed the presence of a relatively deep, northeast-trending magnetic low that parallels lineaments mapped by the tilt derivative. This deep low represents a strand of the Lake Clark fault.

  4. Thickness of Santa Fe Group sediments in the Espanola Basin south of Santa Fe, New Mexico, as estimated from aeromagnetic data

    USGS Publications Warehouse

    Phillips, Jeffrey D.; Grauch, V.J.S.

    2004-01-01

    In the southern Espa?ola basin south of Santa Fe, New Mexico, weakly magnetic Santa Fe Group sediments of Oligocene to Pleistocene age, which represent the primary aquifers for the region, are locally underlain by moderately to strongly magnetic igneous and volcaniclastic rocks of Oligocene age. Where this relationship exists, the thickness of Santa Fe Group sediments, and thus the maximum thickness of the aquifers, can be estimated from quantitative analysis of high-resolution aeromagnetic data. These thickness estimates provide guidance for characterizing the ground-water resources in between scattered water wells in this area of rapid urban development and declining water supplies. This report presents one such analysis based on the two-step extended Euler method for estimating depth to magnetic sources. The results show the general form of a north-trending synclinal basin located between the Cerrillos Hills and Eldorado with northward thickening of Santa Fe Group sediments. The increase in thickness is gradual from the erosional edge on the south to a U-shaped Santa Fe embayment hinge line, north of which sediments thicken much more dramatically. Along the north-south basin axis, Santa Fe Group sediments thicken from 300 feet (91 meters) at the hinge line near latitude 35o32'30'N to 2,000 feet (610 meters) at the Cerrillos Road interchange at Interstate 25, north of latitude 35o36'N. The depth analysis indicates that, superimposed on this general synclinal form, there are many local areas where the Santa Fe Group sediments may be thickened by a few hundred feet, presumably due to erosional relief on the underlying Oligocene volcanic and volcaniclastic rocks. Some larger areas of greater apparent thickening occur where the presence of magnetic rocks directly underlying the Santa Fe Group is uncertain. Where magnetic rocks are absent beneath the Santa Fe Group, the thickness cannot be estimated from the aeromagnetic data.

  5. A hybrid hard- and soft-linked fault model for the development of Australian extensional basin systems: Reconciling observations from seismic, aeromagnetic and analogue modelling data

    SciTech Connect

    O'Brien, G.W.; Symonds, P.; Blevin, J. ); Higgins, R.

    1996-01-01

    A series of rift models has been developed for basin systems around Australia, via the interpretation of newly acquired deep crustal seismic and high resolution aeromagnetic data. These models, which incorporate observations on rift architecture, fault geometries, fault orientation, basement fabric/grain, extensional transport direction and reactivation history, have then been iteratively tested by over twenty-five sophisticated analogue modelling experiments. This work has led to the development of a hybrid hard-linked/soft-linked fault model for the Australian margin. In this model, basement grain is the principal control on the rift architecture that develops, with pre-existing fractures acting to establish discrete offsets (hard-linkages) between adjacent extensional faults and rift segments. It is these basement features which produce the rectilinear features which are so common on aeromagnetic data around the Australian margin. With progressively greater extension, the basement-involved, hard-linked system exerts virtually no influence over the type or intensity of faulting within the syn-rift phase, though they do control the fault location. Syn-rift faulting is dominated by [open quotes]soft-linked[close quotes] fault systems, with relay ramps/zones accommodating jumps in the position of the basin margin faults. During basin reactivation (particularly inversion), it is the location and geometry of the underpinning, hard-linked basement features which ultimately control the locations of the traps that develop in the syn- and post-rift section, whereas it is the soft-linked fault system which is the primary control on the fluid migration pathways. Reconciling these concepts provides a set of powerful predictive tools for exploring both frontier and mature basins.

  6. A hybrid hard- and soft-linked fault model for the development of Australian extensional basin systems: Reconciling observations from seismic, aeromagnetic and analogue modelling data

    SciTech Connect

    O`Brien, G.W.; Symonds, P.; Blevin, J.; Higgins, R.

    1996-12-31

    A series of rift models has been developed for basin systems around Australia, via the interpretation of newly acquired deep crustal seismic and high resolution aeromagnetic data. These models, which incorporate observations on rift architecture, fault geometries, fault orientation, basement fabric/grain, extensional transport direction and reactivation history, have then been iteratively tested by over twenty-five sophisticated analogue modelling experiments. This work has led to the development of a hybrid hard-linked/soft-linked fault model for the Australian margin. In this model, basement grain is the principal control on the rift architecture that develops, with pre-existing fractures acting to establish discrete offsets (hard-linkages) between adjacent extensional faults and rift segments. It is these basement features which produce the rectilinear features which are so common on aeromagnetic data around the Australian margin. With progressively greater extension, the basement-involved, hard-linked system exerts virtually no influence over the type or intensity of faulting within the syn-rift phase, though they do control the fault location. Syn-rift faulting is dominated by {open_quotes}soft-linked{close_quotes} fault systems, with relay ramps/zones accommodating jumps in the position of the basin margin faults. During basin reactivation (particularly inversion), it is the location and geometry of the underpinning, hard-linked basement features which ultimately control the locations of the traps that develop in the syn- and post-rift section, whereas it is the soft-linked fault system which is the primary control on the fluid migration pathways. Reconciling these concepts provides a set of powerful predictive tools for exploring both frontier and mature basins.

  7. Aeromagnetic study of the Hengshan-Wutai-Fuping region: Unraveling a crustal profile of the Paleoproterozoic Trans-North China Orogen

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Zhao, Guochun; Shen, Wenlue; Li, Sanzhong; Sun, Min

    2015-11-01

    An integrated crustal profile of the intervening Trans-North China Orogen (TNCO) is one of the key issues to understanding the tectonic evolution of the North China Craton. However, the existing geological studies focus only on the surface-mapping based petrological, geochemical and structural analysis, but lack subsurface geophysical evidence and thus make the crustal profile interpretations ambiguous. In contrast, the current geophysical data covers a very large-scale lithospheric mantle and fails to image the detailed structural pattern of the orogenic crust. To achieve this goal, we present high-resolution aeromagnetic data for the Hengshan-Wutai-Fuping region, the largest exposure of the central TNCO. The reduced-to-pole magnetic anomaly map firstly verifies the regional tectonic subdivision that the high-grade metamorphic terranes (i.e. Hengshan and Fuping Complexes) are consistent with high-magnetic responses and long-wavelength anomalies, intervened by a low-grade terrane (Wutai Complex) characterized by low-magnetic responses and short-wavelength anomalies. 3D Euler deconvolution reveals that the tendencies of the clustered solutions show large consistence with the major structural pattern of the region which is characterized by a fan-shaped doubly-vergent orogenic wedge. Upward continuation further shows that the northwest part of the orogen yields a thicker crust and is most likely located closer to the paleosubduction zone. The new aeromagnetic data, combined with structural, petrological and metamorphic data indicate that an eastward-dipping subduction zone was most possibly active before the collision of the Western and Eastern Blocks, leading to the formation of the TNCO and the final amalgamation of the North China Craton.

  8. Aeromagnetic evidence for a major strike-slip fault zone along the boundary between the Weddell Sea Rift and East Antarctica

    NASA Astrophysics Data System (ADS)

    Jordan, T. A.; Ferraccioli, F.; Ross, N.; Siegert, M. J.; Corr, H.; Leat, P. T.; Bingham, R. G.; Rippin, D. M.; le Brocq, A.

    2012-04-01

    The >500 km wide Weddell Sea Rift was a major focus for Jurassic extension and magmatism during the early stages of Gondwana break-up, and underlies the Weddell Sea Embayment, which separates East Antarctica from a collage of crustal blocks in West Antarctica. Here we present new aeromagnetic data combined with airborne radar and gravity data collected during the 2010-11 field season over the Institute and Moeller ice stream in West Antarctica. Our interpretations identify the major tectonic boundaries between the Weddell Sea Rift, the Ellsworth-Whitmore Mountains block and East Antarctica. Digitally enhanced aeromagnetic data and gravity anomalies indicate the extent of Proterozoic basement, Middle Cambrian rift-related volcanic rocks, Jurassic granites, and post Jurassic sedimentary infill. Two new joint magnetic and gravity models were constructed, constrained by 2D and 3D magnetic depth-to-source estimates to assess the extent of Proterozoic basement and the thickness of major Jurassic intrusions and post-Jurassic sedimentary infill. The Jurassic granites are modelled as 5-8 km thick and emplaced at the transition between the thicker crust of the Ellsworth-Whitmore Mountains block and the thinner crust of the Weddell Sea Rift, and within the Pagano Fault Zone, a newly identified ~75 km wide left-lateral strike-slip fault system that we interpret as a major tectonic boundary between East and West Antarctica. We also suggest a possible analogy between the Pagano Fault Zone and the Dead Sea transform. In this scenario the Jurassic Pagano Fault Zone is the kinematic link between extension in the Weddell Sea Rift and convergence across the Pacific margin of West Antarctica, as the Dead Sea transform links Red Sea extension to compression within the Zagros Mountains.

  9. Modeled Aeromagnetic Anomalies, Controlled By Radar Ice Sounding, As Evidence for Subglacial Volcanic Activity in the West Antarctic Rift System (WR) Beneath the Area of the Divide of the West Antarctic Ice Sheet (WAIS)

    NASA Astrophysics Data System (ADS)

    Behrendt, J. C.

    2014-12-01

    The Thwaites and Pine Island ice shelves, buttressing the WAIS, have passed the turning point as they are eaten away by warmer ocean waters (Joghin et al., 2014; Rignot et al., 2014). There is an increasing evidence (aeromagnetic, radar ice-sounding, high heat flow, subglacial volcanic seismicity, and several exposed and subglacial active volcanoes), for volcanic activity in the WR beneath the WAIS, which flows through it. The 5-km, orthogonally line spaced, central West Antarctica (CWA) aerogeophysical survey defined >400 high amplitude volcanic magnetic anomalies correlated with glacial bed topography. Modeled anomalies defined magnetic properties; interpreted volcanic edifices were mostly removed by the moving ice into which they were erupted. Very high apparent susceptibility contrasts (.001->.3 SI) are typical of measured properties from volcanic exposures in the WAIS area. About 90% of the magnetic sources have normal magnetization in the present field direction. Two explanations as to why the anomalies are not approximately 50% negative: (1) Volcanic activity resulting in these anomalies occurred in a predominantly normal field (unlikely). (2) Sources are a combination of induced and remanent magnetization resulting in anomalies of low amplitude (induced cancels remanent) and are not recognized because they are <100 nT (most probable). About 18 high relief, (~600-2000 m) "volcanic centers" beneath the WAIS surface, probably were erupted subaerially when the WAIS was absent; nine of these are in the general area beneath the divide of the WAIS. A 70-km wide, ring of interpreted subglacial volcanic rocks may define a volcanic caldera underlying thedivide (Behrendt et al., 1998). A 2 km-high subaerially erupted volcano (subglacial Mt Thiel, ~78o30'S, 111oW) ~ 100 km north of the WAISCORE, could be the source an ash layer observed in the core. Models by Tulaczyk and Hossainzadeh (2011) indicate >4mm/yr basal melting beneath the WAIS, supportive of high heat flow

  10. Aeromagnetic map of the Powderhorn wilderness study area and Cannibal Plateau Roadless Area, Gunnison and Hinsdale counties, Colorado

    USGS Publications Warehouse

    Martin, R.A.; Sharp, William N.

    1983-01-01

    The Powderhorn Wilderness Study Area (51,000 acres or 20,640 hectares) and the contiguous Cannibal Plateau Roadless Area (29,500 acres or 11,959 hectares) are on the Gunnison County-Hinsdale County boundary, approximately 50mi (80 km) southwest of Gunnison and a few miles east of Lake City, Colo. Part of the area has been known as the Powderhorn Primitive Area. The mineral resource potential of the study area has been assessed by the U.S. Geological Survey and the U.S. Bureau of Mines; this assessment involved, besides the geologic study and economic appraisal (Sharp and others, 1983), a geophysical survey (this report) by the Geological Survey, and a geochemical survey (Sharp and Lane, 1983) by the Geological Survey and the Bureau of Mines. 

  11. High-Resolution Ground-Based Magnetic Survey of a Buried Volcano: Anomaly B, Amargosa Desert, NV

    NASA Astrophysics Data System (ADS)

    McIlrath, J.; George, O.; Farrell, A. K.; Gallant, E.; Tavarez, S.; Downs, C. M.; Njoroge, M. W.; Wilson, J. A.; Connor, C.; Connor, L.; Kruse, S.

    2015-12-01

    Aeromagnetic surveys over the Amargosa Desert, Nevada, have revealed the presence of several magnetic anomalies that have been interpreted to be caused by buried volcanoes; many of these anomalies have been confirmed by drilling. We present data collected from a high-resolution, ground-based magnetic survey over Anomaly B, the largest of these anomalies, that reveal details about a buried crater and its associated lava flow, not previously observed in the aeromagnetic surveys. These details provide insight into the nature of the eruption and the volume of this buried volcano. Results from non-linear inversion demarcate a crater with a diameter of approximately 700 m and a base approximately 150 m below the ground surface. Coupled with well log data, the inversion results suggest a total volume for the Anomaly B crater area and associated lava flows of approximately 1.0 ± 0.4 km3, based on an estimated lava flow field area of 24 km2 and a lava thickness of 42 ± 15 m.

  12. Petrophysical data and opaque mineralogy of high-grade and retrogressed lithologies: implications for the interpretation of aeromagnetic anomalies in Northern Vestranden, Central Norway

    NASA Astrophysics Data System (ADS)

    Skilbrei, Jan Reidar; Skyseth, Trond; Olesen, Odleiv

    1991-06-01

    A regional aeromagnetic anomaly centred around Roan, Northern Vestranden, Western Gneiss Region, Central Norway, is caused by the presence of high-grade orthogneisses and metabasites with 1-2 vol% magnetite. Granulites are surrounded, and partly covered by amphibolite-facies rocks, which consist of reworked, retrogressed granulite-facies orthogneisses, and bands of metasediments. Prograde metamorphism from amphibolite to granulite facies led to production of magnetite as a result of the breakdown of hydrous (Fe, Mg) Al-silicates. The magnetite occurs as 0.5-1 mm amoeboid grains surrounded by plagioclase and K-feldspar. This magnetite is nearly pure with only a negligible content of ulvospinel (FeTiO 4) in solid solution (aeromagnetic anomalies and geological units allows "mapping" of these units in the offshore areas. Metasedimentary rocks that are downfolded in the orthogneisses show low magnetic susceptibility

  13. Bedrock morphology and structure, upper Santa Cruz Basin, south-central Arizona, with transient electromagnetic survey data

    USGS Publications Warehouse

    Bultman, Mark W.; Page, William R.

    2016-10-31

    The upper Santa Cruz Basin is an important groundwater basin containing the regional aquifer for the city of Nogales, Arizona. This report provides data and interpretations of data aimed at better understanding the bedrock morphology and structure of the upper Santa Cruz Basin study area which encompasses the Rio Rico and Nogales 1:24,000-scale U.S. Geological Survey quadrangles. Data used in this report include the Arizona Aeromagnetic and Gravity Maps and Data referred to here as the 1996 Patagonia Aeromagnetic survey, Bouguer gravity anomaly data, and conductivity-depth transforms (CDTs) from the 1998 Santa Cruz transient electromagnetic survey (whose data are included in appendixes 1 and 2 of this report).Analyses based on magnetic gradients worked well to identify the range-front faults along the Mt. Benedict horst block, the location of possibly fault-controlled canyons to the west of Mt. Benedict, the edges of buried lava flows, and numerous other concealed faults and contacts. Applying the 1996 Patagonia aeromagnetic survey data using the horizontal gradient method produced results that were most closely correlated with the observed geology.The 1996 Patagonia aeromagnetic survey was used to estimate depth to bedrock in the upper Santa Cruz Basin study area. Three different depth estimation methods were applied to the data: Euler deconvolution, horizontal gradient magnitude, and analytic signal. The final depth to bedrock map was produced by choosing the maximum depth from each of the three methods at a given location and combining all maximum depths. In locations of rocks with a known reversed natural remanent magnetic field, gravity based depth estimates from Gettings and Houser (1997) were used.The depth to bedrock map was supported by modeling aeromagnetic anomaly data along six profiles. These cross sectional models demonstrated that by using the depth to bedrock map generated in this study, known and concealed faults, measured and estimated magnetic

  14. Evaluation of Curie-point depths, geothermal gradients and near-surface heat flow from high-resolution aeromagnetic (HRAM) data of the entire Sokoto Basin, Nigeria

    NASA Astrophysics Data System (ADS)

    Nwankwo, Levi I.; Shehu, Amada T.

    2015-10-01

    An evaluation of Curie-point depths, geothermal gradients and near-surface heat flow has been carried out from the spectral analysis of the recently acquired high resolution aeromagnetic (HRAM) data of the entire Sokoto Basin in northwestern Nigeria. The HRAM data was divided into twenty two (22) overlapping blocks and each block analyzed using the spectral centroid method to obtain depth to the top, centroid and bottom of magnetic sources. The depth values were subsequently used to evaluate the Curie-point depth (CPD), geothermal gradient and near-surface heat flow in the study area. The result shows that the CPD varies between 11.13 and 27.83 km with an average of 18.57 km, the geothermal gradient varies between 20.84 and 52.11 °C/km with an average of 33.99 °C/km, and the resulting heat flow varies between 52.11 and 130.28 mW m- 2 with an average of 84.97 mW m- 2. Such heat flow values are suggestive of anomalous geothermal conditions and are recommended for detailed geothermal exploration in the basin.

  15. Precambrian Basement Surface Estimation using Coupled 3D Modeling of Gravity and Aeromagnetic Data in Southeastern Wisconsin and Fond Du Lac County

    NASA Astrophysics Data System (ADS)

    Skalbeck, J.; Koski, A. J.

    2011-12-01

    Increased concerns about groundwater resources in Wisconsin have brought about the need for better understanding of the subsurface geologic structure that lead to developing conceptual hydrogeologic models for numerical simulation of groundwater flow. Models are often based on sparse data from well logs usually located large distances apart and limited in depth. Model assumptions based on limited spatial data typically requires simplification that may add uncertainty to the simulation results and the accuracy of a groundwater model. This research provides another tool for the groundwater modeler to better constrain the conceptual model of a hydrogeologic system. The area near the Waukesha Fault in southeastern Wisconsin provides an excellent research opportunity for our proposed approach because of the strong gravity and aeromagnetic anomalies associated with the fault, the apparent complexity in fault geometry, and uncertainty in Precambrian basement depth and structure. Precambrian basement surface throughout Fond du Lac County is known to be very undulated and this uneven basement topography controls water well yields and zones of stagnant water. Therefore, an accurate estimation of the basement topography in Fond Du Lac County is vital to determining ground water flow and quality of groundwater in this region.

  16. Using high-resolution aeromagnetic data to recognise and map intra-sedimentary volcanic rocks and geological structures across the Cretaceous middle Benue Trough, Nigeria

    NASA Astrophysics Data System (ADS)

    Anudu, Goodluck K.; Stephenson, Randell A.; Macdonald, David I. M.

