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Sample records for volcanic mounds gas

  1. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  2. 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

  3. Volcanism and Oil & Gas In Northeast China

    Institute of Scientific and Technical Information of China (English)

    Shan Xuanlong

    2000-01-01

    Based on study on the relation with volcanic rock and oil & gas in Songliao Basin and Liaohe Basin in northeast China, author proposes that material from deep by volcanism enrichs the resources in basins, that heat by volcanism promotes organic matter transforming to oil and gas, that volcanic reservoir is fracture, vesicular, solution pore, intercrystal pore.Lava facies and pyroclastic facies are favourable reservoir. Mesozoic volcanic reservoir is majority of intermediate, acid rock,but Cenozoic volcanic reservoir is majority of basalt. Types of oil and gas pool relating to volcanic rock include volcanic fracture pool, volcanic unconformity pool, volcanic rock - screened pool, volcanic darpe structural pool.

  4. Topographic features of gas hydrate mounds of shallow gas hydrate areas in Joetsu Basin , eastern margin of Japan Sea

    Science.gov (United States)

    Hiromatsu, M.; Machiyama, H.; Matsumoto, R.

    2010-12-01

    Mega pockmarks and mounds, both of which are 300m to 500m in diamater and 30m to 40 m deep or high, characterize the Umitaka Spur and Joetsu Knoll of the Joetsu Basin. A number of pockmarks and mounds develop in NNE to SSW direction parallel to the general trend of mobile belt along the eastern margin of Japan Sea, suggesting that the topography has been strongly controlled by regional tectonics. Seismic profiles have revealed well-developed chaotic to transparent zones (gas chimneys) in the area of pockmarks and mounds, from which a number of active methane plumes stand up to 700m above sea floor. Ultra-high resolution bathymetric data and reflection images were acquired by Multi Beam Echo Sounder (MBES) and Side Scan Sonar (SSS) of the AUV "URASHIMA” during the YK10-08 cruise of R/V Yokosuka (JAMSTEC), July 2010. Based on mosaic images of MBES and SSS, we could identify several types of the hydrate mounds over gas chimney zones. Some are represented as a smooth and low bulge without strong reflections of background level, but the others show rough and uneven topography, featured by a few meter scale depressions, crevasses and minor ridges with strong reflector images, indicating the development of hard ground. Such strong reflectors are due to carbonate crusts and concretions and gas hydrate exposures as observed by ROV . Micro-topographic features are likely to represent a growth stage of hydrate mounds, and perhaps the accumulation of shallow gas hydrates. MBES and SSS onboard AUV are powerful tools to identify gas hydrate accumulation and evolution of shallow gas hydrate system.

  5. Association among active seafloor deformation, mound formation, and gas hydrate growth and accumulation within the seafloor of the Santa Monica Basin, offshore California

    Science.gov (United States)

    Paull, C.K.; Normark, W.R.; Ussler, W.; Caress, D.W.; Keaten, R.

    2008-01-01

    Seafloor blister-like mounds, methane migration and gas hydrate formation were investigated through detailed seafloor surveys in Santa Monica Basin, offshore of Los Angeles, California. Two distinct deep-water (??? 800??m water depth) topographic mounds were surveyed using an autonomous underwater vehicle (carrying a multibeam sonar and a chirp sub-bottom profiler) and one of these was explored with the remotely operated vehicle Tiburon. The mounds are > 10??m high and > 100??m wide dome-shaped bathymetric features. These mounds protrude from crests of broad anticlines (~ 20??m high and 1 to 3??km long) formed within latest Quaternary-aged seafloor sediment associated with compression between lateral offsets in regional faults. No allochthonous sediments were observed on the mounds, except slumped material off the steep slopes of the mounds. Continuous streams of methane gas bubbles emanate from the crest of the northeastern mound, and extensive methane-derived authigenic carbonate pavements and chemosynthetic communities mantle the mound surface. The large local vertical displacements needed to produce these mounds suggests a corresponding net mass accumulation has occurred within the immediate subsurface. Formation and accumulation of pure gas hydrate lenses in the subsurface is proposed as a mechanism to blister the seafloor and form these mounds. ?? 2008 Elsevier B.V. All rights reserved.

  6. Deep Explosive Volcanism on the Gakkel Ridge and Seismological Constraints on Shallow Recharge at TAG Active Mound

    Science.gov (United States)

    2013-02-01

    in the mantle, where rigid tectonic plates move apart and new seafloor material rises to fill the vacant space. The generation of new plate material...focus on shallow seismic activity beneath the hydrothermal mound. The OBS network also detected a large number of local and regional tectonic events...hydrothermal mound with the larger-scale seismicity associated with tectonic extension on the active detachment fault [deMartin et al., 2007]. Thermal

  7. Visualising volcanic gas plumes with virtual globes

    Science.gov (United States)

    Wright, T. E.; Burton, M.; Pyle, D. M.; Caltabiano, T.

    2009-09-01

    The recent availability of small, cheap ultraviolet spectrometers has facilitated the rapid deployment of automated networks of scanning instruments at several volcanoes, measuring volcanic SO 2 gas flux at high frequency. These networks open up a range of other applications, including tomographic reconstruction of the gas distribution which is of potential use for both risk mitigation, particularly to air traffic, and environmental impact modelling. Here we present a methodology for visualising reconstructed plumes using virtual globes, such as Google Earth, which allows animations of the evolution of the gas plume to be displayed and easily shared on a common platform. We detail the process used to convert tomographically reconstructed cross-sections into animated gas plume models, describe how this process is automated and present results from the scanning network around Mt. Etna, Sicily. We achieved an average rate of one frame every 12 min, providing a good visual representation of the plume which can be examined from all angles. In creating these models, an approximation to turbulent diffusion in the atmosphere was required. To this end we derived the value of the turbulent diffusion coefficient for quiescent conditions near Etna to be around 200- 500m2s-1.

  8. Evidence for Freshwater Discharge at a Gas Hydrate-Bearing Seafloor Mound on the Beaufort Sea Continental Slope

    Science.gov (United States)

    Pohlman, J.; Lorenson, T. D.; Hart, P. E.; Ruppel, C. D.; Joseph, C.; Torres, M. E.; Edwards, B. D.

    2011-12-01

    A deep-water (~2.5 km water depth) seafloor mound located ~150 km offshore of the North Slope Alaska, informally named the Canning Seafloor Mound (CSM), contains a documented occurrence of gas hydrate; the first from the Beaufort Sea. Gases and porewater extracted from cores taken at the CSM summit several months after core recovery provided surprisingly consistent and outstanding results. Gases migrating into the structure are likely a mixture of primary microbial gas formed by carbonate reduction and secondary microbial gas formed from degraded thermogenic gases, linking the system to deep oil and gas generation (see companion abstract by Lorenson et al.). Pore fluids extracted from the base of the 572 cm-long hydrate-bearing core had chloride values as low as 160 mM, which equates to an ~80% freshwater contribution. Low chloride values, often interpreted as a product of gas hydrate dissociation in hydrate-bearing cores, were coincident with sulfate values in excess of 1 mM and as high as 22 mM (seawater is ~28mM). High sulfate concentrations generally indicate an absence of methane, and, thus, gas hydrate; therefore, an allochthonous source of freshwater is required. Potential sources are clay mineral dehydration, clay membrane filtration and/or a meteoric water influx. Several lines of evidence indicate the Canning Seafloor Mound is connected to either a deep, landward freshwater aquifer or to an unusually fresh oil field brine. First, Na/Cl ratios decrease from marine (~0.86) near the seafloor to distinctly higher values of 1.20 at the bottom of the core. Second, clay dehydration and ion filtration processes have not, to our knowledge, yielded fluids as fresh as measured in these near-seafloor sediments. Third, and most importantly, δ18O-δD systematics of fluid end members are entirely consistent with a meteoric water source and inconsistent with trends expected for either gas hydrate dissociation, smectite to illite clay dewatering or ion filtration

  9. Monitoring gas emissions can help forecast volcanic eruptions

    Science.gov (United States)

    Kern, Christoph; Maarten de Moor,; Bo Galle,

    2015-01-01

    As magma ascends in active volcanoes, dissolved volatiles partition from melt into a gas phase, rise, and are released into the atmosphere from volcanic vents. The major components of high-temperature volcanic gas are typically water vapor, carbon dioxide, and sulfur dioxide. 

  10. Beaufort Sea deep-water gas hydrate recovery from a seafloor mound in a region of widespread BSR occurrence

    Science.gov (United States)

    Hart, Patrick E.; Pohlman, John W.; Lorenson, T.D.; Edwards, Brian D.

    2011-01-01

    Gas hydrate was recovered from the Alaskan Beaufort Sea slope north of Camden Bay in August 2010 during a U.S. Coast Guard Cutter Healy expedition (USCG cruise ID HLY1002) under the direction of the U.S. Geological Survey (USGS). Interpretation of multichannel seismic (MCS) reflection data collected in 1977 by the USGS across the Beaufort Sea continental margin identified a regional bottom simulating reflection (BSR), indicating that a large segment of the Beaufort Sea slope is underlain by gas hydrate. During HLY1002, gas hydrate was sampled by serendipity with a piston core targeting a steep-sided bathymetric high originally thought to be an outcrop of older, exposed strata. The feature cored is an approximately 1100m diameter, 130 m high conical mound, referred to here as the Canning Seafloor Mound (CSM), which overlies the crest of a buried anticline in a region of sub-parallel compressional folds beneath the eastern Beaufort outer slope. An MCS profile shows a prominent BSR upslope and downslope from the mound. The absence of a BSR beneath the CSM and occurrence of gas hydrate near the summit indicates that free gas has migrated via deep-rooted thrust faults or by structural focusing up the flanks of the anticline to the seafloor. Gas hydrate recovered from near the CSM summit at a subbottom depth of about 5.7 meters in a water depth of 2538 m was of nodular and vein-filling morphology. Although the hydrate was not preserved, residual gas from the core liner contained >95% methane by volume when corrected for atmospheric contamination. The presence of trace C4+hydrocarbons (inflation of the seafloor caused by formation and accumulation of shallow hydrate lenses is also a likely factor in CSM growth. Pore water analysis shows the sulfate-methane transition to be very shallow (0-1 mbsf), also supporting an active high-flux interpretation. Pore water with chloride concentrations as low as 160 mM suggest fluid migration pathways may extend to the mound from buried

  11. Volcanic gas composition, metal dispersion and deposition during explosive volcanic eruptions on the Moon

    Science.gov (United States)

    Renggli, C. J.; King, P. L.; Henley, R. W.; Norman, M. D.

    2017-06-01

    The transport of metals in volcanic gases on the Moon differs greatly from their transport on the Earth because metal speciation depends largely on gas composition, temperature, pressure and oxidation state. We present a new thermochemical model for the major and trace element composition of lunar volcanic gas during pyroclastic eruptions of picritic magmas calculated at 200-1500 °C and over 10-9-103 bar. Using published volatile component concentrations in picritic lunar glasses, we have calculated the speciation of major elements (H, O, C, Cl, S and F) in the coexisting volcanic gas as the eruption proceeds. The most abundant gases are CO, H2, H2S, COS and S2, with a transition from predominantly triatomic gases to diatomic gases with increasing temperatures and decreasing pressures. Hydrogen occurs as H2, H2S, H2S2, HCl, and HF, with H2 making up 0.5-0.8 mol fractions of the total H. Water (H2O) concentrations are at trace levels, which implies that H-species other than H2O need to be considered in lunar melts and estimates of the bulk lunar composition. The Cl and S contents of the gas control metal chloride gas species, and sulfide gas and precipitated solid species. We calculate the speciation of trace metals (Zn, Ga, Cu, Pb, Ni, Fe) in the gas phase, and also the pressure and temperature conditions at which solids form from the gas. During initial stages of the eruption, elemental gases are the dominant metal species. As the gas loses heat, chloride and sulfide species become more abundant. Our chemical speciation model is applied to a lunar pyroclastic eruption model with isentropic gas decompression. The relative abundances of the deposited metal-bearing solids with distance from the vent are predicted for slow cooling rates (<5 °C/s). Close to a volcanic vent we predict native metals are deposited, whereas metal sulfides dominate with increasing distance from the vent. Finally, the lunar gas speciation model is compared with the speciation of a H2O-, CO

  12. Growth of gas hydrate mounds and gas chimneys of the eastern margin of Japan Sea as revealed by MBES, SSS and SBP of AUV

    Science.gov (United States)

    Matsumoto, R.; Satoh, M.; Hiromatsu, M.; Tomaru, H.; Machiyama, H.

    2010-12-01

    A series of PC, ROV and SCS surveys to study the origin and evolution of gas hydrate systems along the eastern margin of Japan Sea have identified a number of shallow GH accumulations on the mounds, 300m to 500m in diameter and 30m to 40m high, on the Umitaka spur and Joetsu knoll in Joetsu basin with the WD of 880m to 1200m (Matsumoto et al., 2005; 2009). All of the hydrate mounds develop on gas chimneys as recognized by seismic profiles, and some are associated with gigantic methane plumes, 600m to 700m high. Multi Beam Echo Sounder (MBES), Side Scan Sonar (SSS) and Sub-Bottom Profiler (SBP) of AUV Urashima have revealed ultra-high resolution topographic features and subsurface structures of the mounds and adjacent areas during the JAMSTEC YK10-08 cruise, July 2010. AUV Urashima ran over the spur and knoll at 50m to 80m above seafloor at a cruising speed of 2.4 knots. MBES and SSS mosaics demonstrate two types of mounds. One is a low swell with smooth surface and weak reflectance, while the other is characterized by rough and uneven topographic features with strong SSS images due to incrustation by methane-induced carbonate concretions and gas hydrates. SBP provides clear stratigraphic and structural relations down to 50mbsf to 80mbsf and recognizes three stratigraphic units as I: upper massive unit (5-10m thick), II: middle evenly bedded unit (15-25m thick) and III: lower slightly bedded unit (> 15-25m thick). Gas chimneys grow up toward the seafloor through Units III, II, and I. When the ceiling of gas chimney stays within Unit III or II, the mound above the chimney is either low swell or nearly flat, while the swell grows up higher when the ceiling reaches to Unit I or the seafloor. Eventually, the ceiling breaks through the seafloor and protrudes to form GH mound up to 40m to 50m high, and then start to decay probably due to mechanical collapse and chemical dissolution of gas hydrates. The ceiling of gas chimneys is often represented by high amplitude, uneven

  13. Evidence of mud volcanism rooted in gas hydrate-rich cryosphere linking surface and subsurface for the search for life on Mars

    Science.gov (United States)

    De Toffoli, Barbara; Pozzobon, Riccardo; Mazzarini, Francesco; Massironi, Matteo; Cremonese, Gabriele

    2017-04-01

    and brought to the surface with the sediments a putative extinct or extant deep biosphere. In conclusion, on the base of this study, emerged that: (i) mud volcanoes are the best terrestrial analogs for the considered Martian mounds, (ii) there is a recurrent specific subsurface environment where the phenomenon may be triggered and it is the base of gas hydrate-rich cryosphere for all the study areas and (iii) mud volcanism seems to be, at least partially, a geologically recent event in terms of planet thermal evolution timespan. In light of these results, the CaSSIS camera, onboard the Trace Gas Orbiter ExoMARS mission, will provide new images of these features to improve and widen the understanding of the mechanisms that lie behind this phenomenon.

  14. Volcanic gas impacts on vegetation at Turrialba Volcano, Costa Rica

    Science.gov (United States)

    Teasdale, R.; Jenkins, M.; Pushnik, J.; Houpis, J. L.; Brown, D. L.

    2010-12-01

    Turrialba volcano is an active composite stratovolcano that is located approximately 40 km east of San Jose, Costa Rica. Seismic activity and degassing have increased since 2005, and gas compositions reflect further increased activity since 2007 peaking in January 2010 with a phreatic eruption. Gas fumes dispersed by trade winds toward the west, northwest, and southwest flanks of Turrialba volcano have caused significant vegetation kill zones, in areas important to local agriculture, including dairy pastures and potato fields, wildlife and human populations. In addition to extensive vegetative degradation is the potential for soil and water contamination and soil erosion. Summit fumarole temperatures have been measured over 200 degrees C and gas emissions are dominated by SO2; gas and vapor plumes reach up to 2 km (fumaroles and gases are measured regularly by OVSICORI-UNA). A recent network of passive air sampling, monitoring of water temperatures of hydrothermal systems, and soil pH measurements coupled with measurement of the physiological status of surrounding plants using gas exchange and fluorescence measurements to: (1) identify physiological correlations between leaf-level gas exchange and chlorophyll fluorescence measurements of plants under long term stress induced by the volcanic gas emissions, and (2) use measurements in tandem with remotely sensed reflectance-derived fluorescence ratio indices to track natural photo inhibition caused by volcanic gas emissions, for use in monitoring plant stress and photosynthetic function. Results may prove helpful in developing potential land management strategies to maintain the biological health of the area.

  15. Integrating volcanic gas monitoring with other geophysical networks in Iceland

    Science.gov (United States)

    Pfeffer, Melissa A.

    2017-04-01

    The Icelandic Meteorological Office/Icelandic Volcano Observatory is rapidly developing and improving the use of gas measurements as a tool for pre- and syn-eruptive monitoring within Iceland. Observations of deformation, seismicity, hydrological properties, and gas emissions, united within an integrated approach, can provide improved understanding of subsurface magma movements. This is critical to evaluate signals prior to and during volcanic eruptions, issue timely eruption warnings, forecast eruption behavior, and assess volcanic hazards. Gas measurements in Iceland need to be processed to account for the high degree of gas composition alteration due to interaction with external water and rocks. Deeply-sourced magmatic gases undergo reactions and modifications as they move to the surface that exercise a strong control on the composition of surface emissions. These modifications are particularly strong at ice-capped volcanoes where most surface gases are dissolved in glacial meltwater. Models are used to project backwards from surface gas measurements to what the magmatic gas composition was prior to upward migration. After the pristine magma gas composition has been determined, it is used together with fluid compositions measured in mineral hosted melt inclusions to calculate magmatic properties to understand magma storage and migration and to discern if there have been changes in the volcanic system. The properties derived from surface gas measurements can be used as input to models interpreting deformation and seismic observations, and can be used as an additional, independent observation when interpreting hydrological and seismic changes. An integrated approach aids with determining whether observed hydro/geological changes can be due to the presence of shallow magma. Constraints on parameters such as magma gas content, viscosity and compressibility can be provided by the approach described above, which can be utilized syn-eruptively to help explain

  16. Massive Dissociation of Subsurface Gas Hydrates and Collapse of Gas Hydrate Mounds during the LGM in the Eastern Margin of Japan Sea: Evidence from Benthic Forams and U/Th ages of Authigenic Carbonates

    Science.gov (United States)

    Matsumoto, R.; Takeuchi, E.; Sanno, R.

    2008-12-01

    A number of gigantic methane plumes, ca. 600 m high, and massive blocks of gas hydrate, ca. 0.5 m x 1.0 m, have been observed on the Umitaka spur and Joetsu knoll, eastern margin of Japan Sea. Large pockmarks and mounds, ca. 0.5 km in diameter, develop on the spur and knoll. The mounds exhibit rough morphological features characterized by small valleys of 5m wide, steep cliffs, crater-like depressions of 10 m in diameter, and scattered carbonate nodules and crusts of various size and shape with occasional gas hydrate blocks and veins and gas venting. To the contrary, pockmarks are inactive, partly filled by well-stratified mud without any indication of gas venting. 2D and 3D seismic surveys have recognized widely distributed BSRs at around 150 mbsf over the spur and knoll. Seismic profiles delineated deep gas chimney structures below the pockmarks and mounds. Unusual pull-up structures within gas chimneys indicate massive accumulation of gas hydrate. All these findings are likely to suggest that massive hydrate deposits both in gas chimneys at depths and hydrate mounds on the spur and knoll were collapsed and floated up to the sea surface, leaving big holes (= pockmarks) on the seafloor. Quantitative analysis of foraminiferal assemblage has revealed that the well laminated, burrow-free 17 to 22 ka sediments are substantially barren for benthic forams but for unusual species which has been believed to survive under high methane environments. Shells of such a few benthic formas from around 20 ka sediments are anomalously depleted in C-13. U-Th ages of authigenic carbonates of CH4-induced carbonate nodules and crusts are likely to center around 20 ka. Above line of evidences all suggest that gas hydrate system was collapsed and methane fluxes were enhanced during the last glacial maximum (LGM), presumably due to low stand of sea level and pressure release. Broken gas hydrate blocks are expected to float up to the sea surface to supply significant amount of methane to

  17. Impacts from Partial Removal of Decommissioned Oil and Gas Platforms on Fish Biomass and Production on the Remaining Platform Structure and Surrounding Shell Mounds.

    Directory of Open Access Journals (Sweden)

    Jeremy T Claisse

    Full Text Available When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on all but one platform off the coast of California. On average 80% of fish biomass and 86% of secondary fish production would be retained after partial removal, with above 90% retention expected for both metrics on many platforms. Partial removal would likely result in the loss of fish biomass and production for species typically found residing in the shallow portions of the platform structure. However, these fishes generally represent a small proportion of the fishes associated with these platforms. More characteristic of platform fauna are the primarily deeper-dwelling rockfishes (genus Sebastes. "Shell mounds" are biogenic reefs that surround some of these platforms resulting from an accumulation of mollusk shells that have fallen from the shallow areas of the platforms mostly above the depth of partial removal. We found that shell mounds are moderately productive fish habitats, similar to or greater than natural rocky reefs in the region at comparable depths. The complexity and areal extent of these biogenic habitats, and the associated fish biomass and production, will likely be reduced after either partial or complete platform removal. Habitat augmentation by placing the partially removed platform superstructure or some other additional habitat enrichment material (e.g., rock boulders on the seafloor adjacent to the base of partially removed platforms provides additional options to enhance fish production, potentially mitigating reductions in shell mound habitat.

  18. Geologic Features of Wangjiatun Deep Gas Reservoirs of Volcanic Rock in Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    SHAN Xuanlong; CHEN Shumin; WU Dawei; Zang Yudong

    2001-01-01

    Wangjiatun gas pool is located at the north part of Xujiaweizi in Songliao basin. Commercial gas flow has been found in the intermediate and acid volcanic rock of upper Jurassic - lower Cretaceous, which makes a breakthrough in deep nature gas prospecting in Songliao basin. The deep natural gas entrapment regularity is discussed in the paper by the study of deep strata, structure and reservoir. Andesite, rhyolite and little pyroclastic rock are the main reservoirs. There are two types of volcanic reservoir space assemblage in this area: the pore and fissure and the pure fissure. Changes had taken place for volcanic reservoir space during long geologic time, which was controlled by tectonic movement and geologic environment.The developed degree of reservoir space was controlled by tectonic movement, weathering and filtering, corrosion and Filling. There are three types of source- reservoir-caprock assemblage in this area: lower source- upper reservoir model,upper source - lower reservoir model and lateral change model. Mudstone in Dengluoku formation and the compacted volcanic rock of upper Jurassic - lower Cretaceous are the caprock for deep gas reservoirs. Dark mudstone of deep lacustrine facies in Shahezi formation and lower part of Dengluoku formation are the source rock of deep gas. It can be concluded that deep gas pools are mainly volcanic lithologic reservoirs.

  19. Automatic semi-continuous accumulation chamber for diffuse gas emissions monitoring in volcanic and non-volcanic areas

    Science.gov (United States)

    Lelli, Matteo; Raco, Brunella; Norelli, Francesco; Virgili, Giorgio; Continanza, Davide

    2016-04-01

    Since various decades the accumulation chamber method is intensively used in monitoring activities of diffuse gas emissions in volcanic areas. Although some improvements have been performed in terms of sensitivity and reproducibility of the detectors, the equipment used for measurement of gas emissions temporal variation usually requires expensive and bulky equipment. The unit described in this work is a low cost, easy to install-and-manage instrument that will make possible the creation of low-cost monitoring networks. The Non-Dispersive Infrared detector used has a concentration range of 0-5% CO2, but the substitution with other detector (range 0-5000 ppm) is possible and very easy. Power supply unit has a 12V, 7Ah battery, which is recharged by a 35W solar panel (equipped with charge regulator). The control unit contains a custom programmed CPU and the remote transmission is assured by a GPRS modem. The chamber is activated by DataLogger unit, using a linear actuator between the closed position (sampling) and closed position (idle). A probe for the measure of soil temperature, soil electrical conductivity, soil volumetric water content, air pressure and air temperature is assembled on the device, which is already arranged for the connection of others external sensors, including an automatic weather station. The automatic station has been tested on the field at Lipari island (Sicily, Italy) during a period of three months, performing CO2 flux measurement (and also weather parameters), each 1 hour. The possibility to measure in semi-continuous mode, and at the same time, the gas fluxes from soil and many external parameters, helps the time series analysis aimed to the identification of gas flux anomalies due to variations in deep system (e.g. onset of volcanic crises) from those triggered by external conditions.

  20. Ground Based Ultraviolet Remote Sensing of Volcanic Gas Plumes

    Science.gov (United States)

    Kantzas, Euripides P.; McGonigle, Andrew J. S.

    2008-01-01

    Ultraviolet spectroscopy has been implemented for over thirty years to monitor volcanic SO2 emissions. These data have provided valuable information concerning underground magmatic conditions, which have been of utility in eruption forecasting efforts. During the last decade the traditionally used correlation spectrometers have been upgraded with miniature USB coupled UV spectrometers, opening a series of exciting new empirical possibilities for understanding volcanoes and their impacts upon the atmosphere. Here we review these technological developments, in addition to the scientific insights they have precipitated, covering the strengths and current limitations of this approach.

  1. Gas venting rates from submarine hydrothermal areas around the island of Milos, Hellenic Volcanic Arc

    Science.gov (United States)

    Dando, P. R.; Hughes, J. A.; Leahy, Y.; Niven, S. J.; Taylor, L. J.; Smith, C.

    1995-07-01

    Gas seeps were located, by echo sounding, SCUBA divers and ROV observations, at hydrothermal sites around the island of Milos, in the Hellenic Volcanic Arc. Samples were collected by SCUBA divers and by a ROV from water depths between 3 and 110 m. Fifty-six flow rates from 39 individual seeps were measured and these ranged from 0.2 to 18.51 h -1 at the depth of collection. The major component, 54.9-91.9% of the gas, was carbon dioxide. Hydrogen (≤3%), methane (≤9.7%) and hydrogen sulphide (≤8.1%) were also measured. Hydrothermal free gas fluxes from the submarine hydrothermal areas around Milos were estimated to be greater than 10 10 moles y -1. It was concluded that submarine gas seeps along volcanic island arcs may be an important carbon dioxide source.

  2. Evolved Gas Measurements Planned for the Lower Layers of the Gale Crater Mound with the Sample Analysis at Mars Instrument Suite

    Science.gov (United States)

    Mahaffy, Paul; Brunner, Anna; McAdam, Amy; Franz, Heather; Conrad, Pamela; Webster, Chris; Cabane, Michel

    2009-01-01

    The lower mound strata of Gale Crater provide a diverse set of chemical environments for exploration by the varied tools of the Curiosity Rover of the Mars Science Laboratory (MSL) Mission. Orbital imaging and spectroscopy clearly reveal distinct layers of hydrated minerals, sulfates, and clays with abundant evidence of a variety of fluvial processes. The three instruments of the MSL Sample Analysis at aMars (SAM) investigation, the Quadrupole Mass Spectrometer (QMS), the Tunable Laser Spectrometer (TLS), and the Gas Chromatograph (GC) are designed to analyze either atmospheric gases or volatiles thermally evolved or chemically extracted from powdered rock or soil. The presence or absence of organic compounds in these layers is of great interest since such an in situ search for this type of record has not been successfully implemented since the mid-60s Viking GCMS experiments. However, regardless of the outcome of the analysis for organics, the abundance and isotopic composition of thermally evolved inorganic compounds should also provide a rich data set to complement the mineralogical and elemental information provided by other MSL instruments. In addition, these evolved gas analysis (EGA) experiments will help test sedimentary models proposed by Malin and Edgett (2000) and then further developed by Milliken et al (2010) for Gale Crater. In the SAM EGA experiments the evolution temperatures of H2O, CO2, SO2, O2, or other simple compounds as the samples are heated in a helium stream to 1000 C provides information on mineral types and their associations. The isotopic composition of O, H, C, and S can be precisely determined in several evolved compounds and compared with the present day atmosphere. Such SAM results might be able to test mineralogical evidence of changing sedimentary and alteration processes over an extended period of time. For example, Bibring et al (2006) have suggested such a major shift from early nonacidic to later acidic alteration. We will

  3. Long-term autonomous volcanic gas monitoring with Multi-GAS at Mount St. Helens, Washington, and Augustine Volcano, Alaska

    Science.gov (United States)

    Kelly, P. J.; Ketner, D. M.; Kern, C.; Lahusen, R. G.; Lockett, C.; Parker, T.; Paskievitch, J.; Pauk, B.; Rinehart, A.; Werner, C. A.

    2015-12-01

    In recent years, the USGS Volcano Hazards Program has worked to implement continuous real-time in situ volcanic gas monitoring at volcanoes in the Cascade Range and Alaska. The main goal of this ongoing effort is to better link the compositions of volcanic gases to other real-time monitoring data, such as seismicity and deformation, in order to improve baseline monitoring and early detection of volcanic unrest. Due to the remote and difficult-to-access nature of volcanic-gas monitoring sites in the Cascades and Alaska, we developed Multi-GAS instruments that can operate unattended for long periods of time with minimal direct maintenance from field personnel. Our Multi-GAS stations measure H2O, CO2, SO2, and H2S gas concentrations, are comprised entirely of commercial off-the-shelf components, and are powered by small solar energy systems. One notable feature of our Multi-GAS stations is that they include a unique capability to perform automated CO2, SO2, and H2S sensor verifications using portable gas standards while deployed in the field, thereby allowing for rigorous tracking of sensor performances. In addition, we have developed novel onboard data-processing routines that allow diagnostic and monitoring data - including gas ratios (e.g. CO2/SO2) - to be streamed in real time to internal observatory and public web pages without user input. Here we present over one year of continuous data from a permanent Multi-GAS station installed in August 2014 in the crater of Mount St. Helens, Washington, and several months of data from a station installed near the summit of Augustine Volcano, Alaska in June 2015. Data from the Mount St. Helens Multi-GAS station has been streaming to a public USGS site since early 2015, a first for a permanent Multi-GAS site. Neither station has detected significant changes in gas concentrations or compositions since they were installed, consistent with low levels of seismicity and deformation.

  4. Integration and Testing of Miniaturized Volcanic Gas-Sensing Instruments on UAS Platforms

    Science.gov (United States)

    Lopez, T. M.; Kern, C.; Diaz, J. A.; Vanderwaal, S. J.; Levy, A.

    2015-12-01

    Volcanologists measure the concentrations and emission rates of gases emitted from active volcanoes to understand magmatic processes, which aids in eruption forecasting, and to evaluate air quality for human and environmental health. Both of these applications become particularly important during periods of unusually high volcanic unrest when it is typically hazardous to approach a given volcano. Unmanned aerial systems (UASs) represent a promising platform for continued gas measurements during unrest, while reducing the risk to volcanologists. Two miniature gas-sensing instruments have been developed specifically for integration onto small UAS platforms. Both instruments weigh 1 kg or less, including integrated power. The microDOAS instrument is an upward-looking UV/vis spectrometer that measures the spectral absorption signature of SO2 and certain halogen oxides in scattered solar radiation. By flying beneath a volcanic plume, the instrument can measure the SO2 content in the plume cross-section which can be used to determine the SO2 emission rate. The miniGas instrument is flown within the volcanic plume and records in situ concentrations of CO2, SO2 and H2S, as well as atmospheric temperature, pressure, relative humidity and GPS location. All data are telemetered back to the base station to immediately alert the operator of potentially hazardous conditions. Both instruments have been successfully tested at active volcanoes in Alaska and Costa Rica and were integrated onto small ACUASI Ptarmigan hexacopters. A test mission was conducted at the Poker Flat Research Range in Alaska. During this experiment both instruments were successfully flown in flight patterns typical of manned volcanic gas measurements and new UAV-specific measurement strategies were developed. Here we describe the instruments and platforms employed, our experimental results and observations, and make recommendations for application to volcanic settings.

  5. The Bahrain Burial Mound Project

    DEFF Research Database (Denmark)

    Laursen, Steffen; Johansen, Kasper Lambert

    2007-01-01

    the majority of burial mounds have been removed to make way for roads and housing, and in this process about 8000 mounds have been excavated; of these only c. 265 have been published. In 2006 the Bahrain Directorate for Culture & National Heritage and Moesgaard Museum decided on a collaborative project...... focussed on the Bahrain burial mounds. Within the framework of the Burial Mound Project aerial photos from 1959 have been orto-rectified and geo-referenced and so far a GIS-based digital map representing more than 60.000 mounds have been completed. With respect to the thousands of excavated mounds the huge...... process of linking relevant information to the mounds have been initiated in the course of which excavation data of individual monument is being fed into a relational database. Our preliminary study of the digital maps of the mound cemeteries has revealed an abundance of interesting patterns...

  6. Volcanic Gas Measurements During the 2004 Unrest at Mount St. Helens

    Science.gov (United States)

    McGee, K. A.; Gerlach, T. M.; Doukas, M. P.; Sutton, A. J.

    2004-12-01

    Volcanic gas observations during the 2004 unrest at Mount St. Helens began with helicopter measurements on September 27 and shifted to fixed-wing aircraft measurements on October 7. Helicopter measurements were done by downwind plume profiling at the crater rim and crater breach, orbiting the dome and cross traversing the top of the dome. Fixed-wing aircraft measurements consisted of profiling the downwind plume as it spilled over the crater rim. Target gases included CO2, SO2, and H2S measured by LI-COR, COSPEC and Interscan analyzers. These measurements defined three periods of volcanic degassing: (a) an initial period of negligible volcanic degassing characterized by scrubbing or sealing-in of all gases; (b) an intermediate period of wet volcanic degassing when gas scrubbing dominated volcanic degassing; and (c) a period of dry volcanic degassing when volcanic degassing exceeded gas scrubbing. Measurements during the September 27-30 period of negligible volcanic degassing showed little or no CO2 above atmospheric levels; SO2 and H2S were not detected. The absence of these gases implies fairly complete gas scrubbing at high water to gas mass ratios (greater than 100) or confinement of the gases by post-1986 sealing of gas transport channel ways. Scrubbing seems likely to have dominated sealing; the high rates of concurrent seismicity and deformation favored reestablishment of transport along fractures, and the unrest followed a period with an unusually large potential for groundwater recharge. No August-September interval since the cessation of dome-building eruptions in 1986 has had heavier rainfall than in 2004, and growth of the crater glacier since 1986 has increased the amount of water available for recharge in late summer. Measurements during the period of wet volcanic degassing that began on October 1 after the first steam and ash eruption showed an increase in the frequency and size of CO2 peaks together with the increasingly common detection of H2S

  7. Modern carbonate mound systems

    Science.gov (United States)

    Henriet, J. P.; Dullo, C.

    2003-04-01

    Carbonate mounds are prominent features throughout the geological record. In many hydrocarbon provinces, they form prime reservoir structures. But recent investigations have increasingly reported occurrences of large mound clusters at the surface of the seabed, or buried at shallow depth on modern ocean margins, and in particular in basins rich in hydrocarbons. Such exciting new observations along the West-European margin are promising for elucidating the setting and environment of modern carbonate mounds, but at the same time they confront us with puzzling or sometimes contradictory observations in the quest for their genesis. Spectacular cold-water coral communities have colonized such mounds, but convincing arguments for recognizing them as prime builders are still lacking. The geological record provides ample evidence of microbial mediation in mound build-up and stabilisation, but as long as mound drilling is lacking, we have no opportunity to verify the role of such processes and identify the key actors in the earliest stage of onset and development of modern mounds. Some evidence from the past record and from present very-high resolution observations in the shallow seabed suggest an initial control by fluid venting, and fluid migration pathways have been imaged or are tentatively reconstructed by modelling in the concerned basins, but the ultimate link in the shallow subsurface seems still to elude a large part of our efforts. Surface sampling and analyses of both corals and surface sediments have largely failed in giving any conclusive evidence of present-day or recent venting in the considered basins. But on the other hand, applying rigourously the interpretational keys derived from e.g. Porcupine Seabight settings off NW Ireland on brand new prospective settings e.g. on the Moroccan margin have resulted in the discovery of totally new mound settings, in the middle of a field of giant, active mud volcanoes. Keys are apparently working, but we still do not

  8. A New Model for Gas Transfer and Storage in a Permeable Volcanic Edifice

    Science.gov (United States)

    Collinson, A. D.; Neuberg, J.

    2011-12-01

    There is a marked contrast between the behaviour of a volcano in an open system compared to one which is closed. It is therefore essential to understand degassing, to appreciate how much gas is lost and where. Previous studies by a variety of scientists have led to the accumulation of data via field evidence from both active and fossil volcanoes (Stasiuk et al., 1996), laboratory experiments (Moore et al., 1994) and conceptual modelling, in which Darcy's law has become increasingly applicable (Eichelberger et al., 1986; Edmonds et al., 2003). Of particular interest for this study, is the effect different permeabilities have on the degree and pattern of the gas flux. A new method has been devised to investigate gas transport and storage in a permeable volcanic edifice. The continuity equation and Darcy's law are amalgamated to derive a partial differential equation which is solved using a finite element method to obtain the gas pressure. The associated pressure gradient is then used within Darcy's law to calculate the gas flux. The properties of the gas are described by the ideal gas law. The strength of this method is that it allows the modelling of two and three dimensional structures both in stationary equilibrium and as a time dependent progression. A geometry is created and the pressure and permeabilites incorporated into the model as boundary and domain conditions respectively. The aim of the model is to investigate how variable permeability and pressure gradients influence the gas flux, for example highly permeable cracks in the dome, or impermeable layers within the volcanic structure. We also use this gas model to complement the model of Neuberg et al. (2006) in which brittle failure of the conduit-wall boundary is used as a trigger mechanism of low-frequency earthquakes. The associated behaviour of the gas in response to the brittle failure is simulated in our model by increasing the permeability through a narrow zone at the boundary between the conduit

  9. Reservoir characteristics and control factors of Carboniferous volcanic gas reservoirs in the Dixi area of Junggar Basin, China

    Directory of Open Access Journals (Sweden)

    Ji'an Shi

    2017-02-01

    Full Text Available Field outcrop observation, drilling core description, thin-section analysis, SEM analysis, and geochemistry, indicate that Dixi area of Carboniferous volcanic rock gas reservoir belongs to the volcanic rock oil reservoir of the authigenic gas reservoir. The source rocks make contact with volcanic rock reservoir directly or by fault, and having the characteristics of near source accumulation. The volcanic rock reservoir rocks mainly consist of acidic rhyolite and dacite, intermediate andesite, basic basalt and volcanic breccia: (1 Acidic rhyolite and dacite reservoirs are developed in the middle-lower part of the structure, have suffered strong denudation effect, and the secondary pores have formed in the weathering and tectonic burial stages, but primary pores are not developed within the early diagenesis stage. Average porosity is only at 8%, and the maximum porosity is at 13.5%, with oil and gas accumulation showing poor performance. (2 Intermediate andesite and basic basalt reservoirs are mainly distributed near the crater, which resembles the size of and suggests a volcanic eruption. Primary pores are formed in the early diagenetic stage, secondary pores developed in weathering and erosion transformation stage, and secondary fractures formed in the tectonic burial stage. The average porosity is at 9.2%, and the maximum porosity is at 21.9%: it is of the high-quality reservoir types in Dixi area. (3 The volcanic breccia reservoir has the same diagenetic features with sedimentary rocks, but also has the same mineral composition with volcanic rock; rigid components can keep the primary porosity without being affected by compaction during the burial process. At the same time, the brittleness of volcanic breccia reservoir makes it easily fracture under the stress; internal fracture was developmental. Volcanic breccia developed in the structural high part and suffered a long-term leaching effect. The original pore-fracture combination also made

  10. The small mounds of Bayuda region

    CERN Document Server

    Sparavigna, Amelia Carolina

    2010-01-01

    The Great Bend of the river Nile contains the Bayuda region with its volcanic core. Along the river, a fertile strip of land has attracting human settlement for thousands of years and is then rich of archaeological sites. The distribution of the sites near the Nile can be detected using Google Maps imagery. We can see many area covered by small mounds, probably burial sites. Some of the archaeological places are currently under the water of the Merowe Dam. With the satellite imagery, we have a portrait of the area close the dam before the closing of its gates.

  11. Diurnal respiration of a termite mound

    Science.gov (United States)

    King, Hunter; Ocko, Samuel; Mahadevan, L.

    2014-11-01

    Many species of fungus-harvesting termites build largely empty, massive mound structures which protrude from the ground above their subterranean nests. It has been long proposed that the function of these mounds is to facilitate exchange of heat, humidity, and respiratory gases; this would give the colony a controlled climate in which to raise fungus and brood. However, the specific mechanism by which the mound achieves ventilation has remained a topic of debate, as direct measurement of internal air flows has remained difficult. By directly measuring these elusive, tiny flows with a custom sensor, we find that the mound architecture of the species Odontotermes obesus takes advantage of daily oscillations in ambient temperature to drive convection and gas transport. This contradicts previous theories, which point to internal metabolic heating and external wind as driving forces. Our result, a novel example of deriving useful work from a fluctuating scalar parameter, should contribute to better understanding insect swarm construction and possible development in passive human architecture, both of which have been spurred by previous research on termites. We acknowledge support from HFSP.

  12. Mound facility physical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Tonne, W.R.; Alexander, B.M.; Cage, M.R.; Hase, E.H.; Schmidt, M.J.; Schneider, J.E.; Slusher, W.; Todd, J.E.

    1993-12-01

    The purpose of this report is to provide a baseline physical characterization of Mound`s facilities as of September 1993. The baseline characterizations are to be used in the development of long-term future use strategy development for the Mound site. This document describes the current missions and alternative future use scenarios for each building. Current mission descriptions cover facility capabilities, physical resources required to support operations, current safety envelope and current status of facilities. Future use scenarios identify potential alternative future uses, facility modifications required for likely use, facility modifications of other uses, changes to safety envelope for the likely use, cleanup criteria for each future use scenario, and disposition of surplus equipment. This Introductory Chapter includes an Executive Summary that contains narrative on the Functional Unit Material Condition, Current Facility Status, Listing of Buildings, Space Plans, Summary of Maintenance Program and Repair Backlog, Environmental Restoration, and Decontamination and Decommissioning Programs. Under Section B, Site Description, is a brief listing of the Site PS Development, as well as Current Utility Sources. Section C contains Site Assumptions. A Maintenance Program Overview, as well as Current Deficiencies, is contained within the Maintenance Program Chapter.

  13. Volcanic tremors and magma wagging: gas flux interactions and forcing mechanism

    Science.gov (United States)

    Bercovici, David; Jellinek, A. Mark; Michaut, Chloé; Roman, Diana C.; Morse, Robert

    2013-11-01

    Volcanic tremor is an important precursor to explosive eruptions and is ubiquitous across most silicic volcanic systems. Oscillations can persist for days and occur in a remarkably narrow frequency band (i.e. 0.5-7 Hz). The recently proposed magma-wagging model of Jellinek & Bercovici provides a basic explanation for the emergence and frequency evolution of tremor that is consistent with observations of many active silicic and andesitic volcanic systems. This model builds on work suggesting that the magma column rising in the volcanic conduit is surrounded by a permeable vesicular annulus of sheared bubbles. The magma-wagging model stipulates that the magma column rattles within the spring like foam of the annulus, and predicts oscillations at the range of observed tremor frequencies for a wide variety of volcanic environments. However, the viscous resistance of the magma column attenuates the oscillations and thus a forcing mechanism is required. Here we provide further development of the magma-wagging model and demonstrate that it implicitly has the requisite forcing to excite wagging behaviour. In particular, the extended model allows for gas flux through the annulus, which interacts with the wagging displacements and induces a Bernoulli effect that amplifies the oscillations. This effect leads to an instability involving growing oscillations at the lower end of the tremor frequency spectrum, and that drives the system against viscous damping of the wagging magma column. The fully non-linear model displays tremor oscillations associated with pulses in gas flux, analogous to observations of audible `chugging'. These oscillations also occur in clusters or envelopes that are consistent with observations of sporadic tremor envelopes. The wagging model further accurately predicts that seismic signals on opposite sides of a volcano are out of phase by approximately half a wagging or tremor period. Finally, peaks in gas flux occur at the end of the growing instability

  14. Experiments on gas-ash separation processes in volcanic umbrella plumes

    Science.gov (United States)

    Holasek, Rick E.; Woods, Andrew W.; Self, Stephen

    1996-03-01

    We present a series of analogue laboratory experiments which simulate the separation of ash and gas and the formation of secondary intrusions from finite volcanic umbrella plumes. We examined the lateral spreading of mixtures of freshwater and particles released into a laboratory tank containing a uniformly stratified aqueous solution. For times smaller than the sedimentation time of particles through the intrusion, the current remains coherent and intrudes laterally. As some of the particles settle into the underlying ambient fluid, a layer of particle-depleted fluid develops below the upper surface of the current and the density of the residual fluid is reduced. Over longer times, the intrusion ceases to be coherent, with small fingers of relatively buoyant, particle-depleted fluid rising from the upper part of the intrusion into the overlying fluid. Meanwhile, the lateral motion of the injected solution induces a return flow in the ambient fluid which sweeps some of the particles sedimenting from the lower surface of the intrusion inwards. As a result, relatively dense particle-laden fluid collects below the intrusion and then sinks into the underlying fluid. Eventually this fluid reaches a new neutral buoyancy height, where it intrudes to form a second laterally spreading current below the original intrusion. The process then repeats to form further weaker intrusions below. These results of the separation of the ash and volcanic gas in an umbrella plume are consistent with field observations at Sakurajima volcano where positively charged plumes, thought to consist of volcanic gas, have been observed above negatively charged plumes of ash. This work also suggests that volcanic aerosols may form up to a kilometer above the original injection height of the ash. In a strong wind shear, this could result in very different trajectories of the ash and gas and so be important for evaluating the impact of ash plumes on both aviation safety and volcanic aerosol formation

  15. Ground-based and airborne measurements of volcanic gas emissions at White Island in New Zealand

    Science.gov (United States)

    Tirpitz, Jan-Lukas; Poehler, Denis; Bobrowski, Nicole; Christenson, Bruce; Platt, Ulrich

    2017-04-01

    Quantitative understanding of volcanic gas emissions has twofold relevance for nature and society: 1) Variation in gas emission and/or in emitted gas ratios are tracers of the dynamic processes in the volcano interior indicating its activity. 2) Volcanic degassing plays an important role for the Earth's climate, for local sometimes even regional air quality and atmospheric chemistry. In autumn 2015, a campaign to White Island Volcano in New Zealand was organized to perform ground-based as well as airborne in-situ and remote sensing gas measurements of sulfur dioxide (SO2), carbon dioxide (CO2) and bromine monoxide (BrO). For all three gases the ratios and total emission rates were determined in different plume types and ages. An overview over the data will be presented with focus on the two most notable outcomes: 1) The first determination of the BrO/SO2 ratio in the White Island plume and a minimum estimate of the volcano's bromine emission rate; two of many parameters, which are important to assess the impact of volcanic degassing on the atmospheric halogen chemistry. 2) In-situ SO2 data was very successfully recorded with the PITSA, a prototype of a portable and cost-effective optical instrument. It is based on the principle of non-dispersive UV absorption spectroscopy and features different advantages over the customary electrochemical sensors, including a sub second response time, negligible cross sensitivities to other gases, and inherent calibration. The campaign data demonstrates the capabilities and limitations of the PITSA and shows, that it can be well applied as substitute for conventional electrochemical systems.

  16. Carbon and Noble Gas Isotopes in the Tengchong Volcanic Geothermal Area, Yunnan, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    XU Sheng; Shun'ich NAKAI; Hiroshi WAKITA; WANG Xianbin

    2004-01-01

    Carbon and noble gas isotope analyses are reported for bubbling gas samples from the Tengchong volcanic geothermal area near the Indo-Eurasian suture zone. All samples contain a resolvable component of mantle-derived 3He.Occurrence of mantle-derived 3He coincides with surface volcanism. However, 3He occurs over a larger geographic area than do surface volcanics. δ13C values for CO2 and CH4 vary from -33.4 ‰ to 1.6 ‰ and from -52.8 ‰ to -2.8 ‰,respectively. He and C isotope systematics indicate that CO2 and CH4 in the CO2-rich gases originated predominantly from magmatic component mixed with crustal CO2 produced from carbonate. However, breakdown of organic matter and nearsurface processes accounts for the CH4 and CO2 in N2-rich gases. 3He/4He ratio distribution pattern suggests that mantlederived He and heat sources of high-temperature system in central Tengchong originate from a hidden magma reservoir at subsurface. CO2-rich gases with the highest 3He/4He ratio (5.2 Ra) may be representative of the Tengchong magmatic component. Compared with MORB, this relative low 3He/4He ratio could be fully attributed to either deep crustal contamination, or radioactive aging, or past contamination of the local mantle by U- and Th-rich subducted crustal material.However, a combination of low 3He/4He, high radiogenic 4He/40Ar ratio and identical CO2/3He and δ13Cco2 relative to MORB may suggest addition of prior subductedd crsustal material (ca 1%-2%) to the MORB reservoir around 1.3 Ga ago,which is essentially compatible with the LIL-elements, and Sr-Nd-Pb isotopes of volcanic rocks.

  17. Volcanic gas measurements at Mount Cleveland, 14-15 August 2015

    Science.gov (United States)

    Werner, Cynthia A.; Kern, Christoph; Kelly, Peter

    2017-01-01

    On 14-15 August 2015, helicopter-based measurements were made of the volcanic gases emitted from Mount Cleveland, AK. An upward-looking differential optical absorption spectroscopy (DOAS) system was used to measure incident scattered solar ultraviolet radiation while traversing beneath the plume on multiple occasions 14-15 August. This data was used to derive SO2 emission rates. Additionally, a Multi-Component Gas Analyzer System (Multi-GAS) was used to make measurements of trace gas concentrations while on a dedicated measurement flight passing through the gas plume on 15 August (19:15 - 19:56 UTC). Radiance spectra and gas compositions were both recorded at 1 second time resolution. Each spectrum and gas measurement was stamped with the GPS time and location. Each spectrum was saved in a separate ASCII file which includes 2048 radiances measured in the 285 - 430 nm spectral region and metadata associated with each acquisition. The Multi-GAS measurements are saved in a spreadsheet in the *.csv format.

  18. Vapour transport of rare earth elements (REE) in volcanic gas: Evidence from encrustations at Oldoinyo Lengai

    Science.gov (United States)

    Gilbert, C. D.; Williams-Jones, A. E.

    2008-10-01

    Fumarolic encrustations and natrocarbonatite lava from the active crater of Oldoinyo Lengai volcano, Tanzania, were sampled and analysed. Two types of encrustation were distinguished on the basis of their REE content, enriched (~ 2800-5600 × [REE chondrite]) and depleted (~ 100-200 × [REE chondrite]) relative to natrocarbonatite (1700-1900 × [REE chondrite]. REE-enriched encrustations line the walls of actively degassing fumaroles, whereas REE-depleted encrustations occur mainly along cracks in and as crusts on cooling natrocarbonatite lava flows; one of the low REE encrustation samples was a stalactite from the wall of a possible fumarole. The encrustations are interpreted to have different origins, the former precipitating from volcanic gas and the latter from meteoric/ground water converted to steam by the heat of the overlying lava flow(s). REE-profiles of encrustations and natrocarbonatite are parallel, suggesting that there was no preferential mobilization of specific REE by either volcanic vapour or meteoric water vapour. The elevated REE-content of the first group of encrustations suggests that direct REE-transport from natrocarbonatite to volcanic vapour is possible. The REE trends observed in samples precipitating directly from the volcanic vapour cannot be explained by dry volatility based on the available data as there is no evidence in the encrustation compositions of the greatly enhanced volatility predicted for Yb and Eu. The observed extreme REE-fractionation with steep La/Sm slopes parallel to those of the natrocarbonatite reflects solvation and complexation reactions in the vapour phase that did not discriminate amongst the different REE or similar transport of REE in both the natrocarbonatite magma and its exsolving vapour. The low concentrations of REE in the encrustations produced by meteoric vapour suggest that the temperature was too low or that this vapour did not contain the ligands necessary to permit significant mobilization of the REE.

  19. Experimental study of jet gas-particle interaction generated during explosive volcanic eruptions

    Science.gov (United States)

    Medici, E. F.; Waite, G. P.

    2014-12-01

    During violent volcanic eruptions, a shock wave may be generated that is immediately followed by the formation of a supersonic jet. The overpressurized vapor-solid-liquid mixture being ejected begins to expand and accelerate. Oblique shock waves and rarefaction waves are generated at the edge of the crater. The oblique shock waves, inclined relatively to the flow axis, intersect forming a structure called a "Mach disk" or "Mach diamond". This pattern repeats until the jet decelerates into subsonic flow. In an explosive volcanic eruption, unlike other applications involving jets, a mixture of hot gas and solid particles is present. The mixture typically contains a relatively high percentage of solid particles of different sizes. The relationship between jet and particle is one the major parameters affecting the formation of ash plume dynamics and the pyroclastic flows. Therefore, a more comprehensive study is needed in order to understand the mixing occurring within the volcanic eruption jet, specifically, the effect of particle size and concentration. In this work, a series of analog explosive volcanic experiments using an atmospheric shock tube are performed to generate supersonic jets. High-speed video imaging of the expanding jet as well as the pressure evolution at different points in space are recorded for different values of initial energy and particle sizes and concentrations. Particles of different sizes and in various concentrations are placed inside the jet stream in which all the environmental conditions are monitored. Understanding of the coupling between the particles and the jet dynamics interaction is the first step toward a more thorough understanding of ash plume dynamics and the pyroclastic flows formation.

  20. Analysis of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Mettam, J.D.; Allsop, N.W.H.; Bonafous, P.

    Working Group 12 was set up to consider the analysis of rubble mound breakwaters with a view to achieving a better understanding of safety aspects. The working group decided to develop the practical application of risk analysis in the design of rubble mound breakwaters by using partial coefficien...

  1. Permeability of Rubble Mound Material

    DEFF Research Database (Denmark)

    Williams, A.F.; Burcharth, H. F.; Adel, H. den;

    The flow of water through the pores of rubble mound breakwaters has two effects upon breakwater performance. The pore pressures generated within the rubble material will effect the stability of the mound. The flow of water in and out of the pores plays a critical part in the dissipation of wave e...

  2. Termite mounds harness diurnal temperature oscillations for ventilation.

    Science.gov (United States)

    King, Hunter; Ocko, Samuel; Mahadevan, L

    2015-09-15

    Many species of millimetric fungus-harvesting termites collectively build uninhabited, massive mound structures enclosing a network of broad tunnels that protrude from the ground meters above their subterranean nests. It is widely accepted that the purpose of these mounds is to give the colony a controlled microclimate in which to raise fungus and brood by managing heat, humidity, and respiratory gas exchange. Although different hypotheses such as steady and fluctuating external wind and internal metabolic heating have been proposed for ventilating the mound, the absence of direct in situ measurement of internal air flows has precluded a definitive mechanism for this critical physiological function. By measuring diurnal variations in flow through the surface conduits of the mounds of the species Odontotermes obesus, we show that a simple combination of geometry, heterogeneous thermal mass, and porosity allows the mounds to use diurnal ambient temperature oscillations for ventilation. In particular, the thin outer flutelike conduits heat up rapidly during the day relative to the deeper chimneys, pushing air up the flutes and down the chimney in a closed convection cell, with the converse situation at night. These cyclic flows in the mound flush out CO2 from the nest and ventilate the colony, in an unusual example of deriving useful work from thermal oscillations.

  3. Water and gas geochemistry of the Calatrava Volcanic Province (CVP) hydrothermal system (Ciudad Real, central Spain)

    Science.gov (United States)

    Vaselli, Orlando; Nisi, Barbara; Tassi, Franco; Giannini, Luciano; Grandia, Fidel; Darrah, Tom; Capecchiacci, Francesco; del Villar, Pèrez

    2013-04-01

    An extensive geochemical and isotopic investigation was carried out in the water and gas discharges of the Late Miocene-Quaternary Calatrava Volcanic Province (CVP) (Ciudad Real, Spain) with the aim reconstruct the fluid circulation in the area. CVP consists of a series of scattered (monogenetic) vents from where alkaline lava flows and pyroclastic deposits formed in two different periods. The first stage (8.7-6.4 Ma) mainly included ultra-potassic mafic extrusives, whilst the second stage (4.7-1.75 Ma) prevalently originated alkaline and ultra-alkaline volcanics. Both stages were followed by a volcanic activity that extended up to 1.3 and 0.7 Ma, respectively. This area can likely be regarded as one of the most important emitting zones of CO2 in the whole Peninsular Spain along with that of Selva-Emporda in northeastern Spain (Cataluña) and it can be assumed as one of the best examples of natural analogues of CO2 leakages in Spain. This latter aspect is further evidenced by the relatively common water-gas blast events that characterize the CCVF. In the last few years the presence of a CO2-pressurized reservoir at a relatively shallow level as indeed caused several small-sized explosion particularly during the drilling of domestic wells. The fluid discharging sites are apparently aligned along well-defined directions: NW-SE and NNW-SSE and subordinately, ENE-WSW, indicating a clear relationship between the thermal discharges and the volcanic centers that also distribute along these lineaments. The CVP waters are mostly hypothermal (up to 33 °C) and are generally Mg(Ca)-HCO3 in composition and occasionally show relatively high concentrations of Fe and Mn, with pH and electrical conductivity down to 5.5 and up to 6.5 mS/cm, respectively. The oxygen and hydrogen isotopes suggest a meteoric origin for these waters. The mantle source of these volcanic products is apparently preserved in the many CO2-rich (up to 990,000 mmol/mol) gas discharges that characterize CVP

  4. Mound Facility. 1978 annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1979-12-31

    For Mound Facility, the year 1978 was one of progress marked by enhanced mission assignments and significant milestones. The thirtieth anniversary of the site was celebrated, and Monsanto Research Corporation began a new 5 year contract to operate the Mound Facility. Long-standing production assignments were strengthened, and were were given a new responsibility: to develop and produce all ceramic parts used in Mound-build products. progress toward US energy objectives was bolstered by Mound programs supporting the development of nuclear fusion poser, unlocking previously us attainable fossil fuels, ensuring the safety and security of nuclear material handling operations, and exploring the real promise of energy form the sun. In 1978, we focused our attention on many efforts aimed at a brighter, more secure future.

  5. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs

    Science.gov (United States)

    Blundy, J.; Mavrogenes, J.; Tattitch, B.; Sparks, S.; Gilmer, A.

    2015-03-01

    Porphyry copper deposits, that is, copper ore associated with hydrothermal fluids rising from a magma chamber, supply 75% of the world's copper. They are typically associated with intrusions of magma in the crust above subduction zones, indicating a primary role for magmatism in driving mineralization. However, it is not clear that a single, copper-rich magmatic fluid could trigger both copper enrichment and the subsequent precipitation of sulphide ore minerals within a zone of hydrothermally altered rock. Here we draw on observations of modern subduction zone volcanism to propose an alternative process for porphyry copper formation. We suggest that copper enrichment initially involves metalliferous, magmatic hyper-saline liquids, or brines, that exsolve from large, magmatic intrusions assembled in the shallow crust over tens to hundreds of thousands of years. In a subsequent step, sulphide ore precipitation is triggered by the interaction of the accumulated brines with sulphur-rich gases, liberated in short-lived bursts from the underlying mafic magmas. We use high-temperature and high-pressure laboratory experiments to simulate such gas-brine interactions. The experiments yield copper-iron sulphide minerals and hydrogen chloride gas at magmatic temperatures of 700-800 °C, with textural and chemical characteristics that resemble those in porphyry copper deposits. We therefore conclude that porphyry copper ore forms in a two-stage process of brine enrichment followed by gas-induced precipitation.

  6. Rubble Mound Breakwater Failure Modes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Z., Liu

    1995-01-01

    The RMBFM-Project (Rubble Mound Breakwater Failure Modes) is sponsored by the Directorate General XII of the Commission of the European Communities under the Contract MAS-CT92- 0042, with the objective of contributing to the development of rational methods for the design of rubble mound breakwaters...... modes, plus development of related partial coefficients which make it possible to design according to preselected reliability levels. Due to limited space only the major activities are described....

  7. Generation of porphyry copper deposits by gas-brine reaction in volcanic arcs

    Science.gov (United States)

    Blundy, Jon; Mavrogenes, John; Tattitch, Brian; Sparks, Steve; Gilmer, Amy

    2014-05-01

    Porphyry copper deposits (PCDs) are characterised by a close spatial and temporal association with small, hypabyssal intrusions of silicic magmas in volcanic arcs. PCD formation requires elevated chlorine and water to concentrate copper in magmatic hypersaline liquids (or brines), and elevated sulphur to precipitate copper-rich sulphides. These twin requirements are hard to reconcile with experimental and petrological evidence that voluminous chlorine-rich, hydrous silicic magmas, of the variety favourable to copper enrichment, lack sufficient sulphur to precipitate directly the requisite quantities of sulphides. These features are, however, consistent with observations of active volcanic arcs whereby PCDs can be viewed as roots of dome volcanoes above shallow reservoirs where silicic magmas accumulate over long time spans. During protracted periods of dormancy metal-enriched dense brines accumulate in and above the silicic reservoir through slow, low-pressure degassing. Meanwhile cogenetic volatile-rich mafic magmas and their exsolved, sulphur and CO2-rich fluids accumulate in deeper reservoirs. Periodic destabilisation of these reservoirs leads to short-lived bursts of volcanism liberating sulphurous gases, which react with the shallow-stored brines to form copper-rich sulphides and acidic vapours. We test this hypothesis with a novel set of 'porphyry in a capsule' experiments designed to simulate low-pressure (1-2 kbar) interaction of basalt-derived, sulphur-rich gases with brine-saturated, copper-bearing, but sulphur-free, granite. Experiments were run at 720-850 ° C in cold-seal apparatus with basaltic andesite, loaded with H2O and S, situated below dacite, loaded with H2O, Cl and Cu. At run conditions both compositions are substantially degassed and crystallized. S-rich gas from the basaltic andesite ascends to react with Cu-rich brines exsolved from the dacite, Our experiments reveal the direct precipitation of copper-sulphide minerals, in vugs and veins

  8. Characteristics of volcanic gas correlated to the eruption activity; Case study in the Merapi Volcano, periods of 1990-1994

    Directory of Open Access Journals (Sweden)

    Priatna Priatna

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol2no4.20074Volcanic gases, collected from Gendol and Woro solfatara fields, the summit of Merapi Volcano during 1990-1994, show an increase in chemical composition of H , CO, CO , SO , and HCl prior to the volcanic events, on the contrary to the drastic decreasing water vapour. The carbon/sulfur ratio of the volcanic gases lies between 1.5 and 5.7 which means that they were derived from the fresh magma. The Apparent Equilibrium Temperature (AET which is calculated from chemical compositions of volcanic gases using reaction of SO +3H = H S+2H O showed an increasing value prior to the volcanic events. The Merapi activities lasted during August 1990 to November 1994 showed a significant increase in ratio SO /H S prior to the November 1994 pyroclastic flow. The isotopic composition of volcanic gas condensates indicates that water vapour in Gendol is directly derived from the fresh magma. On the other hand, the contamination and cooling by the subsurface water occurred around the Woro field at a shallow part. 

  9. Aviation response to a widely dispersed volcanic ash and gas cloud from the August 2008 eruption of Kasatochi, Alaska, USA

    Science.gov (United States)

    Guffanti, Marianne; Schneider, David J.; Wallace, Kristi L.; Hall, Tony; Bensimon, Dov R.; Salinas, Leonard J.

    2010-01-01

    The extensive volcanic cloud from Kasatochi's 2008 eruption caused widespread disruptions to aviation operations along Pacific oceanic, Canadian, and U.S. air routes. Based on aviation hazard warnings issued by the National Oceanic and Atmospheric Administration, U.S. Geological Survey, the Federal Aviation Administration, and Meteorological Service of Canada, air carriers largely avoided the volcanic cloud over a 5 day period by route modifications and flight cancellations. Comparison of time coincident GOES thermal infrared (TIR) data for ash detection with Ozone Monitoring Instrument (OMI) ultraviolet data for SO2 detection shows congruent areas of ash and gas in the volcanic cloud in the 2 days following onset of ash production. After about 2.5 days, the area of SO2 detected by OMI was more extensive than the area of ash indicated by TIR data, indicating significant ash depletion by fall out had occurred. Pilot reports of visible haze at cruise altitudes over Canada and the northern United States suggested that SO2 gas had converted to sulfate aerosols. Uncertain about the hazard potential of the aging cloud, airlines coped by flying over, under, or around the observed haze layer. Samples from a nondamaging aircraft encounter with Kasatochi's nearly 3 day old cloud contained volcanic silicate particles, confirming that some fine ash is present in predominantly gas clouds. The aircraft's exposure to ash was insufficient to cause engine damage; however, slightly damaging encounters with volcanic clouds from eruptions of Reventador in 2002 and Hekla in 2000 indicate the possibility of lingering hazards associated with old and/or diffuse volcanic clouds.

