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Sample records for rock salt formations

  1. Excavation Damaged Zones In Rock Salt Formations

    SciTech Connect

    Jockwer, N.; Wieczorek, K.

    2008-07-01

    Salt formations have long been proposed as potential host rocks for nuclear waste disposal. After the operational phase of a repository the openings, e.g., boreholes, galleries, and chambers, have to be sealed in order to avoid the release of radionuclides into the biosphere. For optimising the sealing techniques knowledge about the excavation damaged zones (EDZ) around these openings is essential. In the frame of a project performed between 2004 and 2007, investigations of the EDZ evolution were performed in the Stassfurt halite of the Asse salt mine in northern Germany. Three test locations were prepared in the floor of an almost 20 year old gallery on the 800-m level of the Asse mine: (1) the drift floor as existing, (2) the new drift floor shortly after removing of a layer of about 1 m thickness of the floor with a continuous miner, (3) the new drift floor 2 years after cutting off the 1-m layer. Subject of investigation were the diffusive and advective gas transport and the advective brine transport very close to the opening. Spreading of the brine was tracked by geo-electric monitoring in order to gain information about permeability anisotropy. Results obtained showed that EDZ cut-off is a useful method to improve sealing effectiveness when constructing technical barriers. (authors)

  2. Impact of solid second phases on deformation mechanisms of naturally deformed salt rocks (Kuh-e-Namak, Dashti, Iran) and rheological stratification of the Hormuz Salt Formation

    NASA Astrophysics Data System (ADS)

    Závada, P.; Desbois, G.; Urai, J. L.; Schulmann, K.; Rahmati, M.; Lexa, O.; Wollenberg, U.

    2015-05-01

    Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' second phase bearing rock salt and 'strong' pure rock salt types are studied for deformation mechanisms using detailed quantitative microstructural study. While the solid inclusions rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although the flow in both, the recrystallized "dirty" and "clean" salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS), transgranular microcracking and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts observed in the field outcrops are explained by: 1) enhanced ductility of "dirty" salts due to increased diffusion rates along the solid inclusion-halite contacts than along halite-halite contacts, and 2) slow rates of intergranular diffusion due to dissolved iron and inhibited dislocation creep due to hematite inclusions for "clean" salt types Rheological contrasts inferred by microstructural analysis between both salt rock classes apply in general for the "dirty" salt forming Lower Hormuz and the "clean" salt forming the Upper Hormuz of the Hormuz Formation and imply strain rate gradients or decoupling along horizons of mobilized salt types of different composition and microstructure.

  3. Authigenic K-feldspar in salt rock (Haselgebirge Formation, Eastern Alps)

    NASA Astrophysics Data System (ADS)

    Leitner, Christoph

    2015-04-01

    The crystallisation of authigenic quartz under low temperature, saline conditions is well known (Grimm, 1962). Also the growth of low temperature authigenic feldspar in sediments is a long known phenomenon (Kastner & Siever, 1979; Sandler et al., 2004). In this study we intend to show that halite (NaCl) is a major catalyser for authigenic mineral growth. During late Permian (c. 255-250 Ma), when the later Eastern Alps were located around north of the equator, the evaporites of the Haselgebirge Formation were deposited (Piller et al., 2004). The Haselgebirge Fm. consists in salt mines of a two-component tectonite of c. 50 % halite and 50 % sedimentary clastic and other evaporite rocks (Spötl 1998). Most of the clastic rocks are mud- to siltstones ("mudrock"). During this study, we investigated rare sandstones embedded in salt rock form four Alpine salt mines. Around 40 polished thin sections were prepared by dry grinding for thin section analysis and scanning electron microscopy. The sandstones consist mainly of quartz, K-feldspar, rock fragments, micas, accessory minerals and halite in the pore space. They are fine grained and well sorted. Mudrock clasts in sandstone were observed locally, and also coal was observed repeatedly. Asymmetric ripples were found only in the dimension of millimeters to centimeters. Euhedral halite crystals in pores indicate an early presence of halite. During early diagenesis, authigenic minerals crystallized in the following chronological order. (1) Where carbonate (mainly magnesite) occurred, it first filled the pore space. Plant remains were impregnated with carbonate. (2) Halite precipitated between the detritic sandstone grains. Carbonate grains can be completely embedded in halite. (3) K-feldspar and quartz grains usually expose a detritic core and a later grown euhedral inclusion free rim. Euhedral rims of K-feldspar often also enclose a halite core. K-feldspar replaced the pre-existing halite along former grain boundaries of

  4. Rheological stratification of the Hormuz Salt Formation in Iran - microstructural study of the dirty and pure rock salts from the Kuh-e-Namak (Dashti) salt diapir

    NASA Astrophysics Data System (ADS)

    Závada, Prokop; Desbois, Guillaume; Urai, Janos; Schulmann, Karel; Rahmati, Mahmoud; Lexa, Ondrej; Wollenberg, Uwe

    2014-05-01

    Significant viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' terrestrial debris bearing rock salt types and 'strong' pure rock salt types are questioned for deformation mechanisms using detailed quantitative microstructural study including crystallographic preferred orientation (CPO) mapping of halite grains. While the solid impurity rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts (debris free) reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although flow in both, the recrystallized dirty and clean salt types is accommodated by combined mechanisms of pressure-solution creep (PS), grain boundary sliding (GBS) and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts are explained by significantly slower rates of intergranular diffusion and piling up of dislocations at hematite inclusions in clean salt types. Porphyroclasts of clean salts deform by semi-brittle and plastic mechanisms with intra-crystalline damage being induced also by fluid inclusions that explode in the crystals at high fluid pressures. Boudins of clean salt types with coarse grained and original sedimentary microstructure suggest that clean rock salts are associated with dislocation creep dominated power law flow in the source layer and the diapiric stem. Rheological contrasts between both rock salt classes apply in general for the variegated and terrestrial debris rich ("dirty") Lower Hormuz and the "clean" rock salt forming the Upper Hormuz, respectively, and suggest that large strain rate gradients likely exist along horizons of mobilized salt types of different composition and microstructure.

  5. Metallic sulfide deposits in Winnefield salt dome, Louisiana: evidence for episodic introduction of metalliferous brines during cap rock formation

    SciTech Connect

    Ulrich, M.R.

    1984-09-01

    Winnfield dome is a shallow piercement salt structure that penetrates Late Jurassic through early Tertiary siliciclastic and carbonate strata of the North Louisiana basin. Quarrying operations in the calcite and anhydrite portions of the cap rock have exposed zones of metallic sulfides and barite. A roughly laminated massive sulfide lens is exposed at the calcite to anhydrite transition zone. These sulfide concentrations are believed to have originated from the interaction of metalliferous basinal brines with reduced sulfur trapped within the cap rock. Textural relationships and variations in chemical compositions between the sulfide layers in the anhydrite portion of the cap rock suggest that distinct pulses of metalliferous brines were responsible for the sulfide concentrations. Anhydrite grains outside the mineralized areas are deformed and tightly intergrown. These textures suggest that mineralizing fluids were introduced episodically along the salt and anhydrite interface at the zone of salt dissolution before that portion of the anhydrite zone was compressed and accreted to overlying anhydrite cap rock. Therefore, the earliest formed sulfides originating by this mechanism occur at the top of the anhydrite cap rock zone, whereas the last sulfides to form are found at the base. Extensive sulfide concentrations along the anhydrite-calcite contact suggest that this contact also acted as a permeable zone allowing metalliferous brines into the cap rock. Textural and compositional relationships suggest that sulfides that formed along the anhydrite-calcite contact are locally superimposed on sulfides that formed at the salt-anhydrite contact.

  6. Fracture and Healing of Rock Salt Related to Salt Caverns

    SciTech Connect

    Chan, K.S.; Fossum, A.F.; Munson, D.E.