    2014-11-01

    Recently acquired high-resolution aeromagnetic data over the Cretaceous middle Benue Trough of Nigeria have been analysed employing various edge-enhancement (magnetic derivative) methods: vertical derivatives, total horizontal derivative, analytic signal, and total horizontal derivative of tilt derivative. The study was aimed at mapping intra-sedimentary volcanic rocks and their areal extents/distribution as well as delineating geological structures, their structural trends and tectonic implications. The magnetic derivative anomaly maps produced in this project greatly enhanced the high amplitude, short-wavelength (high wavenumber) anomalies associated with the surface/near-surface intra-sedimentary volcanic rocks and associated geological structures. The maps show that volcanic rocks of Late Cretaceous to Palaeocene age are much more widespread than implied by surface geological mapping, with an areal extent of greater than 12,000 km2 in the relatively shallow subsurface. The results also highlight some known and several previously unknown geological lineaments. Rose (azimuth-frequency) plots of orientations of geological structures show trends being predominantly NE-SW, NW-SE and ESE-WNW with minor ENE-WSW and N-S trends. These main groups of structural trends are associated with the Brasiliano/Pan-African orogeny (600 ± 200 Ma) and likely predate rifting of the Gondwana supercontinent. They may have been enhanced during continental break-up in Late Jurassic to Early Cretaceous.

  17. Tectonics of the Venezuelan Borderland; An interpretation of magnetometer surveys

    SciTech Connect

    Young, G.A. )

    1993-02-01

    Over 46,000 km of shipborne magnetic surveys and over 64,000 km of aeromagnetic surveys cover the offshore Venezuelan Borderland. The information from these surveys has been assembled into a total intensity map, together with its vertical gradient reduction, and interpreted with respect to the regional tectonics. The distribution and shape of the igneous intrusions and metamorphic rock masses can be clearly recognized as well as the major sedimentary troughs. Areas with similar frequencies and trend directions have been grouped into magnetic provinces in order to better delineate the different structural styles and picture the forces that acted on the basement rocks. The most prominent structures of the Borderland are the nappes and the major transcurrent faults, along which the provinces moved toward the southeast. In the Margarita Province the Margarita-Testigos and La Blanqilla nappes are the most conspicuous. The Delta Province, to the East, is characterized by the complex compression zones that have moved southeastward along the border of the craton. The La Vela region to the West comprises a complex of overriding magnetic provinces. In the exploration for traps with possible accumulations of hydrocarbons, the interpretation of the vertical gradient is the most important as it provides considerable detail on structural patterns. The structures determined by vertical gradient maps coincide very well with those determined by seismic methods in those areas covered by seismic, and thusly, the magnetic maps serve as a reliable guide to structures in areas not yet covered by seismic surveys.

  18. Digital data from the Great Sand Dunes airborne gravity gradient survey, south-central Colorado

    USGS Publications Warehouse

    Drenth, B.J.; Abraham, J.D.; Grauch, V.J.S.; Labson, V.F.; Hodges, G.

    2013-01-01

    This report contains digital data and supporting explanatory files describing data types, data formats, and survey procedures for a high-resolution airborne gravity gradient (AGG) survey at Great Sand Dunes National Park, Alamosa and Saguache Counties, south-central Colorado. In the San Luis Valley, the Great Sand Dunes survey covers a large part of Great Sand Dunes National Park and Preserve. The data described were collected from a high-resolution AGG survey flown in February 2012, by Fugro Airborne Surveys Corp., on contract to the U.S. Geological Survey. Scientific objectives of the AGG survey are to investigate the subsurface structural framework that may influence groundwater hydrology and seismic hazards, and to investigate AGG methods and resolution using different flight specifications. Funding was provided by an airborne geophysics training program of the U.S. Department of Defense's Task Force for Business & Stability Operations.

  19. A regional gravity survey of the Cuyuna Iron Range, Minnesota

    USGS Publications Warehouse

    Durfee, George Austin

    1957-01-01

    A regional gravity survey of the Cuyuna Iron Range, Minnesota, was conducted during the summer of 1955 by the U. S. Geological Survey. It was believed that gravity data would aid in the understanding of the major structures of the range. It was found that synclinal and steeply dipping structures produced positive gravity anomalies while anilclinal structures produced negative anomalies. This principle was noted in areas of well known geology and then applied to outlying areas of the district. The outstanding gravity feature is a narrow positive anomaly extending from south of Brainerd eastward through Aitkin, the axis of the anomaly being somewhat south of the South Range. This gives support to the theory that the Biwabik formation passes under the stratigraphically higher South Range member as a synclinal structure. However, this anomaly is also explained using one main iron formation and assuming an anticlinal structure between the North and South Ranges and a syncline between the South Range and Bay Lake. A large magnitude negative gravity anomaly north of Mille Lacs is postulated to result from an intrusive mass extending to the erosion surface. Aeromagnetics are used to strengthen the gravity interpretation. The need is realized for additional regional gravity coverage to the east of the area Included in this survey and a detailed gravity study of the area between the North and South Ranges.

  20. Three decades of BGR airborne geophysical surveys over the polar regions - a review

    NASA Astrophysics Data System (ADS)

    Damaske, Detlef

    2013-04-01

    The Federal Institute for Geosciences and Natural Resources (BGR) has been conducting geological polar research since 1979. A few years later BGR engaged in airborne geophysical projects. Investigation of the lithosphere of the continent and the continental margins was one of the key issues for BGR. Right from the beginning geophysical research was closely associated with the geological activities. The GANOVEX (German Antarctic North Victoria Land Expedition) program combined geological research with geophysical (mainly airborne) investigations. This proved to be a fruitful approach to many of the open questions regarding the tectonic development of the Ross Sea region. Aeromagnetic surveys evolved into a powerful tool for identifying geological structures and following them underneath the ice covered areas - not accessible to direct geological investigations. To achieve this aim it was essential to lay out these surveys with a relatively closely spaced line separation on the expense of covering large areas at the same time. Nevertheless, over many years of continues research areas of more than a just regional extent could be covered. This was, however, only possible through international collaboration. During the first years, working in the Ross Sea area, the cooperation with the US and Italian programs played a significant role, especially the GITARA (German-Italian Aeromagnetic Research in Antarctica) program has to be mentioned. GEOMAUD (Geoscientific Expedition to Dronning Maud Land) and the German-Australian joint venture PCMEGA (Prince Charles Mountains Expedition of Germany & Australia) expanded research activities to the East Antarctic shield area. In the International Polar Year (IPY), BGR played a leading role in the international project AGAP (Antarctica's GAmburtsev Province) as part of the main topic "Venture into Unknown Regions". AGAP was jointly conducted by the USA, Great Britain, Australia, China and Germany. While in the Ross Sea area even

  1. Investigating the Influence of Pre-Existing Basement Structures on the Propagation of the Malawi Rift using SRTM, RADARSAT, and Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Robertson, K.; Atekwana, E. A.; Abdelsalam, M. G.; Laó-Dávila, D. A.

    2015-12-01

    The Malawi rift is a Neogene, amagmatic rift located where the Western Branch of the East Africa Rift System (EARS) terminates. In more mature rifts, magmatism is frequently recognized as a driving factor in rift propagation; however, the amagmatic nature of the Malawi rift permits investigation into the relationship between pre-existing structures and current rift propagation, without the influence of magmatism. To map surface structures, we used Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) and RADARSAT imagery over southern Malawi. To process the SRTM data, we applied edge enhancing filters and derivatives, and extracted topographic profiles to examine scarp height and minimum vertical exposed displacement. We mapped morphologically-defined structures by filtering the RADARSAT imagery using an enhanced lee filter to reduce noise and a Laplacian filter for edge enhancement. To examine Precambrian basement structures, we filtered aeromagnetic data using vertical and horizontal derivatives, tilt derivative, and analytic signal to create magnetic anomaly maps. Surface mapping indicated three primary trends in the southern Malawi rift: NW-SE (dominant), NE-SW, both of which are most likely the remnants of Mesozoic Karoo rifting, and a NNE-SSW trend seen in Neogene rifting. The Precambrian basement structural mapping also reveals three primary trends: WNW-ESE, NE-SW, and NW-SE. Ductile deformation causes the dominant basement fabric to change, switching polarity as the rift propagated southward from NE-SW orientation to NW-SE and WNW-ESE orientations, and back to a NE-SW orientation. In general, the surficial structures follow this trend. In some areas, however, the more recent rifting cut across pre-existing basement structures, possibly due to rheological heterogeneities or selective strain partitioning. Nonetheless, pre-existing basement structures played a critical role in strain localization and fault propagation in Malawi. However

  2. Investigation of the deep crustal structure and magmatic activity at the NW Hellenic Volcanic Arc with 3-D aeromagnetic inversion and seimotectonic analysis.

    NASA Astrophysics Data System (ADS)

    Efstathiou, Angeliki; Tzanis, Andreas; Chailas, Stylianos; Stamatakis, Michael

    2013-04-01

    We report the results of a joint analysis of geophysical (aeromagnetic) and seismotectonic data, applied to the investigation of the deep structure, magmatic activity and geothermal potential of the north-western stretches of the Hellenic Volcanic Arc (HVA). The HVA is usually considered to be a single arcuate entity stretching from Sousaki (near Corinth) at the NW, to Nisyros Island at the SE. However, different types of and their ages indicate the presence of two different volcanic groups. Our study focuses on the northern part of the west (older) volcanic group and includes the Crommyonian (Sousaki) volcanic field at the west end of Megaris peninsula (east margin on the contemporary Corinth Rift), the Aegina and Methana volcanic complex at the Saronic Gulf, where typical Quaternary calc-alkaline volcanics predominate, and the Argolid peninsula to the south and south-west. In addition to the rocks associated with Quaternary volcanism, the study area includes a series of Mesozoic ultramafic (ophiolitic) outcrops at the Megaris peninsula, to the north and north-east of the Crommyonian volcanic field, as well as throughout the Argolid. A major deep structural and tectonic feature of the study area, and one with profound influence on crustal deformation and the evolution of rapidly deforming extensional structures like the Corinth Rift and the Saronic Gulf, is the local geometry and dynamics of the African oceanic crust subducting beneath the Aegean plate. Locally, the subducting slab has a NNW strike and ENE plunge, with the dip angle changing rapidly (steepening) approx. beneath the Argolid. The aeromagnetic data was extracted from the recently (re)compiled aeromagnetic map of Greece (Chailas et al, 2010) and was inverted with the UBC-GIF magnetic inversion suite (Li and Oldenburg, 1996). The inversion included rigorous geological constraints introduced by means of numerous in-situ magnetic susceptibility measurements. The inversion has imaged several isolated

  3. Mineral resource potential map of the Pecos Wilderness, Santa Fe, San Miguel, Mora, Rio Arriba, and Taos counties, New Mexico

    USGS Publications Warehouse

    Moench, R.H.; Lane, M.E.

    1988-01-01

    This map is based on geologic and geochemical studies and mine and prospect investigations that were done principally in 1977 and 1979-80 (U.S. Geological Survey, U.S. Bureau of Mines, and New Mexico Bureau of Mines and Mineral Resources, 1980; Lane, 1980; Moench and Robertson, 1980; Moench, Robertson, and Sutley, 1980; Moench and Erickson, 1980; Moench, Grambling, and Robertson, 1988; Moench, Sutley, and Erickson, 1988; Erickson, Sutley, and Moench, 1986). An aeromagnetic survey covering almost all of the Pecos Wilderness was flown in 1970. The resulting aeromagnetic map was published by Moench and others (1980) and interpreted in that report by Lindreth Cordell. Cordell found no correlation between magnetic features and geologic terraines having mineral resource potential.

  4. Helicopter EM (ZTEM-VTEM) survey results over the Nuqrah copper-lead-zinc-gold SEDEX massive sulphide deposit in the Western Arabian Shield, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Legault, Jean M.; Izarra, Carlos; Prikhodko, Alexander; Zhao, Shengkai; Saadawi, Emad M.

    2015-10-01

    Magnetic and electromagnetic (EM) results from two helicopter EM surveys, a time-domain (VTEM) and AFMAG (ZTEM), are compared over the Nuqrah sedimentary exhalative (SEDEX) massive sulphide deposits in the Western Arabian Shield of the Kingdom of Saudi Arabia. The magnetic and EM data from both surveys map the major controlling structures that host the Nuqrah North and South deposits. Neither Nuqrah deposits stand out as distinctive aeromagnetic anomalies, but both EM surveys define the massive sulphide mineralised vent and bedded portions of the SEDEX orebodies. ZTEM is interpreted to be more capable in defining the larger, lower conductance and less mineralised distal portions of the SEDEX system. The modelled ZTEM also defines a down-dip extension of the Nuqrah South zone below a depth of 750 m.

  5. Structure, composition and thermal state of the crust in Brazil. [geomagnetic survey

    NASA Technical Reports Server (NTRS)

    Pacca, I. I. G. (Principal Investigator); Shukowsky, W.

    1981-01-01

    Aeromagnetic survey data of the Minas Gerais areas were analyzed and compared with MAGSAT anomaly data. Initially the data set was used to determine the thickness of the magnetized crust. The value obtained is in agreement with crustal models derived from deep seismic sounding and gravity data, indicating that the bottom of the magnetized layer occurs close to the Moho transition. An analysis of the long wavelength pattern indicates that the anomalies form a series of lineations along the magnetic E-W. These are shown to be the result of attenuation. On the MAGSAT total intensity map localized anomalies are superimposed onto an anomaly background formed by alternating positive and negative patches. Implementation and testing of analysis software for MAGSAT data are also discussed.

  6. Aeromagnetic anomalies and discordant lineations beneath the Niger Delta: Implications for new fracture zones and multiple sea-floor spreading directions in the meso-Atlantic' Gulf of Guinea cul-de-sac

    SciTech Connect

    Babalola, O.O.; Gipson, M. Jr. )

    1991-06-01

    An aeromagnetic contour map compiled over shallow water and onshore portions of the Nigerian continental margin, shows several elongate, long-wavelength anomaly closures with some alternating polarity, separated by steep gradient, NE lineations. The lineations are interpreted as new fracture zones or extensions of previously mapped ones. The NE trend in the western delta region is concordant with the fracture zone trends of the deeper Gulf of Guinea. Aeromagnetic lineations of the SE Niger Delta Basin however, discordantly trend ENE. Their termination against the former, is interpreted as evidence of early sea-floor spreading in a ENE-WSW direction in addition to the well documented NE-SW spreading of the Gulf of Guinea and the rest of the meso-Atlantic sea-floor; The geophysical crustal structure indicate the existence of two Early Cretaceous triple junctions beneath the Niger Delta Basin. The two triple-junctions further support the hypothesis that the African continent was a multi-plate system (in the Niger Delta region) during the early opening of the Atlantic.

  7. Potential field and electromagnetic studies: Introduction

    SciTech Connect

    Goldstein, N.E.

    1987-03-01

    Several aeromagnetic surveys have been flown over Long Valley at different altitudes and line spacings. The one most often referred to was a high level (4 km or 13,200 feet above sea level barometric survey) flown by the USGS in 1973 along E-W lines spaced 1.7 km apart. Investigators attempted a quantitative interpretation of the data, and suggested that extensive post-caldera hydrothermal activity may have drastically altered the composition of the titanomagnetites in the Bishop Tuff, causing the magnetic low in the area of the resurgent dome. Others have reported in informal conversations, as is now supported by holes M-1 and 44-016, that the low in the western part of the caldera is the result of lower magnetization of the post-caldera volcanics and a large wedge of Paleozoic metasediments that floor the caldera. The true nature of the magnetic high on the eastern flank of the resurgent dome has been revealed by recent paleomagnetic work and from a detailed aeromagnetic survey flown 400 feet above terrain for the USGS in 1979. 6 refs., 2 figs.

  8. On the origin of the Amerasia Basin and the High Arctic Large Igneous Province—Results of new aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Døssing, A.; Jackson, H. R.; Matzka, J.; Einarsson, I.; Rasmussen, T. M.; Olesen, A. V.; Brozena, J. M.

    2013-02-01

    The history of the 2.5 million km2 Amerasia Basin (sensu lato) is in many ways the least known in the global tectonic system. Radically different hypotheses proposed to explain its origin are supported only by inconclusive and/or indirect observations and several outstanding issues on the origin of the Basin remain unaddressed. The difficulty lies in the geodynamic evolution and signature of the Basin being overprinted by excess volcanism of the Alpha-Mendeleev Ridge complex, part of the High Arctic Large Igneous Province (HALIP) and one of the largest (>1 million km2) and most intense magmatic and magnetic complexes on Earth. Here, we present the results of a 550,000 km2 aerogeophysical survey over the poorly explored Lomonosov Ridge (near Greenland) and adjoining Amerasia and Eurasia Basins that provides the first direct evidence for consistent linear magnetic features between the Alpha and Lomonosov Ridges, enabling the tectonic origin of both the Amerasia Basin and the HALIP to be constrained. A landward Lower Cretaceous (∼138-125(120) Ma) giant dyke swarm (minimum 350×800 km2) and tentative oceanward Barremian (or alternatively lower Valanginian-Barremian) seafloor spreading anomalies are revealed. Prior to Cenozoic opening of the Eurasia Basin the giant dyke swarm stretched from Franz Josef Land to the southern Alpha Ridge and possibly further to Queen Elisabeth Islands, Canada. The swarm points towards a 250-km-wide donut-shaped anomaly on the southern Alpha Ridge, which we propose was the centre of the HALIP mantle plume, suggesting that pronounced intrusive activity, associated with an Alpha Ridge mantle plume, took place well before the Late Cretaceous Superchron and caused continental breakup in the northern Amerasia Basin. Our results imply that at least the southern Alpha Ridge as well as large parts of the area between the Lomonosov and southern Alpha Ridges are highly attenuated continental crust formed by poly-phase breakup with LIP volcanic

  9. Survey Says

    ERIC Educational Resources Information Center

    McCarthy, Susan K.

    2005-01-01

    Survey Says is a lesson plan designed to teach college students how to access Internet resources for valid data related to the sexual health of young people. Discussion questions based on the most recent available data from two national surveys, the Youth Risk Behavior Surveillance-United States, 2003 (CDC, 2004) and the National Survey of…

  10. Aeromag survey finds features along central Texas overthrust

    SciTech Connect

    Seewald, K.O. ); Rolf, E.G.

    1992-05-18

    This paper reports on the Ouachita thrust belt of central Texas which appears to have great potential based on a recent aeromagnetic survey. The Strawn basin of central Texas has had periodic, selective seismic surveys and limited drilling. About 60 wells have been drilled to Ordovician Ellenburger (one well per 96 sq miles). Only 26 of these penetrated more than 200 ft of Ellenburger, and of that number only eight drilled through Ellenburger (one well per 730 sq miles). It would be safe to say the Ellenburger has not been properly evaluated. Some of the best recovery zones in West Texas fields are more than 600 ft below the top of Ellenburger. Although there is no commercial production to date, there has been a significant gas reserve confirmation. The Kirby 1 Box in Williamson County, drilled in 1981, confirmed what the Shell 1 Purcell tested in 1954. It is situated on a highly faulted, gas charged anticline having more than 450 ft of gas column with 150 ft of net porosity and recoverable reserve potential of 60-100 bcf. The Kirby well was completed in 1982 with a flow rate of 250 Mcfd of gas. The well was shut in until 1989, when a three week flow test averaged more than 800 Mcfd. The well is again shut in.