  10. Insights from fumarole gas geochemistry on the recent volcanic unrest of Pico do Fogo, Cape Verde

    Science.gov (United States)

    Melián, Gladys V.; Dionis, Samara; Asensio-Ramos, María; Padilla, Germán; Fernandes, Paulo; Pérez, Nemesio M.; Sumino, Hirochika; Padrón, Eleazar; Hernández, Pedro A.; Silva, Sónia; Pereira, José Manuel; Semedo, Helio; Cabral, Jeremias

    2015-04-01

    Fogo is a volcanic island of the Cape Verde archipelago and host at its center the active stratovolcano Pico do Fogo (2829 m.a.s.l.). On November 23, 2014 a new volcanic eruption started at the southwestern flank of Pico do Fogo, after 19 years of the last eruptive event. Since 2007, regular sampling and analysis of fumarole gas discharges from a fumarole (F1) has been performed in a yearly basis to monitor the chemical and isotopic gas composition. From 2008, fumarole gas sampling was also performed in a second fumarole (F2). During the period of study, outlet temperature in F1 has ranged between 62 to 159°C, whereas the F2 has ranged between 295 and 344°C. For determination of major gas species, fumarolic gases were collected in evacuated flasks containing a 5N NaOH solution. In addition, condensed steam and non-condensable gases (dry gas) were sampled by flowing the fumarolic gases through a water-cooled condenser. The isotopic composition of He (3He/4He) was determined on dry gas samples at the GRC of Tokyo University. Water vapor is by far the most abundant component, as shown by a gas/steam molar ratio between 0.08 and 0.48, followed by CO2 (384,606 - 988,679 mmol/mol in the dry gas phase). The concentration of the other gases in the gas dry phase and expressed in mol/mol: Stotal varies from 3,411 to 606,054, N2 from 835 to 84,672, H2 from 45.6 to 68,439, CH4 from 0 to 61,785, Cl from 4.9 to 1,729, CO from 0 to 1,396 and He from 4.4 to 617. The presence of O2 in concentrations from 10.4 to 17,350 mol/mol reflects minor air contamination either during sampling or storage, or naturally in the sampled vents. Carbon isotopic composition of Pico do Fogo fumarolic CO2, expressed in d13C-CO2 vs. VPDB notation, varied from -4.62 to -4.06 ‰, whereas 3He/4He data, expressed as R/RA, ranged from 5.70 to 8.81. In the classical He-Ar-N2 triangular diagram, most of samples plot between the He, air and ASW end members, showing compositions variably contaminated by

  11. Numerical investigation of gas-particle interaction in polydisperse volcanic jets

    Science.gov (United States)

    Carcano, Susanna; Esposti Ongaro, Tomaso; Bonaventura, Luca; Neri, Augusto

    2014-05-01

    We investigate the problem of underexpanded jet decompression when the injected fluid is a mixture of a gaseous phase and different classes of solid particles. The underexpanded multiphase jet problem is representative of phenomena that can be observed in the first stages of explosive volcanic eruptions. Whereas the case of homogeneous jets has been studied deeply in the literature, both experimentally, theoretically and numerically, the case of multiphase gas--particle jets still presents some open issues. It has been proven theoretically and experimentally that vents with supersonic or sonic velocity and gas pressure greater than the atmospheric one result in a rapid expansion and acceleration of the fluid to high Mach number. A series of expansion waves form and are reflected as compression waves at the flow boundary. The compression waves coealesce to form a standing normal shock wave (Mach disk), across which the fluid is rapidly compressed and decelerated to subsonic speeds. When solid particles are added to the gas flow, new phenomena associated to kinetic and thermal non-equilibrium between gas and particulate phases arise. Such effects are controlled by drag and heat exchange terms in the momentum and energy equations. In the present work we carry out two- and three-dimensional numerical simulations with the multiphase flow model PDAC (Neri et al., J. Geophys. Res, 2003; Carcano et al., Geosci. Mod. Dev., 2013), to identify and quantify non-equilibrium effects related to the interaction between the jet decompression structure and solid particles. We quantify, on a theoretical basis, the expected non-equilibrium effects between the gas and the solid phase in terms of the particle Stokes numer (St), i.e. the ratio between the particle relaxation time and a characteristic time scale of the jet (taken as the formation time of the Mach disk shock), for two sample grain-size distributions of natural events (Mount St. Helens, 1980; Vesuvius, aD 79). The Stokes

  12. Intercomparison of SO2 camera systems for imaging volcanic gas plumes

    Science.gov (United States)

    Kern, Christoph; Lübcke, Peter; Bobrowski, Nicole; Campion, Robin; Mori, Toshiya; Smekens, Jean-François; Stebel, Kerstin; Tamburello, Giancarlo; Burton, Mike; Platt, Ulrich; Prata, Fred

    2015-07-01

    SO2 camera systems are increasingly being used to image volcanic gas plumes. The ability to derive SO2 emission rates directly from the acquired imagery at high time resolution allows volcanic process studies that incorporate other high time-resolution datasets. Though the general principles behind the SO2 camera have remained the same for a number of years, recent advances in CCD technology and an improved understanding of the physics behind the measurements have driven a continuous evolution of the camera systems. Here we present an intercomparison of seven different SO2 cameras. In the first part of the experiment, the various technical designs are compared and the advantages and drawbacks of individual design options are considered. Though the ideal design was found to be dependent on the specific application, a number of general recommendations are made. Next, a time series of images recorded by all instruments at Stromboli Volcano (Italy) is compared. All instruments were easily able to capture SO2 clouds emitted from the summit vents. Quantitative comparison of the SO2 load in an individual cloud yielded an intra-instrument precision of about 12%. From the imagery, emission rates were then derived according to each group's standard retrieval process. A daily average SO2 emission rate of 61 ± 10 t/d was calculated. Due to differences in spatial integration methods and plume velocity determination, the time-dependent progression of SO2 emissions varied significantly among the individual systems. However, integration over distinct degassing events yielded comparable SO2 masses. Based on the intercomparison data, we find an approximate 1-sigma precision of 20% for the emission rates derived from the various SO2 cameras. Though it may still be improved in the future, this is currently within the typical accuracy of the measurement and is considered sufficient for most applications.

  13. Intercomparison of SO2 camera systems for imaging volcanic gas plumes

    Science.gov (United States)

    Kern, Christoph; Lübcke, Peter; Bobrowski, Nicole; Campion, Robin; Mori, Toshiya; Smekens, Jean-Francois; Stebel, Kerstin; Tamburello, Giancarlo; Burton, Mike; Platt, Ulrich; Prata, Fred

    2015-01-01

    SO2 camera systems are increasingly being used to image volcanic gas plumes. The ability to derive SO2 emission rates directly from the acquired imagery at high time resolution allows volcanic process studies that incorporate other high time-resolution datasets. Though the general principles behind the SO2 camera have remained the same for a number of years, recent advances in CCD technology and an improved understanding of the physics behind the measurements have driven a continuous evolution of the camera systems. Here we present an intercomparison of seven different SO2 cameras. In the first part of the experiment, the various technical designs are compared and the advantages and drawbacks of individual design options are considered. Though the ideal design was found to be dependent on the specific application, a number of general recommendations are made. Next, a time series of images recorded by all instruments at Stromboli Volcano (Italy) is compared. All instruments were easily able to capture SO2 clouds emitted from the summit vents. Quantitative comparison of the SO2 load in an individual cloud yielded an intra-instrument precision of about 12%. From the imagery, emission rates were then derived according to each group's standard retrieval process. A daily average SO2 emission rate of 61 ± 10 t/d was calculated. Due to differences in spatial integration methods and plume velocity determination, the time-dependent progression of SO2 emissions varied significantly among the individual systems. However, integration over distinct degassing events yielded comparable SO2 masses. Based on the intercomparison data, we find an approximate 1-sigma precision of 20% for the emission rates derived from the various SO2 cameras. Though it may still be improved in the future, this is currently within the typical accuracy of the measurement and is considered sufficient for most applications.

  14. Geochemistry of volcanic gas at the 2012-13 New Tolbachik eruption, Kamchatka

    Science.gov (United States)

    Chaplygin, I. V.; Lavrushin, V. Y.; Dubinina, E. O.; Bychkova, Y. V.; Inguaggiato, S.; Yudovskaya, M. A.

    2016-09-01

    We report measurements of the chemical and isotopic composition of gas emitted from the lava flow at the 2012-13 New Tolbachik eruption. Gas and condensate samples were taken from two vents over a lava tube in May 2013. The 1030 °C gas sample was collected in evacuated Giggenbach bottle from a periodically pumping-to-venting outlet above active lava flow ~ 300 m from Naboko cone. Concentrations of major components in the 1030 °C gas sample are (mol%): 95.5 H2O, 0.47 CO2, 2.01 SO2, 1.18 HCl, 0.34 HF that are within a range of gas compositions for subduction zone volcanoes. Isotopic analysis of He gives a corrected to atmosphere R/Ra ratio = 7.24 (He/Ne ratio = 1.41) that is close to MORB values. The 1030 °C condensate contained 9.7 ppm Cu, 2.5 ppm Zn, 1.5 ppm Tl, 20 ppb Re and 3 ppb Au, and can be considered as a representative sample for the metal composition of exsolved magmatic gases at the 2012-13 Tolbachik eruption. Isotopic data on the 1030 °C condensate (δ18O = 6.4‰, δD = - 32‰) indicate a magmatic source. Another condensate sample taken at 690 °C was found to be drastically different from the magmatic 1030 °C condensate. We suggest that the disproportional enrichment in trace elements of this 690 °C condensate as compared to the 1030 °C condensate could result from evaporation at forced pumping during sampling and possible dissolution of earlier precipitated sublimates in the gas conduit. Unusual isotopic composition of the 690 °C condensate (δ18O = 18.9‰, δD = - 68.5‰) can be explained by the isotopic exchange between volcanic vapor and atmospheric O2 (δ18O = 23.5‰).

  15. Measurements of the gas emission from Holuhraun volcanic fissure eruption on Iceland, using Scanning DOAS instruments

    Science.gov (United States)

    Galle, Bo; Pfeffer, Melissa; Arellano, Santiago; Bergsson, Baldur; Conde, Vladimir; Barsotti, Sara; Stefansdottir, Gerdur; Ingvarsson, Thorgils; Bergsson, Bergur; Weber, Konradin

    2016-04-01

    On 31 August 2014 a volcanic fissure eruption started at Holuhraun on Iceland. The eruption lasted for 6 months and was by far the strongest source of sulfur dioxide in Europe over the last 230 years, with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affected people within Iceland. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions was developed. Since the first day of the eruption several of these novel instruments were monitoring the SO2 emission from the eruption. A lot of work was needed to sustain this operation during the winter at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions has required the development of novel methods to derive reliable flux estimates. A simple approach to make a first order correction for atmospheric scattering has been applied, as well as filtering of the dataset to remove the data most affected by scattering. Substantial work has also been made to obtain realistic information on plume height and wind speed. The data from these instruments are the only sustained ground-based measurements of this important gas emission event. In this presentation we will discuss the instrumental issues and evaluation procedures and present the latest version of the emission estimates made from our measurements.

  16. Reservoir Potential of Silurian Carbonate Mud Mounds in the Southern Sichuan Basin, Central China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenzhi; YANG Xiaoping; Steve KERSHAW; ZHANG Baomin

    2006-01-01

    Lower Silurian mud mounds of the Shinuilan Formation, located in the southern Sichuan Basin, China, have developed in open shelf settings in deeper water than shallow-water reef-bearing limestones that occur in the region. An integration of the outcrop, drill data and seismic profiles show that contemporaneous faults have controlled the boundary and distribution of the sedimentary facies of Lower Silurian rocks in the southern Sichuan Basin. Mounds appear to have developed in the topographic lows formed by synsedimentary faulting, on the shelf of the Yangtze Platform. Average mound thickness is 20 m, maximum 35 m. Mounds are composed mainly of micrite, possibly microbially bound, and are overlain by shales. Mound tops are preferentially dolomitized, with the Mg2+ source probably from the clay content of the mound-top carbonate. Microfacies analysis and reconstruction of the diagenetic history reveal that the mound tops have higher porosity, and are gas targets; in contrast, mound cores and limbs show pores filled by three generations of calcite cement, and therefore have a low gas potential.

  17. Drought Impact on Fumarole Gas Composition at Lassen Volcanic National Park, CA.

    Science.gov (United States)

    Bergfeld, D.; Lewicki, J. L.; Hunt, A. G.

    2015-12-01

    Surface expressions of the hydrothermal system at Lassen Volcanic National Park include numerous solfataras to the south and southeast of Lassen Peak. Extensive sampling of gas for chemical and isotope analyses took place from the mid-1970s through 2000. Based on those data the model for the Lassen hydrothermal system suggests the main gas upflow occurs at Sulphur Works, which is part of a circulating hydrothermal flow cell (HC1) that includes Bumpass Hell and Little Hot Springs Valley (Janik & McLaren, 2010). A second, slightly cooler cell (HC2) provides gas and steam to Boiling Springs Lake, Devils Kitchen and ultimately to features at Terminal Geyser. As part of the USGS volcano monitoring effort, sampling of Lassen gases resumed in 2014. Gas compositions of boiling point and superheated fumaroles at four of the Lassen solfataras contained lower concentrations of meteoric-derived components than most early samples. In 2014 the combined N2 and Ar concentrations from the individual areas decreased on average by 50 to 65% relative to CO2. N2/Ar ratios also shifted away from the ratio in air-saturated water toward values as high as 171, consistent with a decline in meteoric water content. Concentrations of hydrothermal gases CO2, H2S, and CH4, and d13C-CO2 values are similar to the early data. Helium concentrations are variable and show no trends. Helium isotope ratios (Rc/RA) since 2007 from HC1 are between 6.9 and 7.5 and for HC2 are between 6.0 and 6.5. A 2014 Terminal Geyser sample had a value of 6.0. A longer record of helium isotope data is required to examine temporal trends. Water in the Lassen hydrothermal system is ultimately derived from rain and snowfall at higher elevations in the park. The area has experienced drought conditions since at least 2012. The 2014 dataset suggests that the drought may influence gas compositions by reducing the input of shallow meteoric water. Lassen gases from the California drought of 1976-1977 exhibit similar behavior.

  18. Aborted eruptions at Mt. Etna (Italy) in spring 2007 unveiled by an integrated study of gas emission and volcanic tremor

    Science.gov (United States)

    Falsaperla, S.; Behncke, B.; Giammanco, S.; Neri, M.; Langer, H.; Pecora, E.; Salerno, G.

    2012-04-01

    In spring 2007, a sequence of paroxysmal episodes took place at the Southeast Crater of Mt. Etna, Italy. Eruptive activity, characterised by Strombolian explosions, lava fountains, emission of lava flows and tephra, were all associated with an outstanding increase in the amplitude of volcanic tremor. In periods of quiescence between the eruptive episodes, recurring phases of seismic unrest were observed in forms of small temporary enhancements of the volcanic tremor amplitude, even though none of them culminated in eruptive activity. Here, we present the results of an integrated geophysical and geochemical data analysis encompassing records of volcanic tremor, thermal data, plume SO2 flux and radon over two months. We conclude that between February and April 2007, magma triggered repeated episodes of gas pulses and rock fracturing, but failed to reach the surface. Our multidisciplinary study allowed us to unveil these 'aborted' eruptions by investigating the long-temporal evolution of gas measurements along with seismic radiation. Short-term changes were additionally highlighted using a method of pattern classification based on Kohonen Maps and Fuzzy Clustering applied to volcanic tremor and radon data.

  19. Impact of diagenesis on carbonate mound formation

    NARCIS (Netherlands)

    van der Land, C.

    2011-01-01

    This thesis is devoted to define the parameters influencing cold-water coral growth and therefore carbonate mound development with a focus on the impact of diagenesis on mound sediments. The first part of this thesis (Chapters 2 to 4) discusses the distributionand growth history of carbonate mounds,

  20. Volcanic gas composition changes during the gradual decrease of the gigantic degassing activity of Miyakejima volcano, Japan, 2000-2015

    Science.gov (United States)

    Shinohara, Hiroshi; Geshi, Nobuo; Matsushima, Nobuo; Saito, Genji; Kazahaya, Ryunosuke

    2017-02-01

    The composition of volcanic gases discharged from Miyakejima volcano has been monitored during the intensive degassing activity that began after the eruption in 2000. During the 15 years from 2000 to 2015, Miyakejima volcano discharged 25.5 Mt of SO2, which required degassing of 3 km3 of basaltic magma. The SO2 emission rate peaked at 50 kt/day at the end of 2000 and quickly decreased to 5 kt/day by 2003. During the early degassing period, the volcanic gas composition was constant with the CO2/SO2 = 0.8 (mol ratio), H2O/SO2 = 35, HCl/SO2 = 0.08, and SO2/H2S = 15. The SO2 emission rate decreased gradually to 0.5 kt/day by 2012, and the gas composition also changed gradually to CO2/SO2 = 1.5, H2O/SO2 = 150, HCl/SO2 = 0.15, and SO2/H2S = 6. The compositional changes are not likely caused by changes in degassing pressure or volatile heterogeneity of a magma chamber but are likely attributed to an increase of hydrothermal scrubbing caused by large decrease of the volcanic gas emission rate, suggesting a supply of gases with constant composition during the 15 years. The intensive degassing was modeled based on degassing of a convecting magma conduit. The gradual SO2 emission rate that decrease without changes in volcanic gas composition is attributed to a reduction of diameter of the convecting magma conduit.

  1. A photographic and acoustic transect across two deep-water seafloor mounds, Mississippi Canyon, northern Gulf of Mexico

    Science.gov (United States)

    Hart, P.E.; Hutchinson, D.R.; Gardner, J.; Carney, R.S.; Fornari, D.

    2008-01-01

    In the northern Gulf of Mexico, a series of seafloor mounds lie along the floor of the Mississippi Canyon in Atwater Valley lease blocks 13 and 14. The mounds, one of which was drilled by the Chevron Joint Industry Project on Methane Hydrates in 2005, are interpreted to be vent-related features that may contain significant accumulations of gas hydrate adjacent to gas and fluid migration pathways. The mounds are located ???150 km south of Louisiana at ???1300 m water depth. New side-scan sonar data, multibeam bathymetry, and near-bottom photography along a 4 km northwest-southeast transect crossing two of the mounds (labeled D and F) reveal the mounds' detailed morphology and surficial characteristics. Mound D, ???250 m in diameter and 7-10 m in height, has exposures of authigenic carbonates and appears to result from a seafloor vent of slow-to-moderate flux. Mound F, which is ???400 m in diameter and 10-15 m high, is covered on its southwest flank by extruded mud flows, a characteristic associated with moderate-to-rapid flux. Chemosynthetic communities visible on the bottom photographs are restricted to bacterial mats on both mounds and mussels at Mound D. No indications of surficial gas hydrates are evident on the bottom photographs.

  2. Are termite mounds biofilters for methane? - Challenges and new approaches to quantify methane oxidation in termite mounds

    Science.gov (United States)

    Nauer, Philipp A.; Hutley, Lindsay B.; Bristow, Mila; Arndt, Stefan K.

    2015-04-01

    Methane emissions from termites contribute around 3% to global methane in the atmosphere, although the total source estimate for termites is the most uncertain among all sources. In tropical regions, the relative source contribution of termites can be far higher due to the high biomass and relative importance of termites in plant decomposition. Past research focused on net emission measurements and their variability, but little is known about underlying processes governing these emissions. In particular, microbial oxidation of methane (MOX) within termite mounds has rarely been investigated. In well-studied ecosystems featuring an oxic matrix above an anoxic methane-producing habitat (e.g. landfills or sediments), the fraction of oxidized methane (fox) can reach up to 90% of gross production. However, conventional mass-balance approaches to apportion production and consumption processes can be challenging to apply in the complex-structured and almost inaccessible environment of a termite mound. In effect, all field-based data on termite-mound MOX is based on one study that measured isotopic shifts in produced and emitted methane. In this study a closed-system isotope fractionation model was applied and estimated fox ranged from 10% to almost 100%. However, it is shown here that by applying an open-system isotope-pool model, the measured isotopic shifts can also be explained by physical transport of methane alone. Different field-based methods to quantify MOX in termite mounds are proposed which do not rely on assumptions of physical gas transport. A simple approach is the use of specific inhibitors for MOX, e.g. difluoromethane (CH2F2), combined with chamber-based flux measurements before and after their application. Data is presented on the suitability of different inhibitors and first results of their application in the field. Alternatively, gas-tracer methods allow the quantification of methane oxidation and reaction kinetics without knowledge of physical gas

  3. Microclimatic conditions of Lasius flavus ant mounds

    Science.gov (United States)

    Véle, Adam; Holuša, Jaroslav

    2017-05-01

    Like other organisms, ants require suitable microclimatic conditions for their development. Thus, ant species inhabiting colder climates build nest mounds that rise above the soil surface, presumably to obtain heating from solar radiation. Although some ant species construct mounds of organic materials, which generate substantial heat due to microbial metabolism, Lasius flavus mounds consists mostly of soil, not organic material. The use of artificial shading in the current study demonstrated that L. flavus depends on direct solar radiation to regulate the temperature in its mound-like nests. Temperatures were much lower in shaded mounds than in unshaded mounds and were likely low enough in shaded mounds to reduce ant development and reproduction. In areas where L. flavus and similar ants are undesirable, they might be managed by shading.

  4. Microclimatic conditions of Lasius flavus ant mounds

    Science.gov (United States)

    Véle, Adam; Holuša, Jaroslav

    2016-11-01

    Like other organisms, ants require suitable microclimatic conditions for their development. Thus, ant species inhabiting colder climates build nest mounds that rise above the soil surface, presumably to obtain heating from solar radiation. Although some ant species construct mounds of organic materials, which generate substantial heat due to microbial metabolism, Lasius flavus mounds consists mostly of soil, not organic material. The use of artificial shading in the current study demonstrated that L. flavus depends on direct solar radiation to regulate the temperature in its mound-like nests. Temperatures were much lower in shaded mounds than in unshaded mounds and were likely low enough in shaded mounds to reduce ant development and reproduction. In areas where L. flavus and similar ants are undesirable, they might be managed by shading.

  5. Effect of gas emissions from Tianchi volcano (NE China) on environment and its potential volcanic hazards

    Institute of Scientific and Technical Information of China (English)

    GUO; Zhengfu; LIU; Jiaqi; HAN; Jingtai; HE; Huaiyu; DAI; Guoliang; YOU; Haitao

    2006-01-01

    The Tianchi volcano in the Changbai Mountains is located on the boundary between China and North Korea. There are many times of eruptions of the Tianchi volcano during the Holocene. One of its large eruptions occurred around 1000 years ago dated by 14C method and historical records. Composition of products of the largest Tianchi volcanic eruption studied is characterized by comenditic Plinian fallout and unwelded ignimbrite, which are mainly distributed in China and North Korea. Caldera is about 4.4 km long and 3.4 km wide, which had filled with water (e.g. Tianchi Lake). The Tianchi volcanic cone is about 2700 m high above sea level. The Tianchi Lake is located on the summit of the volcanic cone, that is also highest peak of the Changbai Mountains in northeastern China. This study analyzed Cl, F, S and H2O concentrations of melt inclusions in the phenocryst minerals (anorthoclase and quartz) and co-existing matrix glasses using the electron microprobe and estimated environmental effect of Tianchi volcanic gases. The authors proposed a new method to evaluate future eruption of active volcano and estimate potential volcanic hazards based on contents of volatile emissions. Using this method, we made a perspective of future volcanic hazard in this region.

  6. Mound Facility publications for 1978

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-02-07

    This document is a compilation of all formal technical publications and oral presentations of Mound Facility in calendar year 1978. It is intended to serve as an aid to personnel in obtaining or referring to specifc publications by giving the proper complete reference for each information item published during the year. Some items may have issue dates or periods of coverage prior to 1978; however, they were formally published during 1978.

  7. One hundred volatile years of volcanic gas studies at the Hawaiian Volcano Observatory: Chapter 7 in Characteristics of Hawaiian volcanoes

    Science.gov (United States)

    Sutton, A.J.; Elias, Tamar; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

    2014-01-01

    The first volcanic gas studies in Hawai‘i, beginning in 1912, established that volatile emissions from Kīlauea Volcano contained mostly water vapor, in addition to carbon dioxide and sulfur dioxide. This straightforward discovery overturned a popular volatile theory of the day and, in the same action, helped affirm Thomas A. Jaggar, Jr.’s, vision of the Hawaiian Volcano Observatory (HVO) as a preeminent place to study volcanic processes. Decades later, the environmental movement produced a watershed of quantitative analytical tools that, after being tested at Kīlauea, became part of the regular monitoring effort at HVO. The resulting volatile emission and fumarole chemistry datasets are some of the most extensive on the planet. These data indicate that magma from the mantle enters the shallow magmatic system of Kīlauea sufficiently oversaturated in CO2 to produce turbulent flow. Passive degassing at Kīlauea’s summit that occurred from 1983 through 2007 yielded CO2-depleted, but SO2- and H2O-rich, rift eruptive gases. Beginning with the 2008 summit eruption, magma reaching the East Rift Zone eruption site became depleted of much of its volatile content at the summit eruptive vent before transport to Pu‘u ‘Ō‘ō. The volatile emissions of Hawaiian volcanoes are halogen-poor, relative to those of other basaltic systems. Information gained regarding intrinsic gas solubilities at Kīlauea and Mauna Loa, as well as the pressure-controlled nature of gas release, have provided useful tools for tracking eruptive activity. Regular CO2-emission-rate measurements at Kīlauea’s summit, together with surface-deformation and other data, detected an increase in deep magma supply more than a year before a corresponding surge in effusive activity. Correspondingly, HVO routinely uses SO2 emissions to study shallow eruptive processes and effusion rates. HVO gas studies and Kīlauea’s long-running East Rift Zone eruption also demonstrate that volatile emissions can

  8. Short-period volcanic gas precursors to phreatic eruptions: Insights from Poás Volcano, Costa Rica

    Science.gov (United States)

    de Moor, Maarten; Aiuppa, Alessandro; Pacheco, Javier; Avard, Geoffroy; Kern, Christoph; Liuzzo, Marco; Martinez, Maria; Giudice, Gaetano; Fischer, Tobias P.

    2016-01-01

    Volcanic eruptions involving interaction with water are amongst the most violent and unpredictable geologic phenomena on Earth. Phreatic eruptions are exceptionally difficult to forecast by traditional geophysical techniques. Here we report on short-term precursory variations in gas emissions related to phreatic blasts at Poás volcano, Costa Rica, as measured with an in situ multiple gas analyzer that was deployed at the edge of the erupting lake. Gas emitted from this hyper-acid crater lake approaches magmatic values of SO2/CO2 1–6 days prior to eruption. The SO2 flux derived from magmatic degassing through the lake is measureable by differential optical absorption spectrometry (sporadic campaign measurements), which allows us to constrain lake gas output and input for the major gas species during eruptive and non-eruptive periods. We can further calculate power supply to the hydrothermal system using volatile mass balance and thermodynamics, which indicates that the magmatic heat flux into the shallow hydrothermal system increases from ∼27 MW during quiescence to ∼59 MW during periods of phreatic events. These transient pulses of gas and heat from the deeper magmatic system generate both phreatic eruptions and the observed short-term changes in gas composition, because at high gas flux scrubbing of sulfur by the hydrothermal system is both kinetically and thermodynamically inhibited whereas CO2gas is always essentially inert in hyperacid conditions. Thus, the SO2/CO2 of lake emissions approaches magmatic values as gas and power supply to the sub-limnic hydrothermal system increase, vaporizing fluids and priming the hydrothermal system for eruption. Our results suggest that high-frequency real-time gas monitoring could provide useful short-term eruptive precursors at volcanoes prone to phreatic explosions.

  9. Formation Conditions and Distribution Regularities of Oil—gas Pools in Tertiary Volcanic Rocks in Western Huimin Depression,Shandong Province

    Institute of Scientific and Technical Information of China (English)

    刘泽容; 王永杰; 等

    1989-01-01

    The formation conditions and distribution regularities of oil-gas pools in volcanic rocks in western Huimin Depression have been studied in terms of geolgic,sesmic and well logging information,This paper discusses the types and lithofacies,development and distribution of Tertiary volcanic rocks in the area.The results demonstrate that volcanic activity occurred mainly during the period from the Sha-4 stage to the Guantao episode,i.e.,before the oil-generating period(before the end of the Guantao episode and the Minghuazhen episode).The activity did not destroy oil and gas formation and accumulation,but was favourable for the concentration of organic matter and its conversion to hydrocarbons;besides,volcanic rocks can serve as reservoir rocks and cap rocks,playing a role very similar to that of a syndepositional anticline,The volcanic rocks are distributed near the margins of the oil-generating depression;there are many secondary interstices in the rocks,which are connected with each other.These are the leading conditions for the formation of oil-generating period and their self-sealing or good combination with other cap rocks are important factors for forming volcanic rock-hosted oil and gas pools.The oil-gas pools associated with volcanic rocks in western Huimin are mainly distributed around the deep oil-generating depression,in the central up lift or the high structural levels on the margins of the depression.In particular,the sites where several faults cross are usually locatons where hith-yielding oil-gas pools in volcanic rocks are concentrated.

  10. Carbonate mound development in contrasting settings on the Irish margin

    NARCIS (Netherlands)

    van der Land, C.; Eisele, M.; Mienis, F; de Haas, H.; Hebbeln, D.; Reijmer, J.J.G.; van Weering, T.C.E.

    2014-01-01

    Cold-water coral carbonate mounds, formed by framework building cold-water corals, are found in several mound provinces on the Irish margin. Differences in cold-water coral mound development rates and sediment composition between mounds at the southwest Rockall Trough margin and the Galway Mound in

  11. Carbonate mound development in contrasting settings on the Irish margin

    NARCIS (Netherlands)

    van der Land, C.; Eisele, M.; Mienis, F; de Haas, H.; Hebbeln, D.; Reijmer, J.J.G.; van Weering, T.C.E.

    2014-01-01

    Cold-water coral carbonate mounds, formed by framework building cold-water corals, are found in several mound provinces on the Irish margin. Differences in cold-water coral mound development rates and sediment composition between mounds at the southwest Rockall Trough margin and the Galway Mound in

  12. Simulated Mima mounds emerge from small interactions

    CERN Document Server

    Lewis, Chloë Peregrine Hunt

    2011-01-01

    The Mima-mound-and-vernal-pool topography of California is rich in endemic plant and invertebrate species, but we do not know how this unusual environment is created or maintained. Burrowing rodents have been observed to move soil upwards at annual rates sufficient to maintain the mounds despite erosion, but there is no tested explanation of this behavior. We propose that the mounds are an emergent effect of small-scale (10 cm, 1 day) interactions between topography, hydrology, plant growth, and rodent burrowing. A cellular automata simulation of these processes both generates and maintains mound-pool topography with minimal dependence on initial conditions, and can also describe mound morphogenesis on slopes, where observed mound geometry is distinct from that on level ground.

  13. Carbonate budget of a cold-water coral carbonate mound: Propeller Mound, Porcupine Seabight

    Science.gov (United States)

    Dorschel, Boris; Hebbeln, Dierk; Rüggeberg, Andres; Dullo, Christian

    2007-02-01

    High resolution studies from the Propeller Mound, a cold-water coral carbonate mound in the NE Atlantic, show that this mound consists of >50% carbonate justifying the name ‘carbonate mound’. Through the last ~300,000 years approximately one third of the carbonate has been contributed by cold-water corals, namely Lophelia pertusa and Madrepora oculata. This coral bound contribution to the carbonate budget of Propeller Mound is probably accompanied by an unknown portion of sediments buffered from suspension by the corals. However, extended hiatuses in Propeller Mound sequences only allow the calculation of a net carbonate accumulation. Thus, net carbonate accumulation for the last 175 kyr accounts for only <0.3 g/cm2/kyr, which is even less than for the off-mound sediments. These data imply that Propeller Mound faces burial by hemipelagic sediments as has happened to numerous buried carbonate mounds found slightly to the north of the investigated area.

  14. Carbonate mound reservoirs in the paradox formation: An outcrop analogue along the San Juan River, Southeastern Utah

    Energy Technology Data Exchange (ETDEWEB)

    Chidsey, T. C. Jr.; Morgan, C.D. [Utah Geological Survey, Salt Lake City, UT (United States); Eby, D.E. [Eby Petrography & Consulting, Inc., Littleton, CO (United States)] [and others

    1996-06-01

    Carbonate mound reservoirs within the Pennsylvanian (Desmoinesian) Paradox Formation are major producers of oil and gas in the Paradox basin of Utah, Colorado, and Arizona. Outcrops of the Paradox Formation along the San Juan River of southeastern Utah provide small-scale analogues of reservoir heterogeneity, flow barriers and baffles, lithofacies, and geometry. These characteristics can be used in reservoir simulation models for secondary/tertiary recovery of oil from small fields in the basin. Exposures of the Paradox Formation Ismay zone in the Wild Horse Canyon area display lateral facies changes from phylloid algal mounds to off-mound detrital wedges or fans bounded at the top by a flooding surface. The phylloid mounds are composed of bafflestone, skeletal grainstone, packstone, and cementstone. Algal plates, brachiopods, bryozoans, and rugose corals are commonly found in the phylloid mounds. The mound wall is composed of rudstone, lumpstone, and cementstone. The detrital fan consists of transported algal material, grainstone, and mudstone with open-marine fossils. Within the mound complex is an inter-mound trough tentatively interpreted to be a tidal channel. The geometry and composition of the rocks in the trough significantly add to the overall heterogeneity of the mound. Reservoir models are being developed for possible water- and carbon-dioxide floods of small Paradox basin fields to determine the most effective secondary/tertiary recovery method. The models will include lithologic fabrics, flooding surfaces, and inter-mound troughs, based on the mound complex exposed at Wild Horse Canyon. This project may also provide reservoir information for simulation models in small Paleozoic carbonate mound fields in other basins worldwide.

  15. Gas/aerosol-ash interaction in volcanic plumes: New insights from surface analyses of fine ash particles

    Science.gov (United States)

    Delmelle, Pierre; Lambert, Mathieu; Dufrêne, Yves; Gerin, Patrick; Óskarsson, Niels

    2007-07-01

    The reactions occurring between gases/aerosols and silicate ash particles in volcanic eruption plumes remain poorly understood, despite the fact that they are at the origin of a range of volcanic, environmental, atmospheric and health effects. In this study, we apply X-ray photoelectron spectroscopy (XPS), a surface-sensitive technique, to determine the chemical composition of the near-surface region (2-10 nm) of nine ash samples collected from eight volcanoes. In addition, atomic force microscopy (AFM) is used to image the nanometer-scale surface structure of individual ash particles isolated from three samples. We demonstrate that rapid acid dissolution of ash occurs within eruption plumes. This process is favoured by the presence of fluoride and is believed to supply the cations involved in the deposition of sulphate and halide salts onto ash. AFM imaging also has permitted the detection of extremely thin (< 10 nm) coatings on the surface of ash. This material is probably composed of soluble sulphate and halide salts mixed with sparingly soluble fluoride compounds. The surface approach developed here offers promising aspects for better appraising the role of gas/aerosol-ash interaction in dictating the ability of ash to act as sinks for various volcanic and atmospheric chemical species as well as sources for others.

  16. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1994-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...... of the rock material are functions of rock type and the degree of weathering. Thus it is important to establish the availability and quality of rock material before completion of a breakwater design for a particular location. If this is not possible then design changes are to be foreseen during...

  17. Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    Rubble mound breakwaters require availability of often very large quantities of rock materials of various gradings and qualities. Because natural stones are seldom available in sufficient quantities and sizes the materials must in most cases be supplied from quarries. The output from a quarry...... the construction stage. Anyway, it is seldom that a fair amount of rocks of mass larger than 10-15 t can be produced, even in good quality quarries. If heavier blocks are needed concrete armour units or vertical structures must be considered....

  18. Carbonate mound development in contrasting settings on the Irish margin

    Science.gov (United States)

    van der Land, Cees; Eisele, Markus; Mienis, Furu; de Haas, Henk; Hebbeln, Dierk; Reijmer, John J. G.; van Weering, Tjeerd C. E.

    2014-01-01

    Cold-water coral carbonate mounds, formed by framework building cold-water corals, are found in several mound provinces on the Irish margin. Differences in cold-water coral mound development rates and sediment composition between mounds at the southwest Rockall Trough margin and the Galway Mound in the Porcupine Seabight are investigated. Variations in sediment composition in the two mound provinces are related to the local environmental conditions and sediment sources. Mound accumulation rates are possibly higher at the Galway Mound probably due to a higher influx of hemipelagic fine grained non-carbonate sediments. In both cold-water coral mound areas, mound growth has been continuous for the last ca 11,000 years, before this period several hiatuses and unconformities exist in the mound record. The most recent unconformity can be correlated across multiple mounds and mound provinces at the Irish margin on the basis of apparent age. On the southwest Rockall Trough margin these hiatuses/unconformities are associated with post-depositional aragonite dissolution in, and lithification of, certain intervals, while at Galway Mound no lithification occurs. This study revealed that the influx and types of material transported to cold-water coral mounds may have a direct impact on the carbonate mound accumulation rate and on post-depositional processes. Significantly, the Logachev Mounds on the SW Rockall Trough margin accumulate slower but, because they contain lithified layers, are less susceptible to erosion. This net effect may account for their larger size compared to the Belgica Mounds.

  19. 'Failed' eruptions revealed by integrated analysis of gas emission and volcanic tremor data at Mt. Etna, Italy

    Science.gov (United States)

    Salerno, G. G.; Falsaperla, S. M.; Behncke, B.; Langer, H. K.; Neri, M.; Giammanco, S.; Pecora, E.; Biale, E.

    2013-12-01

    Mt Etna in Sicily is among the most intensely monitored and studied volcanoes on Earth due to its very frequent activity, and its location in a densely populated area. Through a sophisticated monitoring system run by the Istituto Nazionale di Geofisica e Vulcanologia - Osservatorio Etneo (INGV-OE), scientists are gaining every day and in real time a picture of the state of volcanic activity of Etna. During the spring of 2007, various episodes of paroxysmal activity occurred at the South-East Crater, one of the four summit craters of Mt Etna. These episodes were always associated with a sharp increase in the amplitude of the volcanic tremor as well as changes in the spectral characteristics of this signal. Eruptive activity ranged from strong Strombolian explosions to lava fountains coupled with copious emission of lava flows and tephra. During inter-eruptive periods, recurrent seismic unrest episodes were observed in form of both temporary enhancements of the volcanic tremor amplitude as well as changes of spectral characteristics. These changes often triggered the automatic alert systems in the operation room of the INGV-OE, even though not being followed by manifest eruptive activity at the surface. The influence of man-made or meteorologically induced noise could be ruled out as a cause for the alarms. We therefore performed a multi-parametric analysis of these inter-eruptive periods by integrating seismic volcanic tremor, in-soil radon, plume SO2 flux and thermal data, discussing the potential volcano-dependent source of these episodes. Short-term changes were investigated applying pattern classification, in particular Kohonen Maps and fuzzy clustering, simultaneously on volcanic tremor, radon and ambient parameters (pressure and temperature). The well established SO2 flux and thermal radiation data were used as the 'smoking gun', for certifying that the observed changes in seismic and in radon data can be considered as volcanogenic. Our results unveil ';failed

  20. Sulphur Extraction at Bryan Mound

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Carolyn L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, Anna C. Snider [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    The Bryan Mound caprock was subjected to extens ive sulphur mining prior to the development of the Strategic Petroleum Reserve. Undoubtedl y, the mining has modified the caprock integrity. Cavern wells at Bryan Mound have been subject to a host of well integr ity concerns with many likely compromised by the cavernous capro ck, surrounding corrosive environment (H 2 SO 4 ), and associated elevated residual temperatures al l of which are a product of the mining activities. The intent of this study was to understand the sulphur mining process and how the mining has affected the stability of the caprock and how the compromised caprock has influenced the integrity of the cavern wells. After an extensiv e search to collect pert inent information through state agencies, literature sear ches, and the Sandia SPR librar y, a better understanding of the caprock can be inferred from the knowledge gaine d. Specifically, the discovery of the original ore reserve map goes a long way towards modeling caprock stability. In addition the gained knowledge of sulphur mining - subs idence, superheated corrosive wa ters, and caprock collapse - helps to better predict the post mi ning effects on wellbore integrity. This page intentionally left blank

  1. COCARDE: new view on old mounds - an international network of carbonate mound research

    Science.gov (United States)

    Rüggeberg, A.; Foubert, A.; Vertino, A.; van Rooij, D.; Spezzaferri, S.; Henriet, J.-P.; Dullo, W.-C.; Cocarde Science Community

    2012-04-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern cold-water coral carbonate mounds over the last decades made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community with cold-water corals as main framework builders, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (http://www.cocarde.eu) is a platform for exploring new insights in carbonate mound research of recent and ancient mound systems. The aim of the COCARDE network is to bring together scientific communities, studying Recent carbonate mounds in midslope environments in the present ocean and investigating fossil mounds spanning the whole Phanerozoic time, respectively. Scientific challenges in modern and ancient carbonate mound research got well defined during the ESF Magellan Workshop COCARDE in Fribourg, Switzerland (21.-24.01.2009). The Special Volume Cold-water Carbonate Reservoir systems in Deep Environments - COCARDE (Marine Geology, Vol. 282) was the major outcome of this meeting and highlights the diversity of Recent carbonate mound studies. The following first joint Workshop and Field Seminar held in Oviedo, Spain (16.-20.09.2009) highlighted ongoing research from both Recent and fossil academic groups integrating the message from the industry. The field seminar focused on mounds from the Carboniferous platform of Asturias and Cantabria, already intensively visited by industrial and academic researchers. However, by comparing ancient, mixed carbonate-siliciclastic mound systems of Cantabria with the Recent ones in the Porcupine Seabight, striking similarities in their genesis and processes in mound development asked for an integrated drilling campaign to understand better the 3D internal mound build-up. The

  2. Development and application of a sampling method for the determination of reactive halogen species in volcanic gas emissions

    Science.gov (United States)

    Rüdiger, Julian; Bobrowski, Nicole; Liotta, Marcello; Hoffmann, Thorsten

    2017-04-01

    Volcanoes are a potential large source of several reactive atmospheric trace gases including sulfur and halogen containing species. Besides the importance for atmospheric chemistry, the detailed knowledge of halogen chemistry in volcanic plumes can help to get insights into subsurface processes. In this study a gas diffusion denuder sampling method, using a 1,3,5-trimethoxybenzene (1,3,5-TMB) coating for the derivatization of reactive halogen species (RHS), was characterized by dilution chamber experiments. The coating proved to be suitable to collect selectively gaseous bromine species with oxidation states (OS) of +1 or 0 (such as Br2, BrCl, BrO(H) and BrONO2), while being ignorant to HBr (OS -1). The reaction of 1,3,5-TMB with reactive bromine species gives 1-bromo-2,4,6-trimethoxybenzene (1-bromo-2,4,6-TMB) - other halogens give corresponding products. Solvent elution of the derivatized analytes and subsequent analysis with gas chromatography mass spectrometry gives detection limits of 10 ng or less for Br2, Cl2, and I2. In 2015 the method was applied on volcanic gas plumes at Mt. Etna (Italy) giving reactive bromine mixing ratios from 0.8 ppbv to 7.0 ppbv. Total bromine mixing ratios of 4.7 ppbv to 27.5 ppbv were obtained by simultaneous alkaline trap sampling (by a Raschig-tube) followed by analysis with ion chromatography and inductively coupled plasma mass spectrometry. This leads to the first results of in-situ measured reactive bromine to total bromine ratios, spanning a range between 12±1 % and 36±2 %. Our finding is in an agreement with previous model studies, which imply values < 44 % for plume ages < 1 minute, which is consistent with the assumed plume age at the sampling sites.

  3. Termite mound emissions of CH4 and CO2 are primarily determined by seasonal changes in termite biomass and behaviour.

    Science.gov (United States)

    Jamali, Hizbullah; Livesley, Stephen J; Dawes, Tracy Z; Hutley, Lindsay B; Arndt, Stefan K

    2011-10-01

    Termites are a highly uncertain component in the global source budgets of CH(4) and CO(2). Large seasonal variations in termite mound fluxes of CH(4) and CO(2) have been reported in tropical savannas but the reason for this is largely unknown. This paper investigated the processes that govern these seasonal variations in CH(4) and CO(2) fluxes from the mounds of Microcerotermes nervosus Hill (Termitidae), a common termite species in Australian tropical savannas. Fluxes of CH(4) and CO(2) of termite mounds were 3.5-fold greater in the wet season as compared to the dry season and were a direct function of termite biomass. Termite biomass in mound samples was tenfold greater in the wet season compared to the dry season. When expressed per unit termite biomass, termite fluxes were only 1.2 (CH(4)) and 1.4 (CO(2))-fold greater in the wet season as compared to the dry season and could not explain the large seasonal variations in mound fluxes of CH(4) and CO(2). Seasonal variation in both gas diffusivity through mound walls and CH(4) oxidation by mound material was negligible. These results highlight for the first time that seasonal termite population dynamics are the main driver for the observed seasonal differences in mound fluxes of CH(4) and CO(2). These findings highlight the need to combine measurements of gas fluxes from termite mounds with detailed studies of termite population dynamics to reduce the uncertainty in quantifying seasonal variations in termite mound fluxes of CH(4) and CO(2).

  4. Magma-derived gas influx and water-rock interactions in the volcanic aquifer of Mt. Vesuvius, Italy

    Science.gov (United States)

    Federico, C.; Aiuppa, A.; Allard, P.; Bellomo, S.; Jean-Baptiste, P.; Parello, F.; Valenza, M.

    2002-03-01

    We report in this paper a systematic investigation of the chemical and isotopic composition of groundwaters flowing in the volcanic aquifer of Mt. Vesuvius during its current phase of dormancy, including the first data on dissolved helium isotope composition and tritium content. The relevant results on dissolved He and C presented in this paper reveal that an extensive interaction between rising magmatic volatiles and groundwaters currently takes place at Vesuvius. Vesuvius groundwaters are dilute (mean TDS ˜ 2800 mg/L) hypothermal fluids ( mean T = 17.7°C) with a prevalent alkaline-bicarbonate composition. Calcium-bicarbonate groundwaters normally occur on the surrounding Campanian Plain, likely recharged from the Apennines. δD and δ 18O data evidence an essentially meteoric origin of Vesuvius groundwaters, the contribution from either Tyrrhenian seawater or 18O-enriched thermal water appearing to be small or negligible. However, the dissolution of CO 2-rich gases at depth promotes acid alteration and isochemical leaching of the permeable volcanic rocks, which explains the generally low pH and high total carbon content of waters. Attainment of chemical equilibrium between the rock and the weathering solutions is prevented by commonly low temperature (10 to 28°C) and acid-reducing conditions. The chemical and isotope (C and He) composition of dissolved gases highlights the magmatic origin of the gas phase feeding the aquifer. We show that although the pristine magmatic composition may vary upon gas ascent because of either dilution by a soil-atmospheric component or fractionation processes during interaction with the aquifer, both 13C/ 12C and 3He/ 4He measurements indicate the contribution of a magmatic component with a δ 13C ˜ 0‰ and R/R a of ˜2.7, which is consistent with data from Vesuvius fumaroles and phenocryst melt inclusions in olivine phenocrysts. A main control of tectonics on gas ascent is revealed by data presented in this paper. For example

  5. Volcanic ash ingestion by a large gas turbine aeroengine: fan-particle interaction

    Science.gov (United States)

    Vogel, Andreas; Clarkson, Rory; Durant, Adam; Cassiani, Massimo; Stohl, Andreas

    2016-04-01

    Airborne particles from explosive volcanic eruptions are a major safety threat for aviation operations. The fine fraction of the emitted particles ( 20 microns) tend to be transported into the bypass duct of the engine (by the centrifugal effect of the fan), whereas the smaller particles follow the fluid flow streamlines and are distributed homogenously in the engine (bypass ducts and core region). This result is significant as it indicates that the absolute ash mass that causes issues for aeroengine operation is a fraction of the ambient (observed or forecast) ash quantity.

  6. Light-noble-gas isotopic ratios in gases from Mt. Etna (Southern Italy). Implications for mantle contamination and volcanic activity

    Energy Technology Data Exchange (ETDEWEB)

    Italiano, F. [Consiglio Nazionale delle Ricerche, Palermo (Italy). Ist. di Geochimica dei Fluidi; Nuccio, P.M. [Palermo Univ., Palermo (Italy). Ist. di Mineralogia, Petrografia e Geochimica; Nakai, S. [Tokyo Univ., Tokyo (Japan). Lab. for Earthquake Chemistry; Wakita, H. [Tokyo Univ., Tokyo (Japan). Earthquake Research Inst.

    1999-08-01

    Taking into account the light-noble-isotopic ratios signature of gas samples coming from the Etnean area (Southern Italy), it seems that in this area the crustal contamination played a minor role. Instead, processes that enriched the original MORB-type mantle in incompatible elements, have to be considered. The {sup 3}He/{sup 4}He ratios are, thus, lowered because of {sup 1}He produced by radioactive decay of U and Th. On the other hand, helium isotopic ratios have shown wide temporal variations sometimes reaching values as high as 7.6 Ra, out pf typical Etnean range. As these unusually high ratios have been measured during phases of unrest of the volcanic activity at Mt. Etna, this apparent discrepancy in the helium isotopic ratios is considered, as the effect of fractionation processes occurred during the magma uprising.

  7. Dynamics and Evolution of SO2 Gas Condensation Around Prometheus-like Volcanic Plumes on Io as Seen by the Near Infrared Mapping Spectrometer

    Science.gov (United States)

    Doute, S.; Lopes-Gautier, R.; Smythe, W. D.; Kamp, L. W.; Carlson, R.

    2001-01-01

    Near Infrared Mapping Spectrometer data acquired during the I24, 25, and 27 Io's Fly-bys by Galileo are analyzed to map the SO2 frost abundance and granularity. This allows a better understanding of the dynamics and evolution of gas condensation around volcanic plumes. Additional information is contained in the original extended abstract.

  8. The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

    Directory of Open Access Journals (Sweden)

    A. Aiuppa

    2007-01-01

    Full Text Available Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily. Sulphur dioxide (SO2, hydrogen sulphide (H2S, hydrogen chloride (HCl and hydrogen fluoride (HF concentrations in the volcanic plumes (typically several minutes to a few hours old were repeatedly determined at distances from the summit vents ranging from 0.1 to ~10 km, and under different environmental conditions. At both volcanoes, acidic gas concentrations were found to decrease exponentially with distance from the summit vents (e.g., SO2 decreases from ~10 000 μg/m3at 0.1 km from Etna's vents down to ~7 μg/m3 at ~10 km distance, reflecting the atmospheric dilution of the plume within the acid gas-free background troposphere. Conversely, SO2/HCl, SO2/HF, and SO2/H2S ratios in the plume showed no systematic changes with plume aging, and fit source compositions within analytical error. Assuming that SO2 losses by reaction are small during short-range atmospheric transport within quiescent (ash-free volcanic plumes, our observations suggest that, for these short transport distances, atmospheric reactions for H2S and halogens are also negligible. The one-dimensional model MISTRA was used to simulate quantitatively the evolution of halogen and sulphur compounds in the plume of Mt. Etna. Model predictions support the hypothesis of minor HCl chemical processing during plume transport, at least in cloud-free conditions. Larger

  9. Affluence of Data on Volcanism in The Gulf of Cadiz

    Directory of Open Access Journals (Sweden)

    E Wulff-Barreiro

    2009-04-01

    Full Text Available This paper reports the recent progress on mud volcanism data accumulation in the case of the Gulf of Cadiz area. The discovery of giant mud volcanoes, deep coral reefs, and gas hydrates in 1999, from the Guadalquivir Diapiric Ridge to the Larache Moroccan margin, launched a dynamic expansion of new projects (GeNesis, MoundForce, HERMES and international oceanographic campaigns (R/V Sonne, Marion-Dufresne. The present monitoring of this Ibero-Moroccan oceanic zone is in need of a comprehensive database available in one site to make online search possible from a single interface. The database would constitute a reference point for a focused full scope collection.

  10. The Role of Volcanic Sour Gas on the Alteration of Martian Basalt: Insights from Geochemical Modeling

    Science.gov (United States)

    Berger, G.; Treguier, E.; D'Uston, C.; Pinet, P.; Toplis, M. J.

    2008-03-01

    We assess the chemical constraints of the alteration of basaltic material by a cold aqueous phase under atmospheric sour gas containing SO3. Secondary chemistry and mineralogy are calculated by a geochemical simulator and compared to MER data.

  11. Gas emission from diffuse degassing structures (DDS) of the Cameroon volcanic line (CVL): Implications for the prevention of CO2-related hazards

    Science.gov (United States)

    Issa; Ohba, T.; Chako Tchamabé, B.; Padrón, E.; Hernández, P.; Eneke Takem, E. G.; Barrancos, J.; Sighomnoun, D.; Ooki, S.; Nkamdjou, Sigha; Kusakabe, M.; Yoshida, Y.; Dionis, S.

    2014-08-01

    In the mid-1980s, lakes Nyos and Monoun violently released massive gas, mainly magmatic CO2 killing about 1800 people. Subsequent geochemical surveys and social studies indicate that lakes Nyos and Monoun event is cyclic in nature and may occur anywhere in the about 37 other volcanic lakes located in the corridor of the Cameroon volcanic line (CVL). This potential threat motivated us to check if, alike Nyos and Monoun, the internal dynamic of the other lakes is also controlled by inputs of deep-seated-derived CO2 and attempt to measure and provide comprehensive insights on the passive gas emission along the CVL. This knowledge shall contribute to the prevention of volcanic lake-related hazards in Cameroon and the refinement of the Global Carbon Cycle. We used in situ fixation and dry gas phase sampling methods to determine CO2 origin and the concentration, and the accumulation chamber technique to measure diffuse CO2 emission from nine lakes and on soil at Nyos Valley and Mount Manenguba Caldera. The results suggest that, although in minor concentrations (compared to Nyos and Monoun), ranging from 0.56 mmol kg- 1 to 8.75 mmol kg- 1, the bottom waters of some lakes also contain measurable magmatic CO2 with δ13C varies from - 4.42‰ to - 9.16‰ vs. PDB. That finding implies that, under certain circumstances, e.g. increase to volcanic and/or tectonic activities along the CVL, the concerned lakes could develop a Nyos-type behavioural scheme. The diffuse gas emission results indicate that the nine surveyed lakes release approximately 3.69 ± 0.37 kt km- 2 yr- 1 of CO2 to the atmosphere; extrapolation to the approximately 39 volcanic lakes located on the CVL yields an approximate CO2 output of 27.37 ± 0.5 kt km- 2 yr- 1, representing 0.023% of the global CO2 output from volcanic lakes. In addition to the precedent value, the gas removal operation in lakes Nyos and Monoun released approximately 2.52 ± 0.46 × 108 mol km- 2 yr- 1 CO2 to the atmosphere from January

  12. Ground based measurements of the gas emission from the Holuhraun volcanic fissure eruption on Iceland 2014/2015

    Science.gov (United States)

    Galle, Bo; Arellano, Santiago; Conde, Vladimir; Pfeffer, Melissa; Barsotti, Sara; Stefansdottir, Gerður; Bergsson, Baldur; Bergsson, Bergur; Ingvarsson, Thorgils; Weber, Konradin

    2015-04-01

    The since 31 August 2014 ongoing volcanic eruption at Holuhraun on Iceland is by far the strongest source of sulfur dioxide in Europe over the last 230 years with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affects local population and has become a concern also for air traffic. The eruption has in December continued at constant pace for 3.5 months. Three scenarios are envisaged for the future; (1) the eruption stops, (2) the fissure extends under the Vattnajökul glacier and (3) Bardarbunga volcano erupts. The two later scenarios will cause increased gas emission, severe ash emissions and extended flooding. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, we are developing a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions. Since the first day of the eruption several of these novel instruments has been monitoring the SO2 emission from the eruption. Data from our instruments are still after 3.5 months the only sustained ground-based monitoring of this gas emission. A lot of work is however needed to sustain this operation at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions require the development of novel methods to derive reliable flux estimates. In this presentation we will discuss the instrumental issues and present the latest version of the emission estimates made from our measurements.

  13. Seafloor doming driven by degassing processes unveils sprouting volcanism in coastal areas

    Science.gov (United States)

    Passaro, Salvatore; Tamburrino, Stella; Vallefuoco, Mattia; Tassi, Franco; Vaselli, Orlando; Giannini, Luciano; Chiodini, Giovanni; Caliro, Stefano; Sacchi, Marco; Rizzo, Andrea Luca; Ventura, Guido

    2016-03-01

    We report evidences of active seabed doming and gas discharge few kilometers offshore from the Naples harbor (Italy). Pockmarks, mounds, and craters characterize the seabed. These morphologies represent the top of shallow crustal structures including pagodas, faults and folds affecting the present-day seabed. They record upraise, pressurization, and release of He and CO2 from mantle melts and decarbonation reactions of crustal rocks. These gases are likely similar to those that feed the hydrothermal systems of the Ischia, Campi Flegrei and Somma-Vesuvius active volcanoes, suggesting the occurrence of a mantle source variously mixed to crustal fluids beneath the Gulf of Naples. The seafloor swelling and breaching by gas upraising and pressurization processes require overpressures in the order of 2-3 MPa. Seabed doming, faulting, and gas discharge are manifestations of non-volcanic unrests potentially preluding submarine eruptions and/or hydrothermal explosions.

  14. Environmental changes and growth history of a cold-water carbonate mound (Propeller Mound, Porcupine Seabight)

    Science.gov (United States)

    Rüggeberg, Andres; Dullo, Christian; Dorschel, Boris; Hebbeln, Dierk

    2007-02-01

    On- and off-mound sediment cores from Propeller Mound (Hovland Mound province, Porcupine Seabight) were analysed to understand better the evolution of a carbonate mound. The evaluation of benthic foraminiferal assemblages from the off-mound position helps to determine the changes of the environmental controls on Propeller Mound in glacial and interglacial times. Two different assemblages describe the Holocene and Marine Isotope Stage (MIS) 2 and late MIS 3 (˜31 kyr BP). The different assemblages are related to changes in oceanographic conditions, surface productivity and the waxing and waning of the British Irish Ice Sheet (BIIS) during the last glacial stages. The interglacial assemblage is related to a higher supply of organic material and stronger current intensities in water depth of recent coral growth. During the last glaciation the benthic faunas showed high abundances of cassidulinid species, implying cold bottom waters and a reduced availability of organic matter. High sedimentation rates and the domination of Elphidium excavatum point to shelf erosion related to sea-level lowering (˜50 m) and the progradation of the BIIS onto the shelf. A different assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species are only found or show significantly higher relative abundances in on-mound samples and their maximum contribution in the lower part of the record indicates a higher coral growth density on Propeller Mound in an earlier period. They are less abundant during the Holocene, however. This dataset portrays the boundary conditions of the habitable range for the cold-water coral Lophelia pertusa, which dominates the deep-water reefal ecosystem on the upper flanks of Propeller Mound. The growth of this ecosystem occurs during interglacial and interstadial periods, whereas a retreat of corals is documented in

  15. Insights from gas and water chemistry on the geothermal system of the Domuyo volcanic complex (Patagonia, Argentina)

    Science.gov (United States)

    Tassi, F.; Liccioli, C.; Chiodini, G.; Agusto, M.; Caselli, A. T.; Caliro, S.; Vaselli, O.; Pecoraino, G.

    2015-12-01

    This study focuses on the geochemistry of geothermal fluids discharging from the western flank of the Domuyo volcanic complex (Argentina), which is hosted within an extensional basins that interrupts the Andes at latitudes comprises between 35° and 39°S. The analytical results of gas and water samples collected during three sampling campaigns (2013, 2014 and 2015) are presented and discussed in order to: i) evaluate the equilibrium temperature(s) of the main fluid reservoir, ii) provide information on the origin of the fluid discharges and the secondary processes controlling their chemistry. Geothermometry based on the chemical composition of thermal waters indicates a maximum equilibrium temperature of 220 °C. This temperature, coupled with the measured amount of discharged Cl, suggest that the total energy released from this system is 1.1±0.2 GW. Atmospheric gases from a thick shallow aquifer contaminate most gas emissions, masking the chemical features of the deep fluid component, with the only exception of a jet fumarole located at 3,000 m a.s.l. (Bramadora). The H2O-CO2-CH4-H2-CO-C3H6-C3H8 composition of this gas emission was used to construct a geochemical conceptual model showing that the hydrothermal reservoir is liquid-dominated and thermally stratified, with temperatures ranging from 180 to 270 °C. The helium isotopic ratios (up to 6.8 Ra) and the δ13C-CO2 values (from -7.05 to -7.75 ‰ V-PDB) indicate that mantle degassing represents the dominant primary source for this dormant volcano. These results highlight the huge potential of this system as energy resource for the region. Accordingly, the regional authorities have recently planned and approved an investigation project aimed to provide further insights into the fluid geochemistry and the geostructural assessment in this promising area.

  16. Preliminary Results from IODP Expedition 307, Porcupine Basin Carbonate Mounds

    Science.gov (United States)

    Williams, T.; Kano, A.; Ferdelman, T.; Henriet, J.; Shipboard Scientific Party, I.

    2005-12-01

    IODP Expedition 307 (April 26 - May 16, 2005) drilled three sites at Challenger Mound in the Porcupine Seabight, west of Ireland. Deep-water carbonate mounds up to 2 km wide and 200 m high have been found in typical water depths of 500-1000 m along the continental slope of NW Europe from Morocco to Norway. During the last ten years they have been studied using seismics, shallow coring, high resolution bathymetry, and remotely operated vehicles. The partly-buried Challenger Mound is the first to be completely cored to the mound base, with the aim of answering basic questions such as: What is the sedimentology and structure of the mound? What triggered mound initiation? How does the ecosystem interact with sedimentary fluxes to make the mound grow? How are mound growth phases related to glacial-interglacial cycles? What role do microbial communities and geochemical reaction play in the mound? Analytical work is at an early stage, but already shipboard results reveal some of the mound's secrets. The mound body consists of a 155-m-thick sequence of cold-water coral-bearing Pleistocene sediments (floatstone, rudstone, and wackestone), characterized by 10-meter-scale alternation of light gray and dark green intervals. The carbonate-rich and light-colored layers are partially lithified and feature poor coral preservation or even dissolution. The mound base, virtually identical in the on-mound and off-mound holes, is a sharp Pliocene erosional unconformity, separating coral-bearing sediments from a glauconitic and partly sandy siltstone. No evidence was found for a relation between mound development and hydrocarbon seepage. The results from Challenger Mound will help provide a depositional model with which to interpret deep water carbonate mounds in the geological rock record, and we look forward to future drilling of contrasting carbonate mounds.

  17. A cold-water coral carbonate mound on the decline: Propeller Mound, northern Porcupine Seabight

    Science.gov (United States)

    Dorschel, B.; Hebbeln, D.; Rüggeberg, A.; Dullo, C.

    2003-04-01

    Radiocarbon and U/Th datings reveal that the top sediment sequence of the Propeller Mound in the Hovland Mound Province is incomplete and characterised by numerous hiatuses. Stable oxygen isotope data obtained on benthic foraminifera indicate that almost only interstadial sediments are preserved, while interglacial and full glacial sediments are missing. The Mediterranean Outflow Water (MOW), assumed to be crucial for the development of the cold-water corals Lophelia pertusa and Madrepora occulata found on Propeller Mound and in its sediments, reaches the Porcupine Seabight in its full strength only during interglacials, while it is absent during glacials. ROV observations show that under present-day conditions the MOW supports coral growth at the top of Propeller Mound, while at the same time it causes substantial erosion on its flanks, where scouring might lead to subsequent slumping. Thus, the hiatuses found in the sediment sequence of Propeller Mound are most likely caused by the strong bottom currents associated with the MOW. Especially during the terminations when the MOW circulation was re-established most of the glacial sediments, deposited under rather smooth conditions, might have been eroded and/or wasted downslope. Such erosion-favourable conditions lasted through the interglacials resulting in the ongoing removal of the interglacial sediments. During the interstadials the interplay between bottom current strength, coral growth and sedimentation resulted in sediment sequences which had a bigger chance to get preserved. Through the last 300 000 years the netto sedimentation on Propeller Mound is by far less compared to the surrounding off-mound sediments. Thus, at least over this time span the mound is shrinking relative to the seafloor around it and if this development continues into the future the Propeller Mound will get buried and follow the fate of the already buried near-by Magellan Mounds.

  18. Validation of a novel Multi-Gas sensor for volcanic HCl alongside H2S and SO2 at Mt. Etna

    Science.gov (United States)

    Roberts, T. J.; Lurton, T.; Giudice, G.; Liuzzo, M.; Aiuppa, A.; Coltelli, M.; Vignelles, D.; Salerno, G.; Couté, B.; Chartier, M.; Baron, R.; Saffell, J. R.; Scaillet, B.

    2017-05-01

    Volcanic gas emission measurements inform predictions of hazard and atmospheric impacts. For these measurements, Multi-Gas sensors provide low-cost in situ monitoring of gas composition but to date have lacked the ability to detect halogens. Here, two Multi-Gas instruments characterized passive outgassing emissions from Mt. Etna's (Italy) three summit craters, Voragine (VOR), North-east Crater (NEC) and Bocca Nuova (BN) on 2 October 2013. Signal processing (Sensor Response Model, SRM) approaches are used to analyse H2S/SO2 and HCl/SO2 ratios. A new ability to monitor volcanic HCl using miniature electrochemical sensors is here demonstrated. A "direct-exposure" Multi-Gas instrument contained SO2, H2S and HCl sensors, whose sensitivities, cross-sensitivities and response times were characterized by laboratory calibration. SRM analysis of the field data yields H2S/SO2 and HCl/SO2 molar ratios, finding H2S/SO2 = 0.02 (0.01-0.03), with distinct HCl/SO2 for the VOR, NEC and BN crater emissions of 0.41 (0.38-0.43), 0.58 (0.54-0.60) and 0.20 (0.17-0.33). A second Multi-Gas instrument provided CO2/SO2 and H2O/SO2 and enabled cross-comparison of SO2. The Multi-Gas-measured SO2-HCl-H2S-CO2-H2O compositions provide insights into volcanic outgassing. H2S/SO2 ratios indicate gas equilibration at slightly below magmatic temperatures, assuming that the magmatic redox state is preserved. Low SO2/HCl alongside low CO2/SO2 indicates a partially outgassed magma source. We highlight the potential for low-cost HCl sensing of H2S-poor HCl-rich volcanic emissions elsewhere. Further tests are needed for H2S-rich plumes and for long-term monitoring. Our study brings two new advances to volcano hazard monitoring: real-time in situ measurement of HCl and improved Multi-Gas SRM measurements of gas ratios.

  19. Structure of a carbonate/hydrate mound in the northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    McGee, T.; Woolsey, J.; Macelloni, L. [Mississippi Univ., Oxford, MI (United States). Center for Marine Resources and Environmental Technology; Lapham, L. [Florida State Univ., Tallahassee, FL (United States); Kleinberg, R. [Schlumberger-Doll Research, Cambridge, MA (United States); Battista, B.; Knapp, C. [South Carolina Univ., Columbia, SC (United States); Caruso, S. [Univ. of Rome La Sapienza, Rome, (Italy). Dept. of Geological Sciences; Goebel, V. [Lookout Geophysical Co., Palisade, CO (United States); Chapman, R. [Victoria Univ., BC (Canada). School of Earth and Ocean Sciences; Gerstoft, P. [California Univ., San Diego, CA (United States). Marine Physical Laboratory

    2008-07-01

    A one-kilometer-diameter carbonate/hydrate mound located in the south-central portion of Mississippi Canyon block 118 in the Gulf of Mexico was the site of a multi-sensor, multi-discipline sea-floor observatory. In preparation for installing the observatory, several surveys were conducted. The resulting data provided detailed information about the mound's structure. This paper discussed the structure of the carbonate/hydrate mound in the Gulf of Mexico. The paper described the surface morphology of the mound, which was imaged by multi-beam bathymetric sonar from an autonomous underwater vehicle (AUV) 40 metres above the sea floor as well as by cameras at or a few meters above the sea floor deployed from drifting surface vessels or tethered submersibles. Visual observations were also made from manned submersibles. The paper also discussed the collection of gravity and box cores for lithologic and bio-geochemical studies. Gas sampling, venting activity, and seismo-acoustic studies were also presented. The internal structure of the mound was described as well. It was concluded that pore-fluid analyses conducted on the cores revealed that microbial sulfate reduction, anaerobic methane oxidation, and methanogenesis were important processes in the upper sediment as they controlled the diffusive flux of methane into the overlying water column. The activity of microbes was also focused within patches near active vents. 10 refs., 10 figs.

