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Sample records for basalt gusev crater

  1. Basaltic rocks analyzed by the Spirit rover in Gusev crater

    Science.gov (United States)

    McSween, H.Y.; Arvidson, R. E.; Bell, J.F.; Blaney, D.; Cabrol, N.A.; Christensen, P.R.; Clark, B. C.; Crisp, J.A.; Crumpler, L.S.; Des Marias, D.J.; Farmer, J.D.; Gellert, Ralf; Ghosh, A.; Gorevan, S.; Graff, T.; Grant, J.; Haskin, L.A.; Herkenhoff, K. E.; Johnson, J. R.; Jolliff, B.L.; Klingelhoefer, G.; Knudson, A.T.; McLennan, S.; Milam, K.A.; Moersch, J.E.; Morris, R.V.; Rieder, R.; Ruff, S.W.; De Souza, P.A.; Squyres, S. W.; Wanke, H.; Wang, A.; Wyatt, M.B.; Yen, A.; Zipfel, J.

    2004-01-01

    The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain ???25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mo??ssbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.

  2. Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars

    Science.gov (United States)

    McSween, H.Y.; Wyatt, M.B.; Gellert, Ralf; Bell, J.F.; Morris, R.V.; Herkenhoff, K. E.; Crumpler, L.S.; Milam, K.A.; Stockstill, K.R.; Tornabene, L.L.; Arvidson, R. E.; Bartlett, P.; Blaney, D.; Cabrol, N.A.; Christensen, P.R.; Clark, B. C.; Crisp, J.A.; Des Marais, D.J.; Economou, T.; Farmer, J.D.; Farrand, W.; Ghosh, A.; Golombek, M.; Gorevan, S.; Greeley, R.; Hamilton, V.E.; Johnson, J. R.; Joliff, B.L.; Klingelhofer, G.; Knudson, A.T.; McLennan, S.; Ming, D.; Moersch, J.E.; Rieder, R.; Ruff, S.W.; Schrorder, C.; de Souza, P.A.; Squyres, S. W.; Wanke, H.; Wang, A.; Yen, A.; Zipfel, J.

    2006-01-01

    Rocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric shergottites). The olivine megacrysts in both have intermediate compositions, with modal abundances ranging up to 20-30%. Associated minerals in both include low-calcium and high-calcium pyroxenes, plagioclase of intermediate composition, iron-titanium-chromium oxides, and phosphate. These rocks also share minor element trends, reflected in their nickel-magnesium and chromium-magnesium ratios. Gusev basalts and shergottites appear to have formed from primitive magmas produced by melting an undepleted mantle at depth and erupted without significant fractionation. However, apparent differences between Gusev rocks and shergottites in their ages, plagioclase abundances, and volatile contents preclude direct correlation. Orbital determinations of global olivine distribution and compositions by thermal emission spectroscopy suggest that olivine-rich rocks may be widespread. Because weathering under acidic conditions preferentially attacks olivine and disguises such rocks beneath alteration rinds, picritic basalts formed from primitive magmas may even be a common component of the Martian crust formed during ancient and recent times. Copyright 2006 by the American Geophysical Union.

  3. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

  4. Acid Sulfate Alteration in Gusev Crater, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Catalano, J. G.

    2016-01-01

    The Mars Exploration Rover (MER) Spirit landed on the Gusev Crater plains west of the Columbia Hills in January, 2004, during the Martian summer (sol 0; sol = 1 Martian day = 24 hr 40 min). Spirit explored the Columbia Hills of Gusev Crater in the vicinity of Home Plate at the onset on its second winter (sol approximately 900) until the onset of its fourth winter (sol approximately 2170). At that time, Spirit became mired in a deposit of fined-grained and sulfate-rich soil with dust-covered solar panels and unfavorable pointing of the solar arrays toward the sun. Spirit has not communicated with the Earth since sol 2210 (January, 2011). Like its twin rover Opportunity, which landed on the opposite side of Mars at Meridiani Planum, Spirit has an Alpha Particle X-Ray Spectrometer (APXS) instrument for chemical analyses and a Moessbauer spectrometer (MB) for measurement of iron redox state, mineralogical speciation, and quantitative distribution among oxidation (Fe(3+)/sigma Fe) and coordination (octahedral versus tetrahedral) states and mineralogical speciation (e.g., olivine, pyroxene, ilmenite, carbonate, and sulfate). The concentration of SO3 in Gusev rocks and soils varies from approximately 1 to approximately 34 wt%. Because the APXS instrument does not detect low atomic number elements (e.g., H and C), major-element oxide concentrations are normalized to sum to 100 wt%, i.e., contributions of H2O, CO2, NO2, etc. to the bulk composition care not considered. The majority of Gusev samples have approximately 6 plus or minus 5 wt% SO3, but there is a group of samples with high SO3 concentrations (approximately 30 wt%) and high total iron concentrations (approximately 20 wt%). There is also a group with low total Fe and SO3 concentrations that is also characterized by high SiO2 concentrations (greater than 70 wt%). The trend labeled "Basaltic Soil" is interpreted as mixtures in variable proportions between unaltered igneous material and oxidized and SO3-rich basaltic

  5. 3D structure of the Gusev Crater region

    NARCIS (Netherlands)

    van Kan - Parker, M.; Zegers, T.E.; kneissl, T.; Ivanov, B.; Neukum, G.; Foing, B.

    2010-01-01

    Gusev Crater lies within the Aeolis Quadrangle of Mars at the boundary between the northern lowlands and southern highlands. The ancient valley Ma'adim Vallis dissects the highlands south of Gusev Crater and is thought to have fed the crater with sediments.High Resolution Stereo Camera data and

  6. Gusev Crater by Day and Night

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 23 June 2004 This pair of images shows part of Gusev Crater. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude -14.5, Longitude 175.5 East (184.5 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project

  7. The alkaline volcanic rocks of Craters of the Moon National Monument, Idaho and the Columbia Hills of Gusev Crater, Mars

    Science.gov (United States)

    Neakrase, L. D.; Lim, D. S. S.; Haberle, C. W.; Hughes, S. S.; Kobs-Nawotniak, S. E.; Christensen, P. R.

    2016-12-01

    Idaho's Eastern Snake River Plain (ESRP) is host to extensive expressions of basaltic volcanism dominated by non evolved olivine tholeiites (NEOT) with localized occurrences of evolved lavas. Craters of the Moon National Monument (COTM) is a polygenetic lava field comprised of more than 60 lava flows emplaced during 8 eruptive periods spanning the last 15 kyrs. The most recent eruptive period (period A; 2500-2000 yr B.P.) produced flows with total alkali vs. silica classifications spanning basalt to trachyte. Coeval with the emplacement of the COTM period A volcanic pile was the emplacement of the Wapi and King's Bowl NEOT 70 km SSE of COTM along the Great Rift. Previous investigations have determined a genetic link between these two compositionally distinct volcanic centers where COTM compositions can be generated from NEOT melts through complex ascent paths and variable degrees of fractionation and assimilation of lower-middle crustal materials. The Mars Exploration Rover, Spirit, conducted a robotic investigation of Gusev crater from 2004-2010. Spirit was equipped with the Athena science payload enabling the determination of mineralogy (mini-Thermal Emission Spectrometer, Pancam multispectral camera, and Mössbauer spectrometer), bulk chemistry (Alpha Particle X-ray Spectrometer) and context (Pancam and Microscopic Imager). During sol 32 Spirit investigated an olivine basalt named Adirondack, the type specimen for a class of rock that composes much of the plains material within Gusev Crater and embays the Columbia Hills. Following the characterization of the plains material, Spirit departed the plains targeting the Columbia Hills and ascending at Husband Hill. During Spirit's ascent of Husband Hill three additional classes of volcanic rock were identified as distinct by their mini-TES spectra; Wishstone, Backstay and Irvine. These rocks are classified as tephrite, trachy-basalt and basalt, respectively, and are the first alkaline rocks observed on Mars. These

  8. The Context of Carbonates in Gusev and Jezero Craters

    Science.gov (United States)

    Ruff, S. W.; Hamilton, V. E.

    2017-12-01

    Gusev and Jezero are Noachian-aged craters with evidence of a lake in early Mars history. Both are among three remaining candidates for the Mars 2020 rover mission, which is intended to collect and cache rock samples for possible future return to Earth. Gusev was explored by the Spirit rover from 2004 to 2010, revealing outcrops dubbed Comanche composed of olivine-rich volcanic tephra that hosts up to 30% Mg-Fe carbonate, clear evidence for the role of near-neutral pH fluids [1]. Jezero also displays evidence for olivine- and carbonate-bearing materials, likely Mg-carbonate based on orbital spectral observations [2]. In both craters, the carbonates occur in materials that are among the oldest stratigraphic units in each, perhaps an indication of more clement climatic conditions on early Mars compared to those that prevailed for most of its history. We are undertaking investigations of various rover-based and orbital measurements of the carbonates in Gusev to better understand their geologic context and origin. In doing so, the results shed light on carbonate occurrences in Jezero. The Comanche outcrops are contained in the Columbia Hills, which represent a kipuka or island of eroded older terrain fully encircled by lava flows, here with a crater retention age of 3.65 Ga (Fig. 1). In situ and orbital observations [3] demonstrate that carbonate-bearing outcrops extend beyond those visited by Spirit. The distinctive morphology and thermal inertia signature of these outcrops and their unaltered host rocks are recognizable in other kipukas on the floor of Gusev [4]. Carbonate also occurs in kipukas in Jezero (Fig. 2), but larger occurrences extend beyond the crater rim and in isolated places among the delta fan deposits [2]. The presence of carbonates outside of the crater suggests an origin unrelated to a former lake, unlike the Comanche carbonates, which may have arisen through evaporation of dilute brines from an ephemeral lake in Gusev [4]. In both cases, the clear

  9. Two Martian Winters at Gusev Crater and Meridiani Planum: New Results From the MER Mossbauer Spectrometers

    Science.gov (United States)

    Klingelhoefer, Goestar; Morris, Richard V.; Schroeder, Christian; Rodionov, Daniel S.; Yen, Albert S.; Ming, Douglas W.; Cohen, Barbara A.; Fleischer, Iris; Mittlefehldt, David W.; McCoy, Tim; hide

    2006-01-01

    After sol 511 of its mission in Gusev Crater, Spirit traversed from the top of Husband Hill to its current Winter Haven on Low Ridge. M ssbauer analyses of several rock and soil targets along the traverse yielded further evidence for the wide-spread occurrence of aqueous processes in the Columbia Hills. The rock Independence was found on the flank of Husband Hill. It has low total Fe with about 24-30 % of its iron in ilmenite. This assemblage implies alteration under aqueous conditions; some phases were altered and elements such as Fe were leached out, while less soluble Fe-bearing phases such as ilmenite remain. The soil target Dead_Sea_Samra was found in subsurface soil revealed when the wheels dug into soil during the traverse from Husband Hill to Home Plate. Its M ssbauer spectrum shows a high abundance of ferric sulfate, similar to the Paso Robles soil targets found on Husband Hill. At its current location at Winter Haven Spirit investigated the target Halley which appears to be part of a wider-spread indurated layer underlying basaltic soil. This target shows the highest abundance of hematite in all Gusev soil and rock targets investigated to date. Opportunity at Meridiani Planum traversed from the 300 m diameter buried Erebus Crater towards 800 m Victoria Crater. The main components of Meridiani Planum jarosite-bearing outcrop rocks, basaltic soil, and a hematite lag remain remarkably constant in M ssbauer spectra throughout the traverse. Cobbles (rock fragments greater than 1 cm) show variability however. A meteorite (Barberton) has been identified based on kamacite peaks in the M ssbauer spectrum. Other cobbles show Mossbauer spectra similar to jarosite-bearing outcrops, or to basaltic rock, or mixtures thereof, suggesting an origin as impact breccias. Some cobbles were investigated at the edge of the annulus of Victoria Crater from which they may have been excavated. Mossbauer spectra reveal a basaltic signature, dominated by olivine and pyroxene. In

  10. Abraded Target on Rock 'Champagne' in Gusev Crater

    Science.gov (United States)

    2005-01-01

    NASA's Mars Exploration Rover Spirit took this microscopic image of a target called 'Bubbles' on a rock called 'Champagne' after using its rock abrasion tool to grind a hole through the rock's outer surface. The circular area where the rock's interior is exposed is about 5 centimeters (2 inches) across. This rock is different from rocks out on the plains of Gusev Crater but is similar to other rocks in this area of the 'Columbia Hills' in that it rich in phosphorus. Plagioclase, a mineral commonly found in igneous rocks, is also present in these rocks, according to analysis with Spirit's miniature thermal emission spectrometer. By using the rover's alpha particle X-ray spectrometer to collect data for multiple martian days, or sols, scientists are also beginning to get measurements of trace elements in the rocks. Spirit took the images that are combined into this mosaic on sol 358 (Jan. 3, 2005).

  11. Brushed Target on Rock 'Champagne' in Gusev Crater

    Science.gov (United States)

    2005-01-01

    NASA's Mars Exploration Rover Spirit took this microscopic image of a target called 'Bubbles' on a rock called 'Champagne' after using its rock abrasion tool to brush away a coating of dust. The circular brushed area is about 5 centimeters (2 inches) across. This rock is different from rocks out on the plains of Gusev Crater but is similar to other rocks in this area of the 'Columbia Hills' in that it has higher levels of phosphorus. Plagioclase, a mineral commonly found in igneous rocks, is also present in these rocks, according to analysis with the minature thermal emission spectrometer. By using the alpha particle X-ray spectrometer to collect data over multiple martian days, or sols, scientists are also beginning to get measurements of trace elements in these rocks. Spirit took the images that are combined into this mosaic on sol 354 (Dec. 30, 2004).

  12. Initial results from the Mini-TES experiment in Gusev Crater from the Spirit Rover

    Science.gov (United States)

    Christensen, P. R.; Ruff, S. W.; Fergason, R. L.; Knudson, A. T.; Anwar, S.; Arvidson, R. E.; Bandfield, J. L.; Blaney, D. L.; Budney, C.; Calvin, W. M.; hide

    2004-01-01

    The Miniature Thermal Emission Spectrometer (Mini-TES) on Spirit has studied the mineralogy and thermophysical properties at Gusev crater. Undisturbed soil spectra show evidence for minor carbonates and bound water. Rocks are olivinerich basalts with varying degrees of dust and other coatings. Dark-toned soils observed on disturbed surfaces may be derived from rocks and have derived mineralogy (+/-5 to 10%) of 45% pyroxene (20% Ca-rich pyroxene and 25% pigeonite), 40% sodic to intermediate plagioclase, and 15% olivine (forsterite 45% +/-5 to 10). Two spectrally distinct coatings are observed on rocks, a possible indicator of the interaction of water, rock, and airfall dust. Diurnal temperature data indicate particle sizes from 40 to 80 microm in hollows to approximately 0.5 to 3 mm in soils.

  13. Astrobiology and the Exploration of Gusev Crater by the Mars Exploration Rover Spirit

    Science.gov (United States)

    DesMarais, I. David

    2005-01-01

    We assess the availability of nutrient elements, energy and liquid water on the plains surrounding Columbia Memorial Station by evaluating data from Spirit in the context of previous Mars missions, Earth-based studies of martian meteorites and studies of microbial communities on Earth that represent potential analogs of martian biota. The compositions of Gusev basalts resemble those of olivine basalts beneath the seabed on Earth that deep drilling has shown to support life. Of particular relevance to biology, phosphate abundances are much greater in Gusev basalts (0.84 +/- 0.07 wt. % P2O5) than in oceanic basalts (typically 0.06 wt. %).

  14. Basalt-trachybasalt samples in Gale Crater, Mars

    International Nuclear Information System (INIS)

    Edwards, Peter H.; Anderson, Ryan B.; Dyar, Darby

    2017-01-01

    The ChemCam instrument on the Mars Science Laboratory (MSL) rover, Curiosity, observed numerous igneous float rocks and conglomerate clasts, reported previously. A new statistical analysis of single-laser-shot spectra of igneous targets observed by ChemCam shows a strong peak at ~55 wt% SiO 2 and 6 wt% total alkalis, with a minor secondary maximum at 47–51 wt% SiO 2 and lower alkali content. The centers of these distributions, together with the rock textures, indicate that many of the ChemCam igneous targets are trachybasalts, Mg# = 27 but with a secondary concentration of basaltic material, with a focus of compositions around Mg# = 54. We suggest that all of these igneous rocks resulted from low-pressure, olivine-dominated fractionation of Adirondack (MER) class-type basalt compositions. This magmatism has subalkaline, tholeiitic affinities. The similarity of the basalt endmember to much of the Gale sediment compositions in the first 1000 sols of the MSL mission suggests that this type of Fe-rich, relatively low-Mg#, olivine tholeiite is the dominant constituent of the Gale catchment that is the source material for the fine-grained sediments in Gale. The similarity to many Gusev igneous compositions suggests that it is a major constituent of ancient Martian magmas, and distinct from the shergottite parental melts thought to be associated with Tharsis and the Northern Lowlands. Finally, the Gale Crater catchment sampled a mixture of this tholeiitic basalt along with alkaline igneous material, together giving some analogies to terrestrial intraplate magmatic provinces.

  15. Moon/Mars Landing Commemorative Release: Gusev Crater and Ma'adim Vallis

    Science.gov (United States)

    1998-01-01

    On July 20, 1969, the first human beings landed on the Moon. On July 20, 1976, the first robotic lander touched down on Mars. This July 20th-- 29 years after Apollo 11 and 22 years since the Viking 1 Mars landing-- we take a look forward toward one possible future exploration site on the red planet.One of the advantages of the Mars Global Surveyor Mars Orbiter Camera (MOC) over its predecessors on the Viking and Mariner spacecraft is resolution. The ability to see-- resolve--fine details on the martian surface is key to planning future landing sites for robotic and, perhaps, human explorers that may one day visit the planet.At present, NASA is studying potential landing sites for the Mars Surveyor landers, rovers, and sample return vehicles that are scheduled to be launched in 2001, 2003, and 2005. Among the types of sites being considered for these early 21st Century landings are those with 'exobiologic potential'--that is, locations on Mars that are in some way related to the past presence of water.For more than a decade, two of the prime candidates suggested by various Mars research scientists are Gusev Crater and Ma'adim Vallis. Located in the martian southern cratered highlands at 14.7o S, 184.5o W, Gusev Crater is a large, ancient, meteor impact basin that--after it formed--was breached by Ma'adim Vallis.Viking Orbiter observations provided some evidence to suggest that a fluid--most likely, water--once flowed through Ma'adim Vallis and into Gusev Crater. Some scientists have suggested that there were many episodes of flow into Gusev Crater (as well as flow out of Gusev through its topographically-lower northwestern rim). Some have also indicated that there were times when Ma'adim Vallis, also, was full of water such that it formed a long, narrow lake.The possibility that water flowed into Gusev Crater and formed a lake has led to the suggestion that the materials seen on the floor of this crater--smooth-surfaced deposits, buried craters, and huge mesas near

  16. Astrobiology and the Basaltic Plains in Gusev Crater

    Science.gov (United States)

    DesMarais, D. J.; Clark, B. C.; Crumpler, L. S.; Farmer, J. D.; Grotzinger, John P.; Haskin, Larry A.; Knoll, Andrew H.; Landis, Geoffrey A.; Moersch, Jeffrey; Schroeder, Christian

    2005-01-01

    This report assesses the availability of nutrient elements, energy and liquid water on the plains surrounding Columbia Memorial Station by evaluating observations by the MER rover Spirit in the context of previous Mars missions, Earth-based studies of martian meteorites and studies of microbial communities on Earth that represent potential analogs of martian biota.

  17. Textures of the soils and rocks at Gusev crater from Spirit's Microscopic Imager

    DEFF Research Database (Denmark)

    Herkenhoff, K.E.; Squyres, S.W.; Arvidson, R.

    2004-01-01

    The Microscopic Imager on the Spirit rover analyzed the textures of the soil and rocks at Gusev crater on Mars at a resolution of 100 micrometers. Weakly bound agglomerates of dust are present in the soil near the Columbia Memorial Station. Some of the brushed or abraded rock surfaces show igneous...... textures and evidence for alteration rinds, coatings, and veins consistent with secondary mineralization. The rock textures are consistent with a volcanic origin and subsequent alteration and/or weathering by impact events, wind, and possibly water....

  18. Weathering Profiles in Phosphorus-Rich Rocks at Gusev Crater, Mars, Suggest Dissolution of Phosphate Minerals into Potentially Habitable Near-Neutral Waters.

    Science.gov (United States)

    Adcock, Christopher T; Hausrath, Elisabeth M

    2015-12-01

    Abundant evidence indicates that significant surface and near-surface liquid water has existed on Mars in the past. Evaluating the potential for habitable environments on Mars requires an understanding of the chemical and physical conditions that prevailed in such aqueous environments. Among the geological features that may hold evidence of past environmental conditions on Mars are weathering profiles, such as those in the phosphorus-rich Wishstone-class rocks in Gusev Crater. The weathering profiles in these rocks indicate that a Ca-phosphate mineral has been lost during past aqueous interactions. The high phosphorus content of these rocks and potential release of phosphorus during aqueous interactions also make them of astrobiological interest, as phosphorus is among the elements required for all known life. In this work, we used Mars mission data, laboratory-derived kinetic and thermodynamic data, and data from terrestrial analogues, including phosphorus-rich basalts from Idaho, to model a conceptualized Wishstone-class rock using the reactive transport code CrunchFlow. Modeling results most consistent with the weathering profiles in Wishstone-class rocks suggest a combination of chemical and physical erosion and past aqueous interactions with near-neutral waters. The modeling results also indicate that multiple Ca-phosphate minerals are likely in Wishstone-class rocks, consistent with observations of martian meteorites. These findings suggest that Gusev Crater experienced a near-neutral phosphate-bearing aqueous environment that may have been conducive to life on Mars in the past. Mars-Gusev Crater-Wishstone-Reactive transport modeling-CrunchFlow-Aqueous interactions-Neutral pH-Habitability.

  19. Determination of chemical composition of soils and rocks at the MER landing sites Gusev crater and Meridiani Planum using the APXS

    Science.gov (United States)

    Brueckner, J.

    2004-05-01

    The new Alpha Particle X-Ray Spectrometer (APXS) is a small, light-weight instrument to obtain x-ray spectra from Martian surface samples. The sensor head contains a high-resolution x-ray detector that is surrounded by a circle of radioactive Cm-244 sources. Alpha and x-ray radiation emitted by the sources is used to induce x-ray excitation in the sample. Elements from sodium to zinc (increasing by atomic weight) are detected and their concentrations determined. The APXS is mounted on each Instrument Deployment Device (IDD) of the two Mars Exploration Rovers (MER) Spirit and Opportunity. Rover Spirit landed in the large Gusev crater that seems to have been altered by water activities in the past based on evidence of orbital images. Rover Opportunity landed in a very small crater of the Meridiani Planum, where the mineral hematite that points to water-related processes is expected to be found. Inside the little crater, a light-colored outcrop is exposed that shows widespread fine layering. The first APXS high-resolution x-ray spectrum of a Gusev soil indicated many similarities to the composition of the Mars Pathfinder (MPF) and Viking soils. However, differences are also noticeable: Low-Z elements are somewhat higher compared to MPF soils, while high-Z elements are depleted, notably Ti. Potassium in the soils reflects the K concentration of the local rocks at the different landing sites pointing toward a local contribution to the soil's composition. The Rock Abrasion Tool was used to grind the first rock on Mars at Gusev: Adirondack's undisturbed and ground surface was measured by the APXS. The composition of its fresh surface is different from the MPF soilfree rock, noticeably in Mg and Al, and clearly exhibits a basaltic nature related to the composition of basaltic shergottites. The first rock at the Meridiani crater outcrop (dubbed Robert-E) exhibited a very high sulfur concentration, more than a factor of 15 compared to rock Adirondack, indicating it is

  20. Use of Geochemistry Data Collected by the Mars Exploration Rover Spirit in Gusev Crater to Teach Geomorphic Zonation through Principal Components Analysis

    Science.gov (United States)

    Rodrigue, Christine M.

    2011-01-01

    This paper presents a laboratory exercise used to teach principal components analysis (PCA) as a means of surface zonation. The lab was built around abundance data for 16 oxides and elements collected by the Mars Exploration Rover Spirit in Gusev Crater between Sol 14 and Sol 470. Students used PCA to reduce 15 of these into 3 components, which,…

  1. Petrogenesis of basalt-trachyte lavas from Olmoti Crater, Tanzania

    Science.gov (United States)

    Mollel, Godwin F.; Swisher, Carl C., III; McHenry, Lindsay J.; Feigenson, Mark D.; Carr, Michael J.

    2009-08-01

    Olmoti Crater is part of the Plio-Pleistocene Ngorongoro Volcanic Highland (NVH) in northern Tanzania to the south of Gregory Rift. The Gregory Rift is part of the eastern branch of the East African Rift System (EARS) that stretches some 4000 km from the Read Sea and Gulf of Aden in the north to the Zambezi River in Mozambique. Here, we (1) characterize the chemistry and mineral compositions of lavas from Olmoti Crater, (2) determine the age and duration of Olmoti volcanic activity through 40Ar/ 39Ar dating of Olmoti Crater wall lavas and (3) determine the genesis of Olmoti lavas and the relationship to other NVH and EARS volcanics and (4) their correlation with volcanics in the Olduvai and Laetoli stratigraphic sequences. Olmoti lavas collected from the lower part of the exposed crater wall section (OLS) range from basalt to trachyandesite whereas the upper part of the section (OUS) is trachytic. Petrography and major and trace element data reflect a very low degree partial melt origin for the Olmoti lavas, presumably of peridotite, followed by extensive fractionation. The 87Sr/ 86Sr data overlap whereas Nd and Pb isotope data are distinct between OLS and OUS samples. Interpretation of the isotope data suggests mixing of enriched mantle (EM I) with high-μ-like reservoirs, consistent with the model of Bell and Blenkinsop [Bell, K., Blenkinsop, J., 1987. Nd and Sr isotopic compositions of East African carbonatites: implications for mantle heterogeneity. Geology 5, 99-102] for East African carbonatite lavas. The isotope ratios are within the range of values defined by Oceanic Island Basalt (OIB) globally and moderate normalized Tb/Yb ratios (2.3-1.6) in these lavas suggest melting in the lithospheric mantle consistent with other studies in the region. 40Ar/ 39Ar incremental-heating analyses of matrix and anorthoclase separates from Olmoti OLS and OUS lavas indicate that volcanic activity was short in duration, lasting ˜200 kyr from 2.01 ± 0.03 Ma to 1.80 ± 0

  2. Sulfate Deposition in Regolith Exposed in Trenches on the Plains Between the Spirit Landing Site and Columbia Hills in Gusev Crater, Mars

    Science.gov (United States)

    Wang, Alian; Haskin, L. A.; Squyres, S. W.; Arvidson, R.; Crumpler, L.; Gellert, R.; Hurowitz, J.; Schroeder, C.; Tosca, N.; Herkenhoff, K.

    2005-01-01

    During its exploration within Gusev crater between sol 01 and sol 158, the Spirit rover dug three trenches (Fig. 1) to expose the subsurface regolith [1, 2, 9]. Laguna trench (approx. 6 cm deep, approx.203 m from the rim of Bonneville crater) was dug in Laguna Hollow at the boundary of the impact ejecta from Bonneville crater and the surrounding plains. The Big Hole trench (approx. 6-7 cm deep) and The Boroughs trench (approx. 11 cm deep) were dug in the plains between the Bonneville crater and the Columbia Hills (approx.556 m and approx.1698 m from the rim of Bonneville crater respectively). The top, wall and floor regolith of the three trenches were investigated using the entire set of Athena scientific instruments [10].

  3. Aqueous processes at Gusev crater inferred from physical properties of rocks and soils along the Spirit traverse

    Science.gov (United States)

    Cabrol, N.A.; Farmer, J.D.; Grin, E.A.; Ritcher, L.; Soderblom, L.; Li, R.; Herkenhoff, K.; Landis, G.A.; Arvidson, R. E.

    2006-01-01

    Gusev crater was selected as the landing site for Spirit on the basis of morphological evidence of long-lasting water activity, including possibly fluvial and lacustrine episodes. From the Columbia Memorial Station to the Columbia Hills, Spirit's traverse provides a journey back in time, from relatively recent volcanic plains showing little evidence for aqueous processes up to the older hills, where rock and soil composition are drastically different. For the first 156 sols, the only evidence of water action was weathering rinds, vein fillings, and soil crust cementation by salts. The trenches of Sols 112-145 marked the first significant findings of increased concentrations of sulfur and magnesium varying in parallel, suggesting that they be paired as magnesium-sulfate. Spirit's arrival at West Spur coincided with a shift in rock and soil composition with observations hinting at substantial amounts of water in Gusev's past. We used the Microscopic Imager data up to Sol 431 to analyze rock and soil properties and infer plausible types and magnitude of aqueous processes through time. We show the role played early by topography and structure. The morphology, texture, and deep alteration shown by the rocks in West Spur and the Columbia Hills Formation (CHF) suggest conditions that are not met in present-day Mars and required a wetter environment, which could have included transport of sulfur, chlorine, and bromine in water, vapor in volcanic gases, hydrothermal circulation, or saturation in a briny fluid containing the same elements. Changing conditions that might have affected flow circulation are suggested by different textural and morphological characteristics between the rocks in the CHF and those of the plains, with higher porosity proxy, higher void ratio, and higher water storage potential in the CHF. Soils were used to assess aqueous processes and water pathways in the top layers of modern soils. We conclude that infiltration might have become more difficult

  4. Curiosity at Gale Crater, Mars: Characterization and Analysis of the Rocknest Sand Shadow

    Science.gov (United States)

    Blake, D. F.; Morris, R. V.; Kocurek, G.; Morrison, S. M.; Downs, R. T.; Bish, D.; Ming, D. W.; Edgett, K. S.; Rubin, D.; Goetz, W.; Madsen, M. B.; Sullivan, R.; Gellert, R.; Campbell, I.; Treiman, A. H.; McLennan, S. M.; Yen, A. S.; Grotzinger, J.; Vaniman, D. T.; Chipera, S. J.; Achilles, C. N.; Rampe, E. B.; Sumner, D.; Meslin, P.-Y.; Maurice, S.; Forni, O.; Gasnault, O.; Fisk, M.; Schmidt, M.; Mahaffy, P.; Leshin, L. A.; Glavin, D.; Steele, A.; Freissinet, C.; Navarro-González, R.; Yingst, R. A.; Kah, L. C.; Bridges, N.; Lewis, K. W.; Bristow, T. F.; Farmer, J. D.; Crisp, J. A.; Stolper, E. M.; Des Marais, D. J.; Sarrazin, P.; Agard, Christophe; Alves Verdasca, José Alexandre; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Atreya, Sushil; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Blanco Avalos, Juan Jose; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Brinckerhoff, William; Brinza, David; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Cantor, Bruce; Caplinger, Michael; Rodríguez, Javier Caride; Carmosino, Marco; Blázquez, Isaías Carrasco; Charpentier, Antoine; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie; Juarez, Manuel de la Torre; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; Dietrich, William; Dingler, Robert; Donny, Christophe; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M. Darby; Edgar, Lauren; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fitzgibbon, Mike; Flesch, Greg; Floyd, Melissa; Flückiger, Lorenzo; Fraeman, Abby; Francis, Raymond; François, Pascaline; Franz, Heather; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Geffroy, Claude; Genzer, Maria; Godber, Austin; Goesmann, Fred; Golovin, Dmitry; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Jones, John; Joseph, Jonathan; Jun, Insoo; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Lepinette Malvitte, Alain; Léveillé, Richard; Lewin-Carpintier, Éric; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manning, Heidi; Marchand, Geneviève; Marín Jiménez, Mercedes; Martín García, César; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Mauchien, Patrick; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McNair, Sean; Melikechi, Noureddine; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Molina Jurado, Antonio; Moores, John; Mora-Sotomayor, Luis; Morookian, John Michael; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Muñoz Caro, Guillermo; Nachon, Marion; Navarro López, Sara; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Niles, Paul; Nixon, Brian; Dobrea, Eldar Noe; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; Owen, Tobias; Pablo, Hernández; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Pepin, Robert; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Robert, François; Rodriguez Manfredi, José Antonio; Romeral-Planelló, Julio J.; Rowland, Scott; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Sans Fuentes, Sara Alejandra; Saper, Lee; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Walter; Scholes, Daniel; Schoppers, Marcel; Schröder, Susanne; Sebastian Martinez, Eduardo; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sobrón Sánchez, Pablo; Spanovich, Nicole; Spray, John; Squyres, Steven; Stack, Katie; Stalport, Fabien; Stein, Thomas; Stern, Jennifer; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Sucharski, Bob; Summons, Roger; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge Loes; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Torres Redondo, Josefina; Trainer, Melissa; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Webster, Chris; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B.; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Zeitlin, Cary; Zimdar, Robert; Zorzano Mier, María-Paz

    2013-09-01

    The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. The fraction of sand Mars instrument and of the fine-grained nanophase oxide component first described from basaltic soils analyzed by MERs. The similarity between soils and aeolian materials analyzed at Gusev Crater, Meridiani Planum, and Gale Crater implies locally sourced, globally similar basaltic materials or globally and regionally sourced basaltic components deposited locally at all three locations.

  5. Characteristics, distribution, origin, and significance of opaline silica observed by the Spirit rover in Gusev crater, Mars

    Science.gov (United States)

    Ruff, S.W.; Farmer, J.D.; Calvin, W.M.; Herkenhoff, K. E.; Johnson, J. R.; Morris, R.V.; Rice, M.S.; Arvidson, R. E.; Bell, J.F.; Christensen, P.R.; Squyres, S. W.

    2011-01-01

    The presence of outcrops and soil (regolith) rich in opaline silica (???65-92 wt % SiO2) in association with volcanic materials adjacent to the "Home Plate" feature in Gusev crater is evidence for hydrothermal conditions. The Spirit rover has supplied a diverse set of observations that are used here to better understand the formation of silica and the activity, abundance, and fate of water in the first hydrothermal system to be explored in situ on Mars. We apply spectral, chemical, morphological, textural, and stratigraphic observations to assess whether the silica was produced by acid sulfate leaching of precursor rocks, by precipitation from silica-rich solutions, or by some combination. The apparent lack of S enrichment and the relatively low oxidation state of the Home Plate silica-rich materials appear inconsistent with the originally proposed Hawaiian analog for fumarolic acid sulfate leaching. The stratiform distribution of the silica-rich outcrops and their porous and brecciated microtextures are consistent with sinter produced by silica precipitation. There is no evidence for crystalline quartz phases among the silica occurrences, an indication of the lack of diagenetic maturation following the production of the amorphous opaline phase. Copyright ?? 2011 by the American Geophysical Union.

  6. Temperature dependence of the quadrupole splitting of olivine and pyroxene from the Plains of Gusev Crater on Mars

    International Nuclear Information System (INIS)

    Agresti, David G.

    2012-01-01

    In the present work, we report application of simultaneous fitting procedures to Mössbauer data acquired on the Plains of Gusev Crater by the MIMOS II spectrometer on board the Mars Exploration Rover Spirit. Based on a quantitative measure of spectrum quality, the 34 best of the ∼126 spectra acquired on the Plains are grouped together for a single simultaneous fit with a common least-squares criterion. Fitted values for the quadrupole splitting (QS) of olivine (Ol) from 200 K to 260 K are shown to lie between reported trend lines for Fo50 and Fo30 olivine, with a temperature gradient of (−11.2 ± 1.2) × 10  − 4 mm/s/K, a nearly five-fold improvement in precision over the previously reported value, enabling extrapolation to QS(Ol) = (2.93 ± 0.01) mm/s at 295 K. QS of pyroxene fit as a single doublet exhibits a temperature gradient of (−7.3 ± 2.3) × 10  − 4 mm/s/K.

  7. What We Might Know About Gusev Crater if the Mars Exploration Rover Spirit Mission were Coupled with a Mars Sample Return Mission

    Science.gov (United States)

    Morris, Richard V.

    2008-01-01

    The science instruments on the Mars Exploration Rover (MER) Spirit have provided an enormous amount of chemical and mineralogical data during more than 1450 sols of exploration at Gusev crater. The Moessbauer (MB) instrument identified 10 Fe-bearing phases at Gusev Crater: olivine, pyroxene, ilmenite, chromite, and magnetite as primary igneous phases and nanophase ferric oxide (npOx), goethite, hematite, a ferric sulfate, and pyrite/marcusite as secondary phases. The Miniature Thermal Emission Spectrometer (Mini-TES) identified some of these Fe-bearing phases (olivine and pyroxene), non- Fe-bearing phases (e.g., feldspar), and an amorphous high-SiO2 phase near Home Plate. Chemical data from the Alpha Particle X-Ray Spectrometer (APXS) provided the framework for rock classification, chemical weathering/alteration, and mineralogical constraints. APXS-based mineralogical constraints include normative calculations (with Fe(3+)/FeT from MB), elemental associations, and stoichiometry (e.g., 90% SiO2 implicates opalline silica). If Spirit had cached a set of representative samples and if those samples were returned to the Earth for laboratory analysis, what value is added by Mars Sample return (MSR) over and above the mineralogical and chemical data provided by MER?

  8. Discovery of Carbonate-Rich Outcrops in the Gusev Crater Columbia Hills by the MER Rover Spirit

    Science.gov (United States)

    Morris, Richard V.; Ruff, Steven W.; Gellert, Ralf; Ming, Douglas W.; Arvidson, Raymond E.; Clark, Benton C.; Golden, Dadi C.; Siebach, Kirsten L.; Klingelhoefer, Goestar; Schroeder, Christian; hide

    2010-01-01

    The chemical composition, global abundance, distribution, and formation pathways of carbonates are central to understanding aqueous processes, climate, and habitability of early Mars. The Mars Exploration Rover (MER) Spirit analyzed a series of olivine-rich outcrops while descending from the summit region of Husband Hill into the Inner Basin of the Columbia Hills of Gusev Crater to the eastern edge of the El Dorado ripple field in late 2005. Reanalysis of Spirit s mineralogical data from the Moessbauer Spectrometer (MB) and the Miniature Thermal Emission Spectrometer (Mini-TES) and chemical data from the Alpha Particle X-Ray Spectrometer (APXS) in 2010, coupled with new laboratory data for carbonate-bearing samples, lead to identification of carbonate in one of the outcrops (Comanche) [Morris, R.V., et al., Science, 329, 421-424]. The carbonate is rich in magnesium and iron (Mc62Sd25Cc11Rh2, assuming all Ca and Mn is associated with the carbonate) and is a major component of the Comanche outcrops (16 to 34 wt.%). The mineralogical, chemical, and abundance data are constrained in multiple, mutually consistent ways by the MER analyses. For example, a low-Ca carbonate is required by the MB and APXS data and is consistent with Mini-TES data. Three spectral features attributable to fundamental infrared vibrational modes of low-Ca carbonate are present in the Mini-TES spectra of Comanche outcrops. The average composition of Comanche carbonate approximates the average composition of the carbonate globules in Martian meteorite ALH 84001. Analogy with ALH 84001, terrestrial, and synthetic carbonate globules suggests that Comanche carbonate precipitated from aqueous solutions under hydrothermal conditions at near neutral pH in association with volcanic activity during the Noachian era. Comanche outcrop morphology suggests they are remnants of a larger carbonate-bearing formation that evolved in ultramafic rock and then preferentially eroded by a combination of aeolian

  9. Mid-IR Reflectance (DRIFT) Spectral Variations in Basaltic Mineralogy with Direction of Impact at Lonar Crater, India

    Science.gov (United States)

    Basavaiah, N.; Chavan, R. S.; Arif, M.

    2012-12-01

    Identification of spectral changes with the direction of impact has important implications for understanding the impact cratering phenomenon occurring on both terrestrial and extraterrestrial planets and also for geology of the crater. Fortuitously, Lonar Impact Crater (India) is the only well-preserved terrestrial simple crater excavated on Deccan basalts and serves as an excellent analogue to craters on Mars and Moon. An ~570 ka old Lonar crater was suggested to be formed by an oblique impact of a chondritic impactor that struck the pre-impact target from the east into a sequence of six basaltic Deccan flows and created a 1.88 km diameter crater with two layers of ejecta blanket. Here we report preliminary laboratory studies of spectral results on fine-grained rock powers (IR (4000-400 cm-1) Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy. The basalts were collected from two profiles in the east and south sections of the crater wall and the upper most crater rim, which later subdivided into sector-wise samples to carry out a systematic study of spectral properties of Lonar basalts, together with impact related samples of breccias and impact melts. For the first time, data of the shock metamorphism of Lonar basalt is examined using DRIFT spectroscopy. Infrared spectra of rock powders of relatively unshocked and shocked basalts are obtained to document the mineralogical variations and the distribution of primary (e.g. Plagioclase Feldspar, Pyroxene), and secondary Phyllosilicate minerals (e.g. Illite, Smectite, Montmorillonite, Saponite, Serpentine) with direction of impact. The spectral data between pre-impact unshocked and post-impact shocked basalts are interpreted to reflect the effect of shock pressure and alteration that rock have undergone. On western crater rim sector, typical silicate spectral features in 900-1200 cm-1 which attributed to Si-O stretching, are observed to change slightly in the width and shift in position as a result of

  10. Geology of Pine and Crater Buttes: two basaltic constructs on the far eastern Snake River Plain

    International Nuclear Information System (INIS)

    Mazierski, P.F.; King, J.S.

    1987-01-01

    The emplacement history and petrochemical evolution of the volcanics associated with Pine Butte, Crater Butte, and other nearby vents are developed and described. Four major vents were identified in the study area and their associated eruptive products were mapped. All of the vents show a marked physical elongation or linear orientation coincident with the observed rift set. Planetary exploration has revealed the importance of volcanic processes in the genesis and modification of extraterrestrial surfaces. Interpretation of surface features has identified plains-type basaltic volcanism in various mare regions of the Moon and the volcanic provinces of Mars. Identification of these areas with features that appear analogous to those observed in the Pine Butte area suggests similar styles of eruption and mode of emplacement. Such terrestrial analogies serve as a method to interpret the evolution of volcanic planetary surfaces on the inner planets

  11. Basaltic caves at Craters of the Moon National Monument and Preserve as analogs for Mars

    Science.gov (United States)

    Hinman, N. W.; Richardson, C. D.; McHenry, L.; Scott, J. R.

    2010-12-01

    Basaltic caves and lava tubes offer stable physicochemical conditions for formation of secondary minerals. Such features, putatively observed on Mars, intercept groundwater to weather country rock, leading to formation of secondary minerals. Further, caves are stable environments to search for evidence of past life, as they could offer protection from the oxidizing martian atmosphere. Searching for signs of life in a cave that could protect bio/organic compounds would preclude the need for risky drilling on Mars. Craters of the Moon National Monument (COM) offers an opportunity to study caves in Holocene iron-rich basalt flows to characterize secondary mineral deposits and search for organic compounds associated with secondary minerals; COM basalts are a good analog for martian basalts because of their high iron but other elements are higher at COM than on Mars. The Blue Dragon flow (~2.1 ka) contains the majority of the accessible caves and lava tubes. Two types of secondary mineral deposits were observed in these caves: ceiling coatings and crack or floor precipitates. Hematite, silica, and calcite comprise ceiling coatings. The crack and floor precipitates are white, efflorescent deposits in cavities along cave walls and ceilings or in localized mounds on cave floors. The secondary minerals in crack and floor precipitates are mainly thenardite and mirabilite with some minor concentrations of trona and/or burkeite. Organic compounds were found associated with the efflorescent deposits. Formation of the deposits is likely due to chemical leaching of basalt by meteoritic water. To test this, fluids collected from the ceiling and walls of the caves were analyzed. Solutions were modeled with the geochemical code, PHREEQC. The model tracked composition as water evaporated. Selected minerals were allowed to precipitate as they became oversaturated. Among the first minerals to become oversaturated were quartz and calcite, which are observed in ceiling deposits. Iron

  12. Comparison of some Phoenix and gusev soil types

    DEFF Research Database (Denmark)

    Walter..[], Goetz; Hviid, S.F.; Madsen, Morten Bo

    2010-01-01

    The comparison of soil particles at the Phoenix landing site and in Gusev Crater provides clues on their origin and global distribution. Some unusual Phoenix particles are possibly of (more) local origin, as they appear to be absent in Gusev dunes....

  13. Sunset Crater, AZ: Evolution of a highly explosive basaltic eruption as indicated by granulometry and clast componentry

    Science.gov (United States)

    Allison, C. M.; Clarke, A. B.; Pioli, L.; Alfano, F.

    2011-12-01

    Basaltic scoria cone volcanoes are the most abundant volcanic edifice on Earth and occur in all tectonic settings. Basaltic magmas have lower viscosities, higher temperatures, and lower volatile contents than silicic magmas, and therefore generally have a lower potential for explosive activity. However, basaltic eruptions display great variability in eruptive style, from mild lava flows to more energetic explosions with large plumes. The San Francisco Volcanic Field (SFVF) in northern Arizona, active from 6 Ma-present, consists of over 600 volcanoes, mostly alkali basalt scoria cones, and five silicic centers [Wood and Kienle (1990), Cambridge University Press]. The eruption of Sunset Crater in the SFVF during the Holocene was an anomalously large basaltic explosive eruption, consisting of eight tephra-bearing phases and three lava flows [Amos (1986), MS thesis, ASU]. Typical scoria cone-forming eruptions have volumes sorted. Future work will include textural analysis of bubbles and crystals to understand the ascent and cooling history of the different clast types, and also to better interpret differences in abundance as related to variations in eruption or vent dynamics.

  14. Secondary Sulfate Mineralization and Basaltic Chemistry of Craters of the Moon National Monument, Idaho: Potential Martian Analog

    Energy Technology Data Exchange (ETDEWEB)

    C. Doc Richardson; Nancy W. Hinman; Lindsay J. McHenry; J. Michelle Kotler; Jill R. Scott

    2012-05-01

    Secondary deposits associated with the basaltic caves of Craters of the Moon National Monument (COM) in southern Idaho were examined using X-ray powder diffraction, X-ray fluorescence spectrometry, Fourier transform infrared spectrometry, and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The secondary mineral assemblages are dominated by Na-sulfate minerals (thenardite, mirabilite) with a small fraction of the deposits containing minor concentrations of Na-carbonate minerals. The assemblages are found as white, efflorescent deposits in small cavities along the cave walls and ceilings and as localized mounds on the cave floors. Formation of the deposits is likely due to direct and indirect physiochemical leaching of meteoritic water through the overlying basalts. Whole rock data from the overlying basaltic flows are characterized by their extremely high iron concentrations, making them good analogs for martian basalts. Understanding the physiochemical pathways leading to secondary mineralization at COM is also important because lava tubes and basaltic caves are present on Mars. The ability of FTICR-MS to consistently and accurately identify mineral species within these heterogeneous mineral assemblages proves its validity as a valuable technique for the direct fingerprinting of mineral species by deductive reasoning or by comparison with reference spectra.

  15. Geology and petrology of the basalts of Crater Flat: applications to volcanic risk assessment for the Nevada Nuclear Waste Storage investigations

    International Nuclear Information System (INIS)

    Vaniman, D.; Crowe, B.

    1981-06-01

    Volcanic hazard studies of the south-central Great Basin, Nevada, are being conducted for the Nevada Nuclear Waste Storage Investigations. This report presents the results of field and petrologic studies of the basalts of Crater Flat, a sequence of Pliocene to Quaternary-age volcanic centers located near the southwestern part of the Nevada Test Site. Crater Flat is one of several basaltic fields constituting a north-northeast-trending volcanic belt of Late Cenozoic age extending from southern Death Valley, California, through the Nevada Test Site region to central Nevada. The basalts of Crater Flat are divided into three distinct volcanic cycles. The cycles are characterized by eruption of basalt magma of hawaiite composition that formed cinder cone clusters and associated lava flows. Total volume of erupted magma for respective cycles is given. The basalts of Crater Flat are sparsely to moderately porphyritic; the major phenocryst phase is olivine, with lesser amounts of plagioclase, clinopyroxene, and rare amphibole. The consistent recurrence of evolved hawaiite magmas in all three cycles points to crystal fractionation from more primitive magmas at depth. A possible major transition in mantle source regions through time may be indicated by a transition from normal to Rb-depleted, Sr-enriched hawaiites in the younger basaltic cycles. The recurrence of small volumes of hawaiite magma at Crater Flat supports assumptions required for probability modeling of future volcanic activity and provides a basis for estimating the effects of volcanic disruption of a repository site in the southwestern Nevada Test Site region. Preliminary data suggest that successive basalt cycles at Crater Flat may be of decreasing volume but recurring more frequently

  16. Curiosity at Gale Crater, Mars: Characterization and Analysis of the Rocknest Sand Shadow

    Science.gov (United States)

    Blake, David F.; Morris, Richard V.; Kocurek, G.; Morrison, S. M.; Downs, R. T.; Bish, D.; Ming, D. W.; Edgett, K. S.; Rubin, D.; Goetz, W.; hide

    2013-01-01

    The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MER) Spirit and Opportunity. The fraction of sand <150 micron in size contains approx. 55% crystalline material consistent with a basaltic heritage, and approx. 45% X-ray amorphous material. The amorphous component of Rocknest is Fe-rich and Si-poor, and is the host of the volatiles (H2O, O2, SO2, CO2, and Cl) detected by the Surface Analysis at Mars (SAM) instrument and of the fine-grained nanophase oxide (npOx) component first described from basaltic soils analyzed by MER. The similarity between soils and aeolian materials analyzed at Gusev crater, Meridiani Planum and Gale crater implies locally sourced, globally similar basaltic materials, or globally and regionally sourced basaltic components deposited locally at all three locations.

  17. Initial Results on the Mineralogy and Geochemistry of the Mar Exploration Rover Gusev Landing Site

    Science.gov (United States)

    Christensen, P. R.

    2004-05-01

    The Spirit rover has investigated the geochemistry and mineralogy of the Gusev crater site using in situ Alpha Proton X-Ray, Mossbauer, visible, and infrared spectroscopy. The Gusev site is covered with angular to sub-rounded rocks that are typically less than 1 m in maximum dimension. More than 90 percent of these rocks are dark-toned, with the remainder being lighter-toned rocks that may predominantly be dark rocks with a thin (10's of microns) coating of easily removed fines. APXS analysis has been obtained of a rock (Adirondack) following the removal by grinding of the surface dust and the upper few mm of the rock surface. These data give a modal mineralogy corresponding to olivine basalt. High quality Mini-TES data have not been obtained of a completely dust-free rock surface. The Mini-TES data of Adirondack do show long wavelength (15-25 microns) absorptions due to olivine of composition ~Fo60. All of the rocks observed are very compositionally homogeneous in the Mini-TES spectra. These findings are consistent with the detection of olivine-bearing basalt at this site from orbital TES infrared spectroscopy. Mossbauer spectra of Adirondack show the presence of forsteritic olivine and magnetite, with possible pyroxene. The soils at Gusev are a mixture of reddish fine-grained to sandy materials, granular-sized particles that occur in ripple forms, and minor pebbles. Mini-TES spectra of the soil show an excellent match to the TES spectra of high-albedo, fine-grained material found in regional bright regions that is interpreted to be windblown dust. This agreement suggests at least the uppermost layer of the soil at Gusev has been accumulated from airfall dust. By analogy with prior analysis of TES data these materials contain several percent carbonate, minor bound water, and a framework silicate interpreted to be either feldspar or zeolite. APXS spectra show similar oxide abundances to those determined for the Pathfinder site, except for higher MgO, and lower

  18. The geology of Pine and Crater Buttes: Two basaltic constructs on the far eastern Snake River Plain

    Science.gov (United States)

    Mazierski, Paul F.; King, John S.

    1987-01-01

    The emplacement history and petrochemical evolution of the volcanics associated with Pine Butte, Crater Butte, and other nearby vents are developed and described. Four major vents were identified in the study area and their associated eruptive products were mapped. All of the vents show a marked physical elongation or linear orientation coincident with the observed rift set. Planetary exploration has revealed the importance of volcanic processes in the genesis and modification of extraterrestrial surfaces. Interpretation of surface features has identified plains-type basaltic volcanism in various mare regions of the Moon and the volcanic provinces of Mars. Identification of these areas with features that appear analogous to those observed in the Pine Butte area suggests similar styles of eruption and mode of emplacement. Such terrestrial analogies serve as a method to interpret the evolution of volcanic planetary surfaces on the inner planets.

  19. X-ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest at Gale Crater

    Science.gov (United States)

    Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Morris, R. V.; Ming, D. W.; Treiman, A. H.; Sarrazin, P.; Morrison, S. M.; Downs, R. T.; Achilles, C. N.; Yen, A. S.; Bristow, T. F.; Crisp, J. A.; Morookian, J. M.; Farmer, J. D.; Rampe, E. B.; Stolper, E. M.; Spanovich, N.; Achilles, Cherie; Agard, Christophe; Verdasca, José Alexandre Alves; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Atreya, Sushil; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Bish, David; Blake, David F.; Avalos, Juan J. Blanco; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John "Iain"; Cantor, Bruce; Caplinger, Michael; Rodríguez, Javier Caride; Carmosino, Marco; Blázquez, Isaías Carrasco; Charpentier, Antoine; Chipera, Steve; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Crisp, Joy; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie "Kenzie"; Juarez, Manuel de la Torre; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; DesMarais, David; Dietrich, William; Dingler, Robert; Donny, Christophe; Downs, Bob; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M. Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Flesch, Greg; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; François, Pascaline; Franz, Heather; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Jones, John; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Malvitte, Alain Lepinette; Leshin, Laurie; Léveillé, Richard; Lewin-Carpintier, Éric; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Mahaffy, Paul; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gérard; Manning, Heidi; Marchand, Geneviève; Jiménez, Mercedes Marín; García, César Martín; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Mauchien, Patrick; Maurice, Sylvestre; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McLennan, Scott; McNair, Sean; Melikechi, Noureddine; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Ming, Douglas; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Jurado, Antonio Molina; Moores, John; Mora-Sotomayor, Luis; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Caro, Guillermo Muñoz; Nachon, Marion; López, Sara Navarro; Navarro-González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Niles, Paul; Nixon, Brian; Dobrea, Eldar Noe; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; Owen, Tobias; Hernández, Miguel Ángel de Pablo; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Pepin, Robert; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Rampe, Elizabeth; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Robert, François; Robertson, Kevin; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio J.; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Fuentes, Sara Alejandra Sans; Saper, Lee; Sarrazin, Philippe; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel "Dan"; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne; Martinez, Eduardo Sebastian; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sánchez, Pablo Sobrón; Spanovich, Nicole; Spray, John; Squyres, Steven; Stack, Katie; Stalport, Fabien; Steele, Andrew; Stein, Thomas; Stern, Jennifer; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Stolper, Ed; Sucharski, Bob; Sullivan, Rob; Summons, Roger; Sumner, Dawn; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Redondo, Josefina Torres; Trainer, Melissa; Treiman, Allan; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Vaniman, David; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Webster, Chris; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B. "Mouser"; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Yen, Albert; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Mier, María-Paz Zorzano

    2013-09-01

    The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian bedform in Gale crater. Analysis of the soil with the Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite, and pigeonite, with minor K-feldspar, magnetite, quartz, anhydrite, hematite, and ilmenite. The minor phases are present at, or near, detection limits. The soil also contains 27 ± 14 weight percent x-ray amorphous material, likely containing multiple Fe3+- and volatile-bearing phases, including possibly a substance resembling hisingerite. The crystalline component is similar to the normative mineralogy of certain basaltic rocks from Gusev crater on Mars and of martian basaltic meteorites. The amorphous component is similar to that found on Earth in places such as soils on the Mauna Kea volcano, Hawaii.

  20. Exploration of microbial diversity and community structure of Lonar Lake: the only hypersaline meteorite crater lake within basalt rock

    Directory of Open Access Journals (Sweden)

    Dhiraj ePaul

    2016-01-01

    Full Text Available Lonar Lake is a hypersaline and hyperalkaline soda lake and the only meteorite impact crater in the world created in the basalt rocks. Although culture-dependent studies have been reported, the comprehensive understanding of microbial community composition and structure of Lonar Lake remain obscure. In the present study, microbial community structure associated with Lonar Lake sediment and water samples was investigated using high throughput sequencing. Microbial diversity analysis revealed the existence of diverse, yet near consistent community composition. The predominance of bacterial phyla Proteobacteria (30% followed by Actinobacteria (24%, Firmicutes (11% and Cyanobacteria (5% was observed. Bacterial phylum Bacteroidetes (1.12%, BD1-5 (0.5%, Nitrospirae (0.41% and Verrucomicrobia (0.28% were detected as relatively minor populations in Lonar Lake ecosystem. Within Proteobacteria, Gammaproteobacteria represented the most abundant population (21-47% among all the sediments and as a minor population in water samples. Bacterial members Proteobacteria and Firmicutes were present significantly higher (p≥0.05 in sediment samples, whereas members of Actinobacteria, Candidate_division_TM7 and Cyanobacteria (p≥0.05 were significantly abundant in water samples. It was noted that compared to other hypersaline soda lakes, Lonar Lake samples formed one distinct cluster, suggesting a different microbial community composition and structure. The present study reports for the first time the different composition of indigenous microbial communities between the sediment and water samples of Lonar Lake. Having better insight of community structure of this Lake ecosystem could be useful in understanding the microbial role in the geochemical cycle for future functional exploration of the unique hypersaline Lonar Lake.

  1. Mineralogy, provenance, and diagenesis of a potassic basaltic sandstone on Mars: CheMin X-ray diffraction of the Windjana sample (Kimberley area, Gale Crater)

    International Nuclear Information System (INIS)

    Treiman, Allan H.; Bish, David L.; Chipera, Steve J.; Blake, David F.

    2015-01-01

    The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X-ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or 95 ); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X-ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser-Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K-rich targets have 5.6% K 2 O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na 2 O, and is likely to be basaltic. The K-rich sediment component is consistent with APXS and ChemCam observations of K-rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. Finally, the presence of sediment from many igneous sources, in concert with Curiosity's identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar-age terranes on Earth.

  2. Magma genesis at Gale Crater: Evidence for Pervasive Mantle Metasomatism

    Science.gov (United States)

    Filiberto, J.

    2017-12-01

    Basaltic rocks have been analyzed at Gale Crater with a larger range in bulk chemistry than at any other landing site [1]. Therefore, the rocks may have experienced significantly different formation conditions than those experienced by magmas at Gusev Crater or Meridiani Planum. Specifically, the rocks at Gale Crater have higher potassium than other Martian rocks, with a potential analog of the Nakhlite parental magma, and are consistent with forming from a metasomatized mantle source [2-4]. Mantle metasomatism would not only affect the bulk chemistry but mantle melting conditions, as metasomatism fluxes fluids into the source region. Here I will combine differences in bulk chemistry between Martian basalts to calculate formation conditions in the interior and investigate if the rocks at Gale Crater experienced magma genesis conditions consistent with metasomatism - lower temperatures and pressures of formation. To calculate average formation conditions, I rely on experimental results, where available, and silica-activity and Mg-exchange thermometry calculations for all other compositions following [5, 6]. The results show that there is a direct correlation between the calculated mantle potential temperature and the K/Ti ratio of Gale Crater rocks. This is consistent with fluid fluxed metasomatism introducing fluids to the system, which depressed the melting temperature and fluxed K but not Ti to the system. Therefore, all basalts at Gale Crater are consistent with forming from a metasomatized mantle source, which affected not only the chemistry of the basalts but also the formation conditions. References: [1] Cousin A. et al. (2017) Icarus. 288: 265-283. [2] Treiman A.H. et al. (2016) Journal of Geophysical Research: Planets. 121: 75-106. [3] Treiman A.H. and Medard E. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10.1130/abs/2016AM-285851. [4] Schmidt M.E. et al. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10

  3. Smectite Formation from Basaltic Glass Under Acidic Conditions on Mars

    Science.gov (United States)

    Peretyazhko, T. S.; Sutter, B.; Morris, R. V.; Agresti, D. G.; Le, L.; Ming, D. W.

    2015-01-01

    Massive deposits of phyllosilicates of the smectite group, including Mg/Fe-smectite, have been identified in Mars's ancient Noachian terrain. The observed smectite is hypothesized to form through aqueous alteration of basaltic crust under neutral to alkaline pH conditions. These pH conditions and the presence of a CO2-rich atmosphere suggested for ancient Mars were favorable for the formation of large carbonate deposits. However, the detection of large-scale carbonate deposits is limited on Mars. We hypothesized that smectite deposits may have formed under acidic conditions that prevented carbonate precipitation. In this work we investigated formation of saponite at a pH of approximately 4 from Mars-analogue synthetic Adirondack basaltic glass of composition similar to Adirondack class rocks located at Gusev crater. Hydrothermal (200º Centigrade) 14 day experiments were performed with and without 10 millimoles Fe(II) or Mg under anoxic condition [hereafter denoted as anoxic_Fe, anoxic_Mg and anoxic (no addition of Fe(II) or Mg)] and under oxic condition [hereafter denoted as oxic (no addition of Fe(II) or Mg)]. Characterization and formation conditions of the synthesized saponite provided insight into the possible geochemical conditions required for saponite formation on Mars.

  4. APXS-derived chemistry of the Bagnold dune sands: Comparisons with Gale Crater soils and the global Martian average

    Science.gov (United States)

    O'Connell-Cooper, C. D.; Spray, J. G.; Thompson, L. M.; Gellert, R.; Berger, J. A.; Boyd, N. I.; Desouza, E. D.; Perrett, G. M.; Schmidt, M.; VanBommel, S. J.

    2017-12-01

    We present Alpha-Particle X-ray Spectrometer (APXS) data for the active Bagnold dune field within the Gale impact crater (Mars Science Laboratory (MSL) mission). We derive an APXS-based average basaltic soil (ABS) composition for Mars based on past and recent data from the MSL and Mars Exploration Rover (MER) missions. This represents an update to the Taylor and McLennan (2009) average Martian soil and facilitates comparison across Martian data sets. The active Bagnold dune field is compositionally distinct from the ABS, with elevated Mg, Ni, and Fe, suggesting mafic mineral enrichment and uniformly low levels of S, Cl, and Zn, indicating only a minimal dust component. A relationship between decreasing grain size and increasing felsic content is revealed. The Bagnold sands possess the lowest S/Cl of all Martian unconsolidated materials. Gale soils exhibit relatively uniform major element compositions, similar to Meridiani Planum and Gusev Crater basaltic soils (MER missions). However, they show minor enrichments in K, Cr, Mn, and Fe, which may signify a local contribution. The lithified eolian Stimson Formation within the Gale impact crater is compositionally similar to the ABS and Bagnold sands, which provide a modern analogue for these ancient eolian deposits. Compilation of APXS-derived soil data reveals a generally homogenous global composition for Martian soils but one that can be locally modified due to past or extant geologic processes that are limited in both space and time.

  5. Mars on Earth: Analog basaltic soils and particulates from Lonar Crater, India, include Deccan soil, shocked soil, reworked lithic and glassy ejecta, and both shocked and unshocked baked zones

    Science.gov (United States)

    Wright, S. P.

    2017-12-01

    "There is no perfect analog for Mars on Earth" [first line of Hipkin et al. (2013) Icarus, 261-267]. However, fieldwork and corresponding sample analyses from laboratory instrumentation (to proxy field instruments) has resulted in the finding of unique analog materials that suggest that detailed investigations of Lonar Crater, India would be beneficial to the goals of the Mars Program. These are briefly described below as Analog Processes, Materials, and Fieldwork. Analog Processes: The geologic history of Lonar Crater emulates localities on Mars with 1.) flood basaltic volcanism with interlayer development of 2.) baked zones or "boles" and 3.) soil formation. Of six flows, the lower three are aqueously altered by groundwater to produce a range of 4.) alteration products described below. The impact event 570 ka produced a range of 5.) impactites including shocked baked zones, shocked soils, and altered basalt shocked to a range of shock pressures [Kieffer et al., 1976]. Analog Materials: 65 Ma Deccan basalt contains augite and labradorite. Baked zones are higher in hematite and other iron oxides. Soil consists of calcite and organic matter. Several basalts with secondary alteration are listed here and these mirror alteration on Mars: hematite, chlorite, serpentine, zeolite, and palagonite, with varying combinations of these with primary igneous minerals. All of these materials (#1 through 4 above) are shocked to a range of shocked pressures to produce maskelynite, flowing plagioclase glass, vesiculated plagioclase glass, and complete impact melts. Shocked soils contain schlieren calcite amidst comminuted grains of augite, labradorite, and these glasses. Shocked baked zones unsurprisingly have a petrographic texture similar to hornfels, another product of contact metamorphism. Analog Fieldwork: The ejecta consists of two layers: 8 m of lithic breccia with unshocked and fractured basalts under a 1 m suevite consisting of all ranges of shock pressure described above

  6. Hypervelocity impact cratering calculations

    Science.gov (United States)

    Maxwell, D. E.; Moises, H.