  11. Detailed petrophysical characterization enhances geological mapping of a buried substratum using aeromagnetic and gravity data; application to the southwestern Paris basin

    NASA Astrophysics Data System (ADS)

    Baptiste, Julien; Martelet, Guillaume; Faure, Michel; Beccaletto, Laurent; Chen, Yan; Reninger, Pierre-Alexandre

    2016-04-01

    Mapping the geometries (structure and lithology) of a buried basement is a key for targeting resources and for improving the regional geological knowledge. The Paris basin is a Mesozoic to Cenozoic intraplate basin set up on a Variscan substratum, which crops out in the surrounding massifs. We focus our study on the southwestern part of the Paris basin at its junction with the Aquitaine basin. This Mezo-Cenozoic cover separates the Armorican Massif and the Massif Central which compose of several litho-tectonic units bounded by crustal-scale shear zones. In spite of several lithological and structural correlations between various domains of the two massifs, their geological connection, hidden below the Paris basin sedimentary cover, is still largely debated. Potential field geophysics have proven effective for mapping buried basin/basement interfaces. In order to enhance the cartographic interpretation of these data, we have set up a detailed petrophysical library (field magnetic susceptibility data and density measurements on rock samples) of the Paleozoic rocks outcropping in the Variscan massifs. The combination of aeromagnetic and gravity data supported by the petrophysical signatures and field/borehole geological information, is carried out to propose a new map of the architecture of the Variscan substratum. The new synthetic map of geophysical signature of the Paris basin basement combines: i) the magnetic anomaly reduced to the pole, ii) the vertical gradient of the Bouguer anomaly and iii) the tilt derivative of the magnetic anomaly reduced to the pole. Based on this information, the Eastern extension of the major shear zones below the sedimentary cover is assessed. The petrophysical signatures were classified in three classes of magnetic susceptibility and density: low, intermediate and high. Basic rocks have high magnetization and density values whereas granite, migmatite and orthogneiss show low magnetization and density values, Proterozoic and Paleozoic

  12. Signature of hydrothermal alteration in ground-magnetic surveys at Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Bouligand, C.; Glen, J. M.; McPhee, D. K.

    2011-12-01

    Yellowstone National Park (YNP) hosts a very large hydrothermal system with over 10,000 thermal features. Although hydrothermal alteration in YNP has been extensively studied with field observations, remote-sensing imagery, and core drilling, the volume and geometry of hydrothermal systems at depth remain poorly constrained. Magnetic surveys can help to investigate buried hydrothermal alteration as demonstrated by the high-resolution aeromagnetic survey of YNP (Finn and Morgan, J. Volcanol. Geotherm. Res., 115, 207-231, 2002). Results of this survey show that magnetic lows extend over and beyond areas of hydrothermal activity. This suggests large volumes of buried demagnetized rocks due to hydrothermal alteration of the volcanic substratum. Although the interpretation of magnetic anomalies is non-unique, Finn and Morgan (2002) used these magnetic lows to estimate a minimum volume of buried altered rock assuming complete demagnetization of the substratum. This aeromagnetic survey was of relatively high resolution (flight line spacing < 500 m and flight elevation <350 m above ground), but it was insufficient for detailed mapping of individual thermal areas. In order to obtain a closer look at several areas, we performed ground-based magnetic surveys within YNP using a cesium-vapor magnetometer along 4-5 km long transects crossing four thermal areas (Norris Geyser Basin, Lower Geyser Basin, Lone Star Geyser Basin, and Smoke Jumper Hot-springs). We also performed a detailed survey over an area of about 800 m x 500 m around Lone Star Geyser. We also collected gravity data to help characterize the subsurface geologic structures and performed magnetic susceptibility, magnetic remanence, and density measurements on rock samples collected in the field and from drill cores collected in 1967-1968 to characterize physical properties of fresh and altered geologic units. The long magnetic transects show that magnetic anomalies are damped in altered areas suggesting a significant

  13. Survey of Propulsion Technologies Applicable to Cubesats

    NASA Technical Reports Server (NTRS)

    Mueller, Juergen; Hofer, Richard; Ziemer, John

    2010-01-01

    At present, no Cubesat has flown in space featuring propulsion. This was acceptable as long as CubeSats were flown mostly as university experiments. As CubeSats become of interest to other users in the government and industry communities as well, a larger range of capabilities may be required than exhibited so far, while maintaining the uniqueness of the Cubesat platform. Propulsion capability is crucial in increasing mission capabilities of future CubeSats, such as orbit change and raising, formation flying, proximity operations, fine attitude control, or drag-make-up and de-orbit. While some of these tasks may be accomplished with propellantless devices, their applications are limited, applicable mostly to a single task, and bear their own risks. In this study, a survey was conducted of propulsion technologies applicable to CubeSats. Only few off-the-shelf design solutions exist today. The survey was thus expanded to such devices as well that are under significant development, and are approaching the required design envelope for CubeSats with respect to mass, volume, and power. In some cases, such as electric propulsion devices, CubeSat architectures themselves may need to be adapted, required to feature deployable solar arrays to increase power capabilities. Given the vast scope of this survey, only thruster technologies could be surveyed. However, valves and other feed system components, as well as their integration, are equally important, but have to be left to a future survey. Three major propulsion technology areas applicable to CubeSats emerged when conducting this review: (1) Existing technologies, such as butane systems, pulsed plasma thrusters, and vacuum arc thrusters are applicable to CubeSats today with no or only minor changes, (2) New thruster technologies under significant development, such as hydrazine monopropellant systems, ion engines, or colloid thrusters could be adapted to CubeSats with some further development, especially also in other

  14. High-Altitude Magnetic Survey Over the United States

    NASA Astrophysics Data System (ADS)

    Hildenbrand, T. G.; Keller, G.; Pellerin, L.; Phillips, J.; Ravat, D.; Sabaka, T.

    2003-12-01

    The year 2004 offers an exciting and cost-effective opportunity to acquire a high-altitude magnetic data set over the U.S. A national mission is presently being planned to collect IFSAR imagery in addition to total and vector magnetic field data at an altitude of about 15 km. High-altitude magnetic data, needed as a reference field to properly level the U.S. low-altitude magnetic data set (0.3 km altitude), will also provide new insights on fundamental tectonic and thermal processes, thereby enabling a new view of the structural and lithologic framework of continental and offshore regions. A correctly merged, low-altitude magnetic database, using high-altitude magnetic data as a reference field, will be one of the most important legacies of a high-altitude magnetic mission, as it will greatly expand the utility of the invaluable U.S. magnetic data. However, the high-altitude data also have considerable independent scientific value. These unique data will bridge the spectral gap between the spectrums of the low-altitude aeromagnetic and satellite magnetic data. Based on our understanding of the magnetic properties of the lithosphere, the high-altitude data will clearly aid in the solution of a broad range of applied Earth science issues related to: the conundrum of long-wavelength magnetic anomalies; geologic and tectonic processes of crustal accretion and evolution; thermal and mechanical properties of the lithosphere; societal concerns including localization of favorable areas for mineral, energy, and thermal resources; and mitigation of earthquake and volcanic hazards. The wavelength band of a high-altitude survey will be particularly helpful in studying the lower crust--its composition, structure, and thermal regime--and large geologic/tectonic structures, such as basement terranes. In addition, these results will provide significant new constraints for geological interpretation of complementary regional topographic, seismic, electromagnetic, gravity, and heat

  15. Theory Survey or Survey Theory?

    ERIC Educational Resources Information Center

    Dean, Jodi

    2010-01-01

    Matthew Moore's survey of political theorists in U.S. American colleges and universities is an impressive contribution to political science (Moore 2010). It is the first such survey of political theory as a subfield, the response rate is very high, and the answers to the survey questions provide new information about how political theorists look…

  16. General aviation activity and avionics survey. Annual summary report, CY 1985

    SciTech Connect

    Not Available

    1987-03-01

    This report presents the results and a description of the 1985 General Aviation Activity and Avionics Survey. The survey was conducted during 1986 by the FAA to obtain information on the activity and avionics of the United States registered general aviation aircraft fleet, the dominant component of civil aviation in the U.S. The survey was based on a statistically selected sample of about 10.3 percent of the general aviation fleet. A responses rate of 63.7 percent was obtained. Survey results based upon response but are expanded upward to represent the total population. Survey results revealed that during 1985 an estimated 34.1 million hours of flying time were logged and 88.7 million operations were performed by the 210,654 active general aviation aircraft in the U.S. fleet. The mean annual flight time per aircraft was 158.2 hours. The active aircraft represented about 77.9 percent of the registered general aviation fleet. The report contains breakdowns of these and other statistics by manufacturer/model group, aircraft, state and region of based aircraft, and primary use. Also included are fuel consumption, lifetime airframe hours, avionics, engine hours, and miles flown estimates, as well as tables for detailed analysis of the avionics capabilities of the general aviation fleet. New to the report this year are estimates of the number of landings, IFR hours flown, and the cost and grade of fuel consumed by the GA fleet.

  17. Role Stratospheric Balloon Magnetic Surveys in Development of Analytical Global Models of the Geomagnetic Field

    NASA Astrophysics Data System (ADS)

    Brekhov, O. M.; Tsvetkov, Yu. P.; Ivanov, V. V.; Filippov, S. V.; Tsvetkova, N. M.

    2015-09-01

    The results of stratospheric balloon gradient geomagnetic surveys at an altitude of ‘-~3O km with the use of the long (6 km) measuring base oriented along the vertical line are considered. The purposes of these surveys are the study of the magnetic field formed by deep sources, and the estimation of errors in modern analytical models of the geomagnetic field. The independent method of determination of errors in global analytical models of the normal magnetic field of the Earth (MFE) is substantiated. The new technique of identification of magnetic anomalies from surveys on long routes is considered. The analysis of gradient magnetic surveys on board the balloon, revealed the previously unknown features of the geomagnetic field. Using the balloon data, the EMM/720 model of the geomagnetic field (http://www.ngdc.noaa.gov/geomag/EMM) is investigated, and it is shown that this model unsatisfactorily represents the anomalous MFE, at least, at an altitude of 30 km, in the area our surveys. The unsatisfactory quality of aeromagnetic (ground-based) data is also revealed by the method of wavelet analysis of the ground-based and balloon magnetic profiles. It is shown, that the ground-based profiles do not contain inhomogeneities more than 1 30 km in size, whereas the balloon profiles (1000 km in the strike extent) contain inhomogeneities up to 600 km in size an the location of the latte coincides with the location of the satellite magnetic anomaly. On the basis of balloon data is shown, it that low-altitude aeromagnetic surveys, due to fundamental reasons, incorrectly reproduce the magnetic field of deep sources. This prevents the reliable conversion of ground-based magnetic anomalies upward from the surface of the Earth. It is shown, that an adequate global model of magnetic anomalies in the circumterrestrial space, developed up to 720 spherical harmonics, must be constructed only in accordance with the data obtained at satellite and stratospheric altitudes. Such a model

  18. Inertial instrument system for aerial surveying

    USGS Publications Warehouse

    Brown, R.H.; Chapman, W.H.; Hanna, W.F.; Mongan, C.E.; Hursh, J.W.

    1985-01-01

    An inertial guidance system for aerial surveying has been developed under contract to the U.S. Geological Survey. This prototype system, known as the aerial profiling of terrain (APT) system, is designed to determine continuously the positions of points along an aircraft flight path, or the underlying terrain profile, to an accuracy of + or - 0.5 ft (15 cm) vertically and + or - 2 ft (61 cm) horizontally. The system 's objective thus is to accomplish, from a fixed-wing aircraft, what would traditionally be accomplished from ground-based topographic surveys combined with aerial photography and photogrammetry. The two-part strategy for measuring the terrain profile entails: (1) use of an inertial navigator for continuous determination of the three-coordinate position of the aircraft, and (2) use of an eye-safe pulsed laser profiler for continuous measurement of the vertical distance from aircraft to land surface, so that the desired terrain profile can then be directly computed. The APT system, installed in a DeHavilland Twin Otter aircraft, is typically flown at a speed of 115 mph (105 knots) at an altitude of 2,000 ft (610 m) above the terrain. Performance-evaluation flights have shown that the vertical and horizontal accuracy specifications are met. (USGS)

  19. A Shuttle/SpaceLab RF environment survey facility

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Prince, R. E.; Mcgregor, D. N.

    1974-01-01

    This paper describes some of the basic system considerations of a proposed experiment for monitoring and measuring the global electromagnetic radiation environment. RF spectrum coverage for this spaceborne survey facility is anticipated to be quite broad and will include selected frequency bands ranging from UHF to millimeter waves. By establishing this RF environment survey facility, a broad data base of useful electromagnetic field intensity information will be developed. This, in turn, should help both the regulatory agencies and user community in terms of future frequency planning and system design by avoiding unwarranted interference. It is proposed that this experiment be flown as a future test bed during the Shuttle/Spacelab era for continuously gathering and updating information on earth-emitted electromagnetic emissions on a global scale.

  20. Helicopter Electromagnetic and Magnetic Survey Data and Maps, Seco Creek Area, Medina and Uvalade Counties, Texas

    USGS Publications Warehouse

    Smith, Bruce D.; Smith, David V.; Hill, Patricia L.; Labson, Victor F.

    2003-01-01

    A helicopter electromagnetic and magnetic (HEM) survey was completed of a 209 square kilometer (81 square miles) area of the central Edwards aquifer. This open-file report is a release of the airborne geophysical data and a summary of the hydrologic application. The survey area was centered on the Valdina Farms sinkhole along the Seco Creek drainage in western Medina County, Texas. Flight lines were flown north south with three east west tie lines to aid in leveling the magnetic data. Additional lines were flown on each side of the Seco and Little Seco Creek drainages. A five kilometer (4 mile) extension of 15 lines was flown north of the main survey block centered on Seco Creek. This digital data release contains the flight line data, grids, and maps of the HEM survey data. The Edwards aquifer in this area consists of three hydrologic zones: catchment, recharge, and confined. The Glen Rose Formation is exposed in the catchment area. The recharge zone is situated in the Balcones fault zone where the Devils River Group of the Edwards aquifer has been exposed by normal faults. The magnetic data is not discussed in depth here, but does have high amplitude closed anomalies caused by shallow igneous intrusives. The Woodard Cave Fault that separates the recharge and catchment zones is in places associated with a weak linear magnetic low. The HEM data has been processed to produce apparent resistivities for each of the six EM coil pairs and frequencies. Maps of the apparent resistivity for the five horizontal coil pairs show that the catchment, recharge, and confined zones all have numerous linear features that are likely caused by structures, many of which have not been mapped. The distribution of high resistivity areas reflects the lithologic differences within the Trinity and Edwards aquifers.

  1. 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.

  2. Aeromagnetic anomalies and discordant lineations beneath the Niger Delta - Implications for new fracture zones and multiple sea-floor spreading directions in the 'meso-Atlantic' Gulf of Guinea cul-de-sac

    NASA Astrophysics Data System (ADS)

    Babalola, Olufemi O.; Gipson, Mack, Jr.

    1991-06-01

    An aeromagnetic map eliminating data gaps in the Nigerian continental margin is presented, and the implications of the mapped fracture zone structure and the interpretation of two triple junctions beneath the Niger Delta Basin for its early tectonic history are discussed. Sea-floor spreading was found to occur in two different directions, and not only the well-documented NE-SW spreading in the 'meso-Atlantic' ocean. The existence of two triple junctions located where the Niger Delta Basin abuts the southern ends of the Abakaliki and Anambra troughs is shown. The two newly interpreted triple junctions beneath the Niger Delta demonstrate the previously recognized structural complexity of the region, necessitating a review of models for its early tectonic history.

  3. An aerial radiological survey of Project Gasbuggy and surrounding area, Rio Arriba County, New Mexico. Date of survey: October 27, 1994

    SciTech Connect

    1995-08-01

    An aerial radiological survey was conducted over the Project Gasbuggy site, 55 miles (89 kilometers) east of Farmington, New Mexico, on October 27, 1994. Parallel lines were flown at intervals of 300 feet (91 meters) over a 16-square-mile (41-square-kilometer) area at a 150-foot (46-meter) altitude centered on the Gasbuggy site. The gamma energy spectra obtained were reduced to an exposure rate contour map overlaid on a high altitude aerial photograph of the area. The terrestrial exposure rate varied from 14 to 20 {micro}R/h at 1 meter above ground level. No anomalous or man-made isotopes were found.

  4. Multicultural Survey.

    ERIC Educational Resources Information Center

    Renyi, Judith, Comp.

    In May of 1992, the Alliance for Curriculum Reform (ACR) surveyed member organizations and others who had participated in ACR activities concerning their printed policies on issues relating to multicultural education. The areas of interest for the survey were: printed policy(ies) on multicultural content/curriculum; printed policy(ies) on student…

  5. SURVEY INSTRUMENT

    DOEpatents

    Borkowski, C J

    1954-01-19

    This pulse-type survey instrument is suitable for readily detecting {alpha} particles in the presence of high {beta} and {gamma} backgrounds. The instruments may also be used to survey for neutrons, {beta} particles and {gamma} rays by employing suitably designed interchangeable probes and selecting an operating potential to correspond to the particular probe.

  6. Estimating Curie Point Depth and Heat Flow Map for Northern Red Sea Rift of Egypt and Its Surroundings, from Aeromagnetic Data

    NASA Astrophysics Data System (ADS)

    Saleh, Salah; Salk, Müjgan; Pamukçu, Oya

    2013-05-01

    In this study, we aim to map the Curie point depth surface for the northern Red Sea rift region and its surroundings based on the spectral analysis of aeromagnetic data. Spectral analysis technique was used to estimate the boundaries (top and bottom) of the magnetized crust. The Curie point depth (CPD) estimates of the Red Sea rift from 112 overlapping blocks vary from 5 to 20 km. The depths obtained for the bottom of the magnetized crust are assumed to correspond to Curie point depths where the magnetic layer loses its magnetization. Intermediate to deep Curie point depth anomalies (10-16 km) were observed in southern and central Sinai and the Gulf of Suez (intermediate heat flow) due to the uplifted basement rocks. The shallowest CPD of 5 km (associated with very high heat flow, ~235 mW m-2) is located at/around the axial trough of the Red Sea rift region especially at Brothers Island and Conrad Deep due to its association with both the concentration of rifting to the axial depression and the magmatic activity, whereas, beneath the Gulf of Aqaba, three Curie point depth anomalies belonging to three major basins vary from 10 km in the north to about 14 km in the south (with a mean heat flow of about 85 mW m-2). Moreover, low CPD anomalies (high heat flow) were also observed beneath some localities in the northern part of the Gulf of Suez at Hammam Fraun, at Esna city along River Nile, at west Ras Gharib in the eastern desert and at Safaga along the western shore line of the Red Sea rift. These resulted from deviatoric tensional stresses developing in the lithosphere which contribute to its further extension and may be due to the opening of the Gulf of Suez and/or the Red Sea rift. Furthermore, low CPD (with high heat flow anomaly) was observed in the eastern border of the study area, beneath northern Arabia, due to the quasi-vertical low-velocity anomaly which extends into the lower mantle and may be related to volcanism in northern Arabia. Dense microearthquakes

  7. Distribution of buried hydrothermal alteration deduced from high-resolution magnetic surveys in Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Bouligand, Claire; Glen, Jonathan M. G.; Blakely, Richard J.