  20. Development and application of gas diffusion denuder sampling techniques with in situ derivatization for the determination of hydrogen halides in volcanic plumes

    Science.gov (United States)

    Gutmann, Alexandra; Rüdiger, Julian; Bobrowski, Nicole; Hoffmann, Thorsten

    2017-04-01

    Volcanoes emit large amounts of gases into the atmosphere. The gas composition in volcanic plumes vary, driven by subsurface processes (such as magma rising) as well as by chemical reactions within the plume after mixing with ambient air. The knowledge of the gas composition can be a useful tool to monitor volcanic activity changes. However, to use the plume composition as a monitoring parameter, it is essential to understand the chemical reactions inside volcanic plumes, in particular when interpretation of volcanic activity changes is based on reactive gas species, such as bromine monoxide or molecular halogens. Changes in BrO/SO2-ratios, measured by UV spectrometers, have already been interpreted in connection with increasing volcanic activity prior to eruptions. But the abundance of BrO changes as a function of the reaction time, and therefore with distance from the vent, as well as the spatial position in the plume. Actually model and field studies assume a non-direct emission of BrO, but its formation due to photochemical and multiphase reactions involving gas and particle phase of volcanic emission mixed with the surrounding atmosphere. However, same models presume HBr as initially emitted species. Therefore, HBr is an important species linking BrO to geophysical processes in volcanic systems. Due to the lack of analytical methods for the accurate speciation of certain halogens (HBr, Br2, Br, BrCl, HOBr, etc.) there are still large uncertainties about the magnitude of volcanic halogen emissions, and in the understanding of the bromine chemistry in volcanic plumes. Since the concentrations of hydrogen halides are not directly accesable by remote sensing techniques, an in situ method with coated gas diffusion denuder was developed. The method uses selective derivatization reaction of gaseous hydrogen halides with an organic compound for the enrichment and immobilization. For this task 5,6-Epoxy-5,6-dihydro-1,10-phenanthrolin was identified as a suitable

  1. Design and construction of mound breakwaters

    Directory of Open Access Journals (Sweden)

    Josep R. Medina

    2014-08-01

    Full Text Available This paper describes the evolution of design techniques applied to mound breakwaters as well as some key tools, equipment and construction techniques. The influence of the theoretical and laboratory research is analyzed in detail, from the pioneering research by Iribarren eighty years ago to the construction of single-layer armored breakwaters in recent decades. The economic optimization and the new embodied energy and carbon concepts associated to the construction of mound breakwaters are studied. New concepts as well as the invention of new armor units are examined as is their impact based on the observations from small-scale physical experiments and the relevance of the equipment and logistic constraints to explain the evolution of the way mound breakwaters have been designed and built over time.

  2. VolcLab: A balloon-borne instrument package to measure ash, gas, electrical, and turbulence properties of volcanic plumes

    Science.gov (United States)

    Airey, Martin; Harrison, Giles; Nicoll, Keri; Williams, Paul; Marlton, Graeme

    2017-04-01

    Release of volcanic ash into the atmosphere poses a significant hazard to air traffic. Exposure to appreciable concentrations (≥4 mg m-3) of ash can result in engine shutdown, air data system loss, and airframe damage, with sustained lower concentrations potentially causing other long-term detrimental effects [1]. Disruption to flights also has a societal impact. For example, the closure of European airspace following the 2010 eruption of Eyjafjallajökull resulted in global airline industry losses of order £1100 million daily and disruption to 10 million passengers. Accurate and effective measurement of the mass of ash in a volcanic plume along with in situ characterisation of other plume properties such as charge, turbulence, and SO2 concentration can be used in combination with plume dispersion modelling, remote sensing, and more sophisticated flight ban thresholds to mitigate the impact of future events. VolcLab is a disposable instrument package that may be attached to a standard commercial radiosonde, for rapid emergency deployment on a weather balloon platform. The payload includes a newly developed gravimetric sensor using the oscillating microbalance principle to measure mass directly without assumptions about particles' optical properties. The package also includes an SO2 gas detector, an optical sensor to detect ash and cloud backscatter from an LED source [2], a charge sensor to characterise electrical properties of the plume [3], and an accelerometer to measure in-plume turbulence [4]. VolcLab uses the established PANDORA interface [5], to provide data exchange and power from the radiosonde. In addition to the VolcLab measurements, the radiosonde provides standard meteorological data of temperature, pressure, and relative humidity, and GPS location. There are several benefits of using this instrument suite in this design and of using this method of deployment. Firstly, this is an all-in-one device requiring minimal expertise on the part of the end

  3. Toe rock stability for rubble mound breakwaters

    NARCIS (Netherlands)

    Baart, S.; Ebbens, R.; Nammuni-Krohn, J.; Verhagen, H.J.

    2010-01-01

    Present design tools, as found in the Rock Manual or Coastal Engineering Manual, for the determination of toe rock size for rubble mound breakwaters are based on test data with a large spread: data is relatively dispersed around the centre and descriptive equations have limited applicability ranges.

  4. EG and G Mound Applied Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Sizemore, M.S. [EG and G MAT, Miamisburg, OH (United States)

    1990-11-01

    This paper reports on the robotics applications offered by EG and G Mound Applied Technologies. The robotics/automations applications discussed include explosive remote disassembly workcell, plasma spraying robot workcell, robotic assembly of ceramic headers, pyrotechnic automation workcell, general automation projects and robotic/vision inventory. This report consists of overheads only.

  5. Characteristics of seismic waves composing Hawaiian volcanic tremor and gas-piston events observed by a near-source array

    Science.gov (United States)

    Ferrazzini, Valerie; Aki, Keiiti; Chouet, Bernard

    1991-04-01

    A correlation method, specifically designed for describing the characteristics of a complex wave field, is applied to volcanic tremor and gas-piston events recorded by a semicircular array of GEOS instruments set at the foot of the Puu Oo crater on the east rift of Kilauea volcano, Hawaii. The spatial patterns of correlation coefficients obtained as functions of frequency for the three components of motion over the entire array are similar for gas-piston events and tremor, and clearly depict dispersive waves propagating across the array from the direction of Puu Oo. The wave fields are composed of comparable amounts of Rayleigh and Love waves propagating with similar and extremely slow phase velocities ranging from 700 m/s at 2 Hz to 300 m/s at 8 Hz. The highly cracked solidified lava flow on which the array was deployed, and subjacent structure of alternating lava and ash layers formed during repeated eruptions of Puu Oo since 1983, appear to be responsible for the low velocities observed. The results from Puu Oo stand in sharp contrast to those obtained in an experiment conducted in 1976 on the partially solidified lava lake of Kilauea Iki. Rayleigh waves were not observed in Kilauea Iki, but well-developed trains of Love waves were seen to propagate there with velocities twice as high as those observed near Puu Oo. These differences in the propagation characteristics of surface waves at the two sites may be attributed to the presence of a soft horizontal layer of molten rock in Kilauea Iki, which may have lowered the phase velocity of Rayleigh waves more drastically than that of Love waves, resulting in severe scattering of the Rayleigh wave mode. On the other hand, the thin superficial pahoehoe flow under our array at Puu Oo may have favored the development of vertical columnar joints more extensively at this location than at Kilauea Iki, which may have reduced the shear moduli controlling the Love wave mode. The average phase velocities in the frequency band

  6. Independent technical review of the Mound Plant

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report documents an Independent Technical Review (ITR) of the facilities, organizations, plans, and activities required to transition particular elements of the Mound Plant from Defense Program (DP) funded operation as appropriate either to community developed reuse or safe deactivation leading to decontamination and decommissioning (D&D). The review was conducted at the request of the Dr. Willis Bixby, Deputy Assistant Secretary, U.S. Department of Energy EM-60, Office of Facility Transition and Management and is a consensus of the nine member ITR Team. Information for the review was drawn from documents provided to the ITR Team by the Miamisburg Area Office (MB) of the DOE, EG&G, the City of Miamisburg, and others; and from presentations, discussions, interviews, and facility inspections at the Mound Plant during the weeks of March 14 and March 28, 1994. During the week of April 25, 1994, the ITR Team met at Los Alamos, New Mexico to develop consensus recommendations. A presentation of the core recommendations was made at the Mound Plant on May 5, 1994. This is an independent assessment of information available to, and used by, the Mound Plant personnel. Repetition of the information is not meant to imply discovery by the ITR Team. Team members, however, acting as independent reviewers, frequently assess the information from a perspective that differs significantly from that of the Mound Plant personnel. The report is based on information obtained and conditions observed during the March 1994 review interval. The ITR process and normal site work often initiate rapid, beneficial changes in understanding and organization immediately following the review. These changes frequently alter conditions observed during the review, but the report does not address changes subsequent to the review interval.

  7. Mound site environmental report for calendar year 1991

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, L.R. [comp.] [EG and G Mound Applied Technologies, Miamisburg, OH (United States)

    1992-06-01

    Mound is a government-owned facility operated by EG&G Mound Applied Technologies for the U.S. Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE`s weapon and energy related programs, with emphasis on explosive, nuclear, and energy technology. The purpose of this report is to inform the public about the impact of Mound`s operations on the population and the environment. This report summarizes data from the Environmental Monitoring Program, through which Mound maintains continuous surveillance of radiological and nonradiological substances released from the facility.

  8. Hydraulic Response of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke

    Rubble mound breakwaters have been extensively investigated in the last decades. Nevertheless, there still exists some white spots where only little knowledge and only poor design rules are available. Some of these white spots are due to new types of structures developed in recent years...... experimental test programme with berm breakwaters, has not only resulted in an enormous amount of overtopping data, but also establishment of a design formula to calculate average overtopping discharges. Further, the test programme led to an improved design rule for front side stability of berm breakwaters......, which was not actually identifed as a white spot, but still there was room for big improvements. Rear slope stability and wave re ection has been discussed brie y. The conventional rubble mound breakwater has been investigated for many decades. Anyhow, there is still room for improvements in some areas...

  9. The Magellan mound province in the Porcupine Basin

    Science.gov (United States)

    Huvenne, V. A. I.; Bailey, W. R.; Shannon, P. M.; Naeth, J.; di Primio, R.; Henriet, J. P.; Horsfield, B.; de Haas, H.; Wheeler, A.; Olu-Le Roy, K.

    2007-02-01

    The Magellan mound province is one of the three known provinces of carbonate mounds or cold-water coral banks in the Porcupine Seabight, west of Ireland. It has been studied in detail using a large and varied data set: 2D and 3D seismic data, sidescan sonar imagery and video data collected during ROV deployment have been used to describe the mounds in terms of origin, growth processes and burial. The aim of this paper is to present the Magellan mounds and their setting in an integrated, holistic way. More than 1,000 densely spaced and mainly buried mounds have been identified in the area. They all seem to be rooted on one seismic reflection, suggesting a sudden mound start-up. Their size and spatial distribution characteristics are presented, together with the present-day appearance of the few mounds that reach the seabed. The underlying geology has been studied by means of fault analysis and numerical basin modelling in an attempt to identify possible hydrocarbon migration pathways below or in the surroundings of the Magellan mounds. Although conclusive evidence concerning the processes of mound initiation proves to be elusive, the results of both fault analysis and 2D numerical modelling failed to identify, with confidence, any direct pathways for focused hydrocarbon flow to the Magellan province. Diffuse seepage however may have taken place, as drainage area modelling suggests a possible link between mound position and structural features in the Hovland-Magellan area. During mound development and growth, the interplay of currents and sedimentation seems to have been the most important control. Mounds which could not keep pace with the sedimentation rates were buried, and on the few mounds which maintained growth, only a few corals survive at present.

  10. Mathematical models for Isoptera (Insecta mound growth

    Directory of Open Access Journals (Sweden)

    MLT. Buschini

    Full Text Available In this research we proposed two mathematical models for Isoptera mound growth derived from the Von Bertalanffy growth curve, one appropriated for Nasutitermes coxipoensis, and a more general formulation. The mean height and the mean diameter of ten small colonies were measured each month for twelve months, from April, 1995 to April, 1996. Through these data, the monthly volumes were calculated for each of them. Then the growth in height and in volume was estimated and the models proposed.

  11. Carbonate mounds from the Gulf of Cadiz in relation to methane seepage: unrelated phenomena or coupling?

    Science.gov (United States)

    Stadnitskaia, Alina; Baas, Marianne; de Haas, Henk; van Weering, Tjeerd C. E.; Kreulen, Rob R.; Sinninghe Damsté, Jaap S.

    2010-05-01

    For more than decade, the formation of carbonate mounds, related ecosystem development and organization/functioning of the entire mound habitats are subjects for a growing amount of studies and discussions. Carbonate mounds from the Gulf of Cadiz are of special interest due to their association with active mud volcanoes within the El Arraiche mud volcano field. Such co-occurrence of ecologically contrasting phenomena anticipates complex biogeochemical interactions between a carbonate mound interior and seeping through hydrocarbon-rich fluids. To get closer in understanding of how methane affects a carbonate mound development in the gulf, a combination of inorganic and organic geochemical techniques was applied to two sedimentary cores collected from summits of Alfa and Beta mounds. These mounds were found at the NW slope of the Gimini MV at the Pen Duick Mound Province. We analyzed vertical distribution profiles of sulfate, sulfide, chlorinity, DIC in combination with hydrocarbon gas measurements and lipid biomarker study. To have estimates of Sea Surface Temperature (SST) during the carbonate mound formation, we applied the TEX86 (TetraEther indeX of tetraethers with 86 carbon atoms; Schouten et al., 2002) and the alkenone-based UK37 index (Müller et al., 1998). The pore-water data revealed the presence of brine inflow, which is consistent with the data of Hensen et al., (2007). The behavior of sulfide distribution profiles and δ13C values from dissolved inorganic carbon (DIC) indicated that most of the sulfide and DIC are resulted from the microbial anaerobic oxidation of methane (AOM) processes. In contrast, the analysis of archaeal membrane lipids from distinct clades of AOM-mediating anaerobic methanotrophs showed exceedingly low concentrations of specific biomarkers, which is in contradiction with pore-water and gas chemistry data. Besides, AOM is the main cause for the increase of sedimentary alkalinity that leads to carbonate precipitation. Instead, some

  12. Environmental control on cold-water carbonate mounds development

    Science.gov (United States)

    Rüggeberg, A.; Liebetrau, V.; Raddatz, J.; Flögel, S.; Dullo, W.-Chr.; Exp. 307 Scientific Party, Iodp

    2009-04-01

    Cold-water coral reefs are very abundant along the European continental margin in intermediate water depths and are able to build up large mound structures. These carbonate mounds particularly occur in distinct mound provinces on the Irish and British continental margins. Previous investigations resulted in a better understanding of the cold-water coral ecology and the development of conceptual models to explain carbonate mound build-up. Two different hypotheses were evoked to explain the origin and development of carbonate mounds, external versus internal control (e.g., Freiwald et al. 2004 versus e.g. Hovland 1990). Several short sediment cores have been obtained from Propeller Mound, Northern Porcupine Seabight, indicating that cold-water corals grew during interglacial and warm interstadial periods of the Late Pleistocene controlled by environmental and climatic variability supporting the external control hypothesis (e.g. Dorschel et al. 2005, R

  13. Cartografical And Geodetical Aspects Of The Krakus Mound In Cracow

    Science.gov (United States)

    Banasik, Piotr

    2015-12-01

    In this work the fate of the Krakus Mound, the oldest of all existing Krakow's mounds, has been presented. The work was carried out based on selected iconographic, cartographic and geodetic documents. Using as an example old views, panoramas of the city and maps, various functions that the Krakus Mound was fulfilling over its long history were shown. An attempt was made to document the military significance of this mound and the surrounding hills. The particular astro-geodetic importance of the Krakus Mound on the scale of the city and southern Poland region was widely discussed. The Krakus Mound also inscribed itself in the history of the use of GPS technology as well as research on the local determination of the geoid in the area of Krakow.

  14. Temporal Evolution of A Carbonate Mound In The NE Atlantic

    Science.gov (United States)

    Dorschel, B.; Rüggeberg, A.; Hebbeln, D.; Dullo, C.; Freiwald, A.

    Even though carbonate mounds are quite common structures along the northeast At- lantic margin their history remains largely unknown. Besides the main question, what causes the initial development of these mounds; also their latest evolution in response to changing environmental conditions receives more and more interest. Here, this question has been tackled by new sets of stable isotope data, which provide informa- tion about the growth and accumulation pattern of these mounds for the last 100 ka. The investigated Propeller Mound (52r09'N/12r46'W) is part of the Hovland Mound Province located in the northern Porcupine Seabight. Its base is located in 800 m wa- ter depth and it expands 2 km in N-S direction and 0.7 km in E-W direction. Its top rises up to 150 m above the surrounding seafloor. In September 2000 eight gravity cores have been collected from the Propeller Mound and the surrounding area. Four cores taken from the mound contain cold-water corals and coral fragments in a matrix of silt and clay. The other cores collected from a moat around the mound and from a drift body in the northeast contain mainly sandy silty clays. All off-mound cores are easy to correlate using proxies like Ca ore Fe content. Inter-core correlations with on- mound cores turned out to be difficult. Fragments of the cold-water corals Lophelia pertusa and Madrepora occulata overprint the hemipelagic background signal. Here we use stable isotope data from benthic foraminifers for an inter-core correlation. In combination with 14C ages these data provide information about the evolutionof the mounds in relation to the off-mound area with respect to climate variations during the last 100 ka.

  15. Mound site environmental report for calendar year 1992

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, L.R.

    1993-07-01

    The purpose of this report is to inform the public about the impact of Mound operations on the population and the environment. Mound is a government-owned facility operated by EG&G Mound Applied Technologies for the US Department of Energy (DOE). This integrated production, development, and research site performs work in support of DOE`s weapon and energy related programs, with emphasis on explosive, nuclear and energy technologies.

  16. Catastrophic volcanism

    Science.gov (United States)

    Lipman, Peter W.

    1988-01-01

    Since primitive times, catastrophes due to volcanic activity have been vivid in the mind of man, who knew that his activities in many parts of the world were threatened by lava flows, mudflows, and ash falls. Within the present century, increasingly complex interactions between volcanism and the environment, on scales not previously experienced historically, have been detected or suspected from geologic observations. These include enormous hot pyroclastic flows associated with collapse at source calderas and fed by eruption columns that reached the stratosphere, relations between huge flood basalt eruptions at hotspots and the rifting of continents, devastating laterally-directed volcanic blasts and pyroclastic surges, great volcanic-generated tsunamis, climate modification from volcanic release of ash and sulfur aerosols into the upper atmosphere, modification of ocean circulation by volcanic constructs and attendent climatic implications, global pulsations in intensity of volcanic activity, and perhaps triggering of some intense terrestrial volcanism by planetary impacts. Complex feedback between volcanic activity and additional seemingly unrelated terrestrial processes likely remains unrecognized. Only recently has it become possible to begin to evaluate the degree to which such large-scale volcanic processes may have been important in triggering or modulating the tempo of faunal extinctions and other evolutionary events. In this overview, such processes are examined from the viewpoint of a field volcanologist, rather than as a previous participant in controversies concerning the interrelations between extinctions, impacts, and volcanism.

  17. Numerical modelling of gas-water-rock interactions in volcanic-hydrothermal environment: the Ischia Island (Southern Italy) case study.

    Science.gov (United States)

    Di Napoli, R.; Federico, C.; Aiuppa, A.; D'Antonio, M.; Valenza, M.

    2012-04-01

    Hydrothermal systems hosted within active volcanic systems represent an excellent opportunity to investigate the interactions between aquifer rocks, infiltrating waters and deep-rising magmatic fluids, and thus allow deriving information on the activity state of dormant volcanoes. From a thermodynamic perspective, gas-water-rock interaction processes are normally far from equilibrium, but can be represented by an array of chemical reactions, in which irreversible mass transfer occurs from host rock minerals to leaching solutions, and then to secondary hydrothermal minerals. While initially developed to investigate interactions in near-surface groundwater environments, the reaction path modeling approach of Helgeson and co-workers can also be applied to quantitative investigation of reactions in high T-P environments. Ischia volcano, being the site of diffuse hydrothermal circulation, is an ideal place where to test the application of reaction-path modeling. Since its last eruption in 1302 AD, Ischia has shown a variety of hydrothermal features, including fumarolic emissions, diffuse soil degassing and hot waters discharges. These are the superficial manifestation of an intense hydrothermal circulation at depth. A recent work has shown the existence of several superposed aquifers; the shallowest (near to boiling) feeds the numerous surface thermal discharges, and is recharged by both superficial waters and deeper and hotter (150-260°C) hydrothermal reservoir fluids. Here, we use reaction path modelling (performed by using the code EQ3/6) to quantitatively constrain the compositional evolution of Ischia thermal fluids during their hydrothermal flow. Simulations suggest that compositions of Ischia groundwaters are buffered by interactions between reservoir rocks and recharge waters (meteoric fluids variably mixed - from 2 to 80% - with seawater) at shallow aquifer conditions. A CO2 rich gaseous phase is also involved in the interaction processes (fCO2 = 0.4-0.6 bar

  18. Gas Geochemistry of Volcanic and Geothermal Areas in the Kenya Rift: Implications for the Role of Fluids in Continental Rifting

    Science.gov (United States)

    Lee, H.; Fischer, T. P.; Ranka, L. S.; Onguso, B.; Kanda, I.; Opiyo-Akech, N.; Sharp, Z. D.; Hilton, D. R.; Kattenhorn, S. A.; Muirhead, J.

    2013-12-01

    The East African Rift (EAR) is an active continental rift and ideal to investigate the processes of rift initiation and the breaking apart of continental lithosphere. Mantle and crust-derived fluids may play a pivotal role in both magmatism and faulting in the EAR. For instance, large quantities of mantle-derived volatiles are emitted at Oldoinyo Lengai volcano [1, 2]. Throughout the EAR, CO2-dominated volatile fluxes are prevalent [3, 4] and often associated with faults (i.e. Rungwe area, Tanzania, [5, 6]). The purpose of this study is to examine the relationship between volcanism, faulting and the volatile compositions, focusing on the central and southern Kenyan and northern Tanzanian section of the EAR. We report our analysis results for samples obtained during a 2013 field season in Kenya. Gases were sampled at fumaroles and geothermal plants in caldera volcanoes (T=83.1-120.2°C) and springs (T=40-79.6°C and pH 8.5-10) located near volcanoes, intra-rift faults, and a transverse fault (the Kordjya fault, a key fluid source in the Magadi rift) by 4N-NaOH solution-filled and empty Giggenbach bottles. Headspace gases were analyzed by a Gas Chromatograph and a Quadrupole Mass Spectrometer at the University of New Mexico. Both N2/Ar and N2/He ratios of all gases (35.38-205.31 and 142.92-564,272, respectively) range between air saturated water (ASW, 40 and ≥150,000) and MORB (100-200 and 40-50). In addition, an N2-Ar-He ternary diagram supports that the gases are produced by two component (mantle and air) mixing. Gases in the empty bottles from volcanoes and springs have N2 (90.88-895.99 mmom/mol), CO2 (2.47-681.21 mmom/mol), CH4 (0-214.78 mmom/mol), O2 (4.47-131.12 mmom/mol), H2 (0-35.78 mmom/mol), Ar (0.15-10.65 mmom/mol), He (0-2.21 mmom/mol), and CO (0-0.08 mmom/mol). Although some of the samples show an atmospheric component, CO2 is a major component in most samples, indicating both volcanoes and springs are emitting CO2. Gases from volcanoes are enriched in

  19. Chapter 1: Executive Summary - 2003 Assessment of Undiscovered Oil and Gas Resources in the Upper Cretaceous Navarro and Taylor Groups, Western Gulf Province, Gulf Coast Region, Texas

    Science.gov (United States)

    ,

    2006-01-01

    The U.S. Geological Survey (USGS) recently completed an assessment of the undiscovered oil and gas potential of the Upper Cretaceous Navarro and Taylor Groups in the Western Gulf Province of the Gulf Coast region (fig. 1) as part of a national oil and gas assessment effort (USGS Navarro and Taylor Groups Assessment Team, 2004). The assessment of the petroleum potential of the Navarro and Taylor Groups was based on the general geologic elements used to define a total petroleum system (TPS), including hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). Using this geologic framework, the USGS defined five assessment units (AU) in the Navarro and Taylor Groups as parts of a single TPS, the Smackover-Austin-Eagle Ford Composite TPS: Travis Volcanic Mounds Oil AU, Uvalde Volcanic Mounds Gas and Oil AU, Navarro-Taylor Updip Oil and Gas AU, Navarro-Taylor Downdip Gas and Oil AU, and Navarro-Taylor Slope-Basin Gas AU (table 1).

  20. Mitigating the consequences of extreme events on strategic facilities: evaluation of volcanic and seismic risk affecting the Caspian oil and gas pipelines in the Republic of Georgia.

    Science.gov (United States)

    Pasquarè, F A; Tormey, D; Vezzoli, L; Okrostsvaridze, A; Tutberidze, B

    2011-07-01

    In this work we identify and quantify new seismic and volcanic risks threatening the strategic Caspian oil and gas pipelines through the Republic of Georgia, in the vicinity of the recent Abuli Samsari Volcanic Ridge, and evaluate risk reduction measures, mitigation measures, and monitoring. As regards seismic risk, we identified a major, NW-SE trending strike-slip fault; based on the analysis of fault planes along this major transcurrent structure, an about N-S trend of the maximum, horizontal compressive stress (σ1) was determined, which is in good agreement with data instrumentally derived after the 1986, M 5.6 Paravani earthquake and its aftershock. Particularly notable is the strong alignment of volcanic vents along an about N-S trend that suggests a magma rising controlled by the about N-S-directed σ1. The original pipeline design included mitigation measures for seismic risk and other geohazards, including burial of the pipeline for its entire length, increased wall thickness, block valve spacing near recognized hazards, and monitoring of known landslide hazards. However, the design did not consider volcanic risk or the specific seismic hazards revealed by this study. The result of our analysis is that the Baku-Tbilisi-Ceyhan (BTC) oil pipeline, as well as the Baku-Tbilisi-Erzerum South Caucasian natural gas pipeline (SCP) were designed in such a way that they significantly reduce the risk posed by the newly-identified geohazards in the vicinity of the Abuli-Samsari Ridge. No new measures are recommended for the pipeline itself as a result of this study. However, since the consequences of long-term shut-down would be very damaging to the economies of Western Europe, we conclude that the regionally significant BTC and SCP warrant greater protections, described in the final section of or work. The overall objective of our effort is to present the results in a matrix framework that allows the technical information to be used further in the decision

  1. Hydraulic Response of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke

    , which was not actually identifed as a white spot, but still there was room for big improvements. Rear slope stability and wave re ection has been discussed brie y. The conventional rubble mound breakwater has been investigated for many decades. Anyhow, there is still room for improvements in some areas...... experimental test programme with berm breakwaters, has not only resulted in an enormous amount of overtopping data, but also establishment of a design formula to calculate average overtopping discharges. Further, the test programme led to an improved design rule for front side stability of berm breakwaters...

  2. Calculation of multicomponent chemical equilibria in gas-solid- liquid systems: calculation methods, thermochemical data, and applications to studies of high-temperature volcanic gases with examples from Mount St. Helens

    Science.gov (United States)

    Symonds, R.B.; Reed, M.H.

    1993-01-01

    This paper documents the numerical formulations, thermochemical data base, and possible applications of computer programs, SOLVGAS and GASWORKS, for calculating multicomponent chemical equilibria in gas-solid-liquid systems. SOLVGAS and GASWORKS compute simultaneous equilibria by solving simultaneously a set of mass balance and mass action equations written for all gas species and for all gas-solid or gas-liquid equilibria. Examples of gas-evaporation-from-magma and precipitation-with-cooling calculations for volcanic gases collected from Mount St. Helens are shown. -from Authors

  3. Stability Of Rubble Mound Breakwaters Using High Density Rock

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Beck, J. B.

    2000-01-01

    The present paper discusses the effect of mass density on stability of rubble mound breakwaters. A short literature review of existing knowledge is give to establish a background for the ongoing research. Furthermore, several model tests are described in which the stability of rubble mound breakw...

  4. 火山岩气藏水平井水平段合理长度确定%DETERMINATION OF HORIZONTAL SECTION LENGTH OF HORIZONTAL WELL IN VOLCANIC GAS RESERVOIR

    Institute of Scientific and Technical Information of China (English)

    曹宝军

    2011-01-01

    水平段长度不仅影响水平井单井产量,还影响水平井钻井投资.火山岩气藏水平井钻井成本相对较高,因此确定水平井段的合理长度对火山岩气藏水平井开发设计非常重要.在徐深气田火山岩气藏水平井开发先导性试验中,考虑井筒摩擦阻力,根据水平井简内的流体流动和气藏内流体渗流的耦合,从经济效益的角度提出了火山岩气藏水平井水平井段合理长度的确定方法,对火山岩气藏水平井设计具有重要的指导意义.%The length of horizontal section of a horizontal well affects not only the single well production rate, but also the drilling investment of a horizontal well. Considering the relatively high drilling cost of horizontal well in volcanic gas reservoir, it is significant to determine the rational length of horizontal section in horizontal well for volcanic gas reservoir development. In the horizontal development pilot experiment of volcanic gas reservoir in Xushen gas field, taking frictional resistance of wellbore into consideration and according to the coupling between the fluids flowing in the wellbore and seepage of fluids in the gas reservoir, a determination method of the horizontal section of horizontal well in volcanic gas reservoir is proposed in view of economic effect, which provides guide for horizontal well design in volcanic gas reservoirs.

  5. Volcanic eruptions observed with infrasound

    Science.gov (United States)

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.

    2004-07-01

    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  6. 火山岩气藏早期开发特征及其控制因素%Early-stage development characteristics of volcanic gas reservoirs and its controlling factors

    Institute of Scientific and Technical Information of China (English)

    庞彦明; 毕晓明; 邵锐; 邱红枫

    2009-01-01

    通过大庆徐深气田开发取得的矿场资料,分析了火山岩储层开发动态特征,并论述其产生的控制因素.火山岩气藏表现为气井产能、动态储量井与井差异大.试井曲线反映储层具有多种流动区域形态.单井的产量与地层系数、压裂规模关系复杂,即气井产量与压裂规模关系不能用基本的压裂改造机理描述,压裂的增产机理主要是沟通作用,而改造作用次之.研究结果表明,产生其开发动态特殊性的主要控制因素是火山岩储层具有不同于层状储层的储层分布宏观非均质性和具有不同于常规储层的储层微观孔隙结构复杂性.%Based on the field development data of Xushen Gas Field in Daqing area, the special development performances of volcanic gas reservoirs were investigated. The analysis on the controlling factors of the volcanic gas reservoirs demonstrated that the gas pro-ductivity and dynamic reserve volume of gas wells in the volcanic gas reservoirs were greatly different. There are many flow regime patterns in the well-testing curves of volcanic formations. The gas productivity of single well has a complex relationship with reser-voir capacity and fracturing scale, which could not be expressed by the primary fracturing concept. The main fracturing mechanism to the volcanic reservoir is channeling, and then is reformation. The main factors for controlling the special performance of volcanic reservoir include the volcanic layer macroscopic heterogeneity different from the layer reservoir and the microscopic pore structure different from the conventional reservoir.

  7. Numerical investigation of temporal changes in volcanic deformation caused by a gas slug ascent in the conduit

    Science.gov (United States)

    Kawaguchi, Ryohei; Nishimura, Takeshi

    2015-09-01

    Strombolian type eruptions are considered to be generated by a sudden release of a large gas slug that migrates upward in the conduit filled with a low viscous basaltic magma. We examine volcano deformations caused by such a gas slug to understand the Strombolian eruption mechanism from geodetic observation data. We model spatio-temporal pressure changes in the conduit by using a gas slug ascent model presented by James et al. (2008). As a gas slug ascends in the conduit, its volume expands because of depressurization. Hence, the magma head lifts up in the conduit and the upper part of the conduit wall is stressed. In the conduit, magma pressure increases with depth according to the bulk density of magma: the gas slug part with a low density is characterized by a small pressure gradient, while the other parts, consisting of melt, are characterized by a large pressure gradient. We numerically calculate volcano deformations caused by the spatio-temporal changes of magma pressure predicted from the basic equations representing gas slug locations in the conduit. Simulation results show that the radial and vertical displacements and tilt changes indicate volcano deformations that represent the inflation originating from the stress increase at the upper part of conduit. As the gas slug reaches the shallow part of conduit, the rate of inflation observed in the radial displacement decreases, the vertical displacement starts to move downward, and the tilt turns to show down toward the crater. These deflation signals are caused by a moving deflation source in the conduit that is formed beneath the gas slug. Since these predicted features are not observed in the tilt records associated with explosions at Stromboli volcano (Genco and Ripepe, 2010), it is necessary to modify the gas slug ascent model or to introduce other mechanisms to better understand the magma dynamics of Strombolian eruption.

  8. Biotic origin for Mima mounds supported by numerical modeling

    Science.gov (United States)

    Gabet, Emmanuel J.; Perron, J. Taylor; Johnson, Donald L.

    2014-02-01

    Mima mounds are ~ 1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by nonhuman mammals and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.

  9. Biotic Origin for Mima Mounds Supported by Numerical Model

    Science.gov (United States)

    Gabet, E. J.; Perron, J.; Johnson, D. L.

    2013-12-01

    Mima mounds are ~1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds, as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by non-human mammals, and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.

  10. Benthic foraminiferal assemblages help to understand carbonate mound evolution

    Science.gov (United States)

    Rüggeberg, A.; Dorschel, B.; Dullo, C.; Hebbeln, D.; Freiwald, A.

    2003-04-01

    On- and off-mound sediment cores from Propeller Mound (Porcupine Seabight) were analysed for their benthic foraminiferal assemblages. Benthic foraminifera from the off-mound position show three different assemblages describing the Holocene, Oxygen Isotope Stage (OIS) 2 and late OIS 3. The Holocene assemblage is dominated by Uvigerina mediterranea, Trifarina angulosa, Melonis barleeanum, Hyalinea balthica, Bulimina marginata. These species are related to a higher supply of organic material. The glacial assemblage shows high abundances of Cassidulina teretis, C. reniforme, Globocassidulina subglobosa, and Cibicidoides kullenbergi, implying cold bottom waters and a reduced productivity. The lower part of late OIS 3 is dominated by Elphidium excavatum, which is displaced continuously by very high abundances of C. teretis towards the transition of OIS3/2. E. excavatum, a shallow shelf species generally reported from above 200 m water depth, and high amounts of sediment supplied to the core site points to shelf erosion related to sea level lowering (approx. 50 m). Towards OIS 2 the system returns to normal background sedimentation pattern. We transferred the established off-mound assemblages onto the on-mound core, in which the sediment sequence is incomplete characterised by numerous hiatuses. The Holocene assemblage describes almost the complete core with relative abundances of >20%, interrupted only by three sections with slightly higher amounts of the glacial assemblage, which are not comparable to abundances of >70% of the glacial assemblage found in the off-mound core. These results are in conjunction with stable oxygen isotope data indicating only interstadial values, assuming peak glacial and interglacial sediments to be removed from the mound. Another assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species

  11. Biodiversity and ecological composition of macrobenthos on cold-water coral mounds and adjacent off-mound habitat in the bathyal Porcupine Seabight, NE Atlantic

    Science.gov (United States)

    Henry, Lea-Anne; Roberts, J. Murray

    2007-04-01

    The cold-water scleractinian corals Lophelia pertusa and Madrepora oculata form mound structures on the continental shelf and slope in the NE Atlantic. This study is the first to compare the taxonomic biodiversity and ecological composition of the macrobenthos between on- and off-mound habitats. Seven box cores from the summits of three mounds and four cores from an adjacent off-mound area in the Belgica Mound Province in the Porcupine Seabight yielded 349 species, including 10 undescribed species. On-mound habitat was three times more speciose, and was richer with higher evenness and significantly greater Shannon's diversity than off-mound. Species composition differed significantly between habitats and the four best discriminating species were Pliobothrus symmetricus (more frequent off-mound), Crisia nov. sp, Aphrocallistes bocagei and Lophelia pertusa (all more frequent on-mound). Filter/suspension feeders were significantly more abundant on-mound, while deposit feeders were significantly more abundant off-mound. Species composition did not significantly differ between mounds, but similarity within replicates decreased from Galway MoundMound. We propose that, despite having greater vertical habitat heterogeneity that supports higher biodiversity, coral mounds have a characteristic "reef fauna" linked to species' biology that contrasts with the higher horizontal habitat heterogeneity conferred by the action of deposit feeders and a varied seabed sedimentary facies off-mound. Standardisation of equipment and restriction of analyses to higher taxonomic levels would facilitate prospective comparative analyses of cold-water coral biodiversity across larger spatio-temporal scales.

  12. Audit of Mound Plant`s reduction in force

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-17

    Objective of this audit was to determine whether the Mound Plant`s Fiscal Year 1992 reduction in force (RIF) was effectively managed and implemented properly by DOE. DOE established policy to encourage contractors to reduce staffing by voluntary separations without unreasonable separation costs. EG&G Mound`s FY 1992 RIF was accomplished by voluntary separations; however, its implementation unreasonably increased costs because DOE did not have adequate criteria or guidelines for evaluating contractors` RIF proposals, and because EG&G Mound furnished inaccurate cost data to DOE evaluators. The unreasonable costs amounted to at least $21 million. Recommendations are made that DOE develop and implement guidelines to impose limitations on voluntary separation allowances, early retirement incentive payments, and inclusion of crucial employee classifications in voluntary RIFs.

  13. 松南气田火山岩气藏产水特征和控水策略%Water production characteristics and control strategy of volcanic reservoir in Songnan gas field

    Institute of Scientific and Technical Information of China (English)

    常文博; 任宪军; 单玄龙

    2016-01-01

    基于天然气单次闪蒸实验、气藏水化验分析两种方法,区分松辽盆地松南气田气井产水类型;结合气藏精细描述,分析不同气井的产水机理;进一步利用数值模拟,探索火山岩气藏控水策略。松南气田产水可分为凝析水和地层水两种类型,构造高部位火山机构气井产凝析水,构造低部位火山机构气井产地层水。断层引起的底水上窜是造成构造高部位钻井产少量地层水的主要原因。通过数值模拟发现,采气速度越高,边底水锥进越快。松南气田火山岩气藏最优采气速度约在3.6%。根据高部位高配、低部位低配的控水原则,明确了不同类型、不同构造部位火山岩气井合理产量,可有效控制火山岩气井出水,实现气藏稳产。%Based on the gas single flash experiment and gas reservoir water chemical examination,the types of water production of Songnan gas field in Songliao Basin were determined.Combined with fine description of volcan-ic reservoirs,the different water production mechanisms were analyzed.Furthermore,the authors explored the wa-ter control strategy based on numerical simulation.The water production in Songnan gas filed can be divided into two types:condensate water and formation water.The gas wells which drilled the high volcanic edifice produce condensate water,while drilled the low volcanic edifice produce formation water.The bottom water coning along the fault is the primary cause of formation water output from some gas wells drilled the high volcanic edifice.The nu-merical simulation indicated that there is a positive correlation between gas recovery rate and bottom water coning rate.The optimal gas recovery rate in Songnan volcanic gas field is about 3. 6%.According to the water control principle of high production at high structural position and low production at low structural position,the authors cal-culate the reasonable production of volcanic gas

  14. Environmental assessment for commercialization of the Mound Plant

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-26

    In November 1993 US DOE decided to phase out operations at the Mound Plant in Miamisburg, Ohio, with the goal of releasing the site for commercial use. The broad concept is to transform the plant into an advanced manufacturing center with the main focus on commercializing products and other technology. DOE proposes to lease portions of the Mound Plant to commercial enterprises. This Environmental Impact statement has a finding of no significant impact in reference to such action.

  15. Ireland's deep-water coral carbonate mounds: multidisciplinary research results

    Science.gov (United States)

    Kozachenko, M.; Wheeler, A.; Beyer, A.; Blamart, D.; Masson, D.; Olu-Le Roy, K.

    2003-04-01

    Recent international research activity, involving a strong Irish collaboration, has shown that coral reefs are not exclusively associated with warm tropical waters but are also present in the deeper and colder Northeast Atlantic. In the Porcupine Seabight west of Ireland, coral-colonised carbonate mounds (up to 350m high) are present at 600-900m water depth. The corals Lophelia pertusa L. and Madrepora oculata L. contribute to this diverse ecosystem that may also play a significant role in expanding deep-water fisheries. New side-scan sonar, multibeam echosounder, sub-bottom profiler and underwater video imagery supplemented with sedimentological sample material were used to map the seabed in the environs of the Belgica Carbonate Mound province, eastern Porcupine Seabight. The data were integrated in a GIS and provides information on sediment pathways and benthic current patterns within the study area. A facies map of the study area highlights differing sedimentary processes showing evidences for strong northward bottom currents whose interaction has an influence on mounds growth and morphology. This survey revealed mound flanks dominated by sediment waves that give way to coral banks towards the mound summits. A form of coral accumulation was also documented. Detailed analyses of sediment properties from long cores through sediment drifts have generated a high-resolution palaeoclimate record revealing temporal patterns in bottom current strength variations. An accurate assessment of this influence on mound through a comparison with coral growth rates is ongoing.

  16. Food preferences and mound-building behaviour of the mound-building mice Mus spicilegus

    Science.gov (United States)

    Hölzl, Michaela; Krištofík, Ján; Darolová, Alžbeta; Hoi, Herbert

    2011-10-01

    Optimal foraging strategies and food choice are influenced by various factors, e.g. availability, size and caloric content of the food type and predation risk. However, food choice criteria may change when food is not eaten immediately but has to be carried to a storage site for later use. For example, handling time in terms of harvesting and transport time should be optimized, particularly when the risk of predation is high. Thus, it is not clear whether food selected by hoarding animals reflects their food preference due to intrinsic features of the food type, e.g. size, caloric or lipid content, or whether the food type selected is a compromise that also considers the handling time required for harvesting and transport. We investigate this question in relation to food hoarding behaviour in mound-building mice. In autumn, mound-building mice Mus spicilegus collect seeds and other plant material and cover it with soil. Such above-ground storage is quite unusual for rodents. Here, we investigated whether there is a relationship between the seed species preferred as building materials and those preferred for food. We conducted a seed preference test using three most collected weed species for mound building. Controlling factors like food availability or predation risk, mice prefer Setaria spp. as food, although Amaranthus spp. and Chenopodium spp. were preferentially harvested and stored. By including the availability of the three species, our experimental results were confirmed, namely, a clear preference for Setaria spp. Also, handling time and seed size revealed to influence plant choice.

  17. Efficient Exploration and Development of Carboniferous Volcanic Gas Field in Kelameili Area in Junggar Basin%克拉美丽石炭系火山岩气田的高效勘探开发

    Institute of Scientific and Technical Information of China (English)

    董雪梅; 徐怀民; 贺陆明; 任军民; 吴静

    2012-01-01

    Volcanic oil-gas exploration in Junggar basin started in 1950's.In recent years,through comprehensive researches of hydrocarbon accumulation conditions of the Carboniferous volcanic reservoirs,Ludong-Wucaiwan area is chosen as major exploration target to carry out systematic studies and make technological breakthrough,thus deepening the knowledge of volcanic reservoir,establishing the exploration thought of reservoir controls dominated by volcanic rock body,based on which the matched technologies were developed,and the breakthroughs have been made in drilling of volcanic rock body as main target in Dinan bulge.A hundred billion cubic meters of Kelameili gas field with both source and reservoir in Carboniferous system was proved in two years and the first large-scale integrated volcanic gas field in Junggar basin is discovered.Up to now,it has been brought into the scale and efficient production.The Carboniferous volcanic reservoirs have become an important domain for oil-gas exploration in Junggar basin.%准噶尔盆地火山岩油气勘探始于20世纪50年代,近年来通过准噶尔盆地石炭系油气成藏条件综合研究,优选陆东—五彩湾地区作为勘探主战场,展开针对石炭系火山岩的系统研究和技术攻关,不断深化成藏认识,确立了以火山岩岩体控藏的勘探思路,研发了与之相应的配套技术,在滴南凸起上以火山岩岩体为主要目标展开钻探获得突破,探明了千亿方的石炭系自生自储的克拉美丽气田,形成准噶尔盆地第一个大型整装火山岩气田,并已实现规模高效开发。石炭系火山岩已经成为准噶尔盆地油气勘探的重要领域。

  18. Hydrodynamic Conditions Influencing Cold-Water Coral Carbonate Mound Development (Challenger Mound, Porcupine Seabight, NE Atlantic): a Contribution to IODP Exp307

    Science.gov (United States)

    Thierens, M.; Odonnell, R.; Stuut, J.; Titschack, J.; Dorschel, B.; Wheeler, A. J.

    2007-12-01

    Cold-water coral carbonate mounds are complex geo-biological systems, originating from the interplay of hydrodynamic, sedimentological and biological factors. As changes in hydrodynamic and sedimentary regime are assumed to be amongst the main controls on mound evolution, reconstruction of the hydrodynamic and palaeoclimatic microenvironment on-mound, compared to the background environmental conditions (as seen off- mound), contributes to the fundamental understanding of these intriguing features and the development of a cold- water coral carbonate mound development model. Challenger Mound, one of the large cold-water coral carbonate mounds along the eastern Porcupine Seabight continental margin (NE Atlantic, SW off Ireland), was successfully drilled during IODP Expedition 307, providing the first complete recovery of a continuous sedimentary sequence through a carbonate mound. High-resolution particle size analysis of the terrigenous sediment component is used as primary proxy for reconstructing the hydrodynamic conditions during mound development. First results indicate repeated shifts in hydrodynamic conditions during sediment deposition on Challenger Mound, from lower-energetic conditions to higher-energetic environments and visa versa, which might reflect environmental variation over interglacial-glacial timescales throughout the whole mound development period. In conjunction with other available data, this dataset provides insight in local current regimes and sediment dynamics, the specific role of cold-water corals in these complex geo-biological systems and the differentiation of different sediment contributors to the coral mound system and its surroundings.

  19. From Shell Midden to Midden-Mound: The Geoarchaeology of Mound Key, an Anthropogenic Island in Southwest Florida, USA.

    Directory of Open Access Journals (Sweden)

    Victor D Thompson

    Full Text Available Mound Key was once the capital of the Calusa Kingdom, a large Pre-Hispanic polity that controlled much of southern Florida. Mound Key, like other archaeological sites along the southwest Gulf Coast, is a large expanse of shell and other anthropogenic sediments. The challenges that these sites pose are largely due to the size and areal extent of the deposits, some of which begin up to a meter below and exceed nine meters above modern sea levels. Additionally, the complex depositional sequences at these sites present difficulties in determining their chronology. Here, we examine the development of Mound Key as an anthropogenic island through systematic coring of the deposits, excavations, and intensive radiocarbon dating. The resulting data, which include the reversals of radiocarbon dates from cores and dates from mound-top features, lend insight into the temporality of site formation. We use these insights to discuss the nature and scale of human activities that worked to form this large island in the context of its dynamic, environmental setting. We present the case that deposits within Mound Key's central area accumulated through complex processes that represent a diversity of human action including midden accumulation and the redeposition of older sediments as mound fill.

  20. Volcanic hazards to airports

    Science.gov (United States)

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

    2009-01-01

    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  1. Diffuse volcanic gas emission and thermal energy release from the summit crater of Pico do Fogo, Cape Verde

    Science.gov (United States)

    Dionis, Samara M.; Melián, Gladys; Rodríguez, Fátima; Hernández, Pedro A.; Padrón, Eleazar; Pérez, Nemesio M.; Barrancos, Jose; Padilla, Germán; Sumino, Hirochika; Fernandes, Paulo; Bandomo, Zuleyka; Silva, Sónia; Pereira, José M.; Semedo, Hélio

    2015-02-01

    We report the first detailed study of diffuse emission of carbon dioxide (CO2), hydrogen sulfide (H2S), helium (He), and hydrogen (H2) from the summit crater of Pico do Fogo volcano, Cape Verde. Diffuse CO2, H2S, He, and H2 gas fluxes were measured at 57 sampling sites and ranged up to 12,800, 13, 1, and 6 g m-2 day-1, respectively. Soil temperature measurements at each sampling site were used to evaluate the heat flux. Most of the summit crater shows relatively high CO2 efflux, with highest values close to the fumarolic area, suggesting a structural control of the degassing process. In contrast, H2S effluxes were negligible or very low at the summit crater, except close to the fumarolic area where anomalously high CO2 efflux and soil temperatures were also measured. We estimate total CO2, H2S, He, and H2 diffuse gas fluxes of 219 t day-1, 25, 4, and 33 kg day-1, respectively. Based on a H2O/CO2 mass ratio of 1.52 measured at the fumaroles, we estimate a diffuse steam flux from the summit crater of approximately 330 t day-1. The enthalpy of this steam is equivalent to a heat flux of about 10.3 MW. The diffuse gas emission and thermal energy released from the summit crater of Pico do Fogo volcano are comparable to those observed at other volcanoes. Sustained surveillance of Pico do Fogo using these methods will be valuable for monitoring the activity of one of the most active volcanoes in the Atlantic Ocean.

  2. Pre-eruptive volatile and erupted gas phase characterization of the 2014 basalt of Bárðarbunga volcanic system, Iceland.

    Science.gov (United States)

    Haddadi, Baptiste; Moune, Séverine; Sigmarsson, Olgeir; Gauthier, Pierre-Jean; Gouhier, Mathieu

    2015-04-01

    The 2014 Holuhraun eruption on the Bárðarbunga Volcanic System is the largest fissure eruption in Iceland since the 1783 Laki eruption. The eruption started end of August 2014 and has been characterized by large emission of SO2 into the atmosphere. It provides a rare opportunity to study in details magmatic and degassing processes during a large-volume fissure eruption. In order to characterize the pre-eruptive magmatic composition and to assess the plume chemistry at the eruption site, lava and tephra were sampled together with the eruption plume. The basalt composition is olivine tholeiite with MgO close to 7 wt%. It is phenocryst-poor with plagioclase as the dominant mineral phase but olivine and clinopyroxene are also present together with sulphide globules composed principally of pyrite and chalcopyrite. The volatile (S, Cl and F) and major element concentrations were measured by the electron microprobe in melt inclusions (MIs) trapped in plagioclase and clinopyroxene and groundmass glass. The MIs composition ranges from fairly primitive basaltic compositions (MgO: 9.03 wt%) down to evolved qz-tholeiites (MgO: 5.57 wt%), with estimated pre-eruptive S concentrations of 1500 ppm. Tephra groundmass glass contains 400 ppm S, whereas Cl and F concentrations are respectively slightly lower and indistinguishable from those in the MIs. This implies limited exsolution of halogens but 75% of the initial sulphur content. Relatively to their total iron content, MIs are sulphur saturated, and their oxygen fugacity close to the FMQ buffer. The difference between the estimated initial volatile concentrations measured in the MIs and in the tephra groundmass (i.e. the so-called petrological method) yields 7.2 Mt SO2, limited HCl and no HF atmospheric mass loading from the Holuhraun 2014 eruption. The SO2/HCl molar ratio of the gas phase, calculated from the MIs, is 13 and 14, respectively, using average and estimated pre-eruptive S and Cl concentrations in the MIs. Filter

  3. Cold-water coral carbonate mounds as unique palaeo-archives: the Plio-Pleistocene Challenger Mound record (NE Atlantic)

    Science.gov (United States)

    Thierens, M.; Browning, E.; Pirlet, H.; Loutre, M.-F.; Dorschel, B.; Huvenne, V. A. I.; Titschack, J.; Colin, C.; Foubert, A.; Wheeler, A. J.

    2013-08-01

    Through the interplay of a stabilising cold-water coral framework and a dynamic sedimentary environment, cold-water coral carbonate mounds create distinctive centres of bio-geological accumulation in often complex (continental margin) settings. The IODP Expedition 307 drilling of the Challenger Mound (eastern Porcupine Seabight; NE Atlantic) not only retrieved the first complete developmental history of a coral carbonate mound, it also exposed a unique, Early-Pleistocene sedimentary sequence of exceptional resolution along the mid-latitudinal NE Atlantic margin. In this study, a comprehensive assessment of the Challenger Mound as an archive of Quaternary palaeo-environmental change and long-term coral carbonate mound development is presented. New and existing environmental proxy records, including clay mineralogy, planktonic foraminifer and calcareous nannofossil biostratigraphy and assemblage counts, planktonic foraminifer oxygen isotopes and siliciclastic particle-size, are thereby discussed within a refined chronostratigraphic and climatic context. Overall, the development of the Challenger Mound shows a strong affinity to the Plio-Pleistocene evolution of the Northern Hemisphere climate system, albeit not being completely in phase with it. The two major oceanographic and climatic transitions of the Plio-Pleistocene - the Late Pliocene/Early Pleistocene intensification of continental ice-sheet development and the mid-Pleistocene transition to the more extremely variable and more extensively glaciated late Quaternary - mark two major thresholds in Challenger Mound development: its Late Pliocene (>2.74 Ma) origin and its Middle-Late Pleistocene to recent decline. Distinct surface-water perturbations (i.e. water-mass/polar front migrations, productivity changes, melt-water pulses) are identified throughout the sequence, which can be linked to the intensity and extent of ice development on the nearby British-Irish Isles since the earliest Pleistocene. Glaciation

  4. HiRISE observations of fractured mounds: Possible Martian pingos

    Science.gov (United States)

    Dundas, C.M.; Mellon, M.T.; McEwen, A.S.; Lefort, A.; Keszthelyi, L.P.; Thomas, N.

    2008-01-01

    Early images from the High Resolution Imaging Science Experiment (HiRISE) camera have revealed small fractured mounds in the Martian mid-latitudes. HiRISE resolves fractures on the mound surfaces, indicating uplift, and shows that the mound surface material resembles that of the surrounding landscape. Analysis of Mars Orbiter Camera (MOC) images shows that in Utopia Planitia the mounds lie almost exclusively between 35-45??N. This range coincides with the peak-abundance latitudes of several landforms attributed to ground water or ice, including gullies, and suggests a ground ice-related origin. The best terrestrial analogues for the observed mound morphology are pingos, although some differences are noted. The presence of uncollapsed. pingos would indicate the presence of near-surface ground ice in the Martian mid-latitudes, at depths greater than the ???1 meter sampled by orbital spectrometers. Pingo formation may require near-surface liquid water, which is consistent with a shallow groundwater model for the origin of gullies. Copyright 2008 by the American Geophysical Union.

  5. Louth Crater: Evolution of a layered water ice mound

    CERN Document Server

    Brown, Adrian J; Tornabene, Livio L; Roush, Ted L

    2014-01-01

    We report on observations made of the ~36km diameter crater, Louth, in the north polar region of Mars (at 70{\\deg}N, 103.2{\\deg}E). High-resolution imagery from the instruments on the Mars Reconnaissance Orbiter (MRO) spacecraft has been used to map a 15km diameter water ice deposit in the center of the crater. The water ice mound has surface features that include roughened ice textures and layering similar to that found in the North Polar Layered Deposits. Features we interpret as sastrugi and sand dunes show consistent wind patterns within Louth over recent time. CRISM spectra of the ice mound were modeled to derive quantitative estimates of water ice and contaminant abundance, and associated ice grain size information. These morphologic and spectral results are used to propose a stratigraphy for this deposit and adjoining sand dunes. Our results suggest the edge of the water ice mound is currently in retreat.

  6. Environmental survey preliminary report, Mound Plant, Miamisburg, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    1987-03-01

    This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Mound Plant, conducted August 18 through 29, 1986. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the Mound Plant. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at the Mound Plant, and interviews with site personnel. The Survey found no environmental problems at the Mound Plant that represent an immediate threat to human life. The environmental problems identified at the Mound Plant by the Survey confirm that the site is confronted with a number of environmental problems which are by and large a legacy from past practices at a time when environmental problems were less well understood. Theses problems vary in terms of their magnitude and risk, as described in this report. Although the sampling and analysis performed by the Mound Plant Survey will assist in further identifying environmental problems at the site, a complete understanding of the significance of some of the environmental problems identified requires a level of study and characterization that is beyond the scope of the Survey. Actions currently under way or planned at the site, particularly the Phase II activities of the Comprehensive Environmental Analysis and Response Program (CEARP) as developed and implemented by the Albuquerque Operations Office, will contribute toward meeting this requirement. 85 refs., 24 figs., 20 tabs.

  7. Reconstruction of The Paleoenvironment of A Carbonate Mound In The Porcupine Seabight, West Off Ireland

    Science.gov (United States)

    Rüggeberg, A.; Dorschel, B.; Dullo, W.-Chr.

    The Propeller Mound in the Porcupine Seabight is part of a cluster of high relief carbonate mounds extending along the European continental margin from Norway to southern Ireland. During POSEIDON cruise POS265 in September 2000 this mound was surveyed and several sediment cores with core lengths of up to 5.90 m were retrieved, located on-mound and off-mound positions. Investigations of these cores are concentrated on faunal assemblages of benthic foraminifers, grain size analysis, sortable silt, spectrophotometric data, and stable isotope and TC/TOC measurements. Forming an on-mound - off-mound transect the gravity cores will be compared in terms of temporal changes of the measured data to interpret the palaeoceanographical settings and palaeoproductivity along the Propeller Mound.

  8. Shallow water mud-mounds of the Early Devonian Buchan Group, East Gippsland, Australia

    Science.gov (United States)

    Tosolini, A.-M. P.; Wallace, M. W.; Gallagher, S. J.

    2012-12-01

    The Lower Devonian Rocky Camp Member of the Murrindal Limestone, Buchan Group of southeastern Australia consists of a series of carbonate mud-mounds and smaller lagoonal bioherms. The Rocky Camp mound is the best exposed of the mud-mounds and has many characteristics in common with Waulsortian (Carboniferous) mounds. Detailed paleoecological and sedimentological studies indicate that the mound initially accumulated in the photic zone, in contrast to most of the previously recorded mud-mounds. Five facies are present in the mud-mound: a Dasycladacean Wackestone Facies at the base of the mound represents a moderate energy, shallow water bank environment within the photic zone. A Crinioidal Wackestone Facies was deposited in a laterally equivalent foreslope setting. A Poriferan-Crinoidal Mudstone Facies developed in a quiet, deeper water, lee-side mound setting associated with a minor relative sea-level rise. A Stromatoporoid-Coralline Packstone Facies in the upper part of the mound deposited in a high-energy, fair-weather wave base, mound-front environment. The crest of the mound is represented by a Crinoidal-Receptaculitid Packstone Facies indicative of a moderate-energy mound-top environment in the photic zone, sheltered by the mound-front stromatoporoid-coral communities. A mound flank facies is present on the southern side of the mound and this consists of high-energy crinoidal grainstones. Mud-mound deposition was terminated by a transgression that deposited dark gray, fossil-poor marl of the overlying Taravale Formation. The Rocky Camp mound appears to have originated in shallow water photic zone conditions and grew into a high-energy environment, with the mound being eventually colonized by corals and stromatoporoids. The indications of a high-energy environment during later mound growth (growth form of colonial metazoans and grainstones of the flanking facies) suggest that the micrite in the mound was autochthonous and implies the presence of an energy

  9. Volcanic Plume Measurements with UAV (Invited)

    Science.gov (United States)

    Shinohara, H.; Kaneko, T.; Ohminato, T.

    2013-12-01

    Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

  10. System of Volcanic activity

    Directory of Open Access Journals (Sweden)

    P. HÉDERVARI

    1972-06-01

    Full Text Available A comparison is made among the systems of B. G.
    Escher (3, of R. W. van Bemmelen (1 and that of the author (4. In this
    connection, on the basis of Esclier's classification, the terms of "constructiv
    e " and "destructive" eruptions are introduced into the author's system and
    at the same time Escher's concept on the possible relation between the depth
    of magma-chamber and the measure of the gas-pressure is discussed briefly.
    Three complementary remarks to the first paper (4 011 the subject of system
    of volcanic activity are added.

  11. Innovative rubble mound breakwaters for overtopping wave energy conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, Pasquale; Nørgaard, Jørgen Quvang Harck

    2014-01-01

    This paper intends contributing to the development of an economically and environmentally sustainable coastal infrastructure, which combines rubble mound breakwaters with Wave Energy Converters (WEC). The energy is produced by collecting wave overtopping in a front reservoir, which is returned to...

  12. Numerical evaluation of stability methods for rubble mound breakwater toes

    NARCIS (Netherlands)

    Verpoorten, S.P.K.; Ockeloen, W.J.; Verhagen, H.J.

    2015-01-01

    Since 1977 dedicated studies are made to the stability of rubble mound break-water toes under wave attack. A large number of stability methods is available, but prediction accuracy is low and validity ranges are too small for use in prac-tice. In this research the decoupled model approach is used to

  13. Post Earthquack Slope Stability Analysis of Rubble Mound Breakwater

    Directory of Open Access Journals (Sweden)

    Amin Moradi

    2017-03-01

    Full Text Available Rubble mound breakwaters are structures built mainly of quarried rock. Generally armourstone or artificial concrete armour units are used for the outer armour layer,which should protect the structure againist wave attack. Armour stones and concrete armoure unites in this outer layer are usually placed with care to obtain effective interlocking and consequently better stability .

  14. Transient solutions to groundwater mounding in bounded and unbounded aquifers.

    Science.gov (United States)

    Korkmaz, Serdar

    2013-01-01

    In this study, the well-known Hantush solution procedure for groundwater mounding under infinitely long infiltration strips is extended to finite and semi-infinite aquifer cases. Initially, the solution for infinite aquifers is presented and compared to those available in literature and to the numerical results of MODFLOW. For the finite aquifer case, the method of images, which is commonly used in well hydraulics, is used to be able to represent the constant-head boundaries at both sides. It is shown that a finite number of images is enough to obtain the results and sustain the steady state. The effect of parameters on the growth of the mound and on the time required to reach the steady state is investigated. The semi-infinite aquifer case is emphasized because the growth of the mound is not symmetric. As the constant-head boundary limits the growth, the unbounded side grows continuously. For this reason, the groundwater divide shifts toward the unbounded side. An iterative solution procedure is proposed. To perform the necessary computations a code was written in Visual Basic of which the algorithm is presented. The proposed methodology has a wide range of applicability and this is demonstrated using two practical examples. The first one is mounding under a stormwater dispersion trench in an infinite aquifer and the other is infiltration from a flood control channel into a semi-infinite aquifer. Results fit very well with those of MODFLOW.

  15. Oblique wave transmission through rough impermeable rubble mound submerged breawaters

    NARCIS (Netherlands)

    VanLishout, V.; Verhagen, H.J.; Troch, P.

    2011-01-01

    There is a growing interest in the application of submerged rubble mound breakwaters as coastal defence structures. As their defensive ability highly depends on the amount of wave energy remaining at their lee side, the accurate prediction of the energy in the lee of such structures is of utmost imp

  16. Oblique wave transmission through rough impermeable rubble mound submerged breakwaters

    NARCIS (Netherlands)

    Vanlishout, V.; Verhagen, H.J.; Troch, P.

    2010-01-01

    There is a growing interest in the application of submerged rubble mound breakwaters as coastal defence structures. As their defensive ability highly depends on the amount of wave energy remaining at their lee side, the accurate prediction of the energy in the lee of such structures is of utmost imp

  17. Simulating the rubble mound underlying armour units protecting a breakwater

    CSIR Research Space (South Africa)

    Cooper, Antony K

    2010-01-01

    Full Text Available mounds underlying the armour units. In its most primitive form, we model the rubble as a static structure with flat surfaces and then pack the selected armour units on top. This reduces the complexity, but the porosity of the packing close to the rubble...

  18. Avalanche Statistics of Driven Granular Slides in a Miniature Mound

    CERN Document Server

    Juanico, D E; Batac, R; Monterola, C

    2008-01-01

    We examine avalanche statistics of rain- and vibration-driven granular slides in miniature soil mounds using experimental and numerical approaches. A crossover from power-law to non power-law avalanche-size statistics is demonstrated as a generic driving rate $\

  19. Volcanic Catastrophes

    Science.gov (United States)

    Eichelberger, J. C.

    2003-12-01

    The big news from 20th century geophysics may not be plate tectonics but rather the surprise return of catastrophism, following its apparent 19th century defeat to uniformitarianism. Divine miracles and plagues had yielded to the logic of integrating observations of everyday change over time. Yet the brilliant interpretation of the Cretaceous-Tertiary Boundary iridium anomaly introduced an empirically based catastrophism. Undoubtedly, decades of contemplating our own nuclear self-destruction played a role in this. Concepts of nuclear winter, volcanic winter, and meteor impact winter are closely allied. And once the veil of threat of all-out nuclear exchange began to lift, we could begin to imagine slower routes to destruction as "global change". As a way to end our world, fire is a good one. Three-dimensional magma chambers do not have as severe a magnitude limitation as essentially two-dimensional faults. Thus, while we have experienced earthquakes that are as big as they get, we have not experienced volcanic eruptions nearly as great as those preserved in the geologic record. The range extends to events almost three orders of magnitude greater than any eruptions of the 20th century. Such a calamity now would at the very least bring society to a temporary halt globally, and cause death and destruction on a continental scale. At maximum, there is the possibility of hindering photosynthesis and threatening life more generally. It has even been speculated that the relative genetic homogeneity of humankind derives from an evolutionary "bottleneck" from near-extinction in a volcanic cataclysm. This is somewhat more palatable to contemplate than a return to a form of Original Sin, in which we arrived at homogeneity by a sort of "ethnic cleansing". Lacking a written record of truly great eruptions, our sense of human impact must necessarily be aided by archeological and anthropological investigations. For example, there is much to be learned about the influence of

  20. The West Melilla cold water coral mounds, Eastern Alboran Sea: Morphological characterization and environmental context

    Science.gov (United States)

    Lo Iacono, Claudio; Gràcia, Eulàlia; Ranero, Cesar R.; Emelianov, Mikhail; Huvenne, Veerle A. I.; Bartolomé, Rafael; Booth-Rea, Guillermo; Prades, Javier; Ambroso, Stefano; Dominguez, Carlos; Grinyó, Jordi; Rubio, Eduardo; Torrent, Josep

    2014-01-01

    A new mound field, the West Melilla mounds, interpreted as being cold-water coral mounds, has been recently unveiled along the upper slope of the Mediterranean Moroccan continental margin, a few kilometers west of the Cape Tres Forcas. This study is based on the integration of high-resolution geophysical data (swath bathymetry, parametric sub-bottom profiler), CTD casts, Acoustic Doppler Current Profiler (ADCP), ROV video and seafloor sampling, acquired during the TOPOMED GASSIS (2011) and MELCOR (2012) cruises. Up to 103 mounds organized in two main clusters have been recognized in a depth range of 299-590 m, displaying a high density of 5 mounds/km2. Mounds, 1-48 m high above the surrounding seafloor and on average 260 m wide, are actually buried by a 1-12 m thick fine-grained sediment blanket. Seismic data suggest that the West Melilla mounds grew throughout the Early Pleistocene-Holocene, settling on erosive unconformities and mass movement deposits. During the last glacial-interglacial transition, the West Melilla mounds may have suffered a drastic change of the local sedimentary regime during the late Holocene and, unable to stand increasing depositional rates, were progressively buried. At the present day, temperature and salinity values on the West Melilla mounds suggest a plausible oceanographic setting, suitable for live CWCs. Nonetheless, more data is required to groundtruth the West Melilla mounds and better constrain the interplay of sedimentary and oceanographic factors during the evolution of the West Melilla mounds.