    1971-01-01

    A summary is presented of prediction calculations on the mechanisms involved in hypervelocity impact cratering and response of earth media. Considered are: (1) a one-gram lithium-magnesium alloys impacting basalt normally at 6.4 km/sec, and (2) a large terrestrial impact corresponding to that of Sierra Madera.

  7. Drainage systems of Lonar Crater, India: Contributions to Lonar Lake hydrology and crater degradation

    Science.gov (United States)

    Komatsu, Goro; Senthil Kumar, P.; Goto, Kazuhisa; Sekine, Yasuhito; Giri, Chaitanya; Matsui, Takafumi

    2014-05-01

    Lonar, a 1.8-km-diameter impact crater in India, is a rare example of terrestrial impact craters formed in basaltic bedrock. The estimated age of the crater ranges widely from less than 12 ka to over 600 ka, but the crater preserves a relatively pristine morphology. We conducted a study of various drainage systems of Lonar Crater. The crater floor hosts a shallow 5-m-deep lake, which fluctuates seasonally. Our investigation reveals that the lake level is influenced by surface runoff that is active during the monsoon and groundwater input effective during both the rainy and the dry seasons. The groundwater discharge is observed as springs on the inner rim walls corresponding to weathered vesicular basalt and/or proximal ejecta, which are underlain by thick massive basalt layers. This observation indicates that groundwater movement is lithologically controlled: it passes preferentially through permeable vesicular basalt or proximal ejecta but is hindered in less permeable massive basalt. It is hypothesized that groundwater is also structurally controlled by dipping of basalt layers, interconnectivity of the permeable lithologic units through fractures, and preferential pathways such as fractures within the permeable lithologic units. Investigation on hydrological processes at Lonar Crater and its lake could provide useful insights into purported paleo-crater lakes presumably formed in the basaltic crust of Mars. The Lonar Crater interior shows signs of degradation in the forms of gullies and debris flows, and the Dhar valley incising in the rim leading to form a fan delta. The ejecta surface is characterized by the presence of channels, originating from the rim area and extending radially away from the crater center. The channels probably resulted from surface runoff, and its erosion contributes to the removal of the ejecta. Lonar Crater is a valuable analog site for studying degradation processes with potential application to impact craters occurring on

  8. Blocky craters: implications about the lunar megaregolith

    International Nuclear Information System (INIS)

    Thompson, T.W.; Roberts, W.J.; Hartmann, W.K.; Shorthill, R.W.; Zisk, S.H.

    1979-01-01

    Radar, infrared, and photogeologic properties of lunar craters have been studied to determine whether there is a systematic difference in blocky craters between the maria and terrae and whether this difference may be due to a deep megaregolith of pulverized material forming the terra surface, as opposed to a layer of semi-coherent basalt flows forming the mare surface. Some 1310 craters from about 4 to 100 km diameter have been catalogued as radar and/or infrared anomalies. In addition, a study of Apollo Orbital Photography confirmed that the radar and infrared anomalies are correlated with blocky rubble around the crater. Analysis of the radar and infrared data indicated systematic terra-mare differences. Fresh terra craters smaller than 12 km were less likely to be infrared and radar anomalies than comparable mare craters: but terra and mare craters larger than 12 km had similar infrared and radar signatures. Also, there are many terra craters which are radar bright but not infrared anomalies. The authors interpretation of these data is that while the maria are rock layers (basaltic flow units) where craters eject boulder fields, the terrae are covered by relatively pulverized megaregolith at least 2 km deep, where craters eject less rocky rubble. Blocky rubble, either in the form of actual rocks or partly consolidated blocks, contributes to the radar and infrared signatures of the crater. However, aging by impacts rapidly destroys these effects, possibly through burial by secondary debris or by disintegration of the blocks themselves, especially in terra regions. (Auth.)

  9. How old is Autolycus crater?

    Science.gov (United States)

    Hiesinger, Harald; Pasckert, Jan Henrik; van der Bogert, Carolyn H.; Robinson, Mark S.

    2016-04-01

    Accurately determining the lunar cratering chronology is prerequisite for deriving absolute model ages (AMAs) across the lunar surface and throughout the Solar System [e.g., 1]. However, the lunar chronology is only constrained by a few data points over the last 1 Ga and there are no calibration data available between 1 and 3 Ga and beyond 3.9 Ga [2]. Rays from Autolycus and Aristillus cross the Apollo 15 landing site and presumably transported material to this location [3]. [4] proposed that at the Apollo 15 landing site about 32% of any exotic material would come from Autolycus crater and 25% would come from Aristillus crater. [5,6] proposed that the 39Ar-40Ar age of 2.1 Ga derived from three petrologically distinct, shocked Apollo 15 KREEP basalt samples, date Autolycus crater. Grier et al. [7] reported that the optical maturity (OMAT) characteristics of these craters are indistinguishable from the background values despite the fact that both craters exhibit rays that were used to infer relatively young, i.e., Copernican ages [8,9]. Thus, both OMAT characteristics and radiometric ages of 2.1 Ga and 1.29 Ga for Autolycus and Aristillus, respectively, suggest that these two craters are not Copernican in age. [10] interpreted newer U-Pb ages of 1.4 and 1.9 Ga from sample 15405 as the formation ages of Aristillus and Autolycus. If Autolycus is indeed the source of the dated exotic material collected at the Apollo 15 landing site, than performing crater size frequency distribution (CSFD) measurements for Autolycus offers the possibility to add a new calibration point to the lunar chronology, particularly in an age range that was previously unconstrained. We used calibrated and map-projected LRO NAC images to perform CSFD measurements within ArcGIS, using CraterTools [11]. CSFDs were then plotted with CraterStats [12], using the production and chronology functions of [13]. We determined ages of 3.72 and 3.85 Ga for the interior (Ai1) and ejecta area Ae3, which we

  10. Nuclear cratering on a digital computer

    Energy Technology Data Exchange (ETDEWEB)

    Terhune, R W; Stubbs, T F; Cherry, J T [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    Computer programs based on the artificial viscosity method are applied to developing an understanding of the physics of cratering, with emphasis on cratering by nuclear explosives. Two established codes, SOC (spherical symmetry) and TENSOR (cylindrical symmetry), are used to illustrate the effects of variations in the material properties of various media on the cratering processes, namely shock, spall, and gas acceleration. Water content is found to be the most important material property, followed by strength, porosity, and compressibility. Crater profile calculations are presented for Pre-Gondola Charley (20-ton nitromethane detonation in shale) and Sedan (100-kt nuclear detonation in alluvium). Calculations also are presented for three 1-Mt yields in saturated Divide basalt and 1-Mt yield in dry Buckboard basalt, to show crater geometry as a function of the burial depth for large explosive yields. The calculations show, for megaton-level yields, that gas acceleration is the dominate mechanism in determining crater size and depends in turn on the water content in the medium. (author)

  11. Nuclear cratering on a digital computer

    International Nuclear Information System (INIS)

    Terhune, R.W.; Stubbs, T.F.; Cherry, J.T.

    1970-01-01

    Computer programs based on the artificial viscosity method are applied to developing an understanding of the physics of cratering, with emphasis on cratering by nuclear explosives. Two established codes, SOC (spherical symmetry) and TENSOR (cylindrical symmetry), are used to illustrate the effects of variations in the material properties of various media on the cratering processes, namely shock, spall, and gas acceleration. Water content is found to be the most important material property, followed by strength, porosity, and compressibility. Crater profile calculations are presented for Pre-Gondola Charley (20-ton nitromethane detonation in shale) and Sedan (100-kt nuclear detonation in alluvium). Calculations also are presented for three 1-Mt yields in saturated Divide basalt and 1-Mt yield in dry Buckboard basalt, to show crater geometry as a function of the burial depth for large explosive yields. The calculations show, for megaton-level yields, that gas acceleration is the dominate mechanism in determining crater size and depends in turn on the water content in the medium. (author)

  12. Centrifuge impact cratering experiment 5

    Science.gov (United States)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  13. Cutting Craters

    Science.gov (United States)

    2003-01-01

    [figure removed for brevity, see original site] Released 12 November 2003The rims of two old and degraded impact craters are intersected by a graben in this THEMIS image taken near Mangala Fossa. Yardangs and low-albedo wind streaks are observed at the top of the image as well as interesting small grooves on the crater floor. The origin of these enigmatic grooves may be the result of mud or lava and volatile interactions. Variable surface textures observed in the bottom crater floor are the result of different aged lava flows.Image information: VIS instrument. Latitude -15.2, Longitude 219.2 East (140.8 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Alteration of Basaltic Glass to Mg/Fe-Smectite under Acidic Conditions: A Potential Smectite Formation Mechanism on Mars

    Science.gov (United States)

    Peretyazhko, Tanya; Sutter, Brad; Ming, Douglas W.

    2014-01-01

    Phyllosilicates of the smectite group including Mg- and Fe-saponite and Fe(III)-rich nontronite have been identified on Mars. Smectites are believed to be formed under neutral to alkaline conditions that prevailed on early Mars. This hypothesis is supported by the observation of smectite and carbonate deposits in Noachian terrain on Mars. However, smectite may have formed under mildly acidic conditions. Abundant smectite formations have been detected as layered deposits hundreds of meters thick in intracrater depositional fans and plains sediments, while no large deposits of carbonates are found. Development of mildly acidic conditions at early Mars might allow formation of smectite but inhibit widespread carbonate precipitation. Little is known regarding the mechanisms of smectite formation from basaltic glass under acidic conditions. The objective of this study was to test a hypothesis that Mars-analogue basaltic glass alters to smectite minerals under acidic conditions (pH 4). The effects of Mg and Fe concentrations and temperature on smectite formation from basaltic glass were evaluated. Phyllosilicate synthesis was performed in batch reactors (Parr acid digestion vessel) under reducing hydrothermal conditions at 200 C and 100 C. Synthetic basaltic glass with a composition similar to that of the Gusev crater rock Adirondack (Ground surface APXS measurement) was used in these experiments. Basaltic glass was prepared by melting and quenching procedures. X-ray diffraction (XRD) analysis indicated that the synthesized glass was composed of olivine, magnetite and X-ray amorphous phase. Samples were prepared by mixing 250 mg Adirondack with 0.1 M acetic acid (final pH 4). In order to study influence of Mg concentration on smectite formation, experiments were performed with addition of 0, 1 and 10 mM MgCl2. After 1, 7 and 14 day incubations the solution composition was analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the altered glass and formed

  15. Magnetic Properties Experiments on the Mars exploration Rover Spirit at Gusev crater

    DEFF Research Database (Denmark)

    Bertelsen, Pernille; Goetz, W.; Madsen, M.B.

    2004-01-01

    The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars-and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere...... must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of similar to2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit....

  16. Summary of results of cratering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Toman, J [Lawrence Radiation Laboratory, Livermore, CA (United States)

    1969-07-01

    The use of nuclear excavation as a construction technique for producing harbors, canals, highway cuts, and other large excavations requires a high assurance that the yield and depth of burst selected for the explosive will produce the desired configuration within an acceptable degree of tolerance. Nuclear excavation technology advanced significantly during 1968 as a result of the successful execution of Projects Cabriolet, Buggy, and Schooner. Until these experiments were conducted, the only nuclear data available for designing large excavations were derived from Sedan (100 kt in alluvium), Danny Boy (0.42 kt in basalt), and Sulky (0.090 kt in basalt). Applicable experience has now been extended to include two additional rock types: tuff and porphyritic trachyte, non-homogeneous formations with severe geologic layering, and a nuclear row in hard rock. The continued development of cratering calculations using in situ geophysical measurements and high-pressure test data have provided a means for predicting the cratering characteristics of untested materials. Chemical explosive cratering experiments conducted in the pre-Gondola series during the past several years have been directed toward determining the behavior of weak, wet clay shales. This material is important to nuclear excavation because of potential long-term stability problems which may affect the cratered slopes. (author)

  17. Summary of results of cratering experiments

    International Nuclear Information System (INIS)

    Toman, J.

    1969-01-01

    The use of nuclear excavation as a construction technique for producing harbors, canals, highway cuts, and other large excavations requires a high assurance that the yield and depth of burst selected for the explosive will produce the desired configuration within an acceptable degree of tolerance. Nuclear excavation technology advanced significantly during 1968 as a result of the successful execution of Projects Cabriolet, Buggy, and Schooner. Until these experiments were conducted, the only nuclear data available for designing large excavations were derived from Sedan (100 kt in alluvium), Danny Boy (0.42 kt in basalt), and Sulky (0.090 kt in basalt). Applicable experience has now been extended to include two additional rock types: tuff and porphyritic trachyte, non-homogeneous formations with severe geologic layering, and a nuclear row in hard rock. The continued development of cratering calculations using in situ geophysical measurements and high-pressure test data have provided a means for predicting the cratering characteristics of untested materials. Chemical explosive cratering experiments conducted in the pre-Gondola series during the past several years have been directed toward determining the behavior of weak, wet clay shales. This material is important to nuclear excavation because of potential long-term stability problems which may affect the cratered slopes. (author)

  18. Distribution and stratigraphy of basaltic units in Maria Tranquillitatis and Fecunditatis: A Clementine perspective

    Science.gov (United States)

    Rajmon, D.; Spudis, P.

    2004-01-01

    Maria Tranquillitatis and Fecunditatis have been mapped based on Clementine image mosaics and derived iron and titanium maps. Impact craters served as stratigraphic probes enabling better delineation of compositionally different basaltic units, determining the distribution of subsurface basalts, and providing estimates of total basalt thickness and the thickness of the surface units. Collected data indicate that volcanism in these maria started with the eruption of low-Ti basalts and evolved toward medium- and high-Ti basalts. Some of the high-Ti basalts in Mare Tranquillitatis began erupting early and were contemporaneous with the low- and medium-Ti basalts; these units form the oldest units exposed on the mare surface. Mare Tranquillitatis is mostly covered with high- Ti basalts. In Mare Fecunditatis, the volume of erupting basalts clearly decreased as the Ti content increased, and the high-Ti basalts occur as a few patches on the mare surface. The basalt in both maria is on the order of several hundred meters thick and locally may be as thick as 1600 m. The new basalt thickness estimates generally fall within the range set by earlier studies, although locally differ. The medium- to high-Ti basalts exposed at the surfaces of both maria are meters to tens of meters thick.

  19. Mineralogy of a mudstone at Yellowknife Bay, Gale crater, Mars

    NARCIS (Netherlands)

    Vaniman, D.T.; Bish, D.L.; Ming, D.W.; Bristow, T.F.; Morris, R.V.; Blake, D.F.; Chipera, S.J.; Morrison, S.M.; Treiman, A.H.; Rampe, E.B.; Rice, M.; Achilles, C.N.; Grotzinger, J.P.; McLennan, S.M.; Williams, J.; Bell III, J.F.; Newsom, H.E.; Downs, R.T.; Maurice, S.; Sarrazin, P.; Yen, A.S.; Morookian, J.M.; Farmer, J.D.; Stack, K.; Milliken, R.E.; Ehlmann, B.L.; Sumner, D.Y.; Berger, G.; Crisp, J.A.; Hurowitz, J.A.; Anderson, R.; Des Marais, D.J.; Stolper, E.M.; Edgett, K.S.; Gupta, S.; Spanovich, N.; MSL Science Team, the|info:eu-repo/dai/nl/292012217

    2014-01-01

    Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John

  20. BASALT A: Basaltic Terrains in Idaho and Hawaii as Planetary Analogs for Mars Geology and Astrobiology

    Science.gov (United States)

    Hughes, Scott S.; Haberle, Christopher W.; Nawotniak, Shannon E. Kobs; Sehlke, Alexander; Garry, W. Brent; Elphic, Richard C.; Payler, Sam J.; Stevens, Adam H.; Cockell, Charles S.; Brady, Allyson L.; hide

    2018-01-01

    Assessments of field research target regions are described within two notably basaltic geologic provinces as Earth analogs to Mars. Regions within the eastern Snake River Plain of Idaho and the Big Island of Hawaii, USA, provinces that represent analogs of present-day and early Mars, respectively, were evaluated on the basis of geologic settings, rock lithology and geochemistry, rock alteration, and climate. Each of these factors provide rationale for the selection of specific targets for field research in five analog target regions: (1) Big Craters and (2) Highway lava flows at Craters of the Moon National Monument and Preserve, Idaho; and (3) Mauna Ulu low shield, (4) Kilauea Iki lava lake and (5) Kilauea caldera in the Kilauea Volcano summit region and the East Rift Zone of Hawaii. Our evaluation of compositional and textural differences, as well as the effects of syn- and post-eruptive rock alteration, shows that the basaltic terrains in Idaho and Hawaii provide a way to characterize the geology and major geologic substrates that host biological activity of relevance to Mars exploration. This work provides the foundation to better understand the scientific questions related to the habitability of basaltic terrains, the rationale behind selecting analog field targets, and their applicability as analogs to Mars.

  1. Dome craters on Ganymede

    International Nuclear Information System (INIS)

    Moore, J.M.; Malin, M.C.

    1987-01-01

    Voyager observations reveal impact craters on Ganymede that are characterized by the presence of broad, high albedo, topographic domes situated within a central pit. Fifty-seven craters with central domes were identified in images covering approx. 50% of the surface. Owing to limitations in resolution, and viewing and illumination angles, the features identified are most likely a subset of dome craters. The sample appears to be sufficiently large to infer statistically meaningful trends. Dome craters appear to fall into two distinct populations on plots of the ratio of dome diameter to crater rim diameter, large-dome craters and small-dome craters. The two classes are morphologically distinct from one another. In general, large dome craters show little relief and their constituent landforms appear subdued with respect to fresh craters. The physical attributes of small-dome craters are more sharply defined, a characteristic they share with young impact craters of comparable size observed elsewhere in the solar system. Both types of dome craters exhibit central pits in which the dome is located. As it is difficult to produce domes by impact and/or erosional processes, an endogenic origin for the domes is reasonably inferred. Several hypotheses for their origin are proposed. These hypotheses are briefly reviewed

  2. Degraded Crater Rim

    Science.gov (United States)

    2002-01-01

    (Released 3 May 2002) The Science The eastern rim of this unnamed crater in Southern Arabia Terra is very degraded (beaten up). This indicates that this crater is very ancient and has been subjected to erosion and subsequent bombardment from other impactors such as asteroids and comets. One of these later (younger) craters is seen in the upper right of this image superimposed upon the older crater rim material. Note that this smaller younger crater rim is sharper and more intact than the older crater rim. This region is also mantled with a blanket of dust. This dust mantle causes the underlying topography to take on a more subdued appearance. The Story When you think of Arabia, you probably think of hot deserts and a lot of profitable oil reserves. On Mars, however, Southern Arabia Terra is a cold place of cratered terrain. This almost frothy-looking image is the badly battered edge of an ancient crater, which has suffered both erosion and bombardment from asteroids, comets, or other impacting bodies over the long course of its existence. A blanket of dust has also settled over the region, which gives the otherwise rugged landscape a soft and more subdued appearance. The small, round crater (upper left) seems almost gemlike in its setting against the larger crater ring. But this companionship is no easy romance. Whatever formed the small crater clearly whammed into the larger crater rim at some point, obliterating part of its edge. You can tell the small crater was formed after the first and more devastating impact, because it is laid over the other larger crater. How much younger is the small one? Well, its rim is also much sharper and more intact, which gives a sense that it is probably far more youthful than the very degraded, ancient crater.

  3. Comparisons of Unconsolidated Sediments Analyzed by APXS (MSL-Curiosity) within Gale Crater, Mars: Soils, Sands of the Barchan and Linear Dunes of the Active Bagnold Dune Field, and Ripple-field Sands.

    Science.gov (United States)

    Thompson, L. M.; O'Connell-Cooper, C.; Spray, J. G.; Gellert, R.; Boyd, N. I.; Desouza, E.

    2017-12-01

    The MSL-APXS has analyzed a variety of unconsolidated sediments within the Gale impact crater, including soils, sands from barchan [High, Namib dunes], and linear dunes [Nathan Bridges, Mount Desert dunes], within the active Bagnold dune field, and sands from two smaller ripple fields ("mega-ripples"). The Gale "soils" (unsorted, unconsolidated sediments, ranging from fine-grained particles (including dust) to coarser "pebbly" material [>2 mm]), are, to a large degree, similar to Martian basaltic soils quantified by APXS, at Gusev crater (MER-A_Spirit) and Meridiani Planum (MER-B_Opportunity). Some local contributions are indicated by, for example, the enriched K levels (relative to a martian average basaltic soil [ABS]) within coarser Gale soil samples, and a Cr, Mn, Fe enrichment within finer-grained samples. Sands (grain size 62 µm to 2 mm) of the Bagnold dunes, generally, exhibit elevated Mg and Ni, indicating enrichment from olivine and pyroxene, but depleted S, Cl and Zn, indicating high activity levels and low dust. Compositional differences, related both to position within a dune (i.e., crest versus off-crest sand), and type of dune (linear versus barchan), are identified. Off-crest sands have Na, Al, Si, K, P contents similar to (or slightly depleted, relative to) the ABS, enrichment in Mg, and low dust content, whilst crest sands contain very high Mg and Ni (relative to the ABS), low felsic elemental concentrations and very low dust content. Cr is significantly enriched (and, to a lesser degree, Mn, Fe, Ti) in the off-crest sands of the linear dunes. In contrast, barchan dunes off-crest sands have Cr, Mn, Fe, and Ti abundances similar to those in the Gale soils. Additionally, Ni concentrations in barchan dunes off-crest sands are enriched relative to the linear dunes. Analyses from a small, isolated "mega-ripple" reveal a composition similar to that of the Gale soils, including a high dust content. The second mega-ripple, within a larger ripple field, is

  4. The Thickness and Volume of Young Basalts Within Mare Imbrium

    Science.gov (United States)

    Chen, Yuan; Li, Chunlai; Ren, Xin; Liu, Jianjun; Wu, Yunzhao; Lu, Yu; Cai, Wei; Zhang, Xunyu

    2018-02-01

    Basaltic volcanism is one of the most important geologic processes of the Moon. Research on the thickness and volume of late-stage basalts of Mare Imbrium helps better understand the source of lunar volcanism and eruption styles. Based on whether apparent flow fronts exist or not, the late-stage basalts within Mare Imbrium were divided into two groups, namely, Upper Eratosthenian basalts (UEm) and Lower Eratosthenian basalts (LEm). Employing the topographic profile analysis method for UEm and the crater excavation technique for LEm, we studied the thickness and distribution of Eratosthenian basalts in Mare Imbrium. For the UEm units, their thicknesses were estimated to be 16-34 (±2) m with several layers of individual lava ( 8-13 m) inside. The estimated thickness of LEm units was 14-45(±1) m, with a trend of reducing thickness from north to south. The measured thickness of late-stage basalts around the Chang'E-3 landing site ( 37 ± 1 m) was quite close to the results acquired by the lunar penetrating radar carried on board the Yutu Rover ( 35 m). The total volume of the late-stage basalts in Mare Imbrium was calculated to be 8,671 (±320) km3, which is 4 times lower than that of Schaber's estimation ( 4 × 104 km3). Our results indicate that the actual volume is much lower than previous estimates of the final stage of the late basaltic eruption of Mare Imbrium. Together, the area flux and transport distance of the lava flows gradually decreased with time. These results suggest that late-stage volcanic evolution of the Moon might be revised.

  5. Nevada Test Site craters used for astronaut training

    Science.gov (United States)

    Moore, H. J.

    1977-01-01

    Craters produced by chemical and nuclear explosives at the Nevada Test Site were used to train astronauts before their lunar missions. The craters have characteristics suitable for reconnaissance-type field investigations. The Schooner test produced a crater about 300 m across and excavated more than 72 m of stratigraphic section deposited in a fairly regular fashion so that systematic observations yield systematic results. Other features common on the moon, such as secondary craters and glass-coated rocks, are present at Schooner crater. Smaller explosive tests on Buckboard Mesa excavated rocks from three horizontal alteration zones within basalt flows so that the original sequence of the zones could be determined. One crater illustrated the characteristics of craters formed across vertical boundaries between rock units. Although the exercises at the Nevada Test Site were only a small part of the training of the astronauts, voice transcripts of Apollo missions 14, 16, and 17 show that the exercises contributed to astronaut performance on the moon.

  6. Experimental impact crater morphology

    Science.gov (United States)

    Dufresne, A.; Poelchau, M. H.; Hoerth, T.; Schaefer, F.; Thoma, K.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The research group MEMIN (Multidisciplinary Experimental and Impact Modelling Research Network) is conducting impact experiments into porous sandstones, examining, among other parameters, the influence of target pore-space saturation with water, and projectile velocity, density and mass, on the cratering process. The high-velocity (2.5-7.8 km/s) impact experiments were carried out at the two-stage light-gas gun facilities of the Fraunhofer Institute EMI (Germany) using steel, iron meteorite (Campo del Cielo IAB), and aluminium projectiles with Seeberg Sandstone as targets. The primary objectives of this study within MEMIN are to provide detailed morphometric data of the experimental craters, and to identify trends and characteristics specific to a given impact parameter. Generally, all craters, regardless of impact conditions, have an inner depression within a highly fragile, white-coloured centre, an outer spallation (i.e. tensile failure) zone, and areas of arrested spallation (i.e. spall fragments that were not completely dislodged from the target) at the crater rim. Within this general morphological framework, distinct trends and differences in crater dimensions and morphological characteristics are identified. With increasing impact velocity, the volume of craters in dry targets increases by a factor of ~4 when doubling velocity. At identical impact conditions (steel projectiles, ~5km/s), craters in dry and wet sandstone targets differ significantly in that "wet" craters are up to 76% larger in volume, have depth-diameter ratios generally below 0.19 (whereas dry craters are almost consistently above this value) at significantly larger diameters, and their spallation zone morphologies show very different characteristics. In dry craters, the spall zone surfaces dip evenly at 10-20° towards the crater centre. In wet craters, on the other hand, they consist of slightly convex slopes of 10-35° adjacent to the inner depression, and of sub-horizontal tensile

  7. Additive Construction using Basalt Regolith Fines

    Science.gov (United States)

    Mueller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Lippitt, Thomas C.; Mantovani, James G.; Nugent, Matthew W.; Townsend, Ivan I.

    2014-01-01

    Planetary surfaces are often covered in regolith (crushed rock), whose geologic origin is largely basalt. The lunar surface is made of small-particulate regolith and areas of boulders located in the vicinity of craters. Regolith composition also varies with location, reflecting the local bedrock geology and the nature and efficiency of the micrometeorite-impact processes. In the lowland mare areas (suitable for habitation), the regolith is composed of small granules (20 - 100 microns average size) of mare basalt and volcanic glass. Impacting micrometeorites may cause local melting, and the formation of larger glassy particles, and this regolith may contain 10-80% glass. Studies of lunar regolith are traditionally conducted with lunar regolith simulant (reconstructed soil with compositions patterned after the lunar samples returned by Apollo). The NASA Kennedy Space Center (KSC) Granular Mechanics & Regolith Operations (GMRO) lab has identified a low fidelity but economical geo-technical simulant designated as Black Point-1 (BP-1). It was found at the site of the Arizona Desert Research and Technology Studies (RATS) analog field test site at the Black Point lava flow in adjacent basalt quarry spoil mounds. This paper summarizes activities at KSC regarding the utilization of BP-1 basalt regolith and comparative work with lunar basalt simulant JSC-1A as a building material for robotic additive construction of large structures. In an effort to reduce the import or in-situ fabrication of binder additives, we focused this work on in-situ processing of regolith for construction in a single-step process after its excavation. High-temperature melting of regolith involves techniques used in glassmaking and casting (with melts of lower density and higher viscosity than those of metals), producing basaltic glass with high durability and low abrasive wear. Most Lunar simulants melt at temperatures above 1100 C, although melt processing of terrestrial regolith at 1500 C is not

  8. Centrifuge Impact Cratering Experiments

    Science.gov (United States)

    Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.

    1985-01-01

    The kinematics of crater growth, impact induced target flow fields and the generation of impact melt were determined. The feasibility of using scaling relationships for impact melt and crater dimensions to determine impactor size and velocity was studied. It is concluded that a coupling parameter determines both the quantity of melt and the crater dimensions for impact velocities greater than 10km/s. As a result impactor radius, a, or velocity, U cannot be determined individually, but only as a product in the form of a coupling parameter, delta U micron. The melt volume and crater volume scaling relations were applied to Brent crater. The transport of melt and the validity of the melt volume scaling relations are examined.

  9. Buried Craters of Utopia

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-365, 19 May 2003Beneath the northern plains of Mars are numerous buried meteor impact craters. One of the most heavily-cratered areas, although buried, occurs in Utopia Planitia, as shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. The history of Mars is complex; impact craters provide a tool by which to understand some of that history. In this case, a very ancient, cratered surface was thinly-buried by younger material that is not cratered at all. This area is near 48.1oN, 228.2oW; less than 180 km (112 mi) west of the Viking 2 lander site. Sunlight illuminates the scene from the lower left.

  10. High Resolution Digital Elevation Models of Pristine Explosion Craters

    Science.gov (United States)

    Farr, T. G.; Krabill, W.; Garvin, J. B.

    2004-01-01

    In order to effectively capture a realistic terrain applicable to studies of cratering processes and landing hazards on Mars, we have obtained high resolution digital elevation models of several pristine explosion craters at the Nevada Test Site. We used the Airborne Terrain Mapper (ATM), operated by NASA's Wallops Flight Facility to obtain DEMs with 1 m spacing and 10 cm vertical errors of 4 main craters and many other craters and collapse pits. The main craters that were mapped are Sedan, Scooter, Schooner, and Danny Boy. The 370 m diameter Sedan crater, located on Yucca Flat, is the largest and freshest explosion crater on Earth that was formed under conditions similar to hypervelocity impact cratering. As such, it is effectively pristine, having been formed in 1962 as a result of a controlled detonation of a 100 kiloton thermonuclear device, buried at the appropriate equivalent depth of burst required to make a simple crater. Sedan was formed in alluvium of mixed lithology and subsequently studied using a variety of field-based methods. Nearby secondary craters were also formed at the time and were also mapped by ATM. Adjacent to Sedan and also in alluvium is Scooter, about 90 m in diameter and formed by a high-explosive event. Schooner (240 m) and Danny Boy (80 m) craters were also important targets for ATM as they were excavated in hard basalt and therefore have much rougher ejecta. This will allow study of ejecta patterns in hard rock as well as engineering tests of crater and rock avoidance and rover trafficability. In addition to the high resolution DEMs, crater geometric characteristics, RMS roughness maps, and other higher-order derived data products will be generated using these data. These will provide constraints for models of landing hazards on Mars and for rover trafficability. Other planned studies will include ejecta size-frequency distribution at the resolution of the DEM and at finer resolution through air photography and field measurements

  11. Basalt stratigraphy - Pasco Basin

    International Nuclear Information System (INIS)

    Waters, A.C.; Myers, C.W.; Brown, D.J.; Ledgerwood, R.K.

    1979-10-01

    The geologic history of the Pasco Basin is sketched. Study of the stratigraphy of the area involved a number of techniques including major-element chemistry, paleomagnetic investigations, borehole logging, and other geophysical survey methods. Grande Ronde basalt accumulation in the Pasco Basin is described. An illustrative log response is shown. 1 figure

  12. Crater in Utopia

    Science.gov (United States)

    2004-01-01

    23 March 2004 Craters of the martian northern plains tend to be somewhat shallow because material has filled them in. Their ejecta blankets, too, are often covered by younger materials. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example--a crater in Utopia Planitia near 43.7oN, 227.3oW. Erosion has roughened some of the surfaces of the material that filled the crater and covered its ejecta deposit. The picture covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  13. Polygons on Crater Floor

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-357, 11 May 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a pattern of polygons on the floor of a northern plains impact crater. These landforms are common on crater floors at high latitudes on Mars. Similar polygons occur in the arctic and antarctic regions of Earth, where they indicate the presence and freeze-thaw cycling of ground ice. Whether the polygons on Mars also indicate water ice in the ground is uncertain. The image is located in a crater at 64.8oN, 292.7oW. Sunlight illuminates the scene from the lower left.

  14. Remote Sensing Observations and Numerical Simulation for Martian Layered Ejecta Craters

    Science.gov (United States)

    Li, L.; Yue, Z.; Zhang, C.; Li, D.

    2018-04-01

    To understand past Martian climates, it is important to know the distribution and nature of water ice on Mars. Impact craters are widely used ubiquitous indicators for the presence of subsurface water or ice on Mars. Remote sensing observations and numerical simulation are powerful tools for investigating morphological and topographic features on planetary surfaces, and we can use the morphology of layered ejecta craters and hydrocode modeling to constrain possible layering and impact environments. The approach of this work consists of three stages. Firstly, the morphological characteristics of the Martian layered ejecta craters are performed based on Martian images and DEM data. Secondly, numerical modeling layered ejecta are performed through the hydrocode iSALE (impact-SALE). We present hydrocode modeling of impacts onto targets with a single icy layer within an otherwise uniform basalt crust to quantify the effects of subsurface H2O on observable layered ejecta morphologies. The model setup is based on a layered target made up of a regolithic layer (described by the basalt ANEOS), on top an ice layer (described by ANEOS equation of H2O ice), in turn on top of an underlying basaltic crust. The bolide is a 0.8 km diameter basaltic asteroid hitting the Martian surface vertically at a velocity of 12.8 km/s. Finally, the numerical results are compared with the MOLA DEM profile in order to analyze the formation mechanism of Martian layered ejecta craters. Our simulations suggest that the presence of an icy layer significantly modifies the cratering mechanics, and many of the unusual features of SLE craters may be explained by the presence of icy layers. Impact cratering on icy satellites is significantly affected by the presence of subsurface H2O.

  15. Mercury's Densely Cratered Surface

    Science.gov (United States)

    1974-01-01

    Mariner 10 took this picture (FDS 27465) of the densely cratered surface of Mercury when the spacecraft was 18,200 kilometers (8085 miles) from the planet on March 29. The dark line across top of picture is a 'dropout' of a few TV lines of data. At lower left, a portion of a 61 kilometer (38 mile) crater shows a flow front extending across the crater floor and filling more than half of the crater. The smaller, fresh crater at center is about 25 kilometers (15 miles) in diameter. Craters as small as one kilometer (about one-half mile) across are visible in the picture.The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.Image Credit: NASA/JPL/Northwestern University

  16. Multivariate analyses of crater parameters and the classification of craters

    Science.gov (United States)

    Siegal, B. S.; Griffiths, J. C.

    1974-01-01

    Multivariate analyses were performed on certain linear dimensions of six genetic types of craters. A total of 320 craters, consisting of laboratory fluidization craters, craters formed by chemical and nuclear explosives, terrestrial maars and other volcanic craters, and terrestrial meteorite impact craters, authenticated and probable, were analyzed in the first data set in terms of their mean rim crest diameter, mean interior relief, rim height, and mean exterior rim width. The second data set contained an additional 91 terrestrial craters of which 19 were of experimental percussive impact and 28 of volcanic collapse origin, and which was analyzed in terms of mean rim crest diameter, mean interior relief, and rim height. Principal component analyses were performed on the six genetic types of craters. Ninety per cent of the variation in the variables can be accounted for by two components. Ninety-nine per cent of the variation in the craters formed by chemical and nuclear explosives is explained by the first component alone.

  17. Geology of drill hole USW VH-2, and structure of Crater Flat, southwestern Nevada

    International Nuclear Information System (INIS)

    Carr, W.J.; Parrish, L.D.

    1985-01-01

    A 1219 meter (4000 ft) drill hole in Crater Flat shows the absence of buried Pliocene or Quaternary volcanic rocks, and penetrates a section of Timber Mountain, Paintbrush, and the upper part of the Crater Flat Tuffs, similar to that exposed adjacent to Crater Flat. A prominent negative aeromagnetic anomaly between the drill hole and Bare Mountain is attributed to a westward thickening section of a reversely magnetized Miocene basalt. The relatively shallow depth of this basalt in the west-central part of Crater Flat indicates that no large amount of tectonic movement has occurred in approximately the last 10 m.y. Massive brecciated wedges of Paleozoic rocks are penetrated in two stratigraphic intervals in the drill hole; the older one, between the Tiva Canyon Member of the Paintbrush Tuff and the Rainier Mesa Member of the Timber Mountain Tuff, correlates with the time of maximum faulting east of Crater Flat in the Yucca Mountain area. The younger slide masses are correlated with a large slide block of probable late Miocene age exposed along the southwestern rim of Crater Flat. The structural pattern and style buried beneath central and western Crater Flat is deduced to be similar to that exposed at Yucca Mountain, but less developed. The major fault system controlling the steep east face of Bare Mountain, though probably still active, is believed to have developed mainly as a result of caldera collapse between 13 and 14 m.y. ago. Relations between faulting and four episodes of basalt eruption in the Crater Flat area strongly suggest contemporaneity of the two processes. 17 refs., 2 figs., 3 tabs

  18. Craters on comets

    Science.gov (United States)

    Vincent, J.; Oklay, N.; Marchi, S.; Höfner, S.; Sierks, H.

    2014-07-01

    This paper reviews the observations of crater-like features on cometary nuclei. ''Pits'' have been observed on almost all cometary nuclei but their origin is not fully understood [1,2,3,4]. It is currently assumed that they are created mainly by the cometary activity with a pocket of volatiles erupting under a dust crust, leaving a hole behind. There are, however, other features which cannot be explained in this way and are interpreted alternatively as remnants of impact craters. This work focusses on the second type of pit features: impact craters. We present an in-depth review of what has been observed previously and conclude that two main types of crater morphologies can be observed: ''pit-halo'' and ''sharp pit''. We extend this review by a series of analysis of impact craters on cometary nuclei through different approaches [5]: (1) Probability of impact: We discuss the chances that a Jupiter Family Comet like 9P/Tempel 1 or the target of Rosetta 67P/Churyumov-Gerasimenko can experience an impact, taking into account the most recent work on the size distribution of small objects in the asteroid Main Belt [6]. (2) Crater morphology from scaling laws: We present the status of scaling laws for impact craters on cometary nuclei [7] and discuss their strengths and limitations when modeling what happens when a rocky projectile hits a very porous material. (3) Numerical experiments: We extend the work on scaling laws by a series of hydrocode impact simulations, using the iSALE shock physics code [8,9,10] for varying surface porosity and impactor velocity (see Figure). (4) Surface processes and evolution: We discuss finally the fate of the projectile and the effects of the impact-induced surface compaction on the activity of the nucleus. To summarize, we find that comets do undergo impacts although the rapid evolution of the surface erases most of the features and make craters difficult to detect. In the case of a collision between a rocky body and a highly porous

  19. Characterization and Distribution of Lunar Mare Basalt Types Using Remote Sensing Techniques. Ph.D. Thesis

    Science.gov (United States)

    Pieters, C.

    1977-01-01

    The types of basal to be found on the moon were identified using reflectance spectra from a variety of lunar mare surfaces and craters as well as geochemical interpretations of laboratory measurements of reflectance from lunar, terrestrial, and meteoritic samples. Findings indicate that major basaltic units are not represented in lunar sample collections. The existence of late stage high titanium basalts is confirmed. All maria contain lateral variations of compositionally heterogenous basalts; some are vertically inhomogenous with distinctly different subsurface composition. Some basalt types are spectrally gradational, suggesting minor variations in composition. Mineral components of unsampled units can be defined if spectra are obtained with sufficient spectral coverage (.3 to 2.5 micron m) and spatial resolution (approximating .5 km).

  20. Diversity of basaltic lunar volcanism associated with buried impact structures: Implications for intrusive and extrusive events

    Science.gov (United States)

    Zhang, F.; Zhu, M.-H.; Bugiolacchi, R.; Huang, Q.; Osinski, G. R.; Xiao, L.; Zou, Y. L.

    2018-06-01

    Relatively denser basalt infilling and the upward displacement of the crust-mantle interface are thought to be contributing factors for the quasi-circular mass anomalies for buried impact craters in the lunar maria. Imagery and gravity observations from the Lunar Reconnaissance Orbiter (LRO) and dual Gravity Recovery and Interior Laboratory (GRAIL) missions have identified 10 partially or fully buried impact structures where diversity of observable basaltic mare volcanism exists. With a detailed investigation of the characteristics of associated volcanic landforms, we describe their spatial distribution relationship with respect to the subsurface tectonic structure of complex impact craters and propose possible models for the igneous processes which may take advantage of crater-related zones of weakness and enable magmas to reach the surface. We conclude that the lunar crust, having been fractured and reworked extensively by cratering, facilitates substance and energy exchange between different lunar systems, an effect modulated by tectonic activities both at global and regional scales. In addition, we propose that the intrusion-caused contribution to gravity anomalies should be considered in future studies, although this is commonly obscured by other physical factors such as mantle uplift and basalt load.

  1. Characteristics Of Basaltic Sand: Size, Shape, And Composition As A Function Of Transport Process And Distance

    Science.gov (United States)

    Craddock, R. A.; Needell, Z. A.; Rose, T. R.

    2012-04-01

    Overview: The chemical and physical characteristics of sedimentary material can provide valuable clues about transport processes, distance traveled, and provenance, all of which are aspects of Martian geography that we would like to better understand. For a typical sedimentary deposit on Earth, for example, it has been shown that the ratio of feldspar to quartz can be used to assess the maturity (or transport distance) of a terrestrial deposit, because feldspar is more vulnerable to weathering than quartz. Further, chemical analysis can also be used to determine potential sediment sources, and grain-size sorting can be used to distinguish aeolian sediments (typically well-sorted) from fluvial sediments (poorly sorted in high energy environments). It is also common to use the shapes of individual quartz particles to determine transport process and distance, all of which can help us better understand the history of a sample of sedimentary material and the geological processes that created and emplaced it. These traditional sedimentological concepts are now being applied to our interpretation of Martian surface materials. Sullivan et al. [2008], for example, used grain-size and shape to assess eolian processes and to qualify transport distances of deposits found at the Spirit landing site in Gusev Crater. Stockstill-Cahill et al. [62008 used variations in mineral abundances observed in multispectral data to determine the provenance of dark dunes found in Amazonis Planitia craters. While applying our understanding of terrestrial sedimentary materials to Martian surface materials is intuitively sound and logical, the problem is that most of our current understanding is based on sediments derived from felsic materials (e.g., granite) primarily because that is the composition of most of the landmass on the Earth. However, the Martian surface is composed primarily of mafic material, or basalt, which generates much different sedimentary particles as it weathers. Instead of

  2. Pyroclastic Deposits in the Floor-fractured Crater Alphonsus

    Science.gov (United States)

    Allen, Carlton C.; Donaldson-Hanna, Kerri L.; Pieters, Carle M.; Moriarty, Daniel P.; Greenhagen, Benjamin T.; Bennett, Kristen A.; Kramer, Georgiana Y.; Paige, David A.

    2013-01-01

    Alphonsus, the 118 km diameter floor-fractured crater, is located immediately east of Mare Nubium. Eleven pyroclastic deposits have been identified on the crater's floor. Early telescopic spectra suggest that the floor of Alphonsus is noritic, and that the pyroclastic deposits contain mixtures of floor material and a juvenile component including basaltic glass. Head and Wilson contend that Nubium lavas intruded the breccia zone beneath Alphonsus, forming dikes and fractures on the crater floor. In this model, the magma ascended to the level of the mare but cooled underground, and a portion broke thru to the surface in vulcanian (explosive) eruptions. Alternatively, the erupted material could be from a source unrelated to the mare, in the style of regional pyroclastic deposits. High-resolution images and spectroscopy from the Moon Mineralogy Mapper (M3), Diviner Lunar Radiometer, and Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (NAC) provide data to test these formation models. Spectra from M3 confirm that the crater floor is primarily composed of noritic material, and that the Nubium lavas are basaltic. Spectra from the three largest pyroclastic deposits in Alphonsus are consistent with a minor low- Ca pyroxene component in a glass-rich matrix. The centers of the 2 micron absorption bands have wavelengths too short to be of the same origin as the Nubium basalts. Diviner Christiansen feature (CF) values were used to estimate FeO abundances for the crater floor, Nubium soil, and pyroclastic deposits. The estimated abundance for the crater floor (7.5 +/- 1.4 wt.%) is within the range of FeO values for Apollo norite samples. However, the estimated FeO abundance for Nubium soil (13.4 +/- 1.4 wt.%) is lower than those measured in most mare samples. The difference may reflect contamination of the mare soil by highland ejecta. The Diviner-derived FeO abundance for the western pyroclastic deposit is 13.8 +/- 3.3 wt.%. This is lower than the values for mare soil

  3. Thirteen Iron Meteorites Found at Gale Crater, Meridiani Planum, and Gusev Crater — Exogenic Witnesses to Weathering Processes Near the Martian Equator

    Science.gov (United States)

    Ashley, J.

    2014-12-01

    At least 20 meteorites and meteorite candidates have now been found by science teams at three Mars rover landing sites, all within 15 degrees of the martian equator. Thirteen of these are iron meteorites, comprising 65% of the population — an order of magnitude greater abundance than found among witnessed iron falls in Earth-based collections (~6%). Chondritic meteorites, which comprise some 86% of Earth-based falls, are conspicuously absent from the Mars inventory. The reasons for this disproportion may involve a) post-fall environmental resistance differences favoring iron survivability; b) fragmentation from impact shock (and possibly internal weathering stresses associated with oxide production in desert environments [1]); combined with c) selection biases arising from residual chondritic fragments appearing less conspicuous. Impact features along rover traverses often show evidence of dark materials likely to be impactor fragments [e.g., 2], which could represent the missing chondritic fraction. The reactivity of reduced (metallic) iron to aqueous alteration, combined with the near equatorial and widely distributed locations of these rocks, makes them particularly useful to the assessment of climate models arguing for geologically recent ice at the martian equator. Exposure histories involving alternating wind/water cycles are imprinted on several Meridiani irons, for example [3]. Evidence for oxide coating removal demonstrates the current epoch to be one of coating destruction, not production, showing that atmospheric exposure alone is insufficient to produce the coating. Cavernous weathering is likely associated with acidic corrosion, while evidence of aeolian scouring is found in Widmanstätten patterns, sharp-crested scallops, regmaglypt enlargement, and abundant pitting. Further study of these features could help constrain wind direction and velocity during epochs of sculpting [e.g., 4], and assist in exposure age estimation. References: [1] Ashley J. W. and M. A. Velbel (2000), MAPS, v. 35 no. 5 Supplement, p. A22. [2] Golombek et al., (2010) J. Geophys. Res., 115, E00F08, doi:10.1029/2010JE003628. [3] Ashley J. W. et al., (2011) J. Geophys. Res., 116, E00F20, doi:10.1029/2010JE003672. [4] Greeley R. et al., (2002) J. Geophys. Res., 107, E1, 5005, doi : 10.1029/2000JE001481.

  4. Mineralogy of a Mudstone at Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    Vaniman, D. T.; Bish, D. L.; Ming, D. W.; Bristow, T. F.; Morris, R. V.; Blake, D. F.; Chipera, S. J.; Morrison, S. M.; Treiman, A. H.; Rampe, E. B.; Rice, M.; Achilles, C. N.; Grotzinger, J. P.; McLennan, S. M.; Williams, J.; Bell, J. F.; Newsom, H. E.; Downs, R. T.; Maurice, S.; Sarrazin, P.; Yen, A. S.; Morookian, J. M.; Farmer, J. D.; Stack, K.; Milliken, R. E.; Ehlmann, B. L.; Sumner, D. Y.; Berger, G.; Crisp, J. A.; Hurowitz, J. A.; Anderson, R.; Des Marais, D. J.; Stolper, E. M.; Edgett, K. S.; Gupta, S.; Spanovich, N.; Agard, Christophe; Alves Verdasca, José Alexandre; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Atreya, Sushil; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Jeff; Berman, Daniel; Blanco Avalos, Juan J.; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John “Iain”; Cantor, Bruce; Caplinger, Michael; Caride Rodríguez, Javier; Carmosino, Marco; Carrasco Blázquez, Isaías; Charpentier, Antoine; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie “Kenzie”; de la Torre Juarez, Manuel; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; Dietrich, William; Dingler, Robert; Donny, Christophe; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M. Darby; Edgar, Lauren; Edwards, Christopher; Edwards, Laurence; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Flesch, Greg; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; François, Pascaline; Franz, Heather; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez Gómez, Felipe; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Guillemot, Philippe; Guo, Jingnan; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Jones, John; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Malvitte, Alain Lepinette; Leshin, Laurie; Léveillé, Richard; Lewin-Carpintier, Éric; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Mahaffy, Paul; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gérard; Manning, Heidi; Marchand, Geneviève; Marín Jiménez, Mercedes; Martín García, César; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Mauchien, Patrick; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McNair, Sean; Melikechi, Noureddine; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Molina Jurado, Antonio; Moores, John; Mora-Sotomayor, Luis; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Muñoz Caro, Guillermo; Nachon, Marion; Navarro López, Sara; Navarro-González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Nikiforov, Sergey; Niles, Paul; Nixon, Brian; Noe Dobrea, Eldar; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; Owen, Tobias; de Pablo Hernández, Miguel Ángel; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Pepin, Robert; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Richardson, Mark; Robert, François; Robertson, Kevin; Rodriguez Manfredi, José Antonio; Romeral-Planelló, Julio J.; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Sans Fuentes, Sara Alejandra; Saper, Lee; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel “Dan”; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne; Sebastian Martinez, Eduardo; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sobrón Sánchez, Pablo; Spray, John; Squyres, Steven; Stalport, Fabien; Steele, Andrew; Stein, Thomas; Stern, Jennifer; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Sucharski, Bob; Sullivan, Rob; Summons, Roger; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Torres Redondo, Josefina; Trainer, Melissa; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Webster, Chris; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Rebecca; Williams, Richard B. “Mouser”; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Zorzano Mier, María-Paz

    2014-01-01

    Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.

  5. Mineralogy of a mudstone at Yellowknife Bay, Gale crater, Mars.

    Science.gov (United States)

    Vaniman, D T; Bish, D L; Ming, D W; Bristow, T F; Morris, R V; Blake, D F; Chipera, S J; Morrison, S M; Treiman, A H; Rampe, E B; Rice, M; Achilles, C N; Grotzinger, J P; McLennan, S M; Williams, J; Bell, J F; Newsom, H E; Downs, R T; Maurice, S; Sarrazin, P; Yen, A S; Morookian, J M; Farmer, J D; Stack, K; Milliken, R E; Ehlmann, B L; Sumner, D Y; Berger, G; Crisp, J A; Hurowitz, J A; Anderson, R; Des Marais, D J; Stolper, E M; Edgett, K S; Gupta, S; Spanovich, N

    2014-01-24

    Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.

  6. Moessbauer Studies of Volhynian Basalts

    International Nuclear Information System (INIS)

    Bakun-Czubarow, N.; Milczarski, J.; Galazka-Friedman, J.; Szlachta, K.; Forder, S.

    2011-01-01

    The Volhynian basalts studied belong to the effusive-tuffogenic Volhynian Series (Slawatycze Series in Poland), being the large Ediacaran continental igneous province, that covers an area of 200 000 km 2 in the western margin of East European Craton. The series is underlain by the Cryogenian terrigenous Polesie Series with doleritic sills and dikes. The Volhynian Series consists of the rock beds belonging to the three volcanic cycles with different ratios of flood basalts to pyroclastics. The aim of the study was recognition of primary and secondary Fe-bearing minerals, particularly Fe- and Fe-Ti oxides as well as determination of iron oxidation state, that is an important tool in the search for native copper deposits in these rocks. For Moessbauer studies the following rock samples were chosen: the Polesie Series dolerites, the Volhynian Series basalts from the Ukrainian quarries and drill-holes, e.g. from the Volodymir Volhynskaya drilling hole; the Slawatycze Series basalts from Kaplonosy drill-hole in Poland. In the Kaplonosy basalts the content of magnetite decreases with depth, which may be caused by magma differentiation due to fractional crystallization, when Mg content decreases as Ti and Fe - increases in basic magma. In the Kaplonosy basalts the Fe 2+ /Fe 3+ ratio increases with depth, which points to the increase of iron oxidation with the progress of basaltic magma differentiation. (authors)

  7. Geological Structures in the WaIls of Vestan Craters

    Science.gov (United States)

    Mittlefehldt, David; Nathues, A.; Beck, A. W.; Hoffmann, M.; Schaefer, M.; Williams, D. A.

    2014-01-01

    A compelling case can be made that Vesta is the parent asteroid for the howardite, eucrite and diogenite (HED) meteorites [1], although this interpretation has been questioned [2]. Generalized models for the structure of the crust of Vesta have been developed based on petrologic studies of basaltic eucrites, cumulate eucrites and diogenites. These models use inferred cooling rates for different types of HEDs and compositional variations within the clan to posit that the lower crust is dominantly diogenitic in character, cumulate eucrites occur deep in the upper crust, and basaltic eucrites dominate the higher levels of the upper crust [3-5]. These models lack fine-scale resolution and thus do not allow for detailed predictions of crustal structure. Geophysical models predict dike and sill intrusions ought to be present, but their widths may be quite small [6]. The northern hemisphere of Vesta is heavily cratered, and the southern hemisphere is dominated by two 400-500 km diameter basins that excavated deep into the crust [7-8]. Physical modeling of regolith formation on 300 km diameter asteroids predicts that debris layers would reach a few km in thickness, while on asteroids of Vesta's diameter regolith thicknesses would be less [9]. This agrees well with the estimated =1 km thickness of local debris excavated by a 45 km diameter vestan crater [10]. Large craters and basins may have punched through the regolith/megaregolith and exposed primary vestan crustal structures. We will use Dawn Framing Camera (FC) [11] images and color ratio maps from the High Altitude and Low Altitude Mapping Orbits (HAMO, 65 m/pixel; LAMO, 20 m/pixel) to evaluate structures exposed on the walls of craters: two examples are discussed here.

  8. Magnetic Anisotropic Susceptibility Studies on Impact Structures in the Serra Geral Basalt, Paraná Basin, Brazil

    Science.gov (United States)

    Crosta, A. P.; MacDonald, W. D.

    2009-12-01

    Studies of magnetic properties of shocked basalt are underway for two impact craters in the 132 Ma Serra Geral basalt of southern Brazil: the Vista Alegre crater (25.95°S, 41.69°W) in the state of Paraná, with a diameter of 12.4 km, and the Vargeão crater (26.81°S, 52.17°W) in Santa Catarina, of 9.5 km. Shatter cones and quartz planar deformation features (pdfs) have been found at both structures. Uplifted crater rims and external ejecta deposits have been removed by erosion at both craters. The interior of the Vista Alegre crater contains ejecta fallback deposits, typically reworked and weathered, and basalts of the crater floor are poorly exposed. In contrast, shocked basalts are exposed across the interior of the Vargeão structure, ejecta fallback deposits have been removed by erosion, and a central domal uplift of quartzose strata from beneath the basalt is found. Discounting the possibility of differential erosion rates, these differences might suggest that the Vargeão is the older of the two structures. Laboratory experiments elsewhere have suggested that major axes of the ellipse of anisotropic susceptibility (K1 major; K3 minor) could be aligned with the direction of propagation of the shockwave accompanying impact processes. Insufficient exposures exist at Vista Alegre to test this hypothesis. Oriented samples along a NNW-trending diametral profile across the better exposed Vargeão structure did not show a radial alignment of either K1 or K3 relative to the centre of that structure. In general, the mean susceptibility at Vargeão is lower towards the center; the degree of anisotropy is low (Pjcentral uplift. The shape factor (T) varies considerably (-0.5 (prolate) to +0.7 (oblate)); most magnetofabrics are oblate. Only 3 of 16 sites are prolate, and those are near the crater margin. K3 (minimum) axes are mainly steep, with a mean direction steep and slightly north of the center. K1 (maximum) axes are mainly gently plunging (tendency to preferring

  9. Crater Highlands, Tanzania

    Science.gov (United States)

    2006-01-01

    The Shuttle Radar Topography Mission (SRTM), flown aboard Space Shuttle Endeavour in February 2000, acquired elevation measurements for nearly all of Earth's landmass between 60oN and 56oS latitudes. For many areas of the world SRTM data provide the first detailed three-dimensional observation of landforms at regional scales. SRTM data were used to generate this view of the Crater Highlands along the East African Rift in Tanzania. Landforms are depicted with colored height and shaded relief, using a vertical exaggeration of 2X and a southwestwardly look direction. Lake Eyasi is depicted in blue at the top of the image, and a smaller lake occurs in Ngorongoro Crater. Near the image center, elevations peak at 3648 meters (11,968 feet) at Mount Loolmalasin, which is south of Ela Naibori Crater. Kitumbeine (left) and Gelai (right) are the two broad mountains rising from the rift lowlands. Mount Longido is seen in the lower left, and the Meto Hills are in the right foreground. Tectonics, volcanism, landslides, erosion and deposition -- and their interactions -- are all very evident in this view. The East African Rift is a zone of spreading between the African (on the west) and Somali (on the east) crustal plates. Two branches of the rift intersect here in Tanzania, resulting in distinctive and prominent landforms. One branch trends nearly parallel the view and includes Lake Eyasi and the very wide Ngorongoro Crater. The other branch is well defined by the lowlands that trend left-right across the image (below center, in green). Volcanoes are often associated with spreading zones where magma, rising to fill the gaps, reaches the surface and builds cones. Craters form if a volcano explodes or collapses. Later spreading can fracture the volcanoes, which is especially evident on Kitumbeine and Gelai Mountains (left and right, respectively, lower center). The Crater Highlands rise far above the adjacent savannas, capture moisture from passing air masses, and host rain

  10. Polygons and Craters

    Science.gov (United States)

    2005-01-01

    3 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygons enhanced by subliming seasonal frost in the martian south polar region. Polygons similar to these occur in frozen ground at high latitudes on Earth, suggesting that perhaps their presence on Mars is also a sign that there is or once was ice in the shallow subsurface. The circular features are degraded meteor impact craters. Location near: 72.2oS, 310.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  11. Gully formation in terrestrial simple craters: Meteor Crater, USA and Lonar Crater, India

    Science.gov (United States)

    Kumar, P.; Head, J. W.; Kring, D. A.

    2007-12-01

    Geomorphic features such as gullies, valley networks, and channels on Mars have been used as a proxy to understand the climate and landscape evolution of Mars. Terrestrial analogues provide significant insight as to how the various exogenic and endogenic processes might contribute to the evolution of these martian landscapes. We describe here a terrestrial example from Meteor Crater, which shows a spectacular development of gullies throughout the inner wall in response to rainwater precipitation, snow melting and groundwater discharge. As liquid water has been envisaged as one of the important agents of landscape sculpturing, Meteor Crater remains a useful landmark, where planetary geologists can learn some lessons. We also show here how the lithology and structural framework of this crater controls the gully distribution. Like many martian impact craters, it was emplaced in layered sedimentary rocks with an exceptionally well-developed centripetal drainage pattern consisting of individual alcoves, channels and fans. Some of the gullies originate from the rim crest and others from the middle crater wall, where a lithologic transition occurs. Deeply incised alcoves are well-developed on the soft sandstones of the Coconino Formation exposed on the middle crater wall, beneath overlying dolomite. In general, the gully locations are along crater wall radial fractures and faults, which are favorable locales of groundwater flow and discharge; these structural discontinuities are also the locales where the surface runoff from rain precipitation and snow melting can preferentially flow, causing degradation. Like martian craters, channels are well developed on the talus deposits and alluvial fans on the periphery of the crater floor. In addition, lake sediments on the crater floor provide significant evidence of a past pluvial climate, when groundwater seeped from springs on the crater wall. Caves exposed on the lower crater level may point to percolation of surface runoff

  12. Meteor Crater, AZ

    Science.gov (United States)

    2002-01-01

    The Barringer Meteorite Crater (also known as 'Meteor Crater') is a gigantic hole in the middle of the arid sandstone of the Arizona desert. A rim of smashed and jumbled boulders, some of them the size of small houses, rises 50 m above the level of the surrounding plain. The crater itself is nearly a 1500 m wide, and 180 m deep. When Europeans first discovered the crater, the plain around it was covered with chunks of meteoritic iron - over 30 tons of it, scattered over an area 12 to 15 km in diameter. Scientists now believe that the crater was created approximately 50,000 years ago. The meteorite which made it was composed almost entirely of nickel-iron, suggesting that it may have originated in the interior of a small planet. It was 50 m across, weighed roughly 300,000 tons, and was traveling at a speed of 65,000 km per hour. This ASTER 3-D perspective view was created by draping an ASTER bands 3-2-1image over a digital elevation model from the US Geological Survey National Elevation Dataset.This image was acquired on May 17, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along

  13. Elastic Anisotropy of Basalt

    Science.gov (United States)

    Becker, K.; Shapiro, S.; Stanchits, S.; Dresen, G.; Kaselow, A.; Vinciguerra, S.

    2005-12-01

    Elastic properties of rocks are sensitive to changes of the in-situ stress and damage state. In particular, seismic velocities are strongly affected by stress-induced formation and deformation of cracks or shear-enhanced pore collapse. The effect of stress on seismic velocities as a result of pore space deformation in isotropic rock at isostatic compression may be expressed by the equation: A+K*P-B*exp (-D*P) (1), where P=Pc-Pp is the effective pressure, the pure difference between confining pressure and pore pressure. The parameter A, K, B and D describe material constants determined using experimental data. The physical meaning of the parameters is given by Shapiro (2003, in Geophysics Vol.68(Nr.2)). Parameter D is related to the stress sensitivity of the rock. A similar relation was derived by Shapiro and Kaselow (2005, in Geophysics in press) for weak anisotropic rocks under arbitrary load. They describe the stress dependent anisotropy in terms of Thomson's (1986, in Geophysics, Vol. 51(Nr.10)) anisotropy parameters ɛ and γ as a function of stress in the case of an initially isotropic rock: ɛ ∝ E2-E3, γ ∝ E3-E2 (2) with Ei=exp (D*Pi). The exponential terms Ei are controlled by the effective stress components Pi. To test this relation, we have conducted a series of triaxial compression tests on dry samples of initially isotropic Etnean Basalt in a servo-controlled MTS loading frame equipped with a pressure cell. Confining pressure was 60, 40 and 20 MPa. Samples were 5 cm in diameter and 10 cm in length. Elastic anisotropy was induced by axial compression of the samples through opening and growth of microcracks predominantly oriented parallel to the sample axis. Ultrasonic P- and S- wave velocities were monitored parallel and normal to the sample axis by an array of 20 piezoceramic transducers glued to the surface. Preamplified full waveform signals were stored in two 12 channel transient recorders. According to equation 2 the anisotropy parameters are

  14. Laser Raman Spectroscopic Characterization of Shocked Plagioclase from the Lonar Impact Crater, India.

    Science.gov (United States)

    Chakrabarti, R.; Basu, A. R.; Peterson, J.; Misra, S.

    2004-12-01

    We report Raman spectra of shocked plagioclase grains from the Lonar impact Crater of India. The Lonar Crater, located in the Buldana district of Maharashtra, India (19° 58'N, 76° 31'E), is an almost circular depression in the 65Ma old basalt flows of the Deccan Traps. Age estimates of this impact crater range from 10-50ka. Tektite and basalt samples were collected for this study from the rim of the crater, which is raised about 20 meters above the surrounding plains. For comparison, a Manicouagan maskelynite and an unaltered mid-oceanic ridge basalt with plagioclase laths were also analyzed. Polished thin sections of all these samples were first petrographically studied. The MORB plagioglase as well as the plagioclase from Lonar host-basalts show first order interference colors and distinct multiple lamellar twinning. The Manicouagan maskelynite is isotropic under crossed-polars. The Lonar tektite samples characteristically demonstrate spherules which are identified by their perfectly circular cross-section and isotropic nature. The spherules also contain fragments of the host basalt with plagioclase laths showing lamellar twinning. The groundmass within the spherules shows lath shaped plagioclase grains, most of which show varying degrees of isotropism due to maskelynitization. Raman scattering measurements were performed using the 514.5 nm line of an argon ion laser at an intensity of 40 kW/cm2. An inverted microscope (Nikon TE3000) with 50x objective (NA 0.55) was used for confocal imaging. A holographic notch filter removed residual laser scatter and the Raman scattering was detected by a silicon CCD at -90° C (Princeton Instruments Spec10-400R). Raman spectra were collected from ~250 cm-1 through 2000 cm-1. Raman spectra of crystalline unshocked plagioclase feldspars from the MORB and the Lonar host basalt show strongest peaks at 265 cm-1, 410 cm-1, 510 cm-1 and 1110 cm-1. The results remain the same for different points in a single grain but vary slightly

  15. Polygons near Lyot Crater

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-564, 4 December 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows patterned ground, arranged in the form of polygons, on the undulating plains associated with ejecta from the Lyot impact crater on the martian northern plains. This picture was acquired in October 2003 and shows that the polygon margins are ridges with large boulders--shown here as dark dots--on them. On Earth, polygon patterns like this are created in arctic and antarctic regions where there is ice in the ground. The seasonal and longer-term cycles of freezing and thawing of the ice-rich ground cause these features to form over time. Whether the same is true for Mars is unknown. The polygons are located near 54.6oN, 326.6oW. The image covers an area 3 km (1.9 mi) wide and is illuminated from the lower left.