    2014-04-01

    Yellowstone National Park (YNP) displays numerous and extensive hydrothermal features. Although hydrothermal alteration in YNP has been extensively studied, the volume, geometry, and type of rock alteration at depth remain poorly constrained. In this study, we use high-resolution airborne and ground magnetic surveys and measurements of remanent and induced magnetization of field and drill core samples to provide constraints on the geometry of hydrothermal alteration within the subsurface of three thermal areas in YNP (Firehole River, Smoke Jumper Hot Springs, and Norris Geyser Basin). We observe that hydrothermal zones from both liquid- and vapor-dominated systems coincide with magnetic lows observed in aeromagnetic surveys and with a decrease of the amplitude of short-wavelength anomalies seen in ground magnetic surveys. This suggests a strong demagnetization of both the shallow and deep substratum within these areas associated with the removal of magnetic minerals by hydrothermal alteration processes. Such demagnetization is confirmed by measurements of rock samples from hydrothermal areas which display significantly decreased total magnetization. A pronounced negative anomaly is observed over the Lone Star Geyser and suggests a significant demagnetization of the substratum associated with areas displaying large-scale fluid flow. The ground and airborne magnetic surveys are used to evaluate the distribution of magnetization in the subsurface. This study shows that significant demagnetization occurs over a thickness of at least a few hundred meters in hydrothermal areas at YNP and that the maximum degree or maximum thickness of demagnetization correlates closely with the location of hydrothermal activity and mapped alteration.

  8. An aerial radiological survey of Maralinga and EMU, South Australia

    SciTech Connect

    Tipton, W J; Berry, H A; Fritzsche, A E

    1988-10-01

    An aerial radiological survey was conducted over the former British nuclear test ranges at Maralinga and Emu in South Australia from May through July 1987. The survey covered an area of approximately 1,550 square kilometers which included the nine major trial sites, where a nuclear yield occurred, and all the minor trial sites, where physics experiments were conducted. Flight lines were flown at an altitude of 30 meters with line spacings of 50, 100, and 200 meters depending on the area and whether man-made contamination was present. Results of the aerial survey were processed for americium-241 (used to determine plutonium contamination), cesium-137, cobalt-60, and uranium-238. The aerial survey also detected the presence of europium-152, a soil activation product, in the immediate vicinity of the major trial ground zeros. Ground measurements were also made at approximately 120 locations using a high-resolution germanium detector to provide supplemental data for the aerial survey. This survey was conducted as part of a series of studies being conducted over a two to three-year timeframe to obtain information from which options and associated costs can be formulated about the decontamination and possible rehabilitation of the former nuclear test sites.

  9. Tectonic map of Liberia based on geophysical and geological surveys

    USGS Publications Warehouse

    Behrendt, John Charles; Wotorson, Cletus S.

    1972-01-01

    Interpretation of the results of aeromagnetic, total-gamma radioactivity, and gravity surveys combined with geologic data for Western Liberia from White and Leo (1969) and other geologic information allows the construction of a tectonic map of Liberia. The map approximately delineates the boundaries between the Liberian (ca. 2700 m.y.) province in the northwestern two-thirds of the country, the Eburnean (ca. 2000 m.y.) province in the south-eastern one-third, and the Pan-African (ca. 550 m.y.) province in the coastal area of the northwestern two-thirds of the country. Rock follation and tectonic structural features trend northeastward in the Liberian province, east-northeastward to north-northeastward in the Eburnean province, and northwestward in the Pan-African age province. Linear residual magnetic anomailes 20-80 km wide and 200-600 gammas in amplitude and following the northeast structural trend typical of the Liberian age province cross the entire country and extend into Sierra Leone and Ivory Coast.

  10. New York State Geological Survey crystalline rock project. Progress report

    SciTech Connect

    Not Available

    1985-03-01

    Presented is a preliminary geologic map of the West-Central Adirondack Region, based on mapping by members of the New York State Geological Survey and participants from several universities during the 1984 field season. The area mapped comprises portions of the West Canada Lakes, Old Forge, McKeever, Number Four, Big Moose and Raquette Lake 15 minute quadrangles. The geology of the area is dominated by two major groups of hornblende-granulite facies rocks: (a) a supracrustal sequence locally showing internal stratigraphy, including quartzofeldspathic leucogneiss, kinzigite, marble, calcsilicate granulite and amphibolite, and (b) granitic and charnockitic gneisses of both plutonic and supracrustal origin, which are widespread and often occur as elliptical domes and lenses, as well as being interstratified with the metasedimentary sequence. Clear intrusive relationships are few. In addition to these rocks, minor intrusions of meta-anorthosite and metagabbro are locally present. At least three phases of folding are present. The first is expressed by regional foliation development. The second generation is tight to isoclinal and overturned with axial trends ranging from east to northeast. The third generation is open folds with north to northwest axial trends. Good correlation exists between photogeology, aeromagnetics, and field observations.

  11. Surveying System

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Sunrise Geodetic Surveys are setting up their equipment for a town survey. Their equipment differs from conventional surveying systems that employ transit rod and chain to measure angles and distances. They are using ISTAC Inc.'s Model 2002 positioning system, which offers fast accurate surveying with exceptional signals from orbiting satellites. The special utility of the ISTAC Model 2002 is that it can provide positioning of the highest accuracy from Navstar PPS signals because it requires no knowledge of secret codes. It operates by comparing the frequency and time phase of a Navstar signal arriving at one ISTAC receiver with the reception of the same set of signals by another receiver. Data is computer processed and translated into three dimensional position data - latitude, longitude and elevation.

  12. Geosat survey

    NASA Astrophysics Data System (ADS)

    The Geosat Committee, a nonprofit, educational organization dedicated to improving satellite remote sensing for geological applications, is surveying the international geological community to determine the most important areas of the world for the exploration of nonrenewable resources. The results of this survey, whose sources will be kept confidential, will be given as recommendations for early satellite-scene selection to the the U.S. government (via the National Oceanic and Atmospheric Administration) and to other countries with satellites or ground receiving stations.

  13. Liquid Motion Experiment Flown on STS-84

    NASA Technical Reports Server (NTRS)

    Dalton, Penni J.

    1998-01-01

    During some part or all of each mission, about half of all scientific and commercial spacecraft will spin. For example, commercial spacecraft are made to spin during the transfer maneuver from low Earth orbit to the mission orbit to obtain gyroscopic stiffness. Many spacecraft spin continuously in orbit for the same reason. Other reasons for spinning include controlling the location of liquid propellants within their tanks and distributing solar heat loads. Although spinning has many benefits, it also creates problems because of the unavoidable wobble motion that accompanies spinning. Wobbling makes the spacecraft's flexible components oscillate. The energy dissipated by the internal friction of these components causes the wobbling amplitude to increase continually until, at some point, the attitude control thrusters must be fired to bring the spacecraft's amplitude back to an acceptable level.

  14. Radioactive 7Be materials flown on LDEF

    NASA Technical Reports Server (NTRS)

    Gregory, John C.

    1992-01-01

    Following the discovery of the atmospheric cosmogenic radionuclide Be-7 on the Long Duration Exposure Facility (LDEF), we began a search for other known nuclides produced by similar mechanisms. None of the others have the narrow gamma-ray line emission of Be-7 decay which enable its rapid detection and quantification. A search for Be-10 atoms on LDEF clamp plates using accelerator mass spectrometry is described. An unexpected result was obtained.

  15. Effects of spaceflight in the adductor longus muscle of rats flown in the Soviet Biosatellite COSMOS 2044. A study employing neural cell adhesion molecule (N-CAM) immunocytochemistry and conventional morphological techniques (light and electron microscopy)

    NASA Technical Reports Server (NTRS)

    D'Amelio, F.; Daunton, N. G.

    1992-01-01

    The effects of spaceflight upon the "slow" muscle adductor longus were examined in rats flown in the Soviet Biosatellite COSMOS 2044. The techniques employed included standard methods for light microscopy, neural cell adhesion molecule (N-CAM) immunocytochemistry and electron microscopy. Light microscopic observations revealed myofiber atrophy and segmental necrosis accompanied by cellular infiltrates composed of macrophages, leukocytes and mononuclear cells. Neural cell adhesion molecule immunoreactivity (N-CAM-IR) was seen on the myofiber surface and in regenerating myofibers. Ultrastructural alterations included Z band streaming, disorganization of myofibrillar architecture, sarcoplasmic degradation, extensive segmental necrosis with apparent preservation of the basement membrane, degenerative phenomena of the capillary endothelium and cellular invasion of necrotic areas. Regenerating myofibers were identified by the presence of increased amounts of ribosomal aggregates and chains of polyribosomes associated with myofilaments. The principal electron microscopic changes of the neuromuscular junctions showed axon terminals with a decrease or absence of synaptic vesicles replaced by microtubules and neurofilaments, degeneration of axon terminals, vacant axonal spaces and changes suggestive of axonal sprouting. The present observations suggest that alterations such as myofibrillar disruption and necrosis, muscle regeneration and denervation and synaptic remodeling at the level of the neuromuscular junction may take place during spaceflight.

  16. Airborne gamma-ray spectrometer and magnetometer survey: north/south tieline. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted along the 99/sup 0/ longitude meridian from the Canadian border southward to the Mexican border. A total of 1555 line miles of geophysical data were acquired and, subsequently, compiled. The north-south tieline was flown as part of the National Uranium Resources Evaluation. NURE is a program of the US Department of Energy's Grand Junction, Colorado, office to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  17. Integrated geophysical surveys for mapping lati-andesite intrusive bodies, Chino Valley, Arizona

    USGS Publications Warehouse

    El-Kaliouby, Hesham; Sternberg, Ben K.; Hoffmann, John P.; Langenheim, V.E.

    2012-01-01

    Three different geophysical methods (magnetic, transient electromagnetic (TEM) and gravity) were used near Chino Valley, Arizona, USA in order to map a suspected lati-andesite intrusive body (plug) previously located by interpretation of aeromagnetic data. The magnetic and TEM surveys provided the best indication of the location and depth of the plug. The north-south spatial extent of this plug was estimated to be approximately 600 meters. The depth to the top of the plug was found from the TEM survey to be approximately 350 meters near the center of the survey. The location of the plug defined by the ground magnetic data is consistent with that from the TEM data. Gravity data mostly image the basin-basement interface with a small contribution from the plug of about 0.5 mGal. Results from this investigation can be used to help define the irregular subsurface topography caused by several intrusive lati-andesite plugs that could influence groundwater flow in the area.

  18. Regional Geophysical Surveys and Crustal Structure of the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Rodríguez-Chavez, F.; Fucugauchi, J. U.

    2007-05-01

    Results of processing and modeling of anomaly data from regional geophysical surveys in the southern sector of the Gulf of Mexico are presented. The Gulf of Mexico has been intensively studied for several years, mainly because of the economic potential of the oil and gas resources. The basin may have formed by sea-floor spreading, rifting and lateral translation/rotation of continental slivers ssociated with major break-up and drifting apart of North and South America continental plates in the mid Mesozoic. Major structural features and crustal structure, including the continent-ocean transition and Gulf coastal passive margin are relatively poorly understood. Aerogeophysical gravity and magnetic surveys have been conducted and data are processed and modeled to investigate on the Gulf crustal structure. Spectral statistical estimates of regional basement depths derived from aeromagnetics give mean depths of 8000 m. Estimates derived from gravity anomalies are in the order of 10000 m. Depths derived from 2D and 3D seismic reflection surveys conducted for oil exploration purposes in selected areas indicate average depths to basement from 6000 m to values grater than those derived from potential field data.

  19. Airborne gamma-ray spectrometer and magnetometer survey, New Rockford Quadrangle, North Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the New Rockford map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1397 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  20. Airborne gamma-ray spectrometer and magnetometer survey, Mitchell Quadrangle, South Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the Mitchell map area. The purpose of this program is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1479 line miles are in this quadrangle.

  1. Airborne gamma-ray spectrometer and magnetometer survey: Huron quadrangle, South Dakota. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over eleven (11) 2/sup 0/ x 1/sup 0/ NTMS quadrangles located in the states of Minnesota and Wisconsin and seven (7) 2/sup 0/ x 1/sup 0/ NTMS quadrangles in North and South Dakota. The quadrangles located within the North and South Dakota survey area include Devil's Lake, New Rockford, Jamestown, Aberdeen, Huron, Mitchell, and Sioux Falls. This report discusses the results obtained over the Huron map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately twenty-four (24) miles apart. A total of 21,481 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1459 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  2. Airborne and field-temperature surveys compared at Long Valley KGRA, California

    SciTech Connect

    Del Grande, N.K.

    1981-06-01

    An airborne predawn radiometric temperature survey was flown over the Long Valley KGRA. Radiometric temperatures were recorded at 10 to 12 ..mu..m and 4.5 to 5.5 ..mu..m. They were corrected to obtain true land-surface temperatures in agreement with field data. After accounting for thermal effects from surface features, there remained a thermal anomaly. The anomalous zone encompassed 2 km/sup 2/. It was a dry land area with a predawn surface temperature which averaged 1.4 +- 0.3/sup 0/C warmer than ambient. This area coincided with a thermal discharge zone where deep temperature gradients were 5 to 30 times normal. The predawn radiometric survey clarified and supplemented conclusions drawn from 6 to 30m deep field surveys. Heat from hydrothermal discharge was stored in a shallow aquifer and conducted to the surface.

  3. Complexity Survey.

    ERIC Educational Resources Information Center

    Gordon, Sandra L.; Anderson, Beth C.

    To determine whether consensus existed among teachers about the complexity of common classroom materials, a survey was administered to 66 pre-service and in-service kindergarten and prekindergarten teachers. Participants were asked to rate 14 common classroom materials as simple, complex, or super-complex. Simple materials have one obvious part,…

  4. Airborne gamma-ray spectrometer and magnetometer survey: Susanville quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Susanville, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1642.8 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  5. Airborne gamma-ray spectrometer and magnetometer survey: Ukiah quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Ukiah, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1517 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  6. Airborne gamma-ray spectrometer and magnetometer survey: Chico quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Chico, California, map area. Traverse lines were flown in an east-west direction at a line spacing of three. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 3026.4 line miles are in the quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  7. Airborne gamma-ray spectrometer and magnetometer survey: Alturas quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Alturas, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1631.6 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  8. Airborne gamma-ray spectrometer and magnetometer survey, Medford Quadrangle Oregon. Final report

    SciTech Connect

    Not Available

    1981-04-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Medford, Oregon, map area. Traverse lines were flown in an east-west direction at a line spacing of three miles. Tie lines were flown north-south approximately twelve miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 2925 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  9. Airborne gamma-ray spectrometer and magnetometer survey, Roseburg Quadrangle, Oregon. Final report

    SciTech Connect

    Not Available

    1981-03-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Roseburg, Oregon, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were acquired, compiled, and interpreted during the survey, of which 1596 line miles are in this quadrangle. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  10. Airborne gamma-ray spectrometer and magnetometer survey: Eureka quadrangle, California. Final report

    SciTech Connect

    Not Available

    1981-05-01

    An airborne high sensitivity gamma-ray spectrometer and magnetometer survey was conducted over ten (10) areas over northern California and southwestern Oregon. These include the 2/sup 0/ x 1/sup 0/ NTMS quadrangles of Roseburg, Medford, Weed, Alturas, Redding, Susanville, Ukiah, and Chico along with the 1/sup 0/ x 2/sup 0/ areas of the Coos Bay quadrangle and the Crescent City/Eureka areas combined. This report discusses the results obtained over the Eureka/Crescent City, California, map area. Traverse lines were flown in an east-west direction at a line spacing of six (6) miles. Tie lines were flown north-south approximately eighteen (18) miles apart. A total of 16,880.5 line miles of geophysical data were aquired, compiled, and interpreted during the survey, of which 349.5 line miles are in this area. The purpose of this study is to acquire and compile geologic and other information with which to assess the magnitude and distribution of uranium resources and to determine areas favorable for the occurrence of uranium in the United States.

  11. On small satellites for oceanography: A survey

    NASA Astrophysics Data System (ADS)

    Guerra, André G. C.; Francisco, Frederico; Villate, Jaime; Aguado Agelet, Fernando; Bertolami, Orfeu; Rajan, Kanna

    2016-10-01

    The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano-satellites (with mass smaller than 100 kg and 2-3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.

  12. An Aerial Radiological Survey of Selected Areas of Area 18 - Nevada Test Site

    SciTech Connect

    Craig Lyons

    2009-07-31

    As part of the proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory-Nellis (RSL-Nellis) conducted an aerial radiological survey of selected areas of Area 18 of the Nevada Test Site (NTS) for the purpose of mapping man-made radiation deposited as a result of the Johnnie Boy and Little Feller I tests. The survey area centered over the Johnnie Boy ground zero but also included the ground zero and deposition area of the Little Feller I test, approximately 7,000 feet (2133 meters) southeast of the Johnnie Boy site. The survey was conducted in one flight. The completed survey covered a total of 4.0 square miles. The flight lines (with the turns) over the surveyed areas are presented in Figure 1. One 2.5-hour-long flight was performed at an altitude of 100 ft above ground level (AGL) with 200 foot flight-line spacing. A test-line flight was conducted near the Desert Rock Airstrip to ensure quality control of the data. The test line is not shown in Figure 1. However, Figure 1 does include the flight lines for a ''perimeter'' flight. The path traced by the helicopter flying over distinct roads within the survey area can be used to overlay the survey data on a base map or image. The flight survey lines were flown in an east-west orientation perpendicular to the deposition patterns for both sites. This technique provides better spatial resolution when contouring the data. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2-inch x 4-inch x 16-inch sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Data, in the form of gamma energy spectra, were collected every second over the course of the survey and were geo-referenced using a differential Global Positioning System. Spectral data allows the system to distinguish between ordinary fluctuations in natural background radiation levels and the signature produced by man

  13. Strain patterns deduced from high-resolution airborne surveys in Namibia

    NASA Astrophysics Data System (ADS)

    Ledru, P.; Garoeb, H.; Kamati, T.; Wackerle, R.; Martelet, G.; Truffert, C.

    2003-04-01

    High-resolution aeromagnetic dataset have been acquired in the framework of a long-term programme that aims at a complete coverage of Namibia in 2008. More than half of the territory has been already flown with a 200m line spacing and 2500m tie lines, at a terrain clearance of 80 to 100 m. The contribution of the interpretation of these datasets to the definition of the strain pattern is presented. The first test zone concerns an orogenic zone, the southern zone of the Damara belt, south of Rehoboth. The different maps of the gradients of the magnetic field reduced to the pole have been used in order to define the regional strain pattern. Following up a limited field work that has characterized the geometry and kinematics of the main discontinuities, it has been shown that this zone is characterized by one single orogenic phase marked by a reverse crustal-scale shear zone system (with a down-dip stretching direction) to which regional-scale NE-SW folding is related. The anastomosed shear zone system is thus traced along more than 200 km. A provisional foliation trajectory map can be drawn, transecting the bedding in the hinges of the folds within sediments and underlined by a magnetite-rich veinlet network within the pre-tectonic granites. Moreover, this strain pattern has been extended under the superficial deposits that cover the eastern half of the studied area. Automatic structural analysis has been performed using Geosoft and ArcView/SynArc. Thus, source edge detection, search of ridges and curvature analysis provide qualitative analysis while the search of discontinuities along the horizontal gradients of the magnetic field using SynArc produces a very satisfactory statistical approach of the structural pattern. A second test zone illustrates an extensional tectonic context, i.e. the northern termination of the NNE-SSW Mesozoic aborted rift, developed synchronously with the opening of the Southern Atlantic ocean at the Jurassic-Cretaceous boundary. A dense

  14. Laser Surveying

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NASA technology has produced a laser-aided system for surveying land boundaries in difficult terrain. It does the job more accurately than conventional methods, takes only one-third the time normally required, and is considerably less expensive. In surveying to mark property boundaries, the objective is to establish an accurate heading between two "corner" points. This is conventionally accomplished by erecting a "range pole" at one point and sighting it from the other point through an instrument called a theodolite. But how do you take a heading between two points which are not visible to each other, for instance, when tall trees, hills or other obstacles obstruct the line of sight? That was the problem confronting the U.S. Department of Agriculture's Forest Service. The Forest Service manages 187 million acres of land in 44 states and Puerto Rico. Unfortunately, National Forest System lands are not contiguous but intermingled in complex patterns with privately-owned land. In recent years much of the private land has been undergoing development for purposes ranging from timber harvesting to vacation resorts. There is a need for precise boundary definition so that both private owners and the Forest Service can manage their properties with confidence that they are not trespassing on the other's land.