    1999-03-01

    In recent years, serious investigations of potential extension of the useful life of older caverns or of the use of abandoned caverns for waste disposal have been of interest to the technical community. All of the potential applications depend upon understanding the reamer in which older caverns and sealing systems can fail. Such an understanding will require a more detailed knowledge of the fracture of salt than has been necessary to date. Fortunately, the knowledge of the fracture and healing of salt has made significant advances in the last decade, and is in a position to yield meaningful insights to older cavern behavior. In particular, micromechanical mechanisms of fracture and the concept of a fracture mechanism map have been essential guides, as has the utilization of continuum damage mechanics. The Multimechanism Deformation Coupled Fracture (MDCF) model, which is summarized extensively in this work was developed specifically to treat both the creep and fracture of salt, and was later extended to incorporate the fracture healing process known to occur in rock salt. Fracture in salt is based on the formation and evolution of microfractures, which may take the form of wing tip cracks, either in the body or the boundary of the grain. This type of crack deforms under shear to produce a strain, and furthermore, the opening of the wing cracks produce volume strain or dilatancy. In the presence of a confining pressure, microcrack formation may be suppressed, as is often the case for triaxial compression tests or natural underground stress situations. However, if the confining pressure is insufficient to suppress fracture, then the fractures will evolve with time to give the characteristic tertiary creep response. Two first order kinetics processes, closure of cracks and healing of cracks, control the healing process. Significantly, volume strain produced by microfractures may lead to changes in the permeability of the salt, which can become a major concern in

  7. Rock-salt structure lithium deuteride formation in liquid lithium with high-concentrations of deuterium: a first-principles molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Chen, Mohan; Abrams, T.; Jaworski, M. A.; Carter, Emily A.

    2016-01-01

    Because of lithium’s possible use as a first wall material in a fusion reactor, a fundamental understanding of the interactions between liquid lithium (Li) and deuterium (D) is important. We predict structural and dynamical properties of liquid Li samples with high concentrations of D, as derived from first-principles molecular dynamics simulations. Liquid Li samples with four concentrations of inserted D atoms (LiDβ , β =0.25 , 0.50, 0.75, and 1.00) are studied at temperatures ranging from 470 to 1143 K. Densities, diffusivities, pair distribution functions, bond angle distribution functions, geometries, and charge transfer between Li and D atoms are calculated and analyzed. The analysis suggests liquid-solid phase transitions can occur at some concentrations and temperatures, forming rock-salt LiD within liquid Li. We also observe formation of some D2 molecules at high D concentrations.

  8. Dynamics of rock varnish formation

    SciTech Connect

    Raymond, R. Jr.; Reneau, S.L.; Guthrie, G.D. Jr.; Bish, D.L.; Harrington, C.D.

    1991-01-01

    Our studies of rock varnish from the southwestern United States suggest that the Mn-phase in rock varnish has neither the chemistry nor the crystal structure of birnessite. Rather, the Mn-rich phase is non-crystalline and contains Ba, Ca, Fe, Al, and P. Unknowns concerning the formation of this non-crystalline Mn phase must be resolved before researchers are able to define chemical parameters of rock varnish formation based upon conditions of formation of the Mn phase. 6 refs., 9 figs.

  9. Salt Attack on Rocks and Expansion of Soils on Mars

    NASA Astrophysics Data System (ADS)

    Vaniman, D. T.; Bish, D. L.; Chipera, S. J.; Carey, J. W.

    2004-12-01

    Salt-rich sediments observed by the MER rover Opportunity at Meridiani Planum show that brines have been present on Mars in the past, but a role for groundwater in widespread rock weathering and soil formation is uncertain. Experiments by several groups suggest instead the action of acid fog over long time spans, with episodic input of volcanic gases, as a more significant agent of Mars weathering. Salt minerals formed in these acid weathering experiments consistently include gypsum and alunogen, with epsomite or hexahydrite forming where olivine provides a source of Mg. Analogous to the martian acid fog scenario are terrestrial acid rain or acid fog attacks on building and monument stone by chemical action and mechanical wedging through growth of gypsum, anhydrite, epsomite, hexahydrite, kieserite, and other sulfate minerals. Physical effects can be aggressive, operating by both primary salt growth and hydration of anhydrous or less-hydrous primary salts. In contrast, soils evolve to states where chemical attack is lessened and salt mineral growth leads to expansion with cementation; in this situation the process becomes constructive rather than destructive. We have made synthetic salt-cemented soils (duricrusts) from clays, zeolites, palagonites and other media mixed with ultrapure Mg-sulfate solutions. Although near-neutral in pH, these solutions still exchange or leach Ca from the solids to form cements containing gypsum as well as hexahydrite. At low total P (1 torr) and low RH (<1%) hexahydrite becomes amorphous but gypsum does not. If allowed to rehydrate from vapor at higher RH, the Mg-sulfate component of the duricrust expands by formation of a complex mixture of Mg-sulfate phases with various hydration states. The expanded form is retained even if the duricrust is again dehydrated, suggesting that soil porosity thus formed is difficult to destroy. These processes can be considered in the context of Viking, Pathfinder, and MER evidence for differing salt

  10. Changes in rock salt permeability due to nearby excavation

    SciTech Connect

    Stormont, J C; Howard, C L

    1991-07-01

    Changes in brine and gas permeability of rock salt as a result of nearby excavation (mine-by) have been measured from the underground workings of the WIPP facility. Prior to the mine-by, the formation responds as a porous medium with a very low brine permeability, a significant pore (brine) pressure and no measurable gas permeability. The mine-by excavation creates a dilated, partially saturated zone in the immediate vicinity of the excavation with an increased permeability to brine and a measurable permeability to gas. The changes in hydrologic properties are discussed in the context of pore structure changes.

  11. Creep healing of fractures in rock salt

    SciTech Connect

    Costin, L. S.; Wawersik, W. R.

    1980-08-01

    Fracture and healing experiments were performed on specimens of bedded salt from the Salado formation, southeastern New Mexico. Short rod specimens (100 mm in diameter) were loaded to failure in tension. During each test, a crack was initiated along the axis of the specimen. The fracture toughness of the salt was determined from the resulting load-crack opening displacement record. After the test, each specimen was pieced back together, jacketed and placed in a pressure vessel under hydrostatic pressure for several days. The confining pressure (10 to 35 MPa), temperature (22 to 100/sup 0/C) and healing time (4 to 8 days) were varied to determine the effect of each on the healing process. Upon removal from the pressure vessel, each sample was retested and the toughness of the healed fracture was determined. Results show that the salt specimens regained 70 to 80% of their original strength under all conditions except at the lowest temperature and pressure where specimens regained only 20 to 30% of their original strength. It is suspected that the primary mechanism involved is creep of asperities along the fracture surface which forms an interlocking network. Thus, the healing pressure is probably the most significant variable.