  16. Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i

    Science.gov (United States)

    Swanson, Don; Wooten, Kelly M.; Orr, Tim R.

    2009-01-01

    The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations.The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.

  17. Geology of Lofn Crater, Callisto

    Science.gov (United States)

    Greeley, Ronald; Heiner, Sarah; Klemaszewski, James E.

    2001-01-01

    Lofn crater is a 180-km-diameter impact structure in the southern cratered plains of Callisto and is among the youngest features seen on the surface. The Lofn area was imaged by the Galileo spacecraft at regional-scale resolutions (875 m/pixel), which enable the general geology to be investigated. The morphology of Lofn crater suggests that (1) it is a class of impact structure intermediate between complex craters and palimpsests or (2) it formed by the impact of a projectile which fragmented before reaching the surface, resulting in a shallow crater (even for Callisto). The asymmetric pattern of the rim and ejecta deposits suggests that the impactor entered at a low angle from the northwest. The albedo and other characteristics of the ejecta deposits from Lofn also provide insight into the properties of the icy lithosphere and subsurface configuration at the time of impact. The "target" for the Lofn impact is inferred to have included layered materials associated with the Adlinda multiring structure northwest of Loh and ejecta deposits from the Heimdall crater area to the southeast. The Lofn impact might have penetrated through these materials into a viscous substrate of ductile ice or possibly liquid water. This interpretation is consistent with models of the current interior of Callisto based on geophysical information obtained from the Galileo spacecraft.

  18. Aqueous Alteration of Endeavour Crater Rim Apron Rocks

    Science.gov (United States)

    Ming, D. W.; Mittlefehldt, D. W.; Gellert, R.; Clark, B. C.; Morris, R. V.; Yen, A. S.; Arvidson, R. E.; Crumpler, L. S.; Farrand, W. H.; Grant, J. A., III; Jolliff, B. L.; Parker, T. J.; Peretyazhko, T.

    2014-12-01

    Mars Exploration Rover Opportunity is exploring Noachian age rocks of the rim of 22 km diameter Endeavour crater. Overlying the pre-impact lithologies and rim breccias is a thin apron of fine-grained sediments, the Grasberg fm, forming annuli on the lower slopes of rim segments. Hesperian Burns fm sandstones overly the Grasberg fm. Grasberg rocks have major element compositions that are distinct from Burns fm sandstones, especially when comparing interior compositions exposed by the Rock Abrasion Tool. Grasberg rocks are also different from Endeavour rim breccias, but have general compositional similarities to them. Grasberg sediments are plausibly fine-grained materials derived from the impact breccias. Veins of CaSO4 transect Grasberg fm rocks demonstrating post-formation aqueous alteration. Minor/trace elements show variations consistent with mobilization by aqueous fluids. Grasberg fm rocks have low Mn and high Fe/Mn ratios compared to the other lithologies. Manganese likely was mobilized and removed from the Grasberg host rock by redox reactions. We posit that Fe2+ from acidic solutions associated with formation of the Burns sulfate-rich sandstones acted as an electron donor to reduce more oxidized Mn to Mn2+. The Fe contents of Grasberg rocks are slightly higher than in other rocks suggesting precipitation of Fe phases in Grasberg materials. Pancam spectra show that Grasberg rocks have a higher fraction of ferric oxide minerals than other Endeavour rim rocks. Solutions transported Mn2+ into the Endeavour rim materials and oxidized and/or precipitated it in them. Grasberg has higher contents of the mobile elements K, Zn, Cl, and Br compared to the rim materials. Similar enrichments of mobile elements were measured by the Spirit APXS on West Spur and around Home Plate in Gusev crater. Enhancements in these elements are attributed to interactions of hydrothermal acidic fluids with the host rocks. Interactions of fluids with the Grasberg fm postdate the genesis

  19. A Tale of 3 Craters

    Science.gov (United States)

    2004-01-01

    11 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the complexity of the martian upper crust. Mars does not simply have an impact-cratered surface, it's upper crust is a cratered volume. Over time, older craters on Mars have been eroded, filled, buried, and in some cases exhumed and re-exposed at the martian surface. The crust of Mars is layered to depths of 10 or more kilometers, and mixed in with the layered bedrock are a variety of ancient craters with diameters ranging from a few tens of meters (a few tens of yards) to several hundred kilometers (more than one or two hundred miles). The picture shown here captures some of the essence of the layered, cratered volume of the upper crust of Mars in a very simple form. The image shows three distinct circular features. The smallest, in the lower right quarter of the image, is a meteor crater surrounded by a mound of material. This small crater formed within a layer of bedrock that once covered the entire scene, but today is found only in this small remnant adjacent to the crater. The intermediate-sized crater, west (left) of the small one, formed either in the next layer down--that is, below the layer in which the small crater formed--or it formed in some layers that are now removed, but was big enough to penetrate deeply into the rock that is near the surface today. The largest circular feature in the image, in the upper right quarter of the image, is still largely buried. It formed in layers of rock that are below the present surface. Erosion has brought traces of its rim back to the surface of Mars. This picture is located near 50.0oS, 77.8oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this October 2004 image from the upper left.

  20. Stability of nuclear crater slopes in rock

    International Nuclear Information System (INIS)

    Fleming, Robert W.; Frandsen, Alton D.; LaFrenz, Robert L.

    1970-01-01

    The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects

  1. Stability of nuclear crater slopes in rock

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Robert W; Frandsen, Alton D; LaFrenz, Robert L [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)

    1970-05-15

    The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects.

  2. Moon - 'Ghost' craters formed during Mare filling.

    Science.gov (United States)

    Cruikshank, D. P.; Hartmann, W. K.; Wood, C. A.

    1973-01-01

    This paper discusses formation of 'pathological' cases of crater morphology due to interaction of craters with molten lavas. Terrestrial observations of such a process are discussed. In lunar maria, a number of small impact craters (D less than 10 km) may have been covered by thin layers of fluid lavas, or formed in molten lava. Some specific lunar examples are discussed, including unusual shallow rings resembling experimental craters deformed by isostatic filling.

  3. Meteor Crater (Barringer Meteorite Crater), Arizona: Summary of Impact Conditions

    Science.gov (United States)

    Roddy, D. J.; Shoemaker, E. M.

    1995-09-01

    Meteor Crater in northern Arizona represents the most abundant type of impact feature in our Solar System, i.e., the simple bowl-shaped crater. Excellent exposures and preservation of this large crater and its ejecta blanket have made it a critical data set in both terrestrial and planetary cratering research. Recognition of the value of the crater was initiated in the early 1900's by Daniel Moreau Barringer, whose 27 years of exploration championed its impact origin [1]. In 1960, Shoemaker presented information that conclusively demonstrated that Meteor Crater was formed by hypervelocity impact [2]. This led the U.S. Geological Survey to use the crater extensively in the 1960-70's as a prime training site for the Apollo astronauts. Today, Meteor Crater continues to serve as an important research site for the international science community, as well as an educational site for over 300,000 visitors per year. Since the late 1950's, studies of this crater have presented an increasingly clearer view of this impact and its effects and have provided an improved view of impact cratering in general. To expand on this data set, we are preparing an upgraded summary on the Meteor Crater event following the format in [3], including information and interpretations on: 1) Inferred origin and age of the impacting body, 2) Inferred ablation and deceleration history in Earth's atmosphere, 3) Estimated speed, trajectory, angle of impact, and bow shock conditions, 4) Estimated coherence, density, size, and mass of impacting body, 5) Composition of impacting body (Canyon Diablo meteorite), 6) Estimated kinetic energy coupled to target rocks and atmosphere, 7) Terrain conditions at time of impact and age of impact, 8) Estimated impact dynamics, such as pressures in air, meteorite, and rocks, 9) Inferred and estimated material partitioning into vapor, melt, and fragments, 10) Crater and near-field ejecta parameters, 11) Rock unit distributions in ejecta blanket, 12) Estimated far

  4. Subseafloor basalts as fungal habitats

    Science.gov (United States)

    Ivarsson, M.; Bengtson, S.

    2013-12-01

    The oceanic crust makes up the largest potential habitat for life on Earth, yet next to nothing is known about the abundance, diversity and ecology of its biosphere. Our understanding of the deep biosphere of subseafloor crust is, with a few exceptions, based on a fossil record. Surprisingly, a majority of the fossilized microorganisms have been interpreted or recently re-interpreted as remnants of fungi rather than prokaryotes. Even though this might be due to a bias in fossilization the presence of fungi in these settings can not be neglected. We have examined fossilized microorganisms in drilled basalt samples collected at the Emperor Seamounts in the Pacific Ocean. Synchrotron-radiation X-ray tomography microscopy (SRXTM) studies has revealed a complex morphology and internal structure that corresponds to characteristic fungal morphology. Chitin was detected in the fossilized hyphae, which is another strong argument in favour of a fungal interpretation. Chitin is absent in prokaryotes but a substantial constituent in fungal cell walls. The fungal colonies consist of both hyphae and yeast-like growth states as well as resting structures and possible fruit bodies, thus, the fungi exist in vital colonies in subseafloor basalts. The fungi have also been involved in extensive weathering of secondary mineralisations. In terrestrial environments fungi are known as an important geobiological agent that promotes mineral weathering and decomposition of organic matter, and they occur in vital symbiosis with other microorganisms. It is probable to assume that fungi would play a similar role in subseafloor basalts and have great impact on the ecology and on biogeochemical cycles in such environments.

  5. Stratigraphy of the crater Copernicus

    Science.gov (United States)

    Paquette, R.

    1984-01-01

    The stratigraphy of copernicus based on its olivine absorption bands is presented. Earth based spectral data are used to develop models that also employ cratering mechanics to devise theories for Copernican geomorphology. General geologic information, spectral information, upper and lower stratigraphic units and a chart for model comparison are included in the stratigraphic analysis.

  6. Basaltic cannibalism at Thrihnukagigur volcano, Iceland

    Science.gov (United States)

    Hudak, M. R.; Feineman, M. D.; La Femina, P. C.; Geirsson, H.

    2014-12-01

    Magmatic assimilation of felsic continental crust is a well-documented, relatively common phenomenon. The extent to which basaltic crust is assimilated by magmas, on the other hand, is not well known. Basaltic cannibalism, or the wholesale incorporation of basaltic crustal material into a basaltic magma, is thought to be uncommon because basalt requires more energy than higher silica rocks to melt. Basaltic materials that are unconsolidated, poorly crystalline, or palagonitized may be more easily ingested than fully crystallized massive basalt, thus allowing basaltic cannibalism to occur. Thrihnukagigur volcano, SW Iceland, offers a unique exposure of a buried cinder cone within its evacuated conduit, 100 m below the main vent. The unconsolidated tephra is cross-cut by a NNE-trending dike, which runs across the ceiling of this cave to a vent that produced lava and tephra during the ~4 Ka fissure eruption. Preliminary petrographic and laser ablation inductively coupled mass spectrometry (LA-ICP-MS) analyses indicate that there are two populations of plagioclase present in the system - Population One is stubby (aspect ratio 2.1), subhedral to euhedral, and has much higher Ba/Sr ratios. Population One crystals are observed in the cinder cone, dike, and surface lavas, whereas Population Two crystals are observed only in the dike and surface lavas. This suggests that a magma crystallizing a single elongate population of plagioclase intruded the cinder cone and rapidly assimilated the tephra, incorporating the stubbier population of phenocrysts. This conceptual model for basaltic cannibalism is supported by field observations of large-scale erosion upward into the tephra, which is coated by magma flow-back indicating that magma was involved in the thermal etching. While the unique exposure at Thrihnukagigur makes it an exceptional place to investigate basaltic cannibalism, we suggest that it is not limited to this volcanic system. Rather it is a process that likely

  7. A field investigation of the basaltic ring structures of the Channeled Scabland and the relevance to Mars

    Science.gov (United States)

    Kestay, Laszlo P.; Jaeger, Windy L.

    2015-01-01

    The basaltic ring structure (BRS) is a class of peculiar features only reported in the Channeled Scabland of eastern Washington State. They have been suggested to be good analogs, however, for some circular features on Mars. BRSs are found where Pleistocene floods scoured the Columbia River Basin, stripping off the uppermost part of the Miocene Columbia River Basalt Group and exposing structures that were previously embedded in the lava. The “Odessa Craters,” near Odessa, WA, are 50–500-m-wide BRSs that are comprised of discontinuous, concentric outcrops of subvertically-jointed basalt and autointrusive dikes. Detailed field investigation of the Odessa Craters in planform and a cross-sectional exposure of a similar structure above Banks Lake, WA, lead us to propose that BRSs formed by concurrent phreatovolcanism and lava flow inflation. In this model, phreatovolcanic (a.k.a., “rootless”) cones formed on a relatively thin, active lava flow; the lava flow inflated around the cones, locally inverting topography; tensile stresses caused concentric fracturing of the lava crust; lava from within the molten interior of the flow exploited the fractures and buried the phreatovolcanic cones; and subsequent erosive floods excavated the structures. Another population of BRSs near Tokio Station, WA, consists of single-ringed, raised-rimmed structures that are smaller and more randomly distributed than the Odessa Craters. We find evidence for a phreatovolcanic component to the origin as well, and hypothesize that they are either flood-eroded phreatovolcanic cones or Odessa Crater-like BRSs. This work indicates that BRSs are not good analogs to the features on Mars because the martian features are found on the uneroded surfaces. Despite this, the now superseded concepts for BRS formation are useful for understanding the formation of the martian features.

  8. Lunar Bouguer gravity anomalies - Imbrian age craters

    Science.gov (United States)

    Dvorak, J.; Phillips, R. J.

    1978-01-01

    The Bouguer gravity of mass anomalies associated with four Imbrian age craters, analyzed in the present paper, are found to differ considerably from the values of the mass anomalies associated with some young lunar craters. Of the Imbrian age craters, only Piccolomini exhibits a negative gravity anomaly (i.e., a low density region) which is characteristic of the young craters studied. The Bouguer gravity anomalies are zero for each of the remaining Imbrian age craters. Since, Piccolomini is younger, or at least less modified, than the other Imbrian age craters, it is suggested that the processes responsible for the post-impact modification of the Imbrian age craters may also be responsible for removing the negative mass anomalies initially associated with these features.

  9. Crater Degradation on Mercury: A Global Perspective

    Science.gov (United States)

    Kinczyk, M. J.; Byrne, P. K.; Prockter, L. M.; Susorney, H. C. M.; Chapman, C. R.; Barnouin, O. S.

    2017-12-01

    On geologic timescales, initially fresh craters are subjected to many weathering mechanisms. Whereas water and wind are, or were, effective erosive mechanisms such as on Earth and Mars, micrometeorite bombardment and modification due to subsequent impacts are the dominant processes that degrade craters and crater rays on airless bodies like the Moon and Mercury. Classifying craters based on their state of degradation can help determine the relative ages of landforms proximal to, and crosscut by, these craters. However, this method is most effective when used together with statistical analysis of crater distributions. Pre-MESSENGER degradation classification schemes lacked sufficient detail to be consistently applied to craters of various sizes and morphological types—despite evidence suggesting that the ejecta deposits of large basins persist much longer than those of smaller craters, for instance—yet broad assumptions have been made regarding the correlation of crater class to the planet's time-stratigraphic sequence. Moreover, previous efforts to categorize craters by degradation state have either been restricted to regional study sites or applied only to a subset of crater age or size. As a result, numerous interpretations of crater degradation state persist for Mercury, challenging a complete understanding of this process on the innermost planet. We report on the first global survey of crater degradation on Mercury. By modifying an established 5-class scheme, we have systematically applied a rigorous set of criteria to all craters ≥40 km in diameter on the planet. These criteria include the state and morphology of crater deposits separately (e.g., rim, floor, wall, ejecta) and degradation classes were assigned as the collection of these individual attributes. This approach yields a consistent classification of craters of different sizes. Our results provide the first comprehensive assessment of how craters of various states of degradation are distributed

  10. Wind-Eroded Crater Floors and Intercrater Plains, Terra Sabaea, Mars

    Science.gov (United States)

    Irwin, Rossman P.; Wray, James J.; Mest, Scott C.; Maxwell, Ted A.

    2018-02-01

    Ancient impact craters with wind-eroded layering on their floors provide a record of resurfacing materials and processes on early Mars. In a 54 km Noachian crater in Terra Sabaea (20.2°S, 42.6°E), eolian deflation of a friable, dark-toned layer up to tens of meters thick has exposed more resistant, underlying light-toned material. These layers differ significantly from strata of similar tone described in other regions of Mars. The light-toned material has no apparent internal stratification, and visible/near-infrared spectral analysis suggests that it is rich in feldspar. Its origin is ambiguous, as we cannot confidently reject igneous, pyroclastic, or clastic alternatives. The overlying dark-toned layer is probably a basaltic siltstone or sandstone that was emplaced mostly by wind, although its weak cementation and inverted fluvial paleochannels indicate some modification by water. Negative-relief channels are not found on the crater floor, and fluvial erosion is otherwise weakly expressed in the study area. Small impacts onto this crater's floor have exposed deeper friable materials that appear to contain goethite. Bedrock outcrops on the crater walls are phyllosilicate bearing. The intercrater plains contain remnants of a post-Noachian thin, widespread, likely eolian mantle with an indurated surface. Plains near Hellas-concentric escarpments to the north are more consistent with volcanic resurfacing. A 48 km crater nearby contains similar dark-over-light outcrops but no paleochannels. Our findings indicate that dark-over-light stratigraphy has diverse origins across Mars and that some dark-toned plains with mafic mineralogy are not of igneous origin.

  11. The Influence of Topographic Obstacles on Basaltic Lava Flow Morphologies

    Science.gov (United States)

    von Meerscheidt, H. C.; Brand, B. D.; deWet, A. P.; Bleacher, J. E.; Hamilton, C. W.; Samuels, R.

    2014-12-01

    Smooth pāhoehoe and jagged ´áā represent two end-members of a textural spectrum that reflects the emplacement characteristics of basaltic lava flows. However, many additional textures (e.g., rubbly and slabby pāhoehoe) reflect a range of different process due to lava flow dynamics or interaction with topography. Unfortunately the influence of topography on the distribution of textures in basaltic lava flows is not well-understood. The 18 ± 1.0 ka Twin Craters lava flow in the Zuni-Bandera field (New Mexico, USA) provides an excellent site to study the morphological changes of a lava flow that encountered topographic obstacles. The flow field is 0.2-3.8 km wide with a prominent central tube system that intersects and wraps around a 1000 m long ridge, oriented perpendicular to flow. Upstream of the ridge, the flow has low-relief inflation features extending out and around the ridge. This area includes mildly to heavily disrupted pāhoehoe with interdispersed agglutinated masses, irregularly shaped rubble and lava balls. Breakouts of ´áā and collapse features are also common. These observations suggest crustal disruption due to flow-thickening upstream from the ridge and the movement of lava out and around the obstacle. While the ridge influenced the path of the tube, which wraps around the southern end of the ridge, the series of collapse features and breakouts of ´áā along the tube system are more likely a result of changes in flux throughout the tube system because these features are found both upstream and downstream of the obstacle. This work demonstrates that topography can significantly influence the formation history and surface disruption of a flow field, and in some cases the influence of topography can be separated from the influences of changes in flux along a tube system.

  12. Dissolution Rates of Allophane, FE-Containing Allophane, and Hisingerite and Implications for Gale Crater, Mars

    Science.gov (United States)

    Ralston, S. J.; Hausrath, E. M.; Tschauner, O.; Rampe, E. B.; Christoffersen, R.

    2018-01-01

    Investigations with the CheMin Xray Diffractometer (XRD) onboard the Curiosity rover in Gale Crater demonstrate that all rock and soil samples measured to date contain approximately 15-70 weight percentage X-ray amorphous materials. The diffuse scattering hump from the X-ray amorphous materials in CheMin XRD patterns can be fit with a combination of allophane, ferrihydrite, and rhyolitic and basaltic glass. Because of the iron-rich nature of Mars' surface, Fe-rich poorly-crystalline phases, such as hisingerite, may be present in addition to allophane.

  13. Subseafloor basalts as fungal habitats

    Directory of Open Access Journals (Sweden)

    M. Ivarsson

    2012-09-01

    Full Text Available The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, still we lack substantial information about the abundance, diversity, and consequence of its biosphere. The last two decades have involved major research accomplishments within this field and a change in view of the ocean crust and its potential to harbour life. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (∼50–200 µm in diameter body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate-forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few µm to ∼20 µm in diameter are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma.

  14. Monogenetic origin of Ubehebe Crater maar volcano, Death Valley, California: Paleomagnetic and stratigraphic evidence

    Science.gov (United States)

    Champion, Duane E.; Cyr, Andy; Fierstein, Judy; Hildreth, Wes

    2018-04-01

    Paleomagnetic data for samples collected from outcrops of basaltic spatter at the Ubehebe Crater cluster, Death Valley National Park, California, record a single direction of remanent magnetization indicating that these materials were emplaced during a short duration, monogenetic eruption sequence 2100 years ago. This conclusion is supported by geochemical data encompassing a narrow range of oxide variation, by detailed stratigraphic studies of conformable phreatomagmatic tephra deposits showing no evidence of erosion between layers, by draping of sharp rimmed craters by later tephra falls, and by oxidation of later tephra layers by the remaining heat of earlier spatter. This model is also supported through a reinterpretation and recalculation of the published 10Be age results (Sasnett et al., 2012) from an innovative and bold exposure-age study on very young materials. Their conclusion of multiple and protracted eruptions at Ubehebe Crater cluster is here modified through the understanding that some of their quartz-bearing clasts inherited 10Be from previous exposure on the fan surface (too old), and that other clasts were only exposed at the surface by wind and/or water erosion centuries after their eruption (too young). Ubehebe Crater cluster is a well preserved example of young monogenetic maar type volcanism protected within a National Park, and it represents neither a protracted eruption sequence as previously thought, nor a continuing volcanic hazard near its location.

  15. Mineralogy of Rocks and Sediments at Gale Crater, Mars

    Science.gov (United States)

    Achilles, Cherie; Downs, Robert; Blake, David; Vaniman, David; Ming, Doug; Rampe, Elizabeth; Morris, Dick; Morrison, Shaunna; Treiman, Allan; Chipera, Steve; Yen, Albert; Bristow, Thomas; Craig, Patricia; Hazen, Robert; Crisp, Joy; Grotzinger, John; Des Marias, David; Farmer, Jack; Sarrazin, Philippe; Morookian, John Michael

    2017-04-01

    The Mars Science Laboratory rover, Curiosity, is providing in situ mineralogical, geochemical, and sedimentological assessments of rocks and soils in Gale crater. Since landing in 2012, Curiosity has traveled over 15 km, providing analyses of mudstones and sandstones to build a stratigraphic history of the region. The CheMin X-ray diffraction (XRD) instrument is the first instrument on Mars to provide quantitative mineralogical analyses of drilled powders and scooped sediment based on X-ray crystallography. CheMin identifies and determines mineral abundances and unit-cell parameters of major crystalline phases, and identifies minor phases at abundances >1 wt%. In conjunction with elemental analyses, CheMin-derived crystal chemistry allows for the first calculations of crystalline and amorphous material compositions. These mineralogy, crystal chemistry, and amorphous chemistry datasets are playing central roles in the characterization of Gale crater paleoenvironments. CheMin has analyzed 17 rock and sediment samples. In the first phase of the mission, Curiosity explored the sedimentary units of Aeolis Palus (Bradbury group), including two mudstones from Yellowknife Bay. CheMin analyses of the Yellowknife Bay mudstones identified clay minerals among an overall basaltic mineral assemblage. These mineralogical results, along with imaging and geochemical analyses, were used to characterize an ancient lacustrine setting that is thought to have once been a habitable environment. Following the investigations of the Bradbury group, Curiosity arrived at the lower reaches of Aeolis Mons, commonly called Mt. Sharp. A strategic sample campaign was initiated, drilling bedrock at X-ray amorphous phases. Adjacent to fractures, light-toned, halo-like zones are thought to result from significant aqueous alteration of the primary sandstone and show decreased abundances of feldspar and pyroxene, and an increase in the amorphous component, specifically high-silica phases. The Murray

  16. Experimental research on continuous basalt fiber and basalt-fibers-reinforced polymers

    Science.gov (United States)

    Zhang, Xueyi; Zou, Guangping; Shen, Zhiqiang

    2008-11-01

    The interest for continuous basalt fibers and reinforced polymers has recently grown because of its low price and rich natural resource. Basalt fiber was one type of high performance inorganic fibers which were made from natural basalt by the method of melt extraction. This paper discusses basic mechanical properties of basalt fiber. The other work in this paper was to conduct tensile testing of continuous basalt fiber-reinforced polymer rod. Tensile strength and stress-strain curve were obtained in this testing. The strength of rod was fairly equal to rod of E-glass fibers and weaker than rod of carbon fibers. Surface of crack of rod was studied. An investigation of fracture mechanism between matrix and fiber was analyzed by SEM (Scanning electron microscopy) method. A poor adhesion between the matrix and fibers was also shown for composites analyzing SEM photos. The promising tensile properties of the presented basalt fibers composites have shown their great potential as alternative classical composites.

  17. Geologic structure of the eastern mare basins. [lunar basalts

    Science.gov (United States)

    Dehon, R. A.; Waskom, J. D.

    1976-01-01

    The thickness of mare basalts in the eastern maria are estimated and isopachs of the basalts are constructed. Sub-basalt basin floor topography is determined, and correlations of topographic variations of the surface with variations in basalt thickness or basin floor topography are investigated.

  18. The Origin of Noble Gas Isotopic Heterogeneity in Icelandic Basalts

    Science.gov (United States)

    Dixon, E. T.; Honda, M.; McDougall, I.

    2001-01-01

    Two models for generation of heterogeneous He, Ne and Ar isotopic ratios in Icelandic basalts are evaluated using a mixing model and the observed noble gas elemental ratios in Icelandic basalts,Ocean island Basalt (OIBs) and Mid-Ocean Ridge Basalt (MORBs). Additional information is contained in the original extended abstract.

  19. Basalt waste added to Portland cement

    Directory of Open Access Journals (Sweden)

    Thiago Melanda Mendes

    2016-08-01

    Full Text Available Portland cement is widely used as a building material and more than 4.3 billion tons were produced in 2014, with increasing environmental impacts by this industry, mainly through CO2 emissions and consumption of non-removable raw materials. Several by-products have been used as raw materials or fuels to reduce environmental impacts. Basaltic waste collected by filters was employed as a mineral mixture to Portland cement and two fractions were tested. The compression strength of mortars was measured after 7 days and Scanning Electron Microscopy (SEM and Electron Diffraction Scattering (EDS were carried out on Portland cement paste with the basaltic residue. Gains in compression strength were observed for mixtures containing 2.5 wt.% of basaltic residue. Hydration products observed on surface of basaltic particles show the nucleation effect of mineral mixtures. Clinker substitution by mineral mixtures reduces CO2 emission per ton of Portland cement.

  20. Naming Lunar Mare Basalts: Quo Vadimus Redux

    Science.gov (United States)

    Ryder, G.

    1999-01-01

    Nearly a decade ago, I noted that the nomenclature of lunar mare basalts was inconsistent, complicated, and arcane. I suggested that this reflected both the limitations of our understanding of the basalts, and the piecemeal progression made in lunar science by the nature of the Apollo missions. Although the word "classification" is commonly attached to various schemes of mare basalt nomenclature, there is still no classification of mare basalts that has any fundamental grounding. We remain basically at a classification of the first kind in the terms of Shand; that is, things have names. Quoting John Stuart Mill, Shand discussed classification of the second kind: "The ends of scientific classification are best answered when the objects are formed into groups respecting which a greater number of propositions can be made, and those propositions more important than could be made respecting any other groups into which the same things could be distributed." Here I repeat some of the main contents of my discussion from a decade ago, and add a further discussion based on events of the last decade. A necessary first step of sample studies that aims to understand lunar mare basalt processes is to associate samples with one another as members of the same igneous event, such as a single eruption lava flow, or differentiation event. This has been fairly successful, and discrete suites have been identified at all mare sites, members that are eruptively related to each other but not to members of other suites. These eruptive members have been given site-specific labels, e.g., Luna24 VLT, Apollo 11 hi-K, A12 olivine basalts, and Apollo 15 Green Glass C. This is classification of the first kind, but is not a useful classification of any other kind. At a minimum, a classification is inclusive (all objects have a place) and exclusive (all objects have only one place). The answer to "How should rocks be classified?" is far from trivial, for it demands a fundamental choice about nature

  1. Size-Frequency Distribution of Small Lunar Craters: Widening with Degradation and Crater Lifetime

    Science.gov (United States)

    Ivanov, B. A.

    2018-01-01

    The review and new measurements are presented for depth/diameter ratio and slope angle evolution during small ( D model. The uncertainty of crater retention age due to crater degradational widening is estimated. The collected and analyzed data are discussed to be used in the future updating of mechanical models for lunar crater aging.

  2. Preliminary Results from Initial Investigations of Ceres' Cratering Record from Dawn Imaging Data

    Science.gov (United States)

    Schmedemann, Nico; Michael, Gregory; Ivanov, Boris A.; Kneissl, Thomas; Neesemann, Adrian; Hiesinger, Harald; Jaumann, Ralf; Raymond, Carol A.; Russell, Christopher T.

    2015-04-01

    The highly successful Dawn mission [1] finished data collection at Vesta in 2012 and is now on its way to the dwarf planet Ceres. According to the current Ceres approach timeline of the Dawn mission, the ground resolution of the Dawn FC camera [2] will be about 10 times better than Hubble data [3] at the time of the presentation of this work. This may allow for identification of craters about 15 km in diameter. Initial mapping of sample areas may provide enough information of the cratering record in order to compare it with the theoretical Ceres crater production function we present at the 46th LPSC conference (March 16-20, 2015, The Woodlands, Texas) [4]. Our preliminary crater production function for Ceres is derived from the assumption of an icy crust just below a thin surface layer of dust [5], and a projectile population that is very similar to the one that impacted the Moon [6]. In order to scale the lunar cratering record to Ceres we use the Ivanov scaling laws [7], which allow for crater scaling based on parameters that can be derived from observations. The lunar-like approach gave reasonable good results for the crater production function on the asteroids Vesta, Ida, Lutetia and Gaspra [8]. Since the lunar surface is of basaltic composition, the correct scaling between the different materials is challenging. One crucial parameter is the transition diameter from simple to complex craters. Based on the simple to complex transition diameter on Iapetus, an icy satellite of Saturn, we expect this transition at about 12 km crater size at Ceres. This value may be slightly different due to the different temperatures at Ceres and Iapetus. If the simple to complex transition is observed at much larger diameters, the reason could be a substantial fraction of rock in the shallow subsurface of Ceres. In an ice-rich surface material high relaxation rates may also be expected that could change the shape of the crater production function. A thorough geological mapping

  3. Hydrothermal evolution of repository groundwaters in basalt

    International Nuclear Information System (INIS)

    Apps, J.A.

    1984-01-01

    Groundwaters in the near field of a radioactive waste repository in basalt will change their chemical composition in response to reactions with the basalt. These reactions will be promoted by the heat generated by the decaying waste. It is important to predict both the rate and the extent of these reactions, and the secondary minerals produced, because the alteration process controls the chemical environment affecting the corrosion of the canister, the solubility and complexation of migrating radionuclides, the reactivity of the alteration products to radionuclides sorption, and the porosity and permeability of the host rock. A comprehensive review of the literature leads to the preliminary finding that hydrothermally altering basalts in geothermal regions such as Iceland lead to a secondary mineralogy and groundwater composition similar to that expected to surround a repository. Furthermore, laboratory experiments replicating the alteration conditions approximate those observed in the field and expected in a repository. Preliminary estimates were made of the rate of hydration and devitrification of basaltic glass and the zero-order dissolution rate of basaltic materials. The rates were compared with those for rhyolitic glasses and silicate minerals. Preliminary calculations made of mixed process alteration kinetics, involving pore diffusion and surface reaction suggest that at temperatures greater than 150 0 C, alteration proceeds so rapidly as to become pervasive in normally fractured basalt exposed to higher temperatures in the field. 70 references

  4. Investigation of Secondary Craters in the Saturnian System

    Science.gov (United States)

    Hoogenboom, T.; Schenk, P.; White, O. L.

    2012-03-01

    To derive accurate ages using impact craters, the impact source must be determined. We investigate secondary crater size, frequency, distribution, formation, and crater chain formation on icy satellites throughout the Jupiter and Saturn systems.

  5. Martian Low-Aspect-Ratio Layered Ejecta (LARLE) craters: Distribution, characteristics, and relationship to pedestal craters

    Science.gov (United States)

    Barlow, Nadine G.; Boyce, Joseph M.; Cornwall, Carin

    2014-09-01

    Low-Aspect-Ratio Layered Ejecta (LARLE) craters are a unique landform found on Mars. LARLE craters are characterized by a crater and normal layered ejecta pattern surrounded by an extensive but thin outer deposit which terminates in a sinuous, almost flame-like morphology. We have conducted a survey to identify all LARLE craters ⩾1-km-diameter within the ±75° latitude zone and to determine their morphologic and morphometric characteristics. The survey reveals 140 LARLE craters, with the majority (91%) located poleward of 40°S and 35°N and all occurring within thick mantles of fine-grained deposits which are likely ice-rich. LARLE craters range in diameter from the cut-off limit of 1 km up to 12.2 km, with 83% being smaller than 5 km. The radius of the outer LARLE deposit displays a linear trend with the crater radius and is greatest at higher polar latitudes. The LARLE deposit ranges in length between 2.56 and 14.81 crater radii in average extent, with maximum length extending up to 21.4 crater radii. The LARLE layer is very sinuous, with lobateness values ranging between 1.45 and 4.35. LARLE craters display a number of characteristics in common with pedestal craters and we propose that pedestal craters are eroded versions of LARLE craters. The distribution and characteristics of the LARLE craters lead us to propose that impact excavation into ice-rich fine-grained deposits produces a dusty base surge cloud (like those produced by explosion craters) that deposits dust and ice particles to create the LARLE layers. Salts emplaced by upward migration of water through the LARLE deposit produce a surficial duricrust layer which protects the deposit from immediate removal by eolian processes.

  6. What Really Happened to Earth's Older Craters?

    Science.gov (United States)

    Bottke, William; Mazrouei, Sara; Ghent, Rebecca; Parker, Alex

    2017-10-01

    Most assume the Earth’s crater record is heavily biased, with erosion/tectonics destroying older craters. This matches expectations, but is it actually true? To test this idea, we compared Earth’s crater record, where nearly all D ≥ 20 km craters are pick out from older craters with eroded fragments. Moreover, an inverse relationship between rock abundance (RA) and crater age exists. Using measured RA values, we computed ages for 111 rocky craters with D ≥ 10 km that formed between 80°N and 80°S over the last 1 Gyr.We found several surprising results. First, the production rate of D ≥ 10 km lunar craters increased by a factor of 2.2 [-0.9, +4.4; 95% confidence limits] over the past 250 Myr compared to the previous 750 Myr. Thus, the NEO population is higher now than it has been for the last billion years. Second, the size and age distributions of lunar and terrestrial craters for D ≥ 20 km over the last 650 Myr have similar shapes. This implies that crater erasure must be limited on stable terrestrial terrains; in an average sense, for a given region, the Earth either keeps all or loses all of its D ≥ 20 craters at the same rate, independent of size. It also implies the observed deficit of large terrestrial craters between 250-650 Myr is not preservation bias but rather reflects a distinctly lower impact flux. We predict 355 ± 86 D ≥ 20 km craters formed on Earth over the last 650 Myr. Only 38 ± 6 are known, so the ratio, 10.7 ± 3.1%, is a measure of the Earth’s surface that is reasonably stable to large crater formation over 650 Myr. If erosion had dominated, the age distribution of terrestrial craters would be strongly skewed toward younger ages, which is not observed. We predict Chicxulub-type impacts were rare over the last Gyr, with the event 66 Ma a probable byproduct of the current high terrestrial impact flux.

  7. Machine cataloging of impact craters on Mars

    Science.gov (United States)

    Stepinski, Tomasz F.; Mendenhall, Michael P.; Bue, Brian D.

    2009-09-01

    This study presents an automated system for cataloging impact craters using the MOLA 128 pixels/degree digital elevation model of Mars. Craters are detected by a two-step algorithm that first identifies round and symmetric topographic depressions as crater candidates and then selects craters using a machine-learning technique. The system is robust with respect to surface types; craters are identified with similar accuracy from all different types of martian surfaces without adjusting input parameters. By using a large training set in its final selection step, the system produces virtually no false detections. Finally, the system provides a seamless integration of crater detection with its characterization. Of particular interest is the ability of our algorithm to calculate crater depths. The system is described and its application is demonstrated on eight large sites representing all major types of martian surfaces. An evaluation of its performance and prospects for its utilization for global surveys are given by means of detailed comparison of obtained results to the manually-derived Catalog of Large Martian Impact Craters. We use the results from the test sites to construct local depth-diameter relationships based on a large number of craters. In general, obtained relationships are in agreement with what was inferred on the basis of manual measurements. However, we have found that, in Terra Cimmeria, the depth/diameter ratio has an abrupt decrease at ˜38°S regardless of crater size. If shallowing of craters is attributed to presence of sub-surface ice, a sudden change in its spatial distribution is suggested by our findings.

  8. Impact craters in South America

    CERN Document Server

    Acevedo, Rogelio Daniel; Ponce, Juan Federico; Stinco, Sergio G

    2015-01-01

    A complete and updated catalogue of impact craters and structures in South America from 2014 is presented here. Approximately eighty proven, suspected and disproven structures have been identified by several sources in this continent. All the impact sites of this large continent have been exhaustively reviewed: the proved ones, the possible ones and some very doubtful. Many sites remain without a clear geological ""in situ"" confirmation and some of them could be even rejected. Argentina and Brazil are leading the list containing almost everything detected. In Bolivia, Chile, Colombia, Guyana,

  9. Basaltic substrate composition affects microbial community development and acts as a source of nutrients in the deep biosphere

    Science.gov (United States)

    Bailey, B.; Sudek, L.; Templeton, A.; Staudigel, H.; Tebo, B.; Moyer, C.; Davis, R.

    2006-12-01

    Studies of the oceanic crust over the past decade have revealed that in spite of the oligotrophic nature of this environment, a diverse biosphere is present in the upper 1 km of basaltic crust. The key energy source in this setting may be the high content of transistion metals (Fe, Mn) found in the basaltic glass, but in order to discover the role of Fe and Mn in the deep biosphere, we must first determine which microbes are present and how they attain the necessary metabolites for proliferation. Our work contributes to both questions through the use of molecular microbiology techniques and the exposure of specifically designed substrates on the ocean floor. Loihi Seamount off the southeast coast of the Big Island of Hawai'i provides a unique laboratory for the study of distribution and population of microbial communities associated with iron rich environments on the ocean floor. Iron oxide flocculent material (floc) dominates the direct and diffuse hydrothermal venting areas on Loihi which makes it a prime target for understanding the role of iron in biological systems in the deep biosphere. We collected iron oxide floc and basaltic glass from pillow basalts around several hydrothermal vents on the crater rim, within the pit crater Pele's Pit, and from deep off of the southern rift zone of Loihi using the HURL PISCES IV/V submersibles. We also deployed basaltic glass sand amended with various nutrients (phosphate, oxidized and reduced iron, manganese) and recovered them in subsequent years to determine how substrate composition affects community structure. We extracted DNA from both rock and iron flocs and used t-RFLP to obtain a genetic fingerprint of the microbial communities associated with each substrate. From olivine and tholeiitic basalt enrichments, it appears that substrate composition strongly influences microbial colonization and subsequent community development even when deployed in the same conditions. Culturing efforts have yielded several iron

  10. Geologic history of quartz-normative and olivine-normative basalts in the vicinity of Hadley Rille (Apollo 15)

    International Nuclear Information System (INIS)

    Grove, T.L.

    1985-01-01

    The geologic history of the quartz normative (QNB) and olivine normative (ONB) basalt types at Hadley Rille are discussed. A model for the geology of the mare basalts was constructed from a combination of field observations, sample chemistry, sample petrology and personal bias from terrestrial experience. The model proposes that the QNBs are the only mare lava type that is present as outcrop in the area traversed by the astronauts during the Apollo 15 mission. The returned QNB samples formed during a single eruptive phase of the Hadley Rille lava tube system. The ONB lavas are an exotic component transported to the site by a cratering event, or the ONBs are samples excavated from older are bedrock that was partly covered by the QNB lavas

  11. Technical problems and future cratering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Knox, J B [Lawrence Radiation Laboratory, Livermore, CA (United States)

    1969-07-01

    This paper reviews some of the key technical problems that remain to be solved in nuclear cratering technology. These include: (1) developing a broader understanding of the effects that material properties and water content of the earth materials around the shot have on cratering behavior, (2) extending the experimental investigation of retarc formation to include intermediate yields and various materials, and (3) improving our ability to predict the escape of radioactive material to the atmosphere to form the cloud source responsible for fallout. The formation processes of ejecta craters, retarcs, and subsidence craters are described in the light of our present understanding, and the major gaps in our understanding are indicated. Methods of calculating crater and retarc formation are discussed, with particular reference to the input information needed. Methods for calculating fallout are presented, and their shortcomings are discussed. A preliminary analysis of the safety factors associated with the presently proposed nuclear excavation concepts is presented. (author)

  12. Technical problems and future cratering experiments

    International Nuclear Information System (INIS)

    Knox, J.B.

    1969-01-01

    This paper reviews some of the key technical problems that remain to be solved in nuclear cratering technology. These include: (1) developing a broader understanding of the effects that material properties and water content of the earth materials around the shot have on cratering behavior, (2) extending the experimental investigation of retarc formation to include intermediate yields and various materials, and (3) improving our ability to predict the escape of radioactive material to the atmosphere to form the cloud source responsible for fallout. The formation processes of ejecta craters, retarcs, and subsidence craters are described in the light of our present understanding, and the major gaps in our understanding are indicated. Methods of calculating crater and retarc formation are discussed, with particular reference to the input information needed. Methods for calculating fallout are presented, and their shortcomings are discussed. A preliminary analysis of the safety factors associated with the presently proposed nuclear excavation concepts is presented. (author)

  13. Ponds, Flows, and Ejecta of Impact Cratering and Volcanism: A Remote Sensing Perspective of a Dynamic Moon

    Science.gov (United States)

    Stopar, Julie D.

    Both volcanism and impact cratering produce ejecta and associated deposits incorporating a molten rock component. While the heat sources are different (exogenous vs. endogenous), the end results are landforms with similar morphologies including ponds and flows of impact melt and lava around the central crater. Ejecta from both impact and volcanic craters can also include a high percentage of melted rock. Using Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC) images, crucial details of these landforms are finally revealed, suggesting a much more dynamic Moon than is generally appreciated. Impact melt ponds and flows at craters as small as several hundred meters in diameter provide empirical evidence of abundant melting during the impact cratering process (much more than was previously thought), and this melt is mobile on the lunar surface for a significant time before solidifying. Enhanced melt deposit occurrences in the lunar highlands (compared to the mare) suggest that porosity, target composition, and pre-existing topography influence melt production and distribution. Comparatively deep impact craters formed in young melt deposits connote a relatively rapid evolution of materials on the lunar surface. On the other end of the spectrum, volcanic eruptions have produced the vast, plains-style mare basalts. However, little was previously known about the details of small-area eruptions and proximal volcanic deposits due to a lack of resolution. High-resolution images reveal key insights into small volcanic cones (0.5-3 km in diameter) that resemble terrestrial cinder cones. The cones comprise inter-layered materials, spatter deposits, and lava flow breaches. The widespread occurrence of the cones in most nearside mare suggests that basaltic eruptions occur from multiple sources in each basin and/or that rootless eruptions are relatively common. Morphologies of small-area volcanic deposits indicate diversity in eruption behavior of lunar basaltic

  14. Asteroid families from cratering: Detection and models

    Science.gov (United States)

    Milani, A.; Cellino, A.; Knežević, Z.; Novaković, B.; Spoto, F.; Paolicchi, P.

    2014-07-01

    A new asteroid families classification, more efficient in the inclusion of smaller family members, shows how relevant the cratering impacts are on large asteroids. These do not disrupt the target, but just form families with the ejecta from large craters. Of the 12 largest asteroids, 8 have cratering families: number (2), (4), (5), (10), (87), (15), (3), and (31). At least another 7 cratering families can be identified. Of the cratering families identified so far, 7 have >1000 members. This imposes a remarkable change from the focus on fragmentation families of previous classifications. Such a large dataset of asteroids believed to be crater ejecta opens a new challenge: to model the crater and family forming event(s) generating them. The first problem is to identify which cratering families, found by the similarity of proper elements, can be formed at once, with a single collision. We have identified as a likely outcome of multiple collisions the families of (4), (10), (15), and (20). Of the ejecta generated by cratering, only a fraction reaches the escape velocity from the surviving parent body. The distribution of velocities at infinity, giving to the resulting family an initial position and shape in the proper elements space, is highly asymmetric with respect to the parent body. This shape is deformed by the Yarkovsky effect and by the interaction with resonances. All the largest asteroids have been subjected to large cratering events, thus the lack of a family needs to be interpreted. The most interesting case is (1) Ceres, which is not the parent body of the nearby family of (93). Two possible interpretations of the low family forming efficiency are based on either the composition of Ceres with a significant fraction of ice, protected by a thin crust, or with the larger escape velocity of ~500 m/s.

  15. High concentrations of manganese and sulfur in deposits on Murray Ridge, Endeavour Crater, Mars

    Science.gov (United States)

    Arvidson, Raymond E.; Squyres, Steven W.; Morris, Richard V.; Knoll, Andrew H.; Gellert, Ralf; Clark, Benton C.; Catalano, Jeffrey G.; Jolliff, Bradley L.; McLennan, Scott M.; Herkenhoff, Kenneth E.; VanBommel, Scott; Mittelfehldt, David W.; Grotzinger, John P.; Guinness, Edward A.; Johnson, Jeffrey R.; Bell, James F.; Farrand, William H.; Stein, Nathan; Fox, Valerie K.; Golombek, Matthew P.; Hinkle, Margaret A. G.; Calvin, Wendy M.; de Souza, Paulo A.

    2016-01-01

    Mars Reconnaissance Orbiter HiRISE images and Opportunity rover observations of the ~22 km wide Noachian age Endeavour Crater on Mars show that the rim and surrounding terrains were densely fractured during the impact crater-forming event. Fractures have also propagated upward into the overlying Burns formation sandstones. Opportunity’s observations show that the western crater rim segment, called Murray Ridge, is composed of impact breccias with basaltic compositions, as well as occasional fracture-filling calcium sulfate veins. Cook Haven, a gentle depression on Murray Ridge, and the site where Opportunity spent its sixth winter, exposes highly fractured, recessive outcrops that have relatively high concentrations of S and Cl, consistent with modest aqueous alteration. Opportunity’s rover wheels serendipitously excavated and overturned several small rocks from a Cook Haven fracture zone. Extensive measurement campaigns were conducted on two of them: Pinnacle Island and Stuart Island. These rocks have the highest concentrations of Mn and S measured to date by Opportunity and occur as a relatively bright sulfate-rich coating on basaltic rock, capped by a thin deposit of one or more dark Mn oxide phases intermixed with sulfate minerals. We infer from these unique Pinnacle Island and Stuart Island rock measurements that subsurface precipitation of sulfate-dominated coatings was followed by an interval of partial dissolution and reaction with one or more strong oxidants (e.g., O2) to produce the Mn oxide mineral(s) intermixed with sulfate-rich salt coatings. In contrast to arid regions on Earth, where Mn oxides are widely incorporated into coatings on surface rocks, our results demonstrate that on Mars the most likely place to deposit and preserve Mn oxides was in fracture zones where migrating fluids intersected surface oxidants, forming precipitates shielded from subsequent physical erosion.

  16. Investigations of Ceres's Craters with Straightened Rim

    Science.gov (United States)

    Frigeri, A.; De Sanctis, M. C.; Ammannito, E.; Raponi, A.; Formisano, M.; Ciarniello, M.; Magni, G.; Combe, J. P.; Marchi, S.; Raymond, C. A.; Schwartz, S. J.

    2017-12-01

    Dwarf planet Ceres hosts some geological features that are unique in the solar system because its composition, rich in aqueously-altered silicates, is usually found on full-size planets, whereas its mean radius is smaller than most natural satellites in the solar system. For example, the local high-albedo, carbonate-rich areas or faculaeare specific to Ceres; also, the absence of big impact crater structures is key to understand the overall mechanical behaviour of the Cerean crust. After the first findings of water ice occurring in the shadowed areas of craters on Ceres by the NASA/Dawn mission (1, 2), we analyzed the morphology of craters looking for features similar to the ones where the water ice composition has been detected analyzing the data from the VIR spectrometer (3). These craters fall outside of the family of polygonal craters which are mainly related to regional or global scale tectonics (4). We analyzed the morphology on the base of the global mosaic, the digital terrain model derived by using the stereo photogrammetry method and the single data frames of the Framing Camera. Our investigation started from crater Juling, which is characterized by a portion of the rim which forms a straight segment instead of a portion of a circle. This linear crater wall is also steep enough that it forms a cliff that is in the shadowed area in all images acquired by Dawn. Very smooth and bright deposits lay at the foot of this crater-wall cliff. Then, we identified several other craters, relatively fresh, with radius of 2 to 10 kilometers, showing one or two sectors of the crater-rim being truncated by a mass-wasting process, probably a rockfall. Our first analysis show that in the selected craters, the truncated sectors are always in the north-eastern sector of the rim for the craters in the southern hemisphere. Conversely, the craters on the northern hemisphere exhibit a truncated rim in their south-eastern sector. Although a more detailed analysis is mandatory

  17. Evidence for rapid topographic evolution and crater degradation on Mercury from simple crater morphometry

    Science.gov (United States)

    Fassett, Caleb I.; Crowley, Malinda C.; Leight, Clarissa; Dyar, M. Darby; Minton, David A.; Hirabayashi, Masatoshi; Thomson, Bradley J.; Watters, Wesley A.

    2017-06-01

    Examining the topography of impact craters and their evolution with time is useful for assessing how fast planetary surfaces evolve. Here, new measurements of depth/diameter (d/D) ratios for 204 craters of 2.5 to 5 km in diameter superposed on Mercury's smooth plains are reported. The median d/D is 0.13, much lower than expected for newly formed simple craters ( 0.21). In comparison, lunar craters that postdate the maria are much less modified, and the median crater in the same size range has a d/D ratio that is nearly indistinguishable from the fresh value. This difference in crater degradation is remarkable given that Mercury's smooth plains and the lunar maria likely have ages that are comparable, if not identical. Applying a topographic diffusion model, these results imply that crater degradation is faster by a factor of approximately two on Mercury than on the Moon, suggesting more rapid landform evolution on Mercury at all scales.Plain Language SummaryMercury and the Moon are both airless bodies that have experienced numerous impact events over billions of years. These impacts form craters in a geologic instant. The question examined in this manuscript is how fast these craters erode after their formation. To simplify the problem, we examined craters of a particular size (2.5 to 5 km in diameter) on a particular geologic terrain type (volcanic smooth plains) on both the Moon and Mercury. We then measured the topography of hundreds of craters on both bodies that met these criteria. Our results suggest that craters on Mercury become shallower much more quickly than craters on the Moon. We estimate that Mercury's topography erodes at a rate at least a factor of two faster than the Moon's.

  18. Geochemical evidence for waning magmatism and polycyclic volcanism at Crater Flat, Nevada

    International Nuclear Information System (INIS)

    Perry, F.V.; Crowe, B.M.

    1992-01-01

    This paper reports that petrologic and geochemical studies of basaltic rocks in the Yucca Mountain region are currently focused on understanding the evolution of volcanism in the Crater Flat volcanic field and the mechanisms of polycyclic volcanic field and the mechanisms of polycyclic volcanism at the Lathrop Wells volcanic center, the youngest center in the Crater Flat volcanic field. Geochemical and petrologic data indicate that the magma chambers which supplied the volcanic centers at Crater Flat became situated at greater crustal depths as the field evolved. Deep magma chambers may be related to a waning magma flux that was unable to sustain upper crustal magma conduits and chambers. Geochemical data from the Lathrop Wells volcanic center indicate that eruptive units identified from field and geomorphic relationships are geochemically distinct. The geochemical variations cannot be explained by fractional crystallization of a single magma batch, indicating that several magma batches were involved in the formation of the Lathrop Wells center. Considering the low magma flux in the Yucca Mountain region in the Quaternary, the probability of several magma batches erupting essentially simultaneously at Lathrop Wells is considered remote

  19. Saying Goodbye to 'Bonneville' Crater

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Annotated Image NASA's Mars Exploration Rover Spirit took this panoramic camera image on sol 86 (March 31, 2004) before driving 36 meters (118 feet) on sol 87 toward its future destination, the Columbia Hills. This is probably the last panoramic camera image that Spirit will take from the high rim of 'Bonneville' crater, and provides an excellent view of the ejecta-covered path the rover has journeyed thus far. The lander can be seen toward the upper right of the frame and is approximately 321 meters (1060 feet) away from Spirit's current location. The large hill on the horizon is Grissom Hill. The Colombia Hills, located to the left, are not visible in this image.

  20. SMALL CRATERS AND THEIR DIAGNOSTIC POTENTIAL

    Directory of Open Access Journals (Sweden)

    R. Bugiolacchi

    2017-07-01

    Full Text Available I analysed and compared the size-frequency distributions of craters in the Apollo 17 landing region, comprising of six mare terrains with varying morphologies and cratering characteristics, along with three other regions allegedly affected by the same secondary event (Tycho secondary surge. I propose that for the smaller crater sizes (in this work 9–30 m, a] an exponential curve of power −0.18D can approximate Nkm−2 crater densities in a regime of equilibrium, while b] a power function D−3 closely describes the factorised representation of craters by size (1 m. The saturation level within the Central Area suggests that c] either the modelled rates of crater erosion on the Moon should be revised, or that the Tycho event occurred much earlier in time than the current estimate. We propose that d] the size-frequency distribution of small secondary craters may bear the signature (in terms of size-frequency distribution of debris/surge of the source impact and that this observation should be tested further.

  1. Implications of one-year basalt weathering/reactivity study for a basalt repository environment

    International Nuclear Information System (INIS)

    Pine, G.L.; Jantzen, C.M.

    1987-03-01

    The Savannah River Laboratory is testing the performance of the Defense Waste Processing Facility glass under conditions representing potential repository environments. For a basalt repository, one of the important issues is how rapidly reducing conditions are re-established after placement of the waste. The objective of this study was to examine the factors affecting the reactivity of the basalt. Construction of a nuclear waste repository in basalt will temporarily perturb the groundwater conditions, creating more oxidizing (air-saturated) conditions than an undisturbed repository system. Reducing conditions can be beneficial to the performance of waste glass and canisters, and may limit the transport of certain radionuclides. The Basalt Waste Isolation Project intends to use a backfill containing crushed basalt to re-establish the reducing conditions of the groundwater. The reactivity of the basalt has been found to be minimal once the fresh crushed surfaces have been weathered and the reactive intergranular glass component has been leached, e.g., by long-term surface storage. Crushing of the basalt for pneumatic emplacement of the backfill should, therefore, occur shortly before placement in the repository. This backfill must contain a minimum of 5 percent reactive fines (<100 mesh), to rapidly achieve reducing conditions. 23 refs., 21 figs., 18 tabs

  2. Vapor deposition in basaltic stalactites, Kilauea, Hawaii

    Science.gov (United States)

    Baird, A. K.; Mohrig, D. C.; Welday, E. E.

    Basaltic stalacties suspended from the ceiling of a large lava tube at Kilauea, Hawaii, have totally enclosed vesicles whose walls are covered with euhedral FeTi oxide and silicate crystals. The walls of the vesicles and the exterior surfaces of stalactites are Fe and Ti enriched and Si depleted compared to common basalt. Minerals in vesicles have surface ornamentations on crystal faces which include alkali-enriched, aluminosilicate glass(?) hemispheres. No sulfide-, chloride-, fluoride-, phosphate- or carbonate-bearing minerals are present. Minerals in the stalactites must have formed by deposition from an iron oxide-rich vapor phase produced by the partial melting and vaporization of wall rocks in the tube.

  3. Hardness of basaltic glass-ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja

    2009-01-01

    The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved...... by varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

  4. Isotopic signature of Madeira basaltic magmatism

    International Nuclear Information System (INIS)

    Kogarko, L.N.; Karpenko, S.F.; Bibikova, E.V.; Mato, Zh.

    2000-01-01

    Chemical composition of the basalts of Madeira Island is studied. To assess the isotopic sources of magmatism the Pb-Sr, Sm-Nd, U-Th-Pb systems were investigated in a number of basalts. It is shown that the island's rocks are characterized by the mostly deplet sources in relation to Pb-Sr and Sm-Nd systems ( 87 Sr/ 86 Sr - 0.70282-0.70292, 143 Nd/ 144 Nd - 0.52303-0.51314). Isotopic composition of lead testifies that the magmatism reservoir is some enriched. It is concluded that the magmatism of Madeira Island is a new example of world ocean island's volcanism [ru

  5. Antifriction basalt-plastics based on polypropylene

    Science.gov (United States)

    Bashtannik, P. I.; Ovcharenko, V. G.

    1997-05-01

    A study is made of the dependence of the mechanical and friction-engineering properties of polypropylene reinforced with basalt fibers on the viscosity of the polymer matrix. It is established that the main factors that determine the mechanical properties of the plastics are the quality of impregnation of the fibers by the binder and the residual length of the reinforcing filler in the composite after extrusion and injection molding. The material that was developed has a low friction coefficient and low rate of wear within a relatively brood range of friction conditions. The basalt-plastics can be used in the rubbing parts of machines and mechanisms subjected to dry friction.

  6. Aboriginal oral traditions of Australian impact craters

    Science.gov (United States)

    Hamacher, Duane W.; Goldsmith, John

    2013-11-01

    In this paper we explore Aboriginal oral traditions that relate to Australian meteorite craters. Using the literature, first-hand ethnographic records and field trip data, we identify oral traditions and artworks associated with four impact sites: Gosses Bluff, Henbury, Liverpool and Wolfe Creek. Oral traditions describe impact origins for Gosses Bluff, Henbury and Wolfe Creek Craters, and non-impact origins for Liverpool Crater, with Henbury and Wolfe Creek stories having both impact and non-impact origins. Three impact sites that are believed to have been formed during human habitation of Australia -- Dalgaranga, Veevers, and Boxhole -- do not have associated oral traditions that are reported in the literature.

  7. Cratering statistics on asteroids: Methods and perspectives

    Science.gov (United States)

    Chapman, C.

    2014-07-01

    Crater size-frequency distributions (SFDs) on the surfaces of solid-surfaced bodies in the solar system have provided valuable insights about planetary surface processes and about impactor populations since the first spacecraft images were obtained in the 1960s. They can be used to determine relative age differences between surficial units, to obtain absolute model ages if the impactor flux and scaling laws are understood, to assess various endogenic planetary or asteroidal processes that degrade craters or resurface units, as well as assess changes in impactor populations across the solar system and/or with time. The first asteroid SFDs were measured from Galileo images of Gaspra and Ida (cf., Chapman 2002). Despite the superficial simplicity of these studies, they are fraught with many difficulties, including confusion by secondary and/or endogenic cratering and poorly understood aspects of varying target properties (including regoliths, ejecta blankets, and nearly-zero-g rubble piles), widely varying attributes of impactors, and a host of methodological problems including recognizability of degraded craters, which is affected by illumination angle and by the ''personal equations'' of analysts. Indeed, controlled studies (Robbins et al. 2014) demonstrate crater-density differences of a factor of two or more between experienced crater counters. These inherent difficulties have been especially apparent in divergent results for Vesta from different members of the Dawn Science Team (cf. Russell et al. 2013). Indeed, they have been exacerbated by misuse of a widely available tool (Craterstats: hrscview.fu- berlin.de/craterstats.html), which incorrectly computes error bars for proper interpretation of cumulative SFDs, resulting in derived model ages specified to three significant figures and interpretations of statistically insignificant kinks. They are further exacerbated, and for other small-body crater SFDs analyzed by the Berlin group, by stubbornly adopting

  8. Geologic implications of the Apollo 14 Fra Mauro breccias and comparison with ejecta from the Ries Crater, Germany

    Science.gov (United States)

    Chao, E.C.T.

    1973-01-01

    On the basis of petrographic and laboratory and active seismic data for the Fra Mauro breccias, and by comparison with the nature and distribution of the ejecta from the Ries crater, Germany, some tentative conclusions regarding the geologic significance of the Fra Mauro Formation on the moon can be drawn. The Fra Mauro Formation, as a whole, consists of unwcldcd, porous ejecta, slightly less porous than the regolith. It contains hand-specimen and larger size clasts of strongly annealed complex breccias, partly to slightly annealed breccias, basalts, and perhaps spherule-rich breccias. These clasts are embedded in a matrix of porous aggregate dominated by mineral and breccia fragments and probably largely free of undevitrified glass. All strongly annealed hand-specimen-size breccias are clasts in the Fra Mauro Formation. To account for the porous, unwelded state of the Fra Mauro Formation, the ejecta must have been deposited at a temperature below that required for welding and annealing. Large boulders probably compacted by the Cone crater event occur near the rim of the crater. They probably consist of a similar suite of fragments, but are probably less porous than the formation. The geochronologic clocks of fragments in the Fra Mauro Formation, with textures ranging from unannealed to strongly annealed, were not reset or strongly modified by the Imbrian event. Strongly annealed breccia clasts and basalt clasts are pre-Imbrian, and probably existed as ejecta mixed with basalt flows in the Imbrium Basin prior to the Imbrian event. The Imbrian event probably occurred between 3.90 or 3.88 and 3.65 b.y. ago.

  9. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    Directory of Open Access Journals (Sweden)

    URKHANOVA Larisa Alekseevna

    2014-08-01

    Full Text Available Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of basalt fiber.

  10. Investigation of Basalt Woven Fabrics for Military Applications

    Science.gov (United States)

    2011-11-01

    investigates the use of basalt fibers in a composite along with SC-15 epoxy resin for ballistic protection. Basalt fibers are not known as a ballistic...material but rather as a structural one. Even though basalt fibers are not expected to outperform some of the higher ballistic performing materials...such as the aramid and polyethylene fibers ; however, due to the lower manufacturing costs, basalt fibers are an interesting alternative. The objective

  11. Topography of the Martian Impact Crater Tooting

    Science.gov (United States)

    Mouginis-Mark, P. J.; Garbeil, H.; Boyce, J. M.

    2009-01-01

    Tooting crater is approx.29 km in diameter, is located at 23.4degN, 207.5degE, and is classified as a multi-layered ejecta crater [1]. Our mapping last year identified several challenges that can now be addressed with HiRISE and CTX images, but specifically the third dimension of units. To address the distribution of ponded sediments, lobate flows, and volatile-bearing units within the crater cavity, we have focused this year on creating digital elevation models (DEMs) for the crater and ejecta blanket from stereo CTX and HiRISE images. These DEMs have a spatial resolution of approx.50 m for CTX data, and 2 m for HiRISE data. Each DEM is referenced to all of the available individual MOLA data points within an image, which number approx.5,000 and 800 respectively for the two data types

  12. Fresh Impact Crater and Rays in Tharsis

    Science.gov (United States)

    2002-01-01

    The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission has included dozens of opportunities to point the spacecraft directly at features of interest so that pictures of things not seen during the earlier Mapping Mission can be obtained. The example shown here is a small meteorite impact crater in northern Tharsis near 17.2oN, 113.8oW. Viking Orbiter images from the late 1970's showed at this location what appeared to be a dark patch with dark rays emanating from a brighter center. The MOC team surmised that the dark rays may be indicating the location of afresh crater formed by impact sometime in the past few centuries (since dark ray are quickly covered by dust falling out of the martian atmosphere). All through MOC's Mapping Mission in 1999 and 2000, attempts were made to image the crater as predictions indicated that the spacecraft would pass over the site, but the crater was never seen. Finally, in June 2001, Extended Mission operations allowed the MOC team to point the spacecraft (and hence the camera, which is fixed to the spacecraft)directly at the center of the dark rays, where we expected to find the crater.The picture on the left (above, A) is a mosaic of three MOC high resolution images and one much lower-resolution Viking image. From left to right, the images used in the mosaic are: Viking 1 516A55, MOC E05-01904, MOCM21-00272, and MOC M08-03697. Image E05-01904 is the one taken in June 2001 by pointing the spacecraft. It captured the impact crater responsible for the rays. A close-up of the crater, which is only 130 meters (427 ft)across, is shown on the right (above, B). This crater is only one-tenth the size of the famous Meteor Crater in northern Arizona.The June 2001 MOC image reveals many surprises about this feature. For one, the crater is not located at the center of the bright area from which the dark rays radiate. The rays point to the center of this bright area, not the crater. Further, the dark material ejected from the

  13. Pressure grouting of fractured basalt flows

    International Nuclear Information System (INIS)

    Shaw, P.; Weidner, J.; Phillips, S.; Alexander, J.