  15. Farmland Survey

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A 1981 U.S. Department of Agriculture (USDA) study estimated that the nation is converting farmland to non-agricultural uses at the rate of 3 million acres a year. Seeking information on farmland loss in Florida, the state legislature, in 1984, directed establishment of a program for development of accurate data to enable intelligent legislation of state growth management. Thus was born Florida's massive Mapping and Monitoring of Agricultural Lands Project (MMALP). It employs data from the NASA-developed Landsat Earth resources survey satellite system as a quicker, less expensive alternative to ground surveying. The 3 year project involved inventory of Florida's 36 million acres classifying such as cropland, pastureland, citrus, woodlands, wetland, water and populated areas. Direction was assigned to Florida Department of Community Affairs (DCA) with assistance from the DOT. With the cooperation of the USDA, Soil Conservation Service, DCA decided that combining soil data with the Landsat land cover data would make available to land use planners a more comprehensive view of a county's land potential.

  16. Airborne and Ground Electrical Surveys for Subsurface Mapping of the Arbuckle Aquifer, Central Oklahoma

    NASA Astrophysics Data System (ADS)

    Smith, D.; Smith, B. D.; Blome, C. D.; Osborn, N.

    2008-12-01

    Airborne and ground electrical surveys have been conducted to map the subsurface hydrogeologic character of the Arbuckle-Simpson aquifer in south central Oklahoma. An understanding of the geologic framework and hydrogeologic characteristics is necessary to evaluate groundwater flow through the highly faulted, structurally complex, carbonate aquifer. Results from this research will further understanding of the aquifer and will assist in managing the water resources of the region. The major issues include water quality, the allocation of water rights, and the potential impacts of pumping on springs and stream. Four areas in the Hunton anticline area, with distinctly different geology, were flown with a frequency domain helicopter electromagnetic system (HEM) in March, 2007. Ground electrical studies include dc resistivity imaging and natural field audiomagnetotelluric (AMT), and magnetotelluric (MT) surveys. The HEM resistivity and total field magnetic survey was flown in four blocks, A through D, mostly with a line spacing of 400 m. Block A extends from the Chickasaw National Recreational Area (CHIC) to Mill Creek on the west side of the anticline. The surface geology of this block is mostly dolomitic limestone of the Arbuckle Group that is in fault contact with younger Paleozoic clastic rocks. The flight line spacing was 800 meters in the western half of the block and 400 meters in the eastern part. Airborne magnetic data indicate that the Sulphur fault bends south to merge with the Mill Creek fault which substantiates an earlier hypothesis first made from interpretation of gravity data. Block B, located on the north side of the anticline consists of mostly of Arbuckle and Simpson Group rocks. Block C, covering most of the Clarita horst on the east side of the anticline, consists of the Upper Ordovician to the Lower Pennsylvanian shales. Block D, which was flown to include a deep test well site at Spears ranch, consisted of eight lines spaced at 400 meters. The HEM

  17. Interpretations of magnetic anomalies at a potential repository site located in the Yucca Mountain area, Nevada Test Site

    SciTech Connect

    Bath, G.D.; Jahren, C.E.

    1984-12-31

    In the Yucca Mountain area near the southwestern border of the Nevada Test Site, studies of the relation of magnetic properties to geologic features have provided structural information at and near a potential site for storage or radioactive waste. Interpreted features include a tabular mass of magnetized sedimentary rock beneath thick deposits of volcanic rock, and 11 major faults that strike generally northward and displace magnetized volcanic rock. A positive anomaly in a high-altitude aeromagnetic survey over exposures of strongly magnetized argillite of the Eleana Formation extends westward 20 km into the site area where interpretations indicate an argillite thickness of 800 m at a depth of 2.25 km. The high magnetite content of the argillite is not typical of the region, and was probably introduced by the heating effects of an underlying pluton. The basis for mapping traces of faults, and identifying their upthrown sides, was developed elsewhere at Yucca fault in the relatively simple volcanic terrains of Yucca Flat. In the site area, analyses of aeromagnetic anomalies from a low-altitude east-west aeromagnetic survey show the Topopah Spring Member of the Paintbrush Tuff as the primary source of anomalies from faulted sequences of volcanic rock. Faults related to belts of positive and negative anomalies surrounding the site have been identified. The possibility that an east-west pattern of anomalies is related to structure crossing the site was investigated by a recent aeromagnetic survey flown at low altitude in north-south directions. A significant reduction in amplitude of these anomalies resulted when effects of the deeply buried argillite were removed. The remaining anomalies over the site can be explained by a change in lateral extent, or magnetic properties, of volcanic units beneath the Topopah Spring Member. 37 references, 22 figures, 1 table.

  18. Helicopter electromagnetic and magnetic geophysical survey data, portions of the North Platte and South Platte Natural Resources Districts, western Nebraska, May 2009

    USGS Publications Warehouse

    Smith, B.D.; Abraham, J.D.; Cannia, J.C.; Minsley, B.J.; Deszcz-Pan, M.; Ball, L.B.

    2010-01-01

    This report is a release of digital data from a helicopter electromagnetic and magnetic survey that was conducted during June 2009 in areas of western Nebraska as part of a joint hydrologic study by the North Platte Natural Resource District (NRD), South Platte NRD, and U.S. Geological Survey (USGS). Flight lines for the survey totaled 937 line kilometers (582 line miles). The objective of the contracted survey, conducted by Fugro Airborne, Ltd., is to improve the understanding of the relation between surface-water and groundwater systems critical to developing groundwater models used in management programs for water resources. A unique aspect of the survey is the flight line layout. One set of flight lines was flown in a zig-zag pattern extending along the length of the previously collected airborne data. The success of this survey design depended on a well-understood regional hydrogeologic framework and model developed by the Cooperative Hydrologic Study of the Platte River Basin and the airborne geophysical data collected in 2008. Resistivity variations along lines could be related to this framework. In addition to these lines, more traditional surveys consisting of parallel flight lines, separated by about 400 meters were carried out for three blocks in the North Platte NRD, the South Platte NRD and in the area of Crescent Lakes. These surveys helped to establish the spatial variations of the resistivity of hydrostratigraphic units. An additional survey was flown over the Crescent Lake area. The objective of this survey, funded by the USGS Office of Groundwater, was to map shallow hydrogeologic features of the southwestern part of the Sand Hills that contain a mix of fresh to saline lakes.

  19. Infrastructure Survey 2011

    ERIC Educational Resources Information Center

    Group of Eight (NJ1), 2012

    2012-01-01

    In 2011, the Group of Eight (Go8) conducted a survey on the state of its buildings and infrastructure. The survey is the third Go8 Infrastructure survey, with previous surveys being conducted in 2007 and 2009. The current survey updated some of the information collected in the previous surveys. It also collated data related to aspects of the…

  20. An aerial radiological survey of the Paducah Gaseous Diffusion Plant and surrounding area, Paducah, Kentucky

    SciTech Connect

    Not Available

    1992-11-01

    An aerial radiological survey of the Paducah Gaseous Diffusion Plant (PGDP) and surrounding area in Paducah, Kentucky, was conducted during May 15--25, 1990. The purpose of the survey was to measure and document the terrestrial radiological environment at the PGDP and surrounding area for use in effective environmental management and emergency response planning. The aerial survey was flown at an altitude of 61 meters (200 feet) along a series of parallel lines 107 meters (350 feet) apart. The survey encompassed an area of 62 square kilometers (24 square miles), bordered on the north by the Ohio River. The results of the aerial survey are reported as inferred exposure rates at 1 meter above ground level in the form of a gamma radiation contour map. Typical background exposure rates were found to vary from 5 to 12 microroentgens per hour ([mu]R/h). Protactinium-234m, a radioisotope indicative of uranium-238, was detected at several facilities at the PGDR. In support of the aerial survey, ground-based exposure rate and soil sample measurements were obtained at several sites within the survey perimeter. The results of the aerial and ground-based measurements were found to agree within [plus minus]15%.

  1. A large-scale integrated aerogeophysical survey of Afghanistan

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Childers, V. A.; Gardner, J. M.; Liang, R. T.; Bowles, J. H.; Abraham, J. D.

    2007-12-01

    A multi-sensor, multidisciplinary aerogeophysical survey of a major portion of Afghanistan was recently conducted by investigators from the Naval Research Laboratory and the U.S. Geological Survey. More than 110,000 line km of data tracks were flown aboard an NP-3D Orion aircraft. Sensor systems installed on the P-3 included dual gravimeters, scalar and vector magnetometers, a digital photogrammetric camera, a hyperspectral imager, and an L-band polarimetric synthetic aperture radar (SAR). Data from all sources were precisely co-registered to the ground by a combination of interferometric-mode Global Positioning System (GPS) and inertial measurements. The data from this integrated mapping mission support numerous basic and applied science efforts in Afghanistan including: resource assessment and exploration for oil, gas, and minerals, development of techniques for sensor fusion and automated analysis, and topics in crustal geophysics and geodesy. The data will also support civil infrastructure needs such as cadastral surveying, urban planning and development, and pipeline/powerline/road routing and construction, agriculture and hydrologic resource management, earthquake hazard analysis, and base-maps for humanitarian relief missions.

  2. Airborne Hyperspectral Survey of Afghanistan 2007: Flight Line Planning and HyMap Data Collection

    USGS Publications Warehouse

    Kokaly, Raymond F.; King, Trude V.V.; Livo, K. Eric

    2008-01-01

    Hyperspectral remote sensing data were acquired over Afghanistan with the HyMap imaging spectrometer (Cocks and others, 1998) operating on the WB-57 high altitude NASA research aircraft (http://jsc-aircraft-ops.jsc.nasa.gov/wb57/index.html). These data were acquired during the interval of August 22, 2007 to October 2, 2007, as part of the United States Geological Survey (USGS) project 'Oil and Gas Resources Assessment of the Katawaz and Helmand Basins'. A total of 218 flight lines of hyperspectral remote sensing data were collected over the country. This report describes the planning of the airborne survey and the flight lines that were flown. Included with this report are digital files of the nadir tracks of the flight lines, including a map of the labeled flight lines and corresponding vector shape files for geographic information systems (GIS).

  3. NURE aerial gamma-ray and magnetic-reconnaissance survey portions of New Mexico, Arizona, and Texas. Volume I. Instrumentation and data reduction. Final report

    SciTech Connect

    Not Available

    1981-09-01

    As part of the Department of Energy (DOE) National Uranium Resource Evaluation Program, a rotary-wing high sensitivity radiometric and magnetic survey was flown covering portions of the State of New Mexico, Arizona and Texas. The survey encompassed six 1:250,000 scale quadrangles, Holbrook, El Paso, Las Cruces, Carlsbad, Fort Sumner and Roswell. The survey was flown with a Sikorsky S58T helicopter equipped with a high sensitivity gamma ray spectrometer which was calibrated at the DOE calibration facilities at Walker Field in Grand Junction, Colorado, and the Dynamic Test Range at Lake Mead, Arizona. The radiometric data were processed to compensate for Compton scattering effects and altitude variations. The data were normalized to 400 feet terrain clearance. The reduced data is presented in the form of stacked profiles, standard deviation anomaly plots, histogram plots and microfiche listings. The results of the geologic interpretation of the radiometric data together with the profiles, anomaly maps and histograms are presented in the individual quadrangle reports. The survey was awarded to LKB Resources, Inc. which completed the data acquisition. In April, 1980 Carson Helicopters, Inc. and Carson Geoscience Company agreed to manage the project and complete delivery of this final report.

  4. The Italian national survey of aircrew exposure: II. On-board measurements and results.

    PubMed

    Curzio, G; Grillmaier, R E; O'Sullivan, D; Pelliccioni, M; Piermattei, S; Tommasino, L

    2001-01-01

    The Italian survey of aircrew exposure has been carried out with different advanced dosimetric systems, as described in part I of this paper. The key strategy of the survey was to obtain on-board comparison of measurements for both passive and real-time detectors flown together with passengers. The survey has been carried out in the period of solar minimum (1995-1997), in which the exposure to galactic cosmic rays reaches its maximum value. Even though carrying out the survey in the period of solar minimum was entirely coincidental, this circumstance has been used to good advantage to obtain a comprehensive set of data of the galactic cosmic radiation with little or no disturbance by the solar activity modulation. This comprehensive set of data covers flight routes between -20 degrees and 75 degrees geographic latitude at different civil aviation altitudes. The survey obtained with different advanced dosimetric systems has been supplemented by a large variety of data gathered with passive stacks on different short-range and long-range flights at supersonic and subsonic altitudes. Some of the most important conclusions which can be drawn from the survey are: (i) aircrew of civil aviation receive annual doses within the range of 1 mSv to 6 mSv; (ii) data from different periods of solar minimum agree well, since the discrepancies encountered seem mainly due to the different dosimetric systems used; (iii) repeated measurements on the same route are highly consistent.

  5. Airborne geophysical surveys conducted in western Nebraska, 2010: contractor reports and data

    USGS Publications Warehouse

    ,

    2014-01-01

    This report contains three contractor reports and data files for an airborne electromagnetic survey flown from June 28 to July 7, 2010. The first report; “SkyTEM Survey: Nebraska, USA, Data” describes data aquisition and processing from a time-domain electromagnetic and magnetic survey performed by SkyTEM Canada, Inc. (the North American SkyTEM subsidiary), in western Nebraska, USA. Digital data for this report are given in Appendix 1. The airborne geophysical data from the SkyTEM survey subsequently were processed and inverted by Aarhus Geophysics ApS, Aarhus, Denmark, to produce resistivity depth sections along each flight line. The result of that processing is described in two reports presented in Appendix 2, “Processing and inversion of SkyTEM data from USGS Area UTM–13” and “Processing and inversion of SkyTEM data from USGS Area UTM–14.” Funding for these surveys was provided by the North Platte Natural Resources District, the South Platte Natural Resources District, and the Twin Platte Natural Resources District, in Scottsbluff, Sidney, and North Platte, Nebraska, respectively. Any additional information concerning the geophysical data may be obtained from the U.S. Geological Survey Crustal Geophysics and Geochemistry Science Center, Denver Colorado.

  6. Regional TEMPEST survey in north-east Namibia

    NASA Astrophysics Data System (ADS)

    Peters, Geoffrey; Street, Gregory; Kahimise, Ivor; Hutchins, David

    2015-09-01

    A regional scale TEMPEST208 airborne electromagnetic survey was flown in north-east Namibia in 2011. With broad line spacing (4 km) and a relatively low-powered, fixed-wing system, the approach was intended to provide a regional geo-electric map of the area, rather than direct detection of potential mineral deposits. A key component of the geo-electric profiling was to map the relative thickness of the Kalahari sediments, which is up to 200 m thick and obscures most of the bedrock in the area. Knowledge of the thickness would allow explorers to better predict the costs of exploration under the Kalahari. An additional aim was to determine if bedrock conductors were detectable beneath the Kalahari cover. The system succeeded in measuring the Kalahari thickness where this cover was relatively thin and moderately conductive. Limitations in depth penetration mean that it is not possible to map the thickness in the centre of the survey area, and much of the northern half of the survey area. Additional problems arise due to the variable conductivity of the Kalahari cover. Where the conductivity of the Kalahari sediment is close to that of the basement, there is no discernable contrast to delineate the base of the Kalahari. Basement conductors are visible beneath the more thinly covered areas such as in the north-west and south of the survey area. The remainder of the survey area generally comprises deeper, more conductive cover and for the most part basement conductors cannot be detected. A qualitative comparison with VTEM data shows comparable results in terms of regional mapping, and suggests that even more powerful systems such as the VTEM may not detect discrete conductors beneath the thick conductive parts of the Kalahari cover.

  7. Remote sensing survey applied to synthetic geological mapping in Ivory Coast (West Africa)

    NASA Astrophysics Data System (ADS)

    Deroin, Jean-Paul; Delor, Claude; Simeon, Yves; Yao, Bertin

    1994-12-01

    We have used remote sensing as an additional method in 1:200 000-scale reconnaissance mapping of the Ivory Coast. Landsat imagery was chosen for its low cost, and its interest for relatively small-scale work and its synthetic and multispectral properties. This proved perfectly satisfactory, especially in the bush savanna to the north of latitude 7 deg 30'. The imagery was also compared with aeromagnetic survey results. The lithostructural features revealed by MSS can be directly correlated with field observations. 1) Certain clear facies variations (amphibolites or gabbros among acidic rocks, for example) are spectrally well expressed. Conglomerates are commonly distinctive (on the Katiola sheet for example), when they are sufficiently extensive and they form ridges that can be followed several tens of kilometres. 2) The traces of planar structures can, at least locally, be followed and correlated with a regional schistosity. Certain features mappable on images confirm offset across transcurrent structures identified on the ground (N-S transcurrent fault zones, for example). Our experience in Ivory Coast shows that the use of Landsat MSS imagery should systematically be considered for any small- scale studies in which only a small part of the budget can be attributed to remote sensing.

  8. Influence of gravity field uncertainties on the results from POGO and Magsat geomagnetic surveys

    NASA Technical Reports Server (NTRS)

    Taylor, P. T.; Langel, R. A.; Kahn, W. D.; Schanzle, A. F.; Jones, T. L.

    1981-01-01

    Errors in the gravity models used in satellite position calculations are examined as a possible source of the 0 to 100% variance found between POGO and Magsat magnetic data and the extrapolations of aerial magnetic survey data to satellite heights. For POGO data obtained over the New York Bight region using a relatively poor gravity field (a hybrid spherical harmonic model of degree 7 and order 6 with three higher order resonance terms), the magnitude of the error in the satellite height component is found to be sufficient to account for the amplitude of the discrepancy, however the frequency of the quasi-periodic orbital error is too large to explain the localized nature of the differences. For the case of the Magsat satellite, in which a more accurate gravity model was used, it is found that a 30 mgal gravitational anomaly distributed over a 5 x 5 deg area will produce insufficiently large position errors to account for the variations. The agreement between the two sets of satellite data in the New York Bight region suggests either a consistent error in satellite measurements, or problems with the reduction and processing of the aeromagnetic data.

  9. Robotic Surveying

    SciTech Connect

    Suzy Cantor-McKinney; Michael Kruzic

    2007-03-01

    -actuated functions to be controlled by an onboard computer. The computer-controlled Speedrower was developed at Carnegie Mellon University to automate agricultural harvesting. Harvesting tasks require the vehicle to cover a field using minimally overlapping rows at slow speeds in a similar manner to geophysical data acquisition. The Speedrower had demonstrated its ability to perform as it had already logged hundreds of acres of autonomous harvesting. This project is the first use of autonomous robotic technology on a large-scale for geophysical surveying.