  1. IODP Expedition 307 Drills Cold-Water Coral Mound Along the Irish Continental Margin

    Directory of Open Access Journals (Sweden)

    Trevor Williams

    2006-03-01

    Full Text Available Introduction Over the past decade, oceanographic and geophysical surveys along the slope of the Porcupine Seabight off the southwestern continental margin of Ireland have identified upwards of a thousand enigmatic mound-like structures (Figs. 1 and 2. The mounds of the Porcupine Seabight rise from the seafl oor in water depths of 600–900 m and formimpressive conical bodies several kilometers wide and up to 200 m high. Although a few mounds such as Thérèse Mound and Galway Mound are covered by a thriving thicket of coldwater corals, most mound tops and fl anks are covered by dead coral rubble or are entirely buried by sediment (De Mol et al., 2002; Fig. 2, Beyer et al., 2003. Lophelia pertusa (Fig.3 and Madrepora oculata are the most prominent cold-water corals growing without photosynthetic symbionts. The widespread discovery of large and numerous coral-bearing banks and the association of these corals with the mounds have generated signifi cant interest as to the composition, origin and development of these mound structures.Challenger Mound, in the Belgica mound province, has an elongated shape oriented along a north-northeast to south-southwest axis and ispartially buried under Pleistocene drift sediments. In high-resolution seismic profiles the mounds appear to root on an erosion surface (van Rooij et al., 2003. During IODP Expedition307 the Challenger Mound in the Porcupine Seabight was drilled with the goal of unveiling the origin and depositional processes withinthese intriguing sedimentary structures. Challenger Mound, unlike its near neighbors the Thérèse and Galway mounds, has little to no livecoral coverage and, therefore, was chosen as the main target for drilling activities, so that no living ecosystem would be disturbed.

  2. 松南气田营城组火山岩储层建模技术%Geologic modeling of volcanic reservoirs in the Yingcheng Formation of Songnan gas field

    Institute of Scientific and Technical Information of China (English)

    宗畅; 刘华; 王建波

    2012-01-01

    火山岩具有结构复杂、岩性岩相变化快、储层非均质性强等特点,从而使火山岩储层的地质建模工作变得十分复杂。在借鉴松辽盆地徐深气田火山岩储层建模技术和经验的基础上,以松辽盆地松南气田为例,运用建模软件开展了该区的储层建模工作。利用钻井、测井、地震、岩心分析等资料完成了火山岩期次的划分,建立起了松南气田地层格架,并在此基础上,结合综合地质研究成果,建立了该区的构造模型及属性模型。其研究成果与后续开发井钻探结果符合性较好,为气藏开发决策提供了依据。%Volcanic rocks are characterized by complex structure,rapid change of lithology and facies,and strong heterogeneity of reservoirs,thus geologic modeling is very hard.Based on the experiences of the geologic modeling of the volcanic reservoirs in the Xushen gas field,we carried out the geologic modeling of the volcanic reservoirs in the Songnan gas field,Songliao Basin.Various data including drilling,logging,seismic data and core analysis were integrated to perform volcanic period's division and correlation and to establish the stratigraphic framework of the Songnan gas field.These study results,in combination with those of the comprehensive geologic research,were utilized to build structural models and attribute models of the study area.The prediction results have been validated by the follow-up development drilling results.These understandings provided a strong foundation for strategic decision making of gas field development.

  3. Geochemical study for volcanic surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Panichi, C.; La Ruffa, G. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research Ghezzano, PI (Italy)

    2000-07-01

    For years, geologists have been striving to reconstruct volcanic eruptions from the analysis of pyroclastic deposits and lava flows on the surface of the earth and in the oceans. This effort has produced valuable information on volcanic petrology and magma generation, separation, mixing, crystallisation, and interaction with water in phreatomagmatic and submarine eruptions. The volcanological process are tied to the dynamics of the earth's crust and lithosphere. The mantle, subducted oceanic crust, and continental crust contain different rock types and are sources of different magmas. Magmas consist primarily of completely or partially molten silicates containing volatile materials either dissolved in the melt or as bubbles of gas. The silicate and volatile portions affect the physical properties of magma and, therefore, the nature of a volcanic eruption.

  4. A mounded spherical storage tank at Papeete; Une sphere sous talus a Papeete

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-09-01

    Because demand for liquid petroleum gas (LPG) in French Polynesia is burgeoning, deliveries of the product are on the rise, in particular from New Zealand. In consideration of this, Gaz de Tahiti has had a mounded 1.800 m{sup 3} spherical propane storage tank built by the Tissot group. The new tank joins the ranks of the standard 2.500 m{sup 3} spherical butane tank that Gaz de Tahiti already has at its Papeete site. The slope consists of earth-filled gabions, which are at least one metre thick at any point of the steel structure. The project is proof once again that Gaz de Tahiti has no reason to envy European companies when it comes to technology and development. (authors)

  5. Displacement of Monolithic Rubble-Mound Breakwater Crown-Walls

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke

    2012-01-01

    studies on caisson breakwaters, but correction terms are suggested in the present paper to obtain almost equal measured and estimated displacements. This is of great practical importance since many existing rubble-mound crown-walls are subjected to increasing wave loads due to rising sea water level from......This paper evaluates the validity of a simple one-dimensional dynamic analysis as well as a Finite-Element model to determine the sliding of a rubble-mound breakwater crown-wall. The evaluation is based on a case example with real wave load time-series and displacements measured from two...... of the accumulated sliding distance of crown-wall superstructures, which is in contrast to findings from previous similar studies on caisson breakwaters. The calculated sliding distance is approximately three times larger than the measured one when using the original one-dimensional model suggested in previous...

  6. Design And Construction Of Mounds For Breakwaters And Coastal Protection

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Barends, F.B.J.; Brebner, A.

    Design and construction of mound breakwaters has during the last 5 to 10 years entered a new era. The major reason for that is the realization of problems encountered as it became necessary to erect port structures on more exposed shores and in deeper waters. As a consequence of that the P.......I.A.N.C . (Permanent International Association of Navigation Congresses) established several "Waves Committees" to deal with wave criteria useful for design as well as with the interact.ion between waves and structure s (21). Other institutes or agencies held special wave seminars or breakwater symposia. Progress...... they were exposed to. The following sections discuss the stability of mound breakwaters, reasons for failure and design principles. A number of major failures are mentioned specifically. In each case an attempt has been made to explore and explain the reason for the failure....

  7. Temporal variability in shell mound formation at Albatross Bay, northern Australia.

    Science.gov (United States)

    Holdaway, Simon J; Fanning, Patricia C; Petchey, Fiona; Allely, Kasey; Shiner, Justin I; Bailey, Geoffrey

    2017-01-01

    We report the results of 212 radiocarbon determinations from the archaeological excavation of 70 shell mound deposits in the Wathayn region of Albatross Bay, Australia. This is an intensive study of a closely co-located group of mounds within a geographically restricted area in a wider region where many more shell mounds have been reported. Valves from the bivalve Tegillarca granosa (Linnaeus, 1758) were dated. The dates obtained are used to calculate rates of accumulation for the shell mound deposits. These demonstrate highly variable rates of accumulation both within and between mounds. We assess these results in relation to likely mechanisms of shell deposition and show that rates of deposition are affected by time-dependent processes both during the accumulation of shell deposits and during their subsequent deformation. This complicates the interpretation of the rates at which shell mound deposits appear to have accumulated. At Wathayn, there is little temporal or spatial consistency in the rates at which mounds accumulated. Comparisons between the Wathayn results and those obtained from shell deposits elsewhere, both in the wider Albatross Bay region and worldwide, suggest the need for caution when deriving behavioural inferences from shell mound deposition rates, and the need for more comprehensive sampling of individual mounds and groups of mounds.

  8. Submarine Volcanic Morphology of Santorini Caldera, Greece

    Science.gov (United States)

    Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.

    2012-04-01

    Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at

  9. 火山岩气藏储层岩相特征及其对储层物性的影响——以徐深气田徐东地区白垩系营城组一段火山岩为例%Lithofacies characteristics of volcanic gas reservoirs and their influence on reservoir physical properties: a case study of Member 1 of Cretaceous Yingcheng Formation in Xudong area of the Xushen gas field

    Institute of Scientific and Technical Information of China (English)

    陈欢庆; 胡永乐; 冉启全; 闫林; 孙作兴

    2011-01-01

    Taking the volcanic reservoir of Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field as an example, the authors studied lithofacies characteristics of the volcanic gas reservoir and their influences on reservoir physical properties with the purpose of effectively forecasting and exploiting the volcanic reservoir.On the basis of identification of volcanic rock types and recognition of volcanic rock bodies by combining geological data with logging data and seismic data, the authors analyzed volcanic lithofacies characteristics and their relationship with reservoir physical properties and forecast the favorable prospecting areas by using data from wells, sections and plane lithofacies.The results indicate that the volcanic reservoir of the Member 1 of Yingcheng Formation in Xudong area of the Xushen gas field was formed by repeated volcanic eruptions, with the lithologies consisting of 10 types.The rhyolite, rhyolite tuff and sedimentary volcanic breccia played the preponderant role.The eruption type in the study area was cranny-center eruption, and crater and volcanic lithofacies were obviously controlled by ruptures.The volcanic bodies were dominated by craters, and different volcanic lithofacies were developed in different positions of volcanic bodies.The volcanic fades inside the volcanic bodies in the study area can be divided into five types and sixteen sub-facies.The results indicate that the volcanic lithology and its combination constitute the basis of the division of volcanic fades, and the spreading of volcanic fades controls the distribution of gas reservoirs.The reservoir development areas include the lower part and upper part and top overflow sub-facies of overflow facies, splash down sub-facies and air falling sub-facies, middle extrusive sub-facies, exterior sub-facies of extrusive facies and volcanic neck sub-facies of volcanic channels facies.The sub-facies of the volcanic reservoir include volcanic sub-lithfacies of volcanic neck

  10. Anomalous increase of diffuse CO_{2} emission from Brava (Cape Verde): evidence of volcanic unrest or increase gas release from a stationary magma body?

    Science.gov (United States)

    García-Merino, Marta; García-Hernández, Rubén; Montrond, Eurico; Dionis, Samara; Fernandes, Paulo; Silva, Sonia V.; Alfama, Vera; Cabral, Jeremías; Pereira, Jose M.; Padrón, Eleazar; Pérez, Nemesio M.

    2017-04-01

    Brava (67 km2) is the southwestern most and the smallest inhabited island of the Cape Verde archipelago. It is located 18 km west of Fogo Island and rises 976 m from the sea level. Brava has not any documented historical eruptions, but its Holocene volcanism and relatively high seismic activity clearly indicate that it is an active volcanic island. Since there have been no historic eruptions in Brava, volcanic hazard awareness among the population and the authorities is very low; therefore, its volcano monitoring program is scarce. With the aim of helping to provide a multidisciplinary monitoring program for the volcanic surveillance of the island, diffuse CO2 emission surveys have been carried out since 2010; approximately every 2 years. Soil CO2 efflux measurements are periodically performed at ˜ 275 observation sites all over the island and after taking into consideration their accessibility and the island volcano-structural characteristics. At each sampling site, soil CO2 efflux measurement was performed by means of a portable NDIR sensor according to the accumulation chamber method. To quantify the total diffuse CO2 emission from Brava volcanic system, soil CO2 efflux maps were constructed using sequential Gaussian simulations (sGs). An increase trend of diffuse CO2 emission rate from 42 to 681 t d-1at Brava was observed; just one year prior the 2014-2015 Fogo eruption and almost three years before the anomalous seismic activity recorded on August 2016 with more than 1000 seismic events registered by the INMG on August 1st, 2016 (Bruno Faria, personal communication). Due to this anomalous seismic activity, a diffuse CO2 emission survey at Brava was performed from August 2 to 10, 2016, and the estimated degassing rate yield a value about 72 t d-1; typical background values. An additional survey was carried out from October 22 to November 6, 2016. For this last survey, the estimated diffuse CO2 emission from Brava showed the highest observed value with a

  11. Volcanic hazard management in dispersed volcanism areas

    Science.gov (United States)

    Marrero, Jose Manuel; Garcia, Alicia; Ortiz, Ramon

    2014-05-01

    Traditional volcanic hazard methodologies were developed mainly to deal with the big stratovolcanoes. In such type of volcanoes, the hazard map is an important tool for decision-makers not only during a volcanic crisis but also for territorial planning. According to the past and recent eruptions of a volcano, all possible volcanic hazards are modelled and included in the hazard map. Combining the hazard map with the Event Tree the impact area can be zoned and defining the likely eruptive scenarios that will be used during a real volcanic crisis. But in areas of disperse volcanism is very complex to apply the same volcanic hazard methodologies. The event tree do not take into account unknown vents, because the spatial concepts included in it are only related with the distance reached by volcanic hazards. The volcanic hazard simulation is also difficult because the vent scatter modifies the results. The volcanic susceptibility try to solve this problem, calculating the most likely areas to have an eruption, but the differences between low and large values obtained are often very small. In these conditions the traditional hazard map effectiveness could be questioned, making necessary a change in the concept of hazard map. Instead to delimit the potential impact areas, the hazard map should show the expected behaviour of the volcanic activity and how the differences in the landscape and internal geo-structures could condition such behaviour. This approach has been carried out in La Palma (Canary Islands), combining the concept of long-term hazard map with the short-term volcanic scenario to show the expected volcanic activity behaviour. The objective is the decision-makers understand how a volcanic crisis could be and what kind of mitigation measurement and strategy could be used.

  12. Alternation of microbial mounds and ooid shoals (Middle Jurasssic, Morocco): Response to paleoenvironmental changes

    Science.gov (United States)

    Tomás, Sara; Homann, Martin; Mutti, Maria; Amour, Frédéric; Christ, Nicolas; Immenhauser, Adrian; Agar, Susan M.; Kabiri, Lahcen

    2013-08-01

    The occurrence of neritic microbial carbonates is often related to ecological refuges, where grazers and other competitors are reduced by environmental conditions, or to post-extinction events (e.g. in the Late Devonian, Early Triassic). Here, we present evidence for Middle Jurassic (Bajocian) microbial mounds formed in the normal marine, shallow neritic setting of an inner, ramp system from the High Atlas of Morocco. The microbial mounds are embedded in cross-bedded oolitic facies. Individual mounds show low relief domal geometries (up to 3 m high and 4.5 m across), but occasionally a second generation of mounds exhibits tabular geometries (motivation for the present study. Specifically, Bajocian mounds formed on a firmground substratum during transgressive phases under condensed sedimentation. Furthermore, a transient increase in nutrient supply in the prevailing mesotrophic setting, as suggested by the heterotrophic-dominated biota, may have controlled microbial mound stages.

  13. Sediment dynamics and palaeo-environmental context at key stages in the Challenger cold-water coral mound formation: Clues from sediment deposits at the mound base

    Science.gov (United States)

    Huvenne, Veerle Ann Ida; Van Rooij, David; De Mol, Ben; Thierens, Mieke; O'Donnell, Rory; Foubert, Anneleen

    2009-12-01

    IODP Expedition 307, targeting the 160 m high Challenger Mound and its surroundings in the Porcupine Seabight, NE Atlantic, was the first occasion of scientific drilling of a cold-water coral carbonate mound. Such mound structures are found at several locations along the continental margin but are especially numerous off Ireland. All rooted on a common unconformity (RD1) and embedded in drift sediments, the mounds in the Porcupine Seabight remain enigmatic structures, and their initial trigger and formation mechanisms are still not entirely clear. This paper discusses the sedimentary environment during the initial stages of Challenger Mound, and at the start-up of the embedding sediment drift. The results are interpreted within the regional palaeo-environmental context. Based on detailed grain-size analyses and planktonic foraminifera assemblage counts, a 14-m interval overlying the regional base-of-mound unconformity RD1 is characterised at IODP Sites U1317 (on mound), U1316 (off mound), and U1318 (background site). Several sedimentary facies are identified and interpreted in relation to regional current dynamics. Using the foraminifera counts, existing age models for the initial stages of on-mound and off-mound sedimentation are refined. Sedimentation within the initial mound was characterised by a two-mode system, with the observed cyclicities related to glacial/interglacial stages. However, the contrast in environmental conditions between the stages was less extreme than observed in the most recent glacial/interglacial cycles, allowing continuous cold-water coral growth. This sustained presence of coral framework was the key factor for fast mound build-up, baffling sediments at periods of slack currents, and protecting them from renewed erosion during high-current events. The off-mound and background sedimentation consisted mainly of a succession of contourite beds, ranging from sandy contourites in the initial stages to muddy contourites higher up in the

  14. Uranium series, volcanic rocks

    Science.gov (United States)

    Vazquez, Jorge A.

    2014-01-01

    Application of U-series dating to volcanic rocks provides unique and valuable information about the absolute timing of crystallization and differentiation of magmas prior to eruption. The 238U–230Th and 230Th-226Ra methods are the most commonly employed for dating the crystallization of mafic to silicic magmas that erupt at volcanoes. Dates derived from the U–Th and Ra–Th methods reflect crystallization because diffusion of these elements at magmatic temperatures is sluggish (Cherniak 2010) and diffusive re-equilibration is insignificant over the timescales (less than or equal to 10^5 years) typically associated with pre-eruptive storage of nearly all magma compositions (Cooper and Reid 2008). Other dating methods based on elements that diffuse rapidly at magmatic temperatures, such as the 40Ar/39Ar and (U–Th)/He methods, yield dates for the cooling of magma at the time of eruption. Disequilibrium of some short-lived daughters of the uranium series such as 210Po may be fractionated by saturation of a volatile phase and can be employed to date magmatic gas loss that is synchronous with volcanic eruption (e.g., Rubin et al. 1994).

  15. Volcanic Eruptions and Climate

    Science.gov (United States)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  16. Bug Hill: Excavation of a Multicomponent Midden Mound in the Jackfork Valley, Pushmataha County, Southeast Oklahoma.

    Science.gov (United States)

    1983-11-25

    settlements. 15 i. MIDDEN MOUND ARCHAEOLOGY AND BUG HILL Throughout this section, there has been one recurrent theme: the inability to "see" within a...processes can be involved. For instance, sites experiencing recurrent seasonal flooding often have alluvial soils forming a main component of the mound...0 1944 Dental abnormalities as found in the American Indian. American Journal of Orthodontics and Oral Surgery 30(9):474-486. 1959 The Belcher Mound

  17. Nutrient dynamics and plant assemblages of Macrotermes falciger mounds in a savanna ecosystem

    Science.gov (United States)

    Muvengwi, Justice; Ndagurwa, Hilton G. T.; Nyenda, Tatenda; Mbiba, Monicah

    2016-10-01

    Termites through mound construction and foraging activities contribute significantly to carbon and nutrient fluxes in nutrient-poor savannas. Despite this recognition, studies on the influence of termite mounds on carbon and nitrogen dynamics in sub-tropical savannas are limited. In this regard, we examined soil nutrient concentrations, organic carbon and nitrogen mineralization in incubation experiments in mounds of Macrotermes falciger and surrounding soils of sub-tropical savanna, northeast Zimbabwe. We also addressed whether termite mounds altered the plant community and if effects were similar across functional groups i.e. grasses, forbs or woody plants. Mound soils had significantly higher silt and clay content, pH and concentrations of calcium (Ca), magnesium (Mg), potassium (K), organic carbon (C), ammonium (NH4+) and nitrate (NO3-) than surrounding soils, with marginal differences in phosphorus (P) and sodium (Na) between mounds and matrix soils. Nutrient enrichment increased by a factor ranging from 1.5 for C, 4.9 for Mg up to 10.3 for Ca. Although C mineralization, nitrification and nitrification fraction were similar between mounds and matrix soils, nitrogen mineralization was elevated on mounds relative to surrounding matrix soils. As a result, termite mounds supported unique plant communities rich and abundant in woody species but less diverse in grasses and forbs than the surrounding savanna matrix in response to mound-induced shifts in soil parameters specifically increased clay content, drainage and water availability, nutrient status and base cation (mainly Ca, Mg and Na) concentration. In conclusion, by altering soil properties such as texture, moisture content and nutrient status, termite mounds can alter the structure and composition of sub-tropical savanna plant communities, and these results are consistent with findings in other savanna systems suggesting that increase in soil clay content, nutrient status and associated changes in the plant

  18. Imported fire ant (Hymenoptera: Formicidae) mound shape characteristics along a north-south gradient.

    Science.gov (United States)

    Vogt, James T; Wallet, Bradley; Freeland, Thomas B

    2008-02-01

    The nests of some mound-building ants are thought to serve an important function as passive solar collectors. To test this hypothesis, imported fire ant (Solenopsis invicta Buren, S. richteri Forel, and their hybrid) mound shape characteristics (south facing slope angle and area, mound height, and basal elongation in the plane of the ground) were quantified in 2005 and 2006 at a number of locations from approximately 30 degrees 25' N (Long Beach, MS) to 35 degrees 3' N (Fayetteville, TN). Insolation (w*h/m2), maximum sun angle (sun elevation in degrees above the horizon at noon, dependent on date and latitude), cumulative rainfall (7 and 30 d before sampling), and mean ambient temperature (7 d before sampling) for each site x date combination were used as predictive variables to explain mound shape characteristics. Steepness of south-facing mound slopes was negatively associated with maximum sun angle at higher temperatures, with predicted values falling from approximately 36 degrees at sun angle=40 degrees to 26 degrees at sun angle=70 degrees; at lower temperatures, slope remained relatively constant at 28 degrees. On average, mound height was negatively correlated with maximum sun angle. Rainfall had a net negative effect on mound height, but mound height increased slightly with maximum sun angle when rainfall was high. Mound elongation generally increased with increased mound building activity. Under favorable temperature conditions and average rainfall, imported fire ant mounds were tallest, most eccentric, and had the steepest south facing slopes during periods of low maximum sun angle. Mound shape characteristics are discussed with regard to season and their potential usefulness for remote sensing efforts.

  19. Experimental generation of volcanic lightning

    Science.gov (United States)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Kueppers, Ulrich; Scheu, Bettina; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes that are responsible for injecting large quantities of aerosols into the atmosphere are often associated with intense electrical activity. Direct measurement of the electric potential at the crater, where the electric activity in the volcanic plume is first observed, is severely impeded, limiting progress in its investigation. We have achieved volcanic lightning in the laboratory during rapid decompression experiments of gas-particle mixtures under controlled conditions. Upon decompression (from ~100 bar argon pressure to atmospheric pressure), loose particles are vertically accelerated and ejected through a nozzle of 2.8 cm diameter into a large tank filled with air at atmospheric conditions. Because of their impulsive character, our experiments most closely represent the conditions encountered in the gas-thrust region of the plume, when ash is first ejected from the crater. We used sieved natural ash with different grain sizes from Popocatépetl (Mexico), Eyjafjallajökull (Iceland), and Soufrière Hills (Montserrat) volcanoes, as well as micrometric glass beads to constrain the influence of material properties on lightning. We monitored the dynamics of the particle-laden jets with a high-speed camera and the pressure and electric potential at the nozzle using a pressure transducer and two copper ring antennas connected to a high-impedance data acquisition system, respectively. We find that lightning is controlled by the dynamics of the particle-laden jet and by the abundance of fine particles. Two main conditions are required to generate lightning: 1) self-electrification of the particles and 2) clustering of the particles driven by the jet fluid dynamics. The relative movement of clusters of charged particles within the plume generates the gradient in electrical potential, which is necessary for lightning. In this manner it is the gas-particle dynamics together with the evolving particle-density distribution within different regions of

  20. Volcanic hazard assessment in monogenetic volcanic fields

    OpenAIRE

    Bartolini, Stefania

    2014-01-01

    [eng] One of the most important tasks of modern volcanology, which represents a significant socio-economic implication, is to conduct hazard assessment in active volcanic systems. These volcanological studies are aimed at hazard that allows to constructing hazard maps and simulating different eruptive scenarios, and are mainly addressed to contribute to territorial planning, definition of emergency plans or managing volcanic crisis. The impact of a natural event, as a volcanic eruption, can s...

  1. SPATIAL VARIABILITY AND VITALITY OF EPIGEOUS TERMITE MOUNDS IN PASTURES OF MATO GROSSO DO SUL, BRAZIL

    Directory of Open Access Journals (Sweden)

    Sandra Santana Lima

    2015-02-01

    Full Text Available Epigeous termite mounds are frequently observed in pasture areas, but the processes regulating their population dynamics are poorly known. This study evaluated epigeous termite mounds in cultivated grasslands used as pastures, assessing their spatial distribution by means of geostatistics and evaluating their vitality. The study was conducted in the Cerrado biome in the municipality of Rio Brilhante, Mato Grosso do Sul, Brazil. In two pasture areas (Pasture 1 and Pasture 2, epigeous mounds (nests were georeferenced and analyzed for height, circumference and vitality (inhabited or not. The area occupied by the mounds was calculated and termite specimens were collected for taxonomic identification. The spatial distribution pattern of the mounds was analyzed with geostatistical procedures. In both pasture areas, all epigeous mounds were built by the same species, Cornitermes cumulans. The mean number of mounds per hectare was 68 in Pasture 1 and 127 in Pasture 2, representing 0.4 and 1 % of the entire area, respectively. A large majority of the mounds were active (vitality, 91 % in Pasture 1 and 84 % in Pasture 2. A “pure nugget effect” was observed in the semivariograms of height and nest circumference in both pastures reflecting randomized spatial distribution and confirming that the distribution of termite mounds in pastures had a non-standard distribution.

  2. Long-lived volcanism within Argyre basin, Mars

    Science.gov (United States)

    Williams, Jean-Pierre; Dohm, James M.; Soare, Richard J.; Flahaut, Jessica; Lopes, Rosaly M. C.; Pathare, Asmin V.; Fairén, Alberto G.; Schulze-Makuch, Dirk; Buczkowski, Debra L.

    2017-09-01

    The Argyre basin, one of the largest impact structures on Mars with a diameter >1200 km, formed in the Early Noachian ∼3.93 Ga. The basin has collected volatiles and other material through time, and experienced partial infilling with water evident from stratigraphic sequences, crater statistics, topography, and geomorphology. Although volcanism has not been previously associated with the Argyre basin, our study of the northwest portion of the basin floor has revealed landforms suggesting volcanic and tectonic activity occurred including Argyre Mons, a ∼50 km wide volcanic-structure formed ∼3 Ga. Giant polygons with a similar surface age are also identified on terrain adjacent to the base of Argyre Mons, indicating the structure may have formed in a water-rich environment. In addition to Argyre Mons, cones, vents, mounds, dikes, and cavi or hollows, many of which are associated with extensional tectonics, are observed in the region. Multiple features appear to disrupt icy (and largely uncratered) terrain indicating a relatively young, Late Amazonian, formation age for at least some of the volcanic and tectonic features. The discovery of Argyre Mons, along with additional endogenic modification of the basin floor, suggests that the region has experienced episodes of volcanism over a protracted period of time. This has implications for habitability as the basin floor has been a region of elevated heat flow coupled with liquid water, water ice, and accumulation of sediments of diverse provenance with ranging geochemistry, along with magma-water interactions.

  3. Organic matter remains in the Kess Kess mounds of the Hamar Laghadad (Anti Atlas, Morocco): record of microbial biomineralization

    Science.gov (United States)

    Demasi, Fabio; Barbieri, Roberto; Guido, Adriano; Mastandrea, Adelaide; Cavalazzi, Barbara; Russo, Franco

    2010-05-01

    between 1300 and 1100 cm-1. We recorded also the band νC=C probably related to unsatured compounds (alkene and/or carboxylic acids). The organic matter correlated to the fine laminated micrite is characterized by the presence of stretching C=C vibrations. The lack of bands in the 700-900 cm-1 and 3000-3100 cm-1regions permits to exclude that νC=C band belongs to aromatic compounds. We attribute this band to alkene and/or unsatured carboxylic acids that could have been synthesized by bacteria and/or archaea communities, which caused the precipitation of carbonates through their metabolic activities. We used the A Factor (2930+2860 cm-1)/(2930+2860+1630 cm-1) and a C Factor (1710 cm-1)/(1710 + 1630 cm-1) in order to quantify changes in abundances of aliphatic and carbonyl/carboxyl groups. These factors can be used in a similar manner to the traditional H/C - O/C elemental ratios or to Rock-Eval pyrolysis parameters, as Hydrogen Index (HI) - Oxygen Index (OI), for the classification of kerogen types and maturation level of organic compounds. In the analyzed samples, the A factor is ~0.70 while the C factor is ~0.63. These parameters indicate a marine origin for the organic compounds and a low thermal evolution. Considering the thermal maturity of the organic compounds, further analyses in Gas Cromatography-Mass Spectrometry could confirm the presence of specific bacterial/archaeal biomarkers. These analyses will clarify the microbial metabolic activities that induced biomineralization processes in the Kess Kess Mound.

  4. Plant Mounds as Concentration and Stabilization Agents for Actinide Soil Contaminants in Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D.S. Shafer; J. Gommes

    2009-02-03

    Plant mounds or blow-sand mounds are accumulations of soil particles and plant debris around the base of shrubs and are common features in deserts in the southwestern United States. An important factor in their formation is that shrubs create surface roughness that causes wind-suspended particles to be deposited and resist further suspension. Shrub mounds occur in some plant communities on the Nevada Test Site, the Nevada Test and Training Range (NTTR), and Tonopah Test Range (TTR), including areas of surface soil contamination from past nuclear testing. In the 1970s as part of early studies to understand properties of actinides in the environment, the Nevada Applied Ecology Group (NAEG) examined the accumulation of isotopes of Pu, 241Am, and U in plant mounds at safety experiment and storage-transportation test sites of nuclear devices. Although aerial concentrations of these contaminants were highest in the intershrub or desert pavement areas, the concentration in mounds were higher than in equal volumes of intershrub or desert pavement soil. The NAEG studies found the ratio of contaminant concentration of actinides in soil to be greater (1.6 to 2.0) in shrub mounds than in the surrounding areas of desert pavement. At Project 57 on the NTTR, 17 percent of the area was covered in mounds while at Clean Slate III on the TTR, 32 percent of the area was covered in mounds. If equivalent volumes of contaminated soil were compared between mounds and desert pavement areas at these sites, then the former might contain as much as 34 and 62 percent of the contaminant inventory, respectively. Not accounting for radionuclides associated with shrub mounds would cause the inventory of contaminants and potential exposure to be underestimated. In addition, preservation of shrub mounds could be important part of long-term stewardship if these sites are closed by fencing and posting with administrative controls.

  5. Morphology and spatial patterns of Macrotermes mounds in the SE Katanga, D.R. Congo

    Science.gov (United States)

    Bazirake Mujinya, Basile; Mees, Florias; Erens, Hans; Baert, Geert; Van Ranst, Eric

    2015-04-01

    The spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds were investigated in the Lubumbashi area, D.R. Congo. Examination of the spatial patterns of M. falciger mounds on high resolution satellite images reveals a mean areal number density of 2.9 ± 0.4 mounds ha-1. The high relative number of inactive mounds in the region, along with their regular distribution pattern, suggests that current termite mound occurrences are largely palaeostructures. Mound positions in the habitat are consistent with intraspecific competition rather than soil and substrate characteristics as controlling factor. Detailed morphological description of five deep termite-mound profiles (~7 m height/depth) shows that carbonate pedofeatures are present in all studied profiles, in contrast to the control soils. They mainly occur in the form of soft powdery masses, nodules and coatings on ped faces, all clearly pedogenic. Carbonate coatings occur mainly between 1 m above the soil surface and 1 m below that level in all mound profiles. Carbonate nodules do show a different distribution pattern at each site. Furthermore, when the studied profiles are considered to represent a toposequence, the stone layer occurs at greater depth in topographically low areas compared to crest and slope positions, which is mainly conditioned by erosion. The clay content of epigeal mounds increases from the summit to the toe slope, which can be largely related to differences in parent material. The Mn-Fe oxide concentrations occurring in all studied termite mound profiles reflect a seasonally high perched water table beneath the mound, which is more pronounced at the lower slope positions.

  6. Famennian mud-mounds in the proximal fore-reef slope, Canning Basin, Western Australia

    Science.gov (United States)

    Webb, Gregory E.

    2001-12-01

    Famennian (Late Devonian) carbonate buildups and, in particular, mud-mounds, are poorly known, in general, and few have been documented in detail. Relatively small Famennian mud-mounds occur in proximal fore-reef slope settings in the Canning Basin, Western Australia. The Famennian platform margin facies passes from typical shoaling carbonate facies in the back reef, through massive, calcimicrobial, cement-rich reef-margin facies, to relatively steeply dipping (20-30°), well-bedded fore-reef slope facies containing shelf-derived, winnowed grainy sediments and extremely coarse reef-block debris. Isolated or coalescing mounds occur in the proximal slope, immediately adjacent to and, in some cases, possibly grading into the margin facies. Mounds are elongate perpendicular to the margin and some had synoptic relief greater than 2 m. Mounds are lithologically variable and consist of varying proportions of micrite, multiple generations of marine cement, abundant Rothpletzella, Renalcis, poorly preserved sparry microbial crusts and sporadically distributed laminar stromatoporoids. Surrounding grainy slope facies abut and slope off of mound flanks. Mound facies are very similar to nearby reef-margin facies, with the exceptions that stromatoporoids have not been observed in margin facies and solenoporoid algae, which occur in the margin, have not been observed in the mounds. Stromatolites are conspicuously absent from both facies. Mound facies appear to be more closely related to Frasnian and Famennian calcimicrobe cement-dominated reef-margin facies than to Famennian deep-water stromatolite-sponge-mound facies, such as those that occur elsewhere in the Canning Basin. The observed Canning Famennian reef and mound frameworks were constructed by communities that appear to be very similar to earlier Frasnian communities, despite the Frasnian-Famennian extinction event, and provide good examples of microbial reef framework construction in a high energy setting.

  7. Characteristics and origin of Earth-mounds on the Eastern Snake River Plain, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.A.

    1995-09-01

    Earth-mounds are common features on the Eastern Snake River Plain, Idaho. The mounds are typically round or oval in plan view, <0.5 m in height, and from 8 to 14 m in diameter. They are found on flat and sloped surfaces, and appear less frequently in lowland areas. The mounds have formed on deposits of multiple sedimentary environments. Those studied included alluvial gravel terraces along the Big Lost River (late Pleistocene/early Holocene age), alluvial fan segments on the flanks of the Lost River Range (Bull Lake and Pinedale age equivalents), and loess/slopewash sediments overlying basalt flows. Backhoe trenches were dug to allow characterization of stratigraphy and soil development. Each mound has features unique to the depositional and pedogenic history of the site; however, there are common elements to all mounds that are linked to the history of mound formation. Each mound has a {open_quotes}floor{close_quotes} of a sediment or basement rock of significantly different hydraulic conductivity than the overlying sediment. These paleosurfaces are overlain by finer-grained sediments, typically loess or flood-overbank deposits. Mounds formed in environments where a sufficient thickness of fine-grained sediment held pore water in a system open to the migration to a freezing front. Heaving of the sediment occurred by the growth of ice lenses. Mound formation occurred at the end of the Late Pleistocene or early in the Holocene, and was followed by pedogenesis. Soils in the mounds were subsequently altered by bioturbation, buried by eolian deposition, and eroded by slopewash runoff. These secondary processes played a significant role in maintaining or increasing the mound/intermound relief.

  8. Sedimentation patterns on a cold-water coral mound off Mauritania

    NARCIS (Netherlands)

    Eisele, M.; Frank, N.; Wienberg, C.; Titschack, J.; Mienis, F; Beuck, L.; Tisnerat-Laborde, N.; Hebbeln, D.

    2014-01-01

    An unconformity-bound glacial sequence (135 cm thick) of a coral-bearing sediment core collected from the flank of a cold-water coral mound in the Banda Mound Province off Mauritania was analysed. In order to study the relation between coral framework growth and its filling by hemipelagic sediments,

  9. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    Science.gov (United States)

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  10. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    Science.gov (United States)

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  11. Formation and Control of Self-Sealing High Permeability Groundwater Mounds in Impermeable Sediment: Implications for SUDS and Sustainable Pressure Mound Management

    Directory of Open Access Journals (Sweden)

    David D. J. Antia

    2009-10-01

    Full Text Available A groundwater mound (or pressure mound is defined as a volume of fluid dominated by viscous flow contained within a sediment volume where the dominant fluid flow is by Knudsen Diffusion. High permeability self-sealing groundwater mounds can be created as part of a sustainable urban drainage scheme (SUDS using infiltration devices. This study considers how they form, and models their expansion and growth as a function of infiltration device recharge. The mounds grow through lateral macropore propagation within a Dupuit envelope. Excess pressure relief is through propagating vertical surge shafts. These surge shafts can, when they intersect the ground surface result, in high volume overland flow. The study considers that the creation of self-sealing groundwater mounds in matrix supported (clayey sediments (intrinsic permeability = 10–8 to 10–30 m3 m–2 s–1 Pa–1 is a low cost, sustainable method which can be used to dispose of large volumes of storm runoff (<20→2,000 m3/24 hr storm/infiltration device and raise groundwater levels. However, the inappropriate location of pressure mounds can result in repeated seepage and ephemeral spring formation associated with substantial volumes of uncontrolled overland flow. The flow rate and flood volume associated with each overland flow event may be substantially larger than the associated recharge to the pressure mound. In some instances, the volume discharged as overland flow in a few hours may exceed the total storm water recharge to the groundwater mound over the previous three weeks. Macropore modeling is used within the context of a pressure mound poro-elastic fluid expulsion model in order to analyze this phenomena and determine (i how this phenomena can be used to extract large volumes of stored filtered storm water (at high flow rates from within a self-sealing high permeability pressure mound and (ii how self-sealing pressure mounds (created using storm water infiltration can be used to

  12. On the influence of cold-water coral mound size on flow hydrodynamics, and vice versa

    Science.gov (United States)

    Cyr, Frédéric; Haren, Hans; Mienis, Furu; Duineveld, Gerard; Bourgault, Daniel

    2016-01-01

    Using a combination of in situ observations and idealistic 2-D nonhydrostatic numerical simulations, the relation between cold-water coral (CWC) mound size and hydrodynamics is explored for the Rockall Bank area in the North Atlantic Ocean. It is shown that currents generated by topographically trapped tidal waves in this area cause large isopycnal depressions resulting from an internal hydraulic control above CWC mounds. The oxygen concentration distribution is used as a tracer to visualize the flow behavior and the turbulent mixing above the mounds. By comparing two CWC mounds of different sizes and located close to each other, it is shown that the resulting mixing is highly dependent on the size of the mound. The effects of the hydraulic control for mixing, nutrient availability, and ecosystem functioning are also discussed.

  13. Distinguishing contributions to diffuse CO2 emissions in volcanic areas from magmatic degassing and thermal decarbonation using soil gas 222Rn-δ13C systematics: Application to Santorini volcano, Greece

    Science.gov (United States)

    Parks, Michelle M.; Caliro, Stefano; Chiodini, Giovanni; Pyle, David M.; Mather, Tamsin A.; Berlo, Kim; Edmonds, Marie; Biggs, Juliet; Nomikou, Paraskevi; Raptakis, Costas

    2013-09-01

    Between January 2011 and April 2012, Santorini volcano (Greece) experienced a period of unrest characterised by the onset of detectable seismicity and caldera-wide uplift. This episode of inflation represented the first sizeable intrusion of magma beneath Santorini in the past 50 years. We employ a new approach using 222Rn-δ13C systematics to identify and quantify the source of diffuse degassing at Santorini during the period of renewed activity. Soil CO2 flux measurements were made across a network of sites on Nea Kameni between September 2010 and January 2012. Gas samples were collected in April and September 2011 for isotopic analysis of CO2 (δ13C), and radon detectors were deployed during September 2011 to measure (222Rn). Our results reveal a change in the pattern of degassing from the summit of the volcano (Nea Kameni) and suggest an increase in diffuse CO2 emissions between September 2010 and January 2012. High-CO2-flux soil gas samples have δ13C˜0‰. Using this value and other evidence from the literature we conclude that these CO2 emissions from Santorini were a mixture between CO2 sourced from magma, and CO2 released by the thermal or metamorphic breakdown of crustal limestone. We suggest that this mixing of magmatic and crustal carbonate sources may account more broadly for the typical range of δ13C values of CO2 (from ˜-4‰ to ˜+1‰) in diffuse volcanic and fumarole gas emissions around the Mediterranean, without the need to invoke unusual mantle source compositions. At Santorini a mixing model involving magmatic CO2 (with δ13C of -3±2‰ and elevated (222Rn)/CO2 ratios ˜105-106 Bqkg) and CO2 released from decarbonation of crustal limestone (with (222Rn)/CO2 ˜ 30-300 Bq kg-1, and δ13C of +5‰) can account for the δ13C and (222Rn)/CO2 characteristics of the 'high flux' gas source. This model suggests ˜60% of the carbon in the high flux deep CO2 end member is of magmatic origin. This combination of δ13C and (222Rn) measurements has

  14. Friction in volcanic environments

    Science.gov (United States)

    Kendrick, Jackie E.; Lavallée, Yan

    2016-04-01

    to eruption behaviour and during ascent magma behaves in an increasingly rock-like manner as it degasses and crystallises. This character aids the development of shear zones in the conduit, producing fault surfaces that host gouge, cataclasite and pseudotachylyte and which control the last hundreds of meters of ascent by frictional slip. Recent work has shown that the occurrence of vesiculation of gas bubbles modifies the rheology of frictional melt and in extreme cases can trigger eruption style to switch from effusive to explosive activity. Hence it is of vital importance to recognise the frictional behaviour of volcanic rocks and magmas to understand the continuation of an eruption and associated hazards.

  15. Three-dimensional architecture and development of Danianbryozoan mounds at Limhamn, south-west Sweden, usingground-penetrating radar

    DEFF Research Database (Denmark)

    Nielsen, Lars; Schack von Brockdorff, A.; Bjerager, Morten Gustav Erik

    2009-01-01

    of larger mounds. The outermost beds of the individual mounds are commonly characterized by sub-parallel to parallel reflections which have a circular to slightly oval appearance in map view. The mounds are mainly aggrading and do not show clear signs of pronounced lateral migration during growth, although...

  16. Global volcanic emissions: budgets, plume chemistry and impacts

    Science.gov (United States)

    Mather, T. A.

    2012-12-01

    Over the past few decades our understanding of global volcanic degassing budgets, plume chemistry and the impacts of volcanic emissions on our atmosphere and environment has been revolutionized. Global volcanic emissions budgets are needed if we are to make effective use of regional and global atmospheric models in order to understand the consequences of volcanic degassing on global environmental evolution. Traditionally volcanic SO2 budgets have been the best constrained but recent efforts have seen improvements in the quantification of the budgets of other environmentally important chemical species such as CO2, the halogens (including Br and I) and trace metals (including measurements relevant to trace metal atmospheric lifetimes and bioavailability). Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents and during electrical discharges in ash-rich volcanic plumes. These reactive trace species have important consequences for gas plume chemistry and impacts, for example, in terms of the global fixed nitrogen budget, volcanically induced ozone destruction and particle fluxes to the atmosphere. Volcanically initiated atmospheric chemistry was likely to have been particularly important before biological (and latterly anthropogenic) processes started to dominate many geochemical cycles, with important consequences in terms of the evolution of the nitrogen cycle and the role of particles in modulating the Earth's climate. There are still many challenges and open questions to be addressed in this fascinating area of science.

  17. Chapter 2: 2003 Geologic Assessment of Undiscovered Conventional Oil and Gas Resources in the Upper Cretaceous Navarro and Taylor Groups, Western Gulf Province, Texas

    Science.gov (United States)

    Condon, S.M.; Dyman, T.S.

    2006-01-01

    folds, and combinations of these. Seals consist of interbedded shales and mudstones and diagenetic cementation. The area assessed is divided into five assessment units (AUs): (1) Travis Volcanic Mounds Oil (AU 50470201), (2) Uvalde Volcanic Mounds Gas and Oil (AU 50470202), (3) Navarro-Taylor Updip Oil and Gas (AU 50470203), (4) Navarro-Taylor Downdip Gas and Oil (AU 50470204), and (5) Navarro-Taylor Slope-Basin Gas (AU 50470205). Total estimated mean undiscovered conventional resources in the five assessment units combined are 33.22 million barrels of oil, 1,682.80 billion cubic feet of natural gas, and 34.26 million barrels of natural gas liquids.

  18. Thérèse Mound: a case study of coral bank development in the Belgica Mound Province, Porcupine Seabight

    Science.gov (United States)

    de Mol, Ben; Kozachenko, Max; Wheeler, Andy; Alvares, Hugo; Henriet, Jean-Pierre; Olu-Le Roy, Karine

    2007-02-01

    High-resolution seismic profiles, swath bathymetry, side-scan sonar data and video imageries are analysed in this detailed study of five carbonate mounds from the Belgica mound province with special emphasis on the well-surveyed Thérèse Mound. The selected mounds are located in the deepest part of the Belgica mound province at water depths of 950 m. Seismic data illustrate that the underlying geology is characterised by drift sedimentation in a general northerly flowing current regime. Sigmoidal sediment bodies create local slope breaks on the most recent local erosional surface, which act as the mound base. No preferential mound substratum is observed, neither is there any indication for deep geological controls on coral bank development. Seismic evidence suggests that the start-up of the coral bank development was shortly after a major erosional event of Late Pliocene Quaternary age. The coral bank geometry has been clearly affected by the local topography of this erosional base and the prevailing current regime. The summits of the coral banks are relatively flat and the flanks are steepest on their upper slopes. Deposition of the encased drift sequence has been influenced by the coral bank topography. Sediment waves are formed besides the coral banks and are the most pronounced bedforms. These seabed structures are probably induced by bottom current up to 1 m/s. Large sediment waves are colonised by living corals and might represent the initial phase of coral bank development. The biological facies distribution of the coral banks illustrate a living coral cap on the summit and upper slope and a decline of living coral populations toward the lower flanks. The data suggest that the development of the coral banks in this area is clearly an interaction between biological growth processes and drift deposition both influenced by the local topography and current regime.

  19. Concordance in mate choice in female mound-building mice.

    Science.gov (United States)

    Beigneux, Emilie; Féron, Christophe; Gouat, Patrick

    2012-03-01

    Females must evaluate male quality to perform mate choice. Since females generally base their selection on different male features, individual females may differ in their choice. In this study, we show that concordance between females in mate choice decisions may arise without any experimental maximization of a particular attractive trait. Choice tests were performed in mound-building mice, Mus spicilegus, a monogamous species. Body odours of two male donors were presented to 12 female subjects individually. To determine female choice, the same pair of males was presented three times to a female. Four different pairs of male body odours were used. Male donors, not related to females, were selected at random in our polymorphic breeding stock. Using this two-way choice design, female mice displayed a clear choice and had a similar preference for particular males.

  20. Wave Induced Loading and Stability of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Hald, Tue

    conducting model tests very large variability in e.g. the degree of stability is observed. This background motivated the investigations conducted in the present study. The objective was to investigate and clarify which wave parameters are important for the hydraulic stability of the armour layer on typical...... related to the hydraulic stability was discussed. Further, governing parameters influencing the stability were identified and their influence quantified to retrieve the state- of-the-art. Model tests were conducted at SINTEF with scale models of prototype breakwaters and both the wave induced loading......The present state of knowledge when designing coastal structures has improved in the recent years. However the available design methods concerning especially rubble mound structures are characterized by a number of empirical and semi-empirical formulae making model tests inevitable and even when...

  1. The occurrence and development of peat mounds on King George Island (Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    Jerzy Fabiszewski

    2014-02-01

    Full Text Available On King George Island, South Shetlands Islands, a type of peat formation has been discovered which has not previously been reported from the Antarctic. These formations are in shape of mounds up to 7x 15 m in area, with a peat layer of about I m thick. About twenty five cm below the surface there is a layer of permanently frozen peat. The mounds are covered by living mosses (Polytrichum alpinum and Drepanocladus uncinatus, Antarctic hair grass (Deschampsia antarctica and lichens. Erosion fissures occurring on the surface are evidence of contemporary drying and cessation of the mound's growth. The initial phase of the development of the mounds began with a community dominated by Calliergidium austro-stramineum and Deschampsia antarctica, and their further development has been due to peat accumulation formed almost entirely by Calliergidium. The location of the mounds is near a penguin rookery, which clearly conditioned the minerotrophic character of these formations, as compared with the "moss peat banks" formed by Chorisodontium aciphyllum and Polytrichum al-pestre. Moreover, the peat mounds differ from the latter in several ways, e.g. rate of growth and floristic composition. Radiocarbon dating of peat from the base of one mound gave an age of 4090±60 years B.P. This suggests that the age of the tundra on King George Island is about 5000-4000 years.

  2. Distribution and characteristics of volcanic reservoirs in China

    Institute of Scientific and Technical Information of China (English)

    HUANG Yulong; WANG Pujun; CHEN Shuming

    2009-01-01

    About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime.

  3. 40Ar/39Ar dating of Quaternary volcanic ashes by multi-collection noble gas mass spectrometry: protocols, precision and intercalibration

    DEFF Research Database (Denmark)

    Storey, Michael; Rivera, Tiffany; Flude, Stephanie

    where potassium-bearing phenocrysts may contain relatively small amounts of radiogenic 40Ar. In 2005, the Quaternary Dating Laboratory, Roskilde University, installed a Nu-Instruments multi-collector Noblesse noble gas mass spectrometer, which is configured with a Faraday detector and three ion...

  4. Deep sea corals and carbonate mounds of the nw european margin: a biogeochemical perspective

    Science.gov (United States)

    Kiriakoulakis, K.; White, M.; Bett, B.; Wolff, G. A.

    2003-04-01

    The deep-sea, scleractinian, reef-forming coral Lophelia pertusa is widespread along the NW European Continental Margin and its presence has been documented since the 19th century. However little is known about its ecology, biochemistry and particularly its relationship with the carbonate mounds it is often associated with. The characterisation of particulate organic matter (POM), which fuels the Lophelia pertusa ecosystems and the sediments on and around the coral/mound sites, may potentially shed light on the biogeochemical processes of the deep water coral (DWC) ecosystems. In this study, POM (20--40 m above bottom) and sediments have been collected from five mound/coral sites along the European Continental Slope (water depth ˜500--1000 m) with distinct oceanographic and sedimentological conditions, (Darwin, Logachev, Pelagia, Hovland and Belgica Mounds located around the Rockall Trough and Porcupine Seabight). Coral densities and mound sizes, shapes and conditions vary significantly from site to site. POM at these sites are significantly different, particularly with respect to the lipid concentrations relative to organic carbon, which are much higher at the Darwin Mounds (N.Rockall Trough; ˜1000m depth) than the rest of the sites (46.63 -- 225.11 mg g-1 and 0.49 -- 14.21 mg g-1 respectively). Polyunsaturated fatty acids (PUFAs), which are used as proxies of labile organic matter are also abundant at the Darwin Mounds, indicating that POM is 'fresh'. Scanning electron microscopy carried out on filtered material from this area confirms this. These mounds are affected by a branch of the poleward slope current, which, in combination with enhanced Ekman downwelling, could transport appreciable amounts of high quality organic matter to the depth that they are found. Lipid (including PUFAs) concentrations at the Pelagia Mounds (SE Rockall Trough; ˜700 m) although lower than at the Darwin Mounds are higher than at the other sites. This location is also influenced by

  5. Stability of Monolithic Rubble Mound Breakwater Crown Walls Subjected to Impulsive Loading

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Harck; Andersen, Lars Vabbersgaard; Andersen, Thomas Lykke

    2012-01-01

    model tests. The outcome is a more reliable evaluation of the applicability of simple dynamic calculations for the estimation of sliding distances of rubble mound superstructures. This is of great practical importance since many existing rubble mound crown walls are subjected to increasing wave loads......This paper evaluates the validity of a simple onedimensional dynamic analysis as well as a FEM model to determine the sliding of a rubble mound breakwater crown wall. The evaluation is based on a case example with real wave load time series and displacements measured from two-dimensional physical...

  6. Evidence from acoustic imaging for submarine volcanic activity in 2012 off the west coast of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen

    2014-12-01

    We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge

  7. Applications of dip angle and coherence attributes to recognition of volcanic edifice in Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of the shape and inner structure of volcanic edifice, the dip angle and coherence were selected to recognize the buried volcanic edifices in Songliao Basin. Five volcanic edifices were recognized in both two methods in the first volcanic cycle of Yingcheng Formation and the prediction perfectly corresponds to the drilling results in well XS8 area. The results are satisfying when the prediction method were employed in the exploration and development of Qingshen gas field.

  8. Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

    Science.gov (United States)

    Niles, P. B.; Michalski, J.; Edwards, C. S.

    2014-01-01

    High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits.

  9. Spatial Vegetation Data for Effigy Mounds National Monument Vegetation Mapping Project

    Data.gov (United States)

    National Park Service, Department of the Interior — The vegetation spatial database coverage (vegetation map) is a product of the Effigy Mounds National Monument Vegetation Mapping Project, USGS-NPS Vegetation Mapping...

  10. Multiple sets of information synthesized to describe fractures of volcanic reservoir: Taking volcanic reservoir of the Member 1 of Yingcheng Formation in Xudong Area of Xushen Gas Field as an example.%多信息综合火山岩储层裂缝表征:以徐深气田徐东地区营城组一段火山岩储层为例

    Institute of Scientific and Technical Information of China (English)

    陈欢庆; 胡永乐; 靳久强; 冉启全; 王拥军

    2011-01-01

    从成因角度将徐深气田徐东地区营城组一段火山岩储层裂缝划分为构造裂缝、冷凝收缩裂缝、炸裂缝、溶蚀裂缝、缝合缝、风化裂缝等多种类型.根据动静结合的思路,综合岩心、镜下薄片、常规和FMI测井资料、地震等多信息以及地震相干分析和蚂蚁追踪等技术.对各类型裂缝发育特征进行详细表征.结果表明,上述井震资料的结合可以完成火山岩储层裂缝表征,宏观上沿着徐东地区徐中断裂和徐东断裂裂缝最为发育,大致呈近SN向展布.微观上在发育SN向靠近断裂带裂缝的同时,还发育众多EW向或近EW向的裂缝.对裂缝成因机制分析,研究区目的层火山岩储层裂缝成因影响因素包括构造作用、火山岩性、火山岩体、火山岩相和成岩作用等,其中以构造作用和成岩作用为主.%The volcanic reservoir fractures of the Member 1 of Yingcheng Formation in Xudong Area of Xushen Gas Field are divided according to their origins into tectonic fractures, condensation contracted fractures, exploded fractures, corrosion fractures, stitched fractures and weathering fractures. Synthesizing multiple sets of information from cores, microsections and FMI logging data and using seismic variance and ant tracking technology, we described the characteristics of all kinds of fractures in detail. The results indicated that fractures developed along Xuzhong Faults and Xudong Faults in NS direction in macroscopic view. And many fractures developed along EW direction in microcosmic view at the same time. The analysis of genetic mechanisms of fractures suggested that the fractures of volcanic reservoir of the Member 1 of Yingcheng in Xudong Area of Xushen Gas Field were affected by tectonic processes, volcanic lithology, volcanic bodies, volcanic lithofacies and diagenesis, among which tectonic processes and diagenesis played the leading role.

  11. Volcanic hazards of the Idaho National Engineering Laboratory and adjacent areas

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, W.R. [WRH Associates, Salt Lake City, UT (United States); Smith, R.P. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)

    1994-12-01

    Potential volcanic hazards are assessed, and hazard zone maps are developed for the Idaho National Engineering Laboratory (INEL) and adjacent areas. The basis of the hazards assessment and mapping is the past volcanic history of the INEL region, and the apparent similarity of INEL volcanism with equivalent, well-studied phenomena in other regions of active volcanism, particularly Hawaii and Iceland. The most significant hazards to INEL facilities are associated with basaltic volcanism, chiefly lava flows, which move slowly and mainly threaten property by inundation or burning. Related hazards are volcanic gases and tephra, and ground disturbance associated with the ascent of magma under the volcanic zones. Several volcanic zones are identified in the INEL area. These zones contain most of the volcanic vents and fissures of the region and are inferred to be the most probable sites of future INEL volcanism. Volcanic-recurrence estimates are given for each of the volcanic zones based on geochronology of the lavas, together with the results of field and petrographic investigations concerning the cogenetic relationships of INEL volcanic deposits and associated magma intrusion. Annual probabilities of basaltic volcanism within the INEL volcanic zones range from 6.2 {times} 10{sup {minus}5} per year (average 16,000-year interval between eruptions) for the axial volcanic zone near the southern INEL boundary and the Arco volcanic-rift zone near the western INEL boundary, to 1 {times} 10{sup {minus}5} per year (average 100,000-year interval between eruptions) for the Howe-East Butte volcanic rift zone, a geologically old and poorly defined feature of the central portion of INEL. Three volcanic hazard zone maps are developed for the INEL area: lava flow hazard zones, a tephra (volcanic ash) and gas hazard zone, and a ground-deformation hazard zone. The maps are useful in land-use planning, site selection, and safety analysis.

  12. Water fluxes between inter-patches and vegetated mounds in flat semiarid landscapes

    Science.gov (United States)

    Rossi, María J.; Ares, Jorge O.

    2017-03-01

    It has been assumed that bare soil (BS) inter-patches in semi arid spotted vegetation behave as sources of water to near vegetated soil (VS) patches. However, little evidence has been gained from direct measurements of overland and infiltration water fluxes between bare soil inter-patches and shrub mounds at a scale compatible with available high resolution imagery and hydrological modeling techniques. The objective of this study is to address the thin scale internal redistribution of water between BS inter-patches and vegetated mounds at relatively flat spotted semiarid landscapes. The relation between plant cover, topography and runoff was inspected with non-parametric association coefficients based on high resolution remotely sensed imagery, ground truth topographic elevation and spatial-explicit field data on potential runoff. Measurements of advective flows at the same spatial scale were carried out at micro-plots of BS and shrub mounds. Water fluxes between BS inter-patch and a shrub mound were simulated under varying typical Patagonian rainfall scenarios with an hydrological model. Results obtained revealed that the soil properties, infiltration and overland flow metrics at the mounds and inter-patches exhibit spatially and dynamic variable hydraulic properties. High micro-topographic roughness and depression storage thickened overland flow depth at VS patches. At BS inter-patches prevailing low slopes and depression storage were found to be important variables attenuating the surface runoff. At both rainfall scenarios simulated, the soil under the shrub mound accumulated more moisture (from direct rain) and reached saturation long before this occurred in BS nearby inter-patch area. Overland flow at the inter-patch was attenuated as it reached the border of the patch, diverging from the latter as it followed the (small) topographic gradient. The overland flow generated inside the vegetated mound was effectively retained at the typical Summer rainfall

  13. Archaeological mounds as analogs of engineered covers for waste disposal sites: Literature review and progress report. [Appendix contains bibliography and data on archaeological mounds

    Energy Technology Data Exchange (ETDEWEB)

    Chatters, J C; Gard, H A

    1991-09-01

    Closure caps for low-level radioactive waste disposal facilities are typically designed as layered earthen structures, the composition of which is intended to prevent the infiltration of water and the intrusion of the public into waste forms. Federal regulations require that closure caps perform these functions well enough that minimum exposure guidelines will be met for at least 500 years. Short-term experimentation cannot mimic the conditions that will affect closure caps on the scale of centuries, and therefore cannot provide data on the performance of cap designs over long periods of time. Archaeological mounds hundreds to thousands of years old which are closely analogous to closure caps in form, construction details, and intent can be studied to obtain the necessary understanding of design performance. Pacific Northwest Laboratory conducted a review and analysis of archaeological literature on ancient human-made mounds to determine the quality and potential applicability of this information base to assessments of waste facility design performance. A bibliography of over 200 English-language references was assembled on mound structures from the Americas, Europe, and Asia. A sample of these texts was read for data on variables including environmental and geographic setting, condition, design features, construction. Detailed information was obtained on all variables except those relating to physical and hydrological characteristics of the mound matrix, which few texts presented. It is concluded that an extensive amount of literature and data are available on structures closely analogous to closure caps and that this information is a valuable source of data on the long-term performance of mounded structures. Additional study is recommended, including an expanded analysis of design features reported in the literature and field studies of the physical and hydraulic characteristics of different mound designs. 23 refs., 10 figs., 12 tabs.

  14. Buried Cold-Water Coral Mound Provinces and Contourite Drifts Along the Eastern Atlantic Margin: Controls, Interactions and Connectivity

    Science.gov (United States)

    Van Rooij, D.; Vandorpe, T.; Delivet, S.; Hebbeln, D.; Wienberg, C.; Martins, I.

    2014-12-01

    The association between cold-water coral mounds and contourite drift deposits has been demonstrated in the Belgica mound province, off Ireland. On that location, IODP expedition 307 was able to drill through the base of a mound, dating mound initiation at 2.65 Ma. However, the Belgica mounds are just one of the many expressions of mound growth. More enigmatic is the buried Magellan mound province, located in the northern part of the Porcupine Basin, featuring over 1000 relatively closely spaced buried mounds, which are all rooted on a common reflector. This indicates a common start-up event, but the true driving forces behind their initial settling, growth and demise are still unknown. The influence of bottom currents cannot be ruled out, since clear obstacle marks are present surrounding the mounds. In 2013, some 3000 km south of the Magellan mounds, a new province of buried mounds was discovered along the Moroccan Atlantic Margin, which may shed new light on the "life" cycle of mounds. Here, we report the preliminary results and propose a first view on the controls, interactions and connectivity between these 2 provinces, assisted by a series of studies of contourite drifts along the Eastern Atlantic Margin. The newly discovered buried mounds can be associated to a vast province of several clusters of seabed mounds. They occur in water depths between 500 and 1000 m, buried under up to 50 m of sediment. With respect to the Magellan mounds, they are smaller, but more importantly, they do not root on one single stratigraphic level. At least 4 different initiation levels were identified. The off-mound reflectors indicate a slight influence of bottom currents, since the mounds are located in a large sediment drift. Moreover, the link between the two buried mound provinces may be found in connecting the evolution of the associated contourite drift systems, respectively in Porcupine Seabight and the Gulf of Cádiz. Intermediate sites on Goban Spur and near Le Danois

  15. Introduction of Partial Coefficients in the Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    After a number of large breakwaters had failed or suffered severe damage, a working group established by PIANC's Permanent Technical Committee ΙΙ produced a report on the stability of rubble mound structures.......After a number of large breakwaters had failed or suffered severe damage, a working group established by PIANC's Permanent Technical Committee ΙΙ produced a report on the stability of rubble mound structures....

  16. Active hydrothermal and non-active massive sulfide mound investigation using a new multiparameter chemical sensor

    Science.gov (United States)

    Han, C.; Wu, G.; Qin, H.; Wang, Z.

    2012-12-01

    Investigation of active hydrothermal mound as well as non-active massive sulfide mound are studied recently. However, there is still lack of in-situ detection method for the non-active massive sulfide mound. Even though Transient ElectroMagnetic (TEM) and Electric Self-potential (SP) methods are good, they both are labour, time and money cost work. We proposed a new multiparameter chemical sensor method to study the seafloor active hydrothermal mound as well as non-active massive sulfide mound. This sensor integrates Eh, S2- ions concentration and pH electrochemical electrodes together, and could found chemical change caused by the active hydrothermal vent, even weak chemical abnormalities by non-active massive sulfide hydrothermal mound which MARP and CTD sometimes cannot detect. In 2012, the 1st Leg of the Chinese 26th cruise, the multiparameter chemical sensor was carried out with the deepsea camera system over the Carlsberg Ridge in Indian Ocean by R/V DAYANGYIHAO. It was shown small Eh and S2- ions concentration abnormal around a site at Northwest Indian ridge. This site was also evidenced by the TV grab. In the 2nd Leg of the same cruise in June, this chemical sensor was carried out with TEM and SP survey system. The chemical abnormalities are matched very well with both TEM and SP survey results. The results show that the multiparameter chemical sensor method not only can detect active hydrothermal mound, but also can find the non-active massive sulfide hydrothermal mound.

  17. Introduction of Partial Coefficients in the Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    1992-01-01

    After a number of large breakwaters had failed or suffered severe damage, a working group established by PIANC's Permanent Technical Committee ΙΙ produced a report on the stability of rubble mound structures.......After a number of large breakwaters had failed or suffered severe damage, a working group established by PIANC's Permanent Technical Committee ΙΙ produced a report on the stability of rubble mound structures....

  18. Volcanic air pollution hazards in Hawaii

    Science.gov (United States)

    Elias, Tamar; Sutton, A. Jeff

    2017-04-20

    Noxious sulfur dioxide gas and other air pollutants emitted from Kīlauea Volcano on the Island of Hawai‘i react with oxygen, atmospheric moisture, and sunlight to produce volcanic smog (vog) and acid rain. Vog can negatively affect human health and agriculture, and acid rain can contaminate household water supplies by leaching metals from building and plumbing materials in rooftop rainwater-catchment systems. U.S. Geological Survey scientists, along with health professionals and local government officials are working together to better understand volcanic air pollution and to enhance public awareness of this hazard.

  19. Numerical Modelling of Solitary Wave Experiments on Rubble Mound Breakwaters

    Science.gov (United States)

    Guler, H. G.; Arikawa, T.; Baykal, C.; Yalciner, A. C.