  12. Deformation-assisted fluid percolation in rock salt.

    PubMed

    Ghanbarzadeh, Soheil; Hesse, Marc A; Prodanović, Maša; Gardner, James E

    2015-11-27

    Deep geological storage sites for nuclear waste are commonly located in rock salt to ensure hydrological isolation from groundwater. The low permeability of static rock salt is due to a percolation threshold. However, deformation may be able to overcome this threshold and allow fluid flow. We confirm the percolation threshold in static experiments on synthetic salt samples with x-ray microtomography. We then analyze wells penetrating salt deposits in the Gulf of Mexico. The observed hydrocarbon distributions in rock salt require that percolation occurred at porosities considerably below the static threshold due to deformation-assisted percolation. Therefore, the design of nuclear waste repositories in salt should guard against deformation-driven fluid percolation. In general, static percolation thresholds may not always limit fluid flow in deforming environments. PMID:26612949

  13. Influences of salt structures on reservoir rocks in block L-2, Dutch continental shelf

    SciTech Connect

    Dronkert, H. ); Remmelts, G. )

    1993-09-01

    In the subsurface of the Netherlands Continental Shelf, thick layers of Zechstein salt have developed into salt domes and ridges that pierce through the overlying formations. To measure the range of lateral influence of the salt in these structures on the sandstone reservoir rocks of the Mesozoic sequence, a cementation model was developed. The target area, Block L-2, was chosen for the presence of salt domes, wells, and reservoir rocks. The L-2 case study has been performed on two Triassic sandstone intervals. The lower, Volpriehausen, sandstone showed halite cementation in one well, located within several 100 m from a salt dome. Four other wells, located more than 1.5 km from a salt structure, did not show any signs of halite cementation. Therefore, the lateral influence of salt domes on the surrounding reservoir rock is, in this case, limited to less than 1.5 km at 3-4 km depth. A slightly shallower Triassic sandstone (Detfurth) shows more frequent halite cementation. This cementation can be attributed to early seepage from overlying Rot salt brines.Triassic Rot salt is present above depletion areas of the Zechstein salt structures, and in such a way the seepage can be seen as an indirect influence of the salt structures.

  14. Model for transient creep of southeastern New Mexico rock salt

    SciTech Connect

    Herrmann, W; Wawersik, W R; Lauson, H S

    1980-11-01

    In a previous analysis, existing experimental data pertaining to creep tests on rock salt from the Salado formation of S.E. New Mexico were fitted to an exponential transient creep law. While very early time portions of creep strain histories were not fitted very well for tests at low temperatures and stresses, initial creep rates in particular generally being underestimated, the exponential creep law has the property that the transient creep strain approaches a finite limit with time, and is therefore desirable from a creep modelling point of view. In this report, an analysis of transient creep is made. It is found that exponential transient creep can be related to steady-state creep through a universal creep curve. The resultant description is convenient for creep analyses where very early time behavior is not important.

  15. Microbial biodiversity in Alpine Permo-Triassic rock salt

    NASA Astrophysics Data System (ADS)

    Radax, C.; Wieland, H.; Pfaffenhuemer, M.; Leuko, S.; Rittmann, S.; Weidler, G.; Gruber, C.; Stan-Lotter, H.

    2003-04-01

    Alpine Permo-Triassic rock salt (age 200-250 million years) was shown several times to contain living extremely halophilic Archaea. These organisms might stem from ancient populations that became entrapped and persisted in the rock salt since then. For this reason, rock salt is considered a promising model system for the search for bacterial extraterrestrial life. In our studies on biodiversity in Alpine rock salt, we employed both culture-dependent and culture-independent, PCR-based methods. The latter approach indicated the presence of at least 12 distinct sequence types (phylotypes) in our samples, all of which belonged to the extremely halophilic Archaea. None of the recovered sequences was identical to sequences from databases, suggesting the avoidance of contaminants during experimental procedures. Two phylotypes could be assigned to taxonomically described members of this family; the remaining ten phylotypes appeared only remotely related to known genera of the extremely halophilic Archaea. In contrast, attempts to isolate organisms from the same sample on 15 different growth media so far yielded only two groups of isolates that could be differentiated based on their 16S rRNA genes. One group was very similar to Halococcus strains that we frequently isolated from Alpine rock salt; the other group was closely correlated to one of our novel phylotypes. Analyses of whole cell protein patterns allowed to further differentiate the latter group into two different subgroups that could not be distinguished at the molecular level. These results show that both culture-dependent and culture-independent strategies have to be applied in order to obtain a more complete view of microbial biodiversity in Permo-Triassic rock salt: culture-independent methods yield information on the gross microbial diversity in rock salt, whereas subtle differences can currently only be registered between cultivated strains.

  16. Damage-induced nonassociated inelastic flow in rock salt

    SciTech Connect

    Chan, K.S.; Bodner, S.R.; Brodsky, N.S.; Fossum, A.F.

    1993-06-01

    The multi-mechanism deformation coupled fracture model recently developed by CHAN, et al. (1992), for describing time-dependent, pressure-sensitive inelastic flow and damage evolution in crystalline solids was evaluated against triaxial creep experiments on rock salt. Guided by experimental observations, the kinetic equation and the flow law for damage-induced inelastic flow in the model were modified to account for the development of damage and inelastic dilatation in the transient creep regime. The revised model was then utilized to obtain the creep response and damage evolution in rock salt as a function of confining pressure and stress difference. Comparison between model calculation and experiment revealed that damage-induced inelastic flow is nonassociated, dilatational, and contributes significantly to the macroscopic strain rate observed in rock salt deformed at low confining pressures. The inelastic strain rate and volumetric strain due to damage decrease with increasing confining pressures, and all are suppressed at sufficiently high confining pressures.

  17. Magnetic coupling at perovskite and rock-salt structured interfaces

    SciTech Connect

    Matvejeff, M.; Ahvenniemi, E.; Takahashi, R.; Lippmaa, M.

    2015-10-05

    We study magnetic coupling between hole-doped manganite layers separated by either a perovskite or a rock-salt barrier of variable thickness. Both the type and the quality of the interface have a strong impact on the minimum critical barrier thickness where the manganite layers become magnetically decoupled. A rock-salt barrier layer only 1 unit cell (0.5 nm) thick remains insulating and is able to magnetically de-couple the electrode layers. The technique can therefore be used for developing high-performance planar oxide electronic devices such as magnetic tunnel junctions and quantum well structures that depend on magnetically and electronically sharp heterointerfaces.

  18. Grain Boundary Wetting In The Stressed Rock Salt

    NASA Astrophysics Data System (ADS)

    Traskine, V.; Skvortsova, Z.; Barrallier, L.

    stress above 0.8 MPa tend to stop the brine infiltration. Extracting the intergranular energy distribution parameters from the Herring formula for the dihedral angles along triple lines allows to estimate the effec- tive increments to grain boundary energy due to shear stresses. A linear relationship between this interfacial energy term and the square of shear stress gives a formally Griffith-like criterion for GBW based on the interfacial and elastic energy balance. Applying the results to the rock salt formations will provide a new insight into the percolation approach to their transport characteristics.

  19. Astrobiology with haloarchaea from Permo-Triassic rock salt

    NASA Astrophysics Data System (ADS)

    Stan-Lotter, H.; Radax, C.; Gruber, C.; Legat, A.; Pfaffenhuemer, M.; Wieland, H.; Leuko, S.; Weidler, G.; Kömle, N.; Kargl, G.

    2002-10-01

    Several viable halophilic archaebacteria were isolated previously from rock salt of Permo-Triassic age in an Austrian salt mine; one of these strains was the first to be recognized as a novel species from subterranean halite and was designated Halococcus salifodinae. The halophilic microorganisms have apparently survived in the salt sediments over extremely long periods of time. Halobacteria could therefore be suitable model organisms for exploring the possibility of long-term survival of microbes on other planets, in particular, since extraterrestrial halite has been detected in meteorites and is assumed to be present in the subsurface ocean on Europa. Our efforts are directed at the identification of the microbial content of ancient rock salt and the development of procedures for the investigation of the halobacterial response to extreme environmental conditions. Using modified culture media, further halophilic strains were isolated from freshly blasted rock salt and bore cores; in addition, growth of several haloarchaea was substantially improved. Molecular methods indicated the presence of at least 12 different 16S rRNA gene species in a sample of Alpine rock salt, but these strains have not been cultured yet. The exploration of Mars is a target of space missions in the 21st century; therefore, testing the survival of haloarchaea under conditions comparable to present-day Mars, using a simulation chamber, was begun. Preliminary results with Halococcus and Halobacterium species suggested at least tenfold higher survival rates when cells were kept in liquid brines than under dry conditions; staining of cells with the LIVE DEAD kit, which discriminates between damaged and intact membranes, corroborated these data.