    1996-04-01

    This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material

  14. Site identification presentation: Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    1979-11-01

    The final step in the site identification process for the Basalt Waste Isolation Project is described. The candidate sites are identified. The site identification methodology is presented. The general objectives which must be met in selecting the final site are listed. Considerations used in the screening process are also listed. Summary tables of the guidelines used are included

  15. Giant Plagioclase Basalts, eruption rate versus time

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging) 1461 1996 Oct 15 13:05:22

    I found the GPB lavas to be very interest- ing because in some ... by Venkatesan et al (1993) and thus in a way validates my approach. ... and age calculation of lavas from phenocrysts. Keywords. Deccan Trap; Giant Plagioclase Basalts; eruption duration. Proc. Indian Acad. Sci. (Earth Planet. Sci.), 111, No. 4, December ...

  16. Pressure grouting of fractured basalt flows

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, P.; Weidner, J.; Phillips, S.; Alexander, J.

    1996-04-01

    This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material.

  17. Petrography of basalts from the Carlsberg ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    Petrographic characteristics of basalts collected from a segment of the Carlsberg Ridge (lat. 3 degrees 35'N to 3 degrees 41'N; long. 64 degrees 05'E to 64 degrees 09'E) show typical pillow lava zonations with variable concentrations of plagioclase...

  18. Effects of Basalt Fibres on Mechanical Properties of Concrete

    Directory of Open Access Journals (Sweden)

    El-Gelani A. M.

    2018-01-01

    Full Text Available This paper presents the results of an experimental program carried out to investigate the effects of Basalt Fibre Reinforced Polymers (BFRP on some fundamental mechanical properties of concrete. Basalt fibres are formed by heating crushed basalt rocks and funnelling the molten basalt through a spinneret to form basalt filaments. This type of fibres have not been widely used till recently. Two commercially available chopped basalt fibres products with different aspect ratios were investigated, which are dry basalt (GeoTech Fibre and basalt pre-soaked in an epoxy resin (GeoTech Matrix .The experimental work included compression tests on 96 cylinders made of multiple batches of concrete with varying amounts of basalt fibre additives of the two mentioned types, along with control batches containing no fibres. Furthermore, flexural tests on 24 prisms were carries out to measure the modulus of rupture, in addition to 30 prisms for average residual strength test. Results of the research indicated that use of basalt fibres has insignificant effects on compressive strength of plain concrete, where the increase in strength did not exceed about 5%. On the other hand, results suggest that the use of basalt fibres may increase the compressive strength of concrete containing fly as up top 40%. The rupture strength was increased also by 8% to 28% depending on mix and fibre types and contents. Finally, there was no clear correlation between the average residual strength and ratios of basalt fibres mixed with the different concrete batches.

  19. Geochemical characteristics of the Jos-Plateau Basalts, North ...

    African Journals Online (AJOL)

    The Jos Plateau basalts, present Zr/Nb ratios (2.4-3.0) comparable to those of the alkali basalts of the lower Benue valley, and of the Cameroon volcanic line, suggesting that they were possibly derived from the same mantle source. Keywords: Jos Plateau, alkali basalt, mantle, partial melting, incompatible elements.

  20. Crater Mound Formation by Wind Erosion on Mars

    Science.gov (United States)

    Steele, L. J.; Kite, E. S.; Michaels, T. I.

    2018-01-01

    Most of Mars' ancient sedimentary rocks by volume are in wind-eroded sedimentary mounds within impact craters and canyons, but the connections between mound form and wind erosion are unclear. We perform mesoscale simulations of different crater and mound morphologies to understand the formation of sedimentary mounds. As crater depth increases, slope winds produce increased erosion near the base of the crater wall, forming mounds. Peak erosion rates occur when the crater depth is ˜2 km. Mound evolution depends on the size of the host crater. In smaller craters mounds preferentially erode at the top, becoming more squat, while in larger craters mounds become steeper sided. This agrees with observations where smaller craters tend to have proportionally shorter mounds and larger craters have mounds encircled by moats. If a large-scale sedimentary layer blankets a crater, then as the layer recedes across the crater it will erode more toward the edges of the crater, resulting in a crescent-shaped moat. When a 160 km diameter mound-hosting crater is subject to a prevailing wind, the surface wind stress is stronger on the leeward side than on the windward side. This results in the center of the mound appearing to "march upwind" over time and forming a "bat-wing" shape, as is observed for Mount Sharp in Gale crater.

  1. Petrology of basalts from Loihi Seamount, Hawaii

    Science.gov (United States)

    Hawkins, James; Melchior, John

    1983-12-01

    Loihi Seamount is the southeasternmost active volcano of the Emperor-Hawaii linear volcanic chain. It comprises a spectrum of basalt compositional varieties including basanite, alkali basalt, transitional basalt and tholeiite. Samples from four dredge collections made on Scripps Institution of Oceanography Benthic Expedition in October 1982 are tholeiite. The samples include highly vesicular, olivine-rich basalt and dense glass-rich pillow fragments containing olivine and augite phenocrysts. Both quartz-normative and olivine-normative tholeiites are present. Minor and trace element data indicate relatively high abundances of low partition coefficient elements (e.g., Ti, K, P. Rb, Ba, Zr) and suggest that the samples were derived by relatively small to moderate extent of partial melting, of an undepleted mantle source. Olivine composition, MgO, Cr and Ni abundances, and Mg/(Mg+Fe), are typical of moderately fractionated to relatively unfractionated "primary" magmas. The variations in chemistry between samples cannot be adequately explained by low-pressure fractional crystallization but can be satisfied by minor variations in extent of melting if a homogeneous source is postulated. Alternatively, a heterogeneous source with variable abundances of certain trace elements, or mixing of liquids, may have been involved. Data for 3He/ 4He, presented in a separate paper, implies a mantle plume origin for the helium composition of the Loihi samples. There is little variation in the helium isotope ratio for samples having different compositions and textures. The helium data are not distinctive enough to unequivocally separate the magma sources for the tholeiitic rocks from the other rock types such as Loihi alkalic basalts and the whole source region for Loihi may have a nearly uniform helium compositions even though other element abundances may be variable. Complex petrologic processes including variable melting, fractional crystallization and magma mixing may have blurred

  2. Vestas Pinaria Region: Original Basaltic Achondrite Material Derived from Mixing Upper and Lower Crust

    Science.gov (United States)

    Mcfadden, L. A.; Combe, Jean-Philippe; Ammannito, Eleonora; Frigeri, Alessandro; Stephan, Katrin; Longobardo, Andrea; Palomba, Ernesto; Tosi, Federico; Zambon, Francesca; Krohn, Katrin; hide

    2015-01-01

    Analysis of data from the Dawn mission shows that the Pinaria region of Vesta spanning a portion of the rim of the Rheasilvia basin is bright and anhydrous. Reflectance spectra, absorption band centers, and their variations, cover the range of pyroxenes from diogenite-rich to howardite and eucrite compositions, with no evidence of olivine in this region. By examining band centers and depths of the floor, walls and rims of six major craters in the region, we find a lane of diogenite-rich material next to howardite-eucrite material that does not follow the local topography. The source of this material is not clear and is probably ejecta from post-Rheasilvia impacts. Material of a howardite-eucrite composition originating from beyond the Rheasilvia basin is evident on the western edge of the region. Overall, the Pinaria region exposes the complete range of basaltic achondrite parent body material, with little evidence of contamination of non-basaltic achondrite material. With both high reflectance and low abundance of hydrated material, this region of Vesta may be considered the "Pinaria desert".

  3. A Study by Remote Sensing Methods of Volcanism at Craters of the Moon National Park, Idaho

    Science.gov (United States)

    Haberle, C. W.; Hughes, S. S.; Kobs-Nawotniak, S. E.; Lim, D. S. S.; Garry, B.; Sears, D. W. G.; Downs, M.; Busto, J.; Skok, J. R.; Elphic, R. C.; Kobayashi, L.; Heldmann, J. L.; Christensen, P. R.

    2014-12-01

    Craters of the Moon (COTM) National Park, on the eastern Snake River Plain, and its associated lava fields are currently a focus of the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team. COTM was selected for study owing to similarities with volcanic features observed on the Moon, Mars and Vesta. The COTM basaltic lava fields emanate from an 80 km long rift zone where at least eight eruptive episodes, occurring 15,000 to 2,000 BP, have created an expansive volcanic field covering an area of approximately 1,650 km2. This polygenetic volcanic field hosts a diverse collection of basaltic volcanic edifices such as phreatic explosion craters, eruptive fissures, cinder cones, spatter cones, shield volcanoes and expansive lava flows. Engineering challenges and high cost limit the number of robotic and human field investigations of planetary bodies and, due to these constraints, exhaustive remote sensing investigations of planetary surface properties are undertaken prior to field deployment. This creates an unavoidable dependence upon remote sensing, a critical difference between field investigations of planetary bodies and most terrestrial field investigations. Studies of this nature have utility in terrestrial investigations as they can help link spatially encompassing datasets and conserve field resources. We present preliminary results utilizing Earth orbital datasets to determine the efficacy of products derived from remotely sensed data when compared to geologic field observations. Multispectral imaging data (ASTER, AVIRIS, TIMS) collected at a range of spatial and spectral resolutions are paired with high resolution imagery from both orbit and unmanned aircraft systems. This enables the creation of derived products detailing morphology, compositional variation, mineralogy, relative age and vegetation. The surface morphology of flows within COTM differs from flow to flow and observations of these properties can aid in

  4. Pancam Peek into 'Victoria Crater' (Stereo)

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA08776 [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA08776 A drive of about 60 meters (about 200 feet) on the 943rd Martian day, or sol, of Opportunity's exploration of Mars' Meridiani Planum region (Sept. 18, 2006) brought the NASA rover to within about 50 meters (about 160 feet) of the rim of 'Victoria Crater.' This crater has been the mission's long-term destination for the past 21 Earth months. Opportunity reached a location from which the cameras on top of the rover's mast could begin to see into the interior of Victoria. This stereo anaglyph was made from frames taken on sol 943 by the panoramic camera (Pancam) to offer a three-dimensional view when seen through red-blue glasses. It shows the upper portion of interior crater walls facing toward Opportunity from up to about 850 meters (half a mile) away. The amount of vertical relief visible at the top of the interior walls from this angle is about 15 meters (about 50 feet). The exposures were taken through a Pancam filter selecting wavelengths centered on 750 nanometers. Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and therefore, potentially preserving several times the historical record.

  5. Decoding the Margins: What Can the Fractal Geometry of Basaltic Flow Margins Tell Us?

    Science.gov (United States)

    Schaefer, E. I.; Hamilton, C.; Neish, C.; Beard, S. P.; Bramson, A. M.; Sori, M.; Rader, E. L.

    2016-12-01

    Studying lava flows on other planetary bodies is essential to characterizing eruption styles and constraining the bodies' thermal evolution. Although planetary basaltic flows are common, many key features are not resolvable in orbital imagery. We are thus developing a technique to characterize basaltic flow type, sub-meter roughness, and sediment mantling from these data. We will present the results from upcoming fieldwork at Craters of the Moon National Monument and Preserve with FINESSE (August) and at Hawai'i Volcanoes National Park (September). We build on earlier work that showed that basaltic flow margins are approximately fractal [Bruno et al., 1992; Gaonac'h et al., 1992] and that their fractal dimensions (D) have distinct `a`ā and pāhoehoe ranges under simple conditions [Bruno et al., 1994]. Using a differential GPS rover, we have recently shown that the margin of Iceland's 2014 Holuhraun flow exhibits near-perfect (R2=0.9998) fractality for ≥24 km across dm to km scales [Schaefer et al., 2016]. This finding suggests that a fractal-based technique has significant potential to characterize flows at sub-resolution scales. We are simultaneously seeking to understand how margin fractality can be modified. A preliminary result for an `a'ā flow in Hawaii's Ka'ū Desert suggests that although aeolian mantling obscures the original flow margin, the apparent margin (i.e., sediment-lava interface) remains fractal [Schaefer et al., 2015]. Further, the apparent margin's D is likely significantly modified from that of the original margin. Other factors that we are exploring include erosion, transitional flow types, and topographic confinement. We will also rigorously test the intriguing possibility that margin D correlates with the sub-meter Hurst exponent H of the flow surface, a common metric of roughness scaling [e.g., Shepard et al., 2001]. This hypothesis is based on geometric arguments [Turcotte, 1997] and is qualitatively consistent with all results so far.

  6. Basalts of the Khodzhirbulak Suite and Assessment their Feasibility for Basalt Fiber (Surkhantau Mountains, Southwestern Shoots of the Hissar Ridge

    Directory of Open Access Journals (Sweden)

    N. M. Khakberdyev

    2017-06-01

    Full Text Available The results of preliminary assessment of basalt of the Khodzhirbulakskoy Suite of Surkhantau Mountains for the basalt fiber production are presented. According to petrographic study, the rocks are described as basalts of amygdaloidal structure. On the base of content of the amount of glassy form and nodular calcite, three groups of basalts were identified. The inverse relationship between the bulk content of the volcanic rock and the content of calcite: the greater volume of volcanic rocks, the less content of calcite, and vice versa. The basalt material demonstrates average pH module of 3.52.

  7. A Tale of Two Craters

    Science.gov (United States)

    2003-01-01

    [figure removed for brevity, see original site] In western Acidalia, two craters of similar size (a few km's) dramatically display the effects of geologic activity. The younger one on the left has been left relatively well preserved, retaining a sharp rim crest, a classic bowl shape, and a clearly defined ejecta blanket. The older one on the right likely has experienced a flood of lava that covered over the ejecta and filled in the bowl (note the breach in the rim). Its rim crest has been worn down by a multitude of subsequent impacts.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.Image information: VIS instrument. Latitude 35.9, Longitude 311.1 East (48.9 West). 19 meter/pixel resolution.

  8. The Global Contribution of Secondary Craters on the Icy Satellites

    Science.gov (United States)

    Hoogenboom, T.; Johnson, K. E.; Schenk, P.

    2014-12-01

    At present, surface ages of bodies in the Outer Solar System are determined only from crater size-frequency distributions (a method dependent on an understanding of the projectile populations responsible for impact craters in these planetary systems). To derive accurate ages using impact craters, the impactor population must be understood. Impact craters in the Outer Solar System can be primary, secondary or sesquinary. The contribution of secondary craters to the overall population has recently become a "topic of interest." Our objective is to better understand the contribution of dispersed secondary craters to the small crater populations, and ultimately that of small comets to the projectile flux on icy satellites in general. We measure the diameters of obvious secondary craters (determined by e.g. irregular crater shape, small size, clustering) formed by all primary craters on Ganymede for which we have sufficiently high resolution data to map secondary craters. Primary craters mapped range from approximately 40 km to 210 km. Image resolution ranges from 45 to 440 m/pixel. Bright terrain on Ganymede is our primary focus. These resurfaced terrains have relatively low crater densities and serve as a basis for characterizing secondary populations as a function of primary size on an icy body for the first time. Although focusing on Ganymede, we also investigate secondary crater size, frequency, distribution, and formation, as well as secondary crater chain formation on icy satellites throughout the Saturnian and Jovian systems principally Rhea. We compare our results to similar studies of secondary cratering on the Moon and Mercury. Using Galileo and Voyager data, we have identified approximately 3,400 secondary craters on Ganymede. In some cases, we measured crater density as a function of distance from a primary crater. Because of the limitations of the Galileo data, it is necessary to extrapolate from small data sets to the global population of secondary craters

  9. Cratering Equations for Zinc Orthotitanate Coated Aluminum

    Science.gov (United States)

    Hyde, James; Christiansen, Eric; Liou, Jer-Chyi; Ryan, Shannon

    2009-01-01

    The final STS-125 servicing mission (SM4) to the Hubble Space Telescope (HST) in May of 2009 saw the return of the 2nd Wide Field Planetary Camera (WFPC2) aboard the shuttle Discovery. This hardware had been in service on HST since it was installed during the SM1 mission in December of 1993 yielding one of the longest low Earth orbit exposure times (15.4 years) of any returned space hardware. The WFPC2 is equipped with a 0.8 x 2.2 m radiator for thermal control of the camera electronics (Figure 1). The space facing surface of the 4.1 mm thick aluminum radiator is coated with Z93 zinc orthotitanate thermal control paint with a nominal thickness of 0.1 0.2 mm. Post flight inspections of the radiator panel revealed hundreds of micrometeoroid/orbital debris (MMOD) impact craters ranging in size from less than 300 to nearly 1000 microns in diameter. The Z93 paint exhibited large spall areas around the larger impact sites (Figure 2) and the craters observed in the 6061-T651 aluminum had a different shape than those observed in uncoated aluminum. Typical hypervelocity impact craters in aluminum have raised lips around the impact site. The craters in the HST radiator panel had suppressed crater lips, and in some cases multiple craters were present instead of a single individual crater. Humes and Kinard observed similar behavior after the WFPC1 post flight inspection and assumed the Z93 coating was acting like a bumper in a Whipple shield. Similar paint behavior (spall) was also observed by Bland2 during post flight inspection of the International Space Station (ISS) S-Band Antenna Structural Assembly (SASA) in 2008. The SASA, with similar Z93 coated aluminum, was inspected after nearly 4 years of exposure on the ISS. The multi-crater phenomena could be a function of the density, composition, or impact obliquity angle of the impacting particle. For instance, a micrometeoroid particle consisting of loosely bound grains of material could be responsible for creating the

  10. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  11. Technical program plan, Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    1979-12-01

    The Basalt Waste Isolation Project (BWIP) program as administered by the DOE's Richland Operations Office and Rockwell Hanford Operations is described. The objectives, scope and scientific technologies are discussed. The work breakdown structure of the project includes: project management and support, systems integration, geosciences, hydrology, engineered barriers, test facility design and construction, engineering testing, repository studies, and schedules. The budget of the program including operating and capital cost control is also included

  12. Gamma radiolysis effects on basalt groundwater

    International Nuclear Information System (INIS)

    Gray, W.J.

    1983-10-01

    Gamma radiolysis of basalt groundwater containing 700 ppM methane produces a milky liquid that is a suspension of fine particles of a high molecular weight hydrocarbon somewhat like polyethylene. The ability of these polymers to chelate with, or otherwise sorb, metal ions from aqueous solution was measured using Cu +2 as a representative cation. Values in the range 0.3 to 0.8 millimoles of Cu per liter of solution were found. 5 references, 2 figures, 2 tables

  13. Optimizing laser crater enhanced Raman scattering spectroscopy

    Science.gov (United States)

    Lednev, V. N.; Sdvizhenskii, P. A.; Grishin, M. Ya.; Fedorov, A. N.; Khokhlova, O. V.; Oshurko, V. B.; Pershin, S. M.

    2018-05-01

    The laser crater enhanced Raman scattering (LCERS) spectroscopy technique has been systematically studied for chosen sampling strategy and influence of powder material properties on spectra intensity enhancement. The same nanosecond pulsed solid state Nd:YAG laser (532 nm, 10 ns, 0.1-1.5 mJ/pulse) was used for laser crater production and Raman scattering experiments for L-aspartic acid powder. Increased sampling area inside crater cavity is the key factor for Raman signal improvement for the LCERS technique, thus Raman signal enhancement was studied as a function of numerous experimental parameters including lens-to-sample distance, wavelength (532 and 1064 nm) and laser pulse energy utilized for crater production. Combining laser pulses of 1064 and 532 nm wavelengths for crater ablation was shown to be an effective way for additional LCERS signal improvement. Powder material properties (particle size distribution, powder compactness) were demonstrated to affect LCERS measurements with better results achieved for smaller particles and lower compactness.

  14. Iron isotopic systematics of oceanic basalts

    Science.gov (United States)

    Teng, Fang-Zhen; Dauphas, Nicolas; Huang, Shichun; Marty, Bernard

    2013-04-01

    The iron isotopic compositions of 93 well-characterized basalts from geochemically and geologically diverse mid-ocean ridge segments, oceanic islands and back arc basins were measured. Forty-three MORBs have homogeneous Fe isotopic composition, with δ56Fe ranging from +0.07‰ to +0.14‰ and an average of +0.105 ± 0.006‰ (2SD/√n, n = 43, MSWD = 1.9). Three back arc basin basalts have similar δ56Fe to MORBs. By contrast, OIBs are slightly heterogeneous with δ56Fe ranging from +0.05‰ to +0.14‰ in samples from Koolau and Loihi, Hawaii, and from +0.09‰ to +0.18‰ in samples from the Society Islands and Cook-Austral chain, French Polynesia. Overall, oceanic basalts are isotopically heavier than mantle peridotite and pyroxenite xenoliths, reflecting Fe isotope fractionation during partial melting of the mantle. Iron isotopic variations in OIBs mainly reflect Fe isotope fractionation during fractional crystallization of olivine and pyroxene, enhanced by source heterogeneity in Koolau samples.

  15. AEGIS methodology demonstration: case example in basalt

    International Nuclear Information System (INIS)

    Dove, F.H.

    1982-01-01

    The AEGIS technology has been successfully demonstrated. For the same data, similar unpublished results have been obtained by RHO and INTERA Environmental Consultants, Inc. for contaminant transport. In addition to establishing the utility of computer codes and assessment methodology, the AEGIS technology demonstration in basalt has also produced some practical guidance for future field data gathering programs. The results of this basalt demonstration indicate that the geohydrologic systems separating the nuclear waste from the natural biosphere discharge site mitigate the consequences of the postulated fault intersection event. This analysis suggests that the basalt system satisfies the 1000- and 10,000-yr proposed standards for release to the accessible environment (limited release of 129 I and 14 C). The reader should be cautioned, however, that the results are valid only for one particular set of parameters and one postulated release scenario. A complete sensitivity analysis must be performed to evaluate the range of effects that might be observed under different release conditions and for the different range in parameters

  16. Hydrologic modeling of the Columbia Plateau basalts

    International Nuclear Information System (INIS)

    Dove, F.H.; Cole, C.R.; Bond, F.W.; Zimmerman, D.A.

    1982-09-01

    The Office of Nuclear Waste Isolation (ONWI) directed the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program to conduct a technology demonstration of current performance assessment techniques for the Department of Energy (DOE) as applied to a nuclear waste repository in the Columbia Plateau Basalts. Hypothetical repository coordinates were selected for an actual geographical setting on the Hanford Reservation in the state of Washington. Published hydrologic and geologic data used in the analyses were gathered in 1979 or earlier. The hydrologic simulation was divided into three major parts: (1) aquifer recharge calculations, (2) a regional hydrologic model, and (3) a local hydrologic model of the Pasco Basin. The presentation discusses the regional model. An estimate of the amount of water transmitted through the groundwater system was required to bound the transmissivity values and to estimate the transmissivity distributions for the deeper basalts. The multiple layer two-dimensional Variable Thickness Transient (VTT) code was selected as appropriate for the amount of data available and for the conditions existing in the regional systems. This model uses a finite difference formulation to represent the partial differential flow equation. The regional study area as defined for the VTT model was divided into 55 by 55 square pattern with each grid 5 kilometers on a side. The regional system was modeled as a held potential surface layer and two underlying basalt layers. The regional model established the boundary conditions for the hydrologic model the Pasco Basin

  17. Lunar floor-fractured craters as magmatic intrusions: Geometry, modes of emplacement, associated tectonic and volcanic features, and implications for gravity anomalies

    Science.gov (United States)

    Jozwiak, Lauren M.; Head, James W.; Wilson, Lionel

    2015-03-01

    , the intrusion concentrates bending primarily at the periphery, resulting in a flat, tabular intrusion. We predict that this process will result in concentric fractures over the region of greatest bending. This location is close to the crater wall in large, flat-floored craters, as observed in the crater Humboldt, and interior to the crater over the domed floor in smaller craters, as observed in the crater Vitello. A variety of volcanic features are predicted to be associated with the solidification and degassing of the intrusion; these include: (1) surface lava flows associated with concentric fractures (e.g., in the crater Humboldt); (2) vents with no associated pyroclastic material, from the deflation of under-pressurized magmatic foam (e.g., the crater Damoiseau); and (3) vents with associated pyroclastic deposits from vulcanian eruptions of highly pressurized magmatic foam (e.g., the crater Alphonsus). The intrusion of basaltic magma beneath the crater is predicted to contribute a positive component to the Bouguer gravity anomaly; we assess the predicted Bouguer anomalies associated with FFCs and outline a process for their future interpretation. We conclude that our proposed mechanism serves as a viable formation process for FFCs and accurately predicts numerous morphologic, morphometric, and geophysical features associated with FFCs. These predictions can be further tested using GRAIL (Gravity Recovery and Interior Laboratory) data.

  18. Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

    Science.gov (United States)

    Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.; hide

    2015-01-01

    The Mars Science Laboratory (MSL) rover Curiosity recently completed its fourth drill sampling of sediments on Mars. The Confidence Hills (CH) sample was drilled from a rock located in the Pahrump Hills region at the base of Mt. Sharp in Gale Crater. The CheMin X-ray diffractometer completed five nights of analysis on the sample, more than previously executed for a drill sample, and the data have been analyzed using Rietveld refinement and full-pattern fitting to determine quantitative mineralogy. Confidence Hills mineralogy has several important characteristics: 1) abundant hematite and lesser magnetite; 2) a 10 angstrom phyllosilicate; 3) multiple feldspars including plagioclase and alkali feldspar; 4) mafic silicates including forsterite, orthopyroxene, and two types of clinopyroxene (Ca-rich and Ca-poor), consistent with a basaltic source; and 5) minor contributions from sulfur-bearing species including jarosite.

  19. Experimental Alteration of Basalt to Support Interpretation of Remote Sensing and In Situ Meausrements from Mars

    Science.gov (United States)

    Bell, M. S.

    2014-01-01

    Major occurrences of hydrous alteration minerals on Mars have been found in Noachian impact craters formed in basaltic targets and detected using visible/near infrared (VNIR) spectroscopy. Until recently phyllosilicates were detected only in craters in the southern hemisphere [1, 2]. However, it has been reported that at least nine craters in the northern plains apparently excavated thick layers of lava and sediment to expose phyllosilicates [3] as well. The MER (Mars Exploration Rovers) rovers previously reported results of in situ measurement indicating the presence of alteration minerals on Mars [4,5] and it was recently reported that the Mars Curiosity rover has detected alteration phases in situ at Yellowknife Bay in Gale crater as well [6,7]. An important discovery for Mars geochronology is that the Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument on Curiosity detected phyllosilicates indicating that phyllosilicate formation on Mars extended beyond the Noachian Epoch [8]. These discoveries indicate that Mars was globally altered by water in the past but does not constrain formation conditions for alteration phase occurrences, which have important implications for the evolution of the surface and the biological potential on Mars. Understanding the alteration assemblages produced by a range of conditions is vital for the interpretation of phyllosilicate spectral signatures as well as in situ measurements and to decipher the environment and evolution of early Mars. The martian surface has been intensely altered by meteorite impacts whose effects include brecciation and melting of target materials as well as the initiation of hydrothermal circulation in a hydrous target [9,10,11,12]. Impact effects may facilitate aqueous alteration of a basaltic target because the rate of silicate dissolution is a function of the degree of crystallinity, surface area, and temperature. The resultant alteration mineralogies from shocked basaltic target material

  20. Health improvement of domestic hot tap water supply Gusev, Kaliningrad Region, Russia. Make-up water tank project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard, Joergen

    1998-07-01

    This report describes the project `Health Improvement of Domestic Hot Tap Water Supply, Gusev, Kaliningrad, Russia`, which was carried out in the autumn of 1996 and financed by the Danish Environmental Protection Agency, the Danish Energy Agency and Gusev Municipality. The project proposal and application outlined the following objectives: Erection of system so that hot tap water, which is tapped directly from the district heating system, obtains an acceptable quality in health terms; Complete training and education, so that the plant can be operated and maintained by the power station`s staff and rehabilitation projects within supply of domestic water and district heating can be promoted to the greatest possible extent; Systems for heat treatment of make-up water were implemented in less than three months; The project was carried out in close Danish-Russian co-operation from the beginning of engineering to the commissioning and resulted in transfer and demonstration of know-how and technology; Information was recorded on the existing domestic water and heat supply systems as well as on the treatment of sewage, and recommendations for rehabilitation projects were made. Previously, when the temperature in the district heating system was relatively high, a heat treatment apparently took place in the district heating system. However, due to the current poor economic situation there are no means with which to buy the fuel quantities necessary to maintain the previously normal district heating temperature. In the new concept the cold make-up water is heated to >80 deg. C as required by the health authorities before it is led to the district heating return system and subsequently heated to the actual supply temperature of 50-60 deg. C. The energy consumption in the two concepts is approximately the same. A 1,000 m{sup 3} tank with heating coils was erected between the make-up water system and the district heating system. The tank should equalise the daily capacity

  1. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    International Nuclear Information System (INIS)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-06-01

    A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10 8 kg, with a corresponding kinetic energy of 1.88 x 10 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references

  2. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    International Nuclear Information System (INIS)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-04-01

    A computational approach used for subsurface explosion cratering has been extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for our first computer simulation because it was the most thoroughly studied. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Shoemaker estimates that the impact occurred about 20,000 to 30,000 years ago [Roddy (1977)]. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s. meteorite mass of 1.57E + 08 kg, with a corresponding kinetic energy of 1.88E + 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation a Tillotson equation-of-state description for iron and limestone was used with no shear strength. A color movie based on this calculation was produced using computer-generated graphics. Results obtained for this preliminary calculation of the formation of Meteor Crater, Arizona, are in good agreement with Meteor Crater Measurements

  3. Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.

    1978-06-01

    A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10/sup 8/ kg, with a corresponding kinetic energy of 1.88 x 10/sup 16/ J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references.

  4. Experimental investigation of crater growth dynamics

    Science.gov (United States)

    Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.; Holsapple, K. A.

    1985-01-01

    This work is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large-body impacts onto planetary surfaces. The centrifuge technique is used to provide experimental data for actual target materials of interest. With both power and gas guns mounted on the rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large-scale impacts. The development of the centrifuge technique has been poineered by the present investigators and is documented by numerous publications, the most recent of which are listed below. Understanding the dependence of crater size upon gravity has been shown to be key to the complete determination of the dynamic and kinematic behavior of crater formation as well as ejecta phenomena. Three unique time regimes in the formation of an impact crater have been identified.

  5. Crater monitoring through social media observations

    Science.gov (United States)

    Gialampoukidis, I.; Vrochidis, S.; Kompatsiaris, I.

    2017-09-01

    We have collected more than one lunar image per two days from social media observations. Each one of the collected images has been clustered into two main groups of lunar images and an additional cluster is provided (noise) with pictures that have not been assigned to any cluster. The proposed lunar image clustering process provides two classes of lunar pictures, at different zoom levels; the first showing a clear view of craters grouped into one cluster and the second demonstrating a complete view of the Moon at various phases that are correlated with the crawling date. The clustering stage is unsupervised, so new topics can be detected on-the-fly. We have provided additional sources of planetary images using crowdsourcing information, which is associated with metadata such as time, text, location, links to other users and other related posts. This content has crater information that can be fused with other planetary data to enhance crater monitoring.

  6. Physics of soft impact and cratering

    CERN Document Server

    Katsuragi, Hiroaki

    2016-01-01

    This book focuses on the impact dynamics and cratering of soft matter to describe its importance, difficulty, and wide applicability to planetary-related problems. A comprehensive introduction to the dimensional analysis and constitutive laws that are necessary to discuss impact mechanics and cratering is first provided. Then, particular coverage is given to the impact of granular matter, which is one of the most crucial constituents for geophysics. While granular matter shows both solid-like and fluid-like behaviors, neither solid nor fluid dynamics is sufficient to fully understand the physics of granular matter. In order to reveal its fundamental properties, extensive impact tests have been carried out recently. The author reveals the findings of these recent studies as well as what remains unsolved in terms of impact dynamics. Impact crater morphology with various soft matter impacts also is discussed intensively. Various experimental and observational results up to the recent Itokawa asteroid’s terrain...

  7. A concept of row crater enhancement

    International Nuclear Information System (INIS)

    Redpath, B.B.

    1970-01-01

    Linear craters formed by the simultaneous detonation of a row of buried explosives will probably have a wider application than single charges in the explosive excavation of engineering structures. Most cratering experience to date has been with single charges, and an analytical procedure for the design of a row of charges to excavate a crater with a specified configuration has been lacking. There are no digital computer codes having direct application to a row of charges as there are for single charges. This paper derives a simple relationship which can be used to design row charges with some assurance of achieving the desired result and with considerable flexibility in the choice of explosive yield of the individual charges

  8. Goat paddock cryptoexplosion crater, Western Australia

    Science.gov (United States)

    Harms, J.E.; Milton, D.J.; Ferguson, J.; Gilbert, D.J.; Harris, W.K.; Goleby, B.

    1980-01-01

    Goat Paddock, a crater slightly over 5 km in diameter (18??20??? S, 126??40???E), lies at the north edge of the King Leopold Range/Mueller Range junction in the Kimberley district, Western Australia (Fig. 1). It was noted as a geological anomaly in 1964 during regional mapping by the Bureau of Mineral Resources, Geology and Geophysics and the Geological Survey of Western Australia. The possibility of its being a meteorite impact crater has been discussed1, although this suggestion was subsequently ignored2. Two holes were drilled by a mining corporation in 1972 to test whether kimberlite underlay the structure. Here we report the findings of five days of reconnaissance in August 1979 which established that Goat Paddock is a cryptoexplosion crater containing shocked rocks and an unusually well exposed set of structural features. ?? 1980 Nature Publishing Group.

  9. El'gygytgyn impact crater, Chukotka, Arctic Russia: Impact cratering aspects of the 2009 ICDP drilling project

    Science.gov (United States)

    Koeberl, Christian; Pittarello, Lidia; Reimold, Wolf Uwe; Raschke, Ulli; Brigham-Grette, Julie; Melles, Martin; Minyuk, Pavel; Spray, John

    2013-01-01

    The El'gygytgyn impact structure in Chukutka, Arctic Russia, is the only impact crater currently known on Earth that was formed in mostly acid volcanic rocks (mainly of rhyolitic, with some andesitic and dacitic, compositions). In addition, because of its depth, it has provided an excellent sediment trap that records paleoclimatic information for the 3.6 Myr since its formation. For these two main reasons, because of the importance for impact and paleoclimate research, El'gygytgyn was the subject of an International Continental Scientific Drilling Program (ICDP) drilling project in 2009. During this project, which, due to its logistical and financial challenges, took almost a decade to come to fruition, a total of 642.3 m of drill core was recovered at two sites, from four holes. The obtained material included sedimentary and impactite rocks. In terms of impactites, which were recovered from 316.08 to 517.30 m depth below lake bottom (mblb), three main parts of that core segment were identified: from 316 to 390 mblb polymict lithic impact breccia, mostly suevite, with volcanic and impact melt clasts that locally contain shocked minerals, in a fine-grained clastic matrix; from 385 to 423 mblb, a brecciated sequence of volcanic rocks including both felsic and mafic (basalt) members; and from 423 to 517 mblb, a greenish rhyodacitic ignimbrite (mostly monomict breccia). The uppermost impactite (316–328 mblb) contains lacustrine sediment mixed with impact-affected components. Over the whole length of the impactite core, the abundance of shock features decreases rapidly from the top to the bottom of the studied core section. The distinction between original volcanic melt fragments and those that formed later as the result of the impact event posed major problems in the study of these rocks. The sequence that contains fairly unambiguous evidence of impact melt (which is not very abundant anyway, usually less than a few volume%) is only about 75 m thick. The reason for

  10. Lomonosov Crater, Day and Night

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 16 June 2004 This pair of images shows part of Lomonosov Crater. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude 64.9, Longitude 350.7 East (9.3 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project

  11. Optimizing laser crater enhanced Raman spectroscopy.

    Science.gov (United States)

    Lednev, V N; Sdvizhenskii, P A; Grishin, M Ya; Filichkina, V A; Shchegolikhin, A N; Pershin, S M

    2018-03-20

    Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset. The influence of the experiment parameters on Raman signal enhancement was studied for different powder materials. Maximum Raman signal enhancement reached 11 fold for loose powders but decreased twice for pressed tablets. Raman signal enhancement was demonstrated for several diverse powder materials like gypsum or ammonium nitrate with better results achieved for the samples tending to give narrow and deep craters upon the laser ablation stage. Alternative ways of cavity production (steel needle tapping and hole drilling) were compared with the laser cratering technique in terms of Raman signal enhancement. Drilling was found to give the poorest enhancement of the Raman signal, while both laser ablation and steel needle tapping provided comparable results. Here, we have demonstrated for the first time, to the best of our knowledge, that a Raman signal can be enhanced 10 fold with the aid of simple cavity production by steel needle tapping in rough highly reflective materials. Though laser crater enhancement Raman spectroscopy requires an additional pulsed laser, this technique is more appropriate for automatization compared to the needle tapping approach.

  12. Making rhyolite in a basalt crucible

    Science.gov (United States)

    Eichelberger, John

    2016-04-01

    Iceland has long attracted the attention of those concerned with the origin of rhyolitic magmas and indeed of granitic continental crust, because it presents no alternative for such magmas other than deriving them from a basaltic source. Hydrothermally altered basalt has been identified as the progenitor. The fact that rhyolite erupts as pure liquid requires a process of melt-crustal separation that is highly efficient despite the high viscosity of rhyolite melt. Volcanoes in Iceland are foci of basaltic magma injection along the divergent plate boundary. Repeated injection produces remelting, digestion, and sometimes expulsion or lateral withdrawal of material resulting in a caldera, a "crucible" holding down-dropped and interlayered lava flows, tephras, and injected sills. Once melting of this charge begins, a great deal of heat is absorbed in the phase change. Just 1% change in crystallinity per degree gives a melt-present body an effective heat capacity >5 times the subsolidus case. Temperature is thus buffered at the solidus and melt composition at rhyolite. Basalt inputs are episodic ("fires") so likely the resulting generation of rhyolite by melting is too. If frequent enough to offset cooling between events, rhyolite melt extractions will accumulate as a rhyolite magma reservoir rather than as discrete crystallized sills. Evidently, such magma bodies can survive multiple firings without themselves erupting, as the 1875 eruption of Askja Caldera of 0.3 km3 of rhyolite equilibrated at 2-km depth without previous leakage over a ten-millennium period and the surprise discovery of rhyolite magma at 2-km depth in Krafla suggest. Water is required for melting; otherwise melting cannot begin at a temperature lower than that of the heat source. Because the solubility of water in melt is pressure-dependent and almost zero at surface pressure, there must be a minimum depth at which basalt-induced melting can occur and a rhyolite reservoir sustained. In practice, the

  13. Laboratory and Field Investigations of Small Crater Repair Technologies

    National Research Council Canada - National Science Library

    Priddy, Lucy P; Tingle, Jeb S; McCaffrey, Timothy J; Rollings, Ray S

    2007-01-01

    .... This airfield damage repair (ADR) investigation consisted of laboratory testing of selected crater fill and capping materials, as well as full-scale field testing of small crater repairs to evaluate field mixing methods, installation...

  14. Crater ejecta scaling laws: fundamental forms based on dimensional analysis

    International Nuclear Information System (INIS)

    Housen, K.R.; Schmidt, R.M.; Holsapple, K.A.

    1983-01-01

    A model of crater ejecta is constructed using dimensional analysis and a recently developed theory of energy and momentum coupling in cratering events. General relations are derived that provide a rationale for scaling laboratory measurements of ejecta to larger events. Specific expressions are presented for ejection velocities and ejecta blanket profiles in two limiting regimes of crater formation: the so-called gravity and strength regimes. In the gravity regime, ejectra velocities at geometrically similar launch points within craters vary as the square root of the product of crater radius and gravity. This relation implies geometric similarity of ejecta blankets. That is, the thickness of an ejecta blanket as a function of distance from the crater center is the same for all sizes of craters if the thickness and range are expressed in terms of crater radii. In the strength regime, ejecta velocities are independent of crater size. Consequently, ejecta blankets are not geometrically similar in this regime. For points away from the crater rim the expressions for ejecta velocities and thickness take the form of power laws. The exponents in these power laws are functions of an exponent, α, that appears in crater radius scaling relations. Thus experimental studies of the dependence of crater radius on impact conditions determine scaling relations for ejecta. Predicted ejection velocities and ejecta-blanket profiles, based on measured values of α, are compared to existing measurements of velocities and debris profiles

  15. Coesite from Wabar crater, near Al Hadida, Arabia

    Science.gov (United States)

    Chao, E.C.T.; Fahey, J.J.; Littler, J.

    1961-01-01

    The third natural occurrence of coesite, the high pressure polymorph of silica, is found at the Wabar meteorite crater, Arabia. The Wabar crater is about 300 feet in diameter and about 40 feet deep. It is the smallest of three craters where coesite has been found.

  16. Cratering on Small Bodies: Lessons from Eros

    Science.gov (United States)

    Chapman, C. R.

    2003-01-01

    Cratering and regolith processes on small bodies happen continuously as interplanetary debris rains down on asteroids, comets, and planetary satellites. Butthey are very poorly observed and not well understood. On the one hand, we have laboratory experimentation at small scales and we have examination of large impact craters (e.g. Meteor Crater on Earth and imaging of abundant craters on terrestrial planets and outer planet moons). Understanding cratering on bodies of intermediate scales, tens of meters to hundreds of km in size, involves either extrapolation from our understanding of cratering phenomena at very different scales or reliance on very preliminary, incomplete examination of the observational data we now have for a few small bodies. I review the latter information here. It has been generally understood that the role of gravity is greatly diminished for smaller bodies, so a lot of cratering phenomena studied for larger bodies is less applicable. But it would be a mistake to imagine that laboratory experiments on gravitationless rocks (usually at 1 g) are directly applicable, except perhaps to those monolithic Near Earth Asteroids (NEAs) some tens of meters in size that spin very rapidly and can be assumed to be "large bare rocks" with "negative gravity". Whereas it had once been assumed that asteroids smaller than some tens of km diameter would retain little regolith, it is increasingly apparent that regolith and megoregolith processes extend down to bodies only hundreds of meters in size, perhaps smaller. Yet these processes are very different from those that pertain to the Moon, which is our chief prototype of regolith processes. The NEAR Shoemaker spacecraft's studies of Eros provide the best evidence to date about small-body cratering processes, as well as a warning that our theoretical understanding requires anchoring by direct observations. Eros: "Ponds", Paucity of Small Craters, and Other Mysteries. Although Eros is currently largely detached

  17. Terrestrial Analogs for Clay Minerals at Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    Treiman, Allan H; Morris, Richard V.; Bristow, Thomas; Ming, Douglas W.; Achillies, Cherie; Bish, David L.; Blake, David; Vaniman, David; Chipera, Steve

    2013-01-01

    Sediments of the Sheepbed unit, Gale Crater, were analyzed by the CheMin X-ray diffraction instrument on the Curiosity Rover. The sediments consist of typical basalt minerals (Fe-forsterite, augite, pigeonite, plagioclase), as well as Fe oxide/hydroxides, Fesulfides, amorphous material, and a phyllosilicate. The phyllosilicate has a broad 001 peak at approx 1.0 nm, consistent with a poorly ordered smectite. However, in the absence of diagnostic tests possible on Earth, its identity is not clear. The position of the 06L diffraction band is generally used to distinguish dioctahedral from trioctahedral smectite, but it is beyond CheMin's range of 2 Theta. The measured position of the 02L diffraction band (approx 22.5deg 2 Theta by CheMin), implies that the smectite is trioctahedral. The exact position and shape of the 02L band is determined by the cations in the 'M' sites of the smectite; to constrain those cations, we sought analogs among terrestrial smectites, emphasizing those developed from basaltic precursors. A potential analog for the Sheepbed smectite is 'griffithite,' a variety of trioctahedral smectite in altered basalt of the Topanga formation, Griffith Park, Los Angeles. 'Griffithite' has an 02L diffraction band that is close in position and shape to that of the Sheepbed smectite, although 'griffithite' has a very sharp 001 peak, indicating a high degree of layer ordering not seen in the Sheepbed smectite. A typical chemical formula for 'griffithite,' determined by electron microprobe, is (Ca0.59 Na0.03) (Mg4.28 Fe1.83) (Si6.64 Al1.36) O20 (OH)4, normalized to Si+Al=8. This formula is consistent with a fully trioctahedral Fe-Mg smectite with Ca and Na as interlayer cations. In the Topanga basalt, four types of 'griffithite' are present: fine-grained, filling cracks and vesicles; coarse-grained, filling vesicles; coarse-grained, replacing olivine phenocrysts; and coarse-grained, replacing glassy mesostasis. The fine-grained 'griffithite' formed first, and

  18. Is the Linné impact crater morphology influenced by the rheological layering on the Moon's surface? Insights from numerical modeling

    Science.gov (United States)

    Martellato, Elena; Vivaldi, Valerio; Massironi, Matteo; Cremonese, Gabriele; Marzari, Francesco; Ninfo, Andrea; Haruyama, Junichi

    2017-07-01

    Linné is a simple crater, with a diameter of 2.23 km and a depth of 0.52 km, located in northwestern Mare Serenitatis. Recent high-resolution data acquired by the Lunar Reconnaissance Orbiter Camera revealed that the shape of this impact structure is best described by an inverted truncated-cone. We perform morphometric measurements, including slope and profile curvature, on the Digital Terrain Model of Linné, finding the possible presence of three subtle topographic steps, at the elevation of +20, -100, and -200 m relative to the target surface. The kink at -100 m might be related to the interface between two different rheological layers. Using the iSALE shock physics code, we numerically model the formation of Linné crater to derive hints on the possible impact conditions and target physical properties. In the initial setup, we adopt a basaltic projectile impacting the Moon with a speed of 18 km s-1. For the local surface, we consider either one or two layers, in order to test the influence of material properties or composite rheologies on the final crater morphology. The one-layer model shows that the largest variations in the crater shape take place when either the cohesion or the friction coefficient is varied. In particular, a cohesion of 10 kPa marks the threshold between conical- and parabolic-shaped craters. The two-layer model shows that the interface between the two layers would be exposed at the observed depth of 100 m when an intermediate value ( 200 m) for the upper fractured layer is set. We have also found that the truncated-cone morphology of Linné might originate from an incomplete collapse of the crater wall, as the breccia lens remains clustered along the crater walls, while the high-albedo deposit on the crater floor can be interpreted as a very shallow lens of fallout breccia. The modeling analysis allows us to derive important clues on the impactor size (under the assumption of a vertical impact and collision velocity equal to the mean

  19. Magnetostratigraphy of the Grande Ronde Basalt Pasco Basin, Washington

    International Nuclear Information System (INIS)

    Packer, D.R.; Petty, M.H.

    1979-01-01

    The paleomagnetic measurements of samples from the holes sampled have shown that there are four magnetic correlation lines, between adjacent flows in holes that have distinctly different mean stratigraphic inclinations, and two magnetic polarity boundaries that can be used for magnetic correlation in the Grande Ronde Basalt in the Pasco Basin. The results of paleomagnetic measurements of samples from the Wanapum Basalt and Saddle Mountains Basalt indicate that the potential for magnetostratigraphic correlation in these sequences is also good

  20. Increased corrosion resistance of basalt reinforced cement compositions with nanosilica

    OpenAIRE

    URKHANOVA Larisa Alekseevna; LKHASARANOV Solbon Aleksandrovich; ROZINA Victoria Yevgenievna; BUYANTUEV Sergey Lubsanovich; BARDAKHANOV Sergey Prokopievich

    2014-01-01

    Disperse fiber reinforcement is used to improve deformation and shrinkage characteristics, flexural strength of concrete. Basalt roving and thin staple fiber are often used as mineral fibers. The paper considers the problems of using thin basalt fiber produced by centrifugal-blow method. Evaluation of the corrosion resistance of basalt fiber as part of the cement matrix was performed. Nanodispersed silica produced by electron beam accelerator was used to increase corrosion resistance of ba...

  1. Crystallisation condition of the Quaternary basanites of volcanic centre Black Rock, monogenetic field Lunar Crater

    Science.gov (United States)

    Turova, Mariia; Plechov, Pavel; Scherbakov, Vasily; Larin, Nikolay

    2017-04-01

    The Lunar Crater volcanic field is located in a tension zone Basin and Range Province (USA). This tension is connected with dives oceanic plate under the continental plate [1]. Lunar Crater consists of flows basalt, basanite, trachybasalt has a different age [2]. In this work we investigate the youngest rock - basanite. The basanite is highly crystalline consisting of about megacrysts (3-10 cm) 30-60 wt% phenocrysts ( 800-1500 µm) and microphenocrysts (100-800 µm) and 40-60% microlites (Mathematical, Physical and Engineering Sciences. - 1981. - T. 300. - №. 1454. - C. 407-434. 2. Wood, X., and Keinle, Y., 1990, Volcanoes of North America: Cambridge,United Kingdom, Cambridge University Press, 354 p. 3. Nimis P. Clinopyroxene geobarometry of magmatic rocks. Part 2. Structural geobarometers for basic to acid, tholeiitic and mildly alkaline magmatic systems //Contributions to Mineralogy and Petrology. - 1999. - T. 135. - №. 1. - C. 62-74. 4. Ballhaus C., Berry R. F., Green D. H. High pressure experimental calibration of the olivine-orthopyroxene-spinel oxygen geobarometer: implications for the oxidation state of the upper mantle //Contributions to Mineralogy and Petrology. - 1991. - T. 107. - №. 1. - C. 27-40.

  2. Morphology and chemistry of projectile residue in small experimental impact craters

    Science.gov (United States)

    Horz, F.; Fechtig, H.; Janicke, J.; Schneider, E.

    1983-01-01

    Small-scale impact craters (5-7 mm in diameter) were produced with a light gas gun in high purity Au and Cu targets using soda lime glass (SL) and man-made basalt glass (BG) as projectiles. Maximum impact velocity was 6.4 km/s resulting in peak pressures of approximately 120-150 GPa. Copious amounts of projectile melts are preserved as thin glass liners draping the entire crater cavity; some of this liner may be lost by spallation, however. SEM investigations reveal complex surface textures including multistage flow phenomena and distinct temporal deposition sequences of small droplets. Inasmuch as some of the melts were generated at peak pressures greater than 120 GPa, these glasses represent the most severely shocked silicates recovered from laboratory experiments to date. Major element analyses reveal partial loss of alkalis; Na2O loss of 10-15 percent is observed, while K2O loss may be as high as 30-50 percent. Although the observed volatile loss in these projectile melts is significant, it still remains uncertain whether target melts produced on planetary surfaces are severely fractionated by selective volatilization processes.

  3. Study on basalt fiber parameters affecting fiber-reinforced mortar

    Science.gov (United States)

    Orlov, A. A.; Chernykh, T. N.; Sashina, A. V.; Bogusevich, D. V.

    2015-01-01

    This article considers the effect of different dosages and diameters of basalt fibers on tensile strength increase during bending of fiberboard-reinforced mortar samples. The optimal dosages of fiber, providing maximum strength in bending are revealed. The durability of basalt fiber in an environment of cement, by means of microscopic analysis of samples of fibers and fiberboard-reinforced mortar long-term tests is examined. The article also compares the behavior of basalt fiber in the cement stone environment to a glass one and reveals that the basalt fiber is not subject to destruction.

  4. FOAM CONCRETE REINFORCEMENT BY BASALT FIBRES

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2012-10-01

    Full Text Available The authors demonstrate that the foam concrete performance can be improved by dispersed reinforcement, including methods that involve basalt fibres. They address the results of the foam concrete modeling technology and assess the importance of technology-related parameters. Reinforcement efficiency criteria are also provided in the article. Dispersed reinforcement improves the plasticity of the concrete mix and reduces the settlement crack formation rate. Conventional reinforcement that involves metal laths and rods demonstrates its limited application in the production of concrete used for thermal insulation and structural purposes. Dispersed reinforcement is preferable. This technology contemplates the infusion of fibres into porous mixes. Metal, polymeric, basalt and glass fibres are used as reinforcing components. It has been identified that products reinforced by polypropylene fibres demonstrate substantial abradability and deformability rates even under the influence of minor tensile stresses due to the low adhesion strength of polypropylene in the cement matrix. The objective of the research was to develop the type of polypropylene of D500 grade that would demonstrate the operating properties similar to those of Hebel and Ytong polypropylenes. Dispersed reinforcement was performed by the basalt fibre. This project contemplates an autoclave-free technology to optimize the consumption of electricity. Dispersed reinforcement is aimed at the reduction of the block settlement in the course of hardening at early stages of their operation, the improvement of their strength and other operating properties. Reduction in the humidity rate of the mix is based on the plasticizing properties of fibres, as well as the application of the dry mineralization method. Selection of optimal parameters of the process-related technology was performed with the help of G-BAT-2011 Software, developed at Moscow State University of Civil Engineering. The authors also

  5. Inclement Weather Crater Repair Tool Kit

    Science.gov (United States)

    2017-11-30

    9. Corrugated steel quadcons. ....................................................................................................... 14 Figure 10...Saw cutting around crater upheaval. ERDC/GSL TR-17-26 6 The excavation team is responsible for breaking up the damaged portland cement ...in the table located on Sheet 2 in Appendix A. The corrugated steel quadcons (Item 1) are equipped with double swing doors on both ends of the

  6. Fluids, evaporation and precipitates at Gale Crater

    OpenAIRE

    Schwenzer, S. P.; Bridges, J. C.; Leveille, R.; Wiens, R. C.; Mangold, N.; McAdam, A.; Conrad, P.; Kelley, S. P.; Westall, F.; Martín-Torres, F.; Zorzano, M.-P.

    2015-01-01

    The Mars Science Laboratory (MSL) mission landed in Gale Crater, Mars, on 6th August 2012, and has explored the Yellowknife Bay area. The detailed mineralogical and sedimentological studies provide a unique opportunity to characterise the secondary fluids associated with this habitable environment.

  7. Some Studies of Terrestrial Impact Cratering Rate

    Directory of Open Access Journals (Sweden)

    Jetsu L.

    2011-06-01

    Full Text Available In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the “human signal” caused by the rounding of these data into integer numbers. The second study confirmed that the original 28.4 Myr periodicity detection was not significant. The third study revealed that the quality and the quantity of the currently available data would allow detection of real periodicity only if all impacts have been periodic, which cannot be the case. The detection of a periodic signal, if present, requires that more craters should be discovered and the accuracy of age estimates improved. If we sometimes will be able to find the difference between the craters caused by asteroid and comet impacts, the aperiodic component could be removed. The lunar impact craters may eventually provide the required supplementary data.

  8. The Carancas meteorite impact crater, Peru: Geologic surveying and modeling of crater formation and atmospheric passage

    Science.gov (United States)

    Kenkmann, T.; Artemieva, N. A.; Wünnemann, K.; Poelchau, M. H.; Elbeshausen, D.; Núñez Del Prado, H.

    2009-08-01

    The recent Carancas meteorite impact event caused a worldwide sensation. An H4-5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. We present results of a detailed geologic survey of the crater and its ejecta. To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. Depending on the strength properties of the target, the impact energies range between approximately 100-1000 MJ (0.024- 0.24 t TNT). By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12- 14 kms-1) and shallow entry angles (<20°) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40-60°), and an impact velocity of 350-600 ms-1, which is insufficient to produce a shock wave and significant shock effects in target minerals. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. However, these data are in conflict with trajectories inferred from the analysis of

  9. Photosynthesis within Mars' volcanic craters?: Insights from Cerro Negro Volcano, Nicaragua

    Science.gov (United States)

    Rogers, K. L.; Hynek, B. M.; McCollom, T. M.

    2011-12-01

    Discrete locales of sulfate-rich bedrocks exist on Mars and in many cases represent the products of acid-sulfate alteration of martian basalt. In some places, the products have been attributed to hydrothermal processes from local volcanism. In order to evaluate the habitability of such an environment, we are investigating the geochemical and biological composition of active fumaroles at Cerro Negro Volcano, Nicaragua, where fresh basaltic cinders similar in composition to martian basalts are altered by acidic, sulfur-bearing gases. Temperatures at active fumaroles can reach as high as 400°C and the pH of the steam ranges from Cyanobacteria and Ktedonobacteria, however Actinobacteria, alpha-Proteobacteria and Acidobacteria were also identified. Many of the cyanobacterial sequences were similar to those of the eukaryotic Cyanidiales, red algae that inhabit acidic, geothermal environments. Many of sequences related to Ktedonobacteria and Actinobacteria have also been found in acid mine drainage environments. The Archaeal community was far less diverse, with sequences matching those of unclassified Desulfurococcales and unclassified Thermoprotei. These sequences were more distant from isolated species than the bacterial sequences. Similar bacterial and archaeal communities have been found in hot spring environments in Yellowstone National Park, Greenland, Iceland, New Zealand and Costa Rica. Some of Mars' volcanoes were active for billions of years and by analogy to Cerro Negro, may have hosted photosynthetic organisms that could have been preserved in alteration mineral assemblages. Even on a generally cold and dry Mars, volcanic craters likely provided long-lived warm and wet conditions and should be a key target for future exploration assessing habitability.

  10. Descriptive summary of the Grande Ronde Basalt type section, Columbia River Basalt Group

    International Nuclear Information System (INIS)

    Camp, V.E.; Price, S.M.; Reidel, S.P.

    1978-10-01

    The Grande Ronde Basalt type section, located in extreme southeastern Washington, was measured, sampled, and characterized. The section is 800 meters thick and is comprised of 35 Grande Ronde Basalt flows. These flows are divisible into 3 magnetostratiographic units termed, in ascending order, the R 1 , the N 1 , and the R 2 . The R 1 unit is represented by 13 reversely polarized flows; the N 1 unit, by 13 normally polarized flows; and the R 2 , by 9 reversely polarized flows. Chemically, the Grande Ronde Basalt flows are divided into 2 major groups, termed A and B. The compositions of the lower 9 flows, members of Group A, are similar to either the high-Mg Grande Ronde chemical type, the high-Ti Grande Ronde chemical type, or the Pomona chemical type. The compositions of the upper 25 flows, members of Group B, are predominantly similar to the low-Mg Grande Ronde chemical type. Petrographically, the Grande Ronde Basalt flows are generally fine grained and aphyric, and have a intergranular or intersertal micro-texture. Major mineral phases include plagioclase (An/sub 40-60/) and augite; minor mineral phases include pigeonite, orthopyroxene, ilmenite, titanomagnetite, and olivine. Group A flows generally contain more olivine and less pigeonite than do Group B flows. 6 figures, 6 tables

  11. Crystal Stratigraphy of Two Basalts from Apollo 16: Unique Crystallization of Picritic Basalt 606063,10-16 and Very-Low-Titanium Basalt 65703,9-13

    Science.gov (United States)

    Donohue, P. H.; Neal, C. R.; Stevens, R. E.; Zeigler, R. A.

    2014-01-01

    A geochemical survey of Apollo 16 regolith fragments found five basaltic samples from among hundreds of 2-4 mm regolith fragments of the Apollo 16 site. These included a high-Ti vitrophyric basalt (60603,10-16) and one very-low-titanium (VLT) crystalline basalt (65703,9-13). Apollo 16 was the only highlands sample return mission distant from the maria (approx. 200 km). Identification of basaltic samples at the site not from the ancient regolith breccia indicates input of material via lateral transport by post-basin impacts. The presence of basaltic rocklets and glass at the site is not unprecedented and is required to satisfy mass-balance constraints of regolith compositions. However, preliminary characterization of olivine and plagioclase crystal size distributions indicated the sample textures were distinct from other known mare basalts, and instead had affinities to impact melt textures. Impact melt textures can appear qualitatively similar to pristine basalts, and quantitative analysis is required to distinguish between the two in thin section. The crystal stratigraphy method is a powerful tool in studying of igneous systems, utilizing geochemical analyses across minerals and textural analyses of phases. In particular, trace element signatures can aid in determining the ultimate origin of these samples and variations document subtle changes occurring during their petrogenesis.

  12. Experimental simulation of impact cratering on icy satellites

    Science.gov (United States)

    Greeley, R.; Fink, J. H.; Gault, D. E.; Guest, J. E.

    1982-01-01

    Cratering processes on icy satellites were simulated in a series of 102 laboratory impact experiments involving a wide range of target materials. For impacts into homogeneous clay slurries with impact energies ranging from five million to ten billion ergs, target yield strengths ranged from 100 to 38 Pa, and apparent viscosities ranged from 8 to 200 Pa s. Bowl-shaped craters, flat-floored craters, central peak craters with high or little relief, and craters with no relief were observed. Crater diameters increased steadily as energies were raised. A similar sequence was seen for experiment in which impact energy was held constant but target viscosity and strength progressively decreases. The experiments suggest that the physical properties of the target media relative to the gravitationally induced stresses determined the final crater morphology. Crater palimpsests could form by prompt collapse of large central peak craters formed in low target strength materials. Ages estimated from crater size-frequency distributions that include these large craters may give values that are too high.

  13. Shallow and deep fresh impact craters in Hesperia Planum, Mars

    Science.gov (United States)

    Mouginis-Mark, Peter J.; Hayashi, Joan N.

    1993-01-01

    The depths of 109 impact craters about 2-16 km in diameter, located on the ridged plains materials of Hesperia Planum, Mars, have been measured from their shadow lengths using digital Viking Orbiter images (orbit numbers 417S-419S) and the PICS computer software. On the basis of their pristine morphology (very fresh lobate ejecta blankets, well preserved rim crests, and lack of superposed impact craters), 57 of these craters have been selected for detailed analysis of their spatial distribution and geometry. We find that south of 30 deg S, craters less than 6.0 km in diameter are markedly shallower than similar-sized craters equatorward of this latitude. No comparable relationship is observed for morphologically fresh craters greater than 6.0 km diameter. We also find that two populations exist for older craters less than 6.0 km diameter. When craters that lack ejecta blankets are grouped on the basis of depth/diameter ratio, the deeper craters also typically lie equatorward of 30 S. We interpret the spatial variation in crater depth/diameter ratios as most likely due to a poleward increase in volatiles within the top 400 m of the surface at the times these craters were formed.

  14. Emplacement of Columbia River flood basalt

    Science.gov (United States)

    Reidel, Stephen P.

    1998-11-01

    Evidence is examined for the emplacement of the Umatilla, Wilbur Creek, and the Asotin Members of Columbia River Basalt Group. These flows erupted in the eastern part of the Columbia Plateau during the waning phases of volcanism. The Umatilla Member consists of two flows in the Lewiston basin area and southwestern Columbia Plateau. These flows mixed to form one flow in the central Columbia Plateau. The composition of the younger flow is preserved in the center and the composition of the older flow is at the top and bottom. There is a complete gradation between the two. Flows of the Wilbur Creek and Asotin Members erupted individually in the eastern Columbia Plateau and also mixed together in the central Columbia Plateau. Comparison of the emplacement patterns to intraflow structures and textures of the flows suggests that very little time elapsed between eruptions. In addition, the amount of crust that formed on the earlier flows prior to mixing also suggests rapid emplacement. Calculations of volumetric flow rates through constrictions in channels suggest emplacement times of weeks to months under fast laminar flow for all three members. A new model for the emplacement of Columbia River Basalt Group flows is proposed that suggests rapid eruption and emplacement for the main part of the flow and slower emplacement along the margins as the of the flow margin expands.

  15. Commercial nuclear waste repository in basalt

    International Nuclear Information System (INIS)

    Hardy, M.P.; Patricio, J.G.; Heley, W.H.