    2016-12-01

    Performance of a rubble mound breakwater protecting Haydarpasa Port, Turkey, has been tested under tsunami attack by physical model tests conducted at Port and Airport Research Institute (Guler et al, 2015). It is aimed to understand dynamic force of the tsunami by conducting solitary wave tests (Arikawa, 2015). In this study, the main objective is to perform numerical modelling of solitary wave tests in order to verify accuracy of the CFD model IHFOAM, developed in OpenFOAM environment (Higuera et al, 2013), by comparing results of the numerical computations with the experimental results. IHFOAM is the numerical modelling tool which is based on VARANS equations with a k-ω SST turbulence model including realistic wave generation, and active wave absorption. Experiments are performed using a Froude scale of 1/30, measuring surface elevation and flow velocity at several locations in the wave channel, and wave pressure around the crown wall of the breakwater. Solitary wave tests with wave heights of H=7.5 cm and H=10 cm are selected which represent the results of the experiments. The first test (H=7.5 cm) is the case that resulted in no damage whereas the second case (H=10 cm) resulted in total damage due to the sliding of the crown wall. After comparison of the preliminary results of numerical simulations with experimental data for both cases, it is observed that solitary wave experiments could be accurately modeled using IHFOAM focusing water surface elevations, flow velocities, and wave pressures on the crown wall of the breakwater (Figure, result of sim. at t=29.6 sec). ACKNOWLEDGEMENTSThe authors acknowledge developers of IHFOAM, further extend their acknowledgements for the partial supports from the research projects MarDiM, ASTARTE, RAPSODI, and TUBITAK 213M534. REFERENCESArikawa (2015) "Consideration of Characteristics of Pressure on Seawall by Solitary Waves Based on Hydraulic Experiments", Jour. of Japan. Soc. of Civ. Eng. Ser. B2 (Coast. Eng.), Vol 71, p I

  20. The Surales, Self-Organized Earth-Mound Landscapes Made by Earthworms in a Seasonal Tropical Wetland.

    Science.gov (United States)

    Zangerlé, Anne; Renard, Delphine; Iriarte, José; Suarez Jimenez, Luz Elena; Adame Montoya, Kisay Lorena; Juilleret, Jérôme; McKey, Doyle

    2016-01-01

    The formation, functioning and emergent properties of patterned landscapes have recently drawn increased attention, notably in semi-arid ecosystems. We describe and analyze a set of similarly spectacular landforms in seasonal tropical wetlands. Surales landscapes, comprised of densely packed, regularly spaced mounds, cover large areas of the Orinoco Llanos. Although descriptions of surales date back to the 1940's, their ecology is virtually unknown. From data on soil physical and chemical properties, soil macrofauna, vegetation and aerial imagery, we provide evidence of the spatial extent of surales and how they form and develop. Mounds are largely comprised of earthworm casts. Recognizable, recently produced casts account for up to one-half of total soil mass. Locally, mounds are relatively constant in size, but vary greatly across sites in diameter (0.5-5 m) and height (from 0.3 m to over 2 m). This variation appears to reflect a chronosequence of surales formation and growth. Mound shape (round to labyrinth) varies across elevational gradients. Mounds are initiated when large earthworms feed in shallowly flooded soils, depositing casts that form 'towers' above water level. Using permanent galleries, each earthworm returns repeatedly to the same spot to deposit casts and to respire. Over time, the tower becomes a mound. Because each earthworm has a restricted foraging radius, there is net movement of soil to the mound from the surrounding area. As the mound grows, its basin thus becomes deeper, making initiation of a new mound nearby more difficult. When mounds already initiated are situated close together, the basin between them is filled and mounds coalesce to form larger composite mounds. Over time, this process produces mounds up to 5 m in diameter and 2 m tall. Our results suggest that one earthworm species drives self-organizing processes that produce keystone structures determining ecosystem functioning and development.

  1. Molluskan fauna in two shell mounds in the State of Parana coast, Brazil

    Directory of Open Access Journals (Sweden)

    Marcos de Vasconcellos Gernet

    2011-09-01

    Full Text Available The shell mounds are artificial formations consisting mostly of mollusk shells used in the feeding of the prehistoric peoples which inhabited our coast. These sites are found throughout the Brazilian coast, and hundreds of them were cataloged in the State of Paraná since the 1940s. The fragility of these sites, their importance as evidences of our prehistoric period, and its abrupt disappearance, justify the need for new researches which contribute to contextualize and draw up plans to preserve this heritage. The works related to the molluskan fauna found in the shell mounds are restricted to refer to the most common species and, sometimes, just their popular names. A greater knowledge on these prehistoric inhabitants’ diet allows a better understanding of ancient natural ecosystems. The survey of mollusks was carried out in the shell mounds Guaraguaçu and Boguaçu, in the towns of Pontal do Parana and Guaratuba, respectively, and performed through visual inspection, reading of specialized bibliography and comparison to previous works on the fauna of the shell mounds in the State of Parana coast. Altogether, 29 species were observed in the shell mound Guaraguaçu and 17 species were observed in the shell mound Boguaçu, resulting in a total of 31 species.

  2. Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea)

    KAUST Repository

    Wang, Yong

    2015-10-20

    In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin.

  3. Oil reservoirs in grainstone aprons around Bryozoan Mounds, Upper Harrodsburg Limestone, Mississippian, Illinois Basin

    Energy Technology Data Exchange (ETDEWEB)

    Jobe, H. [UNOCAL Energy Resources, Sugar Land, TX (United States); Saller, A. [UNOCAL Energy Resources, Brea, CA (United States)

    1995-06-01

    Several oil pools have been discovered recently in the upper Harrodsburg Limestone (middle Mississippian) of the Illinois basin. A depositional model for bryozoan mound complexes has allowed more successful exploration and development in this play. In the Johnsonville area of Wayne County, Illinois, three lithofacies are dominant in the upper Harrodsburg: (1) bryozoan boundstones, (2) bryozoan grainstones, and (3) fossiliferous wackestones. Bryozoan boundstones occur as discontinuous mounds and have low porosity. Although bryozoan boundstones are not the main reservoir lithofacies, they are important because they influenced the distribution of bryozoan grainstones and existing structure. Bryozoan grainstones have intergranular porosity and are the main reservoir rock. Bryozoan fragments derived from bryozoan boundstone mounds were concentrated in grainstones around the mounds. Fossiliferous wackestones are not porous and form vertical and lateral seals for upper Harrodsburg grainstones. Fossiliferous wackestones were deposited in deeper water adjacent to bryozoan grainstone aprons, and above grainstones and boundstones after the mounds were drowned. Upper Harrodsburg oil reservoirs occur where grainstone aprons are structurally high. The Harrodsburg is a good example of a carbonate mound system where boundstone cores are not porous, but adjacent grainstones are porous. Primary recovery in these upper Harrodsburg reservoirs is improved by strong pressure support from an aquifer in the lower Harrodsburg. Unfortunately, oil production is commonly decreased by water encroaching from that underlying aquifer.

  4. Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea.

    Directory of Open Access Journals (Sweden)

    Yong Wang

    Full Text Available In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin.

  5. The Role of Benthic Currents and Sediment Transport On Deep-water Coral Mound Morphology and Growth: Examples From The Belgica and Moira Mounds, Eastern Porcupine Seabight, NE Atlantic

    Science.gov (United States)

    Wheeler, A.; Kozachenko, M.; Olu-Le Roy, K.

    Deep-water corals and associated carbonate mound build-ups are extensive along the European continental margin coincident with areas of strong benthic current activity and, often, regions of active sand transport. Although as yet unsubstantiated links to hydrocarbon seepage may play a defining role in the generation of carbonate mounds, the growth of mounds is strongly influenced by benthic current activity. Furthermore, the morphology of mounds, both in terms of their overall shape and surface morpho- logical features, is strongly dictated by the benthic-currents. Giant carbonate mounds, e.g. the Thérèse Mound, Belgica Mound province, eastern Porcupine Seabight, NE Atlantic, show upstream growth (through biological and sed- imentary accretion) with downstream scour and sediment starvation influencing their overall morphology. The surface morphological details of these giant mounds show distinct relationships to sediment waves that have become colonised and stabilised by coral and associated communities. Once colonised, the sandwave surface-morphology is mimic by biological growth with corals preferential growing on wave crests, taking advantage of stronger current and nutrient flux, to form coral banks. Furthermore, erosion of carbonate mounds by strong current activity exposes suitable hard substrates for further coral colonisation. Paradoxically therefore, mound erosion stimulates further coral growth illustrating another benthic-current control on mound growth. The Moira Mounds in the Belgica Mound Province, Porcupine Seabight are small coral-colonised mound features (tens of metres across and a few metres high) that represent an early stage of mound development and much younger then their giant carbonate mound counterparts. These features occur in areas of active sand transport, on rippled sand sheets and the upstream margins of sediment wave fields. Once coral colonies gained a SfootingT in these areas, coral colonies trap sand and build posi- & cedil; 1

  6. Evidence of volcanic and glacial activity in Chryse and Acidalia Planitiae, Mars

    Science.gov (United States)

    Martinez-Alonso, Sara; Mellon, Michael T.; Banks, Maria E.; Keszthelyi, Laszlo P.; McEwen, Alfred S.

    2011-01-01

    Chryse and Acidalia Planitiae show numerous examples of enigmatic landforms previously interpreted to have been influenced by a water/ice-rich geologic history. These landforms include giant polygons bounded by kilometer-scale arcuate troughs, bright pitted mounds, and mesa-like features. To investigate the significance of the last we have analyzed in detail the region between 60°N, 290°E and 10°N, 360°E utilizing HiRISE (High Resolution Imaging Science Experiment) images as well as regional-scale data for context. The mesas may be analogous to terrestrial tuyas (emergent sub-ice volcanoes), although definitive proof has not been identified. We also report on a blocky unit and associated landforms (drumlins, eskers, inverted valleys, kettle holes) consistent with ice-emplaced volcanic or volcano-sedimentary flows. The spatial association between tuya-like mesas, ice-emplaced flows, and further possible evidence of volcanism (deflated flow fronts, volcanic vents, columnar jointing, rootless cones), and an extensive fluid-rich substratum (giant polygons, bright mounds, rampart craters), allows for the possibility of glaciovolcanic activity in the region.Landforms indicative of glacial activity on Chryse/Acidalia suggest a paleoclimatic environment remarkably different from today's. Climate changes on Mars (driven by orbital/obliquity changes) or giant outflow channel activity could have resulted in ice-sheet-related landforms far from the current polar caps.

  7. Biogeochemistry and geomicrobiology of cold-water coral carbonate mounds - lessons learned from IODP Expedition 307

    Science.gov (United States)

    Ferdelman, Timothy; Wehrmann, Laura; Mangelsdorf, Kai; Kano, Akihiro; Williams, Trevor; Jean-Pierre, Henriet

    2010-05-01

    Large mound structures associated with cold-water coral ecosystems commonly occur on the slopes of continental margins, for instance, west of Ireland in the Porcupine Seabight, the Gulf of Cadiz or the Straits of Florida. In the Porcupine Seabight over 1500 mounds of up to 5 km in diameter and 250 m height lie at water depths of 600 to 900 m. The cold-water coral reef ecosystems associated with these structures are considered to be "hotspots" of organic carbon mineralization and microbial systems. To establish a depositional and biogeochemical/diagenetic model for cold-water carbonate mounds, Challenger Mound and adjacent continental slope sites were drilled in May 2005 during IODP Expedition 307. One major objective was to test whether deep sub-surface hydrocarbon flow and enhanced microbial activity within the mound structure was important in producing and stabilizing these sedimentary structures. Drilling results showed that the Challenger mound succession (IODP Site U1317) is 130 to 150 meters thick, and mainly consists of floatstone and rudstone facies formed of fine sediments and cold-water branching corals. Pronounced recurring cycles on the scales of several meters are recognized in carbonate content (up to 70% carbonate) and color reflectance, and are probably associated with Pleistocene glacial-interglacial cycles. A role for methane seepage and subsequent anaerobic oxidation was discounted both as a hard-round substrate for mound initiation and as a principal source of carbonate within the mound succession. A broad sulfate-methane transition (approximately 50 m thick)within the Miocene sediments suggested that the zone of anaerobic oxidation of methane principally occurs below the moundbase. In the mound sediments, interstitial water profiles of sulfate, alkalinity, Mg, and Sr suggested a tight coupling between carbonate diagenesis and low rates of microbial sulfate reduction. Overall organic carbon mineralization within cold-water coral mound appeared

  8. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  9. Bryan Mound SPR cavern 113 remedial leach stage 1 analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Rudeen, David Keith; Weber, Paula D.; Lord, David L.

    2013-08-01

    The U.S. Strategic Petroleum Reserve implemented the first stage of a leach plan in 2011-2012 to expand storage volume in the existing Bryan Mound 113 cavern from a starting volume of 7.4 million barrels (MMB) to its design volume of 11.2 MMB. The first stage was terminated several months earlier than expected in August, 2012, as the upper section of the leach zone expanded outward more quickly than design. The oil-brine interface was then re-positioned with the intent to resume leaching in the second stage configuration. This report evaluates the as-built configuration of the cavern at the end of the first stage, and recommends changes to the second stage plan in order to accommodate for the variance between the first stage plan and the as-built cavern. SANSMIC leach code simulations are presented and compared with sonar surveys in order to aid in the analysis and offer projections of likely outcomes from the revised plan for the second stage leach.

  10. Earth-mounded concrete bunker PLAP technical approach

    Energy Technology Data Exchange (ETDEWEB)

    Eng, R.

    1989-11-01

    Under the US DOE Prototype License Application Project (PLAP), Ebasco Services Incorporated was commissioned to develop a preliminary design of the Earth-Mounded Concrete Bunker (EMCB) concept for low-level radioactive waste (LLW) disposal. The EMCB disposal concept is of great interest because it represents the only engineered LLW disposal technology currently in use in the commercial sector. By definition, the EMCB disposal structure is located partially below grade and partially above grade. The concrete bunker is an engineered structure designed to be structurally stable for the prerequisite time horizon. The basic design parameters of the disposal facility were stipulated by US DOE, a northeast site location, representative waste, 30 year operational life, and a 250,000 ft{sup 3}/year disposal capacity. The design was developed to satisfy only US NRC Part 61 disposal requirements, not individual state requirements that may go beyond Part 61 requirements. The technical safety analysis of the preliminary design was documented according to the format specifications of NUREG-1199, to the extent practicable with quite limited resources.

  11. Photogrammetric analysis of rubble mound breakwaters scale model tests

    Directory of Open Access Journals (Sweden)

    João Rodrigues

    2016-09-01

    Full Text Available The main goal of this paper is to develop a photogrammetric method in order to obtain arobust tool for damage assessment and quantification of rubble-mound armour layers during physicalscale model tests. With the present work, an innovative approach based on a reduced number ofdigital photos is proposed to support the identification of affected areas. This work considers twosimple digital photographs recording the instants before and after the completion of the physicaltest. Mathematical techniques were considered in the development of the procedures, enabling thetracking of image differences between photos. The procedures were developed using an open-sourceapplication, Scilab, nevertheless they are not platform dependent. The procedures developed enablethe location and identity of eroded areas in the breakwater armour layer, as well as the possibilityof quantifying them. This ability is confirmed through the calculation of correlation coefficients ineach step of the search for the more damaged area. It is also possible to make an assessment of themovement of armour layer units.

  12. Earth-mounded concrete bunker PLAP technical approach

    Energy Technology Data Exchange (ETDEWEB)

    Eng, R.

    1989-11-01

    Under the US DOE Prototype License Application Project (PLAP), Ebasco Services Incorporated was commissioned to develop a preliminary design of the Earth-Mounded Concrete Bunker (EMCB) concept for low-level radioactive waste (LLW) disposal. The EMCB disposal concept is of great interest because it represents the only engineered LLW disposal technology currently in use in the commercial sector. By definition, the EMCB disposal structure is located partially below grade and partially above grade. The concrete bunker is an engineered structure designed to be structurally stable for the prerequisite time horizon. The basic design parameters of the disposal facility were stipulated by US DOE, a northeast site location, representative waste, 30 year operational life, and a 250,000 ft{sup 3}/year disposal capacity. The design was developed to satisfy only US NRC Part 61 disposal requirements, not individual state requirements that may go beyond Part 61 requirements. The technical safety analysis of the preliminary design was documented according to the format specifications of NUREG-1199, to the extent practicable with quite limited resources.

  13. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  14. 基于三相孔隙弹性理论的火山岩气层岩石物理响应特征分析%Analysis of rock physics response of gas-bearing volcanic reservoir based on three-phase poroelastic theory

    Institute of Scientific and Technical Information of China (English)

    吴清岭; 赵海波; 李来林; 范兴才

    2008-01-01

    Unlike previous theories with velocity and/or elastic modulus averaging, we use a three-phase porous rock physics model developed by Santos for analyzing the seismic response of two immiscible fluids in saturated porous media. Considering reservoir reference pressure and coupling drag of two fluids in pores, the effects of frequency, porosity, and gas saturation on the phase velocities of the P- and S-waves are discussed in detail under field conditions. The effects of porosity and gas saturation on Vp/Vs are also provided. The data for our numerical experiments are from a sample of deep volcanic rock from Daqing. The numerical results show that the frequency dispersion effect can be ignored for deep volcanic rocks with low porosity and low permeability. It is concluded that for deep volcanic rocks the effect of gas content in pores on Vp/Vs is negligible but the effect of porosity is significant when there is a certain amount of water contained in the pores. The accurate estimate of lithology and porosity in this case is relatively more important.

  15. Noble gas isotopic ratios from historical lavas and fumaroles at Mount Vesuvius (southern Italy): constraints for current and future volcanic activity

    Science.gov (United States)

    Tedesco, Dario; Nagao, Keisuke; Scarsi, Paolo

    1998-12-01

    Helium, neon and argon isotope ratios have been analysed from phenocrysts of eleven lava samples belonging to the last eruptive cycle of Mount Vesuvius (1631 until 1944). The phenocrysts separates include pyroxene ( N=10) and olivine ( N=1). All phenocryst samples show similarly low gas contents (He, Ne and Ar ˜10 -10 cm 3/g). 3He/ 4He ratios, 5.3-2.11 Ra, are generally low if compared to those typical of the MORB and those of the European Subcontinental Mantle (ESCM), respectively R/ Ra 8.5±1 and 6.0-6.5. A decreasing trend is found from 1631 to 1796, while a more homogeneous set of data is obtained for more recent eruptions, as evidenced by an average R/ Ra value of 2.85. Neon ratios ( 21Ne/ 22Ne and 20Ne/ 22Ne) strongly differ from those typically found on volcanoes and suggest that a crustal component has been added in the source region to Mt. Vesuvius magmas. Argon ratios ( 40Ar/ 36Ar and 38Ar/ 36Ar) have values similar to the atmosphere and are well correlated. The low 40Ar/ 36Ar ratio (max. 302) is, however, in the range of the 40Ar/ 36Ar ratios obtained from several lava samples at other Italian volcanoes and might be considered to have a deep origin. Two hypothesis have been discussed: (1) a deep argon-like-air source, due to subduction of air-rich sediments and/or (2) a preferential loss of Ar, in comparison to lighter noble gases, from silicic melts. Helium isotopic analysis of gas samples recently collected from crater and submarine fumaroles are similar to those of lavas belonging to the final part of this eruptive cycle. This result supports the idea that no new juvenile fluids from the source region have been injected into the magmatic reservoir during the 1631-1944 eruptive cycle and, more importantly, until 1993. Both sets of data help to understand the genesis of these fluids and to constrain the current activity of the volcano.

  16. Science Targets in the Landing Ellipse and Lower Mound at the Gale Crater Field Site

    Science.gov (United States)

    Anderson, R. B.; Bell, J. F.

    2011-12-01

    The Mars Science Laboratory (MSL) rover Curiosity will land at the ~155 km diameter Gale Crater (4.6°S 137.2°E) in early August of 2012. The landing ellipse is centered in the northwestern floor of the crater on an alluvial fan composed of material from the crater rim. MSL will sample this material and test the hypothesis that the fan was deposited by flowing liquid water, and then drive south toward the base of the >5km tall central mound of layered rocks. Along this traverse, the smooth, low-thermal-inertia surface of the alluvial fan transitions to a fractured, layered, and spectrally neutral high thermal inertia unit. MSL will be able to assess the interpretation of this unit as cemented alluvial material and determine the cementing agent. Fresh craters in the high thermal inertia unit are important targets for MSL because their ejecta has had less exposure to the harsh radiation environment of the surface which can destroy biomarkers. Continuing south, MSL will descend across a short scarp where the units of the crater floor have eroded to expose the underlying basal unit of the mound. This erosion has formed ridged mesas interpreted to be lithified aeolian bedforms that are part of a widespread "mound-skirting" unit. MSL will test the hypothesis that this unit comprises debris shed from the mound during an early stage of erosion. The heavily fractured basal unit is partially obscured by relatively young mafic dunes, which will provide information about modern aeolian processes on Mars. After analyzing the basal unit and the dunes, MSL will begin climbing the layered rocks of the mound, beginning with a light-toned ridge which shows spectral evidence of hydrated sulfates. Beyond this ridge, the rover will encounter a phyllosilicate-bearing surface exposed in a trough paralleling the ridge. These lower mound layers are the primary targets of the MSL traverse. MSL will test the hypothesis that the lower mound sediments were deposited in a lacustrine setting

  17. Volcanic activity: a review for health professionals.

    Science.gov (United States)

    Newhall, C G; Fruchter, J S

    1986-03-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace elements composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); "mudflows" (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity.

  18. Volcanic Rocks and Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

  19. Paleoenvironmental reconstruction of deep-water carbonate mound initiation in the Porcupine Seabight, NE Atlantic

    Science.gov (United States)

    Raddatz, J.; Rüggeberg, A.; Liebetrau, V.; Margreth, S.; Eisenhauer, A.; Dullo, C.

    2009-12-01

    The understanding of the paleoenvironment during initiation and early development of deep-water carbonate mounds in the NE Atlantic is still under debate. The Integrated Ocean Drilling Program Expedition 307 sailed in 2005 to the Porcupine Seabight in order to investigate for the first time sediments from the base of a giant carbonate mound (155 m, Challenger Mound). First results indicate initiation and start-up phase of this carbonate mound coincides with the beginning of the Northern Hemisphere Glaciation (NHG) at around 2.7 Ma. Further carbonate mound development seems to be strongly dependent on rapid changes in paleoceanographic and climatic conditions at the Pliocene-Pleistocene boundary, especially characterized and caused by intermediate water masses. To investigate this specific time interval of ~2.7 Ma we use well-developed proxies such as δ18O and δ13C of planktonic (Globigerina bulloides) and a collection of benthic foraminifera (Fontbotia wuellerstorfi, Discanomalina coronata, Lobatula lobatula, Lobatula antartica, and Planulina ariminensis) as well as grain size analysis. Additionally we provide δ88/86Sr paleotemperatures from cold water coral Lophelia pertusa. This multi proxy approach made it possible to determine the paleoenvironmental and paleoecological setting favourable for the initial coral colonization. Stable oxygen and carbon isotope records of the benthic foraminiferal assemblages indicate that Lobatula lobatula provides a reliable isotopic signature for paleoenvironmental reconstructions and that enhanced bottom currents of intermediate water masses of southern origin (Mediterranean, Bay of Biscay) intensified at the start-up of the NHG. During initiation and early mound development, temperatures of these intermediate waters decreased to favourable 9 °C and reconstructed current strength and nutrient concentrations (phosphate and nitrate) stayed in the range of reported tolerance supporting the rapid growth of cold-water corals and

  20. Volcanic ash: What it is and how it forms

    Energy Technology Data Exchange (ETDEWEB)

    Heiken, G.

    1991-09-13

    There are four basic eruption processes that produce volcanic ash: (1) decompression of rising magma, gas bubble growth, and fragmentation of the foamy magma in the volcanic vent (magmatic), (2) explosive mixing of magma with ground or surface water (hydrovolcanic), (3) fragmentation of country rock during rapid expansion of steam and/or hot water (phreatic), and (4) breakup of lava fragments during rapid transport from the vent. Variations in eruption style and the characteristics of volcanic ashes produced during explosive eruptions depend on many factors, including magmatic temperature, gas content, viscosity and crystal content of the magma before eruption, the ratio of magma to ground or surface water, and physical properties of the rock enclosing the vent. Volcanic ash is composed of rock and mineral fragments, and glass shards, which is less than 2 mm in diameter. Glass shard shapes and sizes depend upon size and shape of gas bubbles present within the magma immediately before eruption and the processes responsible for fragmentation of the magma. Shards range from slightly curved, thin glass plates, which were broken from large, thin-walled spherical bubble walls, to hollow needles broken from pumiceous melts containing gas bubbles stretched by magma flow within the volcanic vent. Pumice fragments make up the coarser-grained portions of the glass fraction. Particle sizes range from meters for large blocks expelled near the volcanic vent to nanometers for fine ash and aerosol droplets within well-dispersed eruption plumes. 18 refs., 6 figs., 1 tab.

  1. Thermal vesiculation during volcanic eruptions

    Science.gov (United States)

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo

    2015-12-01

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  2. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    Science.gov (United States)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  3. Distribution and density of Cubitermes Wasmann (Isoptera: Termitidae mounds in the northern Kruger National Park

    Directory of Open Access Journals (Sweden)

    V.W. Meyer

    2000-07-01

    Full Text Available This paper provides fundamental information on distribution and density of the genus Cubitermes, Wasm. quantified for future monitoring. After distribution trends have been established, changes in Cubitermes density over time can be brought into contention with other factors in the Kruger National Park, such as the impact of fire frequency, water distribution, and elephant density on these insects. At least ten 2 ha belt-transects were undertaken in each of the 20 northern landscape zones of the KNP. Termite mounds were recorded and their activity within was determined. Cubitermes accounts for 29.8% of all active termite mounds in the northern KNP, with an average density of 0.33 mounds/ha. Cubitermes favours the Nwambiya Sandveld (zone 32. These termites occur in high density in the Klipkoppies 1 land type (Gorge, but in low densities in the Phalaborwa 10-12, Bulweni 1-3, Letaba 1-7 and Pafuri 3-6 land types. Cubitermes mounds tend to occur in high numbers on the Nzhelele formation (Mn (sandstones; quartzite; basalt. Mounds of this genus in the Far North are highly concentrated on the Gaudam and Moriah soil series of the Hutton form, suggesting that these termites prefer very sandy soils with medium to coarse particles.

  4. Environmental assessment and planning at Mound - environmental monitoring capabilities and personnel profiles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    Through its long experience with radioactive materials, Mound has developed a comprehensive, routine, offsite, environmental surveillance program to safeguard its employees, the physical plant, and the integrity of the surrounding environment from any potential adverse effects of its widely diverse operations. Effluent samples are analyzed for radiological and non-radiological parameters. The environment surrounding Mound Facility is continuously monitored - air, water, foodstuffs, vegetation, soil, and silt samples are analyzed to ensure that radioisotopic concentrations and other possible pollutants are well within the stringent standards adopted by the Department of Energy, the Environmental Protection Agencies (both federal and state), and various regional and local agencies. Moreover, this environmental surveillance program has been designed to ensure that the facility is designed, constructed, managed, operated, and maintained in a manner that continues to meet all federal, state, and local standards for environmental protection. Work in environmental science has been broadened to assess environmental factors associated with various aspects of the National Energy Plan. Both the management and staff at Mound have undertaken a firm commitment to make Mound`s environmental monitoring capabilities available to agencies that have the responsibility for the resolution of important environmental issues.

  5. [Spatial correlation of active mounds locative distribution of Solenopsis invicta Buren polygyne populations].

    Science.gov (United States)

    Lu, Yong-yue; Li, Ning-dong; Liang, Guang-wen; Zeng, Ling

    2007-01-01

    By using geostatistic method, this paper studied the spatial distribution patterns of the active mounds of Solenopsis invicta Buren polygyne populations in Wuchuan and Shenzhen, and built up the spherical models of the interval distances and semivariances of the mounds. The semivariograms were described at the two directions of east-west and south-north, which were obviously positively correlated to the interval distances, revealing that the active mounds in locative area were space-dependent. The ranges of the 5 spherical models constructed for 5 sampling plots in Wuchuan were 9.1 m, 7.6 m, 23.5 m, 7.5 m and 14.5 m, respectively, with an average of 12.4 m. The mounds of any two plots in this range were significantly correlated. There was a randomicity in the spatial distribution of active mounds, and the randomicity index (Nugget/Sill) was 0.7034, 0.9247, 0.4398, 1.1196 and 0.4624, respectively. In Shenzhen, the relationships between the interval distances and semivariances were described by 7 spherical models, and the ranges were 14.5 m, 11.2 m, 10.8 m, 17.6 m, 11.3 m, 9.9 m and 12.8 m, respectively, with an average of 12.6 m.

  6. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    Science.gov (United States)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  7. Anthropogenic relief features in tropical northern Australia: a physical and chemical analysis of the Weipa shell mounds

    Science.gov (United States)

    Fanning, Patricia; Holdaway, Simon; Allely, Kasey; Larsen, Bernie; Petchey, Fiona

    2017-04-01

    Large mounded deposits of shell are prominent archaeological features across much of the north Australian tropical coast. Many of the shell mounds are composed almost entirely of the bivalve Anadara granosa (Linnaeus 1758), a food source for Aboriginal people in the past. They are identified in the field by their distinct mounded topographic form and the unique vegetation community growing on them. A relatively long history of inquiry into the nature and significance of the shell mounds has focused primarily on analysing the shell component as clues to Australian Aboriginal coastal economies in the past. This paper presents results of new analyses on the non-shell sediments of mounds located near Weipa in far north Queensland, examining the physical and chemical signatures of depositional and post-depositional processes with a view to obtaining insights into how the mounds formed and for what purposes, and how their morphology, structure and content may have changed since they ceased accumulating. We also consider how such changes might relate to past and present environmental conditions. The mounds we studied are primarily located on topographic high points, such as cliffs, hillslopes and beach ridges, though a proportion are located on estuarine floodplains at low elevations. Terrestrial Laser Scanning (TLS) of a sample of 51 shell mounds demonstrates substantial variation in mound size and shape, and suggests patterning in mound form related to age as well as position on the landscape. However, radiocarbon chronologies demonstrate that the mounds do not conform to a model of linear formation of a shell deposit, suggesting mound histories are variable in both the nature of shell deposition as well as post-depositional processes. Soil physical and chemical analyses indicate that post-depositional diagenetic alteration has strongly influenced the present day composition and form of the shell mounds, in particular the accession of carbon and silica to the mounds by

  8. New insight from noble gas and stable isotopes of geothermal/hydrothermal fluids at Caviahue-Copahue Volcanic Complex: Boiling steam separation and water-rock interaction at shallow depth

    Science.gov (United States)

    Roulleau, Emilie; Tardani, Daniele; Sano, Yuji; Takahata, Naoto; Vinet, Nicolas; Bravo, Francisco; Muñoz, Carlos; Sanchez, Juan

    2016-12-01

    We measured noble gas and stable isotopes of the geothermal and hydrothermal fluids of the Caviahue-Copahue Volcanic Complex (CCVC), one of the most important geothermal systems in Argentina/Chile, in order to provide new insights into fluid circulation and origin. With the exception of Anfiteatro and Chancho-co geothermal systems, mantle-derived helium dominates in the CCVC fluids, with measured 3He/4He ratios up to 7.86Ra in 2015. Their positive δ15N is an evidence for subducted sediment-derived nitrogen, which is commonly observed in subduction settings. Both He-N2-Ar composition and positive correlation between δD-H2O and δ18O-H2O suggest that the fluids from Anfiteatro and Chancho-co (and partly from Pucon-Mahuida as well, on the southern flank of Copahue volcano) represent a meteoric water composition with a minor magmatic contribution. The Ne, Kr and Xe isotopic compositions are entirely of atmospheric origin, but processes of boiling and steam separation have led to fractionation of their elemental abundances. We modeled the CCVC fluid evolution using Rayleigh distillation curves, considering an initial air saturated geothermal water (ASGW) end-member at 250 and 300 °C, followed by boiling and steam separation at lower temperatures (from 200 °C to 150 °C). Between 2014 and 2015, the CCVC hydrogen and oxygen isotopes shifted from local meteoric water-dominated to andesitic water-dominated signature. This shift is associated with an increase of δ13C values and Stotal, HCl and He contents. These characteristics are consistent with a change in the gas ascent pathway between 2014 and 2015, which in turn induced higher magmatic-hydrothermal contribution in the fluid signature. The composition of the magmatic source of the CCVC fluids is: 3He/4He = 7.7Ra, δ15N = + 6‰, and δ13C = - 6.5‰. Mixing models between air-corrected He and N suggest the involvement of 0.5% to 5% of subducted sediments in the magmatic source. The magmatic sulfur isotopic

  9. High Resolution Seismic Survey off the Pacific Shore of Costa Rica - Detailed Imaging of Deformational Patterns, Fluid Venting and Carbonate Mounds

    Science.gov (United States)

    Fekete, N.; Spiess, V.; Heidersdorf, F.; v. Lom, H.; Zuehlsdorff, L.; Denil, D.; Huguen, C.; Schnabel, M.

    2003-04-01

    R/V METEOR Research Cruise M54/1 in summer 2002 from Balboa (Panama) to Caldera (Costa Rica) aimed at imaging the near sea floor sedimentary structures of both the continental and oceanic plates of the Costa Rican Subduction Zone with the high resolution seismic method. The cruise evolved from a cooperation of the Marine Seismics Group of the University of Bremen with the DFG funded Special Research Project 574 - Fluids and Volatiles in Subduction Zones - and is intended to supplement the marine geophysical, geological and geochemical as well as oceanographic data collected during R/V SONNE cruises in the area, as well as subsequent R/V METEOR cruises M54/2 and /3. The objectives of SFB 574 are the investigation of shallow and deep processes in subduction zones through near surface sampling of fluid vent sites and gas hydrate occurrences, as well as through detailed seismic and acoustic imaging of related structures. The main objectives of the cruise were to study 1) the volatile and material input into the sedimentary system on the oceanic plate, 2) the distribution of gas hydrates within the sediments, and 3) possible pathways and resulting structures of fluid/gas escape. Several working areas were selected, which had been identified as highly fractured sediment packages above subducting seamounts (Jaco Scar, Parrita Scar, Rio Bongo, Hongo area), areas of pronounced decollement reflection, major slump masses (Nicoya slide), regions of major fracturing of the oceanic crust, or carbonate mounds (Hongo area, Mound Culebra) during previous cruises. For calibration of seismic data, survey lines were also shot in the vicinity of ODP Leg 170 drill sites. Several seismic examples from various survey sites will be shown. Closely spaced profiles, allowing the acquisition of 3D and 2.5D seismic data in the Hongo area and near Mound Culebra, respectively, reveal the complex internal structure of fluid pathways, the distribution of gas hydrates, and the tectonic framework of

  10. Current perspectives on energy and mass fluxes in volcanic arcs

    Science.gov (United States)

    Leeman, William; Davidson, Jon; Fischer, Tobias; Grunder, Anita; Reagan, Mark; Streck, Martin

    Volcanoes of the Pacific Ring of Fire and other convergent margins worldwide are familiar manifestations of nature's energy, account for about 25% of global volcanic outputs, dominate volcanic gas emissions to the atmosphere, and pose significant physical threats to a large human population. Yet the processes behind this prolific activity remain poorly understood.An international “State of the Arc” (SOTA) conference was held in August on the slopes of Mt. Hood, Oregon, to address current views on the energy and mass fluxes in volcanic arcs. This meeting brought together some 90 leading experts and students of subduction zones and their related magmatism.

  11. Burst conditions of explosive volcanic eruptions recorded on microbarographs

    Science.gov (United States)

    Morrissey, M.M.; Chouet, B.A.

    1997-01-01

    Explosive volcanic eruptions generate pressure disturbances in the atmosphere that propagate away either as acoustic or as shock waves, depending on the explosivity of the eruption. Both types of waves are recorded on microbarographs as 1- to 0.1-hertz N-shaped signals followed by a longer period coda. These waveforms can be used to estimate burst pressures end gas concentrations in explosive volcanic eruptions and provide estimates of eruption magnitudes.

  12. Innovative Seawalls and Rubble Mound Breakwater Design for Wave Energy Conversion

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Contestabile, P.; Ferrante, V.

    2012-01-01

    research has shown that they can also enhance the protective roll of coastal structures such as rubble mound breakwaters and vertical seawalls. Such WECs can in theory provide sufficient energy to partly cover the needs of small communities and although retrofitting solutions for vertical seawalls have...... been proposed no solution is yet available for rubble mound structures. A following this an overview of previous research efforts is reported here along with an ongoing experimental effort aiming on the development and optimisation of a retrofitting solution for rubble mound breakwaters. It is envisage...... that such a structure will convert wave energy to electricity and in the same time it will reduce run-up and overtopping....

  13. Distribution and physical traits of red wood ant mounds in a managed Rhodope mountains forest.

    Science.gov (United States)

    Tsikas, Angelos; Karanikola, Paraskevi; Papageorgiou, Aristotelis C

    2016-07-01

    Red wood ants (RWA) are of great ecological importance for the forest ecosystem. Forestry practices, like clear-cutting, and trampling load, due to tourism, logging, and grazing stock, can greatly affect their colonies, disturbing their microhabitat. RWA in Greek forests have not been investigated so far. We herein report on the distribution and morphological traits of Formica lugubris mounds studied in Elatia forest (Rhodope mountains, Northern Greece), an all-aged managed mixed forest where selective logging practices are performed. Nearby vegetation, slope, canopy cover, shrub density, and distance from the nearest neighboring trees were also recorded. Mound density was shown to be much higher in this Greek forest compared to RWA mounds in other European-managed forests. Furthermore, we recorded a continuous nest establishment, despite forest management disturbances and trampling load. Our study suggests that single-tree selective forestry practices are essential for creating ideal microhabitats for the RWA and, therefore, for maintaining RWA populations.

  14. Recognition and Significance of Volcanic Rocks of the Anda Depression of the Songliao Basin in Jurassic-Cretaceous

    Institute of Scientific and Technical Information of China (English)

    Fuhong Gao; Dongpo Wang; Xinrong Zhang; Guixia Ji; Jian Zhao

    2003-01-01

    A series of volcanic rocks were developed in the deep part of Anda faulting depression. The reflection of therocks are mainly stratiform and hummocky. Three kinds of volcanic facies, e.g. explosion facies, effusion facies andsub-volcanic facies,were recognized by different reflecting characteristics in the seismic profile. The volcanic rocks areformed during three episodes of volcanic activities from Shahezi Formation to Yingcheng Formation. The volcanismshave relation to the formation of Songliao Basin and regional tectonics of northeastern China. Some of the volcanic rocksare good oil and gas reservoirs.

  15. Analysis of cavern stability at the Bryan Mound SPR site.

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, Brian L.; Sobolik, Steven Ronald

    2009-04-01

    This report presents computational analyses that simulate the structural response of caverns at the Strategic Petroleum Reserve Bryan Mound site. The cavern field comprises 20 caverns. Five caverns (1, 2, 4, and 5; 3 was later plugged and abandoned) were acquired from industry and have unusual shapes and a history dating back to 1946. The other 16 caverns (101-116) were leached according to SPR standards in the mid-1980s and have tall cylindrical shapes. The history of the caverns and their shapes are simulated in a 3-D geomechanics model of the site that predicts deformations, strains, and stresses. Future leaching scenarios due to oil drawdowns using fresh water are also simulated by increasing the volume of the caverns. Cavern pressures are varied in the model to capture operational practices in the field. The results of the finite element model are interpreted to provide information on the current and future status of subsidence, well integrity, and cavern stability. The most significant result in this report is relevant to caverns 1, 2, and 5. The caverns have non-cylindrical shapes and have potential regions where the surrounding salt may be damaged during workover procedures. During a workover the normal cavern operating pressure is lowered to service a well. At this point the wellhead pressures are atmospheric. When the workover is complete, the cavern is repressurized. The resulting elastic stresses are sufficient to cause tension and large deviatoric stresses at several locations. With time, these stresses relax to a compressive state due to salt creep. However, the potential for salt damage and fracturing exists. The analyses predict tensile stresses at locations with sharp-edges in the wall geometry, or in the case of cavern 5, in the neck region between the upper and lower lobes of the cavern. The effects do not appear to be large-scale, however, so the only major impact is the potential for stress-induced salt falls in cavern 5, potentially leading to

  16. SO2 flux and the thermal power of volcanic eruptions

    Science.gov (United States)

    Henley, Richard W.; Hughes, Graham O.

    2016-09-01

    A description of the dynamics, chemistry and energetics governing a volcanic system can be greatly simplified if the expansion of magmatic gas can be assumed to be adiabatic as it rises towards the surface. The conditions under which this assumption is valid are clarified by analysis of the transfer of thermal energy into the low conductivity wallrocks traversed by fractures and vents from a gas phase expanding over a range of mass flux rates. Adiabatic behavior is predicted to be approached typically within a month after perturbations in the release of source gas have stabilized, this timescale being dependent upon only the characteristic length scale on which the host rock is fractured and the thermal diffusivity of the rock. This analysis then enables the thermal energy transport due to gas release from volcanoes to be evaluated using observations of SO2 flux with reference values for the H2O:SO2 ratio of volcanic gas mixtures discharging through high temperature fumaroles in arc and mantle-related volcanic systems. Thermal power estimates for gas discharge are 101.8 to 104.1 MWH during quiescent, continuous degassing of arc volcanoes and 103.7 to 107.3 MWH for their eruptive stages, the higher value being the Plinean Pinatubo eruption in 1991. Fewer data are available for quiescent stage mantle-related volcanoes (Kilauea 102.1 MWH) but for eruptive events power estimates range from 102.8 MWH to 105.5 MWH. These estimates of thermal power and mass of gas discharges are commensurate with power estimates based on the total mass of gas ejected during eruptions. The sustained discharge of volcanic gas during quiescent and short-lived eruptive stages can be related to the hydrodynamic structure of volcanic systems with large scale gaseous mass transfer from deep in the crust coupled with episodes of high level intrusive activity and gas release.

  17. Case Study of Volcanic Rock Reservoir--Beibao Area of Nanbao Sag

    Institute of Scientific and Technical Information of China (English)

    Guo Qijun; Wan Zhimin; Jiao Shouquan; Liu Laixiang

    1997-01-01

    @@ Preface Crude has been produced from volcanic rock reservoirs inAmerica, Libya, Indonesia and Japan, according to the available data. Oil and gas Production from volcanic rock reservoirs in Japan accounts for 30% of the total, with the recoverable reserves estimated at 48% of the total. Oil and gas traps of volcanic rock reservoir with better reservoir properties and flow potential have been discovered in Liaohe, Erlian, Jizhong, Huanghua, Jiyang, Linqing,Jiangsu and Xinjiang of China since the 1970's. However,the systematic study of volcanic rock reservoir is just in the beginning.

  18. Sedimentation patterns on a cold-water coral mound off Mauritania

    Science.gov (United States)

    Eisele, Markus; Frank, Norbert; Wienberg, Claudia; Titschack, Jürgen; Mienis, Furu; Beuck, Lydia; Tisnerat-Laborde, Nadine; Hebbeln, Dierk

    2014-01-01

    An unconformity-bound glacial sequence (135 cm thick) of a coral-bearing sediment core collected from the flank of a cold-water coral mound in the Banda Mound Province off Mauritania was analysed. In order to study the relation between coral framework growth and its filling by hemipelagic sediments, U-series dates obtained from the cold-water coral species Lophelia pertusa were compared to 14C dates of planktonic foraminifera of the surrounding matrix sediments. The coral ages, ranging from 45.1 to 32.3 ka BP, exhibit no clear depositional trend, while on the other hand the 14C dates of the matrix sediment provide ages within a much narrower time window of <3000 yrs (34.6-31.8 cal ka BP), corresponding to the latest phase of the coral growth period. In addition, high-resolution computer tomography data revealed a subdivision of the investigated sediment package into three distinct parts, defined by the portion and fragmentation of corals and associated macrofauna as well as in the density of the matrix sediments. Grain size spectra obtained on the matrix sediments show a homogeneous pattern throughout the core sediment package, with minor variations. These features are interpreted as indicators of redeposition. Based on the observed structures and the dating results, the sediments were interpreted as deposits of a mass wasting event, namely a debris flow. During this event, the sediment unit must have been entirely mixed; resulting in averaging of the foraminifera ages from the whole unit and giving randomly distributed coral ages. In this context, for the first time mass wasting is proposed to be a substantial process of mound progradation by exporting material from the mound top to the flanks. Hence, it may not only be an erosional feature but also widening the base of the mound, thus allowing further vertical mound growth.

  19. Mounding of a non-Newtonian jet impinging on a solid substrate.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Grillet, Anne Mary; Roberts, Scott A.; Baer, Thomas A. (Procter & Gamble, Cincinnati, OH); Rao, Rekha Ranjana

    2010-06-01

    When a fluid jet impinges on a solid substrate, a variety of behaviors may occur around the impact region. One example is mounding, where the fluid enters the impact region faster than it can flow away, forming a mound of fluid above the main surface. For some operating conditions, this mound can destabilize and buckle, entraining air in the mound. Other behaviors include submerging flow, where the jet impinges into an otherwise steady pool of liquid, entraining a thin air layer as it enters the pool. This impact region is one of very high shear rates and as such, complex fluids behave very differently than do Newtonian fluids. In this work, we attempt to characterize this range of behavior for Newtonian and non-Newtonian fluids using dimensionless parameters. We model the fluid as a modified Bingham-Carreau-Yasuda fluid, which exhibits the full range of pseudoplastic flow properties throughout the impact region. Additionally, we study viscoelastic effects through the use of the Giesekus model. Both 2-D and 3-D numerical simulations are performed using a variety of finite element method techniques for tracking the jet interface, including Arbitrary Lagrangian Eulerian (ALE), diffuse level sets, and a conformal decomposition finite element method (CDFEM). The presence of shear-thinning characteristics drastically reduces unstable mounding behavior, yet can lead to air entrainment through the submerging flow regime. We construct an operating map to understand for what flow parameters mounding and submerging flows will occur, and how the fluid rheology affects these behaviors. This study has many implications in high-speed industrial bottle filling applications.

  20. Can mima-like mounds be Vertisol relics (Far North Region of Cameroon, Chad Basin)?

    Science.gov (United States)

    Diaz, Nathalie; Dietrich, Fabienne; Cailleau, Guillaume; Sebag, David; Ngounou Ngatcha, Benjamin; Verrecchia, Eric P.

    2016-05-01

    Non-anthropogenic earth mounds, defined as mima-like mounds in this study, have recently been observed in non-carbonate watersheds along the Sudano-Sahelian belt in the Chad Basin. In the Diamare piedmont (northern Cameroon) they are particularly well developed within stream networks. In less eroded areas, they occur as whaleback, flattened morphologies, or even as buried features. All these shapes are composed of clay-rich sediment associated with high proportions of secondary carbonate nodules and Fesbnd Mn micro-nodules. Their soil structure is prismatic to massive and vertical cracks are observed locally. Grain-size distributions emphasize the clay-rich nature of the sediment, with average clay contents of 32% ± 12.8% (n = 186), which is significantly higher than the clay content in the adjacent sediments in the landscape (mean = 10% ± 4%, n = 21). Moreover, high proportions of smectite characterize the soil, with average contents of 34 ± 7% (n = 25). At the micro-scale, the groundmass has a cross-striated b-fabric, with embedded smooth subangular quartz and feldspar grains of the silt-size fraction. All the characteristics point to altered vertic properties in the clay-rich sediment composing the mima-like mounds. Mima-like mounds are thus interpreted as degraded Vertisols. Compared to present-day Vertisols occurring in the piedmont, mima-like mounds are located upstream. It is thus proposed that the Vertisol areas were more extensive during a former and wetter period than the present-day. Subsequent changing climatic conditions increased erosion, revealing the gilgai micro-relief by preferential erosion in micro-lows rather than in micro-highs. Mima-like mounds of the Chad Basin might thus result from pedogenesis combined with later erosion. These local processes can be inherited from regional climatic variations during the Late Pleistocene-Holocene and likely be related to the African Humid Period.

  1. Volcanic lake systematics II. Chemical constraints

    Science.gov (United States)

    Varekamp, J.C.; Pasternack, G.B.; Rowe, G.L.

    2000-01-01

    A database of 373 lake water analyses from the published literature was compiled and used to explore the geochemical systematics of volcanic lakes. Binary correlations and principal component analysis indicate strong internal coherence among most chemical parameters. Compositional variations are influenced by the flux of magmatic volatiles and/or deep hydrothermal fluids. The chemistry of the fluid entering a lake may be dominated by a high-temperature volcanic gas component or by a lower-temperature fluid that has interacted extensively with volcanic rocks. Precipitation of minerals like gypsum and silica can strongly affect the concentrations of Ca and Si in some lakes. A much less concentrated geothermal input fluid provides the mineralized components of some more dilute lakes. Temporal variations in dilution and evaporation rates ultimately control absolute concentrations of dissolved constituents, but not conservative element ratios. Most volcanic lake waters, and presumably their deep hydrothermal fluid inputs, classify as immature acid fluids that have not equilibrated with common secondary silicates such as clays or zeolites. Many such fluids may have equilibrated with secondary minerals earlier in their history but were re-acidified by mixing with fresh volcanic fluids. We use the concept of 'degree of neutralization' as a new parameter to characterize these acid fluids. This leads to a classification of gas-dominated versus rock-dominated lake waters. A further classification is based on a cluster analysis and a hydrothermal speedometer concept which uses the degree of silica equilibration of a fluid during cooling and dilution to evaluate the rate of fluid equilibration in volcano-hydrothermal systems.

  2. 75 FR 27783 - Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Site in...

    Science.gov (United States)

    2010-05-18

    ... revision as warranted by the evaluation, is as follows: Facility: Mound site. Location: Miamisburg, Ohio... Doc No: 2010-11875] DEPARTMENT OF HEALTH AND HUMAN SERVICES Decision To Evaluate a Petition To... decision to evaluate a petition to designate a class of employees from the Mound site in Miamisburg, Ohio...

  3. 77 FR 59615 - Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Plant in...

    Science.gov (United States)

    2012-09-28

    ... warranted by the evaluation, is as follows: Facility: Mound Plant. Location: Miamisburg, Ohio. Job Titles... HUMAN SERVICES Decision To Evaluate a Petition To Designate a Class of Employees From the Mound Plant in... Services. ACTION: Notice. SUMMARY: NIOSH gives notice as required by 42 CFR 83.12(e) of a decision to...

  4. Cold-water coral mounds on the Pen Duick Escarpment, Gulf of Cadiz: The MiCROSYSTEMS project approach

    NARCIS (Netherlands)

    Van Rooij, D.; Blamart, D.; De Mol, L.; Mienis, F.; Pirlet, H.; Wehrmann, L. M.; Barbieri, R.; Maignien, L.; Templer, S. P.; de Haas, H.; Hebbeln, D.; Frank, N.; Larmagnat, S.; Stadnitskaia, A.; Stivaletta, N.; van Weering, T.; Zhang, Y.; Hamoumi, N.; Cnudde, V.; Duyck, P.; Henriet, J.-P.; The MiCROSYSTEMS MD 169 Shipboard Party

    2011-01-01

    Here we present a case study of three cold-water coral mounds in a juvenile growth stage on top of the Pen Duick Escarpment in the Gulf of Cadiz; Alpha, Beta and Gamma mounds. Although cold-water corals are a common feature on the adjacent cliffs, mud volcanoes and open slope, no actual living cold-

  5. Subsurface microbiology and biogeochemistry of a deep, cold-water carbonate mound from the Porcupine Seabight (IODP Expedition 307).

    Science.gov (United States)

    Webster, Gordon; Blazejak, Anna; Cragg, Barry A; Schippers, Axel; Sass, Henrik; Rinna, Joachim; Tang, Xiaohong; Mathes, Falko; Ferdelman, Timothy G; Fry, John C; Weightman, Andrew J; Parkes, R John

    2009-01-01

    The Porcupine Seabight Challenger Mound is the first carbonate mound to be drilled (approximately 270 m) and analyzed in detail microbiologically and biogeochemically. Two mound sites and a non-mound Reference site were analyzed with a range of molecular techniques [catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), quantitative PCR (16S rRNA and functional genes, dsrA and mcrA), and 16S rRNA gene PCR-DGGE] to assess prokaryotic diversity, and this was compared with the distribution of total and culturable cell counts, radiotracer activity measurements and geochemistry. There was a significant and active prokaryotic community both within and beneath the carbonate mound. Although total cell numbers at certain depths were lower than the global average for other subseafloor sediments and prokaryotic activities were relatively low (iron and sulfate reduction, acetate oxidation, methanogenesis) they were significantly enhanced compared with the Reference site. In addition, there was some stimulation of prokaryotic activity in the deepest sediments (Miocene, > 10 Ma) including potential for anaerobic oxidation of methane activity below the mound base. Both Bacteria and Archaea were present, with neither dominant, and these were related to sequences commonly found in other subseafloor sediments. With an estimate of some 1600 mounds in the Porcupine Basin alone, carbonate mounds may represent a significant prokaryotic subseafloor habitat.

  6. Functional traits of trees on and off termite mounds : Understanding the origin of biotically-driven heterogeneity in savannas

    NARCIS (Netherlands)

    van der Plas, F.; Howison, R.; Reinders, J.; Fokkema, W.; Olff, H.

    2013-01-01

    Questions In African savannas, Macrotermes termites contribute to small-scale heterogeneity by constructing large mounds. Operating as islands of high nutrient and water availability and low fire frequency, these mounds support distinct, diverse communities of trees that have been shown to be highly

  7. Spatial patternd and morphology of termite (macrotermes falciger) mounds in the upper Katanga, D.R. Congo

    NARCIS (Netherlands)

    Mujinya, B.B.; Adam, M.Y.O.; Mees, F.; Bogaert, J.; Vranken, I.; Erens, H.; Baert, G.; Ngongo, M.; Ranst, van E.

    2014-01-01

    This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were assessed using high-resolution satellite images for 24 plots of variable size (3 to 27 ha). Soil mo

  8. Relict nebkhas (pimple mounds) record prolonged late Holocene drought in the forested region of south-central United States

    Science.gov (United States)

    Seifert, Christopher L.; Cox, Randel Tom; Forman, Steven L.; Foti, Tom L.; Wasklewicz, Thad A.; McColgan, Andrew T.

    2009-05-01

    The origin and significance of pimple mounds (low, elliptical to circular dune-like features found across much of the south-central United States) have been debated for nearly two centuries. We cored pimple mounds at four sites spanning the Ozark Plateau, Arkansas River Valley, and Gulf of Mexico Coastal Plain and found that these mounds have a regionally consistent textural asymmetry such that there is a significant excess of coarse-grained sediment within their northwest flanks. We interpret this asymmetry as evidence of an eolian depositional origin of these mounds and conclude they are relict nebkhas (coppice dunes) deposited during protracted middle to late Holocene droughts. These four mounds yield optically stimulated luminescence ages between 2400 and 700 yr that correlate with well-documented periods of eolian activity and droughts on the southern Great Plains, including the Medieval Climate Anomaly. We conclude vegetation loss during extended droughts led to local eolian deflation and pimple mound deposition. These mounds reflect landscape response to multi-decadal droughts for the south-central U.S. The spatial extent of pimple mounds across this region further underscores the severity and duration of late Holocene droughts, which were significantly greater than historic droughts.

  9. Cold-water coral mounds on the Pen Duick Escarpment, Gulf of Cadiz: The MiCROSYSTEMS project approach

    NARCIS (Netherlands)

    Van Rooij, D.; Blamart, D.; De Mol, L.; Mienis, F.; Pirlet, H.; Wehrmann, L. M.; Barbieri, R.; Maignien, L.; Templer, S. P.; de Haas, H.; Hebbeln, D.; Frank, N.; Larmagnat, S.; Stadnitskaia, A.; Stivaletta, N.; van Weering, T.; Zhang, Y.; Hamoumi, N.; Cnudde, V.; Duyck, P.; Henriet, J.-P.; The MiCROSYSTEMS MD 169 Shipboard Party

    2011-01-01

    Here we present a case study of three cold-water coral mounds in a juvenile growth stage on top of the Pen Duick Escarpment in the Gulf of Cadiz; Alpha, Beta and Gamma mounds. Although cold-water corals are a common feature on the adjacent cliffs, mud volcanoes and open slope, no actual living

  10. On the Origin of the Dragon Image on the Plate from Shilovka Burial Mound

    OpenAIRE

    Liphanov Nicolay А.

    2017-01-01

    The author of the article analyzes an unique image of two opposed dragons engraved on a bone plate discovered in 1992 at barrow No.1 of Shilovka burial mound located on the right bank of the Volga river in Ulyanovsk Oblast (the excavations were conducted by R.S. Bagautdinov). The burial mound is related to the cattle breeding population of late 7th century. The article considers different hypotheses concerning the origin of these dragon images in the artistic traditions of various regions: Ch...

  11. Development of a Partial Coefficient System for the Design of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.

    Subgroup F is the last of the subgroups formed under the PIANC II Working Group 12 on Rubble Mound Structures. The terms of reference of subgroup F are to propose safety guidelines for rubble mound breakwaters including evaluation of the safety levels inherent in conventionally designed existing...... structures. The work of the former subgroups A, B, C. D and E provides the basis for the handling of a number of the central problems related to the development of safety guidelines. The Working Group 12 (WG12) decided prior to the start of subgroup F that the safety guidelines should be based on the partial...

  12. Timing of mounding for bambara groundnut affects crop development and yield in a rainfed tropical environment

    DEFF Research Database (Denmark)

    Ouedrago, Mahama; M'bi, Bertin Zagre; Liu, Fulai;

    2013-01-01

    to the crown of bambara groundnut plants and has been shown to improve seed yield of the crop. However, little information exists if and how the timing of mounding affects the productivity of the crop. To address this, two experiments during two consecutive years in rainfed fields in the Sudan–Sahel agro-ecological...... zone of Burkina Faso were conducted. Yield data confirm the findings from a drier part of Burkina Faso; i.e., mounding of bambara groundnut should not be carried out around the time of flowering. In a semi-arid area, such as Sudan–Sahel agro-ecological zone and with germplasm maturing within 90 days...

  13. Overview of the earth mounded concrete bunker prototype license application project: Objectives and approach

    Energy Technology Data Exchange (ETDEWEB)

    Conner, J.E. [EG and G Idaho, Inc., Idaho Falls, ID (United States). Idaho National Engineering Lab.

    1989-11-01

    This paper presents an overview of the objectives and approach taken in developing the Earth-mounded Concrete Bunker Prototype License Application Project. The Prototype License Application Project was initiated by the Department of Energy`s National Low-Level Waste Management Program in early 1987 and completed in November 1988. As part of this project a prototype safety analysis report was developed. The safety analysis report evaluates the licensibility of an earth-mounded concrete bunker for a low-level radioactive waste (LLW) disposal facility located on a hypothetical site in the northeastern United States. The project required approximately five person-years and twenty months to develop.

  14. Overview of the earth mounded concrete bunker prototype license application project: Objectives and approach

    Energy Technology Data Exchange (ETDEWEB)

    Conner, J.E. [EG and G Idaho, Inc., Idaho Falls, ID (United States). Idaho National Engineering Lab.

    1989-11-01

    This paper presents an overview of the objectives and approach taken in developing the Earth-mounded Concrete Bunker Prototype License Application Project. The Prototype License Application Project was initiated by the Department of Energy`s National Low-Level Waste Management Program in early 1987 and completed in November 1988. As part of this project a prototype safety analysis report was developed. The safety analysis report evaluates the licensibility of an earth-mounded concrete bunker for a low-level radioactive waste (LLW) disposal facility located on a hypothetical site in the northeastern United States. The project required approximately five person-years and twenty months to develop.

  15. Archaeomagnetic study of ancient slag mounds in Cyprus: continuous paleointensity curves in high resolution

    Science.gov (United States)

    Shaar, R.; Tauxe, L.; Ben-Yosef, E.; Levy, T. E.; Kassianidou, V.; Lorentzen, B. E.

    2012-12-01

    One of the main challenges in paleointensity research is obtaining continuous high-resolution records that describe the behavior of the geomagnetic field on short time scales. One difficulty in obtaining such records is the problem of precise dating of suitable samples. Another fundamental difficulty is the assessment of the uncertainty involved in the interpretation of paleointensity experiments. Here we present an archaeomagnetic study of ancient slag mounds, which is designed to minimize these difficulties. We study two archaeological slag mounds in the Troodos foothills of Cyprus; one from the massive Roman mines at Skouriotissa, and another pre Roman near Mitsero Kokkinoyia. The mounds consist of industrial layers of copper slag intermixed with charcoal, which were deposited during times of intense copper smelting activity. The slag mound at Skouriotissa represents one of the largest copper production sites in the ancient world, including a 25 m high section and more than 40 archaeological layers. The mound at Mitsero is ca. 10 m high and contains about 32 layers. Hundreds of slag samples and associated charcoals from both mounds were collected, from which more than 600 slag specimens from more than 150 individual samples were analyzed for paleointensity. In addition,19 charcoals were radiocarbon dated. To minimize the uncertainty in the radiocarbon dating we applied a Bayesian model for each mound, which takes into account the relative stratigraphy of the layers. To reduce the uncertainty involved in the subjective interpretation of the paleointensity experiments (conventionally done by manually selecting temperature bounds in the Arai plot of each specimen) we designed new optimization software. The optimization software uses the assumption that paleointensity estimates from samples that were collected from the same level, should be similar. The optimization algorithm finds the selecting criteria that yields minimum scatter within each level, assigns

  16. HYFLUX: Satellite Exploration of Natural Hydrocarbon Seeps and Discovery of a Methane Hydrate Mound at GC600

    Science.gov (United States)

    Garcia-Pineda, O. G.; MacDonald, I. R.; Shedd, W.; Zimmer, B.

    2009-12-01

    Analysis of natural hydrocarbon seeps is important to improve our understanding of methane flux from deeper sediments to the water column. In order to quantify natural hydrocarbon seep formations in the Northern Gulf of Mexico, a set of 686 Synthetic Aperture Radar (SAR) images was analyzed using the Texture Classifying Neural Network Algorithm (TCNNA), which processes SAR data to delineate oil slicks. This analysis resulted in a characterization of 396 natural seep sites distributed in the northern GOM. Within these sites, a maximum of 1248 individual vents where identified. Oil reaching the sea-surface is deflected from its source during transit through the water column. This presentation describes a method for estimating locations of active oil vents based on repeated slick detection in SAR. One of the most active seep formations was detected in MMS lease block GC600. A total of 82 SAR scenes (collected by RADARSAT-1 from 1995 to 2007) was processed covering this region. Using TCNNA the area covered by each slick was computed and Oil Slicks Origins (OSO) were selected as single points within detected oil slicks. At this site, oil slick signatures had lengths up to 74 km and up to 27 km^2 of area. Using SAR and TCNNA, four active vents were identified in this seep formation. The geostatistical mean centroid among all detections indicated a location along a ridge-line at ~1200m. Sea truth observations with an ROV, confirmed that the estimated location of vents had a maximum offset of ~30 m from their actual locations on the seafloor. At the largest vent, a 3-m high, 12-m long mound of oil-saturated gas hydrate was observed. The outcrop contained thousands of ice worms and numerous semi-rigid chimneys from where oily bubbles were escaping in a continuous stream. Three additional vents were found along the ridge; these had lower apparent flow, but were also plugged with gas hydrate mounds. These results support use of SAR data for precise delineation of active seep

  17. Precambrian Lunar Volcanic Protolife

    Directory of Open Access Journals (Sweden)

    Jack Green

    2009-06-01

    Full Text Available Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.

  18. Internal structure and depositional environment of Late Carboniferous mounds from the San Emiliano Formation, Cármenes Syncline, Cantabrian Mountains, Northern Spain

    OpenAIRE

    2005-01-01

    Well-exposed mounds are common in limestone of the Late Carboniferous San Emiliano Formation, Cantabrian Mountains (Northern Spain). They occur as obvious primary topographic features. Careful study of the mound intervals and surrounding strata revealed the internal structures of mounds and the factors controlling their growth. The substrate (2–3 m) of the mounds consists of greyish to reddish, bedded oolitic and oncolithic packstone and grainstone. Crinoids, fragments of the alga Epimastopor...

  19. Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.

    Directory of Open Access Journals (Sweden)

    Stephen J Levas

    Full Text Available Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13C of the skeletal, δ(13C, and δ(15N of the animal host and endosymbiont fractions. Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic

  20. Lung problems and volcanic smog

    Science.gov (United States)

    ... releases gases into the atmosphere. Volcanic smog can irritate the lungs and make existing lung problems worse. ... deep into the lungs. Breathing in volcanic smog irritates the lungs and mucus membranes. It can affect ...

  1. Linking benthic dynamics and cold-water coral occurrences: A high-resolution model study at three carbonate mound provinces in the NE Atlantic

    DEFF Research Database (Denmark)

    Mohn, Christian; Rengstorf, Anna; Grehan, Anthony;

    We used the 3-D ocean circulation model with grid refinement ROMS-AGRIF to describe the hydrodynamic conditions at three cold-water coral provinces in the NE Atlantic (Logachev Mounds, Arc Mounds and Belgica Mounds). Modelled fields of currents, temperature and salinity were analysed for observed...

  2. Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography

    NARCIS (Netherlands)

    van Bleijswijk, J.D.L.; Whalen, C.; Duineveld, G.C.A.; Lavaleye, M.S.S.; Witte, H.J.; Mienis, F

    2015-01-01

    This study characterizes the microbial community composition over Haas Mound, one of the most prominent cold-water coral mounds of the Logachev Mound province (Rockall Bank, NE Atlantic). We outline patterns of distribution vertically – from the seafloor to the water column – and laterally – across

  3. Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography

    NARCIS (Netherlands)

    van Bleijswijk, J.D.L.; Whalen, C.; Duineveld, G.C.A.; Lavaleye, M.S.S.; Witte, H.J.; Mienis, F

    2015-01-01

    This study characterizes the microbial community composition over Haas Mound, one of the most prominent cold-water coral mounds of the Logachev Mound province (Rockall Bank, NE Atlantic). We outline patterns of distribution vertically – from the seafloor to the water column – and laterally – across

  4. Is volcanic phenomena of fractal nature?

    Science.gov (United States)

    Quevedo, R.; Lopez, D. A. L.; Alparone, S.; Hernandez Perez, P. A.; Sagiya, T.; Barrancos, J.; Rodriguez-Santana, A. A.; Ramos, A.; Calvari, S.; Perez, N. M.

    2016-12-01

    A particular resonance waveform pattern has been detected beneath different physical volcano manifestations from recent 2011-2012 period of volcanic unrest at El Hierro Island, Canary Islands, and also from other worldwide volcanoes with different volcanic typology. This mentioned pattern appears to be a fractal time dependent waveform repeated in different time scales (periods of time). This time dependent feature suggests this resonance as a new approach to volcano phenomena for predicting such interesting matters as earthquakes, gas emission, deformation etc. as this fractal signal has been discovered hidden in a wide typical volcanic parameters measurements. It is known that the resonance phenomenon occurring in nature usually denote a structure, symmetry or a subjacent law (Fermi et al., 1952; and later -about enhanced cross-sections symmetry in protons collisions), which, in this particular case, may be indicative of some physical interactions showing a sequence not completely chaotic but cyclic provided with symmetries. The resonance and fractal model mentioned allowed the authors to make predictions in cycles from a few weeks to months. In this work an equation for this waveform has been described and also correlations with volcanic parameters and fractal behavior demonstration have been performed, including also some suggestive possible explanations of this signal origin.