  20. Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

    ERIC Educational Resources Information Center

    Keeley, Page

    2013-01-01

    A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

  1. Numerical simulation of salt cementation in the porous rocks adjacent to salt diapirs

    NASA Astrophysics Data System (ADS)

    Allstadt, Raphael; Li, Shiyuan; Marquart, Gabriele; Reuning, Lars; Niederau, Jan

    2015-04-01

    Porosity and permeability are among the most important petrophysical properties of reservoirs rocks in oil systems. Observations during exploration indicate that in the vicinity of salt domes the porosity of reservoir rocks is often reduced by halite cementation. In this study we present results of simulating the process of salt precipitation near salt diapirs by using a schematic model of a Zechstein diapir in the North Sea basin. The numerical simulation is based on solving the transport equations for heat, porous flow and dispersive and reactive chemical species. Chemical reaction and equilibrium is based on the PHREEQC computer code. In our model over-pressured brine is entering from below and is deflected towards the diapir due to an intermediate layer of low permeability. The high thermal conductivity of salt yields a lateral temperature gradient starting from the diapir. Due to this effect the simulated temperature profile shows lower temperatures close to the salt dome than in comparable depths further away. Caused by the temperature-controlled solubility of NaCl in the brine and supplied ions by the diapir, halite first precipitates near the salt diapir by cementing the pore spaces and thus reducing the porosity. Salt-precipitation in the simulation starts after 840 000 years and reduces the porosity from 10 % to 5.5 % after 19 Mill. years. The permanent influx of brine causes growth of the cementation area and the related reduction of porosity in the reservoir.

  2. Radiation defects and energy storage in natural polycrystalline rock salt. Results of an in-situ test in the Permian rock salt of the Asse

    SciTech Connect

    Gies, H.; Rothfuchs, T.; Celma, A.G.; Haas, J.B.M. de; Pederson, L.

    1994-12-31

    Radiation damage development and the corresponding energy storage in pure undeformed single crystals have frequently been studied in laboratory experiments, however little is known of irradiation experiments on natural rock salt (polycrystalline, deformed and impure) under geological conditions. The relevance of these parameters to the defect formation was revealed by a joint United States/Federal Republic of Germany in-situ test in the Asse Mine. Natural rock salt was heated and irradiated using Co-60 sources. Calculations of the amount of halite expected to be decomposed by radiolysis during the experiment were performed using the 1985 version of the Jain-Lidiard model. Qualitative agreement between theory and analyses was found for all the performed analyses. Quantitative and qualitative deviations of the natural samples behaviour from that of single undeformed crystals were observed and attributed to the influence of sulfatic admixtures, polycrystallinity and strain on radiation damage development and anneal. Special chemical methods, such as iodometric titration and uv-visible spectroscopy were applied in order to measure the hypochlorite ion, which forms in irradiated salt. Composite samples located closet to the Co-60 source averaged 0,4 micromoles neutral chlorine atoms per gram salt, a factor of two more than from other positions. Uv-vis analyses revealed more than a factor of ten greater neutral chlorine concentrations in coloured halite. Similarly, optical absorption measurements indicated a factor of ten difference in sodium metal colloid concentrations.

  3. Discontinuous behavior near excavations in a bedded salt formation

    SciTech Connect

    Stormont, J.C.

    1990-10-01

    Discontinuous behavior is being observed and measured in the vicinity of excavations constructed in a bedded salt formation 650 m below ground surface for the Waste Isolation Pilot Plant (WIPP) Facility. The 2 m thick salt layer in the immediate roof acts as a beam, shearing along a thin overlying anhydrite/clay seam. The floor of the excavations is comprised of a 1 m thick salt layer underlain by a 1 m thick predominately anhydrite layer (referred to as MB139). In the ribs, there is limited fracturing within the first meter of most larger excavations. Vertical fractures develop in pillars at most intersections. The discontinuous behavior is qualitatively consistent with analyses of the formation behaving as a layered medium (elastic beam analysis) and limited tensile and compressive failure of the rock salt. The significance of the discontinuous behavior is that can dominate the effective fluid transport properties of the formation near the excavation, and therefore requires considerations in the design of repository seals. Furthermore, the discontinuous behavior must be monitored and is a very important consideration in the maintenance program designed to assume a safe underground environment. 22 refs., 17 figs.

  4. Geohydromechanical Processes in the Excavation Damaged Zone in Crystalline Rock, Rock Salt, and Indurated and Plastic Clays

    SciTech Connect

    Tsang, Chin-Fu; Bernier, Frederic; Davies, Christophe

    2004-06-20

    The creation of an excavation disturbed zone or excavation damaged zone is expected around all man-made openings in geologic formations. Macro- and micro-fracturing, and in general a redistribution of in situ stresses and rearrangement of rock structures, will occur in this zone, resulting in drastic changes of permeability to flow, mainly through the fractures and cracks induced by excavation. Such an EDZ may have significant implications for the operation and long-term performance of an underground nuclear waste repository. Various issues of concern need to be evaluated, such as processes creating fractures in the excavation damaged zone, the degree of permeability increase, and the potential for sealing or healing (with permeability reduction) in the zone. In recent years, efforts along these lines have been made for a potential repository in four rock types-crystalline rock, salt, indurated clay, and plastic clay-and these efforts have involved field, laboratory, and theoretical studies. The present work involves a synthesis of the ideas and issues that emerged from presentations and discussions on EDZ in these four rock types at a CLUSTER Conference and Workshop held in Luxembourg in November, 2003. First, definitions of excavation disturbed and excavation damaged zones are proposed. Then, an approach is suggested for the synthesis and intercomparison of geohydromechanical processes in the EDZ for the four rock types (crystalline rock, salt, indurated clay, and plastic clay). Comparison tables of relevant processes, associated factors, and modeling and testing techniques are developed. A discussion of the general state-of-the-art and outstanding issues are also presented. A substantial bibliography of relevant papers on the subject is supplied at the end of the paper.

  5. Deformation of underground deep cavities in rock salts at their long-term operations

    SciTech Connect

    Zhuravleva, T.; Shafarenko, E.

    1995-12-01

    The underground deep cavities are created in rock salts of various morphological types with the purpose of storage of petroleum, gas and nuclear wastes. It is well known that the rock salt has rheological properties, which can result in closure of caverns and loss of their stability. In the evaporitic rocks, especially those containing halite, time-dependent deformation is pronounced even at comparatively low stress levels. At high stress levels this creep becomes a dominant feature of the mechanical behavior of salt rocks. So the knowledge of creep behavior of rock salt is of paramount importance in underground storage application of gas, petroleum products and nuclear wastes.

  6. Rock bolt certification tests in salt, Eddy County, New Mexico

    SciTech Connect

    Stewart, R.M.

    1981-11-01

    One hundred rock bolts were installed and tested in the Kerr-McGee potash mine near Carlsbad, New Mexico. The bolts were installed in salt, then instrumented and loaded to failure. The failure modes for tensile tests were expansion shell slippage in salt or polyester resin slippage in salt. The failure modes for shear tests were a combination of bending and shearing or breaking of the bolts near the shear plate-salt interface. Safety factors are not included in the bolt loads in the report. Grade 75 (75,000 psi yield strength) rock bolts with 5/8- and 3/4-in. diameters were stressed into the yield region during tensile and shear tests with 1-3/8-in.-diam by 3-in. expansion shells. The theoretical yield load was 17,000 lb for 5/8-in. bolts and 25,000 lb for 3/4-in. bolts. One-inch-diameter bolts could not be adequately anchored with a single expansion shell to provide yielding. The average anchorage for all bolts moved 1.38 in. before reaching a maximum load of 27,000 lb. Grade 60 (60,000 psi yield strength) deformed reinforcing bar bolts, 1-in. diameter were stressed into the computed yield region approximately 47,000 lb during tensile tests. Yielding was accomplished with polyester resin anchorage when 2 or more resin cartridges (1-1/4 in. by 12 in.) were used. In shear tests, Grade 60 threaded rebar bolts, 1-in. diam, anchored with polyester resin, bent and broke at an average shear force of 34,200 lb with a displacement of 0.52 in.