  10. Alumni Perspectives Survey, 2010. Survey Report

    ERIC Educational Resources Information Center

    Sheikh, Sabeen

    2010-01-01

    During the months of April and September of 2009, the Graduate Management Admission Council[R] (GMAC[R]) conducted the Alumni Perspectives Survey, a longitudinal study of prior respondents to the Global Management Education Graduate Survey of management students nearing graduation. A total of 3,708 alumni responded to the April 2009 survey,…

  11. 2012 Alumni Perspectives Survey. Survey Report

    ERIC Educational Resources Information Center

    Leach, Laura

    2012-01-01

    Conducted in September 2011, this Alumni Perspectives Survey by the Graduate Management Admission Council (GMAC) is a longitudinal study of respondents to the Global Management Education Graduate Survey, the annual GMAC[R] exit survey of graduate management students in their final year of business school. This 12th annual report includes responses…

  12. List of publications of the N. C. Geological Survey

    SciTech Connect

    Not Available

    1986-01-01

    This booklet lists approximately 290 publications, some of which are out of print and may be borrowed from libraries and copied, but most listings include ordering information. The list contains bulletins, economic papers, regional geology series, field trip guidebooks, regional and county maps, geologic maps, orthophotoquads, topographic maps, aeromagnetic and aeroradiometric maps, etc.

  13. Community Perception Survey, 2001.

    ERIC Educational Resources Information Center

    Rasmussen, Patricia; Silverman, Barbara

    This document is a report on the 2001 Community Perception Survey administered by Mt. San Antonio College (SAC) (California). The survey gathered public perception data of SAC services and programs. The survey was mailed to 773 service area community leaders; 160 (21%) responded. Survey results showed that: (1) 70% had knowledge of SAC programs…

  14. ACSI Survey 2014

    Atmospheric Science Data Center

    2014-08-26

    Upcoming EOSDIS Survey   Dear Colleagues,   In the next few days, you will ... on behalf of NASA. This message will ask you to complete a survey for users of NASA Earth science data and services, which includes the ... System (EOSDIS) science data centers evaluated by this survey. The purpose of this survey is to help NASA and the DAACs assess ...

  15. Marine magnetic survey between Cabo da Roca and Cabo Espichel (near Lisbon, Portugal): first results

    NASA Astrophysics Data System (ADS)

    Neres, Marta; Terrinha, Pedro; Calado, António; Miranda, Miguel; Madureira, Pedro

    2016-04-01

    We present a magnetic survey conducted in the offshore region between Cabo da Roca and Sesimbra (mouth of Tagus River, Portugal). Strong magnetic anomalies are recognized in this area since a first marine survey in 1958 (Allan, 1965) and by further aeromagnetic survey (c.f. Silva et al, 2000). The anomalies have been linked to Cretaceous magmatic events related to the Upper Cretaceous Sintra magmatic complex and Lisbon volcanic complex, but their geometry and extension has yet not been resolved. The aim of the present survey was to unravel the location, geometry and type of the magnetic sources, thus contributing for the characterization of the main magmatic and tectonic features in the region. The survey was conducted in two legs (October 2014 and June 2015), consisting of 27 lines and 6 tielines, extending up to 40 km from the coast. The line spacing was 1 mile for the main lines and 5-6 miles for the tielines. The bathymetry of the surveyed area varies from very shallow (about 10 m) to near 3000 m. Total field was measured with a G-882 Cesium marine magnetometer of Geometrics (self-oscillating split-beam Cesium vapor), with frequency of acquisition of 10 Hz. Layback was real-time corrected using the acquisition software. Noise was removed by despike in Magpick software (Geometrics), and further processing was done using Oasis montaj (Geosoft) software. Data were subtracted of IGRF values and levelled by tielines to retrieve the final map of anomalies. Several punctual and linear anomalies with varying amplitude and wavenumber were identified, which cannot be explained by bathymetric variation; therefore they must then be due to the presence of higher susceptibility, likely volcanic rocks, and to structural inheritance associated with rifting and Alpine orogeny. The highest anomaly corresponds to the Cabo Raso positive magnetic anomaly, with maximum and minimum of 2800 nT and -1350 nT, respectively. This anomaly, already surveyed in 1958, has been compared to a

  16. Helicopter electromagnetic and magnetic geophysical survey data, Swedeburg and Sprague study areas, eastern Nebraska, May 2009

    USGS Publications Warehouse

    Smith, B.D.; Abraham, J.D.; Cannia, J.C.; Minsley, B.J.; Ball, L.B.; Steele, G.V.; Deszcz-Pan, M.

    2011-01-01

    This report is a release of digital data from a helicopter electromagnetic and magnetic survey conducted by Fugro Airborne Surveys in areas of eastern Nebraska as part of a joint hydrologic study by the Lower Platte North and Lower Platte South Natural Resources Districts, and the U.S. Geological Survey. The survey flight lines covered 1,418.6 line km (882 line mile). The survey was flown from April 22 to May 2, 2009. The objective of the contracted survey was to improve the understanding of the relation between surface water and groundwater systems critical to developing groundwater models used in management programs for water resources. The electromagnetic equipment consisted of six different coil-pair orientations that measured resistivity at separate frequencies from about 400 hertz to about 140,000 hertz. The electromagnetic data were converted to georeferenced electrical resistivity grids and maps for each frequency that represent different approximate depths of investigation for each survey area. The electrical resistivity data were input into a numerical inversion to estimate resistivity variations with depth. In addition to the electromagnetic data, total field magnetic data and digital elevation data were collected. Data released in this report consist of flight line data, digital grids, digital databases of the inverted electrical resistivity with depth, and digital maps of the apparent resistivity and total magnetic field. The range of subsurface investigation is comparable to the depth of shallow aquifers. The survey areas, Swedeburg and Sprague, were chosen based on results from test flights in 2007 in eastern Nebraska and needs of local water managers. The geophysical and hydrologic information from U.S. Geological Survey studies are being used by resource managers to develop groundwater resource plans for the area.

  17. The AAS Workforce Survey

    NASA Astrophysics Data System (ADS)

    Postman, Marc; Norman, D. J.; Evans, N. R.; Ivie, R.

    2014-01-01

    The AAS Demographics Committee, on behalf of the AAS, was tasked with initiating a biennial survey to improve the Society's ability to serve its members and to inform the community about changes in the community's demographics. A survey, based in part on similar surveys for other scientific societies, was developed in the summer of 2012 and was publicly launched in January 2013. The survey randomly targeted 2500 astronomers who are members of the AAS. The survey was closed 4 months later (April 2013). The response rate was excellent - 63% (1583 people) completed the survey. I will summarize the results from this survey, highlighting key results and plans for their broad dissemination.

  18. Total ozone derived from UV spectrophotometer measurements on the NASA CV-990 aircraft for the fall 1976 latitude survey flights

    NASA Technical Reports Server (NTRS)

    Hanser, F. A.

    1977-01-01

    An ultraviolet interference filter spectrophotometer was modified to use a photodiode and was flown on latitude survey flights in the fall of 1976. Comparison with Dobson station total ozone values shows agreement between UVS and Dobson total ozone of + or - 2 percent. The procedure used to convert UVS measured ozone above the aircraft altitude to total ozone above ground level introduces an additional 2 percent deviation for very high altitude UVS ozone data. Under stable aircraft operating conditions, the UVS derived ozone values have a variability, or reproducibility, of better than + or -1 percent. The UVS data from the latitude survey flights yield a detailed latitude profile of total ozone over the Pacific Ocean during November 1976. Significant latitudinal structure in total ozone is found at the middle latitudes (30 deg to 40 deg N and S).

  19. Merging high resolution geophysical and geochemical surveys to reduce exploration risk at glass buttes, Oregon

    SciTech Connect

    Walsh, Patrick; Fercho, Steven; Perkin, Doug; Martini, Brigette; Boshmann, Darrick

    2015-06-01

    The engineering and studies phase of the Glass Buttes project was aimed at reducing risk during the early stages of geothermal project development. The project’s inclusion of high resolution geophysical and geochemical surveys allowed Ormat to evaluate the value of these surveys both independently and in combination to quantify the most valuable course of action for exploration in an area where structure, permeability, and temperature are the most pressing questions. The sizes of the thermal anomalies at Glass Buttes are unusually large. Over the course of Phase I Ormat acquired high resolution LIDAR data to accurately map fault manifestations at the surface and collected detailed gravity and aeromagnetic surveys to map subsurface structural features. In addition, Ormat collected airborne hyperspectral data to assist with mapping the rock petrology and mineral alteration assemblages along Glass Buttes faults and magnetotelluric (MT) survey to try to better constrain the structures at depth. Direct and indirect identification of alteration assemblages reveal not only the geochemical character and temperature of the causative hydrothermal fluids but can also constrain areas of upflow along specific fault segments. All five datasets were merged along with subsurface lithologies and temperatures to predict the most likely locations for high permeability and hot fluids. The Glass Buttes temperature anomalies include 2 areas, totaling 60 km2 (23 mi2) of measured temperature gradients over 165° C/km (10° F/100ft). The Midnight Point temperature anomaly includes the Strat-1 well with 90°C (194 °F) at 603 m (1981 ft) with a 164 °C/km (10°F/100ft) temperature gradient at bottom hole and the GB-18 well with 71°C (160 °F) at 396 m (1300 ft) with a 182°C/km (11°F/100ft) gradient. The primary area of alteration and elevated temperature occurs near major fault intersections associated with Brothers Fault Zone and Basin and Range systems. Evidence for faulting is

  20. Geophysical and Geologic Training of the Afghan Geological Survey, May, 2008

    NASA Astrophysics Data System (ADS)

    Mooney, W. D.; Bohannon, R.; Abraham, J.; Medlin, J.

    2008-12-01

    Afghanistan lies within the Alpine-Himalayan orogeny, and consists of four primary tectonic units: (1) the North Afghan Platform, part of the greater Kazakhstan craton that includes Turkmenistan and Uzbekistan; (2) the mountainous Hindu Kush-Pamirs in the northeast; (3) the transpressional plate boundary at the Chaman fault near the border with Pakistan; and (4) the southern accreted terranes located south of the east-west oriented Herat fault. The diverse geology of Afghanistan affords the country abundant natural resources, as well as many natural hazards. In order to assist in the identification of these resources and to map hazardous faults, a multi-agency consortium including the Afghan Ministry of Mines and Industry, the USGS and the US Navel Research Lab conducted a detailed airborne geophysical survey of the western half of Afghanistan during 2007. Over 110,000 km of data were collected, including aeromagnetic, gravity, hyperspectral imagery, synthetic aperture radar and photogrammetric data. These data provide remarkable images of the surficial and sub-surface structure of the country. Armed with these new, high quality data, USGS trainers conducted an in-depth training course at the offices of the Afghan Geological Survey (AGS) during May, 2008. Eighty staff members of the AGS attended the four-day course which covered the following topics: (1) the geology and tectonics of Afghanistan; (2) a synthesis of modern plate tectonic processes; (3) use of geophysical and geological data to identify natural resources and hazardous faults. Particular emphasis was placed on oil and gas, mineral, coal and water resources. Earthquake and landslide hazards in Afghanistan were also discussed in detail. The building of scientific and technical capabilities at the AGS is a high priority because the development of their natural resources will have a positive impact on economic growth in Afghanistan. Future courses will benefit from hands-on training in methods of

  1. Corporate Recruiters Survey, 2011. Survey Report

    ERIC Educational Resources Information Center

    Edgington, Rachel

    2011-01-01

    In this report, the Graduate Management Admission Council[R] (GMAC[R]) presents the results from the 2011 Corporate Recruiters Survey. Conducted annually since 2001, this survey examines the job outlook for recent graduate business students as well as employer needs and expectations. The objectives of this study are to obtain a picture of the…

  2. 2012 Corporate Recruiters Survey. Survey Report

    ERIC Educational Resources Information Center

    Estrada, Rebecca

    2012-01-01

    This paper presents the results from the 2012 Corporate Recruiters Survey conducted by the Graduate Management Admission Council[R] (GMAC[R]). Conducted annually since 2001, this survey examines the job outlook for recent graduate business students as well as employer needs and expectations. The objectives of this study are to obtain a picture of…

  3. High resolution survey for topographic surveying

    NASA Astrophysics Data System (ADS)

    Luh, L. C.; Setan, H.; Majid, Z.; Chong, A. K.; Tan, Z.

    2014-02-01

    In this decade, terrestrial laser scanner (TLS) is getting popular in many fields such as reconstruction, monitoring, surveying, as-built of facilities, archaeology, and topographic surveying. This is due the high speed in data collection which is about 50,000 to 1,000,000 three-dimensional (3D) points per second at high accuracy. The main advantage of 3D representation for the data is that it is more approximate to the real world. Therefore, the aim of this paper is to show the use of High-Definition Surveying (HDS), also known as 3D laser scanning for topographic survey. This research investigates the effectiveness of using terrestrial laser scanning system for topographic survey by carrying out field test in Universiti Teknologi Malaysia (UTM), Skudai, Johor. The 3D laser scanner used in this study is a Leica ScanStation C10. Data acquisition was carried out by applying the traversing method. In this study, the result for the topographic survey is under 1st class survey. At the completion of this study, a standard of procedure was proposed for topographic data acquisition using laser scanning systems. This proposed procedure serves as a guideline for users who wish to utilize laser scanning system in topographic survey fully.

  4. Aerial radiation surveys

    SciTech Connect

    Jobst, J.

    1980-01-01

    A recent aerial radiation survey of the surroundings of the Vitro mill in Salt Lake City shows that uranium mill tailings have been removed to many locations outside their original boundary. To date, 52 remote sites have been discovered within a 100 square kilometer aerial survey perimeter surrounding the mill; 9 of these were discovered with the recent aerial survey map. Five additional sites, also discovered by aerial survey, contained uranium ore, milling equipment, or radioactive slag. Because of the success of this survey, plans are being made to extend the aerial survey program to other parts of the Salt Lake valley where diversions of Vitro tailings are also known to exist.

  5. Recovery and reprocessing of legacy geophysical data from the archives of the State Company of Geology and Mining (GEOSURV) of Iraq and Iraq Petroleum Company (IPC)

    USGS Publications Warehouse

    Smith, D.V.; Drenth, B.R.; Fairhead, J.D.; Lei, K.; Dark, J.A.; Al-Bassam, K.

    2011-01-01

    Aeromagnetic data belonging to the State Company of Geology and Mining of Iraq (GEOSURV) have been recovered from magnetic tapes and early paper maps. In 1974 a national airborne survey was flown by the French firm Compagnie General de Geophysique (CGG). Following the survey the magnetic data were stored on magnetic tapes within an air conditioned archive run by GEOSURV. In 1990, the power supply to the archive was cut resulting in the present-day poor condition of the tapes. Frontier Processing Company and the U.S. Geological Survey (USGS) have been able to recover over 99 percent of the original digital data from the CGG tapes. Preliminary reprocessing of the data yielded a total magnetic field anomaly map that reveals fine structures not evident in available published maps. Successful restoration of these comprehensive, high quality digital datasets obviates the need to resurvey the entire country, thereby saving considerable time and money. These data were delivered to GEOSURV in a standard format for further analysis and interpretation. A parallel effort by GETECH concentrated on recovering the legacy gravity data from the original field data sheets archived by IPC (Iraq Petroleum Company). These data have been compiled with more recent GEOSURV sponsored surveys thus allowing for the first time a comprehensive digital and unified national gravity database to be constructed with full principal facts. Figure 1 shows the final aeromagnetic and gravity data coverage of Iraq. The only part of Iraq lacking gravity and aeromagnetic data coverage is the mountainous areas of the Kurdish region of northeastern Iraq. Joint interpretation of the magnetic and gravity data will help guide future geophysical investigations by GEOSURV, whose ultimate aim is to discover economical mineral and energy resources. ?? 2011 Society of Exploration Geophysicists.

  6. Helicopter electromagnetic and magnetic geophysical survey data, Hunton anticline, south-central Oklahoma

    USGS Publications Warehouse

    Smith, Bruce D.; Smith, David V.; Deszcz-Pan, Maryla; Blome, Charles D.; Hill, Patricia

    2011-01-01

    This report is a digital data release for multiple geophysical surveys conducted in the Hunton anticline area of south-central Oklahoma. The helicopter electromagnetic and magnetic surveys were flown on March 16–17, 2007, in four areas of the Hunton anticline in south-central Oklahoma. The objective of this project is to improve the understanding of the geohydrologic framework of the Arbuckle-Simpson aquifer. The electromagnetic sensor for the helicopter electromagnetic survey consisted of six different transmitter-receiver orientations that measured the earth's electrical response at six distinct frequencies from approximately 500 Hertz to approximately 115,000 Hertz. The electromagnetic measurements were converted to electrical resistivity values, which were gridded and plotted on georeferenced maps. The map from each frequency represents a different depth of investigation for each area. The range of subsurface investigation is comparable to the depth of shallow groundwater. The four areas selected for the helicopter electromagnetic study, blocks A–D, have different geologic and hydrologic settings. Geophysical and hydrologic information from U.S. Geological Survey studies are being used by modelers and resource managers to develop groundwater resource plans for the Arbuckle-Simpson aquifer.

  7. Water Use: A Survey

    ERIC Educational Resources Information Center

    Fleming, Rose Glee; Warden, Jessie

    1976-01-01

    A survey of Florida State University students showed that their current laundry practices generate energy and water over-consumption. The survey also resulted in some concrete suggestions to the students that would improve their conservation practices. (Author/BP)

  8. National Health Care Survey

    Cancer.gov

    This survey encompasses a family of health care provider surveys, including information about the facilities that supply health care, the services rendered, and the characteristics of the patients served.

  9. New aerogeophysical survey targets crustal architecture and tectonic evolution of East Antarctica in the Recovery frontier

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.; Forsberg, R.; Jordan, T. A.; Matsuoka, K.; Olesen, A. V.; Ghidella, M. E.

    2013-12-01

    East Antarctica is the size of the conterminous US; it represents the least known continent on Earth despite being regarded as a keystone in Gondwana, Rodinia and possibly even earlier Columbia/Nuna supercontinents. Significant progress has however been made in recent years in the exploration of East Antarctica using airborne geophysical techniques. Spurred by the International Polar Year major collaborative international aerogeophysical campaigns have been performed over the Wilkes Subglacial Basin, the Aurora Subglacial Basin and the Gamburtsev Mountains in recent years, and these are continuing to provide fundamental new glimpses into the crustal architecture in interior East Antarctica, as well as several new interpretations regarding its linkages with tectonic and geodynamic evolution from Precambrian to Mesozoic/Cenozoic times. Here we present the first results of a major reconnaissance aerogeophysical survey over the largely unexplored Recovery ice stream catchment in East Antarctica completed during the IceGRAV 2012-13 field campaign, as part of an international Danish, Norwegian, UK and Argentine collaboration. Over 29,000 line km of new radio-echo sounding, laser altimetry, gravity and magnetic data were acquired using a British Antarctic Survey Twin Otter that surveyed the region. We focus primarily on the new potential field datasets for the area. Specifically, we present the first aeromagnetic anomaly maps, free air and Bouguer and isostatic residual maps obtained for the region. These images provide new geophysical perspectives that are required in order to address a cascade of open questions over this region. Where are the major tectonic boundaries between the Coats Land Block, the Shackleton Range, and the collage of different provinces recently proposed from aeromagnetic studies in Dronning Maud Land (Mieth and Jokat, 2013, GR)? Is the Coats Land crustal block a tectonic tracer for Laurentia (Loewy et al., 2011, Geology), and how and when was this

  10. Telephone Survey Designs.

    ERIC Educational Resources Information Center

    Casady, Robert J.