    1980-06-01

    The Basalt Waste Isolation Project (BWIP) is an ongoing research and engineering effort being conducted by Rockwell Hanford Operations (Rockwell), which is under contract to the US Department of Energy. The objectives of this program are to assess the feasibility of and to provide the technology needed to design and construct a licensed commercial nuclear waste repository in the deep basalt formations underlying the Hanford Site. An extensive preconceptual design effort was undertaken during 1979 to develop a feasible concept that could serve as a reference design for both surface and underground facilities. The preconceptual design utilized existing technology to the greatest extent possible to offer a system design that could be utilized in establishing schedule and cost baseline data, recommend alternatives that require additional study, and develop basic design requirements that would allow evolution of the design process prior to the existence of legislated criteria. This paper provides a description of the concept developed for the subsurface aspects of this nuclear waste repository

  16. Preparation of basalt-based glass ceramics

    Directory of Open Access Journals (Sweden)

    MIHOVIL LOGAR

    2003-06-01

    Full Text Available Local and conventional raw materials–massive basalt from the Vrelo locality on Kopaonik mountain–have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis, optical microscopy and other techniques. Various heat treatments were used, and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO32 and hypersthene ((Mg,FeSiO3 were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8–480 mm with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5–7.5, from 2000–6300 kg/cm2 and from 0.1–0.2 g/cm, respectively.

  17. Degassing of reduced carbon from planetary basalts.

    Science.gov (United States)

    Wetzel, Diane T; Rutherford, Malcolm J; Jacobsen, Steven D; Hauri, Erik H; Saal, Alberto E

    2013-05-14

    Degassing of planetary interiors through surface volcanism plays an important role in the evolution of planetary bodies and atmospheres. On Earth, carbon dioxide and water are the primary volatile species in magmas. However, little is known about the speciation and degassing of carbon in magmas formed on other planets (i.e., Moon, Mars, Mercury), where the mantle oxidation state [oxygen fugacity (fO2)] is different from that of the Earth. Using experiments on a lunar basalt composition, we confirm that carbon dissolves as carbonate at an fO2 higher than -0.55 relative to the iron wustite oxygen buffer (IW-0.55), whereas at a lower fO2, we discover that carbon is present mainly as iron pentacarbonyl and in smaller amounts as methane in the melt. The transition of carbon speciation in mantle-derived melts at fO2 less than IW-0.55 is associated with a decrease in carbon solubility by a factor of 2. Thus, the fO2 controls carbon speciation and solubility in mantle-derived melts even more than previous data indicate, and the degassing of reduced carbon from Fe-rich basalts on planetary bodies would produce methane-bearing, CO-rich early atmospheres with a strong greenhouse potential.

  18. In situ flash X-ray observation of projectile penetration processes and crater cavity growth in porous gypsum target analogous to low-density asteroids

    Science.gov (United States)

    Yasui, Minami; Arakawa, Masahiko; Hasegawa, Sunao; Fujita, Yukihiro; Kadono, Toshihiko

    2012-11-01

    projectile mass, was successfully fitted by a power law equation when another scaling parameter was used for the crater formation in strength regime, πY=Yt/ρtvi2, where Yt is the target material strength, as follows: πV=1.69×10-1πY-0.51. As a result, the crater formed on porous gypsum was revealed to be more than one order of magnitude smaller than that formed on basalt. Based on our experimental results, which visualize how crater cavities on porous cohesive materials grow with projectile penetration, we are able to discuss compression and excavation processes during crater formation quantitatively. This observation enables us to investigate and revise numerical models and crater scaling laws for high-velocity impacts into porous cohesive materials.

  19. Wrinkle Ridges and Young Fresh Crater

    Science.gov (United States)

    2002-01-01

    (Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary 'cousins.' By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called 'wrinkle ridges,' and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That

  20. Hailar crater - A possible impact structure in Inner Mongolia, China

    Science.gov (United States)

    Xiao, Zhiyong; Chen, Zhaoxu; Pu, Jiang; Xiao, Xiao; Wang, Yichen; Huang, Jun

    2018-04-01

    Hailar crater, a probable impact structure, is a circular depression about 300 m diameter in Inner Mongolia, northeast China. With broad elevated rims, the present rim-to-floor depth is 8-20 m. Regional geological background and geomorphological comparison suggest that this feature is likely not formed by surface processes such as salt diapir, karst, aeolian, glacial, or volcanic activity. Its unique occurrence in this region and well-preserved morphology are most consistent with it being a Cenozoic impact crater. Two field expeditions in 2016 and 2017 investigated the origin of this structure, recognizing that (1) no additional craters were identified around Hailar crater in the centimeter-scale digital topography models that were constructed using a drone imaging system and stereo photogrammetry; (2) no bedrock exposures are visible within or adjacent to the crater because of thick regolith coverage, and only small pieces of angular unconsolidated rocks are present on the crater wall and the gently-sloped crater rim, suggesting recent energetic formation of the crater; (3) most samples collected from the crater have identical lithology and petrographic characteristics with the background terrain, but some crater samples contain more abundant clasts and silicate hydrothermal veins, indicating that rocks from depths have been exposed by the crater; (4) no shock metamorphic features were found in the samples after thin section examinations; and (5) a systematic sample survey and iron detector scan within and outside of the crater found no iron-rich meteorites larger than 2 cm in size in a depth of 30 cm. Although no conclusive evidence for an impact origin is found yet, Hailar crater was most likely formed by an impact based on its unique occurrence and comparative geomorphologic study. We suggest that drilling in the crater center is required to verify the impact origin, where hypothesized melt-bearing impactites may be encountered.

  1. Petrology of offshore basalts of Bombay harbour area, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.

    glass are conspicuous. The chemical data indicate that the basalts are tholeiitic. Secondary minerals encountered support the view that the basalts are spilitised. Basalts of this area show affinities to both continental and oceanic types especially...

  2. Hydrogeology of the basalts in the Uruguayan NW

    International Nuclear Information System (INIS)

    Hausman, A.; Fernandez, A.

    1967-01-01

    This work is about the hydrogeological aspects in the NW Uruguayan basaltic area. The results of this research are the main geological, morphological and hydrogeological aspects of the area as well as the characteristics and the color of the basalt and sandstones

  3. Influence of basalt/groundwater interactions on radionuclide migration

    International Nuclear Information System (INIS)

    Vandegrift, G.F.

    1984-01-01

    The work presented here is a partial summary of the experimental results obtained in the Laboratory Analog Program. Two aspects of this effort are (1) the interaction between simulated basaltic groundwater and basalt fissures that were either freshly cleaved or laboratory altered by hydrothermal treatment with the simulated groundwater and (2) the effect of this interaction on radionuclide migration through these basalt fissures. The following conclusions of this study bear heavily on the predicted safety of a basalt repository: Sorption properties of freshly fissured basalt and naturally aged basalt are quite different for different chemical species. Analog experiments predict that aged basalt would be an effective retarder of cesium, but would be much less so for actinide elements. Distribution ratios measured from batch experiments with finely ground rock samples (presenting unaltered rock surfaces) are not a reliable means of predicting radionuclide migration in geological repositories. As the near-repository area is resaturated by groundwater, its ability to retard actinide migration will be degraded with time. Disturbing the natural flow of groundwater through the repository area by constructing and backfilling the repository will modify the composition of groundwater. This modified groundwater is likely to interact with and to modify naturally aged basalt surfaces downstream from the repository

  4. Constructibility issues associated with a nuclear waste repository in basalt

    International Nuclear Information System (INIS)

    Turner, D.A.

    1981-01-01

    This report contains the text and slide reproductions of a speech on nuclear waste disposal in basalt. The presentation addresses the layout of repository access shafts and subsurface facilities resulting from the conceptual design of a nuclear repository in basalt. The constructibility issues that must be resolved prior to construction are described

  5. Use of basaltic waste as red ceramic raw material

    Directory of Open Access Journals (Sweden)

    T. M. Mendes

    Full Text Available Abstract Nowadays, environmental codes restrict the emission of particulate matters, which result in these residues being collected by plant filters. This basaltic waste came from construction aggregate plants located in the Metropolitan Region of Londrina (State of Paraná, Brazil. Initially, the basaltic waste was submitted to sieving (< 75 μm and the powder obtained was characterized in terms of density and particle size distribution. The plasticity of ceramic mass containing 0%, 10%, 20%, 30%, 40% and 50% of basaltic waste was measured by Atterberg method. The chemical composition of ceramic formulations containing 0% and 20% of basaltic waste was determined by X-ray fluorescence. The prismatic samples were molded by extrusion and fired at 850 °C. The specimens were also tested to determine density, water absorption, drying and firing shrinkages, flexural strength, and Young's modulus. Microstructure evaluation was conducted by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. Basaltic powder has similar physical and chemical characteristics when compared to other raw materials, and contributes to ceramic processing by reducing drying and firing shrinkage. Mechanical performance of mixtures containing basaltic powder is equivalent to mixtures without waste. Microstructural aspects such as pore size distribution were modified by basaltic powder; albite phase related to basaltic powder was identified by X-ray diffraction.

  6. Geologic Structures in Crater Walls on Vesta

    Science.gov (United States)

    Mittlefehldt, David W.; Beck, A. W.; Ammannito, E.; Carsenty, U.; DeSanctis, M. C.; LeCorre, L.; McCoy, T. J.; Reddy, V.; Schroeder, S. E.

    2012-01-01

    The Framing Camera (FC) on the Dawn spacecraft has imaged most of the illuminated surface of Vesta with a resolution of apporpx. 20 m/pixel through different wavelength filters that allow for identification of lithologic units. The Visible and Infrared Mapping Spectrometer (VIR) has imaged the surface at lower spatial resolution but high spectral resolution from 0.25 to 5 micron that allows for detailed mineralogical interpretation. The FC has imaged geologic structures in the walls of fresh craters and on scarps on the margin of the Rheasilvia basin that consist of cliff-forming, competent units, either as blocks or semi-continuous layers, hundreds of m to km below the rims. Different units have different albedos, FC color ratios and VIR spectral characteristics, and different units can be juxtaposed in individual craters. We will describe different examples of these competent units and present preliminary interpretations of the structures. A common occurrence is of blocks several hundred m in size of high albedo (bright) and low albedo (dark) materials protruding from crater walls. In many examples, dark material deposits lie below coherent bright material blocks. In FC Clementine color ratios, bright material is green indicating deeper 1 m pyroxene absorption band. VIR spectra show these to have deeper and wider 1 and 2 micron pyroxene absorption bands than the average vestan surface. The associated dark material has subdued pyroxene absorption features compared to the average vestan surface. Some dark material deposits are consistent with mixtures of HED materials with carbonaceous chondrites. This would indicate that some dark material deposits in crater walls are megabreccia blocks. The same would hold for bright material blocks found above them. Thus, these are not intact crustal units. Marcia crater is atypical in that the dark material forms a semi-continuous, thin layer immediately below bright material. Bright material occurs as one or more layers. In

  7. Heavy Cratering near Callisto's South Pole

    Science.gov (United States)

    1997-01-01

    Images from NASA's Galileo spacecraft provide new insights into this region near Callisto's south pole. This two frame mosaic shows a heavily cratered surface with smooth plains in the areas between craters. North is to the top of the image. The smoothness of the plains appears to increase toward the south pole, approximately 480 kilometers (293 miles) south of the bottom of the image. This smoothness of Callisto's surface was not evident in images taken during the 1979 flyby of NASA's Voyager spacecraft because the resolution was insufficient to show the effect. This smooth surface, and the process(es) that cause it, are among the most intriguing aspects of Callisto. Although not fully understood, the process(es) responsible for this smoothing could include erosion by tiny meteorites and energetic ions. Some craters, such as Keelut, the 47 kilometer (29 mile) crater in the lower right corner, have sharp, well defined rims. Keelut contains an inner ring surrounding a central depression about 17 kilometers (11 miles) in diameter. Keelut, and the more irregularly shaped, degraded Reginleif, the 32 kilometer (19.5 mile) crater in the top center of the image, are very shallow and have flat floors. Crater forms can be seen down to less than 2 kilometers (1.2 miles) in diameter in the image. Each picture element (pixel) in this image is approximately 0.68 kilometers (0.41 miles) across.This image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter, on May 6th, 1997. The center of the image is located at 71.3 degrees south latitude, 97.6 degrees west longitude, and was taken when the spacecraft was approximately 35,470 kilometers (21,637 miles) from Callisto.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http

  8. Hydrothermal interactions of cesium and strontium phases from spent unreprocessed fuel with basalt phases and basalts

    International Nuclear Information System (INIS)

    Komarneni, S.; Scheetz, B.E.; McCarthy, G.J.; Coons, W.E.

    1980-03-01

    This investigation is a segment of an extensive research program aimed at investigating the feasibility of long-term, subsurface storage of commercial nuclear waste. Specifically, it is anticipated that the waste will be housed in a repository mined from the basalt formations which lie beneath the Hanford Site. The elements monitored during the present experiments were Cs and Sr. These two elements represent significant biohazards if released from a repository and are the major heat producing radionuclides present in commercial radioactive waste. Several Cs phases and/or solutions were reacted with either isolated basalt phases or bulk-rock basalt, and the resulting solids and solutions were analyzed. The hydrothermal reactivity of SrZrO 3 , which is believed to be a probable host for Sr in SFE was investigated. While so far no evidence exists which indicates that Sr is present in a water soluble phase in spent fuel elements (SFE), detailed investigation of a potential hazard is warranted. This investigation has determined that some Cs compounds likely to be stable components of spent fuel (i.e., CsOH, Cs 2 MoO 4 , Cs 2 U 2 O 7 ) have significant hydrothermal solubilities. These solubilities are greatly decreased in the presence of basalt and/or basalt minerals. The decrease in the amount of Cs in solution results from reactions which form pollucite and/or CsAlSiO 4 , with the production of pollucite exceeding that of CsAlSiO 4 . Dissolution of β-Cs 2 U 2 O 7 implies solubilizing a uranium species to an undetermined extent. The production of schoepite (UO 3 .3H 2 O) during some experiments containing basalt phases, indicates a tendency to oxidize U 4+ to U 6+ . When diopside (nominally CaMgSi 2 O 6 ) and β-Cs 2 U 2 O 7 were hydrothermally reacted, at 300 0 C both UO 2 and UO 3 .3H 2 O were produced. Experiments on SrZrO 3 show it to be an unreactive phase

  9. Hydrothermal interactions of cesium and strontium phases from spent unreprocessed fuel with basalt phases and basalts

    Energy Technology Data Exchange (ETDEWEB)

    Komarneni, S.; Scheetz, B.E.; McCarthy, G.J.; Coons, W.E.

    1980-03-01

    This investigation is a segment of an extensive research program aimed at investigating the feasibility of long-term, subsurface storage of commercial nuclear waste. Specifically, it is anticipated that the waste will be housed in a repository mined from the basalt formations which lie beneath the Hanford Site. The elements monitored during the present experiments were Cs and Sr. These two elements represent significant biohazards if released from a repository and are the major heat producing radionuclides present in commercial radioactive waste. Several Cs phases and/or solutions were reacted with either isolated basalt phases or bulk-rock basalt, and the resulting solids and solutions were analyzed. The hydrothermal reactivity of SrZrO/sub 3/, which is believed to be a probable host for Sr in SFE was investigated. While so far no evidence exists which indicates that Sr is present in a water soluble phase in spent fuel elements (SFE), detailed investigation of a potential hazard is warranted. This investigation has determined that some Cs compounds likely to be stable components of spent fuel (i.e., CsOH, Cs/sub 2/MoO/sub 4/, Cs/sub 2/U/sub 2/O/sub 7/) have significant hydrothermal solubilities. These solubilities are greatly decreased in the presence of basalt and/or basalt minerals. The decrease in the amount of Cs in solution results from reactions which form pollucite and/or CsAlSiO/sub 4/, with the production of pollucite exceeding that of CsAlSiO/sub 4/. Dissolution of ..beta..-Cs/sub 2/U/sub 2/O/sub 7/ implies solubilizing a uranium species to an undetermined extent. The production of schoepite (UO/sub 3/.3H/sub 2/O) during some experiments containing basalt phases, indicates a tendency to oxidize U/sup 4 +/ to U/sup 6 +/. When diopside (nominally CaMgSi/sub 2/O/sub 6/) and ..beta..-Cs/sub 2/U/sub 2/O/sub 7/ were hydrothermally reacted, at 300/sup 0/C both UO/sub 2/ and UO/sub 3/.3H/sub 2/O were produced. Results of experiments on SrZrO/sub 3/ show it to be

  10. [Determination of Total Iron and Fe2+ in Basalt].

    Science.gov (United States)

    Liu, Jian-xun; Chen, Mei-rong; Jian, Zheng-guo; Wu, Gang; Wu, Zhi-shen

    2015-08-01

    Basalt is the raw material of basalt fiber. The content of FeO and Fe2O3 has a great impact on the properties of basalt fibers. ICP-OES and dichromate method were used to test total Fe and Fe(2+) in basalt. Suitable instrument parameters and analysis lines of Fe were chosen for ICP-OES. The relative standard deviation (RSD) of ICP-OES is 2.2%, and the recovery is in the range of 98%~101%. The method shows simple, rapid and highly accurate for determination of total Fe and Fe(2+) in basalt. The RSD of ICP-OES and dichromate method is 0.42% and 1.4%, respectively.

  11. Aqueous alteration detection in Tikhonravov crater, Mars

    Science.gov (United States)

    Mancarella, F.; Fonti, S.; Alemanno, G.; Orofino, V.; Blanco, A.

    2018-03-01

    The existence of a wet period lasting long enough to allow the development of elementary forms of life on Mars has always been a very interesting issue. Given this perspective, the research for geological markers of such occurrences has been continually pursued. Once a favorable site is detected, effort should be spent to get as much information as possible aimed at a precise assessment of the genesis and evolution of the areas showing the selected markers. In this work, we discuss the recent finding of possible deposits pointing to the past existence of liquid water in Tikhonravov crater located in Arabia Terra. Comparison of CRISM spectra and those of laboratory minerals formed by aqueous alteration has led us to the conclusion that the studied areas within the impact crater host phyllosilicates deposits. In addition, analysis of the CRISM spectra has resulted in the tentative identification of carbonates mixed with phyllosilicates.

  12. Layers of 'Cabo Frio' in 'Victoria Crater'

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  13. Impact cratering experiments in Bingham materials and the morphology of craters on Mars and Ganymede

    Science.gov (United States)

    Fink, J. H.; Greeley, R.; Gault, D. E.

    1982-01-01

    Results from a series of laboratory impacts into clay slurry targets are compared with photographs of impact craters on Mars and Ganymede. The interior and ejecta lobe morphology of rampart-type craters, as well as the progression of crater forms seen with increasing diameter on both Mars and Ganymede, are equalitatively explained by a model for impact into Bingham materials. For increasing impact energies and constant target rheology, laboratory craters exhibit a morphologic progression from bowl-shaped forms that are typical of dry planetary surfaces to craters with ejecta flow lobes and decreasing interior relief, characteristic of more volatile-rich planets. A similar sequence is seen for uniform impact energy in slurries of decreasing yield strength. The planetary progressions are explained by assuming that volatile-rich or icy planetary surfaces behave locally in the same way as Bingham materials and produce ejecta slurries with yield strenghs and viscosities comparable to terrestrial debris flows. Hypothetical impact into Mars and Ganymede are compared, and it is concluded that less ejecta would be produced on Ganymede owing to its lower gravitational acceleration, surface temperature, and density of surface materials.

  14. Low-velocity impact cratering experiments in granular slopes

    Science.gov (United States)

    Hayashi, Kosuke; Sumita, Ikuro

    2017-07-01

    Low-velocity impact cratering experiments are conducted in sloped granular targets to study the effect of the slope angle θ on the crater shape and its scales. We use two types of granular matter, sand and glass beads, former of which has a larger friction coefficient μs = tanθr , where θr is the angle of repose. Experiments show that as θ increases, the crater becomes shallower and elongated in the direction of the slope. Furthermore the crater floor steepens in the upslope side and a thick rim forms in the downslope side, thus forming an asymmetric profile. High-speed images show that these features are results of ejecta being dispersed farther towards the downslope side and the subsequent avalanche which buries much of the crater floor. Such asymmetric ejecta dispersal can be explained by combining the Z-model and a ballistic model. Using the topographic maps of the craters, we classify crater shape regimes I-III, which transition with increasing θ : a full-rim crater (I), a broken-rim crater (II), and a depression (III). The critical θ for the regime transitions are larger for sand compared to glass beads, but collapse to close values when we use a normalized slope θ^ = tanθ / tanθr . Similarly we derive θ^-dependences of the scaled crater depth, length, width and their ratios which collapse the results for different targets and impact energies. We compare the crater profiles formed in our experiments with deep craters on asteroid Vesta and find that some of the scaled profiles nearly overlap and many have similar depth / length ratios. This suggests that these Vestan craters may also have formed in the gravity regime and that the formation process can be approximated by a granular flow with a similar effective friction coefficient.

  15. Basalt alteration and basalt-waste interaction in the Pasco Basin of Washington State. Final report

    International Nuclear Information System (INIS)

    Benson, L.V.; Carnahan, C.L.; Apps, J.A.; Mouton, C.A.; Corrigan, D.J.; Frisch, C.J.; Shomura, L.K.

    1978-09-01

    A study was conducted to determine the nature of the minerals which coat vesicle and fracture surfaces in the Grande Ronde Basalt Formation, simulate the mass transfer which led to their precipitation, and predict the mass transfer associated with the dissolution of spent unreprocessed fuel (SURF). Scanning electron microscopy (SEM), petrographic, x-ray diffraction (XRD), and electron microprobe (EMP) analyses have been made on a series of samples taken from 1100 ft (335.3 m) of core from core hole DC2. Preliminary simulations of the mass transfer associated with basalt dissolution in a thermodynamically closed system have been accomplished. In addition two mass transfer codes have been modified to facilitate data base changes. Thermochemical data for uranium and plutonium have been collected and converted to standard state conditions. These data will be critically evaluated and input to the mass transfer data base in the near future

  16. The isostatic state of Mead crater

    Science.gov (United States)

    Banerdt, W. B.; Konopliv, A. S.; Rappaport, N. J.; Sjogren, W. L.; Grimm, R. E.; Ford, P. G.

    1994-01-01

    We have analyzed high-resolution Magellan Doppler tracking data over Mead crater, using both line-of-sight and spherical harmonic methods, and have found a negative gravity anomaly of about 4-5 mgal (at spacecraft altitude, 182 km). This is consistent with no isostatic compensation of the present topography; the uncertainty in the analysis allows perhaps as much as 30% compensation at shallow dpeths (approximately 25 km). This is similar to observations of large craters on Earth, which are not generally compensated, but contrasts with at least some lunar basins which are inferred to have large Moho uplifts and corresponding positive Bouguer anomalies. An uncompensated load of this size requires a lithosphere with an effective elastic lithosphere thickness greater than 30 km. In order for the crust-mantle boundary not to have participated in the deformation associated with the collapse of the transient cavity during the creation of the crater, the yield strength near the top of the mantle must have been significantly higher on Earth and Venus than on the Moon at the time of basin formation. This might be due to increased strength against frictional sliding at the higher confining pressures within the larger planets. Alternatively, the thinner crusts of Earth and Venus compared to that of the Moon may result in higher creep strength of the upper mantle at shallower depths.

  17. Ejecta from single-charge cratering explosions

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, R H

    1970-05-15

    The objective was to obtain experimental data tracing the location of ejecta to its origin within the crater region. The experiment included ten high-explosive spherical charges weighing from 8 to 1000 pounds and detonated in a playa dry lake soil on the Tonopah Test Range. Each event included from 24 to 40 locations of distinctly different tracer material embedded in a plane in the expected crater region. Tracers consisted of glass, ceramic and bugle beads, chopped metal, and plastic wire. Results of this experiment yielded data on tracer dispersion as a function of charge weight, charge burial depth and tracer emplacement position. Tracer pattern parameters such as center-of-tracer mass, range to center-of-tracer mass, and angle to center-of-tracer mass were determined. There is a clear tendency for range (to center-of-tracer mass) and the size of the dispersion pattern to decrease as tracer emplacement depth increases. Increasing tracer emplacement depth and range tends to decrease the area over which tracers are dispersed on the ground surface. Tracers at the same scaled position relative to the charge were deposited closer to the crater (on a scaled basis) as charge weight was increased. (author)

  18. The central uplift of Ritchey crater, Mars

    Science.gov (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

    2015-01-01

    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  19. The central uplift of Ritchey crater, Mars

    Science.gov (United States)

    Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.

    2015-05-01

    Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.

  20. Strontium stable isotope behaviour accompanying basalt weathering

    Science.gov (United States)

    Burton, K. W.; Parkinson, I. J.; Gíslason, S. G. R.

    2016-12-01

    The strontium (Sr) stable isotope composition of rivers is strongly controlled by the balance of carbonate to silicate weathering (Krabbenhöft et al. 2010; Pearce et al. 2015). However, rivers draining silicate catchments possess distinctly heavier Sr stable isotope values than their bedrock compositions, pointing to significant fractionation during weathering. Some have argued for preferential release of heavy Sr from primary phases during chemical weathering, others for the formation of secondary weathering minerals that incorporate light isotopes. This study presents high-precision double-spike Sr stable isotope data for soils, rivers, ground waters and estuarine waters from Iceland, reflecting both natural weathering and societal impacts on those environments. The bedrock in Iceland is dominantly basaltic, d88/86Sr ≈ +0.27, extending to lighter values for rhyolites. Geothermal waters range from basaltic Sr stable compositions to those akin to seawater. Soil pore waters reflect a balance of input from primary mineral weathering, precipitation and litter recycling and removal into secondary phases and vegetation. Rivers and ground waters possess a wide range of d88/86Sr compositions from +0.101 to +0.858. Elemental and isotope data indicate that this fractionation primarily results from the formation or dissolution of secondary zeolite (d88/86Sr ≈ +0.10), but also carbonate (d88/86Sr ≈ +0.22) and sometimes anhydrite (d88/86Sr ≈ -0.73), driving the residual waters to heavier or lighter values, respectively. Estuarine waters largely reflect mixing with seawater, but are also be affected by adsorption onto particulates, again driving water to heavy values. Overall, these data indicate that the stability and nature of secondary weathering phases, exerts a strong control on the Sr stable isotope composition of silicate rivers. [1] Krabbenhöft et al. (2010) Geochim. Cosmochim. Acta 74, 4097-4109. [2] Pearce et al. (2015) Geochim. Cosmochim. Acta 157, 125-146.

  1. Cratering Studies in Thin Plastic Films

    Science.gov (United States)

    Shu, A. J.; Bugiel, S.; Gruen, E.; Hillier, J.; Horanyi, M.; Munsat, T. L.; Srama, R.

    2013-12-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions and shape of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. LS-Dyna, a smoothed particle hydrodynamics (SPH) code from the Livermore Software Technology Corp. was chosen to simulate micrometeorite impacts. SPH is known to be well suited to the large deformities found in hypervelocity impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Material properties are accounted for using the Grüneisen Equation of State. The results of the SPH model can

  2. Morphological Indicators of a Mascon Beneath Ceres's Largest Crater, Kerwan

    Science.gov (United States)

    Bland, M. T.; Ermakov, A. I.; Raymond, C. A.; Williams, D. A.; Bowling, T. J.; Preusker, F.; Park, R. S.; Marchi, S.; Castillo-Rogez, J. C.; Fu, R. R.; Russell, C. T.

    2018-02-01

    Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long-term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact-induced uplift of the high-density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest-degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin-associated gravity anomalies, although their origin may differ substantially.

  3. A schematic model of crater modification by gravity

    Science.gov (United States)

    Melosh, H. J.

    1982-01-01

    The morphology of craters found on planets and moons of the solar system is examined and a development model which can account for the observed crater characteristics is discussed. The prompt collapse of craters to form flat floors, terraced walls, and central peak structures is considered to be the result of an approximate Bingham plastic rheology of the material surrounding the crater. This rheology is induced dynamically by the strong incoherent acoustic 'noise' accompanying excavation of the crater. Central pits, peak rings, and other multiple symmetric-profile rings originate by oscillation of this fluid. Large craters with transient depths comparable to the lithosphere thickness are subject to collapse by fragmentation of the lithosphere as well as fluidization. The considered concepts are developed mathematically. A model emerges which appears capable of explaining most of the qualitative features of large impact structures.

  4. Geological mapping of lunar highland crater Lalande: Topographic configuration, morphology and cratering process

    Science.gov (United States)

    Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian; Liu, ChangQing; Bi, Xiangyu

    2018-02-01

    Highland crater Lalande (4.45°S, 8.63°W; D = 23.4 km) is located on the PKT area of the lunar near side, southeast of the Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, the highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of Lalande's floor with regular circle or ellipse shapes. They are ∼250-680 m wide and ∼30-91 m high with maximum flank slopes >20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. We estimated the absolute model ages of the ejecta deposits, several melt ponds and the hummocky floor and determined the ratio of diameter and depth of the crater Lalande. In addition, we found some similar bugle features within other Copernican-aged craters and there were no volcanic source vents on Lalande's floor. Thus, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the floor. Based on Kaguya Terrain Camera (TC) ortho-mosaic and Digital Terrain Model (DTM) data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features provided us a chance to understand some details of the cratering process and elevation differences on the floor. We proposed that subsidence due to melt cooling, late-stage wall collapse and rocks uplifted from beneath the surface could be the possible causes of the observed elevation differences on Lalande's floor.

  5. Impact spacecraft imagery and comparative morphology of craters

    International Nuclear Information System (INIS)

    Moutsoulas, M.; Piteri, S.

    1979-01-01

    The use of hard-landing 'simple' missions for wide-scale planetary exploration is considered. As an example of their imagery potentialities, Ranger VII data are used for the study of the morphological characteristics of 16 Mare Cognitum craters. The morphological patterns of lunar craters, expressed in terms of the Depth/Diameter ratios appear to be in most cases independent of the crater location or size. (Auth.)

  6. Crater populations in the early history of Mercury

    International Nuclear Information System (INIS)

    Guest, J.E.; Gault, D.E.

    1976-01-01

    Crater populations on two major geologic units of Mercury have been classified into three morphologic types which characterize their state of degradation. The results indicate that one or more processes either prior to or contemporary with the formation of the 1300 km diameter Caloris Planitia reduced the population of fresh craters smaller than 70--80 km diameter and totally erased the population of fresh craters smaller than 20--30 km

  7. Geologic map of Tooting crater, Amazonis Planitia region of Mars

    Science.gov (United States)

    Mouginis-Mark, Peter J.

    2015-01-01

    Tooting crater has a diameter of 27.2 km, and formed on virtually flat lava flows within Amazonis Planitia ~1,300 km west of the summit of Olympus Mons volcano, where there appear to have been no other major topographic features prior to the impact. The crater formed in an area ~185 x 135 km that is at an elevation between −3,870 m and −3,874 m relative to the Mars Orbiter Laser Altimeter (MOLA) Mars datum. This fortuitous situation (for example, a bland, horizontal target) allows the geometry of the crater and the thickness of the ejecta blanket to be accurately determined by subtracting the appropriate elevation of the surrounding landscape (−3,872 m) from the individual MOLA measurements across the crater. Thus, for the first time, it is possible to determine the radial decrease of ejecta thickness as a function of distance away from the rim crest. On the basis of the four discrete ejecta layers surrounding the crater cavity, Tooting crater is classified as a Multiple-Layered Ejecta (MLE) crater. By virtue of the asymmetric distribution of secondary craters and the greater thickness of ejecta to the northeast, Morris and others (2010) proposed that Tooting crater formed by an oblique impact from the southwest. The maximum range of blocks that produced identifiable secondary craters is ~500 km (~36.0 crater radii) from the northeast rim crest. In contrast, secondary craters are only identifiable ~215 km (15.8 radii) to the southeast and 225 km (16.5 radii) to the west.

  8. Simulating the structure of gypsum composites using pulverized basalt waste

    Directory of Open Access Journals (Sweden)

    Buryanov Аleksandr

    2017-01-01

    Full Text Available This paper examines the possibility of simulating the structure of gypsum composite modified with basalt dust waste to make materials and products based on it. Structural simulating of the topological space in gypsum modified composite by optimizing its grain-size composition highly improves its physical and mechanical properties. Strength and density tests have confirmed the results of the simulation. The properties of modified gypsum materials are improved by obtaining of denser particle packing in the presence of hemihydrate of finely dispersed basalt and plasticizer particles in the system, and by engaging basalt waste in the structuring process of modified gypsum stone.

  9. Basaltic volcanic episodes of the Yucca Mountain region

    International Nuclear Information System (INIS)

    Crowe, B.M.

    1990-01-01

    The purpose of this paper is to summarize briefly the distribution and geologic characteristics of basaltic volcanism in the Yucca Mountain region during the last 10--12 Ma. This interval largely postdates the major period of silicic volcanism and coincides with and postdates the timing of major extensional faulting in the region. Field and geochronologic data for the basaltic rocks define two distinct episodes. The patterns in the volume and spatial distribution of these basaltic volcanic episodes in the central and southern part of the SNVF are used as a basis for forecasting potential future volcanic activity in vicinity of Yucca Mountain. 33 refs., 2 figs

  10. Determining long-term regional erosion rates using impact craters

    Science.gov (United States)

    Hergarten, Stefan; Kenkmann, Thomas

    2015-04-01

    More than 300,000 impact craters have been found on Mars, while the surface of Moon's highlands is even saturated with craters. In contrast, only 184 impact craters have been confirmed on Earth so far with only 125 of them exposed at the surface. The spatial distribution of these impact craters is highly inhomogeneous. Beside the large variation in the age of the crust, consumption of craters by erosion and burial by sediments are the main actors being responsible for the quite small and inhomogeneous crater record. In this study we present a novel approach to infer long-term average erosion rates at regional scales from the terrestrial crater inventory. The basic idea behind this approach is a dynamic equilibrium between the production of new craters and their consumption by erosion. It is assumed that each crater remains detectable until the total erosion after the impact exceeds a characteristic depth depending on the crater's diameter. Combining this model with the terrestrial crater production rate, i.e., the number of craters per unit area and time as a function of their diameter, allows for a prediction of the expected number of craters in a given region as a function of the erosion rate. Using the real crater inventory, this relationship can be inverted to determine the regional long-term erosion rate and its statistical uncertainty. A limitation by the finite age of the crust can also be taken into account. Applying the method to the Colorado Plateau and the Deccan Traps, both being regions with a distinct geological history, yields erosion rates in excellent agreement with those obtained by other, more laborious methods. However, these rates are formally exposed to large statistical uncertainties due to the small number of impact craters. As higher crater densities are related to lower erosion rates, smaller statistical errors can be expected when large regions in old parts of the crust are considered. Very low long-term erosion rates of less than 4

  11. Floor-Fractured Craters through Machine Learning Methods

    Science.gov (United States)

    Thorey, C.

    2015-12-01

    Floor-fractured craters are impact craters that have undergone post impact deformations. They are characterized by shallow floors with a plate-like or convex appearance, wide floor moats, and radial, concentric, and polygonal floor-fractures. While the origin of these deformations has long been debated, it is now generally accepted that they are the result of the emplacement of shallow magmatic intrusions below their floor. These craters thus constitute an efficient tool to probe the importance of intrusive magmatism from the lunar surface. The most recent catalog of lunar-floor fractured craters references about 200 of them, mainly located around the lunar maria Herein, we will discuss the possibility of using machine learning algorithms to try to detect new floor-fractured craters on the Moon among the 60000 craters referenced in the most recent catalogs. In particular, we will use the gravity field provided by the Gravity Recovery and Interior Laboratory (GRAIL) mission, and the topographic dataset obtained from the Lunar Orbiter Laser Altimeter (LOLA) instrument to design a set of representative features for each crater. We will then discuss the possibility to design a binary supervised classifier, based on these features, to discriminate between the presence or absence of crater-centered intrusion below a specific crater. First predictions from different classifier in terms of their accuracy and uncertainty will be presented.

  12. Surface age of venus: use of the terrestrial cratering record

    International Nuclear Information System (INIS)

    Schaber, G.G.; Shoemaker, E.M.; Kozak, R.C.

    1987-01-01

    The average crater age of Venus' northern hemisphere may be less than 250 m.y. assuming equivalence between the recent terrestrial cratering rate and that on Venus for craters ≥ 20 km in diameter. For craters larger than this threshold size, below which crater production is significantly affected by the Venusian atmosphere, there are fairly strong observational grounds for concluding that such an equivalence in cratering rates on Venus and Earth may exist. However, given the uncertainties in the role of both active and inactive comet nuclei in the cratering history of Earth, we conclude that the age of the observed surface in the northern hemisphere of Venus could be as great as the 450-m.y. mean age of the Earth's crust. The observed surface of Venus might be even older, but no evidence from the crater observations supports an age as great as 1 b.y. If the age of the observed Venusian surface were 1 b.y., it probably should bear the impact scars of a half dozen or more large comet nuclei that penetrated the atmosphere and formed craters well over 100 km in diameter. Venera 15/16 mapped only about 25% of Venus; the remaining 75% may tell us a completely different story

  13. Field-trip guide to Mount St. Helens, Washington - An overview of the eruptive history and petrology, tephra deposits, 1980 pyroclastic density current deposits, and the crater

    Science.gov (United States)

    Pallister, John S.; Clynne, Michael A.; Wright, Heather M.; Van Eaton, Alexa R.; Vallance, James W.; Sherrod, David R.; Kokelaar, B. Peter

    2017-08-02

    This field trip will provide an introduction to several fascinating features of Mount St. Helens. The trip begins with a rigorous hike of about 15 km from the Johnston Ridge Observatory (9 km north-northeast of the crater vent), across the 1980 Pumice Plain, to Windy Ridge (3.6 km northeast of the crater vent) to examine features that document the dynamics and progressive emplacement of pyroclastic flows. The next day, we examine classic tephra outcrops of the past 3,900 years and observe changes in thickness and character of these deposits as we traverse their respective lobes. We examine clasts in the deposits and discuss how the petrology and geochemistry of Mount St. Helens deposits reveal the evolution of the magmatic system through time. We also investigate the stratigraphy of the 1980 blast deposit and review the chronology of this iconic eruption as we travel through the remains of the blown-down forest. The third day is another rigorous hike, about 13 km round trip, climbing from the base of Windy Ridge (elevation 1,240 m) to the front of the Crater Glacier (elevation 1,700 m). En route we examine basaltic andesite and basalt lava flows emplaced between 1,800 and 1,700 years before present, a heterolithologic flow deposit produced as the 1980 blast and debris avalanche interacted, debris-avalanche hummocks that are stranded on the north flank and in the crater mouth, and shattered dacite lava domes that were emplaced between 3,900 and 2,600 years before present. These domes underlie the northern part of the volcano. In addition, within the crater we traverse well-preserved pyroclastic-flow deposits that were emplaced on the crater floor during the summer of 1980, and a beautiful natural section through the 1980 deposits in the upper canyon of the Loowit River.Before plunging into the field-trip log, we provide an overview of Mount St. Helens geology, geochemistry, petrology, and volcanology as background. The volcano has been referred to as a

  14. Characteristics of ejecta and alluvial deposits at Meteor Crater, Arizona and Odessa Craters, Texas: Results from ground penetrating radar

    Science.gov (United States)

    Grant, J. A.; Schultz, P. H.

    1991-01-01

    Previous ground penetrating radar (GRP) studies around 50,000 year old Meteor Crater revealed the potential for rapid, inexpensive, and non-destructive sub-surface investigations for deep reflectors (generally greater than 10 m). New GRP results are summarized focusing the shallow sub-surfaces (1-2 m) around Meteor Crater and the main crater at Odessa. The following subject areas are covered: (1) the thickness, distribution, and nature of the contact between surrounding alluvial deposits and distal ejecta; and (2) stratigraphic relationships between both the ejecta and alluvium derived from both pre and post crater drainages. These results support previous conclusions indicating limited vertical lowering (less than 1 m) of the distal ejecta at Meteor Crater and allow initial assessment of the gradational state if the Odessa craters.

  15. Melt rock components in KREEPy breccia 15205: Petrography and mineral chemistry of KREEP basalts and quartz-normative mare basalts

    Science.gov (United States)

    Shervais, John W.; Vetter, Scott K.

    1993-05-01

    Many current models for the origin of lunar highland rocks feature as an essential component the assimilation of KREEPy material by primitive magmas parental to the Mg-rich suite and alkali suite plutonic rocks. Similar models have also been proposed for the origin of various mare basalt suites. However, any model which considers assimilation of KREEP an important petrologic process must sooner-or-later deal with the question: what is KREEP? Because pristine KREEP basalts are rare, and most known samples are small (e.g., 15382/15386), the geochemical variability of KREEP basalts is poorly known. Other KREEP compositions which are commonly used in these models include the hypothetical 'high-K KREEP' component of Warren and Wasson, which is derived from Apollo 14 soil data, and the 'superKREEP' quartz-monzodiorite 15405. Lunar breccia 15205 is a polymict regolith breccia that consists of approximately 20% KREEP basalt clasts and 20% quartz-normative basalt clasts in a KREEP-rich matrix. Bulk rock mixing calculations show that this sample comprises about 84% KREEP. The clasts range up to 1 cm in size, but most are considerably smaller. The primary aim is to characterize pristine KREEP basalts petrographically, to establish the range in chemical compositions of KREEP basalts, and to test models that were proposed for their origin. In addition, we may be able to extend the compositional range recognized in the quartz-normative basalt suite and cast some light on its origin as well. Preliminary whole rock geochemical data on the KREEP basalts are presented in a companion paper by M.M. Lindstrom and co-workers. Concentration is on petrography and mineral chemistry of these clasts, and the implications these data have for the origin of the different melt rock suites.

  16. Soft Rock Yields Clues to Mars' Past

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1 This image taken by the Mars Exploration Rover Spirit shows the rock outcrop dubbed 'Clovis.' The rock was discovered to be softer than other rocks studied so far at Gusev Crater after the rover easily ground a hole into it with its rock abrasion tool. Spirit's solar panels can be seen in the foreground. This image was taken by the rover's navigation camera on sol 205 (July 31, 2004). Elemental Trio Found in 'Clovis' Figure 1 above shows that the interior of the rock dubbed 'Clovis' contains higher concentrations of sulfur, bromine and chlorine than basaltic, or volcanic, rocks studied so far at Gusev Crater. The data were taken by the Mars Exploration Rover Spirit's alpha particle X-ray spectrometer after the rover dug into Clovis with its rock abrasion tool. The findings might indicate that this rock was chemically altered, and that fluids once flowed through the rock depositing these elements.

  17. A model for the dynamics of crater-centered intrusion: Application to lunar floor-fractured craters

    Science.gov (United States)

    Thorey, Clément; Michaut, Chloé

    2014-01-01

    Lunar floor-fractured craters are a class of craters modified by post-impact mechanisms. They are defined by distinctive shallow floors that are convex or plate-like, sometimes with a wide floor moat bordering the wall region. Radial, concentric, and polygonal floor fractures suggest an endogenous process of modification. Two mechanisms have been proposed to account for such deformations: viscous relaxation and spreading of a magma intrusion at depth below the crater. To test the second assumption and bring more constraints on the intrusion process, we develop a model for the dynamics of magma spreading below an elastic overlying layer with a crater-like topography. As predicted in earlier more qualitative studies, the increase in lithostatic pressure at the crater wall zone prevents the intrusion from spreading laterally, leading to the thickening of the intrusion. Additionally, our model shows that the final crater floor appearance after the uplift, which can be convex or flat, with or without a circular moat bordering the wall zone, depends on the elastic thickness of the layer overlying the intrusion and on the crater size. Our model provides a simple formula to derive the elastic thickness of the overlying layer hence a minimum estimate for the intrusion depth. Finally, our model suggests that crust redistribution by cratering must have controlled magma ascent below most of these craters.

  18. Engineered barrier development for a nuclear waste repository in basalt

    International Nuclear Information System (INIS)

    Smith, M.J.

    1980-05-01

    The BWIP Engineered Barrier Program has been developed to provide an integrated approach to the development of site-specific Engineered Barrier assemblages for a repository located in basalt. The goal of this program is to specify engineered and natural barriers which will ensure that nuclear and non-radioactive hazardous materials emplaced in a repository in basalt do not exceed acceptable rates of release to the biosphere. A wide range of analytical and experimental activities related to the basalt repository environment, waste package environment, waste/barrier/rock interactions, and barrier performance assessment provide the basis for selection of systems capable of meeting licensing requirements. Work has concentrated on specifying and testing natural and man-made materials which can be used to plug boreholes in basalt and which can be used as multiple barriers to surround nuclear waste forms and containers. The Engineered Barriers Program is divided into two major activities: multiple barrier studies and borehole plugging. 8 figures, 4 tables

  19. Geochemical characterization of oceanic basalts using artificial neural network

    Digital Repository Service at National Institute of Oceanography (India)

    Das, P.; Iyer, S.D.

    method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB). Artificial Neural Network (ANN) technique as a supervised Learning Vector Quantisation (LVQ) is applied to identify the inherent...

  20. Alteration of basaltic glasses from the Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.

    Textural, mineralogical and compositional characteristics of basaltic glasses from the Central Indian Ocean show them to be altered to varying extents through their interaction with the seawater, resulting in the formation of palagonite. The major...

  1. A note on incipient spilitisation of central Indian basin basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Karisiddaiah, S.M.; Iyer, S.D.

    Rocks dredged in the vicinity of the 79 degrees E fracture zone, in the Central Indian Basin, are sub-alkaline basalts, which are regarded as precursors to spilites. The minerals identified are mainly albitic plagioclase, augite, olivine, and less...

  2. [Comparative carcinogenic properties of basalt fiber and chrysotile-asbestos].

    Science.gov (United States)

    Nikitina, O V; Kogan, F M; Vanchugova, N N; Frash, V N

    1989-01-01

    In order to eliminate asbestos adverse effect on workers' health it was necessary to use mineral rayon, primarily basalt fibre, instead of asbestos. During a chronic experiment on animals the oncogenicity of 2 kinds of basalt fibre was studied compared to chrysotile asbestos. The dust dose of 25 mg was twice administered by intraperitonial route. All types of dust induced the onset of intraperitonial mesotheliomas but neoplasm rates were significantly lower in the groups exposed to basalt fibre. There was no credible data on the differences between the groups exposed to various types of basalt fibre. Since the latter produced some oncogenic effect, it was necessary to develop a complex of antidust measures, fully corresponding to the measures adopted for carcinogenic dusts.

  3. Trace Element Abundances in Eucrite Basalts: Enrichment or Depletion?

    Science.gov (United States)

    Castle, N. R.

    2018-05-01

    It is not clear how incompatible trace element (ITE) variation in eucrite basalts originated. Here, mechanisms for relative ITE enrichment or depletion are experimentally evaluated in an attempt to reconcile the Stannern and main group eucrites.

  4. Cratering record in the inner solar system: Implications for earth

    International Nuclear Information System (INIS)

    Barlow, N.G.

    1988-01-01

    Internal and external processes have reworked the Earth's surface throughout its history. In particular, the effect of meteorite impacts on the early history of the earth is lost due to fluvial, aeolian, volcanic and plate tectonic action. The cratering record on other inner solar system bodies often provides the only clue to the relative cratering rates and intensities that the earth has experienced throughout its history. Of the five major bodies within the inner solar system, Mercury, Mars, and the Moon retain scars of an early episode of high impact rates. The heavily cratered regions on Mercury, Mars, and the Moon show crater size-frequency distribution curves similar in shape and crater density, whereas the lightly cratered plains on the Moon and Mars show distribution curves which, although similar to each other, are statistically different in shape and density from the more heavily cratered units. The similarities among crater size-frequency distribution curves for the Moon, Mercury, and Mars suggest that the entire inner solar system was subjected to the two populations of impacting objects but Earth and Venus have lost their record of heavy bombardment impactors. Thus, based on the cratering record on the Moon, Mercury, and Mars, it can be inferred that the Earth experienced a period of high crater rates and basin formation prior to about 3.8 BY ago. Recent studies have linked mass extinctions to large terrestrial impacts, so life forms were unable to establish themselves until impact rates decreased substantially and terrestrial conditions became more benign. The possible periodicity of mass extinctions has led to the theory of fluctuating impact rates due to comet showers in the post heavy bombardment period. The active erosional environment on the Earth complicates attempts to verify these showers by erasing geological evidence of older impact craters

  5. Chemical magnetization when determining Thellier paleointensity experiments in oceanic basalts

    Science.gov (United States)

    Tselebrovskiy, Alexey; Maksimochkin, Valery

    2017-04-01

    The natural remanent magnetization (NRM) of oceanic basalts selected in the rift zones of the Mid-Atlantic Ridge (MAR) and the Red Sea has been explored. Laboratory simulation shows that the thermoremanent magnetization and chemical remanent magnetization (CRM) in oceanic basalts may be separated by using Tellier-Coe experiment. It was found that the rate of CRM destruction is about four times lower than the rate of the partial thermoremanent magnetization formation in Thellier cycles. The blocking temperatures spectrum of chemical component shifted toward higher temperatures in comparison with the spectrum of primary thermoremanent magnetization. It was revealed that the contribution of the chemical components in the NRM increases with the age of oceanic basalts determined with the analysis of the anomalous geomagnetic field (AGF) and spreading theory. CRM is less than 10% at the basalts aged 0.2 million years, less than 50% at basalts aged 0.35 million years, from 60 to 80% at basalts aged 1 million years [1]. Geomagnetic field paleointensity (Hpl) has been determined through the remanent magnetization of basalt samples of different ages related to Brunhes, Matuyama and Gauss periods of the geomagnetic field polarity. The value of the Hpl determined by basalts of the southern segment of MAR is ranged from 17.5 to 42.5 A/m, by the Reykjanes Ridge basalts — from 20.3 to 44 A/m, by the Bouvet Ridge basalts — from 21.7 to 34.1 A/m. VADM values calculated from these data are in good agreement with the international paleointensity database [2] and PISO-1500 model [3]. Literature 1. Maksimochkin V., Tselebrovskiy A., (2015) The influence of the chemical magnetization of oceanic basalts on determining the geomagnetic field paleointensity by the thellier method, moscow university physics bulletin, 70(6):566-576, 2. Perrin, M., E. Schnepp, and V. Shcherbakov (1998), Update of the paleointensity database, Eos Trans. AGU, 79, 198. 3. Channell JET, Xuan C, Hodell DA (2009

  6. Observational constraints on the identification of shallow lunar magmatism : insights from floor-fractured craters

    OpenAIRE

    Jozwiak, Lauren; Head, James; Neumann, G. A.; Wilson, Lionel

    2017-01-01

    Floor-fractured craters are a class of lunar crater hypothesized to form in response to the emplacement of a shallow magmatic intrusion beneath the crater floor. The emplacement of a shallow magmatic body should result in a positive Bouguer anomaly relative to unaltered complex craters, a signal which is observed for the average Bouguer anomaly interior to the crater walls. We observe the Bouguer anomaly of floor-fractured craters on an individual basis using the unfiltered Bouguer gravity so...

  7. Detection of lunar floor-fractured craters using machine learning methods

    Science.gov (United States)

    Thorey, C.

    2015-10-01

    About 200 Floor Fractured Craters (FFCs) have been identified by Schultz (1976) on the Moon, mainly around the lunar maria. These craters are a class of impact craters that are distinguished by having radi-ally and concentric floor-fractured networks and ab-normally shallow floors. In some cases, the uplift of the crater floor can be as large as 50% of the initial crater depth. These impact craters are interpreted to have undergone endogenous deformations after their formation.

  8. Diversity of life in ocean floor basalt

    Science.gov (United States)

    Thorseth, I. H.; Torsvik, T.; Torsvik, V.; Daae, F. L.; Pedersen, R. B.

    2001-12-01

    Electron microscopy and biomolecular methods have been used to describe and identify microbial communities inhabiting the glassy margins of ocean floor basalts. The investigated samples were collected from a neovolcanic ridge and from older, sediment-covered lava flows in the rift valley of the Knipovich Ridge at a water depth around 3500 m and an ambient seawater temperature of -0.7°C. Successive stages from incipient microbial colonisation, to well-developed biofilms occur on fracture surfaces in the glassy margins. Observed microbial morphologies are various filamentous, coccoidal, oval, rod-shaped and stalked forms. Etch marks in the fresh glass, with form and size resembling the attached microbes, are common. Precipitation of alteration products around microbes has developed hollow subspherical and filamentous structures. These precipitates are often enriched in Fe and Mn. The presence of branching and twisted stalks that resemble those of the iron-oxidising Gallionella, indicate that reduced iron may be utilised in an energy metabolic process. Analysis of 16S-rRNA gene sequences from microbes present in the rock samples, show that the bacterial population inhabiting these samples cluster within the γ- and ɛ-Proteobacteria and the Cytophaga/Flexibacter/Bacteroides subdivision of the Bacteria, while the Archaea all belong to the Crenarchaeota kingdom. This microbial population appears to be characteristic for the rock and their closest relatives have previously been reported from cold marine waters in the Arctic and Antarctic, deep-sea sediments and hydrothermal environments.

  9. Magnesium-rich Basalts on Mercury

    Science.gov (United States)

    Martel, L. M. V.

    2013-05-01

    X-ray and gamma-ray spectrometers on NASA's MESSENGER spacecraft are making key measurements regarding the composition and properties of the surface of Mercury, allowing researchers to more clearly decipher the planet's formation and geologic history. The origin of the igneous rocks in the crust of Mercury is the focus of recent research by Karen Stockstill-Cahill and Tim McCoy (National Museum of Natural History, Smithsonian Institution), along with Larry Nittler and Shoshana Weider (Carnegie Institution of Washington) and Steven Hauck II (Case Western Reserve University). Using the well-known MELTS computer code Stockstill-Cahill and coauthors worked with MESSENGER-derived and rock-analog compositions to constrain petrologic models of the lavas that erupted on the surface of Mercury. Rock analogs included a partial melt of the Indarch meteorite and a range of Mg-rich terrestrial rocks. Their work shows the lavas on Mercury are most similar to terrestrial magnesian basalt (with lowered FeO content). The implications of the modeling are that Mg-rich lavas came from high-temperature sources in Mercury's mantle and erupted at high temperature with exceptionally low viscosity into thinly bedded and laterally extensive flows, concepts open to further evaluation by laboratory experiments and by geologic mapping of Mercury's surface using MESSENGER's imaging system and laser altimeter to document flow features and dimensions.

  10. Basalt FRP Spike Repairing of Wood Beams

    Directory of Open Access Journals (Sweden)

    Luca Righetti

    2015-08-01

    Full Text Available This article describes aspects within an experimental program aimed at improving the structural performance of cracked solid fir-wood beams repaired with Basalt Fiber Reinforced Polymer (BFRP spikes. Fir wood is characterized by its low density, low compression strength, and high level of defects, and it is likely to distort when dried and tends to fail under tension due to the presence of cracks, knots, or grain deviation. The proposed repair technique consists of the insertion of BFRP spikes into timber beams to restore the continuity of cracked sections. The experimental efforts deal with the evaluation of the bending strength and deformation properties of 24 timber beams. An artificially simulated cracking was produced by cutting the wood beams in half or notching. The obtained results for the repaired beams were compared with those of solid undamaged and damaged beams, and increases of beam capacity, bending strength and of modulus of elasticity, and analysis of failure modes was discussed. For notched beams, the application of the BFRP spikes was able to restore the original bending capacity of undamaged beams, while only a small part of the original capacity was recovered for beams that were cut in half.

  11. Radiolytic hydrogen production in the subseafloor basaltic aquifer

    Directory of Open Access Journals (Sweden)

    Mary E Dzaugis

    2016-02-01

    Full Text Available Hydrogen (H2 is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U, thorium (232Th and potassium (40K. To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt concentrations (which can vary between eruptive events and post-emplacement alteration. In our samples, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may

  12. Geochemistry of the Potassic Basalts from the Bufumbira Volcanic ...

    African Journals Online (AJOL)

    The various basalts are low in SiO2 wt %, Al2O3 wt % and Na2O wt % but high in MgO wt %, TiO2 wt %, CaO wt %, K2O wt % with K2O/Na2O = 1.08 to 2.07. These are potassic belonging to the kamafugite series. Plots discriminate two geochemical trends corresponding to the picritic and clinopyroxene rich basalts.

  13. Mechanical Characterization of Basalt and Glass Fiber Epoxy Composite Tube

    OpenAIRE

    Lapena, Mauro Henrique; Marinucci, Gerson

    2017-01-01

    The application of basalt fibers are possible in many areas thanks to its multiple and good properties. It exhibits excellent resistance to alkalis, similar to glass fiber, at a much lower cost than carbon and aramid fibers. In the present paper, a comparative study on mechanical properties of basalt and E-glass fiber composites was performed. Results of apparent hoop tensile strength test of ring specimens cut from tubes and the interlaminar shear stress (ILSS) test are presented. Tensile te...

  14. Carbon Sequestration in Olivine and Basalt Powder Packed Beds.

    Science.gov (United States)

    Xiong, Wei; Wells, Rachel K; Giammar, Daniel E

    2017-02-21

    Fractures and pores in basalt could provide substantial pore volume and surface area of reactive minerals for carbonate mineral formation in geologic carbon sequestration. In many fractures solute transport will be limited to diffusion, and opposing chemical gradients that form as a result of concentration differences can lead to spatial distribution of silicate mineral dissolution and carbonate mineral precipitation. Glass tubes packed with grains of olivine or basalt with different grain sizes and compositions were used to explore the identity and spatial distribution of carbonate minerals that form in dead-end one-dimensional diffusion-limited zones that are connected to a larger reservoir of water in equilibrium with 100 bar CO 2 at 100 °C. Magnesite formed in experiments with olivine, and Mg- and Ca-bearing siderite formed in experiments with flood basalt. The spatial distribution of carbonates varied between powder packed beds with different powder sizes. Packed beds of basalt powder with large specific surface areas sequestered more carbon per unit basalt mass than powder with low surface area. The spatial location and extent of carbonate mineral formation can influence the overall ability of fractured basalt to sequester carbon.

  15. High alkali-resistant basalt fiber for reinforcing concrete

    International Nuclear Information System (INIS)

    Lipatov, Ya.V.; Gutnikov, S.I.; Manylov, M.S.; Zhukovskaya, E.S.; Lazoryak, B.I.

    2015-01-01

    Highlights: • Doping of basalt fiber with ZrSiO 4 increased its alkali resistance. • Alkali treatment results in formation of protective surface layer on fibers. • Morphology and chemical composition of surface layer were investigated. • Mechanical properties of fibers were analyzed by a Weibull distribution. • Zirconia doped basalt fibers demonstrate high performance in concrete. - Abstract: Basalt glasses and fibers with zirconia content in the range from 0 to 7 wt% were obtained using ZrSiO 4 as a zirconium source. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. Basalt fiber with 5.7 wt% ZrO 2 had the best alkali resistance properties. Alkali treatment results in formation of protective surface layer on fibers. Morphology and chemical composition of surface layer were investigated. It was shown that alkali resistance of zirconia doped basalt fibers is caused by insoluble compounds of Zr 4+ , Fe 3+ and Mg 2+ in corrosion layer. Mechanical properties of initial and leached fibers were evaluated by a Weibull distribution. The properties of basalt fibers with ZrSiO 4 were compared with AR-glass fibers. The performance of concrete with obtained fibers was investigated

  16. Iron-Rich Carbonates as the Potential Source of Evolved CO2 Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater

    Science.gov (United States)

    Sutter, B.; Heil, E.; Rampe, E. B.; Morris, R. V.; Ming, D. W.; Archer, P. D.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; hide

    2015-01-01

    The Sample Analysis at Mars (SAM) instrument detected at least 4 distinct CO2 release during the pyrolysis of a sample scooped from the Rocknest (RN) eolian deposit. The highest peak CO2 release temperature (478-502 C) has been attributed to either a Fe-rich carbonate or nano-phase Mg-carbonate. The objective of this experimental study was to evaluate the thermal evolved gas analysis (T/EGA) characteristics of a series of terrestrial Fe-rich carbonates under analog SAM operating conditions to compare with the RN CO2 releases. Natural Fe-rich carbonates (<53 microns) with varying Fe amounts (Fe(0.66)X(0.34)- to Fe(0.99)X(0.01)-CO3, where X refers to Mg and/or Mn) were selected for T/EGA. The carbonates were heated from 25 to 715 C (35 C/min) and evolved CO2 was measured as a function of temperature. The highest Fe containing carbonates (e.g., Fe(0.99)X(0.01)-CO3) yielded CO2 peak temperatures between 466-487 C, which is consistent with the high temperature RN CO2 release. The lower Fe-bearing carbonates (e.g., Fe(0.66)X(0.34)CO3) did not have peak CO2 release temperatures that matched the RN peak CO2 temperatures; however, their entire CO2 releases did occur within RN temperature range of the high temperature CO2 release. Results from this laboratory analog analysis demonstrate that the high temperature RN CO2 release is consistent with Fe-rich carbonate (approx.0.7 to 1 wt.% FeCO3). The similar RN geochemistry with other materials in Gale Crater and elsewhere on Mars (e.g., Gusev Crater, Meridiani) suggests that up to 1 wt. % Fe-rich carbonate may occur throughout the Gale Crater region and could be widespread on Mars. The Rocknest Fe-carbonate may have formed from the interaction of reduced Fe phases (e.g., Fe2+ bearing olivine) with atmospheric CO2 and transient water. Alternatively, the Rocknest Fe-carbonate could be derived by eolian processes that have eroded distally exposed deep crustal material that possesses Fe-carbonate that may have formed through

  17. Impact cratering on porous targets in the strength regime

    Science.gov (United States)

    Nakamura, Akiko M.

    2017-12-01

    Cratering on small bodies is crucial for the collision cascade and also contributes to the ejection of dust particles into interplanetary space. A crater cavity forms against the mechanical strength of the surface, gravitational acceleration, or both. The formation of moderately sized craters that are sufficiently larger than the thickness of the regolith on small bodies, in which mechanical strength plays the dominant role rather than gravitational acceleration, is in the strength regime. The formation of microcraters on blocks on the surface is also within the strength regime. On the other hand, the formation of a crater of a size comparable to the thickness of the regolith is affected by both gravitational acceleration and cohesion between regolith particles. In this short review, we compile data from the literature pertaining to impact cratering experiments on porous targets, and summarize the ratio of spall diameter to pit diameter, the depth, diameter, and volume of the crater cavity, and the ratio of depth to diameter. Among targets with various porosities studied in the laboratory to date, based on conventional scaling laws (Holsapple and Schmidt, J. Geophys. Res., 87, 1849-1870, 1982) the cratering efficiency obtained for porous sedimentary rocks (Suzuki et al., J. Geophys. Res. 117, E08012, 2012) is intermediate. A comparison with microcraters formed on a glass target with impact velocities up to 14 km s-1 indicates a different dependence of cratering efficiency and depth-to-diameter ratio on impact velocity.

  18. Acid Sulfate Alteration on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  19. Evolution of Occator Crater on (1) Ceres

    Energy Technology Data Exchange (ETDEWEB)

    Nathues, A.; Platz, T.; Thangjam, G.; Hoffmann, M.; Corre, L. Le; Reddy, V.; Kallisch, J. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Goettingen (Germany); Mengel, K. [IELF, TU Clausthal, Adolph-Roemer-Straße 2A, 38678 Clausthal-Zellerfeld (Germany); Cloutis, E. A. [University of Winnipeg, Winnipeg, MB R3B 2E (Canada); Crown, D. A., E-mail: nathues@mps.mpg.de, E-mail: platz@mps.mpg.de, E-mail: thangjam@mps.mpg.de, E-mail: hoffmann@mps.mpg.de, E-mail: kallisch@mps.mpg.de, E-mail: gkmengel@t-online.de, E-mail: e.cloutis@uwinnipeg.ca, E-mail: lecorre@psi.edu, E-mail: reddy@psi.edu, E-mail: crown@psi.edu [Planetary Science Institute, 1700 East Fort Lowell Rd, Suite 106, Tucson, AZ 85719-2395 (United States)

    2017-03-01

    The dwarf planet Ceres (diameter 939 km) is the largest object in the main asteroid belt. Recent investigations suggest that Ceres is a thermally evolved, volatile-rich body with potential geological activity, a body which was never completely molten but possibly differentiated into a rocky core, an ice-rich mantle, and which may contain remnant internal liquid water. Thermal alteration and exogenic material infall contribute to producing a (dark) carbonaceous chondritic-like surface containing ammoniated phyllosilicates. Here we report imaging and spectroscopic analyses of Occator crater derived from the Framing Camera and the Visible and Infrared Spectrometer onboard Dawn. We found that the central bright spot (Cerealia Facula) of Occator is ∼30 Myr younger than the crater itself. The central spot is located in a central pit which contains a dome that is spectrally homogenous, exhibiting absorption features that are consistent with carbonates. Multiple radial fractures across the dome indicate an extrusive formation process. Our results lead us to conclude that the floor region was subject to past endogenic activity. Dome and bright material in its vicinity formed likely due to a long-lasting, periodic, or episodic ascent of bright material from a subsurface reservoir rich in carbonates. Originally triggered by an impact event, gases, possibly dissolved from a subsurface water/brine layer, enabled material rich in carbonates to ascend through fractures and be deposited onto the surface.