  7. Thermal expansion of rock-salt cubic AlN

    NASA Astrophysics Data System (ADS)

    Bartosik, M.; Todt, M.; Holec, D.; Todt, J.; Zhou, L.; Riedl, H.; Böhm, H. J.; Rammerstorfer, F. G.; Mayrhofer, P. H.

    2015-08-01

    We combine continuum mechanics modeling and wafer curvature experiments to characterize the thermal expansion coefficient of AlN in its metastable cubic rock-salt (B1) structure. The latter was stabilized as nm thin layers by coherency strains in CrN/AlN epitaxial multilayers deposited on Si (100) substrates using reactive magnetron sputtering. The extraction of the B1-AlN thermal expansion coefficient, from experimentally recorded temperature dependent wafer curvature data, is formulated as an inverse problem using continuum mechanics modeling. The results are cross-validated by density functional theory calculations.

  8. Experimental research on thermal damage of Yingcheng Mine rock salt with ultrasonic wave testing

    NASA Astrophysics Data System (ADS)

    Chen, J.; Tang, H.; Yang, C.

    2009-12-01

    Because of the special mechanical properties (creep behavior, damage and healing, low permeability), rock salt formation can be used for the high level radioactive waste disposal, and the thermal damage property of rock salt is important issue for the stability and sealing of the cavern. For investigation of the thermal damage characteristic of Yingcheng Mine rock salt (Hubei Provence, P.R. China), a series of ultrasonic wave velocity testing during rising temperature (without confining pressure, 20-270 centigrade) were carried out. From the experimental data,the ultrasonic wave velocity, the dynamical modulus (Young's modulus, shear modulus and bulk modulus ) and the dynamical Poisson's (calculated from the ultrasonic wave velocity) ratio decrease during rising temperature. The relationship of the ultrasonic wave velocity and the dynamical modulus between temperature can be expressed by exponential functions. Experimental phenomenon and the ultrasonic wave velocity, especially the spectrum analysis reveals that the thermal damage evolves with the temperature. But there is no phenomena indicates the “critical temperature” and damage self-healing due to the temperature.

  9. Pure water injection into porous rock with superheated steam and salt in a solid state

    NASA Astrophysics Data System (ADS)

    Montegrossi, G.; Tsypkin, G.; Calore, C.

    2012-04-01

    Most of geothermal fields require injection of fluid into the hot rock to maintain pressure and productivity. The presence of solid salt in porous space may cause an unexpected change in the characteristics of the reservoir and produced fluids, and dramatically affect the profitability of the project. We consider an injection problem of pure water into high temperature geothermal reservoir, saturated with superheated vapour and solid salt. Pure water moves away from injection point and dissolves solid salt. When salty water reaches the low-pressure hot domain, water evaporation occurs and, consequently, salt precipitates. We develop a simplified analytical model of the process and derive the similarity solutions for a 1-D semi-infinite reservoir. These solutions are multi-valued and describe the reduction in permeability and porosity due to salt precipitation at the leading boiling front. If the parameters of the system exceed critical values, then similarity solution ceases to exist. We identify this mathematical behaviour with reservoir sealing in the physical system. The TOUGH2-EWASG code has been used to verify this hypothesis and investigate the precipitate formation for an idealized bounded 1-D geothermal system of a length of 500 m with water injection at one extreme and fluid extraction at the other one. Both boundaries are kept at constant pressure and temperature. The result for the semi-infinite numerical model show that the monotonic grow of the solid salt saturation to reach asymptotic similarity solution generally occurs over a very large length starting from the injection point. Reservoir sealing occurs if solid salt at the initial state occupies a considerable part of the porous space. Numerical experiments for the bounded 500 m system demonstrate that a small amount of salt is enough to get reservoir sealing. Generally, salt tend to accumulate near the production well, and salt plug forms at the elements adjacent to the extraction point. This type

  10. Radioactive waste isolation in salt: geochemistry of brine in rock salt in temperature gradients and gamma-radiation fields - a selective annotated bibliography

    SciTech Connect

    Hull, A.B.; Williams, L.B.

    1985-07-01

    Evaluation of the extensive research concerning brine geochemistry and transport is critically important to successful exploitation of a salt formation for isolating high-level radioactive waste. This annotated bibliography has been compiled from documents considered to provide classic background material on the interactions between brine and rock salt, as well as the most important results from more recent research. Each summary elucidates the information or data most pertinent to situations encountered in siting, constructing, and operating a mined repository in salt for high-level radioactive waste. The research topics covered include the basic geology, depositional environment, mineralogy, and structure of evaporite and domal salts, as well as fluid inclusions, brine chemistry, thermal and gamma-radiation effects, radionuclide migration, and thermodynamic properties of salts and brines. 4 figs., 6 tabs.

  11. An ultra-high-energy-neutrino detector using rock salt and ice as detection media for radar method

    SciTech Connect

    Chiba, Masami; Kamijo, Toshio; Tanikawa, Takahiro; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kon, Tadashi; Shimizu, Yutaka; Utsumi, Michiaki; Fujii, Masatoshi

    2012-11-12

    We had found radio-wave-reflection effect in rock salt for detection of an ultra-high energy neutrino (UHE{nu}) which is generated in GZK processes in the universe. When an UHE{nu} interacts with rock salt or ice as a detection medium, the energy converts to a thermal energy. Consequently, a temperature gives rise along an UHE{nu} shower at the interaction location. The permittivity arises with respect to the temperature at ionization processes of the UHE{nu} shower which is composed of hadronic and electromagnetic multiplication processes. The irregularity of the refractive index in the medium for radio wave rises to a reflection. The reflection effect with a long attenuation length of radio wave in rock salt and ice would yield a new method to detect UHE{nu}. They could be used for detection media in which the UHE{nu} interacts with. We could find a huge amount of rock salt or ice over 50 Gt in a natural rock salt formation or Antarctic ice sheet. Radio wave transmitted into the medium generated by a radar system could be reflected by the irregularity of the refractive index at the shower. Receiving the reflected radio wave yields information about the UHE{nu}.

  12. Effect of Dihedral Angle and Porosity on Percolating-Sealing Capacity of Texturally Equilibrated Rock Salt

    NASA Astrophysics Data System (ADS)

    Ghanbarzadeh, S.; Hesse, M. A.; Prodanovic, M.; Gardner, J. E.