  5. Synthetically and quantitatively assessing gas-sealing ability of volcanic cap rocks in the Xujiaweizi Sag of the Songliao Basin%松辽盆地徐家围子断陷火山岩盖层封气能力综合定量评价

    Institute of Scientific and Technical Information of China (English)

    史集建; 吕延防; 付广; 李丽丽

    2011-01-01

    对松辽盆地徐家围子断陷14个火山岩盖层气藏解剖研究表明,徐家围子断陷白垩系营城组一段顶部火山岩盖层具有高声波时差和井径扩容的特征,岩性主要为凝灰岩、火山角砾岩等,厚度为0~80m,是一套良好的局部盖层.在分析火山岩盖层封气能力的影响因素,即火山岩厚度、排替压力、断层垂向封闭性、天然气黏度和气藏压力基础上,建立了火山岩封气能力综合评价方法,并得到天然气储量丰度与其火山岩盖层封气能力综合评价参数a具有正相关关系.结合天然气储量丰度的划分标准,得到徐家围子断陷形成高储量丰度气藏所需要的a值大于或等于0.005m·Pa·s,形成中等储量丰度气藏所需要的a值为00005~0.002m·Pa·s,形成低储量车度气藏所需要的a值为0.002~0.0003m·Pa·s,形成特低储量丰度气藏所需要的a值小于0.0003m·Pa·s.由此得到火山岩盖层封气能力分布特征:封闭高储量丰度气藏的火山岩盖层主要分布在徐家围子断陷东北部地区;封闭中等储量丰度气藏的火山岩盖层全区基本均有分布;封闭低储量丰度气藏的火山岩盖层主要分布在徐家围子断陷中部和南部地区,西北部也有局部分布;封闭特低储量丰度气藏的火山岩盖层在全区零星分布,主要处于火山岩盖层的尖灭线附近.徐家围子断陷天然气的富集在一定程度上受到火山岩盖层封气能力的控制.%The present paper studied 14 gas reservoirs in the Xujiaweizi rift Sag, Songliao Basin thoroughly and the result showed that volcanic rocks in the top of the first member of Yingcheng Formation, composed mainly of tuff and volcanic breccia with a thickness between 0 and 80 cm, were characterized by high interval transit time and enlarged borehole diameter, and locally formed a suite of good cap rocks.Consequently, a method was established for synthetically assessing gas-sealing ability of these

  6. Volcanic jet noise: infrasonic source processes and atmospheric propagation

    Science.gov (United States)

    Matoza, R. S.; Fee, D.; Ogden, D. E.

    2011-12-01

    Volcanic eruption columns are complex flows consisting of (possibly supersonic) injections of ash-gas mixtures into the atmosphere. A volcanic eruption column can be modeled as a lower momentum-driven jet (the gas-thrust region), which transitions with altitude into a thermally buoyant plume. Matoza et al. [2009] proposed that broadband infrasonic signals recorded during this type of volcanic activity represent a low-frequency form of jet noise. Jet noise is produced at higher acoustic frequencies by smaller-scale man-made jet flows (e.g., turbulent jet flow from jet engines and rockets). Jet noise generation processes could operate at larger spatial scales and produce infrasonic frequencies in the lower gas-thrust portion of the eruption column. Jet-noise-like infrasonic signals have been observed at ranges of tens to thousands of kilometers from sustained volcanic explosions at Mount St. Helens, WA; Tungurahua, Ecuador; Redoubt, AK; and Sarychev Peak, Kuril Islands. Over such distances, the atmosphere cannot be considered homogeneous. Long-range infrasound propagation takes place primarily in waveguides formed by vertical gradients in temperature and horizontal winds, and exhibits strong spatiotemporal variability. The timing and location of volcanic explosions can be estimated from remote infrasonic data and could be used with ash cloud dispersion forecasts for hazard mitigation. Source studies of infrasonic volcanic jet noise, coupled with infrasound propagation modeling, hold promise for being able to constrain more detailed eruption jet parameters with remote, ground-based geophysical data. Here we present recent work on the generation and propagation of volcanic jet noise. Matoza, R. S., D. Fee, M. A. Garcés, J. M. Seiner, P. A. Ramón, and M. A. H. Hedlin (2009), Infrasonic jet noise from volcanic eruptions, Geophys. Res. Lett., 36, L08303, doi:10.1029/2008GL036486.

  7. The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

    Science.gov (United States)

    Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.

    2001-12-01

    The awesome power and intricate inner workings of volcanoes have made them a popular subject with scientists and the general public alike. About 1500 known volcanoes have been active on Earth during the Holocene, approximately 50 of which erupt per year. With so much activity occurring around the world, often in remote locations, it can be difficult to find up-to-date information about current volcanism from a reliable source. To satisfy the desire for timely volcano-related information the Smithsonian Institution and US Geological Survey combined their strengths to create the Weekly Volcanic Activity Report. The Smithsonian's Global Volcanism Program (GVP) has developed a network of correspondents while reporting worldwide volcanism for over 30 years in their monthly Bulletin of the Global Volcanism Network. The US Geological Survey's Volcano Hazards Program studies and monitors volcanoes in the United States and responds (upon invitation) to selected volcanic crises in other countries. The Weekly Volcanic Activity Report is one of the most popular sites on both organization's websites. The core of the Weekly Volcanic Activity Report is the brief summaries of current volcanic activity around the world. In addition to discussing various types of volcanism, the summaries also describe precursory activity (e.g. volcanic seismicity, deformation, and gas emissions), secondary activity (e.g. debris flows, mass wasting, and rockfalls), volcanic ash hazards to aviation, and preventative measures. The summaries are supplemented by links to definitions of technical terms found in the USGS photoglossary of volcano terms, links to information sources, and background information about reported volcanoes. The site also includes maps that highlight the location of reported volcanoes, an archive of weekly reports sorted by volcano and date, and links to commonly used acronyms. Since the Weekly Volcanic Activity Report's inception in November 2000, activity has been reported at

  8. Modeling volcanic ash dispersal

    CERN Document Server

    CERN. Geneva

    2010-01-01

    The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

  9. The early diagenetic and PETROphysical behaviour of recent cold-water CARbonate mounds in Deep Environments (PETROCARDE)

    Science.gov (United States)

    Foubert, Anneleen; Pirlet, Hans; Thierens, Mieke; de Mol, Ben; Henriet, Jean-Pierre; Swennen, Rudy

    2010-05-01

    Sub-recent cold-water carbonate mounds localized in deeper slope settings on the Atlantic continental margins cannot be any longer neglected in the study of carbonate systems. They clearly play a major role in the dynamics of mixed siliciclastic-carbonate and/or carbonate-dominated continental slopes. Carbonate accumulation rates of cold-water carbonate mounds are about 4 to 12 % of the carbonate accumulation rates of tropical shallow-water reefs but exceed the carbonate accumulation rates of their slope settings by a factor of 4 to 12 (Titschack et al., 2009). These findings emphasize the importance of these carbonate factories as carbonate niches on the continental margins. The primary environmental architecture of such carbonate bodies is well-characterized. However, despite proven evidences of early diagenesis overprinting the primary environmental record (e.g. aragonite dissolution) (Foubert & Henriet, 2009), the extent of early diagenetic and biogeochemical processes shaping the petrophysical nature of mounds is until now not yet fully understood. Understanding (1) the functioning of a carbonate mound as biogeochemical reactor triggering early diagenetic processes and (2) the impact of early diagenesis on the petrophysical behaviour of a carbonate mound in space and through time are necessary (vital) for the reliable prediction of potential late diagenetic processes. Approaching the fossil carbonate mound record, through a profound study of recent carbonate bodies is innovative and will help to better understand processes observed in the fossil mound world (such as cementation, brecciation, fracturing, etc…). In this study, the 155-m high Challenger mound (Porcupine Seabight, SW of Ireland), drilled during IODP Expedition 307 aboard the R/V Joides Resolution (Foubert & Henriet, 2009), and mounds from the Gulf of Cadiz (Moroccan margin) will be discussed in terms of early diagenetic processes and petrophysical behaviour. Early differential diagenesis

  10. 松辽盆地火山岩高含CO2气藏包裹体特征及成藏期次%Inclusions Characteristics and Pool-Forming Periods of High CO2 Volcanic Gas Reservoirs in Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    魏立春; 鲁雪松; 宋岩; 柳少波; 洪峰

    2012-01-01

    On the basis of detailed observation of petrography, and this study defined the types, periods and compositions of fluid inclusions in the volcanic rocks of the Yingcheng Formation in Songliao basin, using the characteristics of fluid inclusion, homogenization temperature, gas composition and carbon isotopes. In addition, the pool-forming periods of volcanic gas reservoirs with a high content of CO2 were analyzed. Integrated geological and geochemical evidence shows that hydrocarbon accumulation features in the volcanic CO2 -bearing reservoir in Songliao basin contain two accumulation periods characterized by-successive recharging process, I. E. , sedimentary period of Quantou-Qingshankou formations and the middle-late stage of Nenjiang Formation deposition. CO- was recharged in the Himalaya period, later than hydrocarbon gas.%在详细岩相学观察的基础上,充分利用包裹体的岩相学特征、均一温度特征、气体组分特征以及碳同位素特征等,确定了松辽盆地营城组火山岩中包裹体的类型、期次和成分特征,并对火山岩高含CO2气藏的成藏期次进行了分析.综合各种地质地化证据,确定松辽盆地火山岩高含CO2气藏中烃类气成藏特征是连续充注基础上的两期成藏,即泉头组—青山口组沉积时期和嫩江组沉积中后期;CO2充注发生在喜山期,CO2的充注晚于烃类气的充注.

  11. Regional Mapping and Resource Assessment of Shallow Gas Hydrates of Japan Sea - METI Launched 3 Years Project in 2013.

    Science.gov (United States)

    Matsumoto, R.

    2014-12-01

    Agency of Natural Resources and Energy of METI launched a 3 years shallow gas hydrate exploration project in 2013 to make a precise resource assessment of shallow gas hydrates in the eastern margin of Japan Sea and around Hokkaido. Shallow gas hydrates of Japan Sea occur in fine-grained muddy sediments of shallow subsurface of mounds and gas chimneys in the form of massive nodular to platy accumulation. Gas hydrate bearing mounds are often associated with active methane seeps, bacterial mats and carbonate concretions and pavements. Gases of gas hydrates are derived either from deep thermogenic, shallow microbial or from the mixed gases, contrasting with totally microbial deep-seated stratigraphically controlled hydrates. Shallow gas hydrates in Japan Sea have not been considered as energy resource due to its limited distribution in narrow Joetsu basin. However recently academic research surveys have demonstrated regional distribution of gas chimney and hydrate mound in a number of sedimentary basins along the eastern margin of Japan Sea. Regional mapping of gas chimney and hydrate mound by means of MBES and SBP surveys have confirmed that more than 200 gas chimneys exist in 100 km x 100 km area. ROV dives have identified dense accumulation of hydrates on the wall of half collapsed hydrate mound down to 30 mbsf. Sequential LWD and shallow coring campaign in the Summer of 2014, R/V Hakurei, which is equipped with Fugro Seacore R140 drilling rig, drilled through hydrate mounds and gas chimneys down to the BGHS (base of gas hydrate stability) level and successfully recovered massive gas hydrates bearing sediments from several horizons.

  12. Wave Loads on Rubble Mound Breakwater Crown Walls in Long Waves

    DEFF Research Database (Denmark)

    Røge, Mads Sønderstrup; Færch Christensen, Nicole; Thomsen, Jonas Bjerg;

    2014-01-01

    This paper evaluates the formulae by Nørgaard et al. (2013) for predicting wave loads on rubble mound breakwater crown walls on new model tests. The formulae are tested outside their validation area by means of waves with a low wave steepness and low run-up height compared to the armour freeboard...

  13. Paleo-redox fronts and their formation in carbonate mound sediments from the Rockall Trough

    NARCIS (Netherlands)

    van der Land, C.; Mienis, F.; de Haas, H.; de Stigter, H.C.; Swennen, R.; Reijmer, J.J.G.; van Weering, T.C.E.

    2011-01-01

    Piston cores from the summits of coral topped carbonate mounds at the south west Rockall Trough margin reveal that the sediments have undergone significant post-depositional modifications affecting the original geochemical signature and mineralogical composition of the sediments. This diagenetic imp

  14. Mesopotamian ceramics from the burial mounds of Bahrain, c.2250–1750 BC

    DEFF Research Database (Denmark)

    Laursen, Steffen

    2011-01-01

    Among the ceramic vessels recovered from the burial mounds of Bahrain, a small percentage represents Mesopotamian imports or local emulations of such. In this paper two overall horizons are distinguished in these Mesopotamian ceramics. These are significant because both coincide with major stages...

  15. Construction, Maintenance and Repair as Elements in Rubble Mound Breakwater Design

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Rietveld, C.F.W.

    Very often rubble mound breakwater designs seem to be a result only of stability considerations corresponding to design wave conditions. Designers tend to put too little emphasis on practical problems related to construction, maintenance and repair. As is discussed in the paper due consideration ...

  16. Experimental Study and Numerical Modeling of Wave Induced Pore Pressure Attenuation Inside a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Troch, Peter; Rouck, Julien De; Burcharth, Hans Falk

    2003-01-01

    The main objective of this paper is to study the attenuation of the wave induced pore pressures inside the core of a rubble mound breakwater. The knowledge of the distribution and the attenuation of the pore pressures is important for the design of a stable and safe breakwater. The pore pressure...

  17. Single Wave Overtopping Volumes and their Travel Distance for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.; Gironella, F. X.

    2009-01-01

    In the present paper small and large scale overtopping data for rubble mound structures have been analysed with respect to single wave overtopping volumes and their travel distance. The analysis has led to formulae for estimation of maximum single wave overtopping volumes and their travel distance...

  18. On the Choice of Structure and Layout of Rubble Mound Breakwater Heads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2006-01-01

     The paper discusses the various functional, environmental and structural conditions to consider related to the choice of breakwater head type. Results from hydraulic model tests of rubble mound and caisson head solutions for the new deep water port at Punto Langosteira, La Coruña, Spain, are pre...

  19. Controls on Gas Hydrate Formation and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  20. Quantifying the morphometric variability of monogenetic cones in volcanic fields: the Virunga Volcanic Province, East African Rift

    Science.gov (United States)

    Poppe, Sam; Grosse, Pablo; Barette, Florian; Smets, Benoît; Albino, Fabien; Kervyn, François; Kervyn, Matthieu

    2016-04-01

    Volcanic cone fields are generally made up of tens to hundreds of monogenetic cones, sometimes related to larger polygenetic edifices, which can exhibit a wide range of morphologies and degrees of preservation. The Virunga Volcanic Province (VVP) developed itself in a transfer zone which separates two rift segments (i.e. Edward and Kivu rift) within the western branch of the East-African Rift. As the result of volcanic activity related to this tectonic regime of continental extension, the VVP hosts eight large polygenetic volcanoes, surrounded by over 500 monogenetic cones and eruptive fissures, scattered over the vast VVP lava flow fields. Some cones lack any obvious geo-structural link to a specific Virunga volcano. Using recent high-resolution satellite images (SPOT, Pléiades) and a newly created 5-m-resolution digital elevation model (TanDEM-X), we have mapped and classified all monogenetic cones and eruptive fissures of the VVP. We analysed the orientation of all mapped eruptive fissures and, using the MORVOLC program, we calculated a set of morphometric parameters to highlight systematic spatial variations in size or morphometric ratios of the cones. Based upon morphological indicators, we classified the satellite cones into 4 categories: 1. Simple cones with one closed-rim crater; 2. Breached cones with one open-rim crater; 3. Complex cones with two or more interconnected craters and overlapping cones; 4. Other edifices without a distinguishable crater or cone shape (e.g. spatter mounds and levees along eruptive fissures). The results show that cones are distributed in clusters and along alignments, in some cases parallel with the regional tectonic orientations. Contrasts in the volumes of cones positioned on the rift shoulders compared to those located on the rift valley floor can possibly be attributed to contrasts in continental crust thickness. Furthermore, higher average cone slopes in the East-VVP (Bufumbira zone) and central-VVP cone clusters suggest

  1. Giant polygons and mounds in the lowlands of Mars: signatures of an ancient ocean?

    Science.gov (United States)

    Oehler, Dorothy Z; Allen, Carlton C

    2012-06-01

    This paper presents the hypothesis that the well-known giant polygons and bright mounds of the martian lowlands may be related to a common process-a process of fluid expulsion that results from burial of fine-grained sediments beneath a body of water. Specifically, we hypothesize that giant polygons and mounds in Chryse and Acidalia Planitiae are analogous to kilometer-scale polygons and mud volcanoes in terrestrial, marine basins and that the co-occurrence of masses of these features in Chryse and Acidalia may be the signature of sedimentary processes in an ancient martian ocean. We base this hypothesis on recent data from both Earth and Mars. On Earth, 3-D seismic data illustrate kilometer-scale polygons that may be analogous to the giant polygons on Mars. The terrestrial polygons form in fine-grained sediments that have been deposited and buried in passive-margin, marine settings. These polygons are thought to result from compaction/dewatering, and they are commonly associated with fluid expulsion features, such as mud volcanoes. On Mars, in Chryse and Acidalia Planitiae, orbital data demonstrate that giant polygons and mounds have overlapping spatial distributions. There, each set of features occurs within a geological setting that is seemingly analogous to that of the terrestrial, kilometer-scale polygons (broad basin of deposition, predicted fine-grained sediments, and lack of significant horizontal stress). Regionally, the martian polygons and mounds both show a correlation to elevation, as if their formation were related to past water levels. Although these observations are based on older data with incomplete coverage, a similar correlation to elevation has been established in one local area studied in detail with newer higher-resolution data. Further mapping with the latest data sets should more clearly elucidate the relationship(s) of the polygons and mounds to elevation over the entire Chryse-Acidalia region and thereby provide more insight into this

  2. Heard Island and McDonald Islands Acoustic Plumes: Split-beam Echo sounder and Deep Tow Camera Observations of Gas Seeps on the Central Kerguelen Plateau

    Science.gov (United States)

    Watson, S. J.; Spain, E. A.; Coffin, M. F.; Whittaker, J. M.; Fox, J. M.; Bowie, A. R.

    2016-12-01

    Heard and McDonald islands (HIMI) are two active volcanic edifices on the Central Kerguelen Plateau. Scientists aboard the Heard Earth-Ocean-Biosphere Interactions voyage in early 2016 explored how this volcanic activity manifests itself near HIMI. Using Simrad EK60 split-beam echo sounder and deep tow camera data from RV Investigator, we recorded the distribution of seafloor emissions, providing the first direct evidence of seabed discharge around HIMI, mapping >244 acoustic plume signals. Northeast of Heard, three distinct plume clusters are associated with bubbles (towed camera) and the largest directly overlies a sub-seafloor opaque zone (sub-bottom profiler) with >140 zones observed within 6.5 km. Large temperature anomalies did not characterize any of the acoustic plumes where temperature data were recorded. We therefore suggest that these plumes are cold methane seeps. Acoustic properties - mean volume backscattering and target strength - and morphology - height, width, depth to surface - of plumes around McDonald resembled those northeast of Heard, also suggesting gas bubbles. We observed no bubbles on extremely limited towed camera data around McDonald; however, visibility was poor. The acoustic response of the plumes at different frequencies (120 kHz vs. 18 kHz), a technique used to classify water column scatterers, differed between HIMI, suggestiing dissimilar target size (bubble radii) distributions. Environmental context and temporal characteristics of the plumes differed between HIMI. Heard plumes were concentrated on flat, sediment rich plains, whereas around McDonald plumes emanated from sea knolls and mounds with hard volcanic seafloor. The Heard plumes were consistent temporally, while the McDonald plumes varied temporally possibly related to tides or subsurface processes. Our data and analyses suggest that HIMI acoustic plumes were likely caused by gas bubbles; however, the bubbles may originate from two or more distinct processes.

  3. Backscattering and geophysical features of volcanic ridges offshore Santa Rosalia, Baja California Sur, Gulf of California, Mexico

    Science.gov (United States)

    Fabriol, Hubert; Delgado-Argote, Luis A.; Dañobeitia, Juan José; Córdoba, Diego; González, Antonio; García-Abdeslem, Juan; Bartolomé, Rafael; Martín-Atienza, Beatriz; Frias-Camacho, Víctor

    1999-11-01

    Volcanic ridges formed by series of volcanic edifices are identified in the central part of the Gulf of California, between Isla Tortuga and La Reforma Caldera-Santa Rosalı´a region. Isla Tortuga is part of the 40-km-long Tortuga Volcanic Ridge (TVR) that trends almost perpendicular to the spreading center of the Guaymas Basin. The Rosalı´a Volcanic Ridge (RVR), older than TVR, is characterized by volcanic structures oriented towards 310°, following a fracture zone extension and the peninsular slope. It is interpreted that most of the aligned submarine volcanic edifices are developed on continental crust while Isla Tortuga lies on oceanic-like crust of the Guaymas Basin. From a complete Bouguer anomaly map, it is observed that the alignments of gravity highs trending 310° and 290° support the volcanic and subvolcanic origin of the bathymetric highs. Volcanic curvilinear structures, lava flows and mounds were identified from backscattering images around Isla Tortuga and over a 400-m high (Vı´rgenes High), where the TVR and the RVR intersect. A refraction/wide-angle seismic profile crossing perpendicular to the Vı´rgenes High, together with gravity and magnetic data indicate the presence of shallow intrusive bodies presumably of basaltic or andesitic composition. It is inferred that most volcanic edifices along the ridges have similar internal structures. We suggest that the growth of different segments of the ridges have a volcano-tectonic origin. The older RVR lies along the extension of a fracture zone and it probably is associated with Pliocene NE-SW extension.

  4. Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

    Science.gov (United States)

    Soare, Richard J.; Conway, Susan J.; Pearce, Geoffrey D.; Costard, François; Séjourné, Antoine

    2013-08-01

    At the middle latitudes of Utopia Planitia (˜35-45°N; ˜65-101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ˜10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ˜0.16. The plain's terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice-dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain's terrain share a common ice-dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice-dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest.

  5. Hydrocarbon- Generating Model of the Area Covered With Volcanic Rock

    Institute of Scientific and Technical Information of China (English)

    Guo Zhanqian; Zhang Yuwei

    2000-01-01

    The distribution of Oil & gas fields shows their close relationship with the most active tectonic regions. This is not a coincidence but having a scientific reasons. The crustal active regions, refer to the places where the active natural earthquake, volcanic activities, underground water happened, and the areas of the leaking off of natural gas to the surface of the crust. The magma of volcanic activities brings the organic "kitchen range body" hydrocarbon- generating model and inorganic genetic hydrocarbon to the regions covered by volcanic rock. Underground water brings a catalytic hydrocarbongenerating model for organic matter, and the leaking- off of H2 and CO2 contributes a synthetic hydrocarbon - generating model. Volcanic activities bring the assemblage of Source, Reservoir and Seal formed by the sediments and magma the sedimentary basins, and the hydrocarbon - generating system with a "water - volcano" binary structure is formed. All these conditions are favorable and excellent for the formation of oil & gas fields. The distribution of American oil & gas fields have very close relationship with the mines of Fe, Mn, Ct, Mo, W and V, deposits of Zn, Cu, V, Pb, Al and Hg, and the deposits of fluorite, sulfur, potassium salt, phosphate and halite, and the distribution of sulfate- chloride of river water. The reason why few oil & gas fields discovered in the regions covered by volcanic rock in western America maybe because of the view of "inconsistency between petroleum and volcano". Further more, It's very difficult to carry out a geophysical exploration in such kinds of regions.This paper examined a few hydrocarbon-generating models (systems) mentioned above and came up with some fresh ideas on the exploration in the areas covered with volcanic rocks.

  6. Exploring Hawaiian Volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-02-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai`i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO's founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists' understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  7. Exploring Hawaiian volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-01-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai‘i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO’s founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists’ understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  8. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2016-01-01

    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  9. California's Vulnerability to Volcanic Hazards: What's at Risk?

    Science.gov (United States)

    Mangan, M.; Wood, N. J.; Dinitz, L.

    2015-12-01

    California is a leader in comprehensive planning for devastating earthquakes, landslides, floods, and tsunamis. Far less attention, however, has focused on the potentially devastating impact of volcanic eruptions, despite the fact that they occur in the State about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have occurred in the past 1,000 years—most recently in northern California (Lassen Peak 1914 to 1917)—and future volcanic eruptions are inevitable. The likelihood of renewed volcanism in California is about one in a few hundred to one in a few thousand annually. Eight young volcanoes, ranked as Moderate to Very High Threat [1] are dispersed throughout the State. Partially molten rock (magma) resides beneath at least seven of these—Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, and Salton Buttes— causing earthquakes, toxic gas emissions, hydrothermal activity, and (or) ground deformation. Understanding the hazards and identifying what is at risk are the first steps in building community resilience to volcanic disasters. This study, prepared in collaboration with the State of California Governor's Office of Emergency Management and the California Geological Survey, provides a broad perspective on the State's exposure to volcano hazards by integrating mapped volcano hazard zones with geospatial data on at-risk populations, infrastructure, and resources. The study reveals that ~ 16 million acres fall within California's volcano hazard zones, along with ~ 190 thousand permanent and 22 million transitory populations. Additionally, far-field disruption to key water delivery systems, agriculture, utilities, and air traffic is likely. Further site- and sector-specific analyses will lead to improved hazard mitigation efforts and more effective disaster response and recovery. [1] "Volcanic Threat and Monitoring Capabilities

  10. The CARBONATE project: Mid-latitude Carbonate Systems - Complete Sequences from Cold-Water Coral Carbonate Mounds in the Northeast Atlantic

    Science.gov (United States)

    Wheeler, A.; Freiwald, A.; Hebbeln, D.; Swennen, R.; van Weering, T.; de Haas, H.; Dorschel, B.

    2007-12-01

    Up to now the carbonate stored in carbonate mounds has not been considered in any global carbonate budget or linked to any global carbon budget involving greenhouse gases. A major challenge exists to quantify the amount and flux of carbon stored by these newly discovered areas of enhanced carbonate accumulation in intermediate water depth. Furthermore, investigations so far reveal that all mounds possess different growth histories depending on the environmental setting and the involved faunal associations. Unfortunately, existing cores only penetrated the upper few meters of the mounds thus limiting mound research to the very late stage of mound development. Access to the longer sequences preserved in giant carbonate mounds was overcome in May 2005 when the IODP Expedition 307 (Porcupine Mound Drilling) recovered complete sedimentary records from one 155 m high "Challenger Mound" in the Porcupine Seabight west off Ireland. Furthermore, EU-FP projects have revealed late stage history of giant mounds in different settings showing that different mounds respond in different ways to environmental forcing factors with no one mound being typical of all. CARBONATE will drill complete sequences through a number of mounds in differing environmental settings using the portable drill rig MeBo (University of Bremen). By understanding how biogeochemical processes control the development of these carbonate mounds and their response to climate change, we will make an important step in quantifying their role as mid-latitude carbonate sinks. In the end, a better understanding of the processes involved in mound formation and development may also result in new views on fossil analogues many of which are less accessible hydrocarbon reservoirs.

  11. Temporal Characterization of Hydrates System Dynamics beneath Seafloor Mounds. Integrating Time-Lapse Electrical Resistivity Methods and In Situ Observations of Multiple Oceanographic Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Lutken, Carol [Univ. of Mississippi, Oxford, MS (United States); Macelloni, Leonardo [Univ. of Mississippi, Oxford, MS (United States); D' Emidio, Marco [Univ. of Mississippi, Oxford, MS (United States); Dunbar, John [Univ. of Mississippi, Oxford, MS (United States); Higley, Paul [Univ. of Mississippi, Oxford, MS (United States)

    2015-01-31

    This study was designed to investigate temporal variations in hydrate system dynamics by measuring changes in volumes of hydrate beneath hydrate-bearing mounds on the continental slope of the northern Gulf of Mexico, the landward extreme of hydrate occurrence in this region. Direct Current Resistivity (DCR) measurements were made contemporaneously with measurements of oceanographic parameters at Woolsey Mound, a carbonate-hydrate complex on the mid-continental slope, where formation and dissociation of hydrates are most vulnerable to variations in oceanographic parameters affected by climate change, and where changes in hydrate stability can readily translate to loss of seafloor stability, impacts to benthic ecosystems, and venting of greenhouse gases to the water-column, and eventually, the atmosphere. We focused our study on hydrate within seafloor mounds because the structurally-focused methane flux at these sites likely causes hydrate formation and dissociation processes to occur at higher rates than at sites where the methane flux is less concentrated and we wanted to maximize our chances of witnessing association/dissociation of hydrates. We selected a particularly well-studied hydrate-bearing seafloor mound near the landward extent of the hydrate stability zone, Woolsey Mound (MC118). This mid-slope site has been studied extensively and the project was able to leverage considerable resources from the team’s research experience at MC118. The site exhibits seafloor features associated with gas expulsion, hydrates have been documented at the seafloor, and changes in the outcropping hydrates have been documented, photographically, to have occurred over a period of months. We conducted observatory-based, in situ measurements to 1) characterize, geophysically, the sub-bottom distribution of hydrate and its temporal variability, and 2) contemporaneously record relevant environmental parameters (temperature, pressure, salinity, turbidity, bottom currents) to

  12. Acoustic scattering from mud volcanoes and carbonate mounds.

    Science.gov (United States)

    Holland, Charles W; Weber, Thomas C; Etiope, Giuseppe

    2006-12-01

    Submarine mud volcanoes occur in many parts of the world's oceans and form an aperture for gas and fluidized mud emission from within the earth's crust. Their characteristics are of considerable interest to the geology, geophysics, geochemistry, and underwater acoustics communities. For the latter, mud volcanoes are of interest in part because they pose a potential source of clutter for active sonar. Close-range (single-interaction) scattering measurements from a mud volcano in the Straits of Sicily show scattering 10-15 dB above the background. Three hypotheses were examined concerning the scattering mechanism: (1) gas entrained in sediment at/near mud volcano, (2) gas bubbles and/or particulates (emitted) in the water column, (3) the carbonate bio-construction covering the mud volcano edifice. The experimental evidence, including visual, acoustic, and nonacoustic sensors, rules out the second hypothesis (at least during the observation time) and suggests that, for this particular mud volcano the dominant mechanism is associated with carbonate chimneys on the mud volcano. In terms of scattering levels, target strengths of 4-14 dB were observed from 800 to 3600 Hz for a monostatic geometry with grazing angles of 3-5 degrees. Similar target strengths were measured for vertically bistatic paths with incident and scattered grazing angles of 3-5 degrees and 33-50 degrees, respectively.

  13. Multicomponent Seismic Analysis and Calibration to Improve Recovery from Algal Mounds: Application to the Roadrunner/Towaoc area of the Paradox Basin, UTE Mountain UTE Reservation, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Joe Hachey

    2007-09-30

    of this upgrade to nine components was to provide additional shear wave component data that might prove useful in delineating internal mound reservoir attributes. Also, Red Willow extended the P-wave portion of the survey to the northwest of the original 6 mi{sup 2} (15.6 km{sup 2}) 3D9C area in order to extend coverage further to the northwest to the Marble Wash area. In order to accomplish this scope of work, 3D9C seismic data set covering two known reservoirs was acquired and processed. Three-dimensional, zero-offset vertical seismic profile (VSP) data was acquired to determine the shear wave velocities for processing the sh3Dseismic data. Anisotropic velocity, and azimuthal AVO processing was carried out in addition to the conventional 3D P-wave data processing. All P-, PS- and S-wave volumes of the seismic data were interpreted to map the seismic response. The interpretation consisted of conventional cross-plots of seismic attributes vs. geological and reservoir engineering data, as well as multivariate and neural net analyses to assess whether additional resolution on exploration and engineering parameters could be achieved through the combined use of several seismic variables. Engineering data in the two reservoirs was used to develop a combined lithology, structure and permeability map. On the basis of the seismic data, a well was drilled into the northern mound trend in the project area. This well, Roadrunner No.9-2, was brought into production in late April 2006 and continues to produce modest amounts of oil and gas. As of the end of August 2007, the well has produced approximately 12,000 barrels of oil and 32,000 mcf of gas. A static reservoir model was created from the seismic data interpretations and well data. The seismic data was tied to various markers identified in the well logs, which in turn were related to lithostratigraphy. The tops and thicknesses of the various units were extrapolated from well control based upon the seismic data that was

  14. Young Volcanism on 20 Million Year Old Seafloor: The DISCOL Area, Nazca Plate.

    Science.gov (United States)

    Devey, C. W.; Boetius, A.; Kwasnitschka, T.; Augustin, N.; Yeo, I. A.; Greinert, J.

    2016-12-01

    Volcanism in the ocean basins is traditionally assumed to occur only at the plate margins (mid-ocean ridges, subduction zones, possibly also transform boundaries) and areas of intraplate hotspot activity related to thermal plumes in the mantle. As a result, abyssal areas away from hotspots are seldom explored systematically for signs of volcanism and are generally regarded as volcanically "dead". Here we present serendipitous results from the Peru Basin, a site of Mn-nodule accumulation which was targetted in 1989 for a large-scale disturbance experiment (the DISCOL experiment) to simulate the effects of seabed nodule mining. The area is truly intraplate - it is 700 km from the south American subduction zone or the Galapagos Islands and 2000 km from the East Pacific Rise. A return trip to DISCOL in 2015 to assess the extent of environmental recovery also included a remotely-operated underwater vehicle (ROV) dive on a small (300m high) seamount adjacent to the Mn-nodule field. ROV video records show the seamount is generally heavily sedimented but has a small (100x150m) pillow mound and an area of indurated calcareous sediments apparently cut by basaltic dykes near its summit. The summit is also cut by N-S and E-W-trending faults, some with up to 20m of throw, whose scarps expose thick sedimentary sequences. The virtual absence of sediment covering the pillows or dyke outcrops suggest that they are very recent - the thick sediment pile exposed on the fault scarps suggests that they were erupted on top of an old seamount. Regionally, acoustic data (bathymetry and backscatter from the ship-mounted multibeam system) shows several other seamounts in the region which may have experienced recent volcanic activity, although no sign of a linear volcanic chain is seen. Taken together, these observations suggest that, even at age 20Ma, the Nazca Plate is volcanically active.

  15. Volcanism on Mars. Chapter 41

    Science.gov (United States)

    Zimbelman, J. R.; Garry, W. B.; Bleacher, J. E.; Crown, D. A.

    2015-01-01

    Spacecraft exploration has revealed abundant evidence that Mars possesses some of the most dramatic volcanic landforms found anywhere within the solar system. How did a planet half the size of Earth produce volcanoes like Olympus Mons, which is several times the size of the largest volcanoes on Earth? This question is an example of the kinds of issues currently being investigated as part of the space-age scientific endeavor called "comparative planetology." This chapter summarizes the basic information currently known about volcanism on Mars. The volcanoes on Mars appear to be broadly similar in overall morphology (although, often quite different in scale) to volcanic features on Earth, which suggests that Martian eruptive processes are not significantly different from the volcanic styles and processes on Earth. Martian volcanoes are found on terrains of different age, and Martian volcanic rocks are estimated to comprise more than 50% of the Martian surface. This is in contrast to volcanism on smaller bodies such as Earth's Moon, where volcanic activity was mainly confined to the first half of lunar history (see "Volcanism on the Moon"). Comparative planetology supports the concept that volcanism is the primary mechanism for a planetary body to get rid of its internal heat; smaller bodies tend to lose their internal heat more rapidly than larger bodies (although, Jupiter's moon Io appears to contradict this trend; Io's intense volcanic activity is powered by unique gravitational tidal forces within the Jovian system; see "Volcanism on Io"), so that volcanic activity on Mars would be expected to differ considerably from that found on Earth and the Moon.

  16. Meteoritic Metal Beads from the Havana, Illinois, Hopewell Mounds: A Source in Minnesota and Implications for Trade and Manufacture

    Science.gov (United States)

    McCoy, T. J.; Marquardt, A. E.; Vicenzi, E. P.; Ash, R. D.; Wasson, J. T.

    2008-03-01

    Meteoritic metal beads from an Illinois Hopewell burial mound (~350 BCE) are pieces of the Anoka, Minnesota iron, which were worked in Ohio or Michigan and transported to Illinois as a finished product.

  17. Growth and form of the mound in Gale Crater, Mars: Slope-wind enhanced erosion and transport

    CERN Document Server

    Kite, Edwin S

    2012-01-01

    Gale crater, the landing site of the Curiosity Mars rover, hosts a 5 kilometer high layered mound of uncertain origin which may represent an important archive of the planet's past climate. Although widely considered to be an erosional remnant of a once crater-filling unit, we combine structural measurements and a new model of formation to show how this mound may have grown in place near the center of the crater under the influence of topographic slope-induced winds. This mechanism implicates airfall-dominated deposition with a limited role for lacustrine or fluvial activity in the formation of the Gale mound, and is not favorable for the preservation of organic carbon. Slope-wind enhanced erosion and transport is widely applicable to a range of similar sedimentary mounds found across the Martian surface.

  18. Volcanic Ash Nephelometer Probe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes may enable unprecedented observations of...

  19. Multi-beam backscatter data to characterize the mound and channel provinces of the Porcupine Seabight - northeast Atlantic margin

    Science.gov (United States)

    Beyer, A.; Chakraborty, B.; Schenke, H. W.

    2003-04-01

    Large scale oceanographic explorations are presently continuing around the Porcupine Seabight area, which is located towards the south-west Ireland. This area is an embayment of the north Atlantic continental margins. It's importance due to the dominant hydrocarbon resources are not unknown, and on-going experiments are important due to the involvement of higher order variability (in terms of physical and geological settings) around this area. Multi-beam angular backscatter study to characterize the eastern slope seafloor of the Porcupine Seabight is initiated first time. Backscatter data acquired from twenty-nine locations of the carbonate mounds and associated buried mounds (Belgica province), and channel seafloors like: Kings channel and Gollum channels are analysed in this paper. Processing details of the angular backscatter data was carried out to apply the scattering models to determine seafloor roughness. Employed normalization to the angular backscatter data to obtain shape invariant seafloor indicate distinct grey levels for mound, buried mound, and various channel seafloors (four distinct types of seafloors) within the backscatter dynamic range of 12 dB. The backscatter levels are the highest for the mound areas followed by the buried mounds, channel seafloor, and inter-channel areas. Present study was further substantiated by employing a semi-empirical method to determine the shape aspects of the area backscatter strengths. Estimated three parameters like: predicted 20 degree angular backscatter response, slope and coefficient of variations of the angular backscatter responses are computed to understand general seafloor characteristics of the varying area seafloor. The use of Helmholtz-Kirchhoff's angular backscatter theory which is a functional of the power law are carried out to estimate sea water floor interface roughness parameters. The sediment volume inhomogeneity parameters are also determined by use of curve fitting to the overlaying interface

  20. Tobi sidescan sonar mapping of carbonate mound provinces and channel heads in the Porcupine Seabight, W of Ireland

    Science.gov (United States)

    Huvenne, V.; van Rooij, D.; Wheeler, A.; de Haas, H.; Henriet, J. P.

    2003-04-01

    A large-scale sidescan sonar survey, using the 30 kHz TOBI system of the SOC, was carried out in summer 2002 over the carbonate mound provinces of the Porcupine Seabight and Rockall Trough, W of Ireland (EASSS III contract HPRI-CT-1999-00047, survey partly on behalf of the Porcupine Studies Group). The survey in the Porcupine Seabight focused on the Hovland-Magellan province in the north and the Belgica province on the eastern flank of the basin. Furthermore a reconnaissance track was added over the canyon heads of the Gollum Channel System further south in the Seabight. Each area has different characteristics. The Hovland-Magellan province shows a very homogeneous backscatter in the sidescan mosaics, indicating a quiet depositional environment. Mounds appear as sharp features with a strong backscatter and an acoustic shadow. Some Hovland mounds form multiple, ridge-like structures of more than a km in length. The Magellan mounds are nearly all buried, but leave subtle topographic effects at the seafloor. The Belgica mound province is characterised by much less homogeneous backscatter and a steeper seafloor slope. The mounds are placed en echelon along the slope and are bound to the W by a blind channel. Smaller down-slope channels are also found between the mounds. Many small, high-backscatter features, interpreted as incipient ('Moira') mounds have been found in this province. Striations in the blind channel, and higher up on the slope of the Belgica province indicate the influence of high current speeds. Pockmarks have been found just south of the Belgica province. The Gollum Channels are steep-flanked, U- or V-shaped channels of ca. 200 m deep. Their steep walls are cut by gullies and feeder channels, and evidence of slope failures is present. Lineations and high-backscatter patches are found on some of the channel floors.

  1. Volcanic Eruptions and Climate

    Science.gov (United States)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  2. A terrestrial weathering and wind abrasion analog for mound and moat morphology of Gale crater, Mars

    Science.gov (United States)

    Chan, Marjorie A.; Netoff, Dennis I.

    2017-05-01

    A striking feature of Gale crater is the 5.5 km high, central layered mound called Mount Sharp (Aeolis Mons)—the major exploration target for the Mars Science Laboratory rover, Curiosity. Within the 154 km diameter crater, low plains (Aeolis Palous) resemble a moat surrounding Mount Sharp. There is a similar terrestrial analog in the Jurassic Navajo Sandstone of southern Utah, USA, where a distinctive weathering pit 60 m wide by 20 m deep contains a central pillar/mound and moat. Strong regional and local winds are funneled to amplify their velocity and produce a Venturi effect that sculpts the pit via wind abrasion. Although the Navajo pit is orders of magnitude smaller than Gale crater, both show comparable morphologies accompanied by erosional wind features. The terrestrial example shows the impact of weathering and the ability of strong winds and vortices to shape lithified sedimentary rock over long periods of time.

  3. Experimental Study on Friction Coefficient Between Concrete and the Top Surface of Rubble Mound Foundation

    Institute of Scientific and Technical Information of China (English)

    LI Yan-bao; JIANG Xue-lian; GUO Hong-yi

    2005-01-01

    Experimental studies on the friction coefficient between concrete and the top surface of a rubble mound foundation in China are reviewed. Through comparison of different test results, the development of this research is comprehensively analyzed. An experiment is carried out in the condition similar to prototype. The process curve of friction coefficient with the test block sliding is analyzed and a standard for determination of the friction coefficient is defined. The variation features of the friction coefficient are analyzed on the basis of the present experimental results and other studies in China. It is shown that the friction coefficient between concrete and the top surface of a rubble mound foundation decreases with the increase of the foundation pressure, and the friction coefficient for a very fine leveling bed is smaller than that for a fine leveling bed.

  4. Sources of Sulfate Found in Mounds and Lakes at the Lewis Cliffs Ice Tongue, Transantarctic

    Science.gov (United States)

    Socki, Richard; Sun, Tao; Harvey, Ralph P.; Bish, David L.; Tonui, Eric; Bao, Huiming; Niles, Paul B.

    2012-01-01

    Massive but highly localized Na-sulfate mounds (mirabilite, Na2SO4.10H2O) have been found at the terminal moraine of the Lewis Cliffs Ice Tongue (LCIT), Antarctica. (Sigma)34S and (Sigma)18O values of LCIT mirabilite range from +48.8 to +49.3% (CDT), and -16.6 to -17.1% (V-SMOW), respectively, while (Delta)17O average -0.37% (V-SMOW). LCIT mirabilite mounds are isotopically different from other mirabilite mounds found in coastal regions of Antarctica, which have isotope values close to seawater compositions. (Sigma)18O and (Delta)17O values suggest the incorporation of isotopically light glacial water. Data point to initial sulfate formation in an anoxic water body, either as a stratified anoxic deep lake on the surface, a sub-glacial water reservoir, or a sub-glacial lake. Several surface lakes of varying size are also present within this region of the LCIT, and in some cases are adjacent to the mirabilite mounds. O and D isotope compositions of surface lakes confirm they are derived from a mixture of glacial ice and snow that underwent moderate evaporation. (Sigma)18O and (Sigma)D (V-SMOW) values of snow, ice, and lake water range from -64.2 to -29.7%, and -456.0 to -231.7%, respectively. However, the isotope chemistry of these surface lakes is extremely different from the mounds. Dissolved SO4-2 (Sigma)34S and (Sigma)18O values range from +12.0 to +20.0% and -12.8 to -22.2% (the most negative (Sigma)18O of terrestrial sulfate ever reported), respectively, with sulfate (Delta)17O ranging from +0.93 to 2.24%. Ion chromatography data show that lake water is fresh to brackish in origin, with TDS less than 1500 ppm, and sulfate concentration less than 431 ppm. Isotope and chemical data suggest that these lakes are unlikely the source of the mirabilite mounds. We suggest that lake water sulfate is potentially composed of a mixture of atmospheric sulfate and minor components of sulfate of weathering origin, much like the sulfate in the polar plateau soils of the Mc

  5. Cold-water coral growth and mound formation on the Pen Duick Escarpment, Gulf of Cadiz

    Science.gov (United States)

    Mienis, Furu; de Stigter, Henko C.; de Haas, Henk; Groot, Diane; Frank, Norbert; van Weering, Tjeerd C. E.

    2010-05-01

    Abundant skeletal remains of cold-water corals in sediments around the Pen Duick Escarpment, southern Gulf of Cadiz, suggest that corals thrived in the area in a relatively recent past. Cold-water coral carbonate mounds with heights of up to 60 m are found at about 550 m water depth on the edge of an elevation delimited by the Pen Duick Escarpment. Coral debris is abundantly present in the sediment on the carbonate mounds as well as on the escarpment, with Lophelia pertusa and Madrepora oculata as most common species. However, living coral is rare, and a mud drape of a few cm to tens of cm thick is usually found covering the coral-bearing sediment. On and off mound sediment cores are presently investigated in detail to determine the timing of the decline of cold-water coral communities on the Pen Duick Escarpment. Planktonic foraminifera oxygen isotope stratigraphy and U/Th datings of coral debris from the on mound core show that the main framework building cold-water corals Lophelia pertusa and Madrepora oculata were present on the mound during glacial periods (Marine Isotope Stage 2, 6 and 8) and the early Holocene, but absent during the late Holocene. During glacial periods a dense framework of cold-water corals existed and sedimentation rates were high. Both on and off mound cores show low magnetic susceptibility values until marine isotope stage 3, after which values are increasing. A large hiatus is found between 36 and 141 kyr. Our finding that cold-water corals on Pen Duick escarpment occurred mostly during glacial times contrasts with that of cold-water corals on the Rockall Trough margins and in the Porcupine Seabight, where they seem to have mainly lived during interglacials. The reason for the late Holocene decline of cold-water corals on Pen Duick escarpment is still a matter of speculation. Observations made with CTD and long-term deployment of benthic landers indicate activity of internal waves in the area with semi-diurnal periodicity, inducing

  6. Methane fluxes from the mound-building termite species of North Australian savannas

    Science.gov (United States)

    Jamali, H.; Livesely, S. J.; Arndt, S. K.; Dawes-Gromadzki, T.; Cook, G. D.; Hutley, L.

    2009-04-01

    Termites are estimated to contribute 3-19% to the global methane emissions. These estimates have large uncertainties because of the limited number of field-based studies and species studied, as well as issues of diel and seasonal variation. We measured methane fluxes from four common mound-building termite species (Microcerotermes nervosus, n=26; M. serratus, n=4; Tumulitermes pastinator, n=5; and Amitermes darwini, n=4) in tropical savannas near Darwin in the Northern Territory, Australia. Methane fluxes from replicated termite mounds were measured in the field using manual chambers with fluxes reported on a mound volume basis. Methane flux was measured in both wet and dry seasons and diel variation was investigated by measuring methane flux every 4 hours over a 24 hour period. Mound temperature was measured concurrently with flux to examine this relationship. In addition, five M. nervosus mounds removed from the field and incubated under controlled temperature conditions over a 24 hour period to remove the effect of varying temperature. During the observation campaigns, mean monthly minimum and maximum temperatures for February (wet season) were 24.7 and 30.8°C, respectively, and were 20.1 to 31.4 °C in June (dry season). Annual rainfall in 2008 for Darwin was 1970.1 mm, with a maximum of 670 mm falling in February and no rain in May and June. Methane fluxes were greatest in the wet season for all species, ranging from 265.1±101.1 (T. pastinator) to 2256.6±757.1 (M. serratus) µg CH4-C/m3/h. In the dry season, methane fluxes were at their lowest, ranging from 10.0±5.5 (T. pastinator) to 338.0±165.9 (M. serratus) µg CH4-C/m3/h. On a diel basis, methane fluxes were smallest at the coolest time of the day (~0700 hrs) and greatest at the warmest (~1400 hrs) for all species, and for both wet and dry seasons. Typical diel variation in flux from M. serratus dominated mounds ranged from 902.6±261.9 to 1392.1±408.1 µg CH4-C/m3/h in wet season and 99.6±57.4 to

  7. Island-dynamics model for mound formation: effect of a step-edge barrier.

    Science.gov (United States)

    Papac, Joe; Margetis, Dionisios; Gibou, Frederic; Ratsch, Christian

    2014-08-01

    We formulate and implement a generalized island-dynamics model of epitaxial growth based on the level-set technique to include the effect of an additional energy barrier for the attachment and detachment of atoms at step edges. For this purpose, we invoke a mixed, Robin-type, boundary condition for the flux of adsorbed atoms (adatoms) at each step edge. In addition, we provide an analytic expression for the requisite equilibrium adatom concentration at the island boundary. The only inputs are atomistic kinetic rates. We present a numerical scheme for solving the adatom diffusion equation with such a mixed boundary condition. Our simulation results demonstrate that mounds form when the step-edge barrier is included, and that these mounds steepen as the step-edge barrier increases.

  8. Macrofauna community inside and outside of the Darwin Mounds SAC, NE Atlantic

    Directory of Open Access Journals (Sweden)

    N. Serpetti

    2012-11-01

    Full Text Available Over the past two decades, growing concerns have been raised regarding the effects of towed fishing gears, such as trawls and dredges, on deep-sea biodiversity and ecosystem functioning. Trawling disturbs the benthic communities both physically and biologically, and can eliminate the most vulnerable organisms and modify habitat structure; chronically disturbed communities are often dominated by opportunistic species. The European Union is under obligation to designate a network of offshore Special Areas of Conservation (SACs and Marine Protected Areas (MPAs by the end of 2012 based on the perceived expectation that these networks will help protect marine biodiversity and that within these areas, faunal abundance and diversity will be higher than the surrounding fished areas.

    The Darwin Mounds, only discovered in 1998, are located in the Rockall Trough, NE Atlantic at a depth of ~ 1000 m. Deep-water trawling regularly took place in the region of the Darwin Mounds; however in 2004 the mounds were designated as the first offshore SAC in UK and the area is now closed to bottom trawling. As part of the HERMIONE programme the influence of human impact on the Oceans was one of the key themes and in June 2011, an investigation of the macrofaunal community structure at comparable sites both inside and outside of the Darwin Mound SAC was undertaken. Macrofaunal communities were found to differ significantly, with the difference mostly driven by changes in the abundance of polychaetes, crustaceans and nematodes whilst no significant differences were seen for the other phyla. Whereas overall macrofaunal abundance was higher outside the SAC compared to within, this pattern varies considerably between phyla. Diversity indices showed no significant differences between protected and unprotected sites. This could indicate that a few years of preservation are not enough time to determine a recovery by the macrofaunal community of cold-water ecosystems

  9. Parameters Influencing Wave Run-Up on a Rubble Mound Breakwater

    DEFF Research Database (Denmark)

    Walle, Björn Van de; Rouck, Julien De; Damme, Luc Van

    2002-01-01

    Full scale wave run-up measurements have been performed on the Zebrugge rubble mound breakwater. Wave run-up also has been investigated on various small scale models of the Zeebrugge breakwater. A significant difference between the results has been noticed. Additional small scale model testing ha...... of the wave run-up step gauge with respect to the armour unit pattern and the water level....

  10. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY 1976 and FY 1976A

    Energy Technology Data Exchange (ETDEWEB)

    Ruwe, A.H. Jr. (comp.)

    1977-06-06

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal years 1976 and 1976A (the period July 1, 1975 through September 30, 1976). Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers.

  11. Effects of Erosion from Mounds of Different Termite Genera on Distinct Functional Grassland Types in an African Savannah.

    Science.gov (United States)

    Gosling, Cleo M; Cromsigt, Joris P G M; Mpanza, Nokukhanya; Olff, Han

    A key aspect of savannah vegetation heterogeneity is mosaics formed by two functional grassland types, bunch grasslands, and grazing lawns. We investigated the role of termites, important ecosystem engineers, in creating high-nutrient patches in the form of grazing lawns. Some of the ways termites can contribute to grazing lawn development is through erosion of soil from aboveground mounds to the surrounding soil surface. This may alter the nutrient status of the surrounding soils. We hypothesize that the importance of this erosion varies with termite genera, depending on feeding strategy and mound type. To test this, we simulated erosion by applying mound soil from three termite genera (Macrotermes, Odontotermes, and Trinervitermes) in both a field experiment and a greenhouse experiment. In the greenhouse experiment, we found soils with the highest macro nutrient levels (formed by Trinervitermes) promoted the quality and biomass of both a lawn (Digitaria longiflora) and a bunch (Sporobolus pyramidalis) grass species. In the field we found that soils with the highest micro nutrient levels (formed by Macrotermes) showed the largest increase in cover of grazing lawn species. By linking the different nutrient availability of the mounds to the development of different grassland states, we conclude that the presence of termite mounds influences grassland mosaics, but that the type of mound plays a crucial role in determining the nature of the effects.

  12. Organic matter quality and supply to deep-water coral/mound systems of the NW European Continental Margin

    Science.gov (United States)

    Kiriakoulakis, K.; Freiwald, A.; Fisher, E.; Wolff, G. A.

    2007-02-01

    Comparison of five deep-water coral (DWC)/mound ecosystems along the European Continental Margin shows that suspended particulate organic matter (sPOM), a potential food source, is lipid rich and of high quality. However, there are differences between the sites. The Darwin and Pelagia Mounds (N. Rockall Trough and N. Porcupine Bank, respectively) have higher proportions of labile particulate lipids (including high proportions of polyunsaturated fatty acids) in the benthic boundary layer than Logachev, Hovland and Belgica Mounds (Rockall Bank, S. Porcupine Bank and Porcupine Seabight, respectively). The high quality sPOM could be transported downslope from the euphotic zone. There is some evidence for inter-annual variability at some sites (e.g. Hovland and Logachev Mounds) as large differences in suspended lipid and particulate organic carbon concentrations were observed over the sampling period. Elevated total organic carbon contents of sediments at mound sites, relative to control sites in some cases (particularly Darwin Mounds), probably reflect local hydrodynamic control and the trapping of sPOM by the DWC. Fresh POM can be relatively rapidly transferred to significant depth (up to 8 cm) through bioturbation that is evident at all sites. There is no clear evidence of present day hydrocarbon seepage at any of the sites.

  13. Do epigeal termite mounds increase the diversity of plant habitats in a tropical rain forest in peninsular Malaysia?

    Science.gov (United States)

    Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D

    2011-01-01

    The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation.

  14. Pre-operational safety appraisal Tritiated Scrap Recovery Facility, Mound facility

    Energy Technology Data Exchange (ETDEWEB)

    Dauby, J.J.; Flanagan, T.M.; Metcalf, L.W.; Rhinehammer, T.B.

    1996-07-01

    The purpose of this report is to identify, assess, and document the hazards which are associated with the proposed operation of the Tritiated Scrap Recovery Facility at Mound Facility. A Pre-operational Safety Appraisal is a requirement as stated in Department of Energy Order 5481.1, Safety Analysis and Review System. The operations to be conducted in the new Tritiated Scrap Waste Recovery Facility are not new, but a continuation of a prime mission of Mound`s i.e. recovery of tritium from waste produced throughout the DOE complex. The new facility is a replacement of an existing process started in the early 1960`s and incorporates numerous design changes to enhance personnel and environmental safety. This report also documents the safety of a one time operation involving the recovery of tritium from material obtained by the Department of Energy from the State of Arizona. This project will involve the processing of 240,000 curies of tritium contained in glass ampoules that were to be used in items such as luminous dial watches. These were manufactured by the now defunct American Atomics Corporation, Tucson, Arizona.

  15. Slope Stability Estimation of the Kościuszko Mound in Cracow

    Directory of Open Access Journals (Sweden)

    Wrana Bogumił

    2015-06-01

    Full Text Available In the paper, the slope stability problem of the Kościuszko Mound in Cracow, Poland is considered. The slope stability analysis was performed using Plaxis FEM program. The outer surface of the mound has complex geometry. The slope of the cone is not uniform in all directions, on the surface of the cone are pedestrian paths. Due to its complicated geometry it was impossible to do computing by Plaxis input pre-procesor. The initial element mesh was generated using Autodesk Autocad 3D and next it was updated by Plaxis program. The soil parameters were adopted in accordance with the detailed geological soil testing performed in 2012. Calculating model includes geogrids. The upper part was covered by MacMat geogrid, while the lower part of the Mound was reinforced using Terramesh Matt geogrid. The slope analysis was performed by successives reduction of φ /c parameters. The total multiplayer ΣMsf is used to define the value of the soil strength parameters. The article presents the results of slope stability before and after the rainfall during 33 days of precipitation in flood of 2010.

  16. Antarctic Mirabilite Mounds as Mars Analogs: The Lewis Cliffs Ice Tongue Revisited

    Science.gov (United States)

    Socki, Richard A.; Sun, Tao; Niles, Paul B.; Harvey, Ralph P.; Bish, David L.; Tonui, Eric

    2012-01-01

    It has been proposed, based on geomorphic and geochemical arguments, that subsurface water has played an important role in the history of water on the planet Mars [1]. Subsurface water, if present, could provide a protected and long lived environment for potential life. Discovery of gullies [2] and recurring slopes [3] on Mars suggest the potential for subsurface liquid water or brines. Recent attention has also focused on small (Tongue (LCIT) [6] in the Transantarctic Mountains, Antarctica, and are potential terrestrial analogs for mounds observed on the martian surface. The following characteristics distinguish LCIT evaporite mounds from other evaporite mounds found in Antarctic coastal environments and/or the McMurdo Dry Valleys: (1) much greater distance from the open ocean (approx.500 km); (2) higher elevation (approx.2200 meters); and (3) colder average annual temperature (average annual temperature = -30 C for LCIT [7] vs. 20 C at sea level in the McMurdo region [8]. Furthermore, the recent detection of subsurface water ice (inferred as debris-covered glacial ice) by the Mars Reconnaissance Orbiter [9] supports the use of an Antarctic glacial environment, particularly with respect to the mirabilite deposits described in this work, as an ideal terrestrial analog for understanding the geochemistry associated with near-surface martian processes. S and O isotopic compositions.

  17. On the Origin of the Dragon Image on the Plate from Shilovka Burial Mound

    Directory of Open Access Journals (Sweden)

    Liphanov Nicolay А.

    2017-07-01

    Full Text Available The author of the article analyzes an unique image of two opposed dragons engraved on a bone plate discovered in 1992 at barrow No.1 of Shilovka burial mound located on the right bank of the Volga river in Ulyanovsk Oblast (the excavations were conducted by R.S. Bagautdinov. The burial mound is related to the cattle breeding population of late 7th century. The article considers different hypotheses concerning the origin of these dragon images in the artistic traditions of various regions: China (A.V. Komar, D.G. Savinov, B. Totev, Pelevina, Central Asia (V.G. Kotov, V.E. Flyorova, India (N.A. Fonyakova. According to the author, this image has no apparent iconographic parallels in the traditions of these regions. Such analogues are found in the art of the Mediterranean where the ancient images of various mythological creatures exist alongside the image of the sea dragon “ketos” which later became part of the Christian tradition. The appearance of this monster in the images of the first half – middle of the 1st millennium A.D. is practically identical to the dragons from Shilovka burial mound. According to the author, certain impact on the formation of the considered dragon image was made by Iranian art.

  18. Bryan Mound InSAR Analysis U.S. Strategic petroleum Reserve.

    Energy Technology Data Exchange (ETDEWEB)

    Lord, Anna C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-06-01

    The U.S. Strategic Petroleum Reserve (SPR) is a stockpile of emergency crude oil to be tapped into if a disruption in the nation's oil supply occurs. The SPR is comprised of four salt dome sites. Subsidence surveys have been conducted either annually or biennially at all four sites over the life of the program. Monitoring of surface behavior is a first line defense to detecting possible subsurface cavern integrity issues. Over the life of the Bryan Mound site, subsidence rates over abandoned Cavern 3 have continuously been the highest at the site. In an effort to try and understand the subsurface dynamics, specifically over Bryan Mound Cavern 3, historic interferometric synthetic aperture radar (InSAR) data was acquired and processed by TRE Altamira. InSAR involves the processing of multiple satellite synthetic aperture radar scenes acquired across the same location of the Earth's surface at different times to map surface deformation. The analysis of the data has the ability to detect millimeters of motion spanning days, months, year and decades, across specific sites. The intent in regards to the Bryan Mound site was (1) to confirm the higher subsidence rates recorded over abandoned Cavern 3 indicated by land survey and (2) understand the regional surface behavior. This report describes the InSAR analysis results, how those results compare to the historical collection of land survey data, and what additional information the data has provided towards understanding the response recorded at the surface.

  19. Volcan Reventador's Unusual Umbrella

    Science.gov (United States)

    Chakraborty, P.; Gioia, G.; Kieffer, S. W.

    2005-12-01

    In the past two decades, field observations of the deposits of volcanoes have been supplemented by systemmatic, and sometimes, opportunistic photographic documentation. Two photographs of the umbrella of the December 3, 2002 eruption of Volcan Reventador, Ecuador, reveal a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. The material in the umbrella was being swept off a descending pyroclastic flow, and was, therefore, a co-ignimbrite cloud. We propose that the scallops are the result of a turbulent Rayleigh-Taylor (RT) instability with no precedents in volcanology. We ascribe the rare loss of buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. On the basis of the observed wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella of 4000 ~m2/s. This value is consistent with a previously obtained lower bound (200 ~m2/s, K. Wohletz, priv. comm., 2005). We do not know the fate of the material in the umbrella subsequent to the photos. The analysis suggests that the umbrella was negatively buoyant. Field work on the co-ignimbrite deposits might reveal whether or not the material reimpacted, and if so, where and whether or not this material was involved in the hazardous flows that affected the main oil pipeline across Ecuador.

  20. 2015 Volcanic activity in Alaska—Summary of events and response of the Alaska Volcano Observatory

    Science.gov (United States)

    Dixon, James P.; Cameron, Cheryl E.; Iezzi, Alexandra M.; Wallace, Kristi

    2017-09-28

    The Alaska Volcano Observatory (AVO) responded to eruptions, volcanic unrest or suspected unrest, and seismic events at 14 volcanic centers in Alaska during 2015. The most notable volcanic activity consisted of continuing intermittent ash eruptions from Cleveland and Shishaldin volcanoes in the Aleutian Islands. Two eruptive episodes, at Veniaminof and Pavlof, on the Alaska Peninsula ended in 2015. During 2015, AVO re-established the seismograph network at Aniakchak, installed six new broadband seismometers throughout the Aleutian Islands, and added a Multiple component Gas Analyzer System (MultiGAS) station on Augustine.

  1. Carbonate mound evolution and coral diagenesis viewed by U-series dating of deep water corals

    Science.gov (United States)

    Frank, N.; Ricard, E.; Blamart, D.; van der Land, C.; Colin, C.; Foubert, A.; van Rooij, D.; van Weering, T.

    2007-12-01

    U-series dating of constructional deep sea corals is a powerful tool to reconstruct the evolution of carbonate mound sediments driven by coral growth, sediment trapping and diagenesis. Here we have investigated in great detail the time framework of constructional corals such as L. pertusa and M. oculata on 5 different mounds of the eastern North Atlantic (on Rockall Bank and in Porcupine Seabight) taken at variable depth and location (610 to 880m water depth). Periods favorable for coral growth are the Holocene and prior interglacials such as marine isotope stage 5 and 7, while glacial coral growth seems inhibited or extremely reduced. Coral development is almost continuous throughout the Holocene since mound re-colonization about 10,500 years ago. Mound accumulation rates vary between 20 and 220 cm/kyr determined from the coral age - depth relationship in each core. Those changes are most likely driven by changes between horizontal and vertical mound accumulation, food supply and ocean circulation. In addition, coral dating allowed to identify an important erosional event recorded in core MD01-2455G from Rockall Bank. Here a 1m thick sediment layer containing ancient corals likely from the start of Holocene re-colonization was displaced (collapsed) from further upslope on top of younger corals of ~2500 to 3000 years age. Prior to the initiation of coral growth diagenesis occurred frequently resulting in (1) the construction of so called carbonate hardgrounds and/or (2) the dissolution of the pre-Holocene coral framework. Solely, the deepest selected core in Porcupine Seabight (MD01-2463G at 880m depth) reveals coral re-colonization on an undisturbed ancient reef structure that dates back to 250,000 years. Diagenesis of earlier coral reef generations leading to coral dissolution leads to a loss of magnetic susceptibility and open system behavior of the coral skeletons with respect to U-series dating. While the processes causing such diagenetic layers are barely

  2. A Four Dimensional Prospective of The Sedimentary Processes and Their Interactions With Ireland's Deep-water Coral Carbonate Mound Ecosystems: Belgica Carbonate Mound Province, Eastern Porcupine Seabight, NE Atlantic

    Science.gov (United States)

    Kozachenko, M.; Wheeler, A.; Beyer, A.; Blamart, D.; Masson, D.; Olu-Le Roy, K.

    Irish deep-water coral carbonate mound ecosystems form unique biological hotspots at c.600-900m water depths, whose sustainability is poorly understood. New side-scan sonar, multibeam, sub-bottom profiler and underwater video imagery supplemented with sedimentological material have been used to map the seabed sedimentary envi- ronment in the Belgica Carbonate Mounds province in the eastern Porcupine Seabight west of Ireland. These have given new insights on this unique ecosystem and its mobile sedimentary environment. The remote-sensed data integrated within a GIS provides information on sediment pathways and benthic current patterns within the study area. A facies map based on the high-resolution side-scan sonar coverage in conjunction with other geophysical, video and sample data highlights differing styles of sedimen- tary processes. Among these are mobile sand sheets, gravel ridges, barchan-like dunes and sediment wave fields. All these sediment bedforms, seen on underwater imagery, provide evidence for strong northward bottom currents or palaeocurrents, which show a strong interaction with the carbonate mounds, and have therefore influenced mound growth. Detailed analyses of sediment properties have been derived from seabed surface and 26m long contourite core MD99-2327 taken within an area of the side-scan sonar coverage. These were done in order to provided ground truthing of the remote-sensed data and quantify benthic current strength through time and sediment mobility thresh- olds. MD99-2327 provides a high resolution palaeoclimate record showing temporal pattern of variations in the bottom current strength during OIS 4 and 5a . The present study shows that benthic currents and sediment mobility play a major role on the carbonate mounds ecosystem vitality. However, accurate assessments of this influence requires further research to provide accurate data on coral abundance and mound growth rates, and therefore allow a comparison of temporal and spatial

  3. The hydrology and preservation condition in the flat-topped burial mound – Klangshøj at Vennebjerg in Vendsyssel

    DEFF Research Database (Denmark)

    Breuning-Madsen, Henrik; Henriksen, Peter Steen; Ågård Kristensen, Jeppe

    2017-01-01

    Klangshøj is a flat-topped burial mound similar to the Royal Jelling mounds, although smaller. The myths tell that a well has existed on top of the mound as at Jelling and a spring had flown at the base of the mound. In order to verify the myths and a similar hydrology in Klangshøj as found...... borings, where undecomposed plant remnants, occasionally greenish, were observed. A 14C-dating showed that the mound was built in the Viking Age. The hydrology in Klangshøj is the same as in the Jelling mounds, with a permeable bioturbation zone covering almost impermeable, distinct sod layers. This form...