    The concepts, definitions, and notation that have evolved with the development of telephone survey design methodology are discussed and presented as a unified structure. This structure is then applied to some of the more well-known telephone survey designs and alternative designs are developed. The relative merits of the different survey designs…

  11. AECT Needs Survey, 2000.

    ERIC Educational Resources Information Center

    Frick, Theodore W.; Richter, Kurt; Kim, Minhee; Yang, Jessica Chao-I; Duvenci, Abdullah

    The purpose of this study was to determine the needs of AECT (Association for Educational Communications and Technology) members. A total of 590 individuals completed a Web-based 16-question survey after receiving an e-mail invitation from AECT. This survey was active between October 30 and November 10, 2000. The survey was categorized into three…

  12. Sensitive Questions in Surveys

    ERIC Educational Resources Information Center

    Tourangeau, Roger; Yan, Ting

    2007-01-01

    Psychologists have worried about the distortions introduced into standardized personality measures by social desirability bias. Survey researchers have had similar concerns about the accuracy of survey reports about such topics as illicit drug use, abortion, and sexual behavior. The article reviews the research done by survey methodologists on…

  13. Using data of gradient magnetic surveys at altitudes of 20-40 km for the analysis of map errors and models of the geomagnetic field

    NASA Astrophysics Data System (ADS)

    Brekhov, Oleg; Tsvetkov, Yury

    2016-07-01

    Gradient geomagnetic survey at altitudes of 20-40 km from the board of stratospheric balloon have a high degree of accuracy. The data of the geomagnetic field (GMF), obtained with the help of high-precision proton magnetometer and GPS navigation receivers, are considered as a benchmark for the analysis of geomagnetic data. Gradient magnetic data is obtained by us on the balloon, allowed us to estimate the quality of the analytical models of International Geomagnetic Referent Field (IGRF) and to identify the causes of anomalous GMF map errors. Research data of magnetic anomalies map for the study area on the route length of 900 km showed that their spectrum has no harmonics with a wavelength more 130 km. This is a significant defect in a ground map. Defects of magnetic anomalies map are explained by the poor quality of the main GMF and low altitude aeromagnetic survey, as well as the presence of intense local magnetic anomalies, which does not allow reliable identifying the background of weak magnetic fields of deep sources. Using a balloon and satellite magnetic data allows creating an adequate model of the geomagnetic field up to 720.

  14. US west coast revisited: An aeromagnetic perspective

    SciTech Connect

    Zietz, I.; Johnson, P.R. ); Bond, K.R. )

    1990-04-01

    A new compilation of magnetic data for the western conterminous United States and offshore areas provides significant information about crustal units and structures in the region. Features shown on the compilation include a magnetic quiet zone along the coast and two lineaments inland. The magnetic quiet zone correlates with the accretionary prism at the western edge of the North American plate and overlies subducted ocean crust; abrupt termination of ocean-floor magnetic anomalies at, or a short distance east of, the toe of the accretionary prism is an inferred effect subduction-induced low-temperature metamorphism of the ocean crust. The Puget Lowlands-San Joaquin lineament is an alignment of high-intensity magnetic anomalies that in the south, and possibly also in the north, are cause by bodies of mafic-ultramafic rocks accreted to North America during the Mesozoic and Tertiary. The lineup of the highs and the inferred lineup of the causative bodies may reflect fundamental structures that control Mesozoic and Tertiary evolution of the continental margin. The Mojave Desert lineament, a distinctive chain of short-wavelength magnetic anomalies in southern California, coincides partly with a zone of Mesozoic intrusions and the Cenozoic San Andreas fault system, but is likely to be older than both in origin and may reflect a Mesozoic or older crustal discontinuity.

  15. [Surveying a zoological facility through satellite-based geodesy].

    PubMed

    Böer, M; Thien, W; Tölke, D

    2000-06-01

    In the course of a thesis submitted for a diploma degree within the Fachhochschule Oldenburg the Serengeti Safaripark was surveyed in autumn and winter 1996/97 laying in the planning foundations for the application for licences from the controlling authorities. Taking into consideration the special way of keeping animals in the Serengeti Safaripark (game ranching, spacious walk-through-facilities) the intention was to employ the outstanding satellite based geodesy. This technology relies on special aerials receiving signals from 24 satellites which circle around the globe. These data are being gathered and examined. This examination produces the exact position of this aerial in a system of coordinates which allows depicting this point on a map. This procedure was used stationary (from a strictly defined point) as well as in the movement (in a moving car). Additionally conventional procedures were used when the satellite based geodesy came to its limits. Finally a detailed map of the Serengeti Safaripark was created which shows the position and size of stables and enclosures as well as wood and water areas and the sectors of the leisure park. Furthermore the established areas of the enclosures together with an already existing animal databank have flown into an information system with the help of which the stock of animals can be managed enclosure-orientated.

  16. Processing challenges in the XMM-Newton slew survey

    NASA Astrophysics Data System (ADS)

    Saxton, Richard D.; Altieri, Bruno; Read, Andrew M.; Freyberg, Michael J.; Esquej, M. P.; Bermejo, Diego

    2005-08-01

    The great collecting area of the mirrors coupled with the high quantum efficiency of the EPIC detectors have made XMM-Newton the most sensitive X-ray observatory flown to date. This is particularly evident during slew exposures which, while giving only 15 seconds of on-source time, actually constitute a 2-10 keV survey ten times deeper than current "all-sky" catalogues. Here we report on progress towards making a catalogue of slew detections constructed from the full, 0.2-12 keV energy band and discuss the challenges associated with processing the slew data. The fast (90 degrees per hour) slew speed results in images which are smeared, by different amounts depending on the readout mode, effectively changing the form of the point spread function. The extremely low background in slew images changes the optimum source searching criteria such that searching a single image using the full energy band is seen to be more sensitive than splitting the data into discrete energy bands. False detections due to optical loading by bright stars, the wings of the PSF in very bright sources and single-frame detector flashes are considered and techniques for identifying and removing these spurious sources from the final catalogue are outlined. Finally, the attitude reconstruction of the satellite during the slewing maneuver is complex. We discuss the implications of this on the positional accuracy of the catalogue.

  17. An Aerial Radiological Survey of the Las Vegas Strip and Adjacent Areas

    SciTech Connect

    Wasiolek, Piotr

    2009-02-01

    As proficiency training for the Radiological Mapping mission of the Aerial Measuring System (AMS), a survey team from the Remote Sensing Laboratory–Nellis (RSL-Nellis) conducted an aerial radiological survey of the Las Vegas Strip and adjacent areas on December 29, 2008. This survey was one of the bi-annual surveys carried in support of the city of Las Vegas Police Department (LVPD) before significant events on the Las Vegas Strip: e.g., the annual New Year’s Eve and July Fourth celebrations. The AMS operation and appropriate law enforcement agencies selected this area as an appropriate urban location to exercise AMS capability for mapping environmental radiation and searching for man-made radioactive sources. The surveys covered approximately 11 square miles. Each survey required a 2.5-hour-long flight, performed at an altitude of 300 ft above ground level (AGL) at a line spacing of 600 ft. Water line and test line flights are conducted over the Lake Mead and Government Wash areas to determine the non-terrestrial background contributed by aircraft, radon, and cosmic activity, and to determine the altitude-dependent air mass correction. The data were collected by the AMS data acquisition system (REDAR V) using an array of twelve 2" x 4" x 16" sodium iodide (NaI) detectors flown on-board a twin-engine Bell 412 helicopter. Gamma energy spectral data were collected second-by-second over the survey area. This spectral data allows the system to distinguish between natural terrestrial background contributions and man-made radioisotope contributions. Spectral data can also be used to identify specific man-made radioactive isotopes. Data geo-locations were determined with a Real-Time Differential Global Positioning System (RDGPS).

  18. Environmental Survey preliminary report

    SciTech Connect

    Not Available

    1988-04-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.

  19. Developing the online survey.

    PubMed

    Gordon, Jeffry S; McNew, Ryan

    2008-12-01

    Institutions of higher education are now using Internet-based technology tools to conduct surveys for data collection. Research shows that the type and quality of responses one receives with online surveys are comparable with what one receives in paper-based surveys. Data collection can take place on Web-based surveys, e-mail-based surveys, and personal digital assistants/Smartphone devices. Web surveys can be subscription templates, software packages installed on one's own server, or created from scratch using Web programming development tools. All of these approaches have their advantages and disadvantages. The survey owner must make informed decisions as to the right technology to implement. The correct choice can save hours of work in sorting, organizing, and analyzing data.

  20. An Aerial Radiological Survey of the Yucca Mountain Project Proposed Land Withdrawal and Adjacent Areas

    SciTech Connect

    Craig Lyons, Thane Hendricks

    2006-07-01

    An aerial radiological survey of the Yucca Mountain Project (YMP) proposed land withdrawal was conducted from January to April 2006, and encompassed a total area of approximately 284 square miles (73,556 hectares). The aerial radiological survey was conducted to provide a sound technical basis and rigorous statistical approach for determining the potential presence of radiological contaminants in the Yucca Mountain proposed Land withdrawal area. The survey site included land areas currently managed by the Bureau of Land Management, the U.S. Air Force as part of the Nevada Test and Training Range or the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) as part of the Nevada Test Site (NTS). The survey was flown at an approximate ground speed of 70 knots (36 meters per second), at a nominal altitude of 150 ft (46 m) above ground level, along a set of parallel flight lines spaced 250 ft (76 m) apart. The flight lines were oriented in a north-south trajectory. The survey was conducted by the DOE NNSA/NSO Remote Sensing Laboratory-Nellis, which is located in Las Vegas, Nevada. The aerial survey was conducted at the request of the DOE Office of Civilian Radioactive Waste Management. The primary contaminant of concern was identified by YMP personnel as cesium-137 ({sup 137}Cs). Due to the proposed land withdrawal area's proximity to the historical Nuclear Rocket Development Station (NRDS) facilities located on the NTS, the aerial survey system required sufficient sensitivity to discriminate between dispersed but elevated {sup 137}Cs levels from those normally encountered from worldwide fallout. As part of that process, the survey also measured and mapped the exposure-rate levels that currently existed within the survey area. The inferred aerial exposure rates of the natural terrestrial background radiation varied from less than 3 to 22 microroentgens per hour. This range of exposure rates was primarily due to the

  1. ESO imaging survey: infrared deep public survey

    NASA Astrophysics Data System (ADS)

    Olsen, L. F.; Miralles, J.-M.; da Costa, L.; Madejsky, R.; Jørgensen, H. E.; Mignano, A.; Arnouts, S.; Benoist, C.; Dietrich, J. P.; Slijkhuis, R.; Zaggia, S.

    2006-09-01

    This paper is part of the series presenting the final results obtained by the ESO Imaging Survey (EIS) project. It presents new J and Ks data obtained from observations conducted at the ESO 3.5 m New Technology Telescope (NTT) using the SOFI camera. These data were taken as part of the Deep Public Survey (DPS) carried out by the ESO Imaging Survey program, significantly extending the earlier optical/infrared EIS-DEEP survey presented in a previous paper of this series. The DPS-IR survey comprises two observing strategies: shallow Ks observations providing nearly full coverage of pointings with complementary multi-band (in general {UBVRI}) optical data obtained using ESO's wide-field imager (WFI) and deeper J and Ks observations of the central parts of these fields. Currently, the DPS-IR survey provides a coverage of roughly 2.1 square degrees ( 300 SOFI pointings) in Ks with 0.63 square degrees to fainter magnitudes and also covered in J, over three independent regions of the sky. The goal of the present paper is to briefly describe the observations, the data reduction procedures, and to present the final survey products which include fully calibrated pixel-maps and catalogs extracted from them. The astrometric solution with an estimated accuracy of ⪉0.15 arcsec is based on the USNO catalog and limited only by the accuracy of the reference catalog. The final stacked images presented here number 89 and 272, in J and K_s, respectively, the latter reflecting the larger surveyed area. The J and Ks images were taken with a median seeing of 0.77 arcsec and 0.8 arcsec. The images reach a median 5σ limiting magnitude of JAB˜23.06 as measured within an aperture of 2´´, while the corresponding limiting magnitude in KsAB is 21.41 and 22.16 mag for the shallow and deep strategies. Although some spatial variation due to varying observing conditions is observed, overall the observed limiting magnitudes are consistent with those originally proposed. The quality of the data

  2. Atmospheric prediction model survey

    NASA Technical Reports Server (NTRS)

    Wellck, R. E.

    1976-01-01

    As part of the SEASAT Satellite program of NASA, a survey of representative primitive equation atmospheric prediction models that exist in the world today was written for the Jet Propulsion Laboratory. Seventeen models developed by eleven different operational and research centers throughout the world are included in the survey. The surveys are tutorial in nature describing the features of the various models in a systematic manner.

  3. Unmanned aerial vehicles (UAVs) for surveying marine fauna: a dugong case study.

    PubMed

    Hodgson, Amanda; Kelly, Natalie; Peel, David

    2013-01-01

    Aerial surveys of marine mammals are routinely conducted to assess and monitor species' habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km(2) area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as 'certain' (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for marine mammal aerial surveys.

  4. Unmanned aerial vehicles (UAVs) for surveying marine fauna: a dugong case study.

    PubMed

    Hodgson, Amanda; Kelly, Natalie; Peel, David

    2013-01-01

    Aerial surveys of marine mammals are routinely conducted to assess and monitor species' habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km(2) area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as 'certain' (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for marine mammal aerial surveys. PMID:24223967

  5. Unmanned Aerial Vehicles (UAVs) for Surveying Marine Fauna: A Dugong Case Study

    PubMed Central

    Hodgson, Amanda; Kelly, Natalie; Peel, David

    2013-01-01

    Aerial surveys of marine mammals are routinely conducted to assess and monitor species’ habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km2 area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as ‘certain’ (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for marine mammal aerial surveys. PMID:24223967

  6. Geophysical Interpretations of the Southern Espanola Basin, New Mexico, That Contribute to Understanding Its Hydrogeologic Framework

    USGS Publications Warehouse

    Grauch, V.J.S.; Phillips, Jeffrey D.; Koning, Daniel J.; Johnson, Peggy S.; Bankey, Viki

    2009-01-01

    The southern Espanola basin consists of a westward- and northward-thickening wedge of rift fill, composed primarily of Santa Fe Group sediments, that serves as an important aquifer for the city of Santa Fe and surrounding areas. Detailed aeromagnetic surveys were flown to better understand ground-water resources in this aquifer. This report presents a synthesis of these data with gravity data and other constraints. The interpretations were accomplished using qualitative interpretation, state-of-art data analysis techniques, and two- and three-dimensional modeling. The results depict the presence of and depth to many geologic features that have hydrogeologic significance, including shallow faults, different types of igneous units, and basement rocks. The results are presented as map interpretations, geophysical profile models, and a digital surface that represents the base and thickness of Santa Fe Group sediments, as well as vector files of some volcanic features and faults.

  7. Magnetic anomalies northeast of Cape Adare, northern Victoria Land (Antarctica), and their relation to onshore structures

    USGS Publications Warehouse

    Damaske, D.; Läufer, A.L.; Goldmann, F.; Möller, H.-D.; Lisker, F.

    2007-01-01

    An aeromagnetic survey was flown over the offshore region northeast of Cape Adare and the magnetic anomalies compared to onshore structures between Pennell Coast and Tucker Glacier. The magnetic anomalies show two nearly orthogonal major trends. NNW-SSE trending anomalies northeast of Cape Adare represent seafloor spreading within the Adare Trough. A connection of these anomalies to the Northern Basin of the Ross Sea is not clear. Onshore faults are closely aligned to offshore anomalies. Main trends are NW-SE to NNW-SSE and NE-SW to NNESSW. NNW-SSE oriented dextral-transtensional to extensional faults parallel the Adare Peninsula and Adare Trough anomalies. NE-SW trending normal faults appear to segment the main Hallett volcanic bodies.

  8. Application Trends Survey. 2014 Survey Report

    ERIC Educational Resources Information Center

    Worthington, Rebecca; Bruggeman, Paula

    2014-01-01

    Now in its 15th year, the Graduate Management Admission Council's assessment of application volume trends for graduate management programs offers timely insights into demographic shifts and other factors defining the candidate pools for the 2014 application cycle. Responses collected in the 2014 survey represent a record-breaking total of 748 MBA,…

  9. Corporate Recruiters Survey: 2014 Survey Report

    ERIC Educational Resources Information Center

    Estrada Worthington, Rebecca

    2014-01-01

    The 2014 Corporate Recruiters Survey Report examines the current hiring outlook for graduate business students and analyzes demand by industry and world region, salaries, job functions, and mobility in regional job placement. It also explores recruiter behavior, including recruitment practices and school and candidate selection criteria, and…

  10. Application Trends Survey, 2011. Survey Report

    ERIC Educational Resources Information Center

    Estrada, Rebecca

    2011-01-01

    The 2011 Application Trends Survey conducted by the Graduate Management Admission Council (GMAC) is the industry source for comprehensive statistics and timely and reliable insights into the demand for graduate management education around the world. A total of 649 programs from 331 business schools and faculties worldwide representing 45 countries…

  11. Alumni Perspectives Survey, 2011. Survey Report

    ERIC Educational Resources Information Center

    Sheikh, Sabeen

    2011-01-01

    Since the Graduate Management Admission Council[R] (GMAC[R]) first began conducting its Alumni Perspectives Surveys 11 years ago, several "truths" about graduate business school alumni have consistently stood the test of time: They are and remain eminently employable. They constantly rate the value of the degree highly. This year's results are…

  12. Alumni Perspectives Survey. 2014 Survey Report

    ERIC Educational Resources Information Center

    Schoenfeld, Gregg

    2014-01-01

    Alumni are a powerful force in building a business school's brand. They recommend programs to prospective students, they connect current students to job opportunities, and they contribute significantly to building a school's legacy. The findings in the 2014 Alumni Perspectives Survey Report provide a current snapshot of nearly 21,000 business…

  13. Infrastructure Survey 2009

    ERIC Educational Resources Information Center

    Group of Eight (NJ1), 2010

    2010-01-01

    In 2008 the Group of Eight (Go8) released a first report on the state of its buildings and infrastructure, based on a survey undertaken in 2007. A further survey was undertaken in 2009, updating some information about the assessed quality, value and condition of buildings and use of space. It also collated data related to aspects of the estate not…

  14. Seven Survey Sins

    ERIC Educational Resources Information Center

    Gehlbach, Hunter

    2015-01-01

    As pressure builds to assess students, teachers, and schools, educational practitioners and policy makers are increasingly looking toward student perception surveys as a promising means to collect high-quality, useful data. For instance, the widely cited Measures of Effective Teaching study lists student perception surveys as one of the three key…

  15. Basic Surveying Technology.

    ERIC Educational Resources Information Center

    Olson, David A.; Kellum, Mary, Ed.

    This document is intended to help teachers prepare students to perform the duties of any member of a surveying party, including those of party chief, in the field and in the office. It contains instructional units on introduction to surveying, safety, horizontal measurements, vertical measurements, angles and directions, angular measurements,…

  16. Leaver Survey Report, 1996.

    ERIC Educational Resources Information Center

    Cunningham, Stephen

    To determine factors influencing attrition and retention at Pennsylvania College of Technology, a survey was conducted of the 688 students who were enrolled in spring 1996 but neither graduated nor enrolled in fall 1996. Responses were received from 437 former students and were compared to findings from a similar survey of 482 leavers in 1994.…

  17. Submarine cable route survey

    SciTech Connect

    Herrouin, G.; Scuiller, T.