    2013-12-01

    Salt deposits in sedimentary basins have long been considered to be a seal against fluid penetration. However, experimental, theoretical and field evidence suggests brine (and oil) can wet salt crystal surfaces at higher pressures and temperatures, which can form a percolating network. This network may act as flow conduits even at low porosities. The aim of this work is to investigate the effects of dihedral angle and porosity on the formation of percolating paths in different salt network lattices. However, previous studies considered only simple homogeneous and isotropic geometries. This work extends the analysis to realistic salt textures by presenting a novel numerical method to describe the texturally equilibrated pore shapes in polycrystalline rock salt and brine systems. First, a theoretical interfacial topology was formulated to minimize the interfacial surface between brine and salt. Then, the resulting nonlinear system of ordinary differential equations was solved using the Newton-Raphson method. Results show that the formation of connected fluid channels is more probable in lower dihedral angles and at higher porosities. The connectivity of the pore network is hysteretic, because the connection and disconnection at the pore throats for processes with increasing or decreasing porosities occur at different porosities. In porous media with anisotropic solids, pores initially connect in the direction of the shorter crystal axis and only at much higher porosities in the other directions. Consequently, even an infinitesimal elongation of the crystal shape can give rise to very strong anisotropy in permeability of the pore network. Also, fluid flow was simulated in the resulting pore network to calculate permeability, capillary entry pressure and velocity field. This work enabled us to investigate the opening of pore space and sealing capacity of rock salts. The obtained pore geometries determine a wide range of petrophysical properties such as permeability and

  13. Thermal properties of rock salt and quartz monzonite to 573{sup 0}K and 50-MPa confining pressure

    SciTech Connect

    Durham, W.B.; Abey, A.E.

    1981-03-18

    Measurements of thermal conductivity, thermal diffusivity, and thermal linear expansion have been made on two rock types, a rock salt and a quartz monzonite, at temperatures from 300 to 573{sup 0}K and confining pressures from 10 to 50 MPa. The samples were taken from deep rock formations under consideration as possible sites for a nuclear waste repository - the rock salt from a domal salt formation at Avery Island, Louisiana, and the quartz monzonite from the Climax Stock, Nevada Test Site, Nevada. The testing temperature and pressures are meant to bracket conditions expected in the repository. In both rock types, the thermal properties show a strong dependence upon temperature and a weak or non-dependence upon confining pressure. Thermal conductivity and diffusivity both decrease with increasing temperature in approximately linear fashion for samples which have not been previously heated. At 50 MPa in both rocks this decrease closely matches the measured or expected intrinsic (crack-free) behavior of the material. Preliminary indications from the quartz monzonite suggest that conductivity and diffusivity at low pressure and temperature may decrease as a result of heat treatment above 400{sup 0}K.

  14. Accelerator Measurments of the Askaryan Effect in Rock Salt: A Roadmap Toward Teraton Underground Neutrino Detectors

    SciTech Connect

    Gorham, P.

    2004-12-15

    We report on further SLAC measurements of the Askaryan effect: coherent radio emission from charge asymmetry in electromagnetic cascades. We used synthetic rock salt as the dielectric medium, with cascades produced by GeV bremsstrahlung photons at the Final Focus Test Beam. We extend our prior discovery measurements to a wider range of parameter space and explore the effect in a dielectric medium of great potential interest to large scale ultra-high energy neutrino detectors: rock salt (halite), which occurs naturally in high purity formations containing in many cases hundreds of cubic km of water-equivalent mass. We observed strong coherent pulsed radio emission over a frequency band from 0.2-15 GHz. A grid of embedded dual-polarization antennas was used to confirm the high degree of linear polarization and track the change of direction of the electric-field vector with azimuth around the shower. Coherence was observed over 4 orders of magnitude of shower energy. The frequency dependence of the radiation was tested over two orders of magnitude of UHF and microwave frequencies. We have also made the first observations of coherent transition radiation from the Askaryan charge excess, and the result agrees well with theoretical predictions. Based on these results we have performed detailed and conservative simulation of a realistic GZK neutrino telescope array within a salt-dome, and we find it capable of detecting 10 or more contained events per year from even the most conservative GZK neutrino models.

  15. Accelerator measurements of the Askaryan effect in rock salt: A roadmap toward teraton underground neutrino detectors

    SciTech Connect

    Gorham, P.W.; Guillian, E.; Milincic, R.; Miocinovic, P.; Saltzberg, D.; Williams, D.; Field, R.C.; Walz, D.

    2005-07-15

    We report on further SLAC measurements of the Askaryan effect: coherent radio emission from charge asymmetry in electromagnetic cascades. We used synthetic rock salt as the dielectric medium, with cascades produced by GeV bremsstrahlung photons at the Final Focus Test Beam. We extend our prior discovery measurements to a wider range of parameter space and explore the effect in a dielectric medium of great potential interest to large-scale ultra-high-energy neutrino detectors: rock salt (halite), which occurs naturally in high purity formations containing in many cases hundreds of km{sup 3} of water-equivalent mass. We observed strong coherent pulsed radio emission over a frequency band from 0.2-15 GHz. A grid of embedded dual-polarization antennas was used to confirm the high degree of linear polarization and track the change of direction of the electric-field vector with azimuth around the shower. Coherence was observed over 4 orders of magnitude of shower energy. The frequency dependence of the radiation was tested over 2 orders of magnitude of UHF and microwave frequencies. We have also made the first observations of coherent transition radiation from the Askaryan charge excess, and the result agrees well with theoretical predictions. Based on these results we have performed a detailed and conservative simulation of a realistic GZK neutrino telescope array within a salt dome, and we find it capable of detecting 10 or more contained events per year from even the most conservative GZK neutrino models.

  16. Growth stimulation and proteomic studies of halococci from Permo-Triassic rock salt

    NASA Astrophysics Data System (ADS)

    Legat, A.; Gruber, C.; Stan-Lotter, H.

    2003-04-01

    Viable extremely halophilic archaebacteria were isolated from Austrian Permo-Triassic rock salt and identified as Halococcus species. Growth of these isolates was greatly stimulated by addition of sea salts, Alpine rock salt and rock salt from a Permian deposit in Carrickfergus, Northern Ireland (IS). One-dimensional whole cell protein patterns of strains Hcc. salifodinae and Hcc. dombrowskii were different whether cells were grown in the presence or absence of IS, which suggested influences by unknown components in the rock salt on halobacterial metabolism. Studies of the halococcal proteomes by two-dimensional gel electrophoresis (isoelectric focusing and sodium dodecylsulfate polyacrylamide gele electrophoresis) were begun and revealed differences in the fractions of higher and lower molecular weight components.

  17. Evaluation of Five Sedimentary Rocks Other Than Salt for Geologic Repository Siting Purposes

    SciTech Connect

    Croff, A.G.; Lomenick, T.F.; Lowrie, R.S.; Stow, S.H.

    2003-11-15

    The US Department of Energy (DOE), in order to increase the diversity of rock types under consideration by the geologic disposal program, initiated the Sedimary ROck Program (SERP), whose immediate objectiv eis to evaluate five types of secimdnary rock - sandstone, chalk, carbonate rocks (limestone and dolostone), anhydrock, and shale - to determine the potential for siting a geologic repository. The evaluation of these five rock types, together with the ongoing salt studies, effectively results in the consideration of all types of relatively impermeable sedimentary rock for repository purposes. The results of this evaluation are expressed in terms of a ranking of the five rock types with respect to their potential to serve as a geologic repository host rock. This comparative evaluation was conducted on a non-site-specific basis, by use of generic information together with rock evaluation criteria (RECs) derived from the DOE siting guidelines for geologic repositories (CFR 1984). An information base relevant to rock evaluation using these RECs was developed in hydrology, geochemistry, rock characteristics (rock occurrences, thermal response, rock mechanics), natural resources, and rock dissolution. Evaluation against postclosure and preclosure RECs yielded a ranking of the five subject rocks with respect to their potential as repository host rocks. Shale was determined to be the most preferred of the five rock types, with sandstone a distant second, the carbonate rocks and anhydrock a more distant third, and chalk a relatively close fourth.