  4. POTENTIAL IMPACT OF BLENDING RESIDUAL SOLIDS FROM TANKS 18/19 MOUNDS WITH TANK 7 OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Eibling, R; Erich Hansen, E; Bradley Pickenheim, B

    2007-03-29

    High level waste tanks 18F and 19F have residual mounds of waste which may require removal before the tanks can be closed. Conventional slurry pump technology, previously used for waste removal and tank cleaning, has been incapable of removing theses mounds from tanks 18F and 19F. A mechanical cleaning method has been identified that is potentially capable of removing and transferring the mound material to tank 7F for incorporation in a sludge batch for eventual disposal in high level waste glass by the Defense Waste Processing Facility. The Savannah River National Laboratory has been requested to evaluate whether the material transferred from tanks 18F/19F by the mechanical cleaning technology can later be suspended in Tank 7F by conventional slurry pumps after mixing with high level waste sludge. The proposed mechanical cleaning process for removing the waste mounds from tanks 18 and 19 may utilize a high pressure water jet-eductor that creates a vacuum to mobilize solids. The high pressure jet is also used to transport the suspended solids. The jet-eductor system will be mounted on a mechanical crawler for movement around the bottom of tanks 18 and 19. Based on physical chemical property testing of the jet-eductor system processed IE-95 zeolite and size-reduced IE-95 zeolite, the following conclusions were made: (1) The jet-eductor system processed zeolite has a mean and median particle size (volume basis) of 115.4 and 43.3 microns in water. Preferential settling of these large particles is likely. (2) The jet-eductor system processed zeolite rapidly generates settled solid yield stresses in excess of 11,000 Pascals in caustic supernates and will not be easily retrieved from Tank 7 with the existing slurry pump technology. (3) Settled size-reduced IE-95 zeolite (less than 38 microns) in caustic supernate does not generate yield stresses in excess of 600 Pascals in less than 30 days. (4) Preferential settling of size-reduced zeolite is a function of the amount of

  5. Geology and geothermal potential of Alid volcanic center, Eritrea, Africa

    Science.gov (United States)

    Clynne, Michael A.; Duffield, Wendell A.; Fournier, Robert O.; Giorgis, Leake W.; Janik, Cathy J.; Kahsai, Gabreab; Lowenstern, Jacob; Mariam, Kidane W.; Smith, James G.; Tesfai, Theoderos; ,

    1996-01-01

    Alid volcanic center, a 700-meter-tall mountain in Eritrea, northeast Africa, straddles the axis of an active crustal-spreading center called the Danakil Depression. Boiling-temperature fumaroles are common on Alid, and their gas compositions indicate a reservoir temperature of at least 250 ??C. The history of volcanism and the high reservoir temperature indicated by the Alid fumarole gases suggest that a geothermal resource of electrical grade lies beneath the mountain. Though drilling is needed to determine subsurface conditions, the process of dome formation and the ongoing crustal spreading can create and maintain fracture permeability in the hydrothermal system that feeds the Alid fumaroles.

  6. Linking benthic dynamics and cold-water coral occurrences: A high-resolution model study at three carbonate mound provinces in the NE Atlantic

    OpenAIRE

    2012-01-01

    We used the 3-D ocean circulation model with grid refinement ROMS-AGRIF to describe the hydrodynamic conditions at three cold-water coral provinces in the NE Atlantic (Logachev Mounds, Arc Mounds and Belgica Mounds). Modelled fields of currents, temperature and salinity were analysed for observed occurrences and presence/absence of living coral frameworks, living coral colonies within each province. The central model grid has a horizontal resolution of approximately 250 m, except for the Arc ...

  7. Volcanic studies at Katmai

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-31

    The Continental Scientific Drilling Program (CSDP) is a national effort supported by the Department of Energy, the US Geological Survey, and the National Science Foundation. One of the projects proposed for the CSDP consists of drilling a series of holes in Katmai National Park in Alaska to give a third dimension to the model of the 1912 eruption of Novarupta, and to investigate the processes of explosive volcanism and hydrothermal transport of metals (Eichelberger et al., 1988). The proposal for research drilling at Katmai states that ``the size, youth, elevated temperature, and simplicity of the Novarupta vent make it a truly unique scientific target.`` The National Park Service (NPS), which has jurisdiction, is sympathetic to aims of the study. However, NPS wishes to know whether Katmai is indeed uniquely suited to the research, and has asked the Interagency Coordinating Group to support an independent assessment of this claim. NPS suggested the National Academy of Sciences as an appropriate organization to conduct the assessment. In response, the National Research Council -- the working arm of the Academy -- established, under the aegis of its US Geodynamics Committee, a panel whose specific charge states: ``The proposed investigation at Katmai has been extensively reviewed for scientific merit by the three sponsoring and participating agencies. Thus, the scientific merit of the proposed drilling at Katmai is not at issue. The panel will review the proposal for scientific drilling at Katmai and prepare a short report addressing the specific question of the degree to which it is essential that the drilling be conducted at Katmai as opposed to volcanic areas elsewhere in the world.``

  8. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    The extensive Quaternary volcanism in the Payenia volcanic province, Mendoza, Argentina, is investigated in this study by major and trace element analyses, Sr, Nd, Hf and Pb-isotopic analyses and Zr-Hf isotope dilution data on samples from almost the entire province. The samples are mainly...... in basalts from all the studied volcanic fields in Payenia is signs of lower crustal contamination indicating assimilation of, in some cases, large amounts of trace element depleted, mafic, plagioclase-bearing rocks. The northern Payenia is dominated by backarc basalts erupted between late Pliocene to late...

  9. Paleoenvironmental reconstruction of microbial mud mound derived boulders from gravity-flow polymictic megabreccias (Visean, SW Spain)

    Science.gov (United States)

    Rodríguez-Martínez, M.; Moreno-González, I.; Mas, R.; Reitner, J.

    2012-07-01

    The Upper Visean outcrops from the Guadiato Valley (Córdoba, SW Spain) provide a well-preserved record of the mud mound factory, which was developed in a mainly siliciclastic synorogenic foreland basin during the oblique sinistral collision of two terranes (Ossa Morena and Central Iberian blocks). The first onset of mud mound development has been recorded as microbial mud mound-derived boulders in polymictic megabreccias as result of strong tectonic activity. The Upper Visean record from the Mississippian central band at Guadiato Valley starts with lower heterolithic units (up to 180 m thick) and shows two major tectonically-controlled cycles: a fining upwards interval (FU) followed by a coarsening upwards interval (CU). These cycles are linked to two active margins with gravelly fan delta development and different source areas. Mud mound-derived boulders occur in the CU interval and are formed by peloidal primary and secondary (reworked) automicrites and allomicrites, showing a diverse faunal and floral assemblage, although never as the main skeletal framebuilders. However, the observed coeval richness in sponges (lyssacinose hexactinellids and non-lithistid demosponges) and the diverse calcareous algae assemblage in mud mound derived boulders are not common in other Visean buildups. The growth cavities display changes in the geopetal relationships between fillings and the secondary cavities containing sand to gravel fillings reflecting a complex pre-boulder and mud mound derived boulder history. Detailed mapping, sampling, stratigraphic and microfacial analyses have allowed the reconstruction of the mud mounds sedimentary environment prior to the collapse, transport and emplacement as boulders with polymictic gravels.

  10. Models of Formation and Activity of Spring Mounds in the Mechertate-Chrita-Sidi El Hani System, Eastern Tunisia: Implications for the Habitability of Mars

    Directory of Open Access Journals (Sweden)

    Elhoucine Essefi

    2014-08-01

    Full Text Available Spring mounds on Earth and on Mars could represent optimal niches of life development. If life ever occurred on Mars, ancient spring deposits would be excellent localities to search for morphological or chemical remnants of an ancient biosphere. In this work, we investigate models of formation and activity of well-exposed spring mounds in the Mechertate-Chrita-Sidi El Hani (MCSH system, eastern Tunisia. We then use these models to explore possible spring mound formation on Mars. In the MCSH system, the genesis of the spring mounds is a direct consequence of groundwater upwelling, triggered by tectonics and/or hydraulics. As they are oriented preferentially along faults, they can be considered as fault spring mounds, implying a tectonic influence in their formation process. However, the hydraulic pressure generated by the convergence of aquifers towards the surface of the system also allows consideration of an origin as artesian spring mounds. In the case of the MCSH system, our geologic data presented here show that both models are valid, and we propose a combined hydro-tectonic model as the likely formation mechanism of artesian-fault spring mounds. During their evolution from the embryonic (early to the islet (“island” stages, spring mounds are also shaped by eolian accumulations and induration processes. Similarly, spring mounds have been suggested to be relatively common in certain provinces on the Martian surface, but their mode of formation is still a matter of debate. We propose that the tectonic, hydraulic, and combined hydro-tectonic models describing the spring mounds at MCSH could be relevant as Martian analogs because: (i the Martian subsurface may be over pressured, potentially expelling mineral-enriched waters as spring mounds on the surface; (ii the Martian subsurface may be fractured, causing alignment of the spring mounds in preferential orientations; and (iii indurated eolian sedimentation and erosional remnants are common

  11. Atmospheric oxygenation caused by a change in volcanic degassing pressure.

    Science.gov (United States)

    Gaillard, Fabrice; Scaillet, Bruno; Arndt, Nicholas T

    2011-10-12

    The Precambrian history of our planet is marked by two major events: a pulse of continental crust formation at the end of the Archaean eon and a weak oxygenation of the atmosphere (the Great Oxidation Event) that followed, at 2.45 billion years ago. This oxygenation has been linked to the emergence of oxygenic cyanobacteria and to changes in the compositions of volcanic gases, but not to the composition of erupting lavas--geochemical constraints indicate that the oxidation state of basalts and their mantle sources has remained constant since 3.5 billion years ago. Here we propose that a decrease in the average pressure of volcanic degassing changed the oxidation state of sulphur in volcanic gases, initiating the modern biogeochemical sulphur cycle and triggering atmospheric oxygenation. Using thermodynamic calculations simulating gas-melt equilibria in erupting magmas, we suggest that mostly submarine Archaean volcanoes produced gases with SO(2)/H(2)S atmosphere.

  12. Io. [theories concerning volcanic activity

    Science.gov (United States)

    Johnson, T. V.; Soderblom, L. A.

    1983-01-01

    A report on the continuing investigation of Io is presented. Gravitational resonance is discussed as the cause of Io's volcanism, and the volcanic activity is explained in terms of sulfur chemistry. Theories concerning the reasons for the two main types of volcanic eruptions on Io are advanced and correlated with geographical features of the satellite. The sulfur and silicate models of the calderas are presented, citing the strengths and weaknesses of each. Problems of the gravitational resonance theory of Io's heat source are then described. Finally, observations of Io planned for the Galileo mission are summarized.

  13. Rainsplash-induced mound development beneath desert shrubs: Modulation of sediment transport and storage, with implications for hillslope evolution

    Science.gov (United States)

    Roberts, A. S.; Furbish, D. J.

    2009-12-01

    Studies of mound development beneath desert shrubs by rainsplash transport have focused on the physics of rainsplash transport, as well as on mound characteristics. However, there has been no attempt to examine the relationship between the life cycles of desert shrub populations, sediment storage, sediment transport rates, and ultimately hillslope evolution. Our work examines the timescales over which the presence of a shrub community on a desert hillslope reduces rates of sediment transport and modulates the local divergence of the sediment flux, thereby influencing the rate of hillslope evolution. Mounds develop beneath shrubs as a result of preferential movement of sediment from areas not covered by canopy to areas beneath shrub canopies, where grains are protected from raindrop impacts. The sediment flux immediately downslope of a shrub is reduced as a mound develops. Conversely, removal of canopy cover (i.e. shrub mortality) results in a local increase in sediment flux immediately downslope of a shrub as mound material becomes exposed to rainsplash transport. A hillslope supporting a desert shrub community and mound development experiences an overall lowering of downslope transport rates compared to an unvegetated desert hillslope. Here we develop a numerically-based model for desert hillslopes, supported by field observations of rainsplash mounds in the Cibola National Forest, New Mexico, to investigate how sediment that is stored and released in conjunction with a dynamic shrub population affects desert hillslope evolution. Modeling suggest that it can take on the order of a century for sediment in a mound to be released downslope by rainsplash processes following the death of a shrub. Even as local sediment transport rates increase and decrease in proximity to shrub mounds throughout the life cycle of an individual shrub, sediment transport rates at the hillslope scale are likely to be reduced for as long as the shrub community remains viable. Our work

  14. Early Pleistocene short-term intermediate water mass variability influences Carbonate Mound development in the NE Atlantic (IODP Site 1317)

    Science.gov (United States)

    Raddatz, J.; Rüggeberg, A.; Margreth, S.; Liebetrau, V.; Dullo, W.; Eisenhauer, A.; Iodp Expedition 307 Scientific Party

    2010-12-01

    The Integrated Ocean Drilling Program (IODP) Exp. 307 drilled the 155 m high Challenger Mound in the Porcupine Seabight (SW off Ireland) in order to investigate for the first time sediments from the base of a giant carbonate mound. In this study we focus on sediments from the base of Challenger Mound (Porcupine Seabight, SW off Ireland) IODP Site 1317 in high resolution. The mound initiation and start-up phase coincides with the intensification of the Northern Hemisphere Glaciation (INHG) at around 2.6 Ma. Further carbonate mound development seems to be strongly dependent on rapid changes in paleoceanographic and climatic conditions at the Pliocene-Pleistocene boundary, especially characterized and caused by the interaction of intermediate water masses, the Mediterranean Outflow Water (MOW), the Eastern North Atlantic Water (ENAW) and the influence of Southern Component Water (SCW). This study is based on well-established proxies such as δ18O and δ13C of planktonic (Globigerina bulloides) and benthic foraminifera (Fontbotia wuellerstorfi, Discanomalina coronata, Lobatula lobatula, Lobatula antarctica, and Planulina ariminensis) as well as grain size parameters to identify the paleoenvironmental and paleoecological setting favourable for the initial coral colonization on the mound. Stable oxygen and carbon isotope records of benthic foraminiferal species indicate that L. lobatula provides a reliable isotopic signature for paleoenvironmental reconstructions. In particular, δ18O values of L. lobatula indicate initial mound growth started in a glacial mode with moderate excursions in δ18O values. Bottom water temperatures, calculated using standard equations based on δ18O of foraminiferal tests, range between 7 and 11°C, consistent with the known temperature range conducive for cold-water coral growth and development. Bottom currents transporting intermediate water masses of southern origin (Mediterranean, Bay of Biscay) enhanced at 2.6 Ma supporting first coral

  15. Geology and biology of the "Sticky Grounds", shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

    Science.gov (United States)

    Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

    2016-08-01

    Shelf-margin carbonate mounds in water depths of 116-135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the "Sticky Grounds", trend along slope, are 5-15 m in relief with base diameters of 5-30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve ecosystem

  16. Volcanic hazards on the Island of Hawaii

    Science.gov (United States)

    Mullineaux, Donal Ray; Peterson, Donald W.

    1974-01-01

    Volcanic hazards on the Island of Hawaii have been determined to be chiefly products of eruptions: lava flows, falling fragments, gases, and particle-and-gas clouds. Falling fragments and particle-and-gas clouds can be substantial hazards to life, but they are relatively rare. Lava flows are the chief hazard to property; they are frequent and cover broad areas. Rupture, subsidence, earthquakes, and sea waves (tsunamis) caused by eruptions are minor hazards; those same events caused by large-scale crustal movements, however, are major hazards to both life and property. Volcanic hazards are greatest on Mauna Loa and Kilauea, and the risk is highest along the rift zones of those volcanoes. The hazards are progressively less severe on Hualalai, Mauna Kea, and Kohala volcanoes. Some risk from earthquakes extends across the entire island, and the risk from tsunamis is high all along the coast. The island has been divided into geographic zones of different relative risk for each volcanic hazard, and for all those hazards combined. Each zone is assigned a relative risk for that area as a whole; the degree of risk varies within the zones, however, and in some of them the risk decreases gradationally across the entire zone. Moreover, the risk in one zone may be locally as great or greater than that at some points in the zone of next higher overall risk. Nevertheless, the zones can be highly useful for land-use planning. Planning decisions to which the report is particularly applicable include the selection of kinds of structures and kinds of land use that are appropriate for the severity and types of hazards present. For example, construction of buildings that can resist a lava flow is generally not feasible, but it is both feasible and desirable to build structures that can resist falling rock fragments, earthquakes, and tsunamis in areas where risk from those hazards is relatively high. The report can also be used to select sites where overall risk is relatively low, to

  17. Ft-Ir Spectroscopic Analysis of Potsherds Excavated from the First Settlement Layer of Kuriki Mound, Turkey

    Science.gov (United States)

    Bayazit, Murat; Isik, Iskender; Cereci, Sedat; Issi, Ali; Genc, Elif

    The region covering Southeastern Anatolia takes place in upper Mesopotamia, so it has numerous cultural heritages due to its witness to various social movements of different civilizations in ancient times. Kuruki Mound is located on the junction point of Tigris River and Batman Creek, near Oymatas village which is almost 15 km to Batman, Turkey. The mound is dated back to Late Chalcolithic. Archaeological excavations are carried out on two hills named as “Kuriki Mound-1” and “Kuriki Mound-2” in which 4-layer and 2-layer settlements have been revealed, respectively. This region will be left under the water by the reservoir lake of Ilısu Dam when its construction is completed. Thus, characterization of ancient materials such as potsherds, metals and skeleton ruins should be rapidly done. In this study, 12 potsherds excavated from Layer-1 (the first settlement layer after the surface) in Kuriki Mound-2 were investigated by FT-IR spectrometry. Energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) analyses were used as complementary techniques in order to expose chemical and mineralogical/phase contents, respectively. Obtained results showed that the potteries have been produced with calcareous clays and they include moderate amounts of MgO, K2O, Na2O and Fe2O3 in this context. Additionally, high temperature phases have also been detected with XRD analyses in some samples.

  18. A Model Simulation of Pinatubo Volcanic Aerosols in the Stratosphere

    Science.gov (United States)

    Zhao , Jing-xia; Turco, Richard P.; Toon, Owen B.

    1995-01-01

    A one-dimensional, time-dependent model is used to study the chemical, microphysical, and radiative properties of volcanic aerosols produced by the Mount Pinatubo eruption on June 15, 1991. Our model treats gas-phase sulfur photochemistry, gas-to-particle conversion of sulfur, and the microphysics of sulfate aerosols and ash particles under stratospheric conditions. The dilution and diffusion of the volcanic eruption clouds are also accounted for in these conditions. Heteromolecular homogeneous and heterogeneous binary H2SO4/H2O nucleation, acid and water condensational growth, coagulation, and gravitational sedimentation are treated in detail in the model. Simulations suggested that after several weeks, the volcanic cloud was composed mainly of sulfuric acid/water droplets produced in situ from the SO2 emissions. The large amounts of SO2 (around 20 Mt) injected into the stratosphere by the Pinatubo eruption initiated homogeneous nucleation which generated a high concentration of small H2SO4/H2O droplets. These newly formed particles grew rapidly by condensation and coagulation in the first few months and then reach their stabilized sizes with effective radii in a range between 0.3 and 0.5 micron approximately one-half year after the eruption. The predicted volcanic cloud parameters reasonably agree with measurements in term of the vertical distribution and lifetime of the volcanic aerosols, their basic microphysical structures (e.g., size distribution, concentration, mass ratio, and surface area) and radiative properties. The persistent volcanic aerosols can produce significant anomalies in the radiation field, which have important climatic consequences. The large enhancement in aerosol surface area can result in measurable global stratospheric ozone depletion.

  19. Transition of microbiological and sedimentological features associated with the geochemical gradient in a travertine mound in northern Sumatra, Indonesia

    Science.gov (United States)

    Sugihara, Chiya; Yanagawa, Katsunori; Okumura, Tomoyo; Takashima, Chizuru; Harijoko, Agung; Kano, Akihiro

    2016-08-01

    Modern travertines, carbonate deposits in Ca-rich hydrothermal water with high pCO2, often display a changing environment along the water path, with corresponding variability in the microbial communities. We investigated a travertine-bearing hot spring at the Blue Pool in northern Sumatra, Indonesia. The thermal water of 62 °C with high H2S (200 μM) and pCO2 ( 1 atm) developed a travertine mound 70 m wide. The concentrations of the gas components H2S and CO2, decrease immediately after the water is discharged, while the dissolved oxygen, pH, and aragonite saturation increase in the downstream direction. Responding to the geochemical gradient in the water, the surface biofilms change color from white to pink, light-green, dark-green, and brown as the water flows from the vent; this corresponds to microbial communities characterized by chemolithoautotrophs (Halothiobacillaceae), purple sulfur bacteria (Chromatiaceae), Anaerolineaceae, and co-occurrence of green non-sulfur bacteria (Chloroflexales)-Cyanobacteria, and green sulfur bacteria (Chlorobiales), respectively. In an environment with a certain level of H2S (> 1 μM), sulfur digestion and anoxygenic photosynthesis can be more profitable than oxygenic photosynthesis by Cyanobacteria. The precipitated carbonate mineral consists of aragonite and calcite, with the proportion of aragonite increasing downstream due to the larger Mg2 +/Ca2 + ratio in the water or the development of thicker biofilm. Where the biofilm is well developed, the aragonite travertines often exhibit laminated structures that were likely associated with the daily metabolism of these bacteria. The microbiological and sedimentological features at the Blue Pool may be the modern analogs of geomicrobiological products in the early Earth. Biofilm of anoxygenic photosynthetic bacteria had the potential to form ancient stromatolites that existed before the appearance of cyanobacteria.

  20. Excavation and aggregation as organizing factors in de novo construction by mound-building termites.

    Science.gov (United States)

    Green, Ben; Bardunias, Paul; Turner, J Scott; Nagpal, Radhika; Werfel, Justin

    2017-06-14

    Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in which actions that change the environment provide cues that influence future work. Termite construction has long been thought to be organized via a putative 'cement pheromone': a chemical added to deposited soil that stimulates further deposition in the same area, thus creating a positive feedback loop whereby coherent structures are built up. To investigate the detailed mechanisms and behaviours through which termites self-organize the early stages of mound construction, we tracked the motion and behaviour of major workers from two Macrotermes species in experimental arenas. Rather than a construction process focused on accumulation of depositions, as models based on cement pheromone would suggest, our results indicated that the primary organizing mechanisms were based on excavation. Digging activity was focused on a small number of excavation sites, which in turn provided templates for soil deposition. This behaviour was mediated by a mechanism of aggregation, with termites being more likely to join in the work at an excavation site as the number of termites presently working at that site increased. Statistical analyses showed that this aggregation mechanism was a response to active digging, distinct from and unrelated to putative chemical cues that stimulate deposition. Agent-based simulations quantitatively supported the interpretation that the early stage of de novo construction is primarily organized by excavation and aggregation activity rather than by stigmergic deposition. © 2017 The Author(s).

  1. Integrated Geophysical Techniques for Exploring Deep Volcanic Rock Reservoir

    Institute of Scientific and Technical Information of China (English)

    LiuXuejun; UDechun; ZhangChangjiang; RanXuefeng

    2003-01-01

    The Carboniferous and Pre-Carboniferous formations in Ludong, Zhungar basin, contain favorable oil/gas reservoirs. The Carboniferous formations, however, are complex in structure and exhibit lateral variations in lithology. Seismic reflections from Pre-Triassic formations are poor and the volcanic reservoirs are very difficult to identify. The analysis of physical properties concluded that the major targets in this region, i.e., the top of the Jurassic and Carboniferous formations, provide distinct density interfaces. The basic, intermediate and acid volcanic rocks were also different in density,resulting in distinguishable gravity anomalies. The differences in magnetism in this region existed not only between the volcanic rocks and clastic sedimentary rocks but also among volcanic rocks with different compositions. All formations and volcanic rocks of different lithologies presented high and low resistance interbeds, which are characterized by regional trends.The modeling study demonstrated that non-seismic integrated geophysical techniques should be feasible in this region, especiaUy the high-precision gravity/magnetic methods combined with long offset transient electromagnetic sounding.

  2. Alkali and Halogen Chemistry in Volcanic Gases on Io

    CERN Document Server

    Schaefer, L

    2004-01-01

    We use chemical equilibrium calculations to model the speciation of alkalis and halogens in volcanic gases emitted on Io. The calculations cover wide temperature (500-2000 K) and pressure (10^-6 to 10^+1 bars) ranges, which overlap the nominal conditions at Pele (T = 1760 K, P = 0.01 bars). About 230 compounds of 11 elements (O, S, Li, Na, K, Rb, Cs, F, Cl, Br, I) are considered. We predict the major alkali and halogen species in a Pele-like volcanic gas and the major alklai and halogen condensates. We also model disequilibrium chemistry of the alkalis and halogens in the volcanic plume. Based on this work and our prior modeling for Na, K, and Cl in a volcanic plume, we predict the major loss processes for the alkali halide gases are photolysis and/or condensation onto grains. On the basis of elemental abundances and photochemical lifetimes, we recommend searching for gaseous KCl, NaF, LiF, LiCl, RbF, RbCl, CsF, and CsCl around volcanic vents during eruptions. Based on abundance considerations and observation...

  3. Early Carboniferous (Tournasian-early Visean) global paleogeography, Paleostorm tracts, and the distribution of Waulsortian and Waulsortian-like carbonate mud mounds

    Energy Technology Data Exchange (ETDEWEB)

    King, D.T. Jr. (Auburn Univ., AL (USA))

    1990-05-01

    Tournasian-early Visean mud mounds (i.e., Waulsortian and Waulsortian-like mounds) are unlike other carbonate buildups in the stratigraphic record because they lack an identifiable frame-building organism. Waulsortian mounds are comprised mainly of carbonate mud; Waulsortian-like mounds are mud-rich and contain a significant percent of skeletal grains, especially crinoids and bryozoa. This study has revealed that all of the reported Waulsortian and Waulsortian-like mounds developed in low paleolatitudes either on the southern shelf margin of the Laurussian paleocontinent or in the Laurussian interior seaway. Waulsortian and Waulsortian-like mounds are specifically not present in low-latitude regions of other paleocontinents. As Tournasian-early Visean carbonate deposition was widespread in the range of 30{degree}N to 10{degree}S, the very restricted paleogeographic distribution of Waulsortian and Waulsortian-like mound locations suggests a mechanism or set of conditions that effectively limited the distribution of mud mounds. Considering the Tournasian-early Visean distribution of paleocontinents and the principles that govern the movement of modern hurricanes, tropical storms, and winter storms, the tracts of hurricanes, tropical storms, and winter storms probably crossed all main submerged paleocontinental areas except the southern Laurussian shelf margin and the Laurussian interior seaway, the two areas where mud mounds developed. The lack of storm energy in these two large areas of Laurussia provided long-term stability and thus enhanced the growth prospects of the frame-deficient Waulsortian and Waulsortian-like mud mounds. Lack of extensive periodic wave reworking and other storm-induced devastation helps to account for enigmatic features such as general mound symmetry, great size, high depositional relief (as much as 220 m), and side steepness (as steep as 50{degree}).

  4. Scour at the round head of a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Fredsøe, Jørgen; Sumer, B. Mutlu

    1997-01-01

    This study complements the investigation on scour around the head of a breakwater, reported in the companion paper where the case of vertical-wall breakwater was considered, The present study deals with the case of rubble-mound breakwater. Two key mechanisms with regard to the scour processes......-side of the breakwater. The Keulegan-Carpenter number based on the base diameter of the breakwater head appears to be the main governing parameter regarding the streaming-induced scour, while a parameter, namely T-p root gH(s)/h, involving the peak wave period, T-p, the significant wave height, H-s, the water depth, h...

  5. Overtopping on Rubble Mound Breakwaters for Low Steepness Waves in Deep and Depth Limited Conditions

    DEFF Research Database (Denmark)

    Færch Christensen, Nicole; Røge, Mads Sønderstrup; Thomsen, Jonas Bjerg;

    2014-01-01

    In this paper, the investigation of overtopping on rubble mound breakwaters for low steepness waves in both deep and shallow-water conditions are presented. The existing formulae provide quite different results for long waves for both conventional and berm breakwaters. Therefore, new model tests...... with focus on long waves have been performed for both types of breakwaters. The new model tests showed some deviation from the formulae. Therefore, limitations in the use of the present methods and an update for one of the methods are presented....

  6. Why do we not have a Consistent Design Method for Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    of the art and the design tools are not satisfactory compared to those available in other branches of civil engineering such as for example structural engineering. I shall try to explain the difficulties e are facing in breakwater engineering, especially for rubble mound breakwaters, by summarizing some...... probability density functions of the involved parameters supplied with statistical information on the related persistance. The following presentation is not in accordance with this since each parameter is treated separately. This is done of the sake of simplicity and also because it will still serve the main...

  7. Mound Spring Complexes in Central Australia: An Analog for Martian Groundwater Fed Outflow Channels?

    Science.gov (United States)

    Clarke, J. D. A.; Stoker, C.

    2003-01-01

    The arid inland of Australia contains a diversity of landscapes and landscape processes, often of great antiquity, extending back to the Mesozoic and Paleozoic. The potential of this landscape as a source of Mars analogs has, however, been little explored. The few examples studied so far include radiation-tolerant microbes in thermal springs and hematite-silica hydrothermal alteration near Arkaroola in the Finders Ranges, and aeolian landforms at Gurra Gurra water hole the north east of Arkaroola. Further Australian Mars analog studies were provided by the studies of Bourke and Zimbelman of the paleoflood record of the Todd and Hale Rivers in central Australia. To facilitate study of such analogues, Mars Society Australia has embarked on a project to construct a Mars Analog Research Station near Arkaroola. The international scientific community will soon have the opportunity to participate in Mars analog studies in central Australia utilizing this facility. An area of considerable Mars analog potential is the mound spring complexes that occur at the margins of the Great Artesian Basin (GAB) which underlies 22% of the Australian continent and covers 1.7 million km2. The mound springs are formed when ground water flows to a topographic low, and subsurface strata dips up causing a hydrological head at the surface. Minerals precipitated at the spring discharge zone form low mesas or "mounds", the height of which are controlled by the hydrological head. This paper describes the Dalhousie Mound Spring Complex (DMC) in the northern part of South Australia (Figure 1), and its potential as a Mars analog. Hydrogeology: The DMC consists of a cluster of more than 60 active springs formed by natural discharge from the GAB). Total measured discharge from the GAB is 1.74 GL per day, estimated unfocussed natural leakage through the aquaclude is thought be approximately equal to this figure. Some 54 ML per day are currently discharged by the DMC, 3% of the measured total. The

  8. Wave Forces and Overtopping on Crown Walls of Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Pedersen, Jan

    in the coastal laboratory at Aalborg University. Based on analyses of experimental data a design method for assessing the maximum wave forces on the vertical face of the crown wall structures has been developed as well as new and more versatile design equation for the related overtopping discharges...... of rubble mound breakwater crown walls. This background motivated the initialization of the present study on wave imposed forces and wave overtopping on crown wall structures. The two subjects where investigated through an excessive parametric model study involving more than 370 long duration test series...

  9. Los volcanes y los hombres

    OpenAIRE

    García, Carmen

    2007-01-01

    Desde las entrañas de la tierra, los volcanes han creado la atmósfera, el agua de los océanos, y esculpido los relieves del planeta: son, pues, los zahoríes de la vida. Existen volcanes que los hombres explotan o cultivan, y otros sobre los cuales se han construido observatorios en los que se llevan a cabo avanzadas investigaciones científicas.

  10. Volcanic hazards and aviation safety

    Science.gov (United States)

    Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,

    1996-01-01

    An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

  11. Volcanic Zone, New Zealand

    Directory of Open Access Journals (Sweden)

    Graham J. Weir

    2001-01-01

    Full Text Available A conceptual model of the Taupo Volcanic Zone (TVZ is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

  12. Submarine Hydrothermal Sites in Arc Volcanic-Back Arc Environment: Insight from Recent Marine Geophysical Investigations in the Southern Tyrrhenian Sea.

    Science.gov (United States)

    Cocchi, L.; Ligi, M.; Bortoluzzi, G.; Petersen, S.; Plunkett, S.; Muccini, F.; Canese, S.; Caratori Tontini, F.; Carmisciano, C.

    2014-12-01

    Hydrothermal alteration processes involve mineralogical and chemical changes, which are reflected in a major modification of potential field patterns observed over hydrothermal areas. Basalt-hosted hydrothermal sites exhibit characteristic responses with magnetic lows and minima of the gravity field. Near bottom AUV (Autonomous Underwater Vehicle) based potential field surveys have become a very effective technique in deep sea exploration. Here we present results of recent ship-borne and near seafloor magnetic and gravity investigations at deep (Marsili and Palinuro seamounts) and shallow (Panarea, Basiluzzo and Secca del Capo) hydrothermal sites in the Southern Tyrrhenian Sea including multibeam bathymetry, seafloor reflectivity and seismic profiles. At Marsili seamount, a large Fe-Mn-oxyhydroxides-rich chimney field is located at the summit (500 m depth). This site is correlated with pronounced magnetic and gravity lows (0 A/m and 2.0 g/cm3). Deep tow magnetic survey (Cruise MAVA11) revealed strong association between the complicated magnetization pattern and the main volcano-tectonic features of the ridge. Hydrothermal manifestations at Palinuro seamount occur mainly on the western sector within the rim of a caldera structure at depth of 600m. Recent AUV based magnetic surveys (Cruise POS442, 2012 using AUV "Abyss") detailed a magnetization low interpreted to represent the local distribution of subseafloor hydrothermal alteration (potentially massive sulfide deposits), and also mapped previously undiscovered inactive chimney fields. Hydrothermal sites observed at the arc-related volcanic islands (Panarea, Basiluzzo, Eolo and Secca del Capo) are confined to shallow depths (less then 300m) and associated with large ochreaceous mounds, vents and chimney fields such as those observed E of Basiluzzo Island. At this site a recent magnetic survey (Cruise PANA13_ASTREA) combined with Remote Operated Vehicle (ROV) investigations revealed that the submarine geothermal

  13. Ecosystem engineering creates a direct nutritional link between 600-m deep cold-water coral mounds and surface productivity

    Science.gov (United States)

    Soetaert, Karline; Mohn, Christian; Rengstorf, Anna; Grehan, Anthony; van Oevelen, Dick

    2016-10-01

    Cold-water corals (CWCs) form large mounds on the seafloor that are hotspots of biodiversity in the deep sea, but it remains enigmatic how CWCs can thrive in this food-limited environment. Here, we infer from model simulations that the interaction between tidal currents and CWC-formed mounds induces downwelling events of surface water that brings organic matter to 600-m deep CWCs. This positive feedback between CWC growth on carbonate mounds and enhanced food supply is essential for their sustenance in the deep sea and represents an example of ecosystem engineering of unparalleled magnitude. This ’topographically-enhanced carbon pump’ leaks organic matter that settles at greater depths. The ubiquitous presence of biogenic and geological topographies along ocean margins suggests that carbon sequestration through this pump is of global importance. These results indicate that enhanced stratification and lower surface productivity, both expected consequences of climate change, may negatively impact the energy balance of CWCs.

  14. Enigmatic mounds in 'Subglacial Meltwater Corridors' on the Canadian Shield: a record of channelised, subglacial meltwater drainage during Laurentide deglaciation

    Science.gov (United States)

    Haiblen, Anna; Ward, Brent; Normandeau, Philippe; Campbell, Janet

    2017-04-01

    Esker networks have traditionally been invoked to represent the channelised subglacial drainage system in shield terrains. However, eskers are only one landform found within 'subglacial meltwater corridors' (SMCs) on the Canadian Shield. SMCs are tracts where till has been eroded, bedrock is exposed, and glaciofluvial sediments have been deposited. SMCs are regularly spaced, parallel deglacial ice-flow directions, have undulating longitudinal profiles, and cross modern drainage divides. Our lidar- and field-based mapping near Lac de Gras, Northwest Territories, west of the Keewatin Ice Divide (KID), reveals that eskers are not present in the majority of SMCs. Instead, enigmatic mounds are commonly the dominant landform type. Enigmatic mounds typically occur in groups of 20 to 200. They are commonly composed of sandy diamicton that is coarser grained and better sorted than regional till. This diamicton is occasionally draped with well-sorted, stratified glaciofluvial sediments. Some enigmatic mounds have a single highpoint (individual mounds) while others have a complex, irregular form (complex mounds). Individual mounds have an average long-axis length of 43 m and an average height of meltwater- and ice-flow directions differ, mound long-axis orientations typically cluster about meltwater flow directions. We have also observed SMCs and enigmatic mounds in the South Rae region of Northwest Territories, 450 km SE of Lac de Gras. Multiple types of enigmatic mounds are present in this area: some are similar to those near Lac de Gras, some are composed of till, and some are composed of sorted and stratified sediments. SMCs likely formed late during deglaciation because the enigmatic mounds and eskers that they contain do not appear to have been significantly affected by ice flow following their deposition. We suggest that transient, sheet-type subglacial meltwater flow events resulted in erosion and transport of basal till. Meltwater was likely sourced from supraglacial

  15. Paleoseawater density reconstruction and its implication for cold-water coral carbonate mounds in the northeast Atlantic through time

    Science.gov (United States)

    Rüggeberg, Andres; Flögel, Sascha; Dullo, Wolf-Christian; Raddatz, Jacek; Liebetrau, Volker

    2016-03-01

    Carbonate buildups and mounds are impressive biogenic structures throughout Earth history. In the recent NE Atlantic, cold-water coral (CWC) reefs form giant carbonate mounds of up to 300 m of elevation. The expansion of these coral carbonate mounds is paced by climatic changes during the past 2.7 Myr. Environmental control on their development is directly linked to controls on its main constructors, the reef-building CWCs. Seawater density has been identified as one of the main controlling parameter of CWC growth in the NE Atlantic. One possibility is the formation of a pycnocline above the carbonate mounds, which is increasing the hydrodynamic regime, supporting elevated food supply, and possibly facilitating the distribution of coral larvae. The potential to reconstruct past seawater densities from stable oxygen isotopes of benthic foraminifera has been further developed: a regional equation gives reliable results for three different settings, peak interglacials (e.g., Holocene), peak glacials (e.g., Last Glacial Maximum), and intermediate setting (between the two extremes). Seawater densities are reconstructed for two different NE Atlantic CWC carbonate mounds in the Porcupine Seabight indicating that the development of carbonate mounds is predominantly found at a seawater density range between 27.3 and 27.7 kg m-3 (σΘ notation). Comparable to recent conditions, we interpret the reconstructed density range as a pycnocline serving as boundary layer, on which currents develop, carrying nutrition and possibly coral larvae. The close correlation of CWC reef growth with reconstructed seawater densities through the Pleistocene highlights the importance of pycnoclines and intermediate water mass dynamics.

  16. Experimental explanation of the formation mechanism of surface mound-structures by femtosecond laser on polycrystalline Ni{sub 60}Nb{sub 40}

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Edwin; Wang, Meiyu; Lucis, Michael J.; Gogos, George; Shield, Jeffrey E. [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Tsubaki, Alfred; Zuhlke, Craig A.; Bell, Ryan; Anderson, Troy P.; Alexander, Dennis R. [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2016-01-18

    Femtosecond laser surface processing (FLSP) is an emerging technique for creating functionalized surfaces with specialized properties, such as broadband optical absorption or superhydrophobicity/superhydrophilicity. It has been demonstrated in the past that FLSP can be used to form two distinct classes of mound-like, self-organized micro/nanostructures on the surfaces of various metals. Here, the formation mechanisms of below surface growth (BSG) and above surface growth (ASG) mounds on polycrystalline Ni{sub 60}Nb{sub 40} are studied. Cross-sectional imaging of these mounds by focused ion beam milling and subsequent scanning electron microscopy revealed evidence of the unique formation processes for each class of microstructure. BSG-mound formation during FLSP did not alter the microstructure of the base material, indicating preferential valley ablation as the primary formation mechanism. For ASG-mounds, the microstructure at the peaks of the mounds was clearly different from the base material. Transmission electron microscopy revealed that hydrodynamic melting of the surface occurred during FLSP under ASG-mound forming conditions. Thus, there is a clear difference in the formation mechanisms of ASG- and BSG-mounds during FLSP.

  17. Galileo observations of volcanic plumes on Io

    Science.gov (United States)

    Geissler, P.E.; McMillan, M.T.

    2008-01-01

    Io's volcanic plumes erupt in a dazzling variety of sizes, shapes, colors and opacities. In general, the plumes fall into two classes, representing distinct source gas temperatures. Most of the Galileo imaging observations were of the smaller, more numerous Prometheus-type plumes that are produced when hot flows of silicate lava impinge on volatile surface ices of SO2. Few detections were made of the giant, Pele-type plumes that vent high temperature, sulfur-rich gases from the interior of Io; this was partly because of the insensitivity of Galileo's camera to ultraviolet wavelengths. Both gas and dust spout from plumes of each class. Favorably located gas plumes were detected during eclipse, when Io was in Jupiter's shadow. Dense dust columns were imaged in daylight above several Prometheus-type eruptions, reaching heights typically less than 100 km. Comparisons between eclipse observations, sunlit images, and the record of surface changes show that these optically thick dust columns are much smaller in stature than the corresponding gas plumes but are adequate to produce the observed surface deposits. Mie scattering calculations suggest that these conspicuous dust plumes are made up of coarse grained “ash” particles with radii on the order of 100 nm, and total masses on the order of 106 kg per plume. Long exposure images of Thor in sunlight show a faint outer envelope apparently populated by particles small enough to be carried along with the gas flow, perhaps formed by condensation of sulfurous “snowflakes” as suggested by the plasma instrumentation aboard Galileo as it flew through Thor's plume [Frank, L.A., Paterson, W.R., 2002. J. Geophys. Res. (Space Phys.) 107, doi:10.1029/2002JA009240. 31-1]. If so, the total mass of these fine, nearly invisible particles may be comparable to the mass of the gas, and could account for much of Io's rapid resurfacing.

  18. Seafloor classification of the mound and channel provinces of the Porcupine Seabight: an application of the multibeam angular backscatter data

    Science.gov (United States)

    Beyer, Andreas; Chakraborty, Bishwajit; Schenke, Hans Werner

    2007-02-01

    In this study multibeam angular backscatter data acquired in the eastern slope of the Porcupine Seabight are analysed. Processing of the angular backscatter data using the ‘NRGCOR’ software was made for 29 locations comprising different geological provinces like: carbonate mounds, buried mounds, seafloor channels, and inter-channel areas. A detailed methodology is developed to produce a map of angle-invariant (normalized) backscatter data by correcting the local angular backscatter values. The present paper involves detailed processing steps and related technical aspects of the normalization approach. The presented angle-invariant backscatter map possesses 12 dB dynamic range in terms of grey scale. A clear distinction is seen between the mound dominated northern area (Belgica province) and the Gollum channel seafloor at the southern end of the site. Qualitative analyses of the calculated mean backscatter values i.e., grey scale levels, utilizing angle-invariant backscatter data generally indicate backscatter values are highest (lighter grey scale) in the mound areas followed by buried mounds. The backscatter values are lowest in the inter-channel areas (lowest grey scale level). Moderate backscatter values (medium grey level) are observed from the Gollum and Kings channel data, and significant variability within the channel seafloor provinces. The segmentation of the channel seafloor provinces are made based on the computed grey scale levels for further analyses based on the angular backscatter strength. Three major parameters are utilized to classify four different seafloor provinces of the Porcupine Seabight by employing a semi-empirical method to analyse multibeam angular backscatter data. The predicted backscatter response which has been computed at 20° is the highest for the mound areas. The coefficient of variation (CV) of the mean backscatter response is also the highest for the mound areas. Interestingly, the slope value of the buried mound areas are

  19. Biological and geological characteristics of the R1 and R2 coral mounds, Rockall Trough, west of Ireland.

    Science.gov (United States)

    Unnithan, V.; Grehan, A.; van Weering, T.; Olu-Leroy, K.

    2003-04-01

    The carbonate mounds discovered in the mid-1990s on the Irish Continental Margin are unique. It is not only their size (up to 300 m in height and 2-3 km in diameter), distribution (along the margins of the Porcupine Seabight and Rockall Trough), abundance (> 250 individual mounds) but also their association with deep-water coral species that has generated a great deal of interest in the scientific community. During the past 10 years a number of European Union funded projects concentrated their efforts on studying these deep-sea features. However, there is still a great deal to be learnt regarding mound structure, dynamics and genesis. The basic question why and how carbonate mounds are formed is still largely unanswered. The CARACOLE (CARbonate And COLD water Ecosystems) Cruise in August 2001, was an Irish-French-EU inter-disciplinary co-operation program with participation of ACES, ECOMOUND and GEOMOUND related scientists from Germany, The Netherlands and Belgium to study carbonate mounds and deep-coral reefs in the Porcupine Seabight and Rockall Trough, west of Ireland. The IFREMER led cruise aboard the French Research Vessel Atalante deployed the 'state of the art' remotely operated vehicle, Victor 6000 at a total of 5 mound locations selected on the basis of previous extensive seismic, acoustic and bottom sampling studies, mainly carried out by RV 'Pelagia' of the Royal NIOZ. High-resolution geo-referenced video and digital still photography was used for detailed observation and mapping. This poster presents preliminary results and work in progress from the R1 and R2 Rockall Trough mound sites based on video and bathymetric analysis carried out by the authors in March 2002 at IFREMER. The focus of the analysis was two fold: 1) Biological, encompassing the identification and mapping of coral habitats and associated species, and 2) geological which includes mapping of the morphology and nature (character) of the seabed. From the observations and analysis

  20. Experimental study of 2D scour and its protection at a rubble-mound breakwater

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Fredsøe, Jørgen

    2000-01-01

    This study deals with the 2D scour at the trunk section of a rubble-mound breakwater. Two breakwater models with slopes of 1:1.2 and 1:1.75 are employed for the experimental study of the scour in a wave flume. 2D scour at a vertical-wall breakwater was also included as a reference case. Tests were...... conducted with both regular waves and irregular waves. It was found that the scour/deposition pattern in front of the rubble-mound breakwater emerges in the form of alternating scour and deposition areas lying parallel to the breakwater, similar to the case of the vertical-wall breakwater. The maximum scour...... depth, however, was found to be smaller in the present case than that of the vertical-wall breakwater case. In the case of the irregular waves, the scour depth at the breakwater decreases with respect to that experienced in the case of the regular waves. Countermeasures for toe protection were also...

  1. Composting of cow dung and crop residues using termite mounds as bulking agent.

    Science.gov (United States)

    Karak, Tanmoy; Sonar, Indira; Paul, Ranjit K; Das, Sampa; Boruah, R K; Dutta, Amrit K; Das, Dilip K

    2014-10-01

    The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg(-1) respectively with a bulk density of 0.85 g cm(-3). Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The Topos of the Mound in Samuel Beckett’s Writing

    Directory of Open Access Journals (Sweden)

    Habibi Reza

    2014-01-01

    Full Text Available This essay aims to bring to the fore the varied and broad valences of the ‘mound’ in Beckett’s oeuvre. In my reading, the mound functions as a profuse, multi-purpose symbol, that coalesces into a variety of topoi indicative of Mother Earth, that figure in the thighs, the nipples, the pubis/pubic area and bones, ruins, ants, birth, fetus, and elemental maternal death. I embarked upon the present study before the commencement of the Beckett Digital Manuscript Project, a collaborative project between the Centre for Manuscript Genetics at the University of Antwerp, the Beckett International Foundation, the University of Reading and Harry Ransom Humanities Research Center, the University of Texas at Austin. Valorising the author’s editing, additions, notes and comments provided by the upcoming digitalized manuscripts of Beckett in 2014 and 2015, I expect to contribute to the work in progress, and to the corpus of Beckett studies in general, especially those approaching his bilingual works. It is my contention that the frequency of certain terms, the diagrams that Beckett included in some of his letters (as is the case of the mound in Happy Days, shed significant light on the nature of his symbolism.

  3. Focused risk assessment: Mound Plant, Miami-Erie Canal Operable Unit 4

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, D.R.; Dunning, D.F.

    1994-09-29

    In 1969, an underground waste line at Mound Plant ruptured and released plutonium-238 in a dilute nitric acid solution to the surrounding soils. Most of the acid was neutralized by the native soils. The plutonium, which in a neutral solution is tightly sorbed onto clay particles, remained within the spill area. During remediation, a severe storm eroded some of the contaminated soil. Fine grained plutonium-contaminated clay particles were carried away through the natural drainage courses to the remnants of the Miami-Erie Canal adjacent to Mound Plant, and then into the Great Miami River. This focused risk assessment considers exposure pathways relevant to site conditions, including incidental ingestion of contaminated soils, ingestion of drinking water and fish, and inhalation of resuspended soils and sediments. For each potential exposure pathway, a simplified conceptual model and exposure scenarios have been used to develop conservative estimates of potential radiation dose equivalents and health risks. The conservatism of the dose and risk estimates provides a substantive margin of safety in assuring that the public health is protected.

  4. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-chen; Lin, Shih-guei; Suganuma, Katsuaki

    2016-01-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings. PMID:27703220

  5. Supercomputer modeling of volcanic eruption dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

    1995-06-01

    Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.

  6. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-Kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-Chen; Lin, Shih-Guei; Suganuma, Katsuaki

    2016-10-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings.

  7. 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...... Pleistocene times. These basalts mark the end of a period of shallow subduction of the Nazca slab beneath the Payenia province and volcanism in the Nevado volcanic field apparently followed the downwarping slab in a north-northwest direction ending in the Northern Segment. The northern Payenia basalts...... the literature. The Nevado basalts have been modelled by 4-10 % melting of a primitive mantle added 1-5 % upper continental crust. In the southern Payenia province, intraplate basalts dominate. The samples from the Payún Matrú and Río Colorado volcanic fields are apparently unaffected by the subducting slab...

  8. New ground-based lidar enables volcanic CO2 flux measurements.

    Science.gov (United States)

    Aiuppa, Alessandro; Fiorani, Luca; Santoro, Simone; Parracino, Stefano; Nuvoli, Marcello; Chiodini, Giovanni; Minopoli, Carmine; Tamburello, Giancarlo

    2015-09-01

    There have been substantial advances in the ability to monitor the activity of hazardous volcanoes in recent decades. However, obtaining early warning of eruptions remains challenging, because the patterns and consequences of volcanic unrests are both complex and nonlinear. Measuring volcanic gases has long been a key aspect of volcano monitoring since these mobile fluids should reach the surface long before the magma. There has been considerable progress in methods for remote and in-situ gas sensing, but measuring the flux of volcanic CO2-the most reliable gas precursor to an eruption-has remained a challenge. Here we report on the first direct quantitative measurements of the volcanic CO2 flux using a newly designed differential absorption lidar (DIAL), which were performed at the restless Campi Flegrei volcano. We show that DIAL makes it possible to remotely obtain volcanic CO2 flux time series with a high temporal resolution (tens of minutes) and accuracy (volcanic CO2 represents a major step forward in volcano monitoring, and will contribute improved volcanic CO2 flux inventories. Our results also demonstrate the unusually strong degassing behavior of Campi Flegrei fumaroles in the current ongoing state of unrest.

  9. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  10. Climatic impact of volcanic eruptions

    Science.gov (United States)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  11. Remote monitoring of volcanic gases using passive Fourier transform spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Love, S.P.; Goff, F.; Counce, D.; Schmidt, S.C. [Los Alamos National Lab., NM (United States); Siebe, C.; Delgado, H. [Univ. Nactional Autonoma de Mexico, Coyoacan (Mexico)

    1999-06-01

    Volcanic gases provide important insights on the internal workings of volcanoes and changes in their composition and total flux can warn of impending changes in a volcano`s eruptive state. In addition, volcanoes are important contributors to the earth`s atmosphere, and understanding this volcanic contribution is crucial for unraveling the effect of anthropogenic gases on the global climate. Studies of volcanic gases have long relied upon direct in situ sampling, which requires volcanologists to work on-site within a volcanic crater. In recent years, spectroscopic techniques have increasingly been employed to obtain information on volcanic gases from greater distances and thus at reduced risk. These techniques have included UV correlation spectroscopy (Cospec) for SO{sub 2} monitoring, the most widely-used technique, and infrared spectroscopy in a variety of configurations, both open- and closed-path. Francis et al. have demonstrated good results using the sun as the IR source. This solar occultation technique is quite useful, but puts rather strong restrictions on the location of instrument and is thus best suited to more accessible volcanoes. In order to maximize the flexibility and range of FTIR measurements at volcanoes, work over the last few years has emphasized techniques which utilize the strong radiance contrast between the volcanic gas plume and the sky. The authors have successfully employed these techniques at several volcanoes, including the White Island and Ruapehu volcanoes in New Zealand, the Kilauea volcano on Hawaii, and Mt. Etna in Italy. But Popocatepetl (5452 m), the recently re-awakened volcano 70 km southeast of downtown Mexico City, has provided perhaps the best examples to date of the usefulness of these techniques.

  12. Imaging trace gases in volcanic plumes with Fabry Perot Interferometers

    Science.gov (United States)

    Kuhn, Jonas; Platt, Ulrich; Bobrowski, Nicole; Lübcke, Peter; Wagner, Thomas

    2017-04-01

    Within the last decades, progress in remote sensing of atmospheric trace gases revealed many important insights into physical and chemical processes in volcanic plumes. In particular, their evolution could be studied in more detail than by traditional in-situ techniques. A major limitation of standard techniques for volcanic trace gas remote sensing (e.g. Differential Optical Absorption Spectroscopy, DOAS) is the constraint of the measurement to a single viewing direction since they use dispersive spectroscopy with a high spectral resolution. Imaging DOAS-type approaches can overcome this limitation, but become very time consuming (of the order of minutes to record a single image) and often cannot match the timescales of the processes of interest for volcanic gas measurements (occurring at the order of seconds). Spatially resolved imaging observations with high time resolution for volcanic sulfur dioxide (SO2) emissions became possible with the introduction of the SO2-Camera. Reducing the spectral resolution to two spectral channels (using interference filters) that are matched to the SO2 absorption spectrum, the SO2-Camera is able to record full frame SO2 slant column density distributions at a temporal resolution on the order of BrO) and chlorine dioxide (OClO) both yield absorption features that allow their detection with the FPI correlation technique. From BrO and OClO data, ClO levels in the plume could be calculated. We present an outline of applications of the FPI technique to imaging a series of trace gases in volcanic plumes. Sample calculations on the sensitivity and selectivity of the technique, first proof of concept studies and proposals for technical implementations are presented.

  13. Aurorae and Volcanic Eruptions

    Science.gov (United States)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  14. Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

    Institute of Scientific and Technical Information of China (English)

    WANG Pu-Jun; HOU Qi-jun; CHENG Ri-hui; LI Quan-lin; GUO Zhen-hua; HUANG Yu-long

    2004-01-01

    Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions.Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ12C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb,suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.

  15. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  16. Volcanic eruptions and solar activity

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  17. Models of volcanic eruption hazards

    Energy Technology Data Exchange (ETDEWEB)

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  18. Marketing research for EE G Mound Applied Technologies' heat treatment process of high strength materials

    Energy Technology Data Exchange (ETDEWEB)

    Shackson, R.H.

    1991-10-09

    This report summarizes research conducted by ITI to evaluate the commercialization potential of EG G Mound Applied Technologies' heat treatment process of high strength materials. The remainder of the report describes the nature of demand for maraging steel, extent of demand, competitors, environmental trends, technology life cycle, industry structure, and conclusion. (JL)

  19. Hydrodynamic conditions in a cold-water coral mound area on the Renard Ridge, southern Gulf of Cadiz

    NARCIS (Netherlands)

    Mienis, F.; De Stigter, H.C.; de Haas, H.; van der Land, C.; van Weering, T.C.E.

    2012-01-01

    Near-bed hydrodynamic conditions obtained by bottom landers on the Renard Ridge are presented complemented with a data set from repeated CTD casts. On the Renard Ridge cold-water coral mounds were discovered in the last 10 years. Unlike cold-water coral habitats known from the Norwegian and Irish ma

  20. Computer aided optimum design of rubble-mound breakwater cross-sections: manual of the RUMBA computer package, release 1

    NARCIS (Netherlands)

    De Haan, W.

    1989-01-01

    The computation of the optimum rubble-mound breakwater crosssection is executed on a micro-computer. The RUMBA computer package consists of two main parts: the optimization process is executed by a Turbo Pascal programme, the second part consists of editing functions written in AutoLISP. AutoLISP is

  1. Interactive effects of soil-dwelling ants, ant mounds and simulated grazing on local plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Olff, H.

    2011-01-01

    Interactions between aboveground vertebrate herbivores and subterranean yellow meadow ants (Lasius flavus) can drive plant community patterns in grassland ecosystems. Here, we study the relative importance of the presence of ants (L. flavus) and ant mounds under different simulated grazing regimes

  2. Computer aided optimum design of rubble-mound breakwater cross-sections: manual of the RUMBA computer package, release 1

    NARCIS (Netherlands)

    De Haan, W.

    1989-01-01

    The computation of the optimum rubble-mound breakwater crosssection is executed on a micro-computer. The RUMBA computer package consists of two main parts: the optimization process is executed by a Turbo Pascal programme, the second part consists of editing functions written in AutoLISP. AutoLISP is

  3. Duff mound consumption and cambium injury for centuries-old western larch from prescribed burning in western Montana

    Science.gov (United States)

    Michael G. Harrington

    2012-01-01

    Western larch is one of the most fire-adapted conifers in western North America. Its historical perpetuation depended upon regular fire disturbances, which creates open stand conditions and mineral seedbeds. A stand of 200- to 500-year-old larch in western Montana with deep duff mounds resulting from an unusually long 150-year fire-free period was mechanically thinned...

  4. Hydrodynamic conditions in a cold-water coral mound area on the Renard Ridge, southern Gulf of Cadiz

    NARCIS (Netherlands)

    Mienis, F.; De Stigter, H.C.; de Haas, H.; van der Land, C.; van Weering, T.C.E.

    2012-01-01

    Near-bed hydrodynamic conditions obtained by bottom landers on the Renard Ridge are presented complemented with a data set from repeated CTD casts. On the Renard Ridge cold-water coral mounds were discovered in the last 10 years. Unlike cold-water coral habitats known from the Norwegian and Irish

  5. Hydrodynamic conditions in a cold-water coral mound area on the Renard Ridge, southern Gulf of Cadiz

    NARCIS (Netherlands)

    Mienis, F.; De Stigter, H.C.; de Haas, H.; van der Land, C.; van Weering, T.C.E.

    2012-01-01

    Near-bed hydrodynamic conditions obtained by bottom landers on the Renard Ridge are presented complemented with a data set from repeated CTD casts. On the Renard Ridge cold-water coral mounds were discovered in the last 10 years. Unlike cold-water coral habitats known from the Norwegian and Irish ma

  6. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Sang Kil Park

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls (γν = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  7. Effects of vertical wall and tetrapod weights on wave overtopping in rubble mound breakwaters under irregular wave conditions

    Directory of Open Access Journals (Sweden)

    Park Sang Kil

    2014-12-01

    Full Text Available Rubble mound breakwaters protect the coastal line against severe erosion caused by wave action. This study examined the performance of different sizes and properties (i.e. height of vertical wall and tetrapod size of rubble mound breakwaters on reducing the overtopping discharge. The physical model used in this study was derived based on an actual rubble mound in Busan Yacht Harbor. This research attempts to fill the gap in practical knowledge on the combined effect of the armor roughness and vertical wall on wave overtopping in rubble mound breakwaters. The main governing parameters used in this study were the vertical wall height, variation of the tetrapod weights, initial water level elevation, and the volume of overtopping under constant wave properties. The experimental results showed that the roughness factor differed according to the tetrapod size. Furthermore, the overtopping discharge with no vertical wall was similar to that with relatively short vertical walls ( 1 γv = 1. Therefore, the experimental results highlight the importance of the height of the vertical wall in reducing overtopping discharge. Moreover, a large tetrapod size may allow coastal engineers to choose a shorter vertical wall to save cost, while obtaining better performance.

  8. An electric and electromagnetic geophysical approach for subsurface investigation of anthropogenic mounds in an urban environment

    Science.gov (United States)

    Pazzi, Veronica; Tapete, Deodato; Cappuccini, Luca; Fanti, Riccardo

    2016-11-01

    Scientific interest in mounds as geomorphological features that currently represent topographic anomalies in flat urban landscapes mainly lies on the understanding of their origin, either purely natural or anthropogenic. In this second circumstance, another question is whether traces of lost buildings are preserved within the mound subsurface and can be mapped as remnants testifying past settlement. When these landforms have been modified in centuries for civilian use, structural stability is a further element of concern. To address these issues we applied a geophysical approach based on a very low frequency electromagnetic (VLF-EM) technique and two-dimensional electrical resistivity tomography (2D-ERT) and integrated it with well-established surface survey methods within a diagnostic workflow of structural assessment. We demonstrate the practical benefits of this method in the English Cemetery of Florence, Italy, whose mixed nature and history of morphological changes are suggested by archival records. The combination of the two selected geophysical techniques allowed us to overcome the physical obstacles caused by tomb density and to prevent interference from the urban vehicular traffic on the geophysical signals. Eighty-two VLF-EM profiles and five 2D-ERTs were collected to maximise the spatial coverage of the subsurface prospection, while surface indicators of instability (e.g., tomb tilt, location, and direction of ground fractures and wall cracks) were mapped by standard metric survey. High resistive anomalies (> 300 and 400 Ωm) observed in VLF-EM tomographies are attributed to remnants of the ancient perimeter wall that are still buried along the southern side of the mound. While no apparent correlation is found between the causes of tomb and ground movements, the crack pattern map supplements the overall structural assessment. The main outcome is that the northern portion of the retaining wall is classed with the highest hazard rate. The impact of this

  9. Testing of the small sample (new concept) calorimeter received from EG&G Mound Applied Technology

    Energy Technology Data Exchange (ETDEWEB)

    Cech, R.; Craft, M.; Fultz, R. [and others

    1998-12-31

    The Small Sample calorimeter, also known as the New Concepts calorimeter, has undergone testing in the transfer of the calorimeter operations to Los Alamos National Laboratory from EG&G Mound Applied Technology (Mound), Miamisburg, Ohio, in September 1996. The design of the calorimeter incorporated several new concepts, thus the name New Concepts. The normal water bath was replaced with a small self-contained bath and control that used a thermal electric cooling/heating device to supply the control for the bath temperature. This change replaces the large refrigeration unit that has been used in the past, thus reducing the weight and the power required to operate the system. The design was done to allow the complete calorimeter system to be contained in a single electronics rack. With the new electronics package, this change would allow the unit to use a short electronics rack with a laptop computer and make the complete system transportable. By reducing the amount of water in the bath, the control and size of the bath could also be reduced. By making the bath self-contained and sealed, there would be no need to replace water or supply de-ionized water for the system. This change would remove some of the concerns about using a water bath in certain situations. The water would be about 5 gal. or less depending on the size of the calorimeter. The present system is a 5 in. diameter sample chamber system which can accept most older material now in storage. It will not handle the new 3013 size container as built but could be easily designed for that size. There is also a new sensor design that takes less wire and can eliminate the constant current source used in past Mound calorimeter designs. With the new digital voltmeters, the complete system could be run from a single meter with the ability to monitor bath and room as well as the calorimeter operating voltages for electrical heater runs. A few problems, though minor, need to be corrected to make the system available.

  10. Recurrence models of volcanic events: Applications to volcanic risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.M. [Los Alamos National Lab., Las Vegas, NV (United States); Picard, R.; Valentine, G. [Los Alamos National Lab., NM (United States); Perry, F.V. [New Mexico Univ., Albuquerque, NM (United States)

    1992-03-01

    An assessment of the risk of future volcanism has been conducted for isolation of high-level radioactive waste at the potential Yucca Mountain site in southern Nevada. Risk used in this context refers to a combined assessment of the probability and consequences of future volcanic activity. Past studies established bounds on the probability of magmatic disruption of a repository. These bounds were revised as additional data were gathered from site characterization studies. The probability of direct intersection of a potential repository located in an eight km{sup 2} area of Yucca Mountain by ascending basalt magma was bounded by the range of 10{sup {minus}8} to 10{sup {minus}10} yr{sup {minus}1 2}. The consequences of magmatic disruption of a repository were estimated in previous studies to be limited. The exact releases from such an event are dependent on the strike of an intruding basalt dike relative to the repository geometry, the timing of the basaltic event relative to the age of the radioactive waste and the mechanisms of release and dispersal of the waste radionuclides in the accessible environment. The combined low probability of repository disruption and the limited releases associated with this event established the basis for the judgement that the risk of future volcanism was relatively low. It was reasoned that that risk of future volcanism was not likely to result in disqualification of the potential Yucca Mountain site.

  11. Controls on volcanism at intraplate basaltic volcanic fields

    Science.gov (United States)

    van den Hove, Jackson C.; Van Otterloo, Jozua; Betts, Peter G.; Ailleres, Laurent; Cas, Ray A. F.