  20. Theory and experiments on centrifuge cratering

    International Nuclear Information System (INIS)

    Schmidt, R.M.; Holsapple, K.A.

    1980-01-01

    Centrifuge experimental techniques provide possibilities for laboratory simulation of ground motion and cratering effects due to explosive loadings. The results of a similarity analysis for the thermomechanical response of a continuun show that increased gravity is a necessary condition for subscale testing when identical materials for both model and prototype are being used. The general similarity requirements for this type of subscale testing are examined both theoretically and experimentally. The similarity analysis is used to derive the necessary and sufficient requirements due to the general balance and jump equations and gives relations among all the scale factors for size, density, stress, body forces, internal energy, heat supply, heat conduction, heat of detonation, and time. Additional constraints due to specific choices of material constitutive equations are evaluated separately. The class of consitutive equations that add no further requirements is identified. For this class of materials, direct simulation of large-scale cratering events at small scale on the centrifuge is possible and independent of the actual constitutive equations. For a rare-independent soil it is shown that a small experiment at gravity g and energy E is similar to a large event at 1 G but with energy equal to g 3 E. Consequently, experiments at 500 G with 8 grams of explosives can be used to

  1. Geochemistry and Geochronology of Ngorongoro Crater, Tanzania: Implication for Magma Evolution, Duration of Volcanic Activity and Age of the Ngorongoro N-R Geomagnetic Polarity Transition

    Science.gov (United States)

    Mollel, G. F.; Swisher, C. C.; Feigenson, M. D.; Carr, M. J.

    2005-05-01

    40Ar/39Ar dates on volcanic rocks from the Ngorongoro Crater (NC) in northern Tanzania indicate that NC activity was very short in duration lasting approximately 120 ka. Laser incremental heating experiments on lava from the bottom and top of the NC crater-wall section gave ages of 2.08 +/- 0.04 and 1.96 +/- 0.02 Ma respectively. Lavas from the same section show a change in magnetic polarity from normal (N) at the lower part to reverse (R) polarity at the upper part (Grommé et al. 1970). The new ages are about 400 ka younger than previously estimated by K-Ar technique. These new ages suggest correlation of the NC N-R polarity transition to the 2.1 Ma (N-R) Reunion-Matuyama boundary (Cande and Kent, 1995), instead of the Gauss-Matuyama boundary as proposed by Grommé et al. (1970). 87Sr/86Sr measurements on lavas from the NC section vary widely from 0.70801 in the trachydacite at the base to 0.70405 in the basaltic lava near the top. The lower part of the section is more radiogenic varying from 0.70592 to 0.70801 whereas the upper part is constrained to 0.70405 to 0.70450. The more radiogenic lower part is likely to have interacted with crustal rocks. Two possible contaminants are the Tanzanian Archean Craton to the west and the late Proterozoic Mozambican belt in the east. The crater-wall section is composed of trachydacite at the bottom that becomes trachyandesite in mid-section. The top section is mainly basaltic. Major and trace elements show an inverted geochemical signature that is typical of stratified magma chambers characterized by a silicic top and basaltic bottom. Olivine basalt at the upper part of the section has the highest Mg# (56.60) and in general the upper section is more mafic than the lower section as inferred from Mg#. The upper part of the section is high in TiO2, MgO, FeOT, and CaO wt% whereas SiO2 and K2O wt% are higher in lower part of the section. No significant variations are observed in N2O, Al2O3, P2O5 and MnO wt% up-section. Highly

  2. Evidence for Cyclical Fractional Crystallization, Recharge, and Assimilation in Basalts of the Kimama Core, Central Snake River Plain, Idaho: A 5.5-million-year Highlight Reel of Petrogenetic processes in a Mid-Crustal Sill Complex

    Science.gov (United States)

    Potter, Katherine E.; Shervais, John W.; Christiansen, Eric H.; Vetter, Scott K.

    2018-02-01

    Basalts erupted in the Snake River Plain of central Idaho and sampled in the Kimama drill core link eruptive processes to the construction of mafic intrusions over 5.5 Ma. Cyclic variations in basalt composition reveal temporal chemical heterogeneity related to fractional crystallization and the assimilation of previously-intruded mafic sills. A range of compositional types are identified within 1912 m of continuous drill core: Snake River olivine tholeiite (SROT), low K SROT, high Fe-Ti, and evolved and high K-Fe lavas similar to those erupted at Craters of the Moon National Monument. Detailed lithologic and geophysical logs document 432 flow units comprising 183 distinct lava flows and 78 flow groups. Each lava flow represents a single eruptive episode, while flow groups document chemically and temporally related flows that formed over extended periods of time. Temporal chemical variation demonstrates the importance of source heterogeneity and magma processing in basalt petrogenesis. Low-K SROT and high Fe-Ti basalts are genetically related to SROT as, respectively, hydrothermally-altered and fractionated daughters. Cyclic variations in the chemical composition of Kimama flow groups are apparent as 21 upward fractionation cycles, six recharge cycles, eight recharge-fractionation cycles, and five fractionation-recharge cycles. We propose that most Kimama basalt flows represent typical fractionation and recharge patterns, consistent with the repeated influx of primitive SROT parental magmas and extensive fractional crystallization coupled with varying degrees of assimilation of gabbroic to ferrodioritic sills at shallow to intermediate depths over short durations. Trace element models show that parental SROT basalts were generated by 5-10% partial melting of enriched mantle at shallow depths above the garnet-spinel lherzolite transition. The distinctive evolved and high K-Fe lavas are rare. Found at four depths, 319 m, 1045 m, 1078 m, and 1189 m, evolved and high K

  3. Mass movement on Vesta at steep scarps and crater rims

    Science.gov (United States)

    Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.; De Sanctis, M. C.; Kneissl, T.; Schmedemann, N.; Kersten, E.; Stephan, K.; Matz, K.-D.; Pieters, C. M.; Preusker, F.; Roatsch, T.; Schenk, P.; Russell, C. T.; Raymond, C. A.

    2014-12-01

    The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.

  4. Mass Movement on Vesta at Steep Scarps and Crater Rims

    Science.gov (United States)

    Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.; hide

    2014-01-01

    The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.

  5. Postshot distribution and movement of radionuclides in nuclear crater ejecta

    Energy Technology Data Exchange (ETDEWEB)

    Koranda, John J; Martin, John R; Wikkerink, Robert; Stuart, Marshall [Bio-Medical Division, Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    The distribution and postshot movement of radionuclides in nuclear crater ejecta are discussed in this report. Continuing studies of tritium movement in ejecta at SEDAN crater demonstrate that variations in tritium concentration are correlated with seasonal rainfall and soil water movements. Losses of 27 mCi H{sup 3}/ft{sup 2} are evident on SEDAN crater lip at the end of a three year period of measurements in -which an unusually large flux of rain was received. The distribution of gamma emitting radionuclides and tritium is described in the recently created SCHOONER crater ejecta field. The specific activity of radionuclides in the SCHOONER ejecta continuum is shown for ejecta collected from the crater lip to 17 miles from GZ. The movement of W{sup 181} and tritium into the sub-ejecta preshot soil is described at a site 3000 feet from GZ. (author)

  6. Acoustic fluidization and the scale dependence of impact crater morphology

    Science.gov (United States)

    Melosh, H. J.; Gaffney, E. S.

    1983-01-01

    A phenomenological Bingham plastic model has previously been shown to provide an adequate description of the collapse of impact craters. This paper demonstrates that the Bingham parameters may be derived from a model in which acoustic energy generated during excavation fluidizes the rock debris surrounding the crater. Experimental support for the theoretical flow law is presented. Although the Bingham yield stress cannot be computed without detailed knowledge of the initial acoustic field, the Bingham viscosity is derived from a simple argument which shows that it increases as the 3/2 power of crater diameter, consistent with observation. Crater collapse may occur in material with internal dissipation Q as low as 100, comparable to laboratory observations of dissipation in granular materials. Crater collapse thus does not require that the acoustic field be regenerated during flow.

  7. Icelandic basaltic geothermal field: A natural analog for nuclear waste isolation in basalt

    International Nuclear Information System (INIS)

    Ulmer, G.C.; Grandstaff, D.E.

    1984-01-01

    Analog studies of Icelandic geothermal fields have shown that the design of nuclear waste repositories in basalt can benefit by comparison to the data base already available from the development of these geothermal fields. A high degree of similarity exists between these two systems: their petrology, groundwater geochemistry, mineral solubilities, hydrologic parameters, temperature ranges, water-rock redox equilibria, hydrothermal pH values, and secondary mineralogies all show considerable overlap in the range of values. The experimentally-simulated hydrothermal studies of the basaltic nuclear waste repository rocks have, at this time, produced a data base that receives a strong confirmation from the Icelandic analog. Furthermore, the Icelandic analog should eventually be employed to extrapolate into higher and lower temperatures, into longer time-base chemical comparisons, and into more realistic mineral deposition studies, than have been possible in the laboratory evaluations of the nuclear waste repository designs. This eventual use of the Icelandic analog will require cooperative work with the Icelandic Geological Survey. 46 refs., 4 figs., 2 tabs

  8. Simple Impact Crater Shapes From Shadows - The Sequel

    Science.gov (United States)

    Chappelow, J. E.

    2008-12-01

    At the last LPSC meeting I presented the outline of a method for determining simple impact crater shapes from shadows. In theory the shadow cast within a simple crater provides enough information to derive its cross-sectional shape from shadow measurements, at least to the maximum depth to which the shadow extends. Under certain simple assumptions, this can be done analytically. If the crater is conic-section - shaped, then it can be shown that the down-sun bound of any shadow cast within it is elliptical, with one axis along the direction of illumination and the other (perpendicular to it) of semi-length D/2 (where D is diameter). The properties of this shadow-ellipse can be related to the parameters of the crater shape conic-section, thus measurements of the shadow-ellipse yield not only crater depth and diameter but also the approximate crater shape, in terms of conic sections. The method also does not depend upon the shadow crossing near the crater center, which avoids a pitfall of older shadow measurement methods. The technique is also amenable to computer implementation, which has already been largely completed. Once computerized, crater measurements can be made rapidly and repeatably. The program reads in an image, its resolution, and the solar elevation and azimuth. The user then defines the crater rim by 'clicking' on three points, and the shadow ellipse by clicking on two more. The program calculates and outputs the diameter, the depth, and parameters describing the crater's approximating conic-section. It is highly applicable to situations where only single-image photography is available, for example MESSENGER flybys of Mercury. At the meeting I will present the finished math for this method and give some examples of its use.

  9. LU60645GT and MA132843GT Catalogues of Lunar and Martian Impact Craters Developed Using a Crater Shape-based Interpolation Crater Detection Algorithm for Topography Data

    Science.gov (United States)

    Salamuniccar, Goran; Loncaric, Sven; Mazarico, Erwan Matias

    2012-01-01

    For Mars, 57,633 craters from the manually assembled catalogues and 72,668 additional craters identified using several crater detection algorithms (CDAs) have been merged into the MA130301GT catalogue. By contrast, for the Moon the most complete previous catalogue contains only 14,923 craters. Two recent missions provided higher-quality digital elevation maps (DEMs): SELENE (in 1/16° resolution) and Lunar Reconnaissance Orbiter (we used up to 1/512°). This was the main motivation for work on the new Crater Shape-based interpolation module, which improves previous CDA as follows: (1) it decreases the number of false-detections for the required number of true detections; (2) it improves detection capabilities for very small craters; and (3) it provides more accurate automated measurements of craters' properties. The results are: (1) LU60645GT, which is currently the most complete (up to D>=8 km) catalogue of Lunar craters; and (2) MA132843GT catalogue of Martian craters complete up to D>=2 km, which is the extension of the previous MA130301GT catalogue. As previously achieved for Mars, LU60645GT provides all properties that were provided by the previous Lunar catalogues, plus: (1) correlation between morphological descriptors from used catalogues; (2) correlation between manually assigned attributes and automated measurements; (3) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc; and (4) a review of positional accuracy of used datasets. Additionally, surface dating could potentially be improved with the exhaustiveness of this new catalogue. The accompanying results are: (1) the possibility of comparing a large number of Lunar and Martian craters, of e.g. depth/diameter ratio and 2D profiles; (2) utilisation of a method for re-projection of datasets and catalogues, which is very useful for craters that are very close to poles; and (3) the extension of the

  10. Geomechanical rock properties of a basaltic volcano

    Directory of Open Access Journals (Sweden)

    Lauren N Schaefer

    2015-06-01

    Full Text Available In volcanic regions, reliable estimates of mechanical properties for specific volcanic events such as cyclic inflation-deflation cycles by magmatic intrusions, thermal stressing, and high temperatures are crucial for building accurate models of volcanic phenomena. This study focuses on the challenge of characterizing volcanic materials for the numerical analyses of such events. To do this, we evaluated the physical (porosity, permeability and mechanical (strength properties of basaltic rocks at Pacaya Volcano (Guatemala through a variety of laboratory experiments, including: room temperature, high temperature (935 °C, and cyclically-loaded uniaxial compressive strength tests on as-collected and thermally-treated rock samples. Knowledge of the material response to such varied stressing conditions is necessary to analyze potential hazards at Pacaya, whose persistent activity has led to 13 evacuations of towns near the volcano since 1987. The rocks show a non-linear relationship between permeability and porosity, which relates to the importance of the crack network connecting the vesicles in these rocks. Here we show that strength not only decreases with porosity and permeability, but also with prolonged stressing (i.e., at lower strain rates and upon cooling. Complimentary tests in which cyclic episodes of thermal or load stressing showed no systematic weakening of the material on the scale of our experiments. Most importantly, we show the extremely heterogeneous nature of volcanic edifices that arise from differences in porosity and permeability of the local lithologies, the limited lateral extent of lava flows, and the scars of previous collapse events. Input of these process-specific rock behaviors into slope stability and deformation models can change the resultant hazard analysis. We anticipate that an increased parameterization of rock properties will improve mitigation power.

  11. Creation of High Resolution Terrain Models of Barringer Meteorite Crater (Meteor Crater) Using Photogrammetry and Terrestrial Laser Scanning Methods

    Science.gov (United States)

    Brown, Richard B.; Navard, Andrew R.; Holland, Donald E.; McKellip, Rodney D.; Brannon, David P.

    2010-01-01

    Barringer Meteorite Crater or Meteor Crater, AZ, has been a site of high interest for lunar and Mars analog crater and terrain studies since the early days of the Apollo-Saturn program. It continues to be a site of exceptional interest to lunar, Mars, and other planetary crater and impact analog studies because of its relatively young age (est. 50 thousand years) and well-preserved structure. High resolution (2 meter to 1 decimeter) digital terrain models of Meteor Crater in whole or in part were created at NASA Stennis Space Center to support several lunar surface analog modeling activities using photogrammetric and ground based laser scanning techniques. The dataset created by this activity provides new and highly accurate 3D models of the inside slope of the crater as well as the downslope rock distribution of the western ejecta field. The data are presented to the science community for possible use in furthering studies of Meteor Crater and impact craters in general as well as its current near term lunar exploration use in providing a beneficial test model for lunar surface analog modeling and surface operation studies.

  12. Snow-avalanche impact craters in southern Norway: Their morphology and dynamics compared with small terrestrial meteorite craters

    Science.gov (United States)

    Matthews, John A.; Owen, Geraint; McEwen, Lindsey J.; Shakesby, Richard A.; Hill, Jennifer L.; Vater, Amber E.; Ratcliffe, Anna C.

    2017-11-01

    This regional inventory and study of a globally uncommon landform type reveals similarities in form and process between craters produced by snow-avalanche and meteorite impacts. Fifty-two snow-avalanche impact craters (mean diameter 85 m, range 10-185 m) were investigated through field research, aerial photographic interpretation and analysis of topographic maps. The craters are sited on valley bottoms or lake margins at the foot of steep avalanche paths (α = 28-59°), generally with an easterly aspect, where the slope of the final 200 m of the avalanche path (β) typically exceeds 15°. Crater diameter correlates with the area of the avalanche start zone, which points to snow-avalanche volume as the main control on crater size. Proximal erosional scars ('blast zones') up to 40 m high indicate up-range ejection of material from the crater, assisted by air-launch of the avalanches and impulse waves generated by their impact into water-filled craters. Formation of distal mounds up to 12 m high of variable shape is favoured by more dispersed down-range deposition of ejecta. Key to the development of snow-avalanche impact craters is the repeated occurrence of topographically-focused snow avalanches that impact with a steep angle on unconsolidated sediment. Secondary craters or pits, a few metres in diameter, are attributed to the impact of individual boulders or smaller bodies of snow ejected from the main avalanche. The process of crater formation by low-density, low-velocity, large-volume snow flows occurring as multiple events is broadly comparable with cratering by single-event, high-density, high-velocity, small-volume projectiles such as small meteorites. Simple comparative modelling of snow-avalanche events associated with a crater of average size (diameter 85 m) indicates that the kinetic energy of a single snow-avalanche impact event is two orders of magnitude less than that of a single meteorite-impact event capable of producing a crater of similar size

  13. Complex layering of the Orange Mountain Basalt: New Jersey, USA

    Science.gov (United States)

    Puffer, John H.; Block, Karin A.; Steiner, Jeffrey C.; Laskowich, Chris

    2018-06-01

    The Orange Mountain Basalt of New Jersey is a Mesozoic formation consisting of three units: a single lower inflated sheet lobe about 70 m thick (OMB1), a middle pillow basalt about 10 to 20 m thick (OMB2), and an upper compound pahoehoe flow about 20 to 40 m thick (OMB3). The Orange Mountain Basalt is part of the Central Atlantic Magmatic Province. Quarry and road-cut exposures of OMB1 near Paterson, New Jersey, display some unusual layering that is the focus of this study. OMB1 exposures displays the typical upper crust, core, and basal crust layers of sheet lobes but throughout the Patterson area also display distinct light gray layers of microvesicular basalt mineralized with albite directly over the basal crust and under the upper crust. The lower microvesicular layer is associated with mega-vesicular diapirs. We propose that the upper and lower microvesicular layers were composed of viscous crust that was suddenly quenched before it could devolatilize immediately before the solidification of the core. During initial cooling, the bottom of the basal layer was mineralized with high concentrations of calcite and albite during a high-temperature hydrothermal event. Subsequent albitization, as well as zeolite, prehnite, and calcite precipitation events, occurred during burial and circulation of basin brine heated by recurring Palisades magmatism below the Orange Mountain Basalt. Some of the events experienced by the Orange Mountain Basalt are unusual and place constraints on the fluid dynamics of thick flood basalt flows in general. The late penetration of vesicular diapirs through the entire thickness of the flow interior constrains its viscosity and solidification history.

  14. Surface oxidization-reduction reactions in Columbia Plateau basalts

    International Nuclear Information System (INIS)

    White, A.F.; Yee, A.

    1984-01-01

    Results are presented which define principal oxidation-reduction reactions expected between ground water and iron in the Umtanum and Cohassett basalt flows of south central Washington. Data include kinetics of aqueous iron speciation, rates of O 2 uptake and nature of oxyhydroxide precipitates. Such data are important in predicting behavior of radionuclides in basalt aquifers including determination of valence states, speciation, solubility, sorption, and coprecipitation on iron oxyhydroxide substrates and colloids. Analyses of the basalt by XPS indicates that ferrous iron is oxidized to ferric iron on the surface and that the total iron decreases as a function of pH during experimental weathering. Iron oxyhydroxide phases did not form surface coating on basalt surfaces but rather nucleated as separate plases in solution. No significant increases in Cs or Sr sorption were observed with increased weathering of the basalt. Concurrent increases in Fe(II) and decreases in Fe(III) in slightly to moderately acid solutions indicated continued oxidization of ferrous iron in the basalt. At neutral to basic pH, Fe(II) was strongly sorbed onto the basalt surface (Kd = 6.5 x 10 -3 1 x m 2 ) resulting in low dissolved concentrations even under anoxic conditions. The rate of O 2 uptake increased with decreasing pH. Diffusion rates (-- 10 -14 cm 2 x s -1 ), calculated using a one-dimensional analytical model, indicate grain boundary diffusion. Comparisons of Eh values calculated by Pt electrode, dissolved O 2 and Fe(II)/Fe(III) measurements showed considerable divergence, with the ferric-ferrous couple being the preferred method of estimating Eh

  15. Evidence for biological activity in mineralization of secondary sulphate deposits in a basaltic environment: implications for the search for life in the Martian subsurface

    Science.gov (United States)

    Richardson, C. Doc; Hinman, Nancy W.; Scott, Jill R.

    2013-10-01

    Evidence of microbial activity associated with mineralization of secondary Na-sulphate minerals (thenardite, mirabilite) in the basaltic subsurface of Craters of the Moon National Monument (COM), Idaho were examined by scanning electron microscopy, X-ray diffraction, laser desorption Fourier transform ion cyclotron resonance mass spectrometry (LD-FTICR-MS), Fourier transform infrared spectroscopy (FTIR) and isotope ratio mass spectrometry. Peaks suggestive of bio/organic compounds were observed in the secondary Na-sulphate deposits by LD-FTICR-MS. FTIR provided additional evidence for the presence of bio/organic compounds. Sulphur fractionation was explored to assist in determining if microbes may play a role in oxidizing sulphur. The presence of bio/organic compounds associated with Na-sulphate deposits, along with the necessity of oxidizing reduced sulphur to sulphate, suggests that biological activity may be involved in the formation of these secondary minerals. The secondary Na-sulphate minerals probably form from the overlying basalt through leached sodium ions and sulphate ions produced by bio-oxidation of Fe-sulphide minerals. Since the COM basalts are one of the most comparable terrestrial analogues for their Martian counterparts, the occurrence of biological activity in the formation of sulphate minerals at COM has direct implications for the search for life on Mars. In addition, the presence of caves on Mars suggests the importance of these environments as possible locations for growth and preservation of microbial activity. Therefore, understanding the physiochemical pathways of abiotic and biotic mineralization in the COM subsurface and similar basaltic settings has direct implications for the search for extinct or extant life on Mars.

  16. Preliminary Hydrogeologic Characterization Results from the Wallula Basalt Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    B.P. McGrail; E. C. Sullivan; F. A. Spane; D. H. Bacon; G. Hund; P. D. Thorne; C. J. Thompson; S. P. Reidel; F. S. Colwell

    2009-12-01

    The DOE's Big Sky Regional Carbon Sequestration Partnership has completed drilling the first continental flood basalt sequestration pilot borehole to a total depth (TD) of 4,110 feet on the Boise White Paper Mill property at Wallula, Washington. Site suitability was assessed prior to drilling by the 2007-2008 acquisition, processing and analysis of a four-mile, five-line three component seismic swath, which was processed as a single data-dense line. Analysis of the seismic survey data indicated a composite basalt formation thickness of {approx}8,000 feet and absence of major geologic structures (i.e., faults) along the line imaged by the seismic swath. Drilling of Wallula pilot borehole was initiated on January 13, 2009 and reached TD on April 6, 2009. Based on characterization results obtained during drilling, three basalt breccia zones were identified between the depth interval of 2,716 and 2,910 feet, as being suitable injection reservoir for a subsequent CO2 injection pilot study. The targeted injection reservoir lies stratigraphically below the massive Umtanum Member of the Grande Ronde Basalt, whose flow-interior section possesses regionally recognized low-permeability characteristics. The identified composite injection zone reservoir provides a unique and attractive opportunity to scientifically study the reservoir behavior of three inter-connected reservoir intervals below primary and secondary caprock confining zones. Drill cuttings, wireline geophysical logs, and 31one-inch diameter rotary sidewall cores provided geologic data for characterization of rock properties. XRF analyses of selected rock samples provided geochemical characterizations of the rocks and stratigraphic control for the basalt flows encountered by the Wallula pilot borehole. Based on the geochemical results, the pilot borehole was terminated in the Wapshilla Ridge 1 flow of the Grande Ronde Basalt Formation. Detailed hydrologic test characterizations of 12 basalt interflow

  17. Ancient aqueous environments at Endeavour crater, Mars

    Science.gov (United States)

    Arvidson, R. E.; Squyres, S. W.; Bell, J.F.; Catalano, J.G.; Clark, B. C.; Crumpler, L.S.; de Souza, P.A.; Fairén, A.G.; Farrand, W. H.; Fox, V.K.; Gellert, Ralf; Ghosh, A.; Golombeck, M.P.; Grotzinger, J.P.; Guinness, E.A.; Herkenhoff, Kenneth E.; Jolliff, B.L.; Knoll, A.H.; Li, R.; McLennan, S.M.; Ming, D. W.; Mittlefehldt, D. W.; Moore, Johnnie N.; Morris, R.V.; Murchie, S.L.; Parker, T.J.; Paulsen, G.; Rice, J.W.; Ruff, S.W.; Smith, M.D.; Wolff, M.J.

    2014-01-01

    Opportunity has investigated in detail rocks on the rim of the Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate the presence of Fe+3-rich smectites. The signatures are associated with fine-grained, layered rocks containing spherules of diagenetic or impact origin. The layered rocks are overlain by breccias, and both units are cut by calcium sulfate veins precipitated from fluids that circulated after the Endeavour impact. Compositional data for fractures in the layered rocks suggest formation of Al-rich smectites by aqueous leaching. Evidence is thus preserved for water-rock interactions before and after the impact, with aqueous environments of slightly acidic to circum-neutral pH that would have been more favorable for prebiotic chemistry and microorganisms than those recorded by younger sulfate-rich rocks at Meridiani Planum.

  18. Martian Fluvial Conglomerates at Gale Crater

    Science.gov (United States)

    Williams, R. M. E.; Grotzinger, J. P.; Dietrich, W. E.; Gupta, S.; Sumner, D. Y.; Wiens, R. C.; Mangold, N.; Malin, M. C.; Edgett, K. S.; Maurice, S.; Forni, O.; Gasnault, O.; Ollila, A.; Newsom, H. E.; Dromart, G.; Palucis, M. C.; Yingst, R. A.; Anderson, R. B.; Herkenhoff, K. E.; Le Mouélic, S.; Goetz, W.; Madsen, M. B.; Koefoed, A.; Jensen, J. K.; Bridges, J. C.; Schwenzer, S. P.; Lewis, K. W.; Stack, K. M.; Rubin, D.; Kah, L. C.; Bell, J. F.; Farmer, J. D.; Sullivan, R.; Van Beek, T.; Blaney, D. L.; Pariser, O.; Deen, R. G.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Edgar, Lauren; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sobrón Sánchez, Pablo; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Aparicio, Carlos Armiens; Caride Rodríguez, Javier; Carrasco Blázquez, Isaías; Gómez Gómez, Felipe; Elvira, Javier Gómez; Hettrich, Sebastian; Lepinette Malvitte, Alain; Marín Jiménez, Mercedes; Frías, Jesús Martínez; Soler, Javier Martín; Torres, F. Javier Martín; Molina Jurado, Antonio; Sotomayor, Luis Mora; Muñoz Caro, Guillermo; Navarro López, Sara; González, Verónica Peinado; García, Jorge Pla; Rodriguez Manfredi, José Antonio; Planelló, Julio José Romeral; Alejandra Sans Fuentes, Sara; Sebastian Martinez, Eduardo; Torres Redondo, Josefina; O'Callaghan, Roser Urqui; Zorzano Mier, María-Paz; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; Uston, Claude d.; Lasue, Jérémie; Lee, Qiu-Mei; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Szopa, Cyril; Robert, François; Sautter, Violaine; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; de la Torre Juarez, Manuel; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Blanco Ávalos, Juan José; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; González, Rafael Navarro; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Kortmann, Onno; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Jakosky, Bruce; Zunic, Tonci Balic; Frydenvang, Jens; Kinch, Kjartan; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mellin, Reinhold Mueller; Schweingruber, Robert Wimmer; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2013-05-01

    Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

  19. The Microstructure of Lunar Micrometeorite Impact Craters

    Science.gov (United States)

    Noble, S. K.; Keller, L. P.; Christoffersen, R.; Rahman, Z.

    2016-01-01

    The peak of the mass flux of impactors striking the lunar surface is made up of objects approximately 200 micrometers in diameter that erode rocks, comminute regolith grains, and produce agglutinates. The effects of these micro-scale impacts are still not fully understood. Much effort has focused on evaluating the physical and optical effects of micrometeorite impacts on lunar and meteoritic material using pulsed lasers to simulate the energy deposited into a substrate in a typical hypervelocity impact. Here we characterize the physical and chemical changes that accompany natural micrometeorite impacts into lunar rocks with long surface exposure to the space environment (12075 and 76015). Transmission electron microscope (TEM) observations were obtained from cross-sections of approximately 10-20 micrometers diameter craters that revealed important micro-structural details of micrometeorite impact processes, including the creation of npFe (sup 0) in the melt, and extensive deformation around the impact site.

  20. Slope activity in Gale crater, Mars

    Science.gov (United States)

    Dundas, Colin M.; McEwen, Alfred S.

    2015-01-01

    High-resolution repeat imaging of Aeolis Mons, the central mound in Gale crater, reveals active slope processes within tens of kilometers of the Curiosity rover. At one location near the base of northeastern Aeolis Mons, dozens of transient narrow lineae were observed, resembling features (Recurring Slope Lineae) that are potentially due to liquid water. However, the lineae faded and have not recurred in subsequent Mars years. Other small-scale slope activity is common, but has different spatial and temporal characteristics. We have not identified confirmed RSL, which Rummel et al. (Rummel, J.D. et al. [2014]. Astrobiology 14, 887–968) recommended be treated as potential special regions for planetary protection. Repeat images acquired as Curiosity approaches the base of Aeolis Mons could detect changes due to active slope processes, which could enable the rover to examine recently exposed material.

  1. Crater Topography on Titan: Implications for Landscape Evolution

    Science.gov (United States)

    Neish, Catherine D.; Kirk, R.L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.

    2013-01-01

    We present a comprehensive review of available crater topography measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 +/- 0.0003 (for the largest crater studied, Menrva, D approximately 425 km) and 0.017 +/- 0.004 (for the smallest crater studied, Ksa, D approximately 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.

  2. Noachian and more recent phyllosilicates in impact craters on Mars.

    Science.gov (United States)

    Fairén, Alberto G; Chevrier, Vincent; Abramov, Oleg; Marzo, Giuseppe A; Gavin, Patricia; Davila, Alfonso F; Tornabene, Livio L; Bishop, Janice L; Roush, Ted L; Gross, Christoph; Kneissl, Thomas; Uceda, Esther R; Dohm, James M; Schulze-Makuch, Dirk; Rodríguez, J Alexis P; Amils, Ricardo; McKay, Christopher P

    2010-07-06

    Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.

  3. The Morphology of Craters on Mercury: Results from MESSENGER Flybys

    Science.gov (United States)

    Barnouin, Oliver S.; Zuber, Maria T.; Smith, David E.; Neumann, Gregory A.; Herrick, Robert R.; Chappelow, John E.; Murchie, Scott L.; Prockter, Louise M.

    2012-01-01

    Topographic data measured from the Mercury Laser Altimeter (MLA) and the Mercury Dual Imaging System (MDIS) aboard the MESSENGER spacecraft were used for investigations of the relationship between depth and diameter for impact craters on Mercury. Results using data from the MESSENGER flybys of the innermost planet indicate that most of the craters measured with MLA are shallower than those previously measured by using Mariner 10 images. MDIS images of these same MLA-measured craters show that they have been modified. The use of shadow measurement techniques, which were found to be accurate relative to the MLA results, indicate that both small bowl-shaped and large complex craters that are fresh possess depth-to-diameter ratios that are in good agreement with those measured from Mariner 10 images. The preliminary data also show that the depths of modified craters are shallower relative to fresh ones, and might provide quantitative estimates of crater in-filling by subsequent volcanic or impact processes. The diameter that defines the transition from simple to complex craters on Mercury based on MESSENGER data is consistent with that reported from Mariner 10 data.

  4. Diffusion of hydrous species in model basaltic melt

    Science.gov (United States)

    Zhang, Li; Guo, Xuan; Wang, Qinxia; Ding, Jiale; Ni, Huaiwei

    2017-10-01

    Water diffusion in Fe-free model basaltic melt with up to 2 wt% H2O was investigated at 1658-1846 K and 1 GPa in piston-cylinder apparatus using both hydration and diffusion couple techniques. Diffusion profiles measured by FTIR are consistent with a model in which both molecular H2O (H2Om) and hydroxyl (OH) contribute to water diffusion. OH diffusivity is roughly 13% of H2Om diffusivity, showing little dependence on temperature or water concentration. Water diffusion is dominated by the motion of OH until total H2O (H2Ot) concentration reaches 1 wt%. The dependence of apparent H2Ot diffusivity on H2Ot concentration appears to be overestimated by a previous study on MORB melt, but H2Ot diffusivity at 1 wt% H2Ot in basaltic melt is still greater than those in rhyolitic to andesitic melts. The appreciable contribution of OH to water diffusion in basaltic melt can be explained by enhanced mobility of OH, probably associated with the development of free hydroxyl bonded with network-modifying cations, as well as higher OH concentration. Calculation based on the Nernst-Einstein equation demonstrates that OH may serve as an effective charge carrier in hydrous basaltic melt, which could partly account for the previously observed strong influence of water on electrical conductivity of basaltic melt.

  5. Stratigraphy of Oceanus Procellarum basalts - Sources and styles of emplacement

    Science.gov (United States)

    Whitford-Stark, J. L.; Head, J. W., III

    1980-01-01

    The basaltic fill of Oceanus Procellarum has been formally subdivided into four lithostratigraphic formations: The Repsold Formation, the Telemann Formation, the Hermann Formation, and the Sharp Formation. The Repsold Formation is composed of high-Ti basalts and pyroclastic deposits with an estimated age of 3.75 + or - 0.05 b.y. and an estimated volume of about 2.1 x 10 to the 5th cu km. This is overlain by the Telemann Formation composed of very low-Ti basalts and pyroclastic deposits with an estimated age of 3.6 + or - 0.2 b.y. and a volume of 4.2 x 10 to the 5th cu km. The Hermann Formation, composed of intermediate basalts with an estimated age of 3.3 + or - 0.3 b.y., represents the next youngest unit with an estimated volume of 2.2 x 10 to the 5th cu km. The youngest materials in Procellarum are the medium-to-high-Ti basalts comprising the Sharp Formation with an estimated age of 2.7 + or - 0.7 b.y. and a volume of 1.8 x 10 to the 4th cu km.

  6. Similar microbial communities found on two distant seafloor basalts

    Directory of Open Access Journals (Sweden)

    Esther eSinger

    2015-12-01

    Full Text Available The oceanic crust forms two thirds of the Earth’s surface and hosts a large phylogenetic and functional diversity of microorganisms. While advances have been made in the sedimentary realm, our understanding of the igneous rock portion as a microbial habitat has remained limited. We present the first comparative metagenomic microbial community analysis from ocean floor basalt environments at the Lō’ihi Seamount, Hawai’i, and the East Pacific Rise (EPR (9˚N. Phylogenetic analysis indicates the presence of a total of 43 bacterial and archaeal mono-phyletic groups, dominated by Alpha- and Gammaproteobacteria, as well as Thaumarchaeota. Functional gene analysis suggests that these Thaumarchaeota play an important role in ammonium oxidation on seafloor basalts. In addition to ammonium oxidation, the seafloor basalt habitat reveals a wide spectrum of other metabolic potentials, including CO2 fixation, denitrification, dissimilatory sulfate reduction, and sulfur oxidation. Basalt communities from Lō’ihi and the EPR show considerable metabolic and phylogenetic overlap down to the genus level despite geographic distance and slightly different seafloor basalt mineralogy.

  7. Chemical hazards from acid crater lakes

    Science.gov (United States)

    van Bergen, M. J.; Sumarti, S.; Heikens, A.; Bogaard, T. A.; Hartiyatun, S.

    2003-04-01

    Acid crater lakes, which are hosted by a considerable number of active volcanoes, form a potential threat for local ecosystems and human health, as they commonly contain large amounts of dissolved chemicals. Subsurface seepage or overflow can lead to severe deterioration of the water quality of rivers and wells, as observations around several of these volcanoes have shown. The Ijen crater lake in East Java (Indonesia) is a striking example, as this reservoir of hyperacid (pHfluoride-rich water is the source of a ca. 50 km long acid river that transports substantial quantities of potentially toxic elements. A downstream trend of increasing pH from fluoride levels pose some of the most severe environmental threats. Its concentration decreases from ca. 1300 mg/kg in the lake to ca. 10 mg/kg in a coastal area downstream, where virtually all of the river water is used for irrigating rice fields and other cropland. Apart from serious problems for agriculture, our survey of 55 drinking water wells in the irrigation area shows that 50% contain fluoride above the 1.5 ppm WHO limit, in line with the observation that dental fluorosis is widespread among the ca. 100,000 residents of the area. A conspicuous spatial correlation between fluoride concentrations and the irrigation system suggest that long-term (century) infiltration of irrigation water may have affected the quality of groundwater. Fluorosis is also a problem in some villages within the caldera, where well water sources may have a more direct subsurface connection with the lake system. From our observations we conclude that water-quality monitoring is especially needed for health reasons in volcanic areas where volatile elements, derived from passively degassing magma, are intercepted by (sub) surface water bodies.

  8. Rock spatial densities on the rims of the Tycho secondary craters in Mare Nectaris

    Science.gov (United States)

    Basilevsky, A. T.; Michael, G. G.; Kozlova, N. A.

    2018-04-01

    The aim of this work is to check whether the technique of estimation of age of small lunar craters based on spatial density of rock boulders on their rims described in Basilevsky et al. (2013, 2015b) and Li et al. (2017) for the craters rock counts on the rims of four craters having diameters 1000, 1100, 1240 and 1400 m located in Mare Nectaris. These craters are secondaries of the primary crater Tycho, whose age was found to be 109 ± 4 Ma (Stoffler and Ryder, 2001) so this may be taken as the age of the four craters, too. Using the dependence of the rock spatial densities at the crater rims on the crater age for the case of mare craters (Li et al., 2017) our measured rock densities correspond to ages from ∼100 to 130 Ma. These estimates are reasonably close to the given age of the primary crater Tycho. This, in turn, suggests that this technique of crater age estimation is applicable to craters up to ∼1.5 km in diameter. For the four considered craters we also measured their depth/diameter ratios and the maximum angles of the crater inner slopes. For the considered craters it was found that with increasing crater diameter, the depth/diameter ratios and maximum angles of internal slopes increase, but the values of these parameters for specific craters may deviate significantly from the general trends. The deviations probably result from some dissimilarities in the primary crater geometries, that may be due to crater to crater differences in characteristics of impactors (e.g., in their bulk densities) and/or differences in the mechanical properties of the target. It may be possible to find secondaries of crater Tycho in the South pole area and, if so, they may be studied to check the specifics and rates of the rock boulder degradation in the lunar polar environment.

  9. The Mineralogical and Chemical Case for Habitability at Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    Blake, David Frederick; Vaniman, David; Grotzinger, John P.; Conrad, Pamela Gales; Ming, Douglas W.; Bish, David L.; Farmer, Jack D.; Bristow, Thomas

    2013-01-01

    Sediments of the Yellowknife Bay formation (Gale crater) include the Sheepbed member, a mudstone cut by light-toned veins. Two drill samples, John Klein and Cumberland, were collected and analyzed by the CheMin XRD/XRF instrument and the Sample Analysis at Mars (SAM) evolved gas and isotopic analysis suite of instruments. Drill cuttings were also analyzed by the Alpha Particle X-ray Spectrometer (APXS) for bulk composition. The CheMin XRD analysis shows that the mudstone contains basaltic minerals (Fe-forsterite, augite, pigeonite, plagioclase), as well as Fe-oxide/hydroxides, Fe-sulfides, amorphous materials, and trioctahedral phyllosilicates. SAM evolved gas analysis of higher-temperature OH matches the CheMin XRD estimate of 20% clay minerals in the mudstone. The light-toned veins contain Ca-sulfates; anhydrite and bassanite are detected by XRD but gypsum is also indicated from Mastcam spectral mapping. These sulfates appear to be almost entirely restricted to late-diagenetic veins. The sulfate content of the mudstone matrix itself is lower than other sediments analyzed on Mars. The presence of phyllosilicates indicates that the activity of water was high during their formation and/or transport and deposition (should they have been detrital). Lack of chlorite places limits on the maximum temperature of alteration (likely habitable environment: Aqueous deposition at clement conditions of P, T, pH, Eh and ionic strength, plus the availability of sources of chemical energy.

  10. Prediction of gamma exposure rates in large nuclear craters

    Energy Technology Data Exchange (ETDEWEB)

    Tami, Thomas M; Day, Walter C [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)

    1970-05-15

    In many civil engineering applications of nuclear explosives there is the need to reenter the crater and lip area as soon as possible after the detonation to carry out conventional construction activities. These construction activities, however, must be delayed until the gamma dose rate, or exposure rate, in and around the crater decays to acceptable levels. To estimate the time of reentry for post-detonation construction activities, the exposure rate in the crater and lip areas must be predicted as a function of time after detonation. An accurate prediction permits a project planner to effectively schedule post-detonation activities.

  11. Morphometry and Morphology of Fresh Craters on Titan

    Science.gov (United States)

    Kirk, R. L.; Wood, C. A.; Neish, C.; Lucas, A.; Hayes, A. G.; Cassini Radar Team

    2011-12-01

    Cassini RADAR imagery obtained on Titan flyby T77 revealed a 40-km diameter fresh impact crater at 11.6° N 44.6° W. This is only the 8th crater identified with high confidence (Wood et al., 2010, Icarus 206, 334), and the 3rd (after Sinlap D=79 km and Ksa D=30 km) for which the depth can be estimated by comparing the foreshortening of the near and far walls. This "autostereo" technique yields an estimated depth of 680 m. The T77 image forms a stereo pair with the T17 discovery image of Ksa from which we estimate the depth of Ksa at 750-800 m, in close agreement with SARTopo data. The depth of Sinlap is 760 m based on SARTopo. Depth-diameter ratios for these craters thus range from 0.01 to 0.025 and the depths are comparable to but 200-400 m shallower than fresh craters of the same size on Ganymede (Bray et al., 2008, Met. Planet Sci. 43, 1979). The depth differences could be explained by initial crater morphometry, by relaxation in a different thermal environment, or (perhaps most plausibly given the bland floors of even the freshest Titan craters) to sedimentary infill. In contrast, the 18x36 km elliptical depression at Sotra Facula is much deeper than Ganymede craters of similar size (d=1500 m from stereo), supporting the conclusion that it is not an impact crater. All three craters exhibit a relatively radar-bright annulus around the outer edge of the floor, possibly as the result of mass wasting of blocky materials from the crater walls. The central part of each crater is darker. The central darker floor of the new crater is symmetrical and featureless, whereas Ksa has a bright central ring 7 km in diameter. Stereo spot heights indicate the ring is 350±100 m above the outer floor. This height is in close agreement with the scaling for Ganymede crater central peaks from Bray et al. (2008). The darker floor area of Sinlap is substantially asymmetrical with a small bright central spot whose elevation is unknown. The new crater has continuous, radar

  12. High water content in primitive continental flood basalts.

    Science.gov (United States)

    Xia, Qun-Ke; Bi, Yao; Li, Pei; Tian, Wei; Wei, Xun; Chen, Han-Lin

    2016-05-04

    As the main constituent of large igneous provinces, the generation of continental flood basalts (CFB) that are characterized by huge eruption volume (>10(5) km(3)) within short time span (primitive CFB in the early Permian Tarim large igneous province (NW China), using the H2O content of ten early-formed clinopyroxene (cpx) crystals that recorded the composition of the primitive Tarim basaltic melts and the partition coefficient of H2O between cpx and basaltic melt. The arc-like H2O content (4.82 ± 1.00 wt.%) provides the first clear evidence that H2O plays an important role in the generation of CFB.

  13. Corrosion phase formation on container alloys in basalt repository environments

    International Nuclear Information System (INIS)

    Johnston, R.G.; Anantatmula, R.P.; Lutton, J.M.; Rivera, C.L.

    1986-01-01

    The Basalt Waste Isolation Project is evaluating the suitability of basalt in southeastern Washington State as a possible location for a nuclear waste repository. The performance of the waste package, which includes the waste form, container, and surrounding packing material, will be affected by the stability of container alloys in the repository environment. Primary corrosion phases and altered packing material containing metals leached from the container may also influence subsequent reactions between the waste form and repository environment. Copper- and iron-based alloys were tested at 50 0 to 300 0 C in an air/steam environment and in pressure vessels in ground-water-saturated basalt-bentonite packing material. Reaction phases formed on the alloys were identified and corrosion rates were measured. Changes in adhering packing material were also evaluated. The observed reactions and their possible effects on container alloy durability in the repository are discussed

  14. Regional basalt hydrology of the Columbia Plateau in Washington

    International Nuclear Information System (INIS)

    Tanaka, H.; Barrett, G.; Wildrick, L.

    1979-10-01

    This study is part of the Basalt Waste Isolation Project, operated for the US Department of Energy by Rockwell Hanford Operations. The overall purpose of the study is to assess locations within the Columbia River Basalt Group beneath the Hanford Site in south-central Washington suitable for a geologic repository for radioactive waste. This hydrologic study was made to describe the hydrologic characteristics of the basalt units of the Columbia Plateau. This was done by comprehensive data compilation, data interpretation and analysis. Data are presented in the form of maps and tables suitable as input information about the regional hydrology for possible future analysis by computer models. The report includes: an introduction; basic data; interpretation which covers stratigraphic trend surface, water levels, transmissivity and storage of aquifers, recharge, discharge, flow, subbasins, cross sections, references and appendix of record of wells

  15. Basalt woven fiber reinforced vinylester composites: Flexural and electrical properties

    International Nuclear Information System (INIS)

    Carmisciano, Salvatore; Rosa, Igor Maria De; Sarasini, Fabrizio; Tamburrano, Alessio; Valente, Marco

    2011-01-01

    A preliminary comparative study of basalt and E-glass woven fabric reinforced composites was performed. The fabrics were characterized by the same weave pattern and the laminates tested by the same fiber volume fraction. Results of the flexural and interlaminar characterization are reported. Basalt fiber composites showed higher flexural modulus and apparent interlaminar shear strength (ILSS) in comparison with E-glass ones but also a lower flexural strength and similar electrical properties. With this fiber volume fraction, scanning electron microscopy (SEM) analysis of the fractured surfaces enabled a better understanding both of the failure modes involved and of points of concern. Nevertheless, the results of this study seem promising in view of a full exploitation of basalt fibers as reinforcement in polymer matrix composites (PMCs).

  16. Corrosion and tribological properties of basalt fiber reinforced composite materials

    Science.gov (United States)

    Ha, Jin Cheol; Kim, Yun-Hae; Lee, Myeong-Hoon; Moon, Kyung-Man; Park, Se-Ho

    2015-03-01

    This experiment has examined the corrosion and tribological properties of basalt fiber reinforced composite materials. There were slight changes of weight after the occurring of corrosion based on time and H2SO4 concentration, but in general, the weight increased. It is assumed that this happens due to the basalt fiber precipitate. Prior to the corrosion, friction-wear behavior showed irregular patterns compared to metallic materials, and when it was compared with the behavior after the corrosion, the coefficient of friction was 2 to 3 times greater. The coefficient of friction of all test specimen ranged from 0.1 to 0.2. Such a result has proven that the basalt fiber, similar to the resin rubber, shows regular patterns regardless of time and H2SO4 concentration because of the space made between resins and reinforced materials.

  17. The Roles of the Yellowstone Hotspot and Crustal Assimilation in Generating Pleistocene-Holocene Basalts on the Eastern Snake River Plain

    Science.gov (United States)

    Mintz, H.; Chadwick, J.

    2017-12-01

    The southwest motion of the North American plate across the Yellowstone hotspot created a chain of age-progressive rhyolitic calderas over the past 16 myr. in southern Idaho, U.S. The focus of Yellowstone activity now resides in northwest Wyoming, but basaltic volcanism has continued in its wake in southern Idaho on the eastern Snake River Plain (ESRP). These younger basaltic lavas are not age progressive and have buried the Yellowstone rhyolites on the ESRP. The ultimate source of the basalts is commonly ascribed to the passage or presence of the hotspot. However, the mechanisms involved, and the relative roles of the hotspot, other mantle sources, and the North American crust in generating the ESRP basalts remain unclear and have been the subject of recent geochemical and isotopic studies. In this study, the role of crustal assimilation is addressed by analyzing the chemical and isotopic characteristics of some of the youngest Pleistocene-Holocene tholeiitic volcanic fields on the ESRP, which were erupted through varying thicknesses of continental crust. Samples were analyzed from the Hell's Half Acre flow (5,200 years old; all dates Kuntz et al., 1986, 1994), Cerro Grande flow (13,380 years), and Black Butte Crater (a.k.a. Shoshone) flow (10,130 years), which were erupted at distances from between about 200 to 300 km from the current location of the hotspot. The crust of the ESRP thins from northeast to southwest, from about 47 km at the Hells Half Acre flow to 40 km at the Black Butte Crater flow, a thickness difference of about 15%. The apparently similar tectonic and magmatic environments of the three sampled flows suggest the crustal thickness variation may be a primary influence on the magnitude of assimilation and therefore the isotopic characteristics of the lavas. The goal of this work is to constrain the relative role of assimilation and to understand the source(s) of the magmas and the Yellowstone hotspot contribution. Major elements, trace elements

  18. Geomorphology of crater and basin deposits - Emplacement of the Fra Mauro formation

    Science.gov (United States)

    Morrison, R. H.; Oberbeck, V. R.

    1975-01-01

    Characteristics of continuous deposits near lunar craters larger than about 1 km wide are considered, and it is concluded that (1) concentric dunes, radial ridges, and braided lineations result from deposition of the collision products of ejecta from adjacent pairs of similarly oriented secondary-crater chains and are, therefore, concentrations of secondary-crater ejecta; (2) intracrater ridges are produced within preexisting craters surrounding a fresh primary crater by ricocheting and focusing of secondary-crater ejecta from the preexisting craters' walls; and (3) secondary cratering has produced many of the structures of the continuous deposits of relatively small lunar craters and is the dominant process for emplacement of most of the radial facies of the continuous deposits of large lunar craters and basins. The percentages of Imbrium ejecta in deposits and the nature of Imbrium sculpturing are investigated.

  19. On causal links between flood basalts and continental breakup

    Science.gov (United States)

    Courtillot, V.; Jaupart, C.; Manighetti, I.; Tapponnier, P.; Besse, J.

    1999-03-01

    Temporal coincidence between continental flood basalts and breakup has been noted for almost three decades. Eight major continental flood basalts have been produced over the last 300 Ma. The most recent, the Ethiopian traps, erupted in about 1 Myr at 30 Ma. Rifting in the Red Sea and Gulf of Aden, and possibly East African rift started at about the same time. A second trap-like episode occurred around 2 Ma and formation of true oceanic crust is due in the next few Myr. We find similar relationships for the 60 Ma Greenland traps and opening of the North Atlantic, 65 Ma Deccan traps and opening of the NW Indian Ocean, 132 Ma Parana traps and South Atlantic, 184 Ma Karoo traps and SW Indian Ocean, and 200 Ma Central Atlantic Margin flood basalts and opening of the Central Atlantic Ocean. The 250 Ma Siberian and 258 Ma Emeishan traps seem to correlate with major, if aborted, phases of rifting. Rifting asymmetry, apparent triple junctions and rift propagation (towards the flood basalt area) are common features that may, together with the relative timings of flood basalt, seaward dipping reflector and oceanic crust production, depend on a number of plume- and lithosphere- related factors. We propose a mixed scenario of `active/passive' rifting to account for these observations. In all cases, an active component (a plume and resulting flood basalt) is a pre-requisite for the breakup of a major oceanic basin. But rifting must be allowed by plate-boundary forces and is influenced by pre-existing heterogeneities in lithospheric structure. The best example is the Atlantic Ocean, whose large-scale geometry with three large basins was imposed by the impact points of three mantle plumes.

  20. Technetium and neptunium reactions in basalt/groundwater systems

    International Nuclear Information System (INIS)

    Meyer, R.E.; Arnold, W.D.; Kelmers, A.D.; Kessler, J.H.; Clark, R.J.; Johnson, J.S. Jr.; Young, G.C.; Case, F.I.; Westmoreland, C.G.

    1985-01-01

    Sorption isotherms and apparent concentration limits for Tc(VII) and Np(V) for a variety of groundwater/basalt systems were determined using Grande Ronde basalt samples representative of the Hanford Site candidate high-level waste repository. Under oxic redox conditions (air present), little or no sorption of technetium was observed; neptunium exhibited low to moderate sorption ratios. Under anoxic redox conditions (oxygen-free), low to moderate sorption of technetium was often observed, but the extent of sorption was highly dependent upon the groundwater composition and the method of pretreatment (if any) of the basalt. Sorption isotherms for technetium under reducing redox conditions (hydrazine added) indicate an apparent concentration limit of approximately 10 -6 mol/l Tc. No apparent concentration limit was found for neptunium for concentrations in groundwater up to 10 -6 mol/l and 8 x 10 -7 mol/l under oxic and reducing (hydrazine added) redox conditions, respectively. Valence control and valence analysis experiments suggest that the sorption or precipitation of Tc and Np from groundwater in the presence of basalt may result from a heterogeneous reaction occurring on the surface of the basalt. One of the critical factors of this reduction reaction appears to be the accessibility of the reactive ferrous iron component of the basalt. The laboratory simulation of groundwater redox conditions representative of the repository environment through the use of solution phase redox reagents is of questionable validity, and information obtained by such experimental methods may not be defensible for site performance assessment calculations. Anoxic experiments conducted in an argon-filled glove box appear better suited for the laboratory simulation of in situ redox conditions. 15 references, 6 figures

  1. Technetium and neptunium reactions in basalt/groundwater systems

    International Nuclear Information System (INIS)

    Meyer, R.E.; Arnold, W.D.; Kelmers, A.D.; Kessler, J.H.; Clark, R.J.; Johnson, J.S. Jr.; Young, G.C.; Case, F.I.; Westmoreland, C.G.; Florida State Univ., Tallahassee)

    1984-01-01

    Sorption isotherms and apparent concentration limits for Tc(VII) and Np(V) for a variety of groundwater/basalt systems were determined using Grande Ronde basalt samples representative of the Hanford Site candidate high-level waste repository. Under oxic redox conditions (air present), little or no sorption of technetium was observed; neptunium exhibited low to moderate sorption ratios. Under anoxic redox conditions (oxygen-free), low to moderate sorption of technetium was often observed, but the extent of sorption was highly dependent upon the groundwater composition and the method of pretreatment (if any) of the basalt. Sorption isotherms for technetium under reducing redox conditions (hydrazine added) indicate an apparent concentration limit of approximately 10 -6 mol/L Tc. No apparent concentration limit was found for neptunium for concentrations in groundwater up to approx. 10 -6 mol/L and 8 x 10 -7 mol/L under oxic and reducing (hydrazine added) redox conditions, respectively. Valence control and valence analysis experiments suggest that the sorption or precipitation of Tc and Np from groundwater in the presence of basalt may result from a heterogeneous reaction occurring on the surface of the basalt. One of the critical factors of this reduction reaction appears to be the accessibility of the reactive ferrous iron component of the basalt. The laboratory simulation of groundwater redox conditions representative of the repository environment through the use of solution phase redox reagents is of questionable validity, and information obtained by such experimental methods may not be defensible for site performance assessment calculations. Anoxic experiments conducted in an argon-filled glove box appear better suited for the laboratory simulation of in situ redox conditions. 15 refs., 6 tabs

  2. Basalt fiber reinforced polymer composites: Processing and properties

    Science.gov (United States)

    Liu, Qiang

    A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

  3. Hydrothermal waste package interactions with methane-containing basalt groundwater

    International Nuclear Information System (INIS)

    McGrail, B.P.

    1984-01-01

    Hydrothermal waste package interaction tests were conducted with a mixture of crushed glass, basalt, and steel in methane-containing synthetic basalt groundwater. In the absence of gamma radiolysis, methane was found to have little influence on the corrosion behavior of the waste package constituents. Under gamma radiolysis, methane was found to significantly lower the solution oxidation potential when compared to identical tests without methane. In addition, colloidal hydrocarbon polymers that have been produced under the irradiation conditions of these experiments were not formed. The presence of the waste package constituents apparently inhibited the formation of the polymers. However, the mechanism which prevented their formation was not determined

  4. Feasibility of storing radioactive wastes in Columbia River basalts

    International Nuclear Information System (INIS)

    Deju, R.A.

    1976-01-01

    In 1968 Atlantic Richfield Hanford Company initiated a study to assess the feasibility of final geologic storage of Hanford defense, radioactive waste in deep caverns constructed in the Columbia River flood basalts. The project, which included geologic studies, hydrologic tests, heat flow analysis, compatibility analysis, and tectonic studies, was suspended in 1972 before completion of interpretive work. In 1976 the interpretation and documentation were completed. These data may be valuable in qualifying the Columbia River flood basalts as a viable medium for final geologic storage of commercial radioactive waste. The findings to date are summarized, and the proposed future work is presented

  5. Friction Joint Between Basalt-Reinforced Composite and Aluminum

    DEFF Research Database (Denmark)

    Costache, Andrei; Glejbøl, Kristian; Sivebæk, Ion Marius

    2015-01-01

    The purpose of this study was to anchor basalt-reinforced polymers in an aluminum grip using dry friction. Dry friction clamping is considered the optimal solution for post-mounting of load-bearing terminations on composite structures. A new test method is presented for characterizing the frictio......The purpose of this study was to anchor basalt-reinforced polymers in an aluminum grip using dry friction. Dry friction clamping is considered the optimal solution for post-mounting of load-bearing terminations on composite structures. A new test method is presented for characterizing...

  6. Crater topography on Titan: Implications for landscape evolution

    Science.gov (United States)

    Neish, C.; Kirk, R.; Lorenz, R.; Bray, V.; Schenk, P.; Stiles, B.; Turtle, E.; Cassini Radar Team

    2012-04-01

    Unique among the icy satellites, Titan’s surface shows evidence for extensive modification by fluvial and aeolian erosion, which act to change the topography of its surface over time. Quantifying the extent of this landscape evolution is difficult, since the original, ‘non-eroded’ surface topography is generally unknown. However, fresh craters on icy satellites have a well-known shape and morphology, which has been determined from extensive studies on the airless worlds of the outer solar system (Schenk et al., 2004). By comparing the topography of craters on Titan to similarly sized, pristine analogues on airless bodies, we can obtain one of the few direct measures of the amount of erosion that has occurred on Titan. Cassini RADAR has imaged >30% of the surface of Titan, and more than 60 potential craters have been identified in this data set (Wood et al., 2010; Neish and Lorenz, 2012). Topographic information for these craters can be obtained from a technique known as ‘SARTopo’, which estimates surface heights by comparing the calibration of overlapping synthetic aperture radar (SAR) beams (Stiles et al., 2009). We present topography data for several craters on Titan, and compare the data to similarly sized craters on Ganymede, for which topography has been extracted from stereo-derived digital elevation models (Bray et al., 2012). We find that the depths of craters on Titan are generally within the range of depths observed on Ganymede, but several hundreds of meters shallower than the average (Fig. 1). A statistical comparison between the two data sets suggests that it is extremely unlikely that Titan’s craters were selected from the depth distribution of fresh craters on Ganymede, and that is it much more probable that the relative depths of Titan are uniformly distributed between ‘fresh’ and ‘completely infilled’. This is consistent with an infilling process that varies linearly with time, such as aeolian infilling. Figure 1: Depth of

  7. Vegetation damage and recovery after Chiginagak Volcano Crater drainage event

    Data.gov (United States)

    Department of the Interior — From August 20 — 23, 2006, I revisited Chiginigak volcano to document vegetation recovery after the crater drainage event that severely damaged vegetation in May of...

  8. LRO MOON CRATER EDR RAWDATA VERSION 1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set comprises the raw binary data from from the LRO Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument. The data consists of the...

  9. Mars Climate History: Insights From Impact Crater Wall Slope Statistics

    Science.gov (United States)

    Kreslavsky, Mikhail A.; Head, James W.

    2018-02-01

    We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.

  10. Extreme Access & Lunar Ice Mining in Permanently Shadowed Craters

    Data.gov (United States)

    National Aeronautics and Space Administration — Results from the recent NASA Lunar CRater Observation and Sensing Satellite, or LCROSS, mission in 2010, indicate that water (H2O), ice and other useful volatiles...

  11. Site characterization requirements for nuclear-cratering design

    International Nuclear Information System (INIS)

    Terhune, R.W.; Carlson, R.C.

    1977-01-01

    A material properties measurement program for the design of large engineering nuclear-excavation projects by computer calculation is presented. Material properties of the site and their relative effect on crater size are analyzed and ordered in relation to their importance in determining the overall cratering efficiency. The measurement program includes both in situ logging and laboratory measurement of core samples, together with the reason for each measurement and its use in the calculations

  12. A global catalogue of Ceres impact craters ≥ 1 km and preliminary analysis

    Science.gov (United States)

    Gou, Sheng; Yue, Zongyu; Di, Kaichang; Liu, Zhaoqin

    2018-03-01

    The orbital data products of Ceres, including global LAMO image mosaic and global HAMO DTM with a resolution of 35 m/pixel and 135 m/pixel respectively, are utilized in this research to create a global catalogue of impact craters with diameter ≥ 1 km, and their morphometric parameters are calculated. Statistics shows: (1) There are 29,219 craters in the catalogue, and the craters have a various morphologies, e.g., polygonal crater, floor fractured crater, complex crater with central peak, etc.; (2) The identifiable smallest crater size is extended to 1 km and the crater numbers have been updated when compared with the crater catalogue (D ≥ 20 km) released by the Dawn Science Team; (3) The d/D ratios for fresh simple craters, obviously degraded simple crater and polygonal simple crater are 0.11 ± 0.04, 0.05 ± 0.04 and 0.14 ± 0.02 respectively. (4) The d/D ratios for non-polygonal complex crater and polygonal complex crater are 0.08 ± 0.04 and 0.09 ± 0.03. The global crater catalogue created in this work can be further applied to many other scientific researches, such as comparing d/D with other bodies, inferring subsurface properties, determining surface age, and estimating average erosion rate.

  13. Preliminary feasibility study on storage of radioactive wastes in Columbia River basalts. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    ,

    1976-11-01

    Volume II comprises four appendices: analytical data and sample locations for basalt flow type localities; Analytical data and sample locations for measured field sections in Yakima basalts; core hole lithology and analytical data; and geophysical logs. (LK)

  14. Mobilization of manganese by basalt associated Mn(II)-oxidizing bacteria from the Indian Ridge System

    Digital Repository Service at National Institute of Oceanography (India)

    Sujith, P.P.; Mourya, B.S.; Krishnamurthi, S.; Meena, R.M.; LokaBharathi, P.A.

    The Indian Ridge System basalt bearing Mn-oxide coatings had todorokite as the major and birnesite as the minor mineral. We posit that microorganisms associated with these basalts participate in the oxidation of Mn and contribute to mineral...

  15. Petrographical indicators of petrogenesis: Examples from Central Indian Ocean Basin basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Mislankar, P.G.; Iyer, S.D.

    Petrographical features of the Central Indian Basin (CIOB) basalts were studied to understand their genetic significance. The fresh basaltic pillows show three textural zones from the top glassy (zone A) through the intermediate (zone B...

  16. Use of solar power for the production of basalt-based mineral fibers

    International Nuclear Information System (INIS)

    Gulamova, D. D.; Shevchenko, V. P.; Tokunov, S. G.; Kim, R. B.

    2012-01-01

    The possibility of obtaining basalt mineral fibers using concentrating solar power and melt-quench technique is shown. The microstructure and physicochemical properties of basalt fibers are analyzed. (author)

  17. Morphological indicators of a mascon beneath Ceres' largest crater, Kerwan

    Science.gov (United States)

    Bland, Michael T.; Ermakov, Anton; Raymond, Carol A.; Williams, David A.; Bowling, Tim J.; Preusker, F.; Park, Ryan S.; Marchi, Simone; Castillo-Rogez, Julie C.; Fu, R.R.; Russell, Christopher T.

    2018-01-01

    Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long‐term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact‐induced uplift of the high‐density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest‐degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin‐associated gravity anomalies, although their origin may differ substantially.

  18. Formation of perched lava ponds on basaltic volcanoes: Interaction between cooling rate and flow geometry allows estimation of lava effusion rates

    Science.gov (United States)

    Wilson, L.; Parfitt, E. A.