  18. Infiltration flux distributions in unsaturated rock deposits andtheir potential implications for fractured rock formations

    SciTech Connect

    Tokunaga, Tetsu K.; Olson, Keith R.; Wan, Jiamin

    2004-11-01

    Although water infiltration through unconsolidated rocks and fractured rock formations control flow and transport to groundwater, spatial distributions of flow paths are poorly understood. Infiltration experiments conducted on packs of rocks showed that a well-constrained distribution of fluxes develops despite differences in rock type (angular diabase and sandstone, and subangular serpentinite), rock size (30 to 200mm), and packing (up to 42 rock layers). Fluxes stabilize into a geometric (exponential) distribution that keeps about half of the system depleted of flow, retains a small fraction of high flow regions, and has a characteristic scale determined by the rock size. Modification of a statistical mechanical model shows that gravity-directed, random flowpaths evolve to the observed flux distribution, and that it represents the most probable distribution. Key similarities between infiltration in rock deposits and fractured rock formations indicate that the geometric flow distribution may also apply in the latter systems.

  19. Numerical Simulation on Open Wellbore Shrinkage and Casing Equivalent Stress in Bedded Salt Rock Stratum

    PubMed Central

    Liu, Jianjun

    2013-01-01

    Most salt rock has interbed of mudstone in China. Owing to the enormous difference of mechanical properties between the mudstone interbed and salt rock, the stress-strain and creep behaviors of salt rock are significantly influenced by neighboring mudstone interbed. In order to identify the rules of wellbore shrinkage and casings equivalent stress in bedded salt rock stratum, three-dimensional finite difference models were established. The effects of thickness and elasticity modulus of mudstone interbed on the open wellbore shrinkage and equivalent stress of casing after cementing operation were studied, respectively. The results indicate that the shrinkage of open wellbore and equivalent stress of casings decreases with the increase of mudstone interbed thickness. The increasing of elasticity modulus will reduce the shrinkage of open wellbore and casing equivalent stress. Research results can provide the scientific basis for the design of mud density and casing strength. PMID:24198726

  20. Interactive evolution concept for analyzing a rock salt cavern under cyclic thermo-mechanical loading

    NASA Astrophysics Data System (ADS)

    König, Diethard; Mahmoudi, Elham; Khaledi, Kavan; von Blumenthal, Achim; Schanz, Tom

    2016-04-01

    The excess electricity produced by renewable energy sources available during off-peak periods of consumption can be used e.g. to produce and compress hydrogen or to compress air. Afterwards the pressurized gas is stored in the rock salt cavities. During this process, thermo-mechanical cyclic loading is applied to the rock salt surrounding the cavern. Compared to the operation of conventional storage caverns in rock salt the frequencies of filling and discharging cycles and therefore the thermo-mechanical loading cycles are much higher, e.g. daily or weekly compared to seasonally or yearly. The stress strain behavior of rock salt as well as the deformation behavior and the stability of caverns in rock salt under such loading conditions are unknown. To overcome this, existing experimental studies have to be supplemented by exploring the behavior of rock salt under combined thermo-mechanical cyclic loading. Existing constitutive relations have to be extended to cover degradation of rock salt under thermo-mechanical cyclic loading. At least the complex system of a cavern in rock salt under these loading conditions has to be analyzed by numerical modeling taking into account the uncertainties due to limited access in large depth to investigate material composition and properties. An interactive evolution concept is presented to link the different components of such a study - experimental modeling, constitutive modeling and numerical modeling. A triaxial experimental setup is designed to characterize the cyclic thermo-mechanical behavior of rock salt. The imposed boundary conditions in the experimental setup are assumed to be similar to the stress state obtained from a full-scale numerical simulation. The computational model relies primarily on the governing constitutive model for predicting the behavior of rock salt cavity. Hence, a sophisticated elasto-viscoplastic creep constitutive model is developed to take into account the dilatancy and damage progress, as well as

  1. The influence of salt formation on electrostatic and compression properties of flurbiprofen salts.

    PubMed

    Supuk, Enes; Ghori, Muhammad U; Asare-Addo, Kofi; Laity, Peter R; Panchmatia, Pooja M; Conway, Barbara R

    2013-12-15

    Salt formation is an effective method of improving physicochemical properties of acidic and basic drugs. The selection of a salt form most suitable for drug development requires a well-designed screening strategy to ensure various issues are addressed in the early development stages. Triboelectrification of pharmaceutical powders may cause problems during processing such as segregation of components due to the effects of particle adhesion. However, very little work has been done on the effect of salt formation on triboelectrification properties. In this paper, salts of flurbiprofen were prepared by combining the drug with a selection of closely related amine counter ions. The aim of the work was to investigate the impact of the counter ion on electrostatic charge of the resultant salts to inform the salt selection process. The experimental results show the magnitude of charge and polarity of the flurbiprofen salts to be highly dependent on the type of counter ion selected for the salt formation. Furthermore, particle adhesion to the stainless steel surface of the shaking container and the salts' compression properties were measured. The formed salts had lower electrostatic charges, improved tabletability, and resulted in reduced adhesion of these powders compared with the parent drug. PMID:24140338

  2. A New Improved Failure Criterion for Salt Rock Based on Energy Method

    NASA Astrophysics Data System (ADS)

    Hao, T. S.; Liang, W. G.

    2016-05-01

    A non-linear triple shear energy yield criterion for salt rock is presented in this paper. It is the development of the triple shear energy yield criterion, of which the Mohr-Coulomb criterion can be seen as a special case. The main factors affecting the primary strength of salt rock, such as the mean stress and the Lode angle, are considered in the non-linear triple shear energy yield criterion. The non-linear new criterion provides the non-linear change trend of salt strength both in the I 1- J 2 stress space and in the deviatoric plane. Comparative study between the non-linear criterion predictions and experimental results of salt rock shows that the non-linear triple shear energy yield criterion fits quite well with both conventional triaxial test data and the true triaxial test data. For Maha Sarakham salt, the predictive capability of the non-linear triple shear energy yield criterion is clearly better than that of some other criteria used by Sriapai, such as modified Lade criterion, 3-D Hoek, and Brown criterion, Drucker-Prager criterion et al. The availability of the non-linear triple shear energy yield criterion can also be confirmed by comparative analysis between theoretical values and experimental values for non-salt rocks. So the non-linear triple shear energy yield criterion is a general failure criterion for rocks fractured by shear stress.

  3. Microfabrics and 3D grain shape of Gorleben rock salt: Constraints on deformation mechanisms and paleodifferential stress

    NASA Astrophysics Data System (ADS)

    Thiemeyer, Nicolas; Zulauf, Gernold; Mertineit, Michael; Linckens, Jolien; Pusch, Maximilian; Hammer, Jörg

    2016-04-01

    The Permian Knäuel- and Streifensalz formations (z2HS1 and z2HS2) are main constituents of the Gorleben salt dome (Northern Germany) and show different amounts and distributions of anhydrite. The reconstruction of 3D halite grain shape ellipsoids reveals small grain size (3.4 ± 0.6 mm) and heterogeneous grain shapes in both formations, the latter attributed to the polyphase deformation of the rock salt during diapirism. The halite microfabrics of both formations indicate that strain-induced grain boundary migration was active during deformation. Crystal plastic deformation of halite is further documented by lattice bending, subgrain formation and minor subgrain rotation. Evidence for pressure solution of halite has not been found, but cannot be excluded because of the small grain size, the lack of LPO and the low differential stress (1.1-1.3 MPa) as deduced from subgrain-size piezometry. Anhydrite has been deformed in the brittle-ductile regime by solution precipitation creep, minor dislocation creep and brittle boudinage. No continuous anhydrite layers are preserved, and halite has acted as a sealing matrix embedding the disrupted anhydrite fragments prohibiting any potential migration pathways for fluids. Thus, anhydrite should not have a negative effect on the barrier properties of the Gorleben rock salts investigated in this study.

  4. Dissolution of bedded rock salt: A seismic profile across the active eastern margin of the Hutchinson Salt Member, central Kansas

    USGS Publications Warehouse

    Anderson, N.L.; Hopkins, J.; Martinez, A.; Knapp, R.W.; Macfarlane, P.A.; Watney, W.L.; Black, R.