    2017-02-01

    A broad range of controlling mechanisms is described for intraplate basaltic volcanic fields (IBVFs) in the literature. These correspond with those relating to shallow tectonic processes and to deep mantle plumes. Accurate measurement of the physical parameters of intraplate volcanism is fundamental to gain an understanding of the controlling factors that influence the scale and location of a specific IBVF. Detailed volume and geochronology data are required for this; however, these are not available for many IBVFs. In this study the primary controls on magma genesis and transportation are established for the Pliocene-Recent Newer Volcanics Province (NVP) of south-eastern Australia as a case-study for one of such IBVF. The NVP is a large and spatio-temporally complex IBVF that has been described as either being related to a deep mantle plume, or upper mantle and crustal processes. We use innovative high resolution aeromagnetic and 3D modelling analysis, constrained by well-log data, to calculate its dimensions, volume and long-term eruptive flux. Our estimates suggest volcanic deposits cover an area of 23,100 ± 530 km2 and have a preserved dense rock equivalent of erupted volcanics of least 680 km3, and may have been as large as 900 km3. The long-term mean eruptive flux of the NVP is estimated between 0.15 and 0.20 km3/ka, which is relatively high compared with other IBVFs. Our comparison with other IBVFs shows eruptive fluxes vary up to two orders of magnitude within individual fields. Most examples where a range of eruptive flux is available for an IBVF show a correlation between eruptive flux and the rate of local tectonic processes, suggesting tectonic control. Limited age dating of the NVP has been used to suggest there were pulses in its eruptive flux, which are not resolvable using current data. These changes in eruptive flux are not directly relatable to the rate of any interpreted tectonic driver such as edge-driven convection. However, the NVP and other

  12. Application Of Recent (2008-2013) Lunar Probe Instrumentation To The Exploration For Precambrian Protolife In Volcanic Vents

    Science.gov (United States)

    Green, Jack

    2009-12-01

    Selected recent and future lunar probes have instruments suitable for the exploration of Precambrian protolife. Fumaroles contain the ingredients for protolife. With available energy including flow charging and charge separation, amino acids and related compounds could evolve into ATP. Fischer-Tropsch reactions in hydrothermal clay could create lipid micelles as reaction chambers. Fumarolic polyphosphates and tungsten catalysts could contribute to precambrian protolife evolution . The floors of Alphonsus and Lavoisier M exhibit dark mounds which could be buried fumaroles at fracture intersections. Chang'e-1 could define regolith thickness at these mounds with microwave radiometry. The MoonLITE penetrometer could likely identify hydrothermal products in these mounds using X-ray fluorescence spectrometry. Regarding polar craters which may host volcanic ices, intermittent illumination of selected crater floors warmed to 220 K may create a transient tenuous atmosphere of COS, H2S, CO2, CO, HCl and CH4 which could be analyzed by near infrared spectrometry (NIMS) of SELENE or Chandrayaan-1. Prior to the 2009 impact of a polar crater by LCROSS (of the LRO mission), the Soviet LEND mission may detect water using epithermal neutrons. The impact plume proposed in the LCROSS mission at a polar crater could be analyzed by NIMS for fumarolic fluids similar the the NIMS analyses of Callisto and Ganymede moons of Jupiter. The possible identification of cyanogen in the LCROSS impact plume would support the CN2 spectrogram at Aristarchus by Kozyrev in 1969. In the Aristarchus region, lunar dawn during periods of maximum orbital flexing may accentuate release of Rn, Ar and protolife gases. These gases could possibly by identified by the Chang'e-1 gamma/x ray spectrometer, NIMS and the neutral mass spectrometer of the LADEE mission. Microwave spectrometry and radar on the LEO mission as well as LROC (LRO mission) could also be directed at verified lunar transient sites.

  13. Ecological feedbacks. Termite mounds can increase the robustness of dryland ecosystems to climatic change.

    Science.gov (United States)

    Bonachela, Juan A; Pringle, Robert M; Sheffer, Efrat; Coverdale, Tyler C; Guyton, Jennifer A; Caylor, Kelly K; Levin, Simon A; Tarnita, Corina E

    2015-02-06

    Self-organized spatial vegetation patterning is widespread and has been described using models of scale-dependent feedback between plants and water on homogeneous substrates. As rainfall decreases, these models yield a characteristic sequence of patterns with increasingly sparse vegetation, followed by sudden collapse to desert. Thus, the final, spot-like pattern may provide early warning for such catastrophic shifts. In many arid ecosystems, however, termite nests impart substrate heterogeneity by altering soil properties, thereby enhancing plant growth. We show that termite-induced heterogeneity interacts with scale-dependent feedbacks to produce vegetation patterns at different spatial grains. Although the coarse-grained patterning resembles that created by scale-dependent feedback alone, it does not indicate imminent desertification. Rather, mound-field landscapes are more robust to aridity, suggesting that termites may help stabilize ecosystems under global change. Copyright © 2015, American Association for the Advancement of Science.

  14. Topological defect launches 3D mound in the active nematic sheet of neural progenitors

    CERN Document Server

    Kawaguchi, Kyogo; Sano, Masaki

    2016-01-01

    Cultured stem cells have become a standard platform not only for regenerative medicine and developmental biology but also for biophysical studies. Yet, the characterization of cultured stem cells at the level of morphology and macroscopic patterns resulting from cell-to-cell interactions remain largely qualitative, even though they are the simplest features observed in everyday experiments. Here we report that neural progenitor cells (NPCs), which are multipotent stem cells that give rise to cells in the central nervous system, rapidly glide and stochastically reverse its velocity while locally aligning with neighboring cells, thus showing features of an active nematic system. Within the two-dimensional nematic pattern, we find interspaced topological defects with +1/2 and -1/2 charges. Remarkably, we identified rapid cell accumulation leading to three-dimensional mounds at the +1/2 topological defects. Single-cell level imaging around the defects allowed quantification of the evolving cell density, clarifyin...

  15. Characterization of magnetic material in the mound-building termite Macrotermes gilvus in Southeast Asia

    Energy Technology Data Exchange (ETDEWEB)

    Esa, Mohammad Faris Mohammad; Hassan, Ibrahim Haji [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia); Rahim, Faszly; Hanifah, Sharina Abu [School of Environmental Scieces and Natural Resources Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia)

    2015-09-25

    Magnetic material such as magnetite are known as particles that respond to external magnetic field with their ferromagnetic properties as they are believed contribute to in responding to the geomagnetic field. These particles are used by terrestrial animals such as termites for navigation and orientation. Since our earth react as giant magnetic bar, the magnitude of this magnetic field present by intensity and direction (inclination and direction). The magnetic properties and presence of magnetite in termites Macrotermes gilvus, common mound-building termite were tested. M. gilvus termites was tested with a Vibrating Sample Magnetometer VSM to determine the magnetic properties of specimen. The crushed body sample was characterized with X-Ray Diffraction XRD to show the existent of magnetic material (magnetite) in the specimens. Results from VSM indicate that M. gilvus has diamagnetism properties. The characterization by XRD shows the existent of magnetic material in our specimen in low concentration.

  16. Flow and Turbulence at Rubble-Mound Breakwater Armor Layers under Solitary Wave

    DEFF Research Database (Denmark)

    Jensen, Bjarne; Christensen, Erik Damgaard; Sumer, B. Mutlu

    2015-01-01

    This paper presents the results of an experimental investigation of the flow and turbulence at the armor layer of rubble-mound breakwaters during wave action. The study focused on the details of the flow and turbulence in the armor layer and on the effect of the porous core on flow and stability....... To isolate the processes involved with the flow in the porous core, experiments were conducted with increasing complexity. Specifically, three parallel experiments were performed including (1) an impermeable smooth breakwater slope, (2) an impermeable breakwater slope with large roughness elements added...... to the breakwater, and (3) a porous breakwater where the porous core was added below the breakwater front. One breakwater slope of 1:1.5 was applied. In this paper the focus is on the details of a single sequence of wave approach, run-up, and rundown. To isolate this sequence the experiments were performed applying...

  17. An overview of plutonium-238 decontamination and decommissioning (D and D) projects at Mound

    Energy Technology Data Exchange (ETDEWEB)

    Bond, W.H.; Davis, W.P.; Draper, D.G.; Geichman, J.R.; Harris, J.C.; Jaeger, R.R.; Sohn, R.L.

    1987-01-01

    Mound is currently decontaminating for restricted reuse and/or decommissioning for conditional release four major plutonium-238 contaminated facilities that contained 1700 linear feet of gloveboxes and associated equipment and services. Several thousand linear feet of external underground piping, associated tanks, and contaminated soil are being removed. Two of the facilities contain ongoing operations and will be reused for both radioactive and nonradioactive programs. Two others will be completely demolished and the land area will become available for future DOE building sites. An overview of the successful techniques and equipment used in the decontamination and decommissioning of individual pieces of equipment, gloveboxes, services, laboratories, sections of buildings, entire buildings, and external underground piping, tanks, and soil in a highly populated residential area is described and pictorially presented.

  18. The hill forts and castle mounds in Lithuania: interaction between geodiversity and human-shaped landscape

    Science.gov (United States)

    Skridlaite, Grazina; Guobyte, Rimante; Satkunas, Jonas

    2015-04-01

    Lithuania is famous for its abundant, picturesque hill forts and castle mounds of natural origin. In Lithuania as well as in whole Europe the fortified hills were used as the society dwelling place since the beginning of the Late Bronze Age. Their importance increased when Livonian and Teutonic Orders directed a series of military campaigns against Lithuania with the aim of expansion of Christianity in the region at the end of 1st millennium AD, and they were intensively used till the beginning of the 15th c. when most of them were burned down during fights with the Orders or just abandoned due to the changing political and economical situation. What types of the geodiversity were used for fortified dwellings? The choice in a particular area depended on a variety of geomorphology left behind the retreating ice sheets. High spots dominating their surroundings were of prime interest. In E and SE Lithuania, the Baltic Upland hills marking the eastern margin of the last Weichselian glacier hosted numerous fortified settlements from the end of 2nd millennium BC to the Medieval Ages (Narkunai, Velikuskes etc). In W Lithuania, plateau-like hills of the insular Samogitian Upland had been repeatedly fortified from the beginning of 1st millennium AD to the 14th century (Satrija, Medvegalis etc). Chains of hill forts and castle mounds feature the slopes of glaciofluvial valleys of Nemunas, Neris and other rivers where the slopes were dissected by affluent rivulets and ravines and transformed into isolated, well protected hills (Kernave, Punia, Veliuona etc). Peninsulas and headlands formed by the erosion of fluvial and lacustrine deposits were used in the lowlands, e.g. in central and N Lithuania (Paberze, Mezotne etc). How much the landscape was modified for defense purposes? Long-term erosion and overgrowing vegetation damaged the former fortified sites, however some remains and the archeological excavations allowed their reconstruction. The fortified Bronze Age settlements

  19. Termination of the Special Metallurgical (SM) Building at Mound Laboratory: a final report

    Energy Technology Data Exchange (ETDEWEB)

    Harris, W.R.; Kokenge, B.R.; Marsh, G.C.

    1976-12-22

    The report describes and highlights the more important factors associated with the termination of the Special Metallurgical (SM) Building at Mound Laboratory. As a result, a written record of the more important techniques and procedures is now available for reference by others involved in similar termination efforts. Included in this report is a description of the organizational units that were used in this effort along with a description of their responsibilities. A general description of the SM Building and a discussion of the more relevant procedures and equipment that were used are also presented. In addition, pertinent Health Physics information, such as personnel exposure, final wipe levels in the terminated facility, and assays of the structure, are provided. Based on the experience gained from this project, recommendations were made regarding the design of future radioactive material handling facilities so that when they are ultimately terminated the effort can be accomplished more efficiently.

  20. Short-billed dowitchers crowd a grassy mound in the waters around KSC

    Science.gov (United States)

    1999-01-01

    A flock of short-billed dowitchers crowd onto a grassy mound in the shallow waters of the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The dowitchers range from southern Alaska to eastern Canada, and they winter from the southern United States to central South America. They often frequent coastal flats during migrations. The 92,000- acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  1. Role of volcanic forcing on future global carbon cycle

    Directory of Open Access Journals (Sweden)

    J. F. Tjiputra

    2011-06-01

    Full Text Available Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with a business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller eruptions similar to Pinatubo in amplitude, but set to occur frequently, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before it returns to the warming trend. Therefore, the climate change is approximately delayed by several decades, and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. Our climate-carbon feedback analysis shows that future volcanic eruptions induce positive feedbacks (i.e., more carbon sink on both the terrestrial and oceanic carbon cycle. The feedback signal on the ocean is consistently smaller than the terrestrial counterpart and the feedback strength is proportionally related to the frequency of the volcanic eruption events. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45 % increase in accumulated carbon uptake over land. The increased solubility of CO2 gas in seawater associated with cooler SST is offset by a reduced CO2 partial pressure gradient between the ocean and the atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even

  2. Role of volcanic forcing on future global carbon cycle

    Science.gov (United States)

    Tjiputra, J. F.; Otterå, O. H.

    2011-06-01

    Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with a business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller eruptions similar to Pinatubo in amplitude, but set to occur frequently, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before it returns to the warming trend. Therefore, the climate change is approximately delayed by several decades, and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. Our climate-carbon feedback analysis shows that future volcanic eruptions induce positive feedbacks (i.e., more carbon sink) on both the terrestrial and oceanic carbon cycle. The feedback signal on the ocean is consistently smaller than the terrestrial counterpart and the feedback strength is proportionally related to the frequency of the volcanic eruption events. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45 % increase in accumulated carbon uptake over land. The increased solubility of CO2 gas in seawater associated with cooler SST is offset by a reduced CO2 partial pressure gradient between the ocean and the atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even in the relatively extreme scenario where

  3. A quantitative model for volcanic hazard assessment

    OpenAIRE

    W. Marzocchi; Sandri, L.; Furlan, C

    2006-01-01

    Volcanic hazard assessment is a basic ingredient for risk-based decision-making in land-use planning and emergency management. Volcanic hazard is defined as the probability of any particular area being affected by a destructive volcanic event within a given period of time (Fournier d’Albe 1979). The probabilistic nature of such an important issue derives from the fact that volcanic activity is a complex process, characterized by several and usually unknown degrees o...

  4. Age constraints on the origin and growth history of a deep-water coral mound in the northeast Atlantic drilled during Integrated Ocean Drilling Program Expedition 307

    Science.gov (United States)

    Kano, Akihiro; Ferdelman, Timothy G.; Williams, Trevor; Henriet, Jean-Pierre; Ishikawa, Tsuyoshi; Kawagoe, Noriko; Takashima, Chiduru; Kakizaki, Yoshihiro; Abe, Kohei; Sakai, Saburo; Browning, Emily L.; Li, Xianghui; Ocean Drilling Program Expedition 307 Scientists

    2007-11-01

    Sr isotope stratigraphy provides a new age model for the first complete section drilled through a deep-water coral mound. The 155-m-long section from Challenger Mound in the Porcupine Sea-bight, southwest of Ireland, is on Miocene siliciclastics and consists entirely of sediments bearing well-preserved cold-water coral Lophelia pertusa. The 87Sr/86Sr values of 28 coral specimens from the mound show an upward-increasing trend, correspond to ages from 2.6 to 0.5 Ma, and identify a significant hiatus from ca. 1.7 to 1.0 Ma at 23.6 m below seafloor. The age of the basal mound sediments coincides with the intensification of Northern Hemisphere glaciations that set up the modern stratification of the northeast Atlantic and enabled coral growth. Mound growth persisted throughout glacial-interglacial fluctuations, reached a maximum rate (24 cm/k.y.) ca. 2.0 Ma, and ceased at 1.7 Ma. Unlike other buried mounds in Porcupine Seabight, Challenger Mound was only partly covered during its growth interruption, and growth restarted ca. 1.0 Ma.

  5. Seismic Tremors and Magma Wagging During Explosive Volcanism

    Science.gov (United States)

    Jellinek, M.; Bercovici, D.

    2010-12-01

    Volcanic tremor is a ubiquitous feature of explosive eruptions. This ground oscillation persists for minutes to weeks and is characterized by a remarkably narrow band of frequencies (i.e., ~0.5 - 7 Hz). Prior to major eruptions, tremor can occur in concert with ground deformation probably related to a buildup of magmatic gas. Volcanic tremor is, thus, of particular value for eruption forecasting. Most models for volcanic tremor rely on specific properties of the geometry, structure and constitution of volcanic conduits as well as the gas content of the erupting magma. Because neither the initial structure nor the evolution of the magma-conduit system will be the same from one volcano to the next, it is surprising that tremor characteristics are so consistent among different volcanoes. Indeed, this universality of tremor properties remains a major enigma. Here we employ the contemporary view that silicic magma rises in the conduit as a columnar plug surrounded by a highly vesicular annulus of sheared bubbles. We demonstrate that, for most geologically relevant conditions, the magma column will oscillate or "wag" against the restoring "gas-spring" force of the annulus at observed tremor frequencies. In contrast to previous models, the magma wagging oscillation is relatively insensitive to the conduit structure and geometry, thereby predicting the narrow band of tremor frequencies observed around the world. Moreover, the model predicts that as an eruption proceeds there will be an upward drift in both the maximum frequency and the total signal frequency bandwidth, the nature of which depends on the explosivity of the eruption, as observed.

  6. Strategic Petroleum Reserve (SPR) additional geologic site characterization studies, Bryan Mound Salt Dome, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Neal, J.T. [Sandia National Labs., Albuquerque, NM (United States); Magorian, T.R.; Ahmad, S. [Acres International Corp., Amherst, NY (United States)

    1994-11-01

    This report revises the original report that was published in 1980. Some of the topics covered in the earlier report were provisional and it is now practicable to reexamine them using new or revised geotechnical data and that obtained from SPR cavern operations, which involves 16 new caverns. Revised structure maps and sections show interpretative differences as compared with the 1980 report and more definition in the dome shape and caprock structural contours, especially a major southeast-northwest trending anomalous zone. The original interpretation was of westward tilt of the dome, this revision shows a tilt to the southeast, consistent with other gravity and seismic data. This interpretation refines the evaluation of additional cavern space, by adding more salt buffer and allowing several more caverns. Additional storage space is constrained on this nearly full dome because of low-lying peripheral wetlands, but 60 MMBBL or more of additional volume could be gained in six or more new caverns. Subsidence values at Bryan Mound are among the lowest in the SPR system, averaging about 11 mm/yr (0.4 in/yr), but measurement and interpretation issues persist, as observed values are about the same as survey measurement accuracy. Periodic flooding is a continuing threat because of the coastal proximity and because peripheral portions of the site are at elevations less than 15 ft. This threat may increase slightly as future subsidence lowers the surface, but the amount is apt to be small. Caprock integrity may be affected by structural features, especially the faulting associated with anomalous zones. Injection wells have not been used extensively at Bryan Mound, but could be a practicable solution to future brine disposal needs. Environmental issues center on the areas of low elevation that are below 15 feet above mean sea level: the coastal proximity and lowland environment combined with the potential for flooding create conditions that require continuing surveillance.

  7. Monte Carlo simulation model for economic evaluation of rubble mound breakwater protection in Harbors

    Institute of Scientific and Technical Information of China (English)

    Richard M. Males; Jeffrey A. Melby

    2011-01-01

    The US Army Corps of Engineers has a mission to conduct a wide array of programs in the arenas of water resources,including coastal protection.Coastal projects must be evaluated according to sound economic principles,and considerations of risk assessment and sea level change must be included in the analysis.Breakwaters are typically nearshore structures designed to reduce wave action in the lee of the structure,resulting in calmer waters within the protected area,with attendant benefits in terms of usability by navigation interests,shoreline protection,reduction of wave runup and onshore flooding,and protection of navigation channels from sedimentation and wave action.A common method of breakwater construction is the rubble mound breakwater,constructed in a trapezoidal cross section with gradually increasing stone sizes from the core out.Rubble mound breakwaters are subject to degradation from storms,particularly for antiquated designs with under-sized stones insufficient to protect against intense wave energy.Storm waves dislodge the stones,resulting in lowering of crest height and associated protective capability for wave reduction.This behavior happens over a long period of time,so a lifecycle model (that can analyze the damage progression over a period of years) is appropriate.Because storms are highly variable,a model that can support risk analysis is also needed.Economic impacts are determined by the nature of the wave climate in the protected area,and by the nature of the protected assets.Monte Carlo simulation (MCS)modeling that incorporates engineering and economic impacts is a worthwhile method for handling the many complexities involved in real world problems.The Corps has developed and utilized a number of MCS models to compare project alternatives in terms of their costs and benefits.This paper describes one such model,Coastal Structure simulation (CSsim) that has been developed specifically for planning level analysis of breakwaters.

  8. Strategic Petroleum Reserve (SPR) additional geologic site characterization studies, Bryan Mound Salt Dome, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Neal, J.T. [Sandia National Labs., Albuquerque, NM (United States); Magorian, T.R.; Ahmad, S. [Acres International Corp., Amherst, NY (United States)

    1994-11-01

    This report revises the original report that was published in 1980. Some of the topics covered in the earlier report were provisional and it is now practicable to reexamine them using new or revised geotechnical data and that obtained from SPR cavern operations, which involves 16 new caverns. Revised structure maps and sections show interpretative differences as compared with the 1980 report and more definition in the dome shape and caprock structural contours, especially a major southeast-northwest trending anomalous zone. The original interpretation was of westward tilt of the dome, this revision shows a tilt to the southeast, consistent with other gravity and seismic data. This interpretation refines the evaluation of additional cavern space, by adding more salt buffer and allowing several more caverns. Additional storage space is constrained on this nearly full dome because of low-lying peripheral wetlands, but 60 MMBBL or more of additional volume could be gained in six or more new caverns. Subsidence values at Bryan Mound are among the lowest in the SPR system, averaging about 11 mm/yr (0.4 in/yr), but measurement and interpretation issues persist, as observed values are about the same as survey measurement accuracy. Periodic flooding is a continuing threat because of the coastal proximity and because peripheral portions of the site are at elevations less than 15 ft. This threat may increase slightly as future subsidence lowers the surface, but the amount is apt to be small. Caprock integrity may be affected by structural features, especially the faulting associated with anomalous zones. Injection wells have not been used extensively at Bryan Mound, but could be a practicable solution to future brine disposal needs. Environmental issues center on the areas of low elevation that are below 15 feet above mean sea level: the coastal proximity and lowland environment combined with the potential for flooding create conditions that require continuing surveillance.

  9. Complete tissue expander coverage by musculo-fascial flaps in immediate breast mound reconstruction after mastectomy.

    Science.gov (United States)

    Alani, Harith A; Balalaa, Nahed

    2013-10-01

    Immediate breast reconstruction with tissue expander has become an increasingly popular procedure. Complete coverage of the expander by a musculofascial layer provides an additional well-vascularised layer, reducing the rate of possible complications of skin necrosis, prosthesis displacement, and the late capsular contracture. Complete expander coverage can be achieved by a combination of pectoralis major muscle and adjacent thoracic fascia in selected patients. Seventy-five breast mounds in 59 patients were reconstructed, in the first stage a temporary tissue expander inserted immediately after mastectomy and a musculofascial layer composed of the pectoralis major muscle, the serratus anterior fascia, and the superficial pectoral fascia were created to cover the expander. The first stage was followed months later by implant insertion. Minor and major complications were reported in a period of follow-up ranging from 24-42 months (mean 31 months). Complete musculofascial coverage of the tissue expander was a simple and easy to learn technique providing that the patient has a well-formed and intact superficial pectoral and serratus anterior fascia. From a total of 75 breast mounds reconstructed, major complications rate was 4% (overall rate of 19.8%), including major seroma (n = 4), haematoma (n = 1), partial skin loss (n = 3), wound dehiscence (n = 1), major infection (n = 2), severe capsule contracture (n = 1), and expander displacement (n = 3). The serratus anterior fascia and the superficial pectoral fascia flaps can be effectively used as an autologous tissue layer to cover the lower and the lateral aspect of tissue expanders in immediate breast reconstruction after mastectomy.

  10. Local to global: a collaborative approach to volcanic risk assessment

    Science.gov (United States)

    Calder, Eliza; Loughlin, Sue; Barsotti, Sara; Bonadonna, Costanza; Jenkins, Susanna

    2017-04-01

    Volcanic risk assessments at all scales present challenges related to the multitude of volcanic hazards, data gaps (hazards and vulnerability in particular), model representation and resources. Volcanic hazards include lahars, pyroclastic density currents, lava flows, tephra fall, ballistics, gas dispersal and also earthquakes, debris avalanches, tsunamis and more ... they can occur in different combinations and interact in different ways throughout the unrest, eruption and post-eruption period. Volcanoes and volcanic hazards also interact with other natural hazards (e.g. intense rainfall). Currently many hazards assessments consider the hazards from a single volcano but at national to regional scales the potential impacts of multiple volcanoes over time become important. The hazards that have the greatest tendency to affect large areas up to global scale are those transported in the atmosphere: volcanic particles and gases. Volcanic ash dispersal has the greatest potential to directly or indirectly affect the largest number of people worldwide, it is currently the only volcanic hazard for which a global assessment exists. The quantitative framework used (primarily at a regional scale) considers the hazard at a given location from any volcano. Flow hazards such as lahars and floods can have devastating impacts tens of kilometres from a source volcano and lahars can be devastating decades after an eruption has ended. Quantitative assessment of impacts is increasingly undertaken after eruptions to identify thresholds for damage and reduced functionality. Some hazards such as lava flows could be considered binary (totally destructive) but others (e.g. ash fall) have varying degrees of impact. Such assessments are needed to enhance available impact and vulnerability data. Currently, most studies focus on physical vulnerability but there is a growing emphasis on social vulnerability showing that it is highly variable and dynamic with pre-eruption socio

  11. Volcanic forcing in decadal forecasts

    Science.gov (United States)

    Ménégoz, Martin; Doblas-Reyes, Francisco; Guemas, Virginie; Asif, Muhammad; Prodhomme, chloe

    2016-04-01

    Volcanic eruptions can significantly impact the climate system, by injecting large amounts of particles into the stratosphere. By reflecting backward the solar radiation, these particles cool the troposphere, and by absorbing the longwave radiation, they warm the stratosphere. As a consequence of this radiative forcing, the global mean surface temperature can decrease by several tenths of degrees. However, large eruptions are also associated to a complex dynamical response of the climate system that is particularly tricky do understand regarding the low number of available observations. Observations seem to show an increase of the positive phases of the Northern Atlantic Oscillation (NAO) the two winters following large eruptions, associated to positive temperature anomalies over the Eurasian continent. The summers following large eruptions are generally particularly cold, especially over the continents of the Northern Hemisphere. Overall, it is really challenging to forecast the climate response to large eruptions, as it is both modulated by, and superimposed to the climate background conditions, largely driven themselves by internal variability at seasonal to decadal scales. This work describes the additional skill of a forecast system used for seasonal and decadal predictions when it includes observed volcanic forcing over the last decades. An idealized volcanic forcing that could be used for real-time forecasts is also evaluated. This work consists in a base for forecasts that will be performed in the context of the next large volcanic eruption.

  12. Quantitative physical models of volcanic phenomena for hazards assessment of critical infrastructures

    Science.gov (United States)

    Costa, Antonio

    2016-04-01

    Volcanic hazards may have destructive effects on economy, transport, and natural environments at both local and regional scale. Hazardous phenomena include pyroclastic density currents, tephra fall, gas emissions, lava flows, debris flows and avalanches, and lahars. Volcanic hazards assessment is based on available information to characterize potential volcanic sources in the region of interest and to determine whether specific volcanic phenomena might reach a given site. Volcanic hazards assessment is focussed on estimating the distances that volcanic phenomena could travel from potential sources and their intensity at the considered site. Epistemic and aleatory uncertainties strongly affect the resulting hazards assessment. Within the context of critical infrastructures, volcanic eruptions are rare natural events that can create severe hazards. In addition to being rare events, evidence of many past volcanic eruptions is poorly preserved in the geologic record. The models used for describing the impact of volcanic phenomena generally represent a range of model complexities, from simplified physics based conceptual models to highly coupled thermo fluid dynamical approaches. Modelling approaches represent a hierarchy of complexity, which reflects increasing requirements for well characterized data in order to produce a broader range of output information. In selecting models for the hazard analysis related to a specific phenomenon, questions that need to be answered by the models must be carefully considered. Independently of the model, the final hazards assessment strongly depends on input derived from detailed volcanological investigations, such as mapping and stratigraphic correlations. For each phenomenon, an overview of currently available approaches for the evaluation of future hazards will be presented with the aim to provide a foundation for future work in developing an international consensus on volcanic hazards assessment methods.

  13. A Volcanic Hydrogen Habitable Zone

    Science.gov (United States)

    Ramirez, Ramses M.; Kaltenegger, Lisa

    2017-03-01

    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  14. Critiques of the seismic hypothesis and the vegetation stabilization hypothesis for the formation of Mima mounds along the western coast of the U.S.

    Science.gov (United States)

    Gabet, Emmanuel J.; Burnham, Jennifer L. Horwath; Perron, J. Taylor

    2016-09-01

    A recent paper published in Geomorphology by Gabet et al. (2014) presents the results of a numerical model supporting the hypothesis that burrowing mammals build Mima mounds - small, densely packed hillocks found primarily in the western United States. The model is based on field observations and produces realistic-looking mounds with spatial distributions similar to real moundfields. Alternative explanations have been proposed for these Mima mounds, including formation by seismic shaking and vegetation-controlled erosion and deposition. In this short communication, we present observations from moundfields in the coastal states of the western U.S. that are incompatible with these alternative theories.

  15. Quiescent Diffusive and Fumarolic Volcanic Bromocarbon Emissions

    Science.gov (United States)

    Schwandner, F. M.; Giźe, A. P.; Seward, T. M.; Hall, P. A.; Dietrich, V. J.

    2002-12-01

    Future scenarios of declining atmospheric burdens of Ozone Depleting Substances (ODS) such as halocarbons after phase-out following international regulation (Montreal Protocol) vary strongly depending on what contribution from natural sources is taken into account. In addition, current and pre-industrial global atmospheric budgets of ODS are poorly balanced by known natural and anthropogenic sources of halocarbons (Butler, 2000). Brominated halocarbons have a high Ozone Depletion Potential, Br is at least 40x as efficient as Cl in polar stratospheric ozone destruction (Solomon et al., 1992). CH3Br is the dominant Br carrier to the stratosphere with sources being ca.: 32% anthropogenic, 39% natural, but ca. 29% unaccounted for (WMO, 1998). Natural sources have been reviewed recently (Gribble, 2000, Butler, 2000), including magmatic inorganic (Bureau, 2000) and volcanic organic sources (Rassmussen et al., 1980; Schwandner et al., 2002). CH3Br and other bromocarbons have been reported in non-eruptive volcanic gases previously (Jordan et al., 2000; Schwandner et al., 2000). Due to its capability to extremely rapidly hydrolyse (Gan et al., 1995), CH3Br should not be sampled by the caustic soda bottle technique as used by Jordan et al. (2000) whose samples also show signs of air contamination, but by cryogenic separation of steam with subsequent sorbent trapping, as used by Isidorov (1990), Wahrenberger (1996) and Schwandner et al. (2000, 2001). To contribute significantly to the natural Br budget, volcanic gases would have to at least contain 2 ppmv (dry gas) CH3Br, scaled to a global CO2 emission of 66 Tgy-1 (Stoiber, 1995) based on CO2 flux to halocarbon concentration correlations (e.g. CFC-11: R2=0.91, Schwandner et al., 2002). However, CH3Br is not the only volcanogenic bromocarbon. Analysis of diffusive flank and crater degassing on Vulcano island (Italy) showed a strong diffusive component of CH3Br and C2H5Br emissions in 60-100°C hot pristine unvegetated

  16. How Volcanism Controls Climate Change

    Science.gov (United States)

    Ward, P. L.

    2013-12-01

    Large explosive volcanoes eject megatons of sulfur dioxide into the lower stratosphere where it spreads around the world within months and is oxidized slowly to form a sulfuric-acid aerosol with particle sizes that grow large enough to reflect and scatter solar radiation, cooling Earth ~0.5C for up to 3 years. Explosive eruptions also deplete total column ozone ~6% causing up to 3C winter warming at mid-latitudes over continents. Global cooling predominates. Extrusive, basaltic volcanoes deplete ozone ~6% but do not eject much sulfur dioxide into the lower stratosphere, causing net global warming. Anthropogenic chlorofluorocarbons (CFCs) deplete ozone ~3% for up to a century while each volcanic eruption, even small ones, depletes ozone twice as much but for less than a decade through eruption of halogens and ensuing photochemical processes. The 2010 eruption of Eyjafjallajökull, the 2011 eruption of Grímsvötn, plus anthropogenic CFCs depleted ozone over Toronto Canada 14% in 2012, causing an unusually warm winter and drought. Total column ozone determines how much solar ultraviolet energy with wavelengths between 290 and 340 nanometers reaches Earth where it is absorbed most efficiently by the ocean. A 25% depletion of ozone increases the amount of this radiation reaching Earth by 1 W m-2 for overhead sun and 0.25 W m-2 for a solar zenith angle of 70 degrees. The tropopause is the boundary between the troposphere heated from below by a sun-warmed Earth and the stratosphere heated from above by the Sun through photodissociation primarily of oxygen and ozone. The mean annual height of the tropopause increased ~160 m between 1980 and 2004 at the same time that northern mid-latitude total column ozone was depleted by ~4%, the lower stratosphere cooled ~2C, the upper troposphere warmed ~0.1C, and mean surface temperatures in the northern hemisphere rose ~0.5C. Regional total ozone columns are observed to increase as rapidly as 20% within 5 hours with an associated 5

  17. Magma storage under Iceland's Eastern Volcanic Zone

    Science.gov (United States)

    Maclennan, J.; Neave, D.; Hartley, M. E.; Edmonds, M.; Thordarson, T.; Morgan, D. J.

    2014-12-01

    The Eastern Volcanic Zone (EVZ) of Iceland is defined by a number of volcanic systems and large basaltic eruptions occur both through central volcanoes (e.g. Grímsvötn) and on associated fissure rows (e.g. Laki, Eldgjá). We have collected a large quantity of micro-analytical data from a number of EVZ eruptions, with the aim of identifying common processes that occur in the premonitory stages of significant volcanic events. Here, we focus on the AD 1783 Laki event, the early postglacial Saksunarvatn tephra and the sub-glacially erupted Skuggafjöll tindar and for each of these eruptions we have >100 olivine-hosted or plagioclase-hosted melt inclusion analyses for major, trace and volatile elements. These large datasets are vital for understanding the history of melt evolution in the plumbing system of basaltic volcanoes. Diverse trace element compositions in melt inclusions hosted in primitive macrocrysts (i.e. Fo>84, An>84) indicate that the mantle melts supplied to the plumbing system of EVZ eruptions are highly variable in composition. Concurrent mixing and crystallisation of these melts occurs in crustal magma bodies. The levels of the deepest of these magma bodies are not well constrained by EVZ petrology, with only a handful of high-CO2 melt inclusions from Laki providing evidence for magma supply from >5 kbar. In contrast, the volatile contents of melt inclusions in evolved macrocrysts, which are close to equilibrium with the carrier liquids, indicate that final depths of inclusion entrapment are 0.5-2 kbar. The major element composition of the matrix glasses shows that the final pressure of equilibration between the melt and its macrocryst phases also occurred at 0.5-2 kbar. The relationship between these pressures and seismic/geodetic estimates of chamber depths needs to be carefully evaluated. The melt inclusion and macrocryst compositional record indicates that injection of porphyritic, gas-rich primitive melt into evolved/enriched and degassed shallow

  18. Precursory volcanic CO2 signals from space

    Science.gov (United States)

    Schwandner, Florian M.; Carn, Simon A.; Kataoka, Fumie; Kuze, Akihiko; Shiomi, Kei; Goto, Naoki

    2016-04-01

    Identification of earliest signals heralding volcanic unrest benefits from the unambiguous detection of precursors that reflect deviation of magmatic systems from metastable background activity. Ascent and emplacement of new basaltic magma at depth may precede eruptions by weeks to months. Transient localized carbon dioxide (CO2) emissions stemming from exsolution from depressurized magma are expected, and have been observed weeks to months ahead of magmatic surface activity. Detecting such CO2 precursors by continuous ground-based monitoring operations is unfortunately not a widely implemented method yet, save a handful of volcanoes. Detecting CO2 emissions from space offers obvious advantages - however it is technologically challenging, not the least due to the increasing atmospheric burden of CO2, against which a surface emission signal is hard to discern. In a multi-year project, we have investigated the feasibility of space-borne detection of pre-eruptive volcanic CO2 passive degassing signals using observations from the Greenhouse Gas Observing SATellite (GOSAT). Since 2010, we have observed over 40 active volcanoes from space using GOSAT's special target mode. Over 72% of targets experienced at least one eruption over that time period, demonstrating the potential utility of space-borne CO2 observations in non-imaging target-mode (point source monitoring mode). While many eruption precursors don't produce large enough CO2 signals to exceed space-borne detection thresholds of current satellite sensors, some of our observations have nevertheless already shown significant positive anomalies preceding eruptions at basaltic volcanoes. In 2014, NASA launched its first satellite dedicated to atmospheric CO2 observation, the Orbiting Carbon Observatory (OCO-2). Its observation strategy differs from the single-shot GOSAT instrument. At the expense of GOSAT's fast time series capability (3-day repeat cycle, vs. 16 for OCO-2), its 8-footprint continuous swath can slice

  19. Electrochemical sensor monitoring of volcanic gases

    Science.gov (United States)

    Roberts, Tjarda; Freshwater, Ray; Oppenheimer, Clive; Saffell, John; Jones, Rod; Griffiths, Paul; Braban, Christine; Mead, Iqbal

    2010-05-01

    Advances in instrumentation have fuelled a recent growth of interest in using portable sensor systems for environmental monitoring of pollution. Developments in wireless technology are enabling such systems to operate remotely and autonomously, generating a wealth of environmental data. We report here on the application of miniature Alphasense electrochemical sensors to the detection and characterisation of gases in volcanic plumes. A highly portable sensor system was developed to operate an array of 6 low cost electrochemical sensors to detect CO, H2, HCl, SO2, H2S and NO2 at 1 Hz. A miniature pump draws air over all sensors simultaneously (i.e. sensors arranged in parallel). The sensor output in these campaigns was logged on PDAs for real-time viewing, and later download (with a view to future data-streaming). The instrument was deployed at a number of volcanoes and was subject to extremely harsh conditions including highly acidic environments, low (Antarctic) temperatures, and transport over rough terrain. Analysis methods are demonstrated that consider calibration, cross-sensitivities of the sensors to multiple gases, differing sensor response times, temperature dependence, and background sensor drift with time. The analysis is applied to a range of plume field-measurements to extract gas concentrations ranging from 100's ppmv to sub-ppmv and to characterise the individual volcano emissions. Applications of similar sensor systems for real-time long-term monitoring of volcanic emissions (which may indicate and ultimately predict eruptive behavior), and UAV and balloon-borne plume sampling are now already being realised. This work focused on demonstrating the application of electrochemical sensors to monitoring of environmental pollution from volcanoes. Other applications for similar sensors include the near-source monitoring of industrial emissions, and of pollutant levels enhanced by traffic emissions in the urban environment.

  20. A high-resolution magnetic record of drift sediments in the neighbourhood of mound provinces in the Porcupine Seabight

    Science.gov (United States)

    Foubert, A.; van Rooij, D.; Henriet, J. P.

    2003-04-01

    The Porcupine Seabight forms a deep embayment in the Atlantic margin, off the south-western coast of Ireland. Very-high resolution seismic profiling, acquired since 1997, revealed the presence of large (carbonate) mounds. In general, the mounds are surrounded by bottom-current related deposits. The changes of seismic characteristics within the uppermost unit are interpreted as phases in a slope parallel drift under changing oceanographic conditions. The magnetic susceptibility records of two giant piston cores (MD01-2450 and MD01-2452), taken respectively in the drift sediments at the SE-flank of a Belgica mound (eastern flank of the basin) and above a Magellan mound (northern flank of the basin), were analysed in order to provide a relative time frame and to investigate possible changes in paleoceanography and paleoclimatology. Core MD01-2450 enabled us to propose a relative dating of over 74 ka, which has been confirmed by comparing the intensity of the NRM (Natural Remanent Magnetization) to ARM (Anhysteretic Remanent Magnetization) ratio with known intensity data. Another very remarkable observation in this core is the presence of iron sulfides between 630 and 1080 cm depth. This local iron sulfide enrichment could be the result of an anaerobic process with sulfate reduction during a period of non-steady-state diagenesis. Core MD01-2452, located in the sediments on top of the buried Magellan mounds, shows more pronounced paleoclimatological changes than the core located at the SE-flank of the Belgica mound. Moreover, typical HL can be recognized very clearly from magnetic susceptibility and P-wave velocity data during the latest glacial. The influence of European HE in the northern part of the basin could be less than on the eastern flank. However, we should be bear in mind that currents seem to be much weaker in the Magellan province than in the Belgica province. These weaker currents can be responsible for better preserved and thus more pronounced

  1. Geologic investigation of layered mound of Henry Crater, Mars: Implications for history of ancient hydrological activities in the region

    Science.gov (United States)

    Sarkar, Samarpita; Sinha, Rishitosh Kumar; Banerjee, Debabrata; Vijayan, S.

    2016-07-01

    Craters around the Schiaparelli Basin (sim460 km diameter; 2.71^circS 16.77^circE) on Mars are distributed in a unique combination that includes infilled craters with mound on their floors. The mounds have preserved intriguing layers in stratigraphy that has exposed pristine sets of geomorphic and geochemical signatures bearing strong implications towards understanding geological history of Mars. With a view to avail the maximum scientific benefit from this unique geological assemblage on Mars, we have carried out remote analysis of stratigraphy of layers exposed over Henry crater's (sim150 km diameter; 10.79^circN 23.45^circE) mound (rising sim2km from floor) to infer the origin and episodes of geological events occurred in the region. Henry crater is situated approximately 500 km northeast of Schiaparelli Basin. Using crater counting technique the age of the topmost surface of the crater mound is found to be sim3.64 Ga since the exposure of this strata post complete infilling. The stratigraphy of consistent and conformable layers in the crater interior acts as a proxy of the long-lived event of sediment deposition in a rather quiescent condition. Distinct layering can be traced across the crater from the mound to the crater wall across the floor. Evidence for differential erosion of deposited materials, wherein local geological setup developed in the different parts of the crater interior is preserved. Using MRO HiRISE & CTX images, distinct spatial distribution of morphological features distributed in stratigraphy is observed that reveals the dominant geological agents behind their formation, viz. temporal hydrological and eolian processes. The morphological features were aided with an understanding of the composition of the exposed sedimentary succession. MRO CRISM based mineralogical investigation reveals diagnostic signature of the hydrated sulfate mineral Kieserite. Based on the thermodynamic properties of Kieserite and apparent lack of desiccation cracks in

  2. Geology and biology of the "Sticky Grounds," shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

    Science.gov (United States)

    Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

    2016-01-01

    Shelf-margin carbonate mounds in water depths of 116–135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the “Sticky Grounds”, trend along slope, are 5–15 m in relief with base diameters of 5–30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve

  3. Unmanned aerial vehicle measurements of volcanic carbon dioxide fluxes

    Science.gov (United States)

    McGonigle, A. J. S.; Aiuppa, A.; Giudice, G.; Tamburello, G.; Hodson, A. J.; Gurrieri, S.

    2008-03-01

    We report the first measurements of volcanic gases with an unmanned aerial vehicle (UAV). The data were collected at La Fossa crater, Vulcano, Italy, during April 2007, with a helicopter UAV of 3 kg payload, carrying an ultraviolet spectrometer for remotely sensing the SO2 flux (8.5 Mg d-1), and an infrared spectrometer, and electrochemical sensor assembly for measuring the plume CO2/SO2 ratio; by multiplying these data we compute a CO2 flux of 170 Mg d-1. Given the deeper exsolution of carbon dioxide from magma, and its lower solubility in hydrothermal systems, relative to SO2, the ability to remotely measure CO2 fluxes is significant, with promise to provide more profound geochemical insights, and earlier eruption forecasts, than possible with SO2 fluxes alone: the most ubiquitous current source of remotely sensed volcanic gas data.

  4. Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America

    Directory of Open Access Journals (Sweden)

    D. Loyola

    2008-01-01

    Full Text Available Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash into the atmosphere, as well as several gases, including sulphur dioxide (SO2. These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

  5. Recent advances in ground-based ultraviolet remote sensing of volcanic SO2 fluxes

    Directory of Open Access Journals (Sweden)

    Euripides P. Kantzas

    2011-06-01

    Full Text Available Measurements of volcanic SO2 emission rates have been the mainstay of remote-sensing volcanic gas geochemistry for almost four decades, and they have contributed significantly to our understanding of volcanic systems and their impact upon the atmosphere. The last ten years have brought step-change improvements in the instrumentation applied to these observations, which began with the application of miniature ultraviolet spectrometers that were deployed in scanning and traverse configurations, with differential optical absorption spectroscopy evaluation routines. This study catalogs the more recent empirical developments, including: ultraviolet cameras; wide-angle field-of-view differential optical absorption spectroscopy systems; advances in scanning operations, including tomography; and improved understanding of errors, in particular concerning radiative transfer. Furthermore, the outcomes of field deployments of sensors during the last decade are documented, with respect to improving our understanding of volcanic dynamics and degassing into the atmosphere.

  6. Comparison ecological characteristics of mound-building mouse (mus spicilegus in two natural hotbeds of tularemia at North-West coast of the Black sea

    Directory of Open Access Journals (Sweden)

    І. T. Rusev

    2011-03-01

    Full Text Available The analysis of ecology-epizootic monitoring of North-West coast of the Black sea carried out in wintering seasons of 2004, 2005 and 2011 testifies the basic role of the Mound-building mouse (Mus spicilegus Petenyi, 1882 as a carrier of Francisella tularensis. Spatial distribution of the Mound-building mouse strongly dependson a biotope, geographical region and weather conditions of a specific season. Mice nests in the storage mounds are located normally at a depth of 20–40 cm under the food storage chamber. Average number of the mice in storage mounds is 3.08 ± 1.54 in the south of investigated region and 3.88 ± 2.63 – in the NE of the region.

  7. Source mechanisms of volcanic tsunamis.

    Science.gov (United States)

    Paris, Raphaël

    2015-10-28

    Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness. © 2015 The Author(s).

  8. Anomalous diffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2015-01-01

    Volcanic seismicity at Mt. Etna is studied. It is found that the associated stochastic process exhibits a subdiffusive phenomenon. The jump probability distribution well obeys an exponential law, whereas the waiting-time distribution follows a power law in a wide range. Although these results would seem to suggest that the phenomenon could be described by temporally-fractional kinetic theory based on the viewpoint of continuous-time random walks, the exponent of the power-law waiting-time distribution actually lies outside of the range allowed in the theory. In addition, there exists the aging phenomenon in the event-time averaged mean squared displacement, in contrast to the picture of fractional Brownian motion. Comments are also made on possible relevances of random walks on fractals as well as nonlinear kinetics. Thus, problems of volcanic seismicity are highly challenging for science of complex systems.

  9. Geochemical signatures of the diffuse CO2 emission from Brava volcanic system, Cape Verde

    Science.gov (United States)

    Rodriguez, F.; Bandomo, Z.; Barros, I.; Dias Fonseca, J.; Fernandes, P.; Rodrigues, J.; Melian Rodriguez, G.; Padron, E.; Dionis, S.; Sonia, S.; Gonçalves, A.; Fernandes, A.; Hernandez Perez, P. A.; Perez, N.

    2010-12-01

    Brava (67 km2) the smallest of the populated Cape Verde islands, lies at the southwestern end of the archipelagic crescent. Brava volcanic system has no documented historical eruptions, but its youthful volcanic morphology and the fact that earthquake swarms still occur indicate the potential for future eruptions. A geochemical survey of diffuse gas emissions was carried out in Brava island during February and March 2010. For this survey 228 sampling sites were selected all over the island to perform soil CO2 efflux measurements, using a portable accumulation chamber and an IR sensor, and soil temperature measurements at a depth of 30-50 cm. Soil gas samples were collected at 40 cm depth for chemical (He, H2, N2, CO2, CH4, Ar and O2) and isotopic (δ13C-CO2) analysis in 32 selected sampling sites. CO2 efflux values ranged from non-detectable up to 1.343 g m-2 d-1. To quantify the total diffuse CO2 emission from Brava volcanic system, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (˜2 g m-2 d-1), while peak levels (>1300 g m-2 d-1) were mainly identified at Vinagre and Baleia areas. The total diffuse CO2 output from Brava volcanic system was estimated about 41.6 t d-1. The analysis of the carbon isotopic signature of the CO2 in the soil atmosphere provides an insight for evaluating the origin of the diffuse CO2 emission. Observed δ13C-CO2 values ranged from -20.86 to -1.26 ‰. A binary plot of CO2 concentrations versus δ13C-CO2 values allows us to represent three major geochemical reservoirs (atmospheric air, volcanic gas, and biogenic gas) and their related mixing lines. The chemical and isotopic analysis of Brava soil gas samples suggest a mixing with deep-seated CO2 and biogenic gas for the diffuse CO2 emission from Brava volcanic system. The lack of visible volcanic gas emission in Brava highlights the importance of monitoring diffuse CO2 emission to improve its

  10. The sediment composition and predictive mapping of facies on the Propeller Mound—A cold-water coral mound (Porcupine Seabight, NE Atlantic)

    Science.gov (United States)

    Heindel, Katrin; Titschack, Jürgen; Dorschel, Boris; Huvenne, Veerle A. I.; Freiwald, André

    2010-10-01

    Here we provide a detailed qualitative and quantitative insight on recent sediment composition and facies distribution of a cold-water coral (CWC) mound using the example of the Propeller Mound on the Irish continental margin (Hovland Mound Province, Porcupine Seabight). Five facies types on Propeller Mound are defined: (1) living coral framework, (2) coral rubble, (3) dropstone, (4) hardground, representing the on-mound facies, and (5) hemipelagic sediment facies, which describes the off-mound area. This facies definition is based on already published video-data recorded by Remotely Operated Vehicle (ROV), photo-data of gravity cores, box cores, and dredges from sediment surfaces as well as on the composition of the sediment fraction coarser than 125 μm, which has been analyzed on five selected box cores. Sediment compositions of the living coral framework and coral rubble facies are rather similar. Both sediment types are mainly produced by corals (34 and 35 wt%, respectively), planktonic foraminifers (22 and 29 wt%, respectively), benthic foraminifers (both 7 wt%), and molluscs (21 and 10 wt%, respectively), whereas the living coral framework characteristically features additional brachiopods (6 wt%). Hardgrounds are well-lithified coral rudstones rich in coral fragments (>30 surf%), foraminifers, echinoderms, and bivalves. The dropstone facies and the hemipelagic sediment typically carry high amounts of lithoclasts (36 and 53 wt%, respectively) and planktonic foraminifers (35 and 32 wt%, respectively); however, their faunal diversity is low compared with the coral-dominated facies (12 and <2 wt% coral fragments, 7 and 6 wt% benthic foraminifers, and 4 and 0 wt% balanids). Using the maximum likelihood algorithm within ArcGIS 9.2, spatial prediction maps of the previously described mound facies are calculated over Propeller Mound and are based on mound morphology parameters, ground-truthed with the sedimentary and faunal information from box cores, photographs

  11. Volcanic mercury in Pinus canariensis

    Science.gov (United States)

    Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

    2013-08-01

    Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg-1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg-1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg-1) and bark (6.0 μg kg-1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

  12. Linking sedimentary sulfur and iron biogeochemistry to growth patterns of a cold-water coral mound in the Porcupine Basin, S.W. Ireland (IODP Expedition 307).

    Science.gov (United States)

    Wehrmann, L M; Titschack, J; Böttcher, M E; Ferdelman, T G

    2015-09-01

    Challenger Mound, a 150-m-high cold-water coral mound on the eastern flank of the Porcupine Seabight off SW Ireland, was drilled during Expedition 307 of the Integrated Ocean Drilling Program (IODP). Retrieved cores offer unique insight into an archive of Quaternary paleo-environmental change, long-term coral mound development, and the diagenetic alteration of these carbonate fabrics over time. To characterize biogeochemical carbon-iron-sulfur transformations in the mound sediments, the contents of dithionite- and HCl-extractable iron phases, iron monosulfide and pyrite, and acid-extractable calcium, magnesium, manganese, and strontium were determined. Additionally, the stable isotopic compositions of pore-water sulfate and solid-phase reduced sulfur compounds were analyzed. Sulfate penetrated through the mound sequence and into the underlying Miocene sediments, where a sulfate-methane transition zone was identified. Small sulfate concentration decreases (<7 mM) within the top 40 m of the mound suggested slow net rates of present-day organoclastic sulfate reduction. Increasing δ(34)S-sulfate values due to microbial sulfate reduction mirrored the decrease in sulfate concentrations. This process was accompanied by oxygen isotope exchange with water that was indicated by increasing δ(18)O-sulfate values, reaching equilibrium with pore-water at depth. Below 50 mbsf, sediment intervals with strong (34)S-enriched imprints on chromium-reducible sulfur (pyrite S), high degree-of-pyritization values, and semi-lithified diagenetic carbonate-rich layers characterized by poor coral preservation, were observed. These layers provided evidence for the occurrence of enhanced microbial sulfate-reducing activity in the mound in the past during periods of rapid mound aggradation and subsequent intervals of non-deposition or erosion when geochemical fronts remained stationary. During these periods, especially during the Early Pleistocene, elevated sulfate reduction rates facilitated

  13. Discernibility of Burial Mounds in High-Resolution X-Band SAR Images for Archaeological Prospections in the Altai Mountains

    Directory of Open Access Journals (Sweden)

    Timo Balz

    2016-09-01

    Full Text Available The Altai Mountains are a heritage-rich archaeological landscape with monuments in almost every valley. Modern nation state borders dissect the region and limit archaeological landscape analysis to intra-national areas of interest. Remote sensing can help to overcome these limitations. Due to its high precision, Synthetic Aperture Radar (SAR data can be a very useful tool for supporting archaeological prospections, but compared to optical imagery, the detectability of sites of archaeological interest is limited. We analyzed the limitations of SAR using TerraSAR-X images in different modes. Based on ground truth, the discernibility of burial mounds was analyzed in different SAR acquisition modes. We show that very-high-resolution TerraSAR-X staring spotlight images are very well suited for the task, with >75% of the larger mounds being discernible, while in images with a lower spatial resolution only a few large sites can be detected, at rates below 50%.

  14. Discovery and Significance of High CH4 Primary Fluid Inclusions in Reservoir Volcanic Rocks of the Songliao Basin, NE China

    Institute of Scientific and Technical Information of China (English)

    WANG Pujun; HOU Qijun; WANG Keyong; CHEN Shumin; CHENG Rihui; LIU Wanzhu; LI Quanlin

    2007-01-01

    Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that: (1) up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; (2) high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bearing CO2 reservoirs that are rich in helium and with a high 3He/4He ratio and which show reversed order of δ13C in alkane; (3) in gas reservoirs of such abiotic methane (>80%)and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42mole%, and the reversed order of δ13C in alkane is sometimes irregular in the corresponding gas pools;(4) a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.

  15. Submarine volcanoes along the Aegean volcanic arc

    Science.gov (United States)

    Nomikou, Paraskevi; Papanikolaou, Dimitrios; Alexandri, Matina; Sakellariou, Dimitris; Rousakis, Grigoris

    2013-06-01

    The Aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research. The basic data including swath bathymetric maps, air-gun profiles, underwater photos and samples analysis have been presented along the four main volcanic groups of the arc. The description concerns: (i) Paphsanias submarine volcano in the Methana group, (ii) three volcanic domes to the east of Antimilos Volcano and hydrothermal activity in southeast Milos in the Milos group, (iii) three volcanic domes east of Christiana and a chain of about twenty volcanic domes and craters in the Kolumbo zone northeast of Santorini in the Santorini group and (iv) several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the Nisyros group. The tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them. The NE-SW direction is dominant in the Santorini and Nisyros volcanic groups, located at the eastern part of the arc, where strike-slip is also present, whereas NW-SE direction dominates in Milos and Methana at the western part, where co-existence of E-W disrupting normal faults is observed. The volcanic relief reaches 1100-1200 m in most cases. This is produced from the outcrops of the volcanic centers emerging usually at 400-600 m depth and ending either below sea level or at high altitudes of 600-700 m on the islands. Hydrothermal activity at relatively high temperatures observed in Kolumbo is remarkable whereas low temperature phenomena have been detected in the Santorini caldera around Kameni islands and in the area southeast of Milos. In Methana and Nisyros, hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations.

  16. Wave Overtopping over Crown Walls and Run-up on Rubble Mound Breakwaters with Kolos Armour under Random Waves

    OpenAIRE

    A. Arunjith; Sannasiraj, S.A.; Sundar, V.

    2013-01-01

    The design of rubble mound structures like breakwaters and seawalls are influenced by the wave run-up and overtopping over them. The above phenomena largely depend on the type of the armour units as they directly interact with the incident waves. The hydrodynamic characteristics of various concrete armour units have been established by several researchers. A new armour block, ‘Kolos’, a modified version of Dolos, is considered in this study for a detailed investigation. An attempt is made to ...

  17. Trace elements and REE geochemistry of Middle Devonian carbonate mounds (Maïder Basin, Eastern Anti-Atlas, Morocco): Implications for early diagenetic processes

    Science.gov (United States)

    Franchi, Fulvio; Turetta, Clara; Cavalazzi, Barbara; Corami, Fabiana; Barbieri, Roberto

    2016-08-01

    Trace and rare earth elements (REEs) have proven their utility as tools for assessing the genesis and early diagenesis of widespread geological bodies such as carbonate mounds, whose genetic processes are not yet fully understood. Carbonates from the Middle Devonian conical mud mounds of the Maïder Basin (eastern Anti-Atlas, Morocco) have been analysed for their REE and trace element distribution. Collectively, the carbonates from the Maïder Basin mud mounds appear to display coherent REE patterns. Three different geochemical patterns, possibly related with three different diagenetic events, include: i) dyke fills with a normal marine REE pattern probably precipitated in equilibrium with seawater, ii) mound micrite with a particular enrichment of overall REE contents and variable Ce anomaly probably related to variation of pH, increase of alkalinity or dissolution/remineralization of organic matter during early diagenesis, and iii) haematite-rich vein fills precipitated from venting fluids of probable hydrothermal origin. Our results reinforce the hypothesis that these mounds were probably affected by an early diagenesis induced by microbial activity and triggered by abundance of dispersed organic matter, whilst venting may have affected the mounds during a later diagenetic phase.

  18. «Mud-mounds» en sedimentos lacustres someros del Mioceno medio de la cuenca de Madrid

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    Calvo, J. P.

    1985-12-01

    Full Text Available Several non-tuffaceous carbonate buildups have been recognized in middle Miocene sediments of the Madrid Basin. Facies associations lead to conclude that carbonate buildups developed in shallow lacustrine areas, Detailed morphology and internal structure of the buildups are shown. A dense, sometimes discontinuous, rhizolith network is displayed in the mud-mound cores whereas surficial dessicated crusts are commonly observed in the outer parto Small wedge-c1astic breccias from eroded flanks of the buildups have been locally distinguished as well. Mud-mound growth took place through successive stages controlled by lake level oscillations.

    Diversos edificios carbonáticos de carácter no tobáceo han sido reconocidos en sucesiones continentales correspondientes al Mioceno medio de la cuenca de Madrid. La asociación de facies en todos los casos observados conduce a caracterizar dichos edificios como propios de ambientes palustres o lacustres muy someros. Se describe en detalle la morfología y estructura interna de estos cuerpos cuyo núcleo aparece constituido por un espeso entramado de raíces con ciertas peculiaridades en sus rellenos. Distintas subfacies: núcleo, discontinuidades internas, corteza externa, brechas locales en los flancos , han sido distinguidas, sirviendo de base para la propuesta de un modelo de desarrollo en estadios sucesivos de los edificios, integrables bajo el término de "mud-mounds" en ambiente continental.

  19. Combining ER and GPR surveys for evidence of prehistoric landscape construction: case study at Mound City, Ohio, USA

    Science.gov (United States)

    Schneider, B. B.; Mandel, R. D.; Tsoflias, G. P.; De Vore, S. L.; Lynott, M.

    2016-06-01

    Mound City, located at the Hopewell Culture National Historical Park in south-central Ohio, USA, is a prehistoric earthwork (200 BC-500 AD) that consists of 24 mounds enclosed in a square embankment wall and is surrounded by eight pits. Recent excavation of two of these pits resulted in the discovery of a clay loam liner that appears to have been placed on the floor of the pits by a prehistoric society known as the Hopewell. The aim of this study was to determine the spatial pattern of this liner in one of the pits using non-invasive geophysical techniques, specifically electrical resistivity and ground-penetrating radar. Minimally invasive soil augers and a test trench yielded information that was used to corroborate interpretations of the geophysical data. The geophysical methods proved to be useful in locating and defining the remnants of the prehistoric clay loam liner, and the results of our investigation indicate that almost 50% of the liner still remains in the pit today. This discovery supports a new interpretation that the Hopewell excavated and preserved the pits at the Mound City site because they served as cultural landscape features.

  20. 土墩墓祭祀遗存考辨%A Study on the Sacrifice Remains of Mound Tombs

    Institute of Scientific and Technical Information of China (English)

    付琳

    2015-01-01

    土墩墓中所见的器物祭祀遗存一般都出现在丧葬过程中相对固定的环节,而且在土墩内摆放祭祀器物或挖掘祭坑的空间位置也存在一定规律可循。江南地区土墩墓中常见四类器物祭祀遗存形式,即“墓下祭祀”遗存、“墓前祭祀”遗存、“墩上祭祀”遗存和“墩脚祭祀”遗存。土墩墓中的“墓下建筑”遗存、人骨祭坑和燎祭遗存等可能与丧葬祭祀活动相关。%Sacrifices were often held at a certain time of funeral ceremonies. The positioning of the sac⁃rifice goods and the sacrifice pits seemed also following certain rules. Four forms of sacrifice remains are commonly seen in mound tombs in Jiangnan area: sacrifice within the tomb, sacrifice in front of the tomb, sacrifice on the top of the mound, and sacrifice at the foot of the mound. The under-tomb structural remains, human sacrifice remains and burning sacrifice remains may be related to the sacrifice activities in funerals.

  1. Microfossils, a Key to Unravel Cold-Water Carbonate Mound Evolution through Time: Evidence from the Eastern Alboran Sea.

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    Claudio Stalder

    Full Text Available Cold-water coral (CWC ecosystems occur worldwide and play a major role in the ocean's carbonate budget and atmospheric CO2 balance since the Danian (~65 m.y. ago. However their temporal and spatial evolution against climatic and oceanographic variability is still unclear. For the first time, we combine the main macrofaunal components of a sediment core from a CWC mound of the Melilla Mounds Field in the Eastern Alboran Sea with the associated microfauna and we highlight the importance of foraminifera and ostracods as indicators of CWC mound evolution in the paleorecord. Abundances of macrofauna along the core reveal alternating periods dominated by distinct CWC taxa (mostly Lophelia pertusa, Madrepora oculata that correspond to major shifts in foraminiferal and ostracod assemblages. The period dominated by M. oculata coincides with a period characterized by increased export of refractory organic matter to the seafloor and rather unstable oceanographic conditions at the benthic boundary layer with periodically decreased water energy and oxygenation, variable bottom water temperature/density and increased sediment flow. The microfaunal and geochemical data strongly suggest that M. oculata and in particular Dendrophylliidae show a higher tolerance to environmental changes than L. pertusa. Finally, we show evidence for sustained CWC growth during the Alleröd-Younger-Dryas in the Eastern Alboran Sea and that this period corresponds to stable benthic conditions with cold/dense and well oxygenated bottom waters, high fluxes of labile organic matter and relatively strong bottom currents.

  2. Dig-face monitoring during excavation of a radioactive plume at Mound Laboratory, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Josten, N.E.; Gehrke, R.J.; Carpenter, M.V.

    1995-12-01

    A dig-face monitoring system consists of onsite hardware for collecting information on changing chemical, radiological, and physical conditions in the subsurface soil during the hazardous site excavation. A prototype dig-face system was take to Mount Laboratory for a first trial. Mound Area 7 was the site of historical disposals of {sup 232}Th, {sup 227}Ac, and assorted debris. The system was used to monitor a deep excavation aimed at removing {sup 227}Ac-contaminated soils. Radiological, geophysical, and topographic sensors were used to scan across the excavation dig-face at four successive depths as soil was removed. A 3-D image of the contamination plumes was developed; the radiation sensor data indicated that only a small portion of the excavated soil volume was contaminated. The spatial information produced by the dig-face system was used to direct the excavation activities into the area containing the {sup 227}Ac and to evaluate options for handling the separate {sup 232}Th plume.

  3. Columbia Estuary Ecosystem Restoration Program: Restoration Design Challenges for Topographic Mounds, Channel Outlets, and Reed Canarygrass

    Energy Technology Data Exchange (ETDEWEB)

    Diefenderfer, Heida L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Borde, Amy B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sinks, Ian A. [Columbia Land Trust, Vancouver, WA (United States); Cullinan, Valerie I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zimmerman, Shon A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-08-31

    The purpose of this study was to provide science-based information to practitioners and managers of restoration projects in the Columbia Estuary Ecosystem Restoration Program (CEERP) regarding aspects of restoration techniques that currently pose known challenges and uncertainties. The CEERP is a program of the Bonneville Power Administration (BPA) and the U.S. Army Corps of Engineers (Corps), Portland District, in collaboration with the National Marine Fisheries Service and five estuary sponsors implementing restoration. The estuary sponsors are Columbia Land Trust, Columbia River Estuary Study Taskforce, Cowlitz Tribe, Lower Columbia Estuary Partnership, and Washington Department of Fish and Wildlife. The scope of the research conducted during federal fiscal year 2015 included three aspects of hydrologic reconnection that were selected based on available scientific information and feedback from restoration practitioners during project reviews: the design of mounds (also called hummocks, peninsulas, or berms); the control of reed canarygrass (Phalaris arundinaceae); and aspects of channel network design related to habitat connectivity for juvenile salmonids.

  4. Geophysical Surveys at Khirbat Faynan, an Ancient Mound Site in Southern Jordan

    Directory of Open Access Journals (Sweden)

    Alexandre Novo

    2012-01-01

    Full Text Available Faynan in Jordan contains the largest copper ore resource zone in the southern Levant (Israel, Jordan, Palestinian territories, Lebanon, Syria, and the Sinai Peninsula. Located 50 km southeast of the Dead Sea, it is home to one of the world’s best-preserved ancient mining and metallurgy districts encompassing an area of ca. 400 km2. During the past three decades, archaeologists have carried out numerous excavations and surveys recording hundreds of mines and sites related to metallurgical activities that span the past 10 millennia. Khirbat Faynan (Biblical Punon, is situated in the main Faynan Valley and is the largest (ca. 15 ha settlement site in the region and has remained unexcavated until 2011. As Jordan’s most southern mound site with indications of widespread ancient architecture, we employed a suite of noninvasive geophysical survey methods to identify areas suitable for excavation. Earlier geophysical surveys were carried out in the Faynan region by our team in the late 1990s when only EMI (electromagnetic induction proved successful, but with relatively poor resolution. As reported here, by 2011, improvements in data processing software and 3D ERT (electrical resistivity tomography sampling protocols made it possible to greatly improve the application of noninvasive geophysical surveying in this hyperarid zone.

  5. Unraveling landscapes with phytogenic mounds (nebkhas): An exploration of spatial pattern

    Science.gov (United States)

    Quets, Jan J.; Temmerman, Stijn; El-