    1993-01-01

    Perched lava ponds are infrequent but distinctive topographic features formed during some basaltic eruptions. Two such ponds, each approximately 150 m in diameter, formed during the 1968 eruption at Napau Crater and the 1974 eruption of Mauna Ulu, both on Kilauea Volcano, Hawaii. Each one formed where a channelized, high volume flux lava flow encountered a sharp reduction of slope: the flow spread out radially and stalled, forming a well-defined terminal levee enclosing a nearly circular lava pond. We describe a model of how cooling limits the motion of lava spreading radially into a pond and compare this with the case of a channelized flow. The difference in geometry has a major effect, such that the size of a pond is a good indicator of the volume flux of the lava forming it. Lateral spreading on distal shallow slopes is a major factor limiting the lengths of lava flows.

  19. Bonding Properties of Basalt Fiber and Strength Reduction According to Fiber Orientation

    OpenAIRE

    Choi, Jeong-Il; Lee, Bang

    2015-01-01

    The basalt fiber is a promising reinforcing fiber because it has a relatively higher tensile strength and a density similar to that of a concrete matrix as well as no corrosion possibility. This study investigated experimentally the bonding properties of basalt fiber with cementitious material as well as the effect of fiber orientation on the tensile strength of basalt fiber for evaluating basalt fiber?s suitability as a reinforcing fiber. Single fiber pullout tests were performed and then th...

  20. Dust coatings on basaltic rocks and implications for thermal infrared spectroscopy of Mars

    Science.gov (United States)

    Johnson, J. R.; Christensen, P.R.; Lucey, P.G.

    2002-01-01

    Thin coatings of atmospherically deposited dust can mask the spectral characteristics of underlying surfaces on Mars from the visible to thermal infrared wavelengths, making identification of substrate and coating mineralogy difficult from lander and orbiter spectrometer data. To study the spectral effects of dust coatings, we acquired thermal emission and hemispherical reflectance spectra (5-25 μm; 2000-400 cm-1) of basaltic andesite coated with different thicknesses of air fall-deposited palagonitic soils, fine-grained ceramic clay powders, and terrestrial loess. The results show that thin coatings (10-20 μm) reduce the spectral contrast of the rock substrate substantially, consistent with previous work. This contrast reduction continues linearly with increasing coating thickness until a "saturation thickness" is reached, after which little further change is observed. The saturation thickness of the spectrally flat palagonite coatings is ~100-120 μm, whereas that for coatings with higher spectral contrast is only ~50-75 μm. Spectral differences among coated and uncoated samples correlate with measured coating thicknesses in a quadratic manner, whereas correlations with estimated surface area coverage are better fit by linear functions. Linear mixture modeling of coated samples using the rock substrate and coating materials as end-members is also consistent with their measured coating thicknesses and areal coverage. A comparison of ratios of Thermal Emission Spectrometer (TES) spectra of dark and bright intracrater and windstreak deposits associated with Radau crater suggests that the dark windstreak material may be coated with as much as 90% areal coverage of palagonitic dust. The data presented here also will help improve interpretations of upcoming mini-TES and Thermal Emission Imaging System (THEMIS) observations of coated Mars surface materials.

  1. 100 New Impact Crater Sites Found on Mars

    Science.gov (United States)

    Kennedy, M. R.; Malin, M. C.

    2009-12-01

    Recent observations constrain the formation of 100 new impact sites on Mars over the past decade; 19 of these were found using the Mars Global Surveyor Mars Orbiter Camera (MOC), and the other 81 have been identified since 2006 using the Mars Reconnaissance Orbiter Context Camera (CTX). Every 6 meter/pixel CTX image is examined upon receipt and, where they overlap images of 0.3-240 m/pixel scale acquired by the same or other Mars-orbiting spacecraft, we look for features that may have changed. New impact sites are initially identified by the presence of a new dark spot or cluster of dark spots in a CTX image. Such spots may be new impact craters, or result from the effect of impact blasts on the dusty surface. In some (generally rare) cases, the crater is sufficiently large to be resolved in the CTX image. In most cases, however, the crater(s) cannot be seen. These are tentatively designated as “candidate” new impact sites, and the CTX team then creates an opportunity for the MRO spacecraft to point its cameras off-nadir and requests that the High Resolution Imaging Science Experiment (HiRISE) team obtain an image of ~0.3 m/pixel to confirm whether a crater or crater cluster is present. It is clear even from cursory examination that the CTX observations are areographically biased to dusty, higher albedo areas on Mars. All but 3 of the 100 new impact sites occur on surfaces with Lambert albedo values in excess of 23.5%. Our initial study of MOC images greatly benefited from the initial global observations made in one month in 1999, creating a baseline date from which we could start counting new craters. The global coverage by MRO Mars Color Imager is more than a factor of 4 poorer in resolution than the MOC Wide Angle camera and does not offer the opportunity for global analysis. Instead, we must rely on partial global coverage and global coverage that has taken years to accumulate; thus we can only treat impact rates statistically. We subdivide the total data

  2. Flame-resistant pure and hybrid woven fabrics from basalt

    Science.gov (United States)

    Jamshaid, H.; Mishra, R.; Militky, J.

    2017-10-01

    This work has been formulated to investigate the burning behavior of different type of fabrics. The main concentration is to see how long the fabric resists after it catches the fire and the propagation of fire can be reduced by using flame resistant fiber i.e basalt. Basalt fiber is an environmental friendly material with low input, high output, low energy consumption and less emission. The goal of present investigations is to show the dependence of fabric flammability on its structure parameters i.e weave type, blend type etc. Fabric weaves have strong effect on flammability properties. Plain weave has the lowest burning rate as the density of the plain weave fabric is more and the structure is tight which gives less chances of flame passing through the fabric. Thermal stability is evaluated with TGA of all hybrid and nonhybrid fabrics and compared. The thermal stability of the basalt fiber is excellent. When comparing thermal analysis curves for hybrid samples it demonstrates that thermal stability of the samples containing basalt is much higher than the non- hybrid samples. Percentage weight loss is less in hybrid samples as compared to non-hybrid samples. The effectiveness of hybridization on samples may be indicated by substantial lowering of the decomposition mass. Correlation was made between flammability with the infrared radiations (IR)

  3. Age of the youngest Palaeogene flood basalts in East Greenland

    DEFF Research Database (Denmark)

    Heilmann-Clausen, C.; Piasecki, Stefan; Abrahamsen, Niels

    2008-01-01

    results, this constrains the termination of the East Greenland Paleogene Igneous Province to the Early-Middle Eocene transition (nannoplankton chronozones NP13-NP14/earliest NP15). This is 6-8 Ma younger than according to previous biostratigraphic age assignments. The new data show that flood basalt...

  4. Nuclear waste package materials testing report: basaltic and tuffaceous environments

    International Nuclear Information System (INIS)

    Bradley, D.J.; Coles, D.G.; Hodges, F.N.; McVay, G.L.; Westerman, R.E.

    1983-03-01

    The disposal of high-level nuclear wastes in underground repositories in the continental United States requires the development of a waste package that will contain radionuclides for a time period commensurate with performance criteria, which may be up to 1000 years. This report addresses materials testing in support of a waste package for a basalt (Hanford, Washington) or a tuff (Nevada Test Site) repository. The materials investigated in this testing effort were: sodium and calcium bentonites and mixtures with sand or basalt as a backfill; iron and titanium-based alloys as structural barriers; and borosilicate waste glass PNL 76-68 as a waste form. The testing also incorporated site-specific rock media and ground waters: Reference Umtanum Entablature-1 basalt and reference basalt ground water, Bullfrog tuff and NTS J-13 well water. The results of the testing are discussed in four major categories: Backfill Materials: emphasizing water migration, radionuclide migration, physical property and long-term stability studies. Structural Barriers: emphasizing uniform corrosion, irradiation-corrosion, and environmental-mechanical testing. Waste Form Release Characteristics: emphasizing ground water, sample surface area/solution volume ratio, and gamma radiolysis effects. Component Compatibility: emphasizing solution/rock, glass/rock, glass/structural barrier, and glass/backfill interaction tests. This area also includes sensitivity testing to determine primary parameters to be studied, and the results of systems tests where more than two waste package components were combined during a single test

  5. Genetic aspects of basalts from the Carlsberg Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    of the CR rocks are sparse. The bulk chemical, mineral chemical and ore mineralization aspects of the dredged basalts from a segment of the CR (at 3°37¢N, 64°57¢E) are synthesized to indicate the influence of fractional crystallization coupled with magma...

  6. Gas adsorption on crushed quartz and basalt. [in vacuum

    Science.gov (United States)

    Barker, C.; Torkelson, B. E.

    1975-01-01

    The new surfaces generated by crushing rocks and minerals adsorb gases. Different gases are adsorbed to different extents so that both the total amount and composition of the released gases are changed. This affects the interpretation of the composition of the gases obtained by vacuum crushing lunar basalts, meteorites and minerals with fluid inclusions.

  7. Petrology of spinel lherzolite xenoliths in alkali basalts from Liri ...

    African Journals Online (AJOL)

    Al2O3), and Al-rich spinel occur in alkali basalts from Liri, South of the ... these spinel lherzolite xenoliths are reported, along with the analyses of ...... erupted in the Liri region. .... and temperatures with controlled activities of water, carbon.

  8. Petrography and chemistry of basalts from the Carlsberg ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Iyer, S.D.

    interior through a variolitic zone. The silica-alkalies relation show these basalts to be of sub-alkaline nature. Variable normative compositions and Mg number, increase in alkali index, differences in Al2O3/CaO and FeO/MgO ratios, variable trace element...

  9. Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

    Directory of Open Access Journals (Sweden)

    al-Swaidani Aref M.

    2015-11-01

    Full Text Available The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction. Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289 and accelerated mortar bar test (ASTM C1260 have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida’a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

  10. Basalt Waste Isolation Project. Annual report, fiscal year 1979

    International Nuclear Information System (INIS)

    1979-11-01

    This project is aimed at examining the feasibility and providing the technology to design and construct a radwaste repository in basalt formations beneath and within the Hanford Site. The project is divided into seven areas: systems integration, geosciences, hydrologic studies, engineered barriers, near-surface test facility, engineering testing, and repository engineering. This annual report summarizes key investigations in these seven areas

  11. Evaluation of basalt flows as a waste isolation media

    International Nuclear Information System (INIS)

    Deju, R.A.

    1978-01-01

    Activities in basalt waste isolation programs in the Columbia River basin are reported. Work during the period is summarized for the overall program which is divided into systems integration, geology, hydrology, engineered barriers studies, engineering testing, and the construction of a near-surface test facility

  12. Nature and composition of interbedded marine basaltic pumice in the

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 2. Nature and composition of interbedded marine basaltic pumice in the ~52–50 Ma Vastan lignite sequence, western India: Implication for Early Eocene MORB volcanism offshore Arabian Sea. Sarajit Sensarma Hukam Singh R S Rana Debajyoti Paul ...

  13. Fire performance of basalt FRP mesh reinforced HPC thin plates

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2013-01-01

    An experimental program was carried out to investigate the influence of basalt FRP (BFRP) reinforcing mesh on the fire behaviour of thin high performance concrete (HPC) plates applied to sandwich elements. Samples with BFRP mesh were compared to samples with no mesh, samples with steel mesh...

  14. Hydrologic testing methodology and results from deep basalt boreholes

    International Nuclear Information System (INIS)

    Strait, S.R.; Spane, F.A.; Jackson, R.L.; Pidcoe, W.W.

    1982-05-01

    The objective of the hydrologic field-testing program is to provide data for characterization of the groundwater systems wihin the Pasco Basin that are significant to understanding waste isolation. The effort is directed toward characterizing the areal and vertical distributions of hydraulic head, hydraulic properties, and hydrochemistry. Data obtained from these studies provide input for numerical modeling of groundwater flow and solute transport. These models are then used for evaluating potential waste migration as a function of space and time. The groundwater system beneath the Hanford Site and surrounding area consists of a thick, accordantly layered sequence of basalt flows and associated sedimentary interbed that primarily occur in the upper part of the Columbia River basalt. Permeable horizons of the sequence are associated with the interbeds and the interflow zones within the basalt. The columnar interiors of a flow act as low-permeability aquitards, separating the more-permeable interflows or interbeds. This paper discusses the hydrologic field-gathering activities, specifically, field-testing methodology and test results from deep basalt boreholes

  15. Heat resistance study of basalt fiber material via mechanical tests

    Science.gov (United States)

    Gao, Y. Q.; Jia, C.; Meng, L.; Li, X. H.

    2017-12-01

    This paper focuses on the study of the relationship between the fracture strength of basalt rovings and temperature. Strong stretching performance of the rovings has been tested after the treatment at fixed temperatures but different heating time and then the fracture strength of the rovings exposed to the heating at different temperatures and cooled in different modes investigated. Finally, the fracture strength of the basalt material after the heat treatment was studied. The results showed that the room-temperature strength tends to decrease with an increase of the heat treatment time at 250 °C, but it has the local maximum after 2h heating. And the basalt rovings strength increased after the heat treatment up to 200 °C. It was 16.7 percent higher than the original strength. The strength depends not only on the temperature and duration of the heating, but also on the cooling mode. The value of the strength measured after cold water cooling was less by 6.3% compared with an ambient air cooling mode. The room-temperature breaking strength of the rovings heated at 200 °C and 100 °C for 2 hours each increased by about 14.6% with respect to unpretreated basalt rovings.

  16. Geological Mapping of Impact Melt Deposits at Lunar Complex Craters: New Insights into Morphological Diversity, Distribution and the Cratering Process

    Science.gov (United States)

    Dhingra, D.; Head, J. W., III; Pieters, C. M.

    2014-12-01

    We have completed high resolution geological mapping of impact melt deposits at the young lunar complex craters (wall and rim impact melt units and their relation to floor units have also been mapped. Among the distinctive features of these impact melt deposits are: 1) Impact Melt Wave Fronts: These are extensive (sometimes several kilometers in length) and we have documented their occurrence and distribution in different parts of the crater floor at Jackson and Tycho. These features emphasize melt mobility and style of emplacement during the modification stage of the craters. 2) Variations in Floor Elevations: Spatially extensive and coherent sections of crater floors have different elevations at all the three craters. The observed elevation differences could be caused by subsidence due to cooling of melt and/or structural failure, together with a contribution from regional slope. 3) Melt-Covered Megablocks: We also observe large blocks/rock-fragments (megablocks) covered in impact melt, which could be sections of collapsed wall or in some cases, subdued sections of central peaks. 4) Melt-Covered Central Peaks: Impact melt has also been mapped on the central peaks but varies in spatial extent among the craters. The presence of melt on peaks must be taken into account when interpreting peak mineralogy as exposures of deeper crust. 5) Boulder Distribution: Interesting trends are observed in the distribution of boulder units of various sizes; some impact melt units have spatially extensive boulders, while boulder distribution is very scarce in other units on the floor. We interpret these distributions to be influenced by a) the differential collapse of the crater walls during the modification stage, and b) the amount of relative melt volume retained in different parts of the crater floor. These observations provide important documentation of the morphological diversity and better understanding of the emplacement and final distribution of impact melt deposits.

  17. Temperature profiles from Pos Crater Lake

    Science.gov (United States)

    Neshyba, Steve; Fernandez, Walter; Diaz-Andrade, José

    In 1984, we took part in an expedition to measure the temperature field and bathymetry of the acid lake (Figure 1) that has formed in the crater of Poás volcano, Costa Rica, since its last eruption in 1953. Obtaining these data was the first step in a long-range study planned by researchers at the Center for Geophysical Research, University of Costa Rica (San Jose, Costa Rica), and the College of Oceanography, Oregon State University (Corvallis). The study will eventually consider all aspects of fluid behavior in a volcanic lake that is heated or otherwise convectively driven by energy injected at the lake bottom.Evidence of convection is clearly visible on the surface of the Poás lake most of the time. Fumarole activity has been continuous since 1953. Phreatic explosions are quite frequent, varying from weak to strong, and the height of the ejected column varies from 1 to more than 500 m. One immediately useful result of the research would be an estimate of the heat transfer from sources within the conduit to the overlying water column. As far as geophysical fluid behavior goes, we are interested in the turbulent and diffusive processes by which heat and chemical species are transferred. We are especially interested in the impact on the density stratification of the density changes that occur as particulates settle downward through the fluid column. The stratification would otherwise be controlled by the turbulent and diffusive processes driven by thermochemical factors.

  18. Depleted basaltic lavas from the proto-Iceland plume, Central East Greenland

    DEFF Research Database (Denmark)

    Waight, Tod Earle; Baker, Joel A.

    2012-01-01

    New geochemical and isotopic data are presented for volumetrically minor, depleted low-Ti basalts that occur in the Plateau Basalt succession of central East Greenland (CEG), formed during the initial stages of opening of the North Atlantic at 55 Ma. The basalts have MORB-like geochemistry (e.g. ...

  19. Geochemical study of young basalts in East Azerbaijan (Northwest of Iran

    Directory of Open Access Journals (Sweden)

    Nasir Amel

    2016-12-01

    Full Text Available The young basalts in East Azerbaijan are placed in West Alborz – Azerbaijan zone. Volcanic activities have extended from the Pliocene to the Quaternary by eruption from fracture systems and faults. Rocks under study are olivine-basalt and trachybasalts. The main minerals are olivine, pyroxene, plagioclase set in glassy or microcrystalline matrix and olivine are present as phenocryst. The textures in the studied rocks are mainly hyaloporphyric, hyalomicrolitic and porphyritic. Trace elements and rare earth elements on spider diagrams have high LREE/HREE ratio. Rare earth elements on diagram display negative slope indicating alkaline nature for the basalts under study. As it may be observed, on tectonic diagrams, the Marand basalts are placed on Island Arc basalt (IAB field, whereas the Ahar, Heris, Kalaibar and Miyaneh basalts are classified as Ocean Island Basalts (OIB and finally the basalts of Sohrol area are plotted on continental rift Basalt (CRB field. The Marand and Sohrol basalts were likely originated from lithospheric - astenospheric mantle with 2 to 5 % partial melting whereas, the Ahar, Heris and Kalaibar basalts having same source experienced 1-2% partial melting rate and the Miyaneh basalts possibly produced from lithospheric mantle with 10-20% partial melting rate pointing to shallow depth of mantle and the higher rate of melting. Based on tectonic setting diagrams, all the rocks studied are plotted in post collisional environments.

  20. Behaviour of rare earth elements, as natural analogues of transuranium elements, during weathering of basaltic glasses

    International Nuclear Information System (INIS)

    Daux, V.; Crovisier, J.L.; Petit, J.C.

    1991-01-01

    Subglacial basaltic glasses from Iceland have been studied in order to investigate REE behaviour low-temperature weathering. Just as actinides accumulate in the hydrated superficial corrosion layer of borosilicate glasses, REEs are found to be enriched in the natural corrosion layer of basaltic glasses (palagonite). However, this enrichment is only relative for basaltic glasses [fr

  1. Alberca De Guadalupe Maar Crater, Zacapu Basin : A Rare Type of Volcano within the Michoacán-Guanajuato Volcanic Field, México

    Science.gov (United States)

    Kshirsagar, P. V.; Siebe, C.; Guilbaud, M. N.; Salinas, S.

    2014-12-01

    Phreato-magmatic vents (esp. maar craters) are rare in the ~40,000 Km2 Plio-Quaternary monogenetic Michoacán-Guanajuato Volcanic Field (MGVF) located in the central part of the Mexican Volcanic Belt. In contrast to >1000 scoria cones, only 2 dozen phreato-magmatic monogenetic vents (e.g. tuff cones, tuff rings, and maars) have been identified. About half of these form a cluster near Valle de Santiago in the Lerma river valley at the northern margin of the MGVF, while the others occur in a rather scattered fashion. Here we discuss the origin of Alberca de Guadalupe maar crater, one of the three phreato-magmatic vents (in addition to El Caracol and Alberca de Los Espinos) that occur within the boundaries of the inter-montane lacustrine Zacapu basin, a tectonic graben bound by an ENE-WSW normal fault system. The maar crater came into existence between 20,000 and 23,000 y BP, forming a 140 m deep hole in the otherwise planar surrounding ground of theearly Pleistocene lava flows of Cerro Pelón.The maar crater has a diameter of ~1 Km and bears a 9 m deep lake. Eruptive products include typical surge deposits that are best exposed around the rim and inner crater walls. They are poorly sorted (Mdø= -1.56 to -3.75, ø= 1.43 to 3.23), rich in accidental lithics (angular andesitic lava and ignimbrite clasts) constituting 51-88% of the deposit with few juveniles (basaltic andesite with phenocrysts of plagioclase, olivine, and pyroxene in a quenched glassy matrix; SiO2=54-58 wt. %). Dry surge units are friable and clast-supported, in contrast the wet surge units are fairly indurated and bear accretionary lapilli. Bedding is frequently distorted by ballistic impact-sag structures. The entire construct is disrupted by an E-W trending regional fault, downthrowing the northern part by ~30 m.The unusual formation of this maar crater in the semi-arid highlands of Zacapu was favored by the local hydrological and topographical conditions. Such conditions still prevail in several

  2. Dynamics of crater formations in immersed granular materials

    Science.gov (United States)

    Varas, G.; Vidal, V.; Géminard, J.

    2009-12-01

    Craters are part of the widespread phenomena observed in nature. Among the main applications to natural phenomena, aside from meteorite impact craters, are the formation and growth of volcanic edifices, by successive ejecta emplacement and/or erosion. The time evolution and dynamics play a crucial role here, as the competition between volcanic-jet mass-flux (degassing and ejecta) and crater-size evolution may control directly the eruptive regime. Crater morphology in dry granular material has been extensively studied, both experimentally and theoretically. Most of these studies investigate the final, steady crater shape resulting from the collision of solid bodies with the material surface and scaling laws are derived. In immersed granular material, craters generated by an underwater vortex ring, or underwater impact craters generated by landslide, have been reported. In a previous experimental study, Gostiaux et al. [Gran. Matt., 2002] have investigated the dynamics of air flowing through an immersed granular layer. They reported that, depending on the flow rate, the system exhibits two qualitatively different regimes: At small flow rate, the bubbling regime during which bubbles escape the granular layer independently one from another; At large flow rate, the open-channel regime which corresponds to the formation of a channel crossing the whole thickness of the granular bed through which air escapes almost continuously. At intermediate flow rate, a spontaneous alternation between these two regimes is observed. Here, we report the dynamics of crater formations at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. We reproduce the experimental conditions of Gostiaux et al. (2002) in two dimensions: In a vertical Hele-Shaw cell, the crater consists of two sand piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas

  3. Planetary boundary layer and circulation dynamics at Gale Crater, Mars

    Science.gov (United States)

    Fonseca, Ricardo M.; Zorzano-Mier, María-Paz; Martín-Torres, Javier

    2018-03-01

    The Mars implementation of the Planet Weather Research and Forecasting (PlanetWRF) model, MarsWRF, is used here to simulate the atmospheric conditions at Gale Crater for different seasons during a period coincident with the Curiosity rover operations. The model is first evaluated with the existing single-point observations from the Rover Environmental Monitoring Station (REMS), and is then used to provide a larger scale interpretation of these unique measurements as well as to give complementary information where there are gaps in the measurements. The variability of the planetary boundary layer depth may be a driver of the changes in the local dust and trace gas content within the crater. Our results show that the average time when the PBL height is deeper than the crater rim increases and decreases with the same rate and pattern as Curiosity's observations of the line-of-sight of dust within the crater and that the season when maximal (minimal) mixing is produced is Ls 225°-315° (Ls 90°-110°). Thus the diurnal and seasonal variability of the PBL depth seems to be the driver of the changes in the local dust content within the crater. A comparison with the available methane measurements suggests that changes in the PBL depth may also be one of the factors that accounts for the observed variability, with the model results pointing towards a local source to the north of the MSL site. The interaction between regional and local flows at Gale Crater is also investigated assuming that the meridional wind, the dynamically important component of the horizontal wind at Gale, anomalies with respect to the daily mean can be approximated by a sinusoidal function as they typically oscillate between positive (south to north) and negative (north to south) values that correspond to upslope/downslope or downslope/upslope regimes along the crater rim and Mount Sharp slopes and the dichotomy boundary. The smallest magnitudes are found in the northern crater floor in a region that

  4. A Numerical Investigation into Low-Speed Impact Cratering Events

    Science.gov (United States)

    Schwartz, Stephen; Richardson, D. C.; Michel, P.

    2012-10-01

    Impact craters are the geological features most commonly observed on the surface of solid Solar System bodies. Crater shapes and features are crucial sources of information regarding past and present surface environments, and can provide indirect information about the internal structures of these bodies. In this study, we consider the effects of low-speed impacts into granular material. Studies of low-speed impact events are suitable for understanding the cratering process leading, for instance, to secondary craters. In addition, upcoming asteroid sample return missions will employ surface sampling strategies that use impacts into the surface by a projectile. An understanding of the process can lead to better sampling strategies. We use our implementation of the Soft-Sphere Discrete Element Method (SSDEM) (Schwartz et al. 2012, Granular Matter 14, 363-380) into the parallel N-body code PKDGRAV (cf. Richardson et al. 2011, Icarus 212, 427-437) to model the impact cratering process into granular material. We consider the effects of boundary conditions on the ejecta velocity profile and discuss how results relate to the Maxwell Z-Model during the crater growth phase. Cratering simulations are compared to those of Wada et al. 2006 (Icarus 180, 528-545) and to impact experiments performed in conjunction with Hayabusa 2. This work is supported in part by grants from the National Science Foundation under grant number AST1009579 and from the Office of Space Science of NASA under grant number NNX08AM39G. Part of this study resulted from discussions with the International Team (#202) sponsored by ISSI in Bern (Switzerland). Some simulations were performed on the YORP cluster administered by the Center for Theory and Computation of the Department of Astronomy at the University of Maryland in College Park and on the SIGGAM computer cluster hosted by the Côte d'Azur Observatory in Nice (France).

  5. Architecture and emplacement of flood basalt flow fields: case studies from the Columbia River Basalt Group, NW USA

    Science.gov (United States)

    Vye-Brown, C.; Self, S.; Barry, T. L.

    2013-03-01

    The physical features and morphologies of collections of lava bodies emplaced during single eruptions (known as flow fields) can be used to understand flood basalt emplacement mechanisms. Characteristics and internal features of lava lobes and whole flow field morphologies result from the forward propagation, radial spread, and cooling of individual lobes and are used as a tool to understand the architecture of extensive flood basalt lavas. The features of three flood basalt flow fields from the Columbia River Basalt Group are presented, including the Palouse Falls flow field, a small (8,890 km2, ˜190 km3) unit by common flood basalt proportions, and visualized in three dimensions. The architecture of the Palouse Falls flow field is compared to the complex Ginkgo and more extensive Sand Hollow flow fields to investigate the degree to which simple emplacement models represent the style, as well as the spatial and temporal developments, of flow fields. Evidence from each flow field supports emplacement by inflation as the predominant mechanism producing thick lobes. Inflation enables existing lobes to transmit lava to form new lobes, thus extending the advance and spread of lava flow fields. Minimum emplacement timescales calculated for each flow field are 19.3 years for Palouse Falls, 8.3 years for Ginkgo, and 16.9 years for Sand Hollow. Simple flow fields can be traced from vent to distal areas and an emplacement sequence visualized, but those with multiple-layered lobes present a degree of complexity that make lava pathways and emplacement sequences more difficult to identify.

  6. Miocene Basaltic Lava Flows and Dikes of the Intervening Area Between Picture Gorge and Steens Basalt of the CRBG, Eastern Oregon

    Science.gov (United States)

    Cahoon, E. B.; Streck, M. J.

    2016-12-01

    Mid-Miocene basaltic lavas and dikes are exposed in the area between the southern extent of the Picture Gorge Basalt (PGB) and the northern extent of Steens Basalt in a wide corridor of the Malheur National Forest, eastern Oregon. An approximate mid-Miocene age of sampled basaltic units is indicated by stratigraphic relationships to the 16 Ma Dinner Creek Tuff. Lavas provide an opportunity to extend and/or revise distribution areas of either CRBG unit and explore the petrologic transition between them. The PGB and the Steens Basalt largely represent geochemically distinct tholeiitic units of the CRBG; although each unit displays internal complexity. Lavas of PGB are relatively primitive (MgO 5-9 wt.%) while Steens Basalt ranges in MgO from >9 to 3 wt.% but both units are commonly coarsely porphyritic. Conversely, Steens Basalt compositions are on average more enriched in highly incompatible elements (e.g. Rb, Th) and relatively enriched in the lesser incompatible elements (e.g. Y, Yb) compared to the Picture Gorge basalts. These compositional signatures produce inclined and flat patterns on mantle-normalized incompatible trace element plots but with similar troughs and spikes, respectively. New compositional data from our study area indicate basaltic lavas can be assigned as PGB lava flows and dikes, and also to a compositional group chemically distinct between Steens Basalt and PGB. Distribution of lava flows with PGB composition extend this CRBG unit significantly south/southeast closing the exposure gap between PGB and Steens Basalt. We await data that match Steens Basalt compositions but basaltic lavas with petrographic features akin to Steens Basalt have been identified in the study area. Lavas of the transitional unit share characteristics with Upper Steens and Picture Gorge basalt types, but identify a new seemingly unique composition. This composition is slightly more depleted in the lesser incompatible elements (i.e. steeper pattern) on mantle normalized

  7. Consortium study of lunar meteorites Yamato-793169 and Asuka-881757: Geochemical evidence of mutual similarity, and dissimilarity versus other mare basalts

    Science.gov (United States)

    Warren, Paul H.; Lindstrom, Marilyn M.

    1993-01-01

    Compositions of bulk powders and separated minerals from two meteorites derived from the mare lava plains of the Earth's Moon, Yamato-793169 and Asuka-881757, indicate a remarkable degree of similarity to one another, and clearly favor lunar origin. However, these meteorites are unlike any previously studied lunar rock. In both cases, the bulk-rock TiO2 content is slightly greater than the level separating VLT from low-Ti mare basalt, yet the Sc content is much higher than previously observed except among high-Ti mare basalts. Conceivably, the Sc enrichment in A881757 reflects origin of this rock as a cumulate from a mare magma of 'normal' Sc content, but this seems unlikely. Mineral-separate data suggest that most of the Sc is in pyroxene, and a variety of evidence weighs against the cumulus hypothesis as a major cause for the high Sc. The remarkable similarity between Y793169 and A881757 suggests the possibility that they were derived from a single source crater on the Moon.

  8. Atmospheric Tides in Gale Crater, Mars

    Science.gov (United States)

    Guzewich, Scott D,; Newman, C. E; de la Torre Juarez, M.; Wilson, R. J.; Lemmon, M.; Smith, M. D.; Kahanpaa, H.; Harri, A.-M.

    2015-01-01

    Atmospheric tides are the primary source of daily air pressure variation at the surface of Mars. These tides are forced by solar heating of the atmosphere and modulated by the presence of atmospheric dust, topography, and surface albedo and thermal inertia. This results in a complex mix of sun-synchronous and nonsun- synchronous tides propagating both eastward and westward around the planet in periods that are integer fractions of a solar day. The Rover Environmental Monitoring Station on board the Mars Science Laboratory has observed air pressure at a regular cadence for over 1 Mars year and here we analyze and diagnose atmospheric tides in this pressure record. The diurnal tide amplitude varies from 26 to 63 Pa with an average phase of 0424 local true solar time, while the semidiurnal tide amplitude varies from 5 to 20 Pa with an average phase of 0929. We find that both the diurnal and semidiurnal tides in Gale Crater are highly correlated to atmospheric opacity variations at a value of 0.9 and to each other at a value of 0.77, with some key exceptions occurring during regional and local dust storms. We supplement our analysis with MarsWRF general circulation modeling to examine how a local dust storm impacts the diurnal tide in its vicinity. We find that both the diurnal tide amplitude enhancement and regional coverage of notable amplitude enhancement linearly scales with the size of the local dust storm. Our results provide the first long-term record of surface pressure tides near the martian equator.

  9. Surface modification of basalt with silane coupling agent on asphalt mixture moisture damage

    Energy Technology Data Exchange (ETDEWEB)

    Min, Yahong; Fang, Ying; Huang, Xiaojun; Zhu, Yinhui; Li, Wensheng [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Yuan, Jianmin [College of Materials Engineering, Hunan University, Changsha, 410082 (China); Tan, Ligang [College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082 (China); Wang, Shuangyin [State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China); Wu, Zhenjun, E-mail: wooawt@163.com [College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 (China)

    2015-08-15

    Graphical abstract: - Highlights: • A new silane coupling agent was synthesized based on KH570. • Basalt surface was modified using the new silane coupling agent. • Chemical bond between basalt and the new silane coupling agent was formed. • Asphalt mixture which used modified basalt show superior water stability. - Abstract: A new silane coupling agent was synthesized based on γ-(methacryloyloxy) propyltrimethoxysilane (KH570). The surface of basalt rocks was modified by KH570 and the new silane coupling agent (NSCA), and the interfacial interaction between silane coupling agent and basalt was also studied. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis showed that the silane coupling agent molecule bound strongly with basalt rocks. Scanning electronic microscopy (SEM) observation showed that a thin layer of coupling agent was formed on the surface of modified basalt. The boiling test and immersion Marshall test confirmed that the moisture sensitivity of basalt modified with the new silane coupling agent increased more significantly than that untreated and treated with KH570. The Retained Marshall Strength of basalt modified with the new coupling agent increased from 71.74% to 87.79% compared with untreated basalt. The results indicated that the new silane coupling agent played an important role in improving the interfacial performance between basalt and asphalt.

  10. Investigation on mechanical properties of basalt composite fabrics (experiment study)

    Science.gov (United States)

    Talebi Mazraehshahi, H.; Zamani, H.

    2010-06-01

    To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1). Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2). Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3). Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4). Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one material with

  11. Investigation on mechanical properties of basalt composite fabrics (experiment study

    Directory of Open Access Journals (Sweden)

    Talebi Mazraehshahi H.

    2010-06-01

    Full Text Available To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1. Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2. Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3. Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4. Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one

  12. Basalt characterization by means of nuclear and electrical well logging techniques. Case study from Southern Syria

    International Nuclear Information System (INIS)

    Asfahani, Jamal

    2011-01-01

    Nuclear well logging, including natural gamma ray, density, and neutron-porosity techniques are used with electrical well logging of long and short normal techniques to characterize the basaltic areas largely extended in Southern Syria. Statistical analysis approach with the threshold concept has been adapted for such characterization, where four kinds of basalt have been identified: very hard basalt, hard basalt, fractured basalt, and basalt alteration products. The spectrometric gamma technique has also been applied on the retrieved rock samples in order to determine the radioactive content (eU, eTh, and K%) of the basaltic section in the study area. No radioactive anomalies have been detected, the radioactive values are normal and in the expected range.

  13. A crater and its ejecta: An interpretation of Deep Impact

    Science.gov (United States)

    Holsapple, Keith A.; Housen, Kevin R.

    2007-03-01

    We apply recently updated scaling laws for impact cratering and ejecta to interpret observations of the Deep Impact event. An important question is whether the cratering event was gravity or strength-dominated; the answer gives important clues about the properties of the surface material of Tempel 1. Gravity scaling was assumed in pre-event calculations and has been asserted in initial studies of the mission results. Because the gravity field of Tempel 1 is extremely weak, a gravity-dominated event necessarily implies a surface with essentially zero strength. The conclusion of gravity scaling was based mainly on the interpretation that the impact ejecta plume remained attached to the comet during its evolution. We address that feature here, and conclude that even strength-dominated craters would result in a plume that appeared to remain attached to the surface. We then calculate the plume characteristics from scaling laws for a variety of material types, and for gravity and strength-dominated cases. We find that no model of cratering alone can match the reported observation of plume mass and brightness history. Instead, comet-like acceleration mechanisms such as expanding vapor clouds are required to move the ejected mass to the far field in a few-hour time frame. With such mechanisms, and to within the large uncertainties, either gravity or strength craters can provide the levels of estimated observed mass. Thus, the observations are unlikely to answer the questions about the mechanical nature of the Tempel 1 surface.

  14. Detection and characterization of buried lunar craters with GRAIL data

    Science.gov (United States)

    Sood, Rohan; Chappaz, Loic; Melosh, Henry J.; Howell, Kathleen C.; Milbury, Colleen; Blair, David M.; Zuber, Maria T.

    2017-06-01

    We used gravity mapping observations from NASA's Gravity Recovery and Interior Laboratory (GRAIL) to detect, characterize and validate the presence of large impact craters buried beneath the lunar maria. In this paper we focus on two prominent anomalies detected in the GRAIL data using the gravity gradiometry technique. Our detection strategy is applied to both free-air and Bouguer gravity field observations to identify gravitational signatures that are similar to those observed over buried craters. The presence of buried craters is further supported by individual analysis of regional free-air gravity anomalies, Bouguer gravity anomaly maps, and forward modeling. Our best candidate, for which we propose the informal name of Earhart Crater, is approximately 200 km in diameter and forms part of the northwestern rim of Lacus Somniorum, The other candidate, for which we propose the informal name of Ashoka Anomaly, is approximately 160 km in diameter and lies completely buried beneath Mare Tranquillitatis. Other large, still unrecognized, craters undoubtedly underlie other portions of the Moon's vast mare lavas.

  15. East Part of Sapas Mons with Flooded Crater

    Science.gov (United States)

    1991-01-01

    This Magellan image centered near 9.6 degrees north latitude, 189.5 degrees east longitude of an area 140 kilometers (87 miles) by 110 kilometers (68 miles) covers part of the eastern flank of the volcano Sapas Mons on the western edge of Atla Regio. The bright lobate features along the southern and the western part of the image, oriented in northeast to southwest directions, are lava flows that are rough at the 12.6 centimeter wavelength of the radar. These flows range in width from 5 kilometers to 25 kilometers (3 to 16 miles) with lengths of 50 kilometers to 100 kilometers (31 to 62 miles), extending off the area shown here. Additional radar-dark (smooth) flows are also present. The radar-bright linear structures in the northwest part of the image are interpreted to be faults and fractures possibly associated with the emplacement of magma in the subsurface. Located near the center of the image is a 20 kilometer (12 mile) diameter impact crater. This crater is superimposed on a northeast/southwest trending fracture while the southern part of the crater's ejecta blanket is covered by a 6 kilometer (4 mile) wide radar-bright lava flow. These relations indicate that the crater post dates an episode of fracturing and is older than the lava flows covering its southern edge. This is one of only a few places on Venus in which an impact crater is seen to be covered by volcanic deposits.

  16. Measuring impact crater depth throughout the solar system

    Science.gov (United States)

    Robbins, Stuart J.; Watters, Wesley A.; Chappelow, John E.; Bray, Veronica J.; Daubar, Ingrid J.; Craddock, Robert A.; Beyer, Ross A.; Landis, Margaret E.; Ostrach, Lillian; Tornabene, Livio L.; Riggs, Jamie D.; Weaver, Brian P.

    2018-01-01

    One important, almost ubiquitous, tool for understanding the surfaces of solid bodies throughout the solar system is the study of impact craters. While measuring a distribution of crater diameters and locations is an important tool for a wide variety of studies, so too is measuring a crater's “depth.” Depth can inform numerous studies including the strength of a surface and modification rates in the local environment. There is, however, no standard data set, definition, or technique to perform this data‐gathering task, and the abundance of different definitions of “depth” and methods for estimating that quantity can lead to misunderstandings in and of the literature. In this review, we describe a wide variety of data sets and methods to analyze those data sets that have been, are currently, or could be used to derive different types of crater depth measurements. We also recommend certain nomenclature in doing so to help standardize practice in the field. We present a review section of all crater depths that have been published on different solar system bodies which shows how the field has evolved through time and how some common assumptions might not be wholly accurate. We conclude with several recommendations for researchers which could help different data sets to be more easily understood and compared.

  17. Water in the oceanic lithosphere: Salt Lake Crater xenoliths, Oahu, Hawaii

    Science.gov (United States)

    Peslier, A. H.; Bizimis, M.

    2010-12-01

    Water can be present in nominally anhydrous minerals of peridotites in the form of hydrogen bonded to structural oxygen. Such water in the oceanic upper mantle could have a significant effect on its physical and chemical properties. However, the water content of the MORB source has been inferred indirectly from the compositions of basalts. Direct determinations on abyssal peridotites are scarce because they have been heavily hydrothermally altered. Here we present the first water analyses of minerals from spinel peridotite xenoliths of Salt Lake Crater, Oahu, Hawaii, which are exceptionally fresh. These peridotites are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. A few have unradiogenic Os and radiogenic Hf isotopes and may be fragments of an ancient ( 2 Ga) depleted and recycled lithosphere. Water contents in olivine (Ol), orthopyroxene (Opx), and clinopyroxene (Cpx) were determined by FTIR spectrometry. Preliminary H_{2}O contents show ranges of 8-10 ppm for Ol, 151-277 ppm for Opx, and 337-603 ppm for Cpx. Reconstructed bulk rock H_{2}O contents range from 88-131 ppm overlapping estimates for the MORB source. Water contents between Ol minerals of the same xenolith are heterogeneous and individual OH infrared bands vary within a mineral with lower 3230 cm^{-1} and higher 3650-3400 cm^{-1} band heights from core to edge. This observation suggests disturbance of the hydrogen in Ol likely occurring during xenolith entrainment to the surface. Pyroxene water contents are higher than most water contents in pyroxenes from continental peridotite xenoliths and higher than those of abyssal peridotites. Cpx water contents decrease with increasing degree of depletion (e.g. increasing Fo in Ol and Cr# in spinel) consistent with an incompatible behavior of water. However Cpx water contents also show a positive correlation with LREE/HREE ratios and LREE concentrations consistent with refertilization. Opx

  18. King's Bowl Pit Crater, Lava Field and Eruptive Fissure, Idaho - A Multipurpose Volcanic Planetary Analog

    Science.gov (United States)

    Hughes, S. S.; Garry, B.; Kobs-Nawotniak, S. E.; Sears, D. W. G.; Borg, C.; Elphic, R. C.; Haberle, C. W.; Kobayashi, L.; Lim, D. S. S.; Sears, H.; Skok, J. R.; Heldmann, J. L.

    2014-12-01

    King's Bowl (KB) and its associated eruptive fissure and lava field on the eastern Snake River Plain, is being investigated by the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team as a planetary analog to similar pits on the Moon, Mars and Vesta. The 2,220 ± 100 BP basaltic eruption in Craters of the Moon National Monument and Preserve represents early stages of low shield growth, which was aborted when magma supply was cut off. Compared to mature shields, KB is miniscule, with ~0.02 km3 of lava over ~3 km2, yet the ~6 km long series of fissures, cracks and pits are well-preserved for analog studies of volcanic processes. The termination of eruption was likely related to proximity of the 2,270 ± 50 BP eruption of the much larger Wapi lava field (~5.5 km3 over 325 km2 area) on the same rift. Our investigation extends early work by R. Greeley and colleagues, focusing on imagery, compositional variations, ejecta distribution, dGPS profiles and LiDAR scans of features related to: (1) fissure eruptions - spatter ramparts, cones, feeder dikes, extension cracks; (2) lava lake formation - surface morphology, squeeze-ups, slab pahoehoe lava mounds, lava drain-back, flow lobe overlaps; and (3) phreatic steam blasts - explosion pits, ejecta blankets of ash and blocks. Preliminary results indicate multiple fissure eruptions and growth of a basin-filled lava lake up to ~ 10 m thick with outflow sheet lava flows. Remnant mounds of original lake crust reveal an early high lava lake level, which subsided as much as 5 m as the molten interior drained back into the fissure system. Rapid loss of magma supply led to the collapse of fissure walls allowing groundwater influx that triggered multiple steam blasts along at least 500 m. Early blasts occurred while lake magma pressure was still high enough to produce squeeze-ups when penetrated by ejecta blocks. The King's Bowl pit crater exemplifies processes of a small, but highly energetic

  19. Water in the Oceanic Lithosphere: Salt Lake Crater Xenoliths, Oahu, Hawaii

    Science.gov (United States)

    Peslier, Anne H.; Bizimis, Michael

    2010-01-01

    Water can be present in nominally anhydrous minerals of peridotites in the form of hydrogen bonded to structural oxygen. Such water in the oceanic upper mantle could have a significant effect on its physical and chemical properties. However, the water content of the MORB source has been inferred indirectly from the compositions of basalts. Direct determinations on abyssal peridotites are scarce because they have been heavily hydrothermally altered. Here we present the first water analyses of minerals from spinel peridotite xenoliths of Salt Lake Crater, Oahu, Hawaii, which are exceptionally fresh. These peridotites are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. A few have unradiogenic Os and radiogenic Hf isotopes and may be fragments of an ancient (2 Ga) depleted and recycled lithosphere. Water contents in olivine (Ol), orthopyroxene (Opx), and clinopyroxene (Cpx) were determined by FTIR spectrometry. Preliminary H_{2}O contents show ranges of 8-10 ppm for Ol, 151-277 ppm for Opx, and 337-603 ppm for Cpx. Reconstructed bulk rock H_{2}O contents range from 88-131 ppm overlapping estimates for the MORB source. Water contents between Ol minerals of the same xenolith are heterogeneous and individual OH infrared bands vary within a mineral with lower 3230 cm^{-1} and higher 3650-3400 cm^{-1} band heights from core to edge. This observation suggests disturbance of the hydrogen in Ol likely occurring during xenolith entrainment to the surface. Pyroxene water contents are higher than most water contents in pyroxenes from continental peridotite xenoliths and higher than those of abyssal peridotites. Cpx water contents decrease with increasing degree of depletion (e.g. increasing Fo in Ol and Cr# in spinel) consistent with an incompatible behavior of water. However Cpx water contents also show a positive correlation with LREE/HREE ratios and LREE concentrations consistent with refertilization. Opx water

  20. Mars weathering analogs - Secondary mineralization in Antarctic basalts

    Science.gov (United States)

    Berkley, J. L.

    1982-01-01

    Alkalic basalt samples from Ross Island, Antarctica, are evaluated as terrestrial analogs to weathered surface materials on Mars. Secondary alteration in the rocks is limited to pneumatolytic oxidation of igneous minerals and glass, rare groundmass clay and zeolite mineralization, and hydrothermal minerals coating fractures and vesicle surfaces. Hydrothermal mineral assemblages consist mainly of K-feldspar, zeolites (phillipsite and chabazite), calcite, and anhydrite. Low alteration rates are attributed to cold and dry environmental factors common to both Antarctica and Mars. It is noted that mechanical weathering (aeolian abrasion) of Martian equivalents to present Antarctic basalts would yield minor hydrothermal minerals and local surface fines composed of primary igneous minerals and glass but would produce few hydrous products, such as palagonite, clay or micas. It is thought that leaching of hydrothermal vein minerals by migrating fluids and redeposition in duricrust deposits may represent an alternate process for incorporating secondary minerals of volcanic origin into Martian surface fines.

  1. Petrogeochemistry of Mesozoic basaltic volcanics in Daqingshan area

    International Nuclear Information System (INIS)

    Li Xiaoguang; Li Ziying; Wei Sanyuan; Qi Da'neng

    2009-01-01

    Through the discussion on petrogeochemistry of Later Mesozoic basaltic volcanics in Daqingshan Basin in Manzhouli area, combined with field observation and the predecessors' study, its magma evolution,genesis and diagenetic structural environment are discussed, and some suggestion are provided for the further work. Basaltic magma in this area is believed to be derived from mantle with incompatible elements which were later participated by some crustal materials. It is a partially melting product of mantle by early metasomatized fluid under lithosphere extension. Through petrogeochemical analysis of the volcanics and the contrast to the adjacent uranium-producing volcanics, it is concluded that this region has structural environment to form magma evolution series which are more favorable for volcanic hydrothermal-type uranium and polymetallic mineralization. (authors)

  2. Americium migration in basalt and implications to repository risk analysis

    International Nuclear Information System (INIS)

    Rickert, P.G.

    1980-01-01

    Experiments were performed with americium as a minor component in groundwater. Batch adsorption, migration through column, and filtration experiments were performed. It was determined in batch experiments that americium is strongly adsorbed from solution. It was determined with filtration experiments that large percentages of the americium concentrations suspended by the contact solutions in batch experiments and suspended by the infiltrating groundwater in migration experiments were associated with particulate. Filtration was determined to be the primary mode of removal of americium from infiltrating groundwater in a column of granulated basalt (20 to 50 mesh) and an intact core of permeable basalt. Fractionally, 0.46 and 0.22 of the americium component in the infiltrating groundwater was transported through the column and core respectively. In view of these filtration and migration experiment results, the concept of K/sub d/ in the chromatographic sense is meaningless for predicting americium migration in bedrock by groundwater transport at near neutral pH

  3. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    primitive basalts and trachybasalts but also more evolved samples from the retroarc region and the larger volcanoes Payún Matrú and Payún Liso are presented. The samples cover a broad range of compositions from intraplate lavas similar to ocean island basalts to arc andesites. A common feature found...... are isotopically similar to the Andean Southern Volcanic Zone arc rocks and their mantle source possibly resembled the source of South Atlantic N-MORB prior to addition of fluids and melts from the subduction channel. However, it must have been more enriched than the estimates of depleted upper mantle from...... the lithosphere is thinnest and possibly in areas of elevated mantle temperatures. The pyroxenite melts formed at deeper levels react with the surrounding peridotite and thereby changes composition leading to eruption of melts which experienced variable degrees of melt-peridotite interaction. This can presumably...

  4. Environmental resistance and mechanical performance of basalt and glass fibers

    International Nuclear Information System (INIS)

    Wei Bin; Cao Hailin; Song Shenhua

    2010-01-01

    The treated basalt and glass fibers with sodium hydroxide and hydrochloric acid solutions for different times were analyzed, respectively. This paper summarized the mass loss ratio and the strength maintenance ratios of the fibers after treatment. The fibers' surface corrosion morphologies were characterized using scanning electron microscopy and their compositions were detected using energy dispersive X-ray spectroscopy. The acid resistance was much better than the alkali resistance for the basalt fibers. Nevertheless, for the glass fibers the situation is different: the acid resistance was almost the same as the alkali resistance. Among the two types of aqueous environments evaluated, the alkali solution is the most aggressive to the fibers' surface. The possible corrosion mechanisms are revealed.

  5. Imaging the Buried Chicxulub Crater with Gravity Gradients and Cenotes

    Science.gov (United States)

    Hildebrand, A. R.; Pilkington, M.; Halpenny, J. F.; Ortiz-Aleman, C.; Chavez, R. E.; Urrutia-Fucugauchi, J.; Connors, M.; Graniel-Castro, E.; Camara-Zi, A.; Vasquez, J.

    1995-09-01

    Differing interpretations of the Bouguer gravity anomaly over the Chicxulub crater, Yucatan Peninsula, Mexico, have yielded diameter estimates of 170 to 320 km. Knowing the crater's size is necessary to quantify the lethal perturbations to the Cretaceous environment associated with its formation. The crater's size (and internal structure) is revealed by the horizontal gradient of the Bouguer gravity anomaly over the structure, and by mapping the karst features of the Yucatan region. To improve our resolution of the crater's gravity signature we collected additional gravity measurements primarily along radial profiles, but also to fill in previously unsurveyed areas. Horizontal gradient analysis of Bouguer gravity data objectively highlights the lateral density contrasts of the impact lithologies and suppresses regional anomalies which may obscure the gravity signature of the Chicxulub crater lithologies. This gradient technique yields a striking circular structure with at least 6 concentric gradient features between 25 and 85 km radius. These features are most distinct in the southwest probably because of denser sampling of the gravity field. Our detailed profiles detected an additional feature and steeper gradients (up to 5 mGal/km) than the original survey. We interpret the outer four gradient maxima to represent concentric faults in the crater's zone of slumping as is also revealed by seismic reflection data. The inner two probably represent the margin of the central uplift and the peak ring and or collapsed transient cavity. Radial gradients in the SW quadrant over the inferred ~40 km-diameter central uplift (4) may represent structural "puckering" as revealed at eroded terrestrial craters. Gradient features related to regional gravity highs and lows are visible outside the crater, but no concentric gradient features are apparent at distances > 90 km radius. The marginal gradient features may be modelled by slump faults as observed in large complex craters on

  6. A new basaltic glass microanalytical reference material for multiple techniques

    Science.gov (United States)

    Wilson, Steve; Koenig, Alan; Lowers, Heather

    2012-01-01

    The U.S. Geological Survey (USGS) has been producing reference materials since the 1950s. Over 50 materials have been developed to cover bulk rock, sediment, and soils for the geological community. These materials are used globally in geochemistry, environmental, and analytical laboratories that perform bulk chemistry and/or microanalysis for instrument calibration and quality assurance testing. To answer the growing demand for higher spatial resolution and sensitivity, there is a need to create a new generation of microanalytical reference materials suitable for a variety of techniques, such as scanning electron microscopy/X-ray spectrometry (SEM/EDS), electron probe microanalysis (EPMA), laser ablation inductively coupled mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS). As such, the microanalytical reference material (MRM) needs to be stable under the beam, be homogeneous at scales of better than 10–25 micrometers for the major to ultra-trace element level, and contain all of the analytes (elements or isotopes) of interest. Previous development of basaltic glasses intended for LA-ICP-MS has resulted in a synthetic basaltic matrix series of glasses (USGS GS-series) and a natural basalt series of glasses (BCR-1G, BHVO-2G, and NKT-1G). These materials have been useful for the LA-ICP-MS community but were not originally intended for use by the electron or ion beam community. A material developed from start to finish with intended use in multiple microanalytical instruments would be useful for inter-laboratory and inter-instrument platform comparisons. This article summarizes the experiments undertaken to produce a basalt glass reference material suitable for distribution as a multiple-technique round robin material. The goal of the analytical work presented here is to demonstrate that the elemental homogeneity of the new glass is acceptable for its use as a reference material. Because the round robin exercise is still underway, only

  7. Basaltic Shergottite NWA 856: Differentiation of a Martian Magma

    Science.gov (United States)

    Ferdous, J.; Brandon, A. D.; Peslier, A. H.; Pirotte, Z.

    2016-01-01

    NWA 856 or Djel Ibone, is a basaltic shergottite discovered as a single stone of 320 g in South Morocco in April, 2001. This meteorite is fresh, i.e. shows minimal terrestrial weathering for a desert find. No shergottite discovered in North Africa can be paired with NWA 856. The purpose of this study is to constrain its crystallization history using textural observations, crystallization sequence modeling and in-situ trace element analysis in order to understand differentiation in shergottite magmatic systems.

  8. Rock mass deformation properties of closely jointed basalt

    International Nuclear Information System (INIS)

    Kim, K.; Cramer, M.L.

    1982-12-01

    The deformational behavior of the Columbia River basalt is being investigated as part of a comprehensive site characterization program intended to determine the feasibility of constructing a nuclear waste repository in basalt at Hanford, Washington. Direct field measurements were conducted in a 2-m cube of basalt to obtain truly representative rock mass deformation properties. Load was applied to the test block in three orthogonal directions through the use of flat jacks in two perpendicular planes and a cable anchor system in the third. This configuration allowed the block to be placed in a simulated triaxial stress state at stress levels up to 12.5 MPa. The deformation at the center of the test block was monitored through the use of an optical measurement system developed for this project. The results indicate that the vertically oriented columnar joints have a significant influence on the deformation behavior of the basalt. The modulus in the direction parallel to the column axis was approx. 30 GPa, while the modulus value perpendicular to the columns was approx. 20 GPa. Laboratory measurements of intact specimens taken from this area yielded a value of 80 GPa with no indication of anisotropy. Hysteresis was observed in all loading cycles, but was distinctly more pronounced perpendicular to the column axis, indicative of significant joint displacement in this direction. The results of this test represent the first true rock mass modulus data obtained in closely jointed rock on a large scale. These measurement methods have eliminated many of the ambiguities associated with borehole jacking and surface measurement techniques

  9. Crater Ejecta by Day and Night

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 24 June 2004 This pair of images shows a crater and its ejecta. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude -9, Longitude 164.2 East (195.8 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project

  10. Meridiani Crater in Day and Night

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 14 June 2004 This pair of images shows crater ejecta in the Terra Meridiani region. Day/Night Infrared Pairs The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top. Infrared image interpretation Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark. Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images. Image information: IR instrument. Latitude -1.6, Longitude 4.1 East (355.9 West). 100 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in

  11. Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

    Science.gov (United States)

    Bacon, Charles R.; Lanphere, Marvin A.

    2006-01-01

    Geologic mapping, K-Ar, and 40Ar/39Ar age determinations, supplemented by paleomagnetic measurements and geochemical data, are used to quantify the Quaternary volcanic history of the Crater Lake region in order to define processes and conditions that led to voluminous explosive eruptions. The Cascade arc volcano known as Mount Mazama collapsed during its climactic eruption of ∼50 km3 of mainly rhyodacitic magma ∼7700 yr ago to form Crater Lake caldera. The Mazama edifice was constructed on a Pleistocene silicic lava field, amidst monogenetic and shield volcanoes ranging from basalt to andesite similar to parental magmas for Mount Mazama. Between 420 ka and 35 ka, Mazama produced medium-K andesite and dacite in 2:1 proportion. The edifice was built in many episodes; some of the more voluminous occurred approximately coeval with volcanic pulses in the surrounding region, and some were possibly related to deglaciation following marine oxygen isotope stages (MIS) 12, 10, 8, 6, 5.2, and 2. Magmas as evolved as dacite erupted many times, commonly associated with or following voluminous andesite effusion. Establishment of the climactic magma chamber was under way when the first preclimactic rhyodacites vented ca. 27 ka. The silicic melt volume then grew incrementally at an average rate of 2.5 km3 k.y.−1 for nearly 20 k.y. The climactic eruption exhausted the rhyodacitic magma and brought up crystal-rich andesitic magma, mafic cumulate mush, and wall-rock granodiorite. Postcaldera volcanism produced 4 km3 of andesite during the first 200–500 yr after collapse, followed at ca. 4800 yr B.P. by 0.07 km3 of rhyodacite. The average eruption rate for all Mazama products was ∼0.4 km3 k.y.−1, but major edifice construction episodes had rates of ∼0.8 km3 k.y.−1. The long-term eruption rate for regional monogenetic and shield volcanoes was d∼0.07 km3 k.y.−1, but only ∼0.02 km3 k.y.−1 when the two major shields are excluded. Plutonic xenoliths and evidence for

  12. Interim reclamation report, Basalt Waste Isolation project: Boreholes, 1989

    International Nuclear Information System (INIS)

    Brandt, C.A.; Rickard, W.H. Jr.; Hefty, M.G.

    1990-03-01

    In 1968, a program was started to assess the feasibility of storing Hanford Site defense waste in deep caverns constructed in basalt. This program was expanded in 1976 to include investigations of the Hanford Site as a potential location for a mined commercial nuclear waste repository. An extensive site characterization program was begun to determine the feasibility of using the basalts beneath the Hanford Site for the repository. Site research focused primarily on determining the direction and speed of groundwater movement, the uniformity of basalt layers, and tectonic stability. Some 98 boreholes were sited, drilled, deepened, or modified by BWIP between 1977 and 1988 to test the geologic properties of the Site. On December 22, 1987, President Reagan signed into law the Nuclear Waste Policy Amendments Act of 1987, which effectively stopped all repository-related activities except reclamation of disturbed lands at the Hanford Site. This report describes the development of the reclamation program for the BWIP boreholes, its implementation, and preliminary estimates of its success. The goal of the reclamation program is to return sites disturbed by the repository program as nearly as practicable to their original conditions using native plant species. 48 refs., 28 figs., 14 tabs

  13. The Age of Rift-Related Basalts in East Antarctica

    Science.gov (United States)

    Leitchenkov, G. L.; Belyatsky, B. V.; Kaminsky, V. D.

    2018-01-01

    The Lambert Rift, which is a large intracontinental rift zone in East Antarctica, developed over a long period of geological time, beginning from the Late Paleozoic, and its evolution was accompanied by magmatic activity. The latest manifestation of magmatism is eruption of alkaline olivine-leucite basalts on the western side of the Lambert Rift; Rb-Sr dating referred its time to the Middle Eocene, although its genesis remained vague. In order to solve this problem, we found geochronometer minerals in basaltic samples and 68 apatite grains appeared to be suitable for analysis. Their ages and ages of host basalts, determined by the U-Pb local method on the SIMS SHRIMP-II, were significantly different (323 ± 31 Ma) from those assumed earlier. This age corresponds to the earliest stage of crustal extension in East Antarctica and to most of Gondwana. The new data crucially change the ideas about the evolution of Lambert Rift and demonstrate the ambiguity of K-Ar dates of the alkali effusive formed under long-term rifting.

  14. Basalt Waste Isolation Project. Annual report, fiscal year 1980

    International Nuclear Information System (INIS)

    1980-11-01

    During this fiscal year the information available in the fields of geology and hydrology of the Columbia Plateau was consolidated and two reports were issued summarizing this information. In addition, the information on engineered barriers was consolidated and a report summarizing the research to date on waste package development and design of borehole seals was prepared. The waste package studies, when combined with the hydrologic integration, revealed that even under extreme disruptive conditions, a repository in basalt with appropriately designed waste packages can serve as an excellent barrier for containment of radionuclides for the long periods of time required for waste isolation. On July 1, 1980, the first two heater tests at the Near-Surface Test Facility were started and have been successfully operated to this date. The papers on the Near-Surface Test Facility section of this report present the results of the equipment installed and the preliminary results of the testing. In October 1979, the US Department of Energy selected the joint venture of Kaiser Engineers/Parsons Brinckerhoff Quade and Douglas, Inc., to be the architect-engineer to produce a conceptual design of a repository in basalt. During the year, this design has progressed and concept selection has now been completed. This annual report presents a summary of the highlights of the work completed during fiscal year 1980. It is intended to supplement and summarize the nearly 200 papers and reports that have been distributed to date as a part of the Basalt Waste Isolation Project studies

  15. Dissolution of basaltic glass in seawater: Mechanism and rate

    International Nuclear Information System (INIS)

    Crovisier, J.L.; Honnorez, J.; Eberhart, J.P.

    1987-01-01

    Basaltic glasses are considered as natural analogues for nuclear waste glasses. Thermodynamic computer codes used to evaluate long term behavior of both nuclear waste and basaltic glasses require the knowledge of the dissolution mechanism of the glass network. The paper presents the results of a series of experiments designed to study the structure and chemical composition of alteration layers formed on the surface of artificial tholeiitic glass altered in artificial seawater. Experiments were performed at 60 degree C, 1 bar and 350 bars in non-renewed conditions. A natural sample from Palagonia (Sicily) has been studied by electron microscopy and comparison between natural and experimental palagonitic layers is made. The behavior of dissolved silica during experiments, and both the structure and the chemical composition of the palagonitic layers, indicate that they form by precipitation of secondary minerals from solution after a total breakdown of the glassy network, i.e., congruent dissolution of the glass. Hence the dissolution equation necessary for thermodynamic modelling of basaltic glass dissolution in seawater at low temperature must be written as a simple stoichiometric process. These experiments indicate that the transformation of glass to palagonitic material is not isovolumetric. Hence it is preferable to use Fe or Ti as conservative elements for chemical budget calculations

  16. Characterization of iron-enriched synthetic basalt for transuranic containment

    International Nuclear Information System (INIS)

    Flinn, J.E.; Henslee, S.P.; Kelsey, P.V.; Tallman, R.L.; Welch, J.M.

    1980-01-01

    In the slagging pyrolytic incineration process, combustibles are burned and noncombustibles, including metals, are oxidized into a molten , an electromelter, where the molten slag, with further processing conducted in a heated tundish, e.g. is allowed to homogenize (within a reasonable time period) and then cast into large, cylindrical metal containers. Analyses of Idaho National Engineering Laboratory waste slags show them similar in composition and appearance to natural basalts, but rich in iron. The electromelt process and the resulting iron-rich castings offer great promise for rendering nuclear waste into a stable form. The process offers great flexibility with regard to both compositional variation of the incoming waste and the high rates at which the waste can be introduced and cast. The cast product, a fine-grained basalt-like material, shows excellent homogeneity with little or no reaction to the steel containment. The preliminary mechanical and chemical durability data show the form to have adequate containment properties for TRU waste. However, work presently underway to improve these properties through additives and controlled cooling cycles has greatly enhanced the durability of the waste form. Furthermore, recent evidence indicates that divalent iron (Fe 2+ ) included in the crystalline phases of granites and basalts imparts a resistance to leaching of uranium and other actinide ions

  17. The Links Between Target Properties and Layered Ejecta Craters in Acidalia and Utopia Planitiae Mars

    Science.gov (United States)

    Jones, E.; Osinski, G. R.