    1995-12-31

    The growth of telecommunication market is very significant. From the beginning of the nineties, more and more the use of optical fiber submarine cables is privileged to that of satellites. These submarine telecommunication highways require accurate surveys in order to select the optimum route and determine the cable characteristics. Advanced technology tools used for these surveys are presented along with their implementation.

  18. Freshman Survey Report, 1997.

    ERIC Educational Resources Information Center

    Cunningham, Steve; Hiris, Eric

    The Cooperative Institutional Research Program (CIRP) sponsors a national annual survey that gathers data on incoming freshman classes at two- and four-year institutions. The data allow the colleges to compare their students with previous classes and with the "average" American freshman. This report presents findings from the 1997 CIRP survey at…

  19. And the Survey Says...

    ERIC Educational Resources Information Center

    White, Susan C.

    2016-01-01

    Last month we highlighted our Quadrennial Survey of High School Physics Teachers. Using data from the survey, we have looked at the availability of high school physics. We report that about 95% of high school seniors attend a high school where physics is offered regularly--either every year or every other year. A U.S. Department of Education…

  20. Maryland Adolescent Survey, 1994.

    ERIC Educational Resources Information Center

    Maryland State Dept. of Education, Baltimore. Div. of Compensatory Education and Support Services.

    This report details the latest findings from the biennial Maryland Adolescent Survey of the extent and trends in alcohol, tobacco, and drug use among students. To permit comparisons with national findings and trends, the form and content of survey items parallel those of the annual national study "Monitoring the Future," conducted by the…

  1. University Community Survey.

    ERIC Educational Resources Information Center

    Francis, John Bruce; Lewis, Steven

    This report is of an omnibus survey of campus attitudes conducted by the Survey Research Center (SRC) of the State University of New York at Buffalo. Its primary purpose was to provide accurate information as a basis for effective decisions by institutional policy makers. A random sample of 326 students, 98 faculty, and 95 staff participated in…

  2. Attitude Surveys Document Sampler.

    ERIC Educational Resources Information Center

    Walker, Albert, Comp.

    This packet presents results of a series of attitude surveys representing a variety of purposes, methods and defined publics. They range from a simple questionnaire prepared and mailed to a small group of key individuals by a public relations staff to scientifically derived surveys purchased from Louis Harris and Associates and other research…

  3. Managing Online Survey Data

    ERIC Educational Resources Information Center

    Ritter, Lois A., Ed.; Sue, Valerie M., Ed.

    2007-01-01

    Managing data collected from online surveys may be a straightforward process involving no more than downloading a spreadsheet from a Web survey host and presenting descriptive statistics associated with each questionnaire item. On the other hand, if the evaluation objectives require more complex analysis and presentation of the data, it will be…

  4. Readership Surveys Build Confidence.

    ERIC Educational Resources Information Center

    Bohle, Bob

    1980-01-01

    Reports results of a survey of students' opinions of their school newspaper. Lists four changes that were based on the survey results: (1) added emphasis on meeting students' personal interest needs, (2) increase in short feature and humorous stories, (3) more persuasive editorial and opinion pieces, and (4) increase in advertising benefits for…

  5. Technology & Distance Learning Survey.

    ERIC Educational Resources Information Center

    Florida Human Resources Development, Inc., Gainesville.

    A survey was conducted to assess the current state of technology and distance learning awareness and usage in Florida's adult education and community-based programs. Data were gathered through a survey of 350 adult practitioners, literacy providers, community-based organizations and libraries throughout the state (125 responses [36 percent return…

  6. Surveying the Community.

    ERIC Educational Resources Information Center

    Brown, Marleen

    The booklet serves as a step-by-step guide to assist career education teachers and administrators in setting up a program of utilizing the resources in the community. It provides specific procedures, forms, and suggestions to help the school in surveying the community. Nine steps involved in surveying the community are discussed in detail: (1)…

  7. 2007 Maryland Adolescent Survey

    ERIC Educational Resources Information Center

    Maryland State Department of Education, 2008

    2008-01-01

    Periodically, Maryland's sixth, eighth, tenth, and twelfth graders are surveyed to determine the nature, extent, and trend of alcohol, tobacco, and other drug (ATOD) use among adolescents. The "2007 Maryland Adolescent Survey (MAS)" presents the latest findings regarding ATOD use by Maryland's adolescents and compares State and local findings with…

  8. Annual HR Salary Survey.

    ERIC Educational Resources Information Center

    Schaeffer, Patricia

    2000-01-01

    A trainers' salary survey collected data on 1,091 companies, 31,615 employees, and 97 human resource jobs. Results show pay for human resource professionals is continuing to rise. The survey contains information on base salaries, annual bonuses and incentives, and long-term eligibility incentives. (JOW)

  9. Physics Survey Overview

    SciTech Connect

    2002-12-30

    An overview of a series of assignments of the branches of physics carried out by the Board on Physics and Astronomy of the National Research Council. It identifies further theories in physics and makes recommendations on preventive priorities. The Board on Physics and Astronomy (BPA) has conducted a new decadal survey of physics entitled ''Physics in a New Era''. The survey includes assessments of the main branches of physics as well as certain selected emerging areas. The various elements of the survey were prepared by separately-appointed National Research Council (NRC) committees. The BPA formed the Physics Survey Overview Committee (PSOVC) to complete the survey by preparing an overview of the field of physics to summarize and synthesize the results of the various assessments and to address cross-cutting issues that concern physics as a whole.

  10. Building Technologies Residential Survey

    SciTech Connect

    Secrest, Thomas J.

    2005-11-07

    Introduction A telephone survey of 1,025 residential occupants was administered in late October for the Building Technologies Program (BT) to gather information on residential occupant attitudes, behaviors, knowledge, and perceptions. The next section, Survey Results, provides an overview of the responses, with major implications and caveats. Additional information is provided in three appendices as follows: - Appendix A -- Summary Response: Provides summary tabular data for the 13 questions that, with subparts, comprise a total of 25 questions. - Appendix B -- Benchmark Data: Provides a benchmark by six categories to the 2001 Residential Energy Consumption Survey administered by EIA. These were ownership, heating fuel, geographic location, race, household size and income. - Appendix C -- Background on Survey Method: Provides the reader with an understanding of the survey process and interpretation of the results.

  11. The Methanol Multibeam Survey

    NASA Astrophysics Data System (ADS)

    Green, James A.; Cohen, R. J.; Caswell, J. L.; Fuller, G. A.; Brooks, K.; Burton, M. G.; Chrysostomou, A.; Diamond, P. J.; Ellingsen, S. P.; Gray, M. D.; Hoare, M. G.; Masheder, M. R. W.; McClure-Griffiths, N.; Pestalozzi, M.; Phillips, C.; Quinn, L.; Thompson, M. A.; Voronkov, M.; Walsh, A.; Ward-Thompson, D.; Wong-McSweeney, D.; Yates, J. A.; Cox, J.

    2007-03-01

    A new 7-beam methanol multibeam receiver is being used to survey the Galaxy for newly forming massive stars, that are pinpointed by strong methanol maser emission at 6.668 GHz. The receiver, jointly constructed by Jodrell Bank Observatory (JBO) and the Australia Telescope National Facility (ATNF), was successfully commissioned at Parkes in January 2006. The Parkes-Jodrell survey of the Milky Way for methanol masers is two orders of magnitude faster than previous systematic surveys using 30-m class dishes, and is the first systematic survey of the entire Galactic plane. The first 53 days of observations with the Parkes telescope have yielded 518 methanol sources, of which 218 are new discoveries. We present the survey methodology as well as preliminary results and analysis.

  12. Web-Based Surveys: Not Your Basic Survey Anymore

    ERIC Educational Resources Information Center

    Bertot, John Carlo

    2009-01-01

    Web-based surveys are not new to the library environment. Although such surveys began as extensions of print surveys, the Web-based environment offers a number of approaches to conducting a survey that the print environment cannot duplicate easily. Since 1994, the author and others have conducted national surveys of public library Internet…

  13. Infrared survey of the Pisgah Crater area, San Bernardino County, California - a geologic interpretation

    USGS Publications Warehouse

    Gawarecki, Stephen J.

    1968-01-01

    portion of the Sunshine lava flow and the dry lake. Additional aerial infrared imagery of the Sunshine and Pisgah flows along the Pisgah fault proved so interesting and informative that this area is included in the discussion. Infrared surveys were flown February ii through 13, 1965 and August 5 and 9, 1966. The initial survey was flown by the NASA personnel aboard the NASA 926 Convair 240 aircraft. Because of technical problems with the infrared scanners (4.5-5.5 and 8-14 micron bands) and with certain ground instruments, most of the imagery and ground temperature data obtained during the initial survey period was of little value. However, excellent infrared imagery in the 8-14 micron (?) region of the spectrum was acquired by the Geological Survey during the August 1966 survey. The scanner was mounted in a Beech D-18 aircraft provided by the Survey's Water Resources Division. Likewise, more reliable ground data was obtained at this time owing to improved instrumentation and technique. Ground data were taken by Geological Survey personnel including W. A. Fischer, J. D. Friedman, W. R. Hemphill, D. L. Daniels, G. R. Boynton, Po W. Philbin and the author. C. R. Fross operated the infrared scanner during the August, 1966 survey and R. M. Turner was-responsible for photo processing of the infrared imagery. Their assistance is gratefully acknowledged.

  14. The alpine Swiss-French airborne gravity survey

    NASA Astrophysics Data System (ADS)

    Verdun, Jérôme; Klingelé, Emile E.; Bayer, Roger; Cocard, Marc; Geiger, Alain; Kahle, Hans-Gert

    2003-01-01

    In February 1998, a regional-scale, airborne gravity survey was carried out over the French Occidental Alps within the framework of the GéoFrance 3-D research program.The survey consisted of 18 NS and 16 EW oriented lines with a spacing of 10 and 20 km respectively, covering the whole of the Western French Alps (total area: 50 000 km2; total distance of lines flown: 10 000 km). The equipment was mounted in a medium-size aircraft (DeHavilland Twin Otter) flowing at a constant altitude of 5100 m a.s.l, and at a mean ground speed of about 280 km h-1. Gravity was measured using a LaCoste & Romberg relative, air/sea gravimeter (type SA) mounted on a laser gyro stabilized platform. Data from 5 GPS antennae located on fuselage and wings and 7 ground-based GPS reference stations were used to determine position and aircraft induced accelerations.The gravimeter passband was derived by comparing the vertical accelerations provided by the gravimeter with those estimated from the GPS positions. This comparison showed that the gravimeter is not sensitive to very short wavelength aircraft accelerations, and therefore a simplified formulation for computing airborne gravity measurements was developed. The intermediate and short wavelength, non-gravitational accelerations were eliminated by means of digital, exponential low-pass filters (cut-off wavelength: 16 km). An important issue in airborne gravimetry is the reliability of the airborne gravity surveys when compared to ground surveys. In our studied area, the differences between the airborne-acquired Bouguer anomaly and the ground upward-continued Bouguer anomaly of the Alps shows a good agreement: the rms of these differences is equal to 7.68 mGal for a spatial resolution of 8 km. However, in some areas with rugged topography, the amplitudes of those differences have a striking correlation with the topography. We then argue that the choice of an appropriate density (reduction by a factor of 10 per cent) for computing the

  15. The US Experiments Flown on the Soviet Biosatellite Cosmos 1887

    NASA Technical Reports Server (NTRS)

    Connolly, James P. (Editor); Grindeland, Richard E. (Editor); Ballard, Rodney W. (Editor)

    1990-01-01

    Cosmos 1887, a biosatellite containing biological and radiation experiments from the Soviet Union, the United States and seven other countries, was launched on September 29, 1987. One Rhesus monkey's feeder stopped working two days into the flight and a decision was made to terminate the mission after 12 1/2 days. The biosatellite returned to Earth on October 12, 1987. A system malfunction, during the reentry procedure, caused the Cosmos 1887 spacecraft to land approximately 1800 miles beyond the intended landing site and delayed the start of the postflight procedures by approximately 44 hours. Further information on the conditions at landing and postflight activities is included in the Mission Operations portion of this document. U.S. and U.S.S.R. specialists jointly conducted 26 experiments on this mission, including the postflight transfer of data, hardware and biosamples to the U.S.

  16. US experiments flown on the Soviet satellite COSMOS 936

    NASA Technical Reports Server (NTRS)

    Rosenzweig, S. N.; Souza, K. A.

    1978-01-01

    Results of spaceborne experiments onboard the Cosmos 936 satellite are reported. Alterations in normal bone chemistry, muscle structure, and general physiology resulting from spaceflight are covered along with measurements of cosmic radiation and its potential hazard to man during prolonged spaceflights. Postflight activities involving the seven U.S. experiments are emphasized.

  17. Surface electrical properties experiment, part 1. [flown on Apollo 17

    NASA Technical Reports Server (NTRS)

    Strangway, D. W.; Annan, A. P.; Redman, J. D.; Rossiter, J. R.; Rylaarsdam, J. A.; Watts, R. D.

    1974-01-01

    The work is reported which was performed on the Surface Electrical Properties Experiment Data Acquisition System. Areas discussed include: data handling and processing, installation and external signal application, operation of the equipment, and digital output. Detailed circuit descriptions are included.

  18. Hemopoietic tissue in newts flown aboard Foton M3

    NASA Astrophysics Data System (ADS)

    Domaratskaya, Elena I.; Almeida, Eduardo; Butorina, Nina N.; Nikonova, Tatyana M.; Grigoryan, Eleonora N.; Poplinskaya, Valentina A.; Souza, Kenneth; Skidmore, Mike

    The effect of 12-day spaceflight aboard the Foton-M3 biosatellite on the hematopoietic tissue of P. waltl newts was studied. These animals used at the same time in regeneration experiments after lens and tail tip amputation. In flight and synchronous groups there were performed video recording, temperature and radiation monitoring and continuous contact (via skin) with thymidine analog BrdU. We took differential blood counts and assessed histologically the liver in the flight (F), basal (BC) and synchronous (SC)control groups of animals. In the peripheral blood, we identified neutrophils, eosinophils, basophils, lymphocytes, and monocytes. Lymphocytes (L) and neutrophils (N) prevailed, accounting for about 60 and 20% of white blood cells, respectively. The spaceflight had no apparent effect on the differential blood count in the F group: neither the L and N contents nor the maturing to mature N - ratio differed from those in the control groups. No significant differences between F, SC and BC groups were observed with respect to the structure of hematopoietic areas and the liver morphology. As in Foton-M2, BrdU labeled cells revealed in blood as well as in the hemopoietic areas of the liver. However, in previous experiments performed at satellites Bion-10 and Foton-M2 the changes in peripheral blood contents were registered in operated F newts, and we supposed it could be the result of additive effects of spaceflight factors and stimulation of reparative potency and stress due to surgical operation. Possibly, the temperature conditions also may provide some influence on blood cell content of newts that belong to poikilothermic animals. Thus, in present experiment F and SC groups were reared in the same temperature regims, whereas it was nearly 3o C differences between SC and F groups exposed on Foton-M2. At the same time as it was found in experiments on Bion-11 and Foton-M2 spaceflight factors did not affect on differential blood counts of intact non-operated animals. The lack of pronounced blood changes in newts distinguishes them from rats and mice, which characterized marked differences either in cell content in peripheral blood or hemopoietic stem and committed cells in blood-forming tissues. Therefore taken together the data demonstrate that hemopoietic responses spaceflight factors of species from different taxonomic groups are dissimilar.

  19. Hematologic parameters of astrorats flown on SL-3

    NASA Technical Reports Server (NTRS)

    Lange, R. D.; Andrews, R. B.; Gibson, L. A.; Wright, P.; Dunn, C. D. R.

    1985-01-01

    Hematologic studies were performed on a group of large and small rats which were sacrificed after flying in life sciences shuttle engineering flight SL-3. The results are presented on flight (F) and control (C) 200 gm rats. The small flight animals demonstrated a significant increase in hematocrits, red blood cell counts, hemoglobins and peripheral blood percentages of neutrophils as well as a decrease in percentage of lymphocytes. Erythropoietin (Ep) determinations were similar for the two groups as were the bone marrow an spleen differential counts. In vitro cultures for erythroid colonies of bone marrow showed that in response to different doses of Ep, in all cases where differnces were statistically significant, the F rats had increased colony counts. The changes in red cell parameters could be caused by a decrease in plasma volume. However, no isotopic studies were possible on this flight and this lack points up the need for such studies to determine the red cell mass and plasma volume.

  20. Astronaut Returns Space-Flown Flag to NRAO

    NASA Astrophysics Data System (ADS)

    2002-04-01

    A NASA Astronaut who carried a flag bearing the logo of the National Radio Astronomy Observatory (NRAO) on last month's Shuttle flight returned that flag to the observatory on Friday, April 12, at a ceremony in Socorro. Dr. John M. Grunsfeld, payload commander of the STS-109 flight, also addressed students at the New Mexico State Science Fair on Saturday, April 13, on the campus of New Mexico Tech in Socorro. Dr. John M. Grunsfeld: Click on image for larger view Dr. John M. Grunsfeld Grunsfeld, an astronomer who observed with NRAO's Very Large Array (VLA) radio telescope in 1991, carried the 3-by-5-foot NRAO flag aboard Columbia during the March 1-12 mission to service the Hubble Space Telescope. The NRAO flag, made by Socorro resident Dora Spargo, had been sent to the observatory's facilities in Socorro; Tucson, AZ; Green Bank, WV; and Charlottesville, VA, where NRAO employees signed it prior to the flight. "With our signatures on that flag, we all felt like we were riding along with John aboard the Shuttle," said NRAO Director Paul Vanden Bout. "We are proud that NRAO was represented on a mission that was so important to astronomy," Vanden Bout added. During the flight, Grunsfeld performed three of the five spacewalks in which crew members successfully upgraded the Hubble Space Telescope. The astronauts left the space observatory with a new power unit, a new camera and new solar arrays. The upgrades, said Grunsfeld, leave the orbiting telescope with "its discovery potential significantly increased." STS-109 was Grunsfeld's fourth space flight and his second visit to Hubble. A research astronomer who received his bachelor's degree in physics from MIT and a Ph.D from the University of Chicago in 1988, Grunsfeld was selected to the astronaut corps in 1992. His first space flight, in 1995, featured astronomical observations using the Astro observatory, a three-telescope facility aboard the Shuttle Endeavour. In 1997, Grunsfeld rode Atlantis on a 10-day mission to the Russian space station Mir. In 1999, he performed two space walks during a Discovery mission to install new instruments on Hubble. In 1991, while a senior research fellow at Caltech, Grunsfeld was the principal investigator for a series of VLA observations of a gamma-ray-emitting object, conducted at the same time the object was observed by the orbiting Compton Gamma Ray Observatory. "I still think fondly of my observations at the VLA," said Grunsfeld. During his visit to New Mexico, Grunsfeld formally presented the NRAO flag to the observatory, along with documentation of its flight aboard Columbia. He also addressed the awards ceremonies of the New Mexico State Science Fair. "We are particularly pleased that John's visit allowed him to speak to the science fair students," said Jim Ulvestad, NRAO's Assistant Director for New Mexico operations. "Those students heard from someone whose science training has literally taken him beyond the Earth," Ulvestad said. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.