    2013-08-01

    Layered ejecta craters on Mars may form from excavation into subsurface volatiles. We examine a new catalogue of martian craters to decipher differences between the single- and double-layered ejecta populations in Acidalia and Utopia.

  18. Automated Detection of Craters in Martian Satellite Imagery Using Convolutional Neural Networks

    Science.gov (United States)

    Norman, C. J.; Paxman, J.; Benedix, G. K.; Tan, T.; Bland, P. A.; Towner, M.

    2018-04-01

    Crater counting is used in determining surface age of planets. We propose improvements to martian Crater Detection Algorithms by implementing an end-to-end detection approach with the possibility of scaling the algorithm planet-wide.

  19. Parameters critical to the morphology of fluidization craters

    Science.gov (United States)

    Siegal, B. S.; Gold, D. P.

    1973-01-01

    In order to study further the role of fluidization on the moon, a laboratory investigation was undertaken on two particulate material size fractions to determine the effect of variables, such as, duration of gas streaming, gas pressure, and 'regolith' thickness on the morphology of fluidization craters. A 3.175-mm cylindrical vent was used to simulate a gas streaming conduit. Details of the fluidization chamber are discussed together with questions of experimental control, aspects of nomenclature, crater measurements, and the effect of variables.

  20. Extreme Access & Lunar Ice Mining in Permanently Shadowed Craters Project

    Science.gov (United States)

    Mueller, Robert P.

    2014-01-01

    Results from the recent LCROSS mission in 2010, indicate that H2O ice and other useful volatiles such as CO, He, and N are present in the permanently shadowed craters at the poles of the moon. However, the extreme topography and steep slopes of the crater walls make access a significant challenge. In addition temperatures have been measured at 40K (-233 C) so quick access and exit is desirable before the mining robot cold soaks. The Global Exploration Roadmap lists extreme access as a necessary technology for Lunar Exploration.

  1. The seismic expression and hydrocarbon potential of subsurface impact craters

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, R.; Westbroek, H.H.; Lawton, D. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    1995-12-31

    The seismic characteristics of meteorite impact craters and their potential as oil and gas reservoirs were discussed. Seismic data from James River, Alberta, in the Western Canada Sedimentary Basin show subsurface anomalies to be meteorite impact structures. The White Valley structure in Saskatchewan has similar features and seismic anomalies indicate that it too could be a meteorite impact structure, although other possibilities have been proposed. Other impact structures in western Canada such as the Steen River structure and the Viewfield crater have or are producing hydrocarbons. 5 refs., 2 figs.

  2. Geomorphometric analysis of selected Martian craters using polar coordinate transformation

    Science.gov (United States)

    Magyar, Zoltán; Koma, Zsófia; Székely, Balázs

    2016-04-01

    Centrally symmetric landform elements are very common features on the surface of the planet Mars. The most conspicuous ones of them are the impact craters of various size. However, a closer look on these features reveals that they show often asymmetric patterns as well. These are partially related to the geometry of the trajectory of the impacting body, but sometimes it is a result of surface processes (e.g., freeze/thaw cycles, mass movements). Geomorphometric studies have already been carried out to reveal these pecularities. Our approach, the application of polar coordinate transformation (PCT) very sensitively enhances the non-radial and non-circular shapes. We used digital terrain models (DTMs) derived from the ESA Mars Express HRSC imagery. The original DTM or its derivatives (e.g. slope angle or aspect) are PCT transformed. We analyzed the craters inter alia with scattergrams in polar coordinates. The resulting point cloud can be used directly for the analysis, but in some cases an interpolation should be applied to enhance certain non-circular features (especially in case of smaller craters). Visual inspection of the crater slopes, coloured by the aspect, reveals smaller features. Some of them are processing artefacts, but many of them are related to local undulations in the topography or indications of mass movements. In many cases the undulations of the crater rim are due to erosional processes. The drawbacks of the technology are related to the uneven resolution of the projected image: features in the crater centre should be left out from the analysis because PCT has a low resolution around the projection center. Furthermore, the success of the PCT depends on the correct definition of the projection centre: erroneously centered images are not suitable for analysis. The PCT transformed images are also suitable for radial averaging and calculation of standard deviations, resulting in typical, comparable craters shapes. These studies may lead to a deeper

  3. Ceres' intriguing Occator crater and its faculae: formation and evolution

    Science.gov (United States)

    Buczkowski, D.; Scully, J. E. C.; Bowling, T.; Bu, C.; Castillo, J. C.; Jaumann, R.; Longobardo, A.; Nathues, A.; Neesemann, A.; Palomba, E.; Platz, T.; Quick, L. C.; Raponi, A.; Raymond, C. A.; Ruesch, O.; Russell, C. T.; Schenk, P.; Stein, N.

    2017-12-01

    Since March 2015, the Dawn spacecraft has orbited and explored Ceres, which is a dwarf planet and the largest object in the asteroid belt (radius 470 km). One of the most intriguing features on Ceres' surface is Occator crater, a 92-km-diameter impact crater that contains distinctive bright spots, called faculae, within its floor (Nathues et al., 2015; Russell et al., 2016; Schenk et al., 2017). Occator crater has been dated to 20-30 million years old (Nathues et al., 2017; Neesemann et al., 2017). The single scattering albedo of Occator's faculae is 0.67-0.80, which is greater than Ceres' average single scattering albedo of 0.09-0.11 (Li et al., 2016). The central facula is named Cerealia Facula, and is located in a 9 km wide and 700 m deep pit. There are also multiple additional faculae in the eastern crater floor, which are named the Vinalia Faculae. The faculae are mostly composed of sodium carbonate, are distinct from Ceres' average surface composition and are proposed to be the solid residues of crystallized brines (De Sanctis et al., 2016). The presence of such bright, apparently fresh, material on the surface of a dwarf planet that is billions of years old is intriguing, and indicates that active processes involving brines occurred within the geologically recent past. The Dawn Science Team has investigated whether the processes that formed the crater and the faculae are entirely endogenic, entirely exogenic or a combination of both. For example, the extensive lobate materials within the crater floor have been proposed to be impact melt, mass wasting deposits or cryolava flows (e.g. Buczkowski et al., 2017; Jaumann et al., 2017; Nathues et al., 2017; Schenk et al., 2017). Each possibility has the potential to provide fascinating insights into Ceres' evolution, including the potential for liquids within Ceres' interior today. The team's in-depth investigation of Occator crater will be presented in an upcoming special issue of the journal Icarus. This special

  4. Strontium isotopic and trace element geochemistry of the saddle mountains and Grande Ronde Basalts of the Columbia River Basalt Group

    International Nuclear Information System (INIS)

    Nelson, D.O.

    1980-01-01

    The Columbia River Basalt (CRB) group displays significant variations in major and trace element and Sr isotopic compositions. These compositions reflect complex and variable origins for the CRB magmas. Among the most varied is the Saddle Mountains Basalt (SMB) in which Sr ratios vary from 0.7078 to 0.7147 +- 0.002. The higher ratios reflect contamination through consistent correlations with major element compositions. Modeling suggests contamination by assimilation of 4.4 to 9.4 wt % of radiogenic crustal rocks. High delta 18 O values (up to +7.68 per mil) support the model. Age and field relations suggest that the contamination flowrocks are not the result of progressive contamination of a single magma, but rather reflect the contamination of independent magmas during this ascent

  5. Prokaryotic diversity, distribution, and insights into their role in biogeochemical cycling in marine basalts and gabbros

    Science.gov (United States)

    Mason, O. U.; di Meo-Savoie, C. A.; Nakagawa, T.; van Nostrand, J. D.; Rosner, M.; Maruyama, A.; Zhou, J.; Fisk, M. R.; Giovannoni, S. J.

    2008-12-01

    Oceanic crust covers nearly 70% of the Earth's surface, of which, the upper, sediment layer is estimated to harbor substantial microbial biomass. Marine crust, however, extends several kilometers beyond this surficial layer, and includes the basalt and gabbro layers. The microbial diversity in basalts is well characterized, yet metabolic diversity is unknown. To date, the microflora associated with gabbros, including microbial and metabolic diversity has not been reported. In our analyses basaltic and gabbroic endoliths were analyzed using terminal restriction fragment length polymorphism, cloning and sequencing, and microarray analysis of functional genes. Our results suggest that despite nearly identical chemical compositions of basalt and gabbro the associated microflora did not overlap. Basalt samples harbor a surprising diversity of seemingly cosmopolitan microorganisms, some of which appear to be basalt specialists. Conversely, gabbros have a low diversity of endoliths, none of which appear to be specifically adapted to the gabbroic environment. Microarray analysis (GeoChip) was used to assay for functional gene diversity in basalts and gabbros. In basalt genes coding for previously unreported processes such as carbon fixation, methane-oxidation, methanogenesis, and nitrogen fixation were present, suggesting that basalts harbor previously unrecognized metabolic diversity. Similar processes were observed in gabbroic samples, yet metabolic inference from phylogenetic relationships of gabbroic endoliths with other microorganisms, suggests that hydrocarbon oxidation is the prevailing metabolism in this environment. Our analyses revealed that the basalt and gabbro layers harbor microorganisms with the genetic potential to significantly impact biogeochemical cycling in the lithosphere and overlying hydrosphere.

  6. Assessing Eruption Column Height in Ancient Flood Basalt Eruptions

    Science.gov (United States)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2015-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at approximately 45 deg N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the approximately 180 km of known Roza fissure length could have supported approximately 36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (approximately 66 Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained

  7. Usability of small impact craters on small surface areas in crater count dating: Analysing examples from the Harmakhis Vallis outflow channel, Mars

    Science.gov (United States)

    Kukkonen, S.; Kostama, V.-P.

    2018-05-01

    The availability of very high-resolution images has made it possible to extend crater size-frequency distribution studies to small, deca/hectometer-scale craters. This has enabled the dating of small and young surface units, as well as recent, short-time and small-scale geologic processes that have occurred on the units. Usually, however, the higher the spatial resolution of space images is, the smaller area is covered by the images. Thus the use of single, very high-resolution images in crater count age determination may be debatable if the images do not cover the studied region entirely. Here we compare the crater count results for the floor of the Harmakhis Vallis outflow channel obtained from the images of the ConTeXt camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO). The CTX images enable crater counts for entire units on the Harmakhis Vallis main valley, whereas the coverage of the higher-resolution HiRISE images is limited and thus the images can only be used to date small parts of the units. Our case study shows that the crater count data based on small impact craters and small surface areas mainly correspond with the crater count data based on larger craters and more extensive counting areas on the same unit. If differences between the results were founded, they could usually be explained by the regional geology. Usually, these differences appeared when at least one cratering model age is missing from either of the crater datasets. On the other hand, we found only a few cases in which the cratering model ages were completely different. We conclude that the crater counts using small impact craters on small counting areas provide useful information about the geological processes which have modified the surface. However, it is important to remember that all the crater counts results obtained from a specific counting area always primarily represent the results from the counting area-not the whole

  8. Surveying Clay Mineral Diversity in the Murray Formation, Gale Crater, Mars

    Science.gov (United States)

    Bristow, T.F.; Blake, D. F..; Vaniman, D. T.; Chipera, S. J.; Rampe, E. B.; Grotzinger, J. P.; McAdam, A. C.; Ming, D. W..; Morrison, S. M.; Yen, A. S.; hide

    2017-01-01

    conditions. In terrestrial settings where alteration sequences of basaltic rocks or sediments are observed, first-stage alteration clay minerals are typically trioctahedral smectite species, as reported from YKB. In later alteration stages trioctahedral clay minerals are replaced by dioctahedral clays as a result of removal and/or oxidation of Fe2+ and Mg. Observed changes in clay mineralogy between YKB and Murray Buttes samples correspond with differences in bulk mineralogy, including: 1) a transition from magnetite to hematite as the main Fe-oxide, 2) increasing abundances of Ca-sulfates and 3) a reduction in the quantity of reactive mafic minerals. This mineralogical change indicates an increasing degree of aqueous alteration and oxidation of mafic detritus in the upper part of the Murray Formation. These results broaden the spectrum of mineralogical facies documented by MSL. Together sedimentology and mineralogy indicate a long-lasting, dynamic fluvial-lacustrine system encompassing a range aqueous geochemical processes under varying redox conditions. Future work is needed to unravel the influence of global and local controls on the range of ancient conditions observed at Gale Crater.

  9. Wildfires Caused by Formation of Small Impact Craters: A Kaali Crater Case

    Science.gov (United States)

    Losiak, Anna; Belcher, Claire; Hudspith, Victoria; Zhu, Menghua; Bronikowska, Malgorzata; Jõeleht, Argo; Plado, Juri

    2016-04-01

    Formation of ~200-km Chicxulub 65 Ma ago was associated with release of significant amount of thermal energy [1,2,3] which was sufficient to start wildfires that had either regional [4] or global [5] range. The evidence for wildfires caused by impacts smaller than Chicxulub is inconclusive. On one hand, no signs of fires are associated with the formation of 24-km Ries crater [6]. On the other hand, the Tunguska site was burned after the impact and the numerical models of the bolide-produced thermal radiation suggest that the Tunguska-like event would produce a thermal flux to the surface that is sufficient to ignite pine needles [7]. However, in case of Tunguska the only proof for the bolide starting the fire comes from an eyewitness description collected many years after the event. Some authors [8] suggest that this fire might have been caused "normaly" later during the same year, induced on dead trees killed by the Tunguska fall. More recently it was observed that the Chelyabinsk meteor [9] - smaller than Tunguska event - did not produced a fire. In order to explore this apparent relationship in more detail, we have studied the proximal ejecta from a 100-m in diameter, ~3500 years old [10] Kaali crater (Estonia) within which we find pieces of charred organic material. Those pieces appear to have been produced during the impact, according to their stratigraphic location and following 14C analysis [19] as opposed to pre- or post-impact forest fires. In order to determine the most probable formation mechanism of the charred organic material found within Kaali proximal ejecta blanket, we: 1) Analyzed charcoal under SEM to identify the charred plants and determine properties of the charcoal related to the temperature of its formation [11]. Detected homogenization of cell walls suggests that at least some pieces of charcoal were formed at >300 °C [11]. 2) Analyzed the reflectance properties of the charred particles in order to determine the intensity with which

  10. Determination of lunar surface ages from crater frequency–size ...

    Indian Academy of Sciences (India)

    and the images from Apollo missions have been calibrated from the lunar soil samples from Apollo and Luna landing sites (Head 1976; Neukum et al. 1975). ... Table 1 shows the ages as derived for the craters with errors. Mare Humorum is believed to be made up of six ring structures of 210, 340, 425, 570 and 1195km.

  11. Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

    NARCIS (Netherlands)

    Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Miller, K. E.; Eigenbrode, J. L.; Summons, R. E.; Brunner, A. E.; Buch, A.; Szopa, C.; Archer, P. D.; Franz, H. B.; Atreya, S. K.; Brinckerhoff, W. B.; Cabane, M.; Coll, P.; Conrad, P. G.; Des Marais, D. J.; Dworkin, J. P.; Fairén, A. G.; François, P.; Grotzinger, J. P.; Kashyap, S.; ten Kate, I. L.; Leshin, L. A.; Malespin, C. A.; Martin, M. G.; Martin-Torres, F. J.; Mcadam, A. C.; Ming, D. W.; Navarro-González, R.; Pavlov, A. A.; Prats, B. D.; Squyres, S. W.; Steele, A.; Stern, J. C.; Sumner, D. Y.; Sutter, B.; Zorzano, M. P.

    The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater.

  12. Role of impact cratering for Mars sample return

    International Nuclear Information System (INIS)

    Schultz, P.H.

    1988-01-01

    The preserved cratering record of Mars indicates that impacts play an important role in deciphering Martian geologic history, whether as a mechanism to modify the lithosphere and atmosphere or as a tool to sample the planet. The various roles of impact cratering in adding a broader understanding of Mars through returned samples are examined. Five broad roles include impact craters as: (1) a process in response to a different planetary localizer environment; (2) a probe for excavating crustal/mantle materials; (3) a possible localizer of magmatic and hydrothermal processes; (4) a chronicle of changes in the volcanic, sedimentary, atmospheric, and cosmic flux history; and (5) a chronometer for extending the geologic time scale to unsampled regions. The evidence for Earth-like processes and very nonlunar styles of volcanism and tectonism may shift the emphasis of a sampling strategy away from equally fundamental issues including crustal composition, unit ages, and climate history. Impact cratering not only played an important active role in the early Martian geologic history, it also provides an important tool for addressing such issues

  13. Wet Weather Crater Repair Technologies for Grooved and Smooth Pavements

    Science.gov (United States)

    2018-04-30

    Dean Geotechnical and Structures Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199...ORGANIZATION REPORT NUMBER U.S. Army Engineer Research and Development Center Geotechnical and Structures Laboratory 3909 Halls Ferry Road ...SUBJECT TERMS Crater Concrete Rain and rainfall ADR Grooved pavement Smooth pavement Runoff Runways (Aeronautics) – Maintenance and repair

  14. Malaria among the pastoral communities of the Ngorongoro Crater ...

    African Journals Online (AJOL)

    Malaria among the pastoral communities of the Ngorongoro Crater Area, northern Tanzania. L.E.G Mboera, R.C Malima, P.E Mangesho, K.P Senkoro, V Mwingira. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  15. Crater formation by single ions, cluster ions and ion "showers"

    CERN Document Server

    Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

    2011-01-01

    The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...

  16. UTILIZATION OF BASALT FIBERS AS A RAW MATERIAL FOR CLAY CERAMIC PRODUCTION

    Directory of Open Access Journals (Sweden)

    Supawan Vichaphund

    2016-03-01

    Full Text Available This research aimed to investigate the possibility of utilization basalt fibers as a raw material for ceramic production. Both quartz and feldspar were replaced partially or entirely by basalt fiber in the range of 10-25 wt%. The mixture of ceramic powders and basalt fibers were uniaxially pressed and sintered at temperatures between 1000 and 1200°C for 1 h. The substitution of basalt fibers in ceramic compositions demonstrated the positive effect on the physical and mechanical properties. The addition of basalt fibers in an appropriate amount enhance the densification and reduce sintering temperature of clay-based ceramics (CB-0 from 1200 to 1150°C. The highest density and strength were 2.40 g/cm³ and 116 MPa, respectively, when replacing feldspar and quartz with basalt up to 20 wt% (CB-20 and sintering at 1150°C.

  17. Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon

    Science.gov (United States)

    Bacon, Charles R.

    2008-01-01

    Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive

  18. Long-Term Recovery of Life in the Chicxulub Crater

    Science.gov (United States)

    Lowery, C.; Jones, H.; Bralower, T. J.; Smit, J.; Rodriguez-Tovar, F. J.; Whalen, M. T.; Owens, J. D.; Expedition 364 Science Party, I. I.

    2017-12-01

    The Chicxulub Crater on the Yucatán Peninsula of Mexico was formed by the impact of an asteroid 66 Ma that caused the extinction of 75% of genera on Earth. Immediately following the impact, the decimated ecosystem began the long process of recovery, both in terms of primary productivity and species diversity. This well-documented process was heterogeneous across the world ocean, but until the present time it has been inaccessible at ground zero of the impact. IODP/ICDP Exp. 364 recovered 9.5 m of pelagic limestone spanning the entire Paleocene, including a continuous section spanning the first 5 myr following the impact. The Chicxulub Crater is the largest known marine impact crater on Earth, and the recovery of the ecosystem presented here is the first such record of long-term primary succession in the sterile zone of a large impact crater. Planktic and benthic foraminifera, calcareous nannoplankton, calcispheres, bioturbation, and geochemical proxies all indicate that export productivity in the Chicxulub Crater recovered rapidly (within 30 kyr) following the impact. Recovery in terms of diversity and species abundance took much longer, and varied between groups. Planktic foraminifera quickly diversified, with all common Paleocene tropical/subtropical species appearing roughly when expected. Trace fossils appear rapidly after the event, with a progressive recovery through the lowermost Paleocene. Calcareous nannoplankton took much longer to recover, and disaster taxa like Braarudosphaera dominated the assemblage well into the late Paleocene. Paleoecology and geochemistry relate these trends to oceanographic conditions within the Chicxulub Crater. Planktic foraminifera from known depth habitats, including Morozovellids, Acarininids, Chiloguembelinids, and Subbotinids, track changes in the water column structure and paleoredox conditions within the crater. Diverse and abundant macro- and microbenthic organisms indicate food availability and good oxygen conditions

  19. Methods of simulating low redox potential (Eh) for a basalt repository

    International Nuclear Information System (INIS)

    Jantzen, C.M.

    1983-01-01

    Basalt groundwaters have inherently low redox potentials, approximately -0.4V, which can be measured with platinum electrodes, but are difficult to reproduce during leaching experiments. In the presence of deionized water, crushed basalt reaches the measured Eh-pH values of a basalt repository. Other waste package components, such as iron, will interact with groundwater in different ways under oxic or anoxic conditions since the presence of any redox active solid will affect the groundwater Eh. 26 references, 4 figures

  20. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    International Nuclear Information System (INIS)

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed

  1. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed.

  2. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian)

    OpenAIRE

    Daniela Ogrean

    2001-01-01

    The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes) indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Tim...

  3. Angrites: A Volatile-rich Variety of Asteroidal Basalt (Except for Alkalis and Gallium!)

    Science.gov (United States)

    Warren, P. H.; Kallemeyn, G. W.

    1995-09-01

    Angrites are commonly viewed as extremely volatile-depleted, and a related notion is that they formed by differentiation of a very CAI-rich material [e.g., 1]. Partial melting experiments reportedly reproduce the bulk compositions (although not fassaite-rich mineralogy) of angrites with Allende as starting material [2], but highly CAI-rich parent materials are difficult to reconcile with isotopic and REE data [3,4]. Mittlefehldt and Lindstrom [5] inferred from the low Na/Al ratios of angrites that outgassing, and thus primordial magmatism, was more intense on their parent body than on the eucrite parent asteroid. Of seven elements that (a) have been adequately determined in angrites, and (b) are far more volatile (solar-nebula 50% condensation T [6] = 690-430 K) than the alkalis (1000-910 K), four are enriched, and none is significantly depleted, in average angrite compared to average eucrite or low-Ti mare basalt (Figure). Gallium, which is of intermediate volatility (830 K), is depleted to roughly the same extent as Na and K. Results for A881371 [3] are incomplete (Zn, 6 micrograms/g, is near INAA detection limit), but even based only on AdoR and the two LEW angrites, this pattern seems firmly established. Apparent gas cavities in A881371 [7] also suggest that volatiles are far from uniformly depleted. The only elements known to be depleted, as volatiles, by clearly significant factors in angrites versus eucrites or lunar basalts, are alkalis plus gallium. Besides being moderately volatile, a noteworthy characteristic shared among Ga and alkalis (and not shared with elements such as Br, Se, and Zn) is that these elements probably tend to partition into crustal feldspar during gross differentiation of small (low-pressure) bodies. If gallium + alkalis were depleted by a single process starting from "normal" chondritic material, that process would seem to require selective exposure of a feldspar-enriched region (i.e., crust) to extremely high temperature. Igneous

  4. Rb-Sr and Sm-Nd chronology and genealogy of mare basalts from the Sea of Tranquility

    Science.gov (United States)

    Papanastassiou, D. A.; Depaolo, D. J.; Wasserburg, G. J.

    1977-01-01

    Rb-Sr and Sm-Nd ages of two Apollo 11 mare basalts, high-K basalt 10072 and low-K basalt 10062, are reported. Rb-Sr, Sm-Nd, and Ar-40-Ar-39 ages are in good agreement and indicate an extensive time interval for filling of the Sea of Tranquility, presumably by thin lava flows, in agreement with similar observations for the Ocean of Storms. Initial Sr and Nd isotopic compositions on Apollo 11 basalts reveal at least two parent sources producing basalts. The Sm-Nd isotopic data demonstrate that low-K and high-Ti basalts from Apollo 11 and 17 derived from distinct reservoirs, while low-Ti Apollo 15 mare basalt sources have Sm/Nd similar to the sources of Apollo 11 basalts. Groupings of mare basalt based on Ti content and on isotopic data do not coincide.

  5. A Brillouin scattering study of hydrous basaltic glasses: the effect of H2O on their elastic behavior and implications for the densities of basaltic melts

    Science.gov (United States)

    Wu, Lei; Yang, De-Bin; Liu, Jun-Xiu; Hu, Bo; Xie, Hong-Sen; Li, Fang-Fei; Yu, Yang; Xu, Wen-Liang; Gao, Chun-Xiao

    2017-06-01

    Hydrous basalt glasses with water contents of 0-6.82% were synthesized using a multi-anvil press at 1.0-2.0 GPa and 1200-1400 °C. The starting materials were natural Mesozoic basalts from the eastern North China Craton (NCC). Their sound velocities and elastic properties were measured by Brillouin scattering spectroscopy. The longitudinal ( V P) and shear ( V S) wave velocities decreased with increasing water content. Increasing the synthesis pressure resulted in the glass becoming denser, and finally led to an increase in V P. As the degree of depolymerization increased, the V P, V S, and shear and bulk moduli of the hydrous basalt glasses decreased, whereas the adiabatic compressibility increased. The partial molar volumes of water (ν) under ambient conditions were independent of composition, having values of 11.6 ± 0.8, 10.9 ± 0.6 and 11.5 ± 0.5 cm3/mol for the FX (Feixian), FW (Fuxin), and SHT (Sihetun) basalt glasses, respectively. However, the {{V}_{{{{H}}_{{2}}}{O}}} values measured at elevated temperatures and pressures are increasing with increasing temperature or decreasing pressure. The contrasting densities of these hydrous basalt melts with those previously reported for mid-ocean ridge basalt and preliminary reference Earth model data indicate that hydrous basalt melts may not maintain gravitational stability at the base of the upper mantle.

  6. Crater Morphometry and Crater Degradation on Mercury: Mercury Laser Altimeter (MLA) Measurements and Comparison to Stereo-DTM Derived Results

    Science.gov (United States)

    Leight, C.; Fassett, C. I.; Crowley, M. C.; Dyar, M. D.

    2017-01-01

    Two types of measurements of Mercury's surface topography were obtained by the MESSENGER (MErcury Surface Space ENvironment, GEochemisty and Ranging) spacecraft: laser ranging data from Mercury Laser Altimeter (MLA) [1], and stereo imagery from the Mercury Dual Imaging System (MDIS) camera [e.g., 2, 3]. MLA data provide precise and accurate elevation meaurements, but with sparse spatial sampling except at the highest northern latitudes. Digital terrain models (DTMs) from MDIS have superior resolution but with less vertical accuracy, limited approximately to the pixel resolution of the original images (in the case of [3], 15-75 m). Last year [4], we reported topographic measurements of craters in the D=2.5 to 5 km diameter range from stereo images and suggested that craters on Mercury degrade more quickly than on the Moon (by a factor of up to approximately 10×). However, we listed several alternative explanations for this finding, including the hypothesis that the lower depth/diameter ratios we observe might be a result of the resolution and accuracy of the stereo DTMs. Thus, additional measurements were undertaken using MLA data to examine the morphometry of craters in this diameter range and assess whether the faster crater degradation rates proposed to occur on Mercury is robust.

  7. Geology of the Sabie River Basalt Formation in the Southern Kruger National Park

    Directory of Open Access Journals (Sweden)

    R.J. Sweeney

    1986-11-01

    Full Text Available The Sabie River Basalt Formation (SRBF in the central Lebombo is a virtually continuous sequence of basaltic lavas some 2 500 m thick that was erupted 200 - 179 Ma ago. Flows are dominantly pahoehoe in character and vary from 2 m to 20 m in thickness. Dolerite dykes cross-cutting the basalt sequence probably represent feeders to this considerable volcanic event. Volcanological features observed within the SRBF are described. Two chemically distinct basaltic magma types are recognised, the simultaneous eruption of which presents an intriguing geochemical problem as to their origins.

  8. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr [University of Tartu, Institute of Physics (Estonia); Biland, Alex [HHK Technologies, Houston (United States); Tkaczyk, Alan Henry, E-mail: alan@ut.ee [University of Tartu, Institute of Physics (Estonia)

    2015-04-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications.

  9. Basalt fiber manufacturing technology and the possibility of its use in dentistry

    International Nuclear Information System (INIS)

    Karavaeva, E; Rogozhnikov, A; Nikitin, V; Cherepennikov, Yu; Lysakov, A

    2015-01-01

    The article touches upon the technology of basalt fiber manufacturing and prospects of its use in dental practice. Two kinds of construction using basalt fiber have been proposed. The first one is a splinting construction for mobile teeth and the second one is the reinforced base for removable plate-denture. The work presents the results of the investigation of physical and mechanical properties of the constructions based on basalt fiber. It also describes the aspects of biomechanical modeling of such constructions in the ANSYS software package. The results of the investigation have proved that applying constructions using basalt fiber is highly promising for prosthetic dentistry practice. (paper)

  10. Basalt Fiber for Volcanic Slag Lightweight Aggregate Concrete Research on the Impact of Performance

    Science.gov (United States)

    Xiao, Li-guang; Li, Gen-zhuang

    2018-03-01

    In order to study the effect of basalt fiber on the mechanical properties and durability of volcanic slag lightweight aggregate concrete, the experimental study on the flexural strength, compressive strength and freeze-thaw resistance of volcanic slag concrete with different basalt fiber content were carried out, the basalt fiber was surface treated with NaOH and water glass, the results show that the surface treatment of basalt fiber can significantly improve the mechanical properties, durability and other properties of volcanic slag lightweight aggregate concrete.

  11. Basalt fiber manufacturing technology and the possibility of its use in dentistry

    Science.gov (United States)

    Karavaeva, E.; Rogozhnikov, A.; Nikitin, V.; Cherepennikov, Yu; Lysakov, A.

    2015-11-01

    The article touches upon the technology of basalt fiber manufacturing and prospects of its use in dental practice. Two kinds of construction using basalt fiber have been proposed. The first one is a splinting construction for mobile teeth and the second one is the reinforced base for removable plate-denture. The work presents the results of the investigation of physical and mechanical properties of the constructions based on basalt fiber. It also describes the aspects of biomechanical modeling of such constructions in the ANSYS software package. The results of the investigation have proved that applying constructions using basalt fiber is highly promising for prosthetic dentistry practice.

  12. Radiation shielding properties of a novel cement–basalt mixture for nuclear energy applications

    International Nuclear Information System (INIS)

    Ipbüker, Cagatay; Nulk, Helena; Gulik, Volodymyr; Biland, Alex; Tkaczyk, Alan Henry

    2015-01-01

    Highlights: • Basalt fiber is a relatively cheap material that can be used as reinforcement. • Gamma-ray attenuation remains relatively stable with addition of basalt fiber. • Neutron attenuation remains relatively stable with addition of basalt fiber. • Cement–basalt mixture has a good potential for use in nuclear energy applications. - Abstract: The radiation shielding properties of a new proposed building material, a novel cement–basalt fiber mixture (CBM), are investigated. The authors analyze the possibility of this material to be a viable substitute to outgoing materials in nuclear energy applications, which will lead to a further sustained development of nuclear energy in the future. This computational study involves four types of concrete with various amounts of basalt fiber in them. The gamma-ray shielding characteristics of proposed CBM material are investigated with the help of WinXCom program, whereas the neutron shielding characteristics are computed by the Serpent code. For gamma-ray shielding, we find that the attenuation coefficients of concretes with basalt fibers are not notably influenced by the addition of fibers. For neutron shielding, additional basalt fiber in mixture presents negligible effect on neutron radiation shielding. With respect to radiation shielding, it can be concluded that basalt fibers have good potential as an addition to heavyweight concrete for nuclear energy applications

  13. Mineral Fractionation during Sediment Comminution and Transport in Fluvio-Deltaic and Lacustrine Rocks of the Bradbury Group, Gale Crater, Mars

    Science.gov (United States)

    Siebach, K. L.; Baker, M. B.; Grotzinger, J. P.; McLennan, S. M.; Gellert, R.; Thompson, L. M.; Hurowitz, J.

    2017-12-01

    Mineral distribution patterns in sediments of the Bradbury group in Gale crater, interpreted from observations by the Mars Science Laboratory rover Curiosity, show the importance of transport mechanics in source-to-sink processes on Mars. The Bradbury group is comprised of basalt-derived mudstones to conglomerates exposed along the modern floor of Gale crater and analyzed along a 9-km traverse of the Curiosity rover. Over 110 bulk chemistry analyses of the rocks were acquired, along with two XRD mineralogical analyses of the mudstone. These rocks are uniquely suited for analysis of source-to-sink processes because they exhibit a wide range of compositions, but (based on multiple chemical weathering proxies) they appear to have experienced negligible cation-loss during weathering and erosion. Chemical variations between analyses correlate with sediment grain sizes, with coarser-grained rocks enriched in plagioclase components SiO2, Al2O3, and Na2O, and finer-grained rocks enriched in components of mafic minerals, consistent with grain-size sorting of mineral fractions during sediment transport. Further geochemical and mineralogical modeling supports the importance of mineral fractionation: even though the limited XRD data suggests that some fraction (if not all) of the rocks contain clays and an amorphous component, models show that 90% of the compositions measured are consistent with sorting of primary igneous minerals from a plagioclase-phyric subalkaline basalt (i.e., no corrections for cation-loss are required). The distribution of K2O, modeled as a potassium feldspar component, is an exception to the major-element trends because it does not correlate with grain size, but has an elevation-dependent signal likely correlated with the introduction of a second source material. However, the dominant compositional trends within the Bradbury group sedimentary rocks are correlated with grain size and consistent with mineral fractionation of minimally

  14. Nuclear waste repository in basalt: preconceptual design guidelines

    International Nuclear Information System (INIS)

    1979-06-01

    The development of the basalt waste isolation program parallels the growing need for permanent, environmentally safe, and secure means to store nuclear wastes. The repository will be located within the Columbia Plateau basalt formations where these ends can be met and radiological waste can be stored. These wastes will be stored such that the wastes may be retrieved from storage for a period after placement. After the retrieval period, the storage locations will be prepared for terminal storage. The terminal storage requirements will include decommissioning provisions. The facility boundaries will encompass no more than several square miles of land which will be above a subsurface area where the geologic makeup is primarily deep basaltic rock. The repository will receive, from an encapsulation site(s), nuclear waste in the form of canisters (not more than 18.5 feet x 16 inches in diameter) and containers (55-gallon drums). Canisters will contain spent fuel (after an interim 5-year storage period), solidified high-level wastes (HLW), or intermediate-level wastes (ILW). The containers (drums) will package the low-level transuranic wastes (LL-TRU). The storage capacity of the repository will be expanded in a time-phased program which will require that subsurface development (repository expansion) be conducted concurrently with waste storage operations. The repository will be designed to store the nuclear waste generated within the predictable future and to allow for reasonable expansion. The development and assurance of safe waste isolation is of paramount importance. All activities will be dedicated to the protection of public health and the environment. The repository will be licensed by the US Nuclear Regulatory Commission (NRC). Extensive efforts will be made to assure selection of a suitable site which will provide adequate isolation

  15. Nuclear waste repository in basalt: preconceptual design guidelines

    Energy Technology Data Exchange (ETDEWEB)

    1979-06-01

    The development of the basalt waste isolation program parallels the growing need for permanent, environmentally safe, and secure means to store nuclear wastes. The repository will be located within the Columbia Plateau basalt formations where these ends can be met and radiological waste can be stored. These wastes will be stored such that the wastes may be retrieved from storage for a period after placement. After the retrieval period, the storage locations will be prepared for terminal storage. The terminal storage requirements will include decommissioning provisions. The facility boundaries will encompass no more than several square miles of land which will be above a subsurface area where the geologic makeup is primarily deep basaltic rock. The repository will receive, from an encapsulation site(s), nuclear waste in the form of canisters (not more than 18.5 feet x 16 inches in diameter) and containers (55-gallon drums). Canisters will contain spent fuel (after an interim 5-year storage period), solidified high-level wastes (HLW), or intermediate-level wastes (ILW). The containers (drums) will package the low-level transuranic wastes (LL-TRU). The storage capacity of the repository will be expanded in a time-phased program which will require that subsurface development (repository expansion) be conducted concurrently with waste storage operations. The repository will be designed to store the nuclear waste generated within the predictable future and to allow for reasonable expansion. The development and assurance of safe waste isolation is of paramount importance. All activities will be dedicated to the protection of public health and the environment. The repository will be licensed by the US Nuclear Regulatory Commission (NRC). Extensive efforts will be made to assure selection of a suitable site which will provide adequate isolation.

  16. Characterization of the Morphometry of Impact Craters Hosting Polar Deposits in Mercury's North Polar Region

    Science.gov (United States)

    Talpe Matthieu; Zuber, Maria T.; Yang, Di; Neumann, Gregory A.; Solomon, Sean C.; Mazarico, Erwan; Vilas, Faith

    2012-01-01

    Earth-based radar images of Mercury show radar-bright material inside impact craters near the planet s poles. A previous study indicated that the polar-deposit-hosting craters (PDCs) at Mercury s north pole are shallower than craters that lack such deposits. We use data acquired by the Mercury Laser Altimeter on the MESSENGER spacecraft during 11 months of orbital observations to revisit the depths of craters at high northern latitudes on Mercury. We measured the depth and diameter of 537 craters located poleward of 45 N, evaluated the slopes of the northern and southern walls of 30 PDCs, and assessed the floor roughness of 94 craters, including nine PDCs. We find that the PDCs appear to have a fresher crater morphology than the non-PDCs and that the radar-bright material has no detectable influence on crater depths, wall slopes, or floor roughness. The statistical similarity of crater depth-diameter relations for the PDC and non-PDC populations places an upper limit on the thickness of the radar-bright material (< 170 m for a crater 11 km in diameter) that can be refined by future detailed analysis. Results of the current study are consistent with the view that the radar-bright material constitutes a relatively thin layer emplaced preferentially in comparatively young craters.

  17. Basalt features observed in outcrops, cores, borehole video imagery and geophysical logs, and basalt hydrogeologic study at the Idaho National Engineering Laboratory, Eastern Idaho

    International Nuclear Information System (INIS)

    Bennecke, W.M.

    1996-10-01

    A study was undertaken to examine permeable zones identified in boreholes open to the underlying basalt and to describe the vertical cross flows present in the boreholes. To understand the permeable zones in the boreholes detailed descriptions and measurements of three outcrops in the Snake River Plain, three cores at the Idaho Chemical Processing Plant (ICPP) at the INEL, and over fifty borehole TV logs from the INEL were carried out. Based on the observations made on the three outcrops an idealized basalt lava flow model was generated that used a set of nomenclature that would be standard for the basalt lava flows studied. An upper vesicular zone, a sometimes absent columnar zone, central zone, and lower vesicular zone make up the basalt lava flow model. The overall distinction between the different zones are based on the vesicle shape size, vesicularity, and fractures present. The results of the studies also indicated that the basalt lava flows at the INEL are distal to medial facies pahoehoe lava flows with close fitting contacts. The most permeable zones identified in these basalts are fractured vesiculated portions of the top of the lava flow, the columnar areas, and basalt-flow contacts in order of importance. This was determined from impeller flowmeter logging at the INEL. Having this information a detailed stratigraphy of individual basalt lava flows and the corresponding permeable units were generated. From this it was concluded that groundwater flow at the ICPP prefers to travel along thin basalt lava flows or flow-units. Flow direction and velocity of intrawell flows detected by flowmeter is controlled by a nearby pumping well

  18. Sentinel Gap basalt reacted in a temperature gradient

    International Nuclear Information System (INIS)

    Charles, R.W.; Bayhurst, G.K.

    1983-01-01

    Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms were centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure was 1/3 kbar. All prisms showed large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration reacted readily to clays at all temperatures. The first four prisms were coated with a calcium smectite, and the last two prisms were covered with discrete patches of potassium-rich phengite and alkali feldspar. The results indicated that clays may act as adsorbers of various ions

  19. Sentinel Gap basalt reacted in a temperature gradient

    International Nuclear Information System (INIS)

    Charles, R.W.; Bayhurst, G.K.

    1982-01-01

    Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms are centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure is 1/3 kbar. All prisms show large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration readily reacts to clays at all temperatures. The first four prisms are coated with a Ca-smectite while the last two prisms are covered with discrete patches of K rich phengite and alkali feldspar. The clays may act as adsorbers of various ions

  20. Environmental issue identification for the Basalt Waste Isolation Project

    International Nuclear Information System (INIS)

    Carrell, D.J.; Jones, K.A.

    1980-04-01

    A preliminary evaluation of environmental issues is provided in this report. It contains summary of the thought process that was used during the area characterization studies for a geological repository for high-level radioactive wastes. Environmental issues are discussed separately for construction, operation, and long term isolation aspects of a repository in basalt. During construction the primary environmental concerns are public perception and water resources; intermediate concerns are air quality, ecosystems, physical resources, and cultural and social resources. During operation, the primary environmental issues concern the transport of radioactive materials and physical resources. Long term environmental issues envolve water resources and borehole plugging

  1. Basalt Waste Isolation Project exploratory shaft site: Final reclamation report

    International Nuclear Information System (INIS)

    Brandt, C.A.; Rickard, W.H. Jr.

    1990-06-01

    The restoration of areas disturbed by activities of the Basalt Waste Isolation Project (BWIP) constitutes a unique operation at the US Department of Energy's (DOE) Hanford Site, both from the standpoint of restoration objectives and the time frame for accomplishing these objectives. The BWIP reclamation program comprises three separate projects: borehole reclamation, Near Surface Test Facility (NSTF) reclamation, and Exploratory Shaft Facility (ESF) reclamation. The main focus of this report is on determining the success of the revegetation effort 1 year after work was completed. This report also provides a brief overview of the ESF reclamation program. 21 refs., 7 figs., 14 tabs

  2. Penetration of molten core materials into basaltic and limestone concrete

    International Nuclear Information System (INIS)

    Sutherland, H.J.

    1978-01-01

    In conjunction with the small-scale, melt-concrete interaction tests being conducted at Sandia Laboratories, an acoustic technique has been used to monitor the penetration of molten core materials into basaltic and limestone concrete. Real time plots of the position of the melt/concrete interface have been obtained, and they illustrate that the initial penetration rate of the melt may be of the order of 80 mm/min. Phenomena deduced by the technique include a non-wetted melt/concrete interface

  3. Hydrologic bibliography of the Columbia River basalts in Washington

    International Nuclear Information System (INIS)

    Tanaka, H.H.; Wildrick, L.

    1978-07-01

    This bibliography is part of the hydrologic data compilation effort of the Columbia Plateau Hydrology Study, Rockwell Hanford Operations' Waste Isolation Program. It includes references on both surface and subsurface hydrology directly or indirectly related to the Washington State portion of the Columbia River basalts. A comprehensive, annotated bibliography of the Pasco Basin (including the Hanford site) hydrology has been prepared for Rockwell Hanford Operations under the Pasco Basin Hydrology Study. In order to avoid unnecessary duplication, no effort was made to include a complete list of bibliographic references on Hanford in this volume

  4. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Mengal Ali Nawaz

    2014-07-01

    Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

  5. Melt density and the average composition of basalt

    Science.gov (United States)

    Stolper, E.; Walker, D.

    1980-01-01

    Densities of residual liquids produced by low pressure fractionation of olivine-rich melts pass through a minimum when pyroxene and plagioclase joint the crystallization sequence. The observation that erupted basalt compositions cluster around the degree of fractionation from picritic liquids corresponding to the density minimum in the liquid line of descent may thus suggest that the earth's crust imposes a density fiber on the liquids that pass through it, favoring the eruption of the light liquids at the density minimum over the eruption of denser more fractionated and less fractionated liquids.

  6. Potential for observing and discriminating impact craters and comparable volcanic landforms on Magellan radar images

    International Nuclear Information System (INIS)

    Ford, J.P.

    1989-01-01

    Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry

  7. Experimental assessment of borehole wall drilling damage in basaltic rocks

    International Nuclear Information System (INIS)

    Fuenkajorn, K.; Daemen, J.J.K.

    1986-06-01

    Ring tension tests, permeability tests, and microscopic fracture studies have been performed to investigate the borehole damage induced at low confining pressure by three drilling techniques (diamond, percussion and rotary). Specimens are drilled with three hole sizes (38, 76, and 102 mm diameter) in Pomona basalt and Grande basaltic andesite. The damaged zone is characterized in terms of fractures and fracture patterns around the hole, and in terms of tensile strength reduction of the rock around the holes. Experimental results show that the thickness of the damaged zone around the hole ranges from 0.0 to 1.7 mm. A larger drill bit induces more wall damage than does a smaller one. Different drilling techniques show different damage characteristics (intensity and distribution). Damage characteristics are governed not only by drilling parameters (bit size, weight on bit, rotational speed, diamond radius, and energy), but also by properties of the rock. The weaker rock tends to show more intense damage than does the stronger one. Cracks within grains or cleavage fractures are predominant in slightly coarser grained rock (larger than 0.5 mm grain size) while intergranular cracks are predominant in very fine grained rock (smaller than 0.01 mm grain size). The damaged zones play no significant role in the flow path around a borehole plug

  8. The Disruption of Tephra Fall Deposits by Basaltic Lava Flows

    Science.gov (United States)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2010-12-01

    Complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents of the Roza Member in the Columbia River Basalt Province, (CRBP), USA, illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter tephra fall deposits. Thin pahoehoe lobes and sheet lobes occur intercalated with tephra deposits and provide evidence for synchronous effusive and explosive activity. Tephra that accumulated on the tops of inflating pahoehoe flows became disrupted by tumuli, which dissected the overlying sheet into a series of mounds. During inflation of subjacent tumuli tephra percolated down into the clefts and rubble at the top of the lava, and in some cases came into contact with lava hot enough to thermally alter it. Lava breakouts from the tumuli intruded up through the overlying tephra deposit and fed pahoehoe flows that spread across the surface of the aggrading tephra fall deposit. Non-welded scoria fall deposits were compacted and welded to a depth of ~50 cm underneath thick sheet lobes. These processes, deduced from the field relationships, have resulted in considerable stratigraphic complexity in proximal regions. We also demonstrate that, when the advance of lava and the fallout of tephra are synchronous, the contacts of some tephra sheets can be diachronous across their extent. The net effect is to reduce the usefulness of pyroclastic deposits in reconstructing eruption dynamics.

  9. Network topology of olivine-basalt partial melts

    Science.gov (United States)

    Skemer, Philip; Chaney, Molly M.; Emmerich, Adrienne L.; Miller, Kevin J.; Zhu, Wen-lu

    2017-07-01

    The microstructural relationship between melt and solid grains in partially molten rocks influences many physical properties, including permeability, rheology, electrical conductivity and seismic wave speeds. In this study, the connectivity of melt networks in the olivine-basalt system is explored using a systematic survey of 3-D X-ray microtomographic data. Experimentally synthesized samples with 2 and 5 vol.% melt are analysed as a series of melt tubules intersecting at nodes. Each node is characterized by a coordination number (CN), which is the number of melt tubules that intersect at that location. Statistically representative volumes are described by coordination number distributions (CND). Polyhedral grains can be packed in many configurations yielding different CNDs, however widely accepted theory predicts that systems with small dihedral angles, such as olivine-basalt, should exhibit a predominant CN of four. In this study, melt objects are identified with CN = 2-8, however more than 50 per cent are CN = 4, providing experimental verification of this theoretical prediction. A conceptual model that considers the role of heterogeneity in local grain size and melt fraction is proposed to explain the formation of nodes with CN ≠ 4. Correctly identifying the melt network topology is essential to understanding the relationship between permeability and porosity, and hence the transport properties of partial molten mantle rocks.

  10. Characterization and recognition of intraflow structures, Grande Ronde Basalt

    International Nuclear Information System (INIS)

    Long, P.E.

    1978-09-01

    This investigation was carried out as part of a feasibility study for long-term storage of nuclear waste at depth in the Pasco Basin. Three general types of intraflow structures were found at Sentinel Gap: flows with stubby, irregular columns that lack a well-developed entablature; flows consisting of multiple tiers of largely entablature-type columns; and flows with a well-developed colonnade and entablature showing a sharp break between the two. Certain features occur locally in all three types of intraflow structures: variations in fracture morphology, primary platey fracture zones, pillow-palagonite zones, and tectonically induced zones of closely spaced fractures. Fractures in each of the three types of flows were logged both at the surface and in core from Core Hole DH-5, and petrographic textures of basalt sampled from surface exposures were examined. The textures of the basalt correlate with the intraflow structures and provide a technique for identifying flows as to their general type of intraflow structure, locating internal contacts between intraflow structures and possibly estimating fracture density within flows. Fracture logging, on the other hand, does not accurately delimit intraflow structures

  11. Noble gas and carbon isotopes in Mariana Trough basalt glasses

    International Nuclear Information System (INIS)

    Bernard, M.; Jambon, A.; Gamo, T.; Nishio, Y.; Sano, Y.

    1998-01-01

    Noble gas elemental and isotopic compositions have been measured as well as the abundance of C and its isotopic ratios in 11 glasses from submarine pillow basalts collected from the Mariana Trough. The 3 He/ 4 He ratios of 8.22 and 8.51 R atm of samples dredged from the central Mariana Trough (similar18N) agree well with that of the Mid-Ocean Ridge Basalt (MORB) glasses (8.4±0.3 R atm ), whereas a mean ratio of 8.06±0.35 R atm in samples from the northern Mariana Trough (similar20N) is slightly lower than those of MORB. One sample shows apparent excess of 20 Ne and 21 Ne relative to atmospheric Ne, suggesting incorporation of solar-type Ne in the magma source. There is a positive correlation between 3 He/ 4 He and 40 Ar/ 36 Ar ratios, which may be explained by mixing between MORB-type and atmospheric noble gases. Excess 129 Xe is observed in the sample which also shows 20 Ne and 21 Ne excesses. Observed δ 13 C values of similar20N samples vary from -3.76 per thousand to -2.80 per thousand, and appear higher than those of MORB, and the corresponding CO 2 / 3 He ratios are higher than those of MARA samples at similar18N, suggesting C contribution from the subducted slab. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. Design approaches for access plugs in a basalt repository

    International Nuclear Information System (INIS)

    O'Rourke, J.; Allirot, D.; O'Connor, K.

    1982-01-01

    This paper describes research, laboratory testing, and analytical approaches taken toward the development of designs for sealing boreholes, shafts, and tunnels penetrating from ground surface to a deep, mined nuclear waste repository in basalt. A material selection process leading to identification of preferred sealing materials is discussed, and the laboratory testing program to define the geochemical and geotechnical performance of these materials is described. Analysis of the environmental conditions in the Columbia Plateau basalt flows leads to identification of tentative design criteria for plug systems. These design criteria include performance of the plug as a hydraulic barrier and as a radionuclide barrier. An important problem for effective performance of a plug system as a hydraulic barrier is shown to be a potentially disturbed zone surrounding the excavation in the stressed and jointed host rock. An idealized one-dimensional numerical model is described for analyzing the performance of the plug as a barrier to radionuclide transport. The preliminary analyses led to the conclusion that the composition and dimensions of practical candidate plugs can satisfy both hydraulic and radionuclide barrier criteria. Examples of candidate designs are shown for boreholes, shafts, and tunnels. 9 references, 6 figures, 6 tables

  13. Evaluation of thermobarometry for spinel lherzolite fragments in alkali basalts

    Science.gov (United States)

    Ozawa, Kazuhito; Youbi, Nasrrddine; Boumehdi, Moulay Ahmed; McKenzie, Dan; Nagahara, Hiroko

    2017-04-01

    Geothermobarometry of solid fragments in kimberlite and alkali basalts, generally called "xenoliths", provides information on thermal and chemical structure of lithospheric and asthenospheric mantle, based on which various chemical, thermal, and rheological models of lithosphere have been constructed (e.g., Griffin et al., 2003; McKenzie et al., 2005; Ave Lallemant et al., 1980). Geothermobarometry for spinel-bearing peridotite fragments, which are frequently sampled from Phanerozoic provinces in various tectonic environments (Nixon and Davies, 1987), has essential difficulties, and it is usually believed that appropriated barometers do not exist for them (O'Reilly et al., 1997; Medaris et al., 1999). Ozawa et al. (2016; EGU) proposed a method of geothermobarometry for spinel lherzolite fragments. They applied the method to mantle fragments in alkali basalts from Bou Ibalhatene maars in the Middle Atlas in Morocco (Raffone et al. 2009; El Azzouzi et al., 2010; Witting et al., 2010; El Messbahi et al., 2015). Ozawa et al. (2016) obtained 0.5GPa pressure difference (1.5-2.0GPa) for 100°C variation in temperatures (950-1050°C). However, it is imperative to verify the results on the basis of completely independent data. There are three types of independent information: (1) time scale of solid fragment extraction, which may be provided by kinetics of reactions induced by heating and/or decompression during their entrapment in the host magma and transportation to the Earth's surface (Smith, 1999), (2) depth of the host basalt formation, which may be provided by the petrological and geochemical studies of the host basalts, and (3) lithosphere-asthenosphere boundary depths, which may be estimated by geophysical observations. Among which, (3) is shown to be consistent with the result in Ozawa et al. (2016). We here present that the estimated thermal structure just before the fragment extraction is fully supported by the information of (1) and (2). Spera (1984) reviewed

  14. Are pre-crater mounds gas-inflated?

    Science.gov (United States)

    Leibman, Marina; Kizyakov, Alexandr; Khomutov, Artem; Dvornikov, Yury; Babkina, Elena; Arefiev, Stanislav; Khairullin, Rustam

    2017-04-01

    Gas-emission craters (GEC) on Yamal peninsula, which occupied minds of researches for the last couple of years since first discovered in 2014, appeared to form on the place of specifically shaped mounds. There was a number of hypotheses involving pingo as an origin of these mounds. This arouse an interest in mapping pingo thus marking the areas of GEC formation risk. Our field research allows us to suggest that remote-sensing-based mapping of pingo may result in mix up of mounds of various origin. Thus, we started with classification of the mounds based on remote-sensing, field observations and survey from helicopter. Then we compared indicators of mounds of various classes to the properties of pre-crater mounds to conclude on their origin. Summarizing field experience, there are three main mound types on Yamal. (1) Outliers (remnant hills), separated from the main geomorphic landform by erosion. Often these mounds comprise polygonal blocks, kind of "baydzherakh". Their indicators are asymmetry (short gentle slope towards the main landform, and steep slope often descending into a small pond of thermokarst-nivation origin), often quadrangle or conic shape, and large size. (2) Pingo, appear within the khasyrei (drain lake basin); often are characterized by open cracks resulting from expansion of polygonal network formed when re-freezing of lake talik prior to pingo formation; old pingo may bear traces of collapse on the top, with depression which differs from the GEC by absence of parapet. (3) Frost-heave mounds (excluding pingo) may form on deep active layer, reducing due to moss-peat formation and forming ice lenses from an active layer water, usually they appear in the drainage hollows, valley bottoms, drain-lake basins periphery. These features are smaller than the first two types of mounds. Their tops as a rule are well vegetated. We were unable to find a single or a set of indicators unequivocally defining any specific mound type, thus indicators of pre-crater

  15. Redox stratification of an ancient lake in Gale crater, Mars.

    Science.gov (United States)

    Hurowitz, J A; Grotzinger, J P; Fischer, W W; McLennan, S M; Milliken, R E; Stein, N; Vasavada, A R; Blake, D F; Dehouck, E; Eigenbrode, J L; Fairén, A G; Frydenvang, J; Gellert, R; Grant, J A; Gupta, S; Herkenhoff, K E; Ming, D W; Rampe, E B; Schmidt, M E; Siebach, K L; Stack-Morgan, K; Sumner, D Y; Wiens, R C

    2017-06-02

    In 2012, NASA's Curiosity rover landed on Mars to assess its potential as a habitat for past life and investigate the paleoclimate record preserved by sedimentary rocks inside the ~150-kilometer-diameter Gale impact crater. Geological reconstructions from Curiosity rover data have revealed an ancient, habitable lake environment fed by rivers draining into the crater. We synthesize geochemical and mineralogical data from lake-bed mudstones collected during the first 1300 martian solar days of rover operations in Gale. We present evidence for lake redox stratification, established by depth-dependent variations in atmospheric oxidant and dissolved-solute concentrations. Paleoclimate proxy data indicate that a transition from colder to warmer climate conditions is preserved in the stratigraphy. Finally, a late phase of geochemical modification by saline fluids is recognized. Copyright © 2017, American Association for the Advancement of Science.

  16. Layers of 'Cabo Frio' in 'Victoria Crater' (False Color)

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.

  17. Layers of 'Cabo Frio' in 'Victoria Crater' (Stereo)

    Science.gov (United States)

    2006-01-01

    This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.

  18. A novel thermo-hydraulic coupling model to investigate the crater formation in electrical discharge machining

    Science.gov (United States)

    Tang, Jiajing; Yang, Xiaodong

    2017-09-01

    A novel thermo-hydraulic coupling model was proposed in this study to investigate the crater formation in electrical discharge machining (EDM). The temperature distribution of workpiece materials was included, and the crater formation process was explained from the perspective of hydrodynamic characteristics of the molten region. To better track the morphology of the crater and the movement of debris, the level-set method was introduced in this study. Simulation results showed that the crater appears shortly after the ignition of the discharge, and the molten material is removed by vaporizing in the initial stage, then by splashing at the following time. The driving force for the detachment of debris in the splashing removal stage comes from the extremely large pressure difference in the upper part of the molten region, and the morphology of the crater is also influenced by the shearing flow of molten material. It was found that the removal ratio of molten material is only about 7.63% under the studied conditions, leaving most to form the re-solidification layer on the surface of the crater. The size of the crater reaches the maximum at the end of discharge duration then experiences a slight reduction because of the reflux of molten material after the discharge. The results of single pulse discharge experiments showed that the morphologies and sizes between the simulation crater and actual crater are good at agreement, verifying the feasibility of the proposed thermo-hydraulic coupling model in explaining the mechanisms of crater formation in EDM.

  19. Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

    Science.gov (United States)

    Hui. Hejiu; Neal, Clive, R.; Shih, Chi-Yu; Nyquist, Laurence E.

    2012-01-01

    Pristine Apollo 14 (A-14) high-Al basalts represent the oldest volcanic deposits returned from the Moon [1,2] and are relatively enriched in Al2O3 (>11 wt%) compared to other mare basalts (7-11 wt%). Literature Rb-Sr isotopic data suggest there are at least three different eruption episodes for the A-14 high-Al basalts spanning the age range approx.4.3 Ga to approx.3.95 Ga [1,3]. Therefore, the high-Al basalts may record lunar mantle evolution between the formation of lunar crust (approx.4.4 Ga) and the main basin-filling mare volcanism (groups [5,6], and then regrouped into three with a possible fourth comprising 14072 based on the whole-rock incompatible trace element (ITE) ratios and Rb-Sr radiometric ages [7]. However, Rb-Sr ages of these basalts from different laboratories may not be consistent with each other because of the use of different 87Rb decay constants [8] and different isochron derivation methods over the last four decades. This study involved a literature search for Rb-Sr isotopic data previously reported for the high-Al basalts. With the re-calculated Rb-Sr radiometric ages, eruption episodes of A-14 high-Al basalts were determined, and their petrogenesis was investigated in light of the "new" Rb-Sr isotopic data and published trace element abundances of these basalts.

  20. Feldspar basalts in lunar soil and the nature of the lunar continents

    Science.gov (United States)

    Reid, A. M.; Ridley, W. I.; Harmon, R. S.; Warner, J.; Brett, R.; Jakes, P.; Brown, R. W.

    1974-01-01

    It is found that 25% on the Apollo-14 glasses have the same composition as the glasses in two samples taken from the Luna-16 column. The compositions are equivalent to feldspar basalt and anorthosite gabbro, and are similar to the feldspar basalts identified from Surveyor-7 analysis for lunar continents.

  1. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    Energy Technology Data Exchange (ETDEWEB)

    Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

    1980-05-23

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.

  2. Prokaryotic diversity, distribution, and insights into their role in biogeochemical cycling in marine basalts

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Olivia U.; Di Meo-Savoie, Carol A.; Van Nostrand, Joy D.; Zhou, Jizhong; Fisk, Martin R.; Giovannoni, Stephen J.

    2008-09-30

    We used molecular techniques to analyze basalts of varying ages that were collected from the East Pacific Rise, 9 oN, from the rift axis of the Juan de Fuca Ridge, and from neighboring seamounts. Cluster analysis of 16S rDNA Terminal Restriction Fragment Polymorphism data revealed that basalt endoliths are distinct from seawater and that communities clustered, to some degree, based on the age of the host rock. This age-based clustering suggests that alteration processes may affect community structure. Cloning and sequencing of bacterial and archaeal 16S rRNA genes revealed twelve different phyla and sub-phyla associated with basalts. These include the Gemmatimonadetes, Nitrospirae, the candidate phylum SBR1093 in the c, andin the Archaea Marine Benthic Group B, none of which have been previously reported in basalts. We delineated novel ocean crust clades in the gamma-Proteobacteria, Planctomycetes, and Actinobacteria that are composed entirely of basalt associated microflora, and may represent basalt ecotypes. Finally, microarray analysis of functional genes in basalt revealed that genes coding for previously unreported processes such as carbon fixation, methane-oxidation, methanogenesis, and nitrogen fixation are present, suggesting that basalts harbor previously unrecognized metabolic diversity. These novel processes could exert a profound influence on ocean chemistry.

  3. High-Ti type N-MORB parentage of basalts from the south Andaman ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    by Irvine and Baragar (1971) or MacDonald and. Katsura (1964) were not included here because of the considerable uncertainty that exists in such a classification scheme (see Sheth et al 2002 for more explanation). The Andaman ophiolite samples are mainly basalts (20 samples), with some basaltic andesites.

  4. Effect of basalt, silica sand and fly ash on the mechanical properties ...

    Indian Academy of Sciences (India)

    2018-05-17

    May 17, 2018 ... For this, we first manufactured binary PCs of epoxy/basalt ... Keywords. Polymer concrete; mechanical strength; mixture design; fly ash; silica sand; basalt. 1. .... To reduce the production cost of PCs, it is necessary to minimize ...

  5. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    International Nuclear Information System (INIS)

    Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

    1980-01-01

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive

  6. From mantle roots to surface eruptions: Cenozoic and Mesozoic continental basaltic magmatism

    Czech Academy of Sciences Publication Activity Database

    Kämpf, H.; Németh, K.; Puziewicz, J.; Mrlina, Jan; Geissler, W.H.

    2015-01-01

    Roč. 104, č. 8 (2015), s. 1909-1912 ISSN 1437-3254 Institutional support: RVO:67985530 Keywords : continental basaltic volcanism * BASALT 2013 conference * Cenozoic * Mesozoic Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.133, year: 2015

  7. Post-Columbia River Basalt Group stratigraphy and map compilation of the Columbia Plateau, Oregon

    International Nuclear Information System (INIS)

    Farooqui, S.M.; Bunker, R.C.; Thoms, R.E.; Clayton, D.C.; Bela, J.L.

    1981-01-01

    This report presents the results of reconnaissance mapping of sedimentary deposits and volcanic rocks overlying the Columbia River Basalt. The project area covers parts of the Dalles, Pendleton, Grangeville, Baker, Canyon City, and Bend. The mapping was done to provide stratigraphic data on the sedimentary deposits and volcanic rocks overlying the Columbia River Basalt Group. 160 refs., 16 figs., 1 tab

  8. Glass and mineral chemistry of northern central Indian ridge basalts: Compositional diversity and petrogenetic significance

    Digital Repository Service at National Institute of Oceanography (India)

    Ray, Dwijesh; Banerjee, R.; Iyer, S.D.; Basavalingu, B.; Mukhopadhyay, S.

    -88)), diopside (Wo sub(45-51), En sub(25-37), Fs sub14-24)), and titanomagnetite (FeO sub(t) approx. 63.5 wt% and Ti0 sub(2) approx. 22.69 wt%). The whole-rock composition of these basalts has similar Mg [mole Mg/mole(Mg+Fe sup(2+))] (VT basalt: approx. 0...

  9. Martian Cratering 7: The Role of Impact Gardening

    Science.gov (United States)

    Hartmann, William K.; Anguita, Jorge; de la Casa, Miguel A.; Berman, Daniel C.; Ryan, Eileen V.

    2001-01-01

    Viking-era researchers concluded that impact craters of diameter Dduricrust at Viking and Pathfinder sites demonstrates the cementing process. These results affect lander/rover searches for intact ancient deposits. The upper tens of meters of exposed Noachian units cannot survive today in a pristine state. Intact Noachian deposits might best be found in cliffside strata, or in recently exhumed regions. The hematite-rich areas found in Terra Meridiani by the Mars Global Surveyor are probably examples of the latter.

  10. Continued monitoring of aeolian activity within Herschel Crater, Mars</