    1994-01-01

    Since late Tertiary, bedded rock salt of the Permian Hutchinson Salt Member has been dissolved more-or-less continuously along its active eastern margin in central Kansas as a result of sustained contact with unconfined, undersaturated groundwater. The associated westward migration of the eastern margin has resulted in surface subsidence and the contemporaneous sedimentation of predominantly valley-filling Quarternary alluvium. In places, these alluvium deposits extend more than 25 km to the east of the present-day edge of the main body of contiguous rock salt. The margin could have receded this distance during the past several million years. From an environmental perspective, the continued leaching of the Hutchinson Salt is a major concern. This predominantly natural dissolution occurs in a broad zone across the central part of the State and adversely affects groundwater and surface-water quality as nonpoint source pollution. Significant surface subsidence occurs as well. Most of these subsidence features have formed gradually; others developed in a more catastrophic manner. The latter in particular pose real threats to roadways, railways, and buried oil and gas pipelines. In an effort to further clarify the process of natural salt dissolution in central Kansas and with the long-term goal of mitigating the adverse environmental affects of such leaching, the Kansas Geological Survey acquired a 4-km seismic profile across the eastern margin of the Hutchinson Salt in the Punkin Center area of central Kansas. The interpretation of these seismic data (and supporting surficial and borehole geologic control) is consistent with several hypotheses regarding the process and mechanisms of dissolution. More specifically these data support the theses that: 1. (1) Dissolution along the active eastern margin of the Hutchinson Salt Member was initiated during late Tertiary. Leaching has resulted in the steady westward migration of the eastern margin, surface subsidence, and the

  5. Textural evidence for origin of salt dome anhydrite cap rocks, Winnfield Dome, Louisiana

    SciTech Connect

    Ulrich, M.R.; Kyle, J.R.; Price, P.E.

    1985-02-01

    Textures within anhydrite cap rock are products of repeated cycles of halie dissolution and residual anhydrite accretion at tops of salt stocks. Quarrying operations at Winnfield dome have exposed extensive portions of the anhydrite cap rock zone. This zone is composed primarily of unoriented, xenoblastic anhydrite crystals in laminae less than 1 mm to several centimeters thick. Laminations are defined by thin, dark sulfide accumulations and pressure solution of anhydrite. Deformed, banded anhydrite clasts are contained locally within laminae. Multiple-laminated, concave downward anhydrite mounds occur along some horizons. They may contain anhydrite breccia fragments or sulfides. Coarsely crystalline salt mounds, containing disseminated idioblastic anhydrite also occur along horizons. Mound morphologies vary from tall and thin to broad and squat; maximum dimensions range from less than 0.5 to about 2.0 m. These moundlike structures are related spatially and genetically. Moundlike structures are believed to form from salt spines along the salt-anhydrite contact. As the spine dissolves through several cycles of dissolution and accretion, a laminated anhydrite mound is preserved; if the spine becomes isolated from dissolution, then a salt inclusion is preserved. Anhydrite beds within the Louann Salt, deformed during diapirism, are preserved as deformed anhydrite clasts. Steeply dipping, bedded anhydrite zones within the salt stock may produce brecciated anhydrite mounds when incorporated into the cap rock. Sulfides record the movement of metalliferous fluids through the salt-anhydrite contact.

  6. Experimental Investigation of Two-Phase Flow in Rock Salt

    SciTech Connect

    Malama, Bwalya; Howard, Clifford L.

    2014-07-01

    This Test Plan describes procedures for conducting laboratory scale flow tests on intact, damaged, crushed, and consolidated crushed salt to measure the capillary pressure and relative permeability functions. The primary focus of the tests will be on samples of bedded geologic salt from the WIPP underground. However, the tests described herein are directly applicable to domal salt. Samples being tested will be confined by a range of triaxial stress states ranging from atmospheric pressure up to those approximating lithostatic. Initially these tests will be conducted at room temperature, but testing procedures and equipment will be evaluated to determine adaptability to conducting similar tests under elevated temperatures.

  7. The Changing Lithosphere: formation of minerals and dissapearance of rocks

    NASA Astrophysics Data System (ADS)

    Vignola, Teresa; Floriano, Michele A.

    2014-05-01

    Earth Science teaching/learning is based on the idea that lithosphere is subject to changes that continuously modify its aspect. In order to demonstrate one of the causes of these changes, simple laboratory experiments have been used for first year high school students allowing simulating the formation of minerals by precipitation from a saturated solution and their solubility due to chemical reaction with acid substances. In the first stage, solubility, saturated and unsaturated solution concepts have been clarified by using sugar candies thatdissolveat different times by putting them in water containing increasing amounts of added sugar. Afterwards, by inspection of data tables, students have verified that different substances have different solubilities at the same temperature. At this point the solubility CuSO4. 5 H2O was considered and students prepared saturated aqueous solutions by adding 31.6 g of the salt in 100 ml of water. On further addition of salt for a total of 40 g, students have verified the presence of an undissolvedresidue that dissolved on heating. The obtained solution was transferred to a crystallization dish. Subsequent cooling and solvent evaporation produced a supersaturated solution where the precipitation process started allowing the formation, in 5-6 days, of CuSO4. 5 H2O bluecrystals. One of the minerals that can form by precipitation from a saturated solution is calcite that can originate from precipitation of calcium carbonate saturated solutions or from deposition of marine organisms inorganic residues containing calcium carbonate in their shells. However, when a mineral is formed, it will not remain unchanged forever. In order to show that some minerals and carbonaterocks, in addition to erosion phenomena, may also be subject to chemical attacks by atmospheric agents leading to their dissolution. Several rock samples were treated with an acid solution, and the bubbles forming in some of the samples demonstrated that even rocks could

  8. Evidence for episodic basin dewatering in salt-dome cap rocks

    SciTech Connect

    Hallager, W.S. ); Ulrich, M.R. ); Kyle, J.R.; Gose, W.A. ); Price, P.E. )

    1990-08-01

    A detailed record of episodic basin-dewatering events is preserved in the anhydrite cap rocks to two Gulf Coast salt domes. Metal rich brines were intermittently expelled geopressured zones deep in the stratigraphic section and were channeled upward along escape structures bounding the salt diapirs. Overhanging anhydrite cap rock helped to focus some escaping fluid into the zone of dissolution between the top of salt and overlying residual anhydrite cap rock. Iron, lead, and zinc sulfide solubilities were exceeded in this zone, possibly in response to dissolution and reduction of cap-rock sulfates. Because the metalliferous brines entered the dissolution zone intermittently, they were recorded as relatively thin horizontal bands of sulfide sandwiched between thicker accumulations of anhydrite. Continued dissolution of salt and underplating of residual anhydrite caused the sulfide bands to be displaced upward relative to the base of the cap, leading to an inverted stratigraphic record of basin-dewatering events. Paleomagnetic data from the Winnfield salt dome suggest the sulfide-producing basin-dewatering events and anhydrite cap-rock accumulation occurred between 157 and 145 Ma.

  9. Vacancy Structures and Melting Behavior in Rock-Salt GeSbTe

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Wang, Xue-Peng; Shen, Zhen-Ju; Li, Xian-Bin; Wang, Chuan-Shou; Chen, Yong-Jin; Li, Ji-Xue; Zhang, Jin-Xing; Zhang, Ze; Zhang, Sheng-Bai; Han, Xiao-Dong

    2016-05-01

    Ge-Sb-Te alloys have been widely used in optical/electrical memory storage. Because of the extremely fast crystalline-amorphous transition, they are also expected to play a vital role in next generation nonvolatile microelectronic memory devices. However, the distribution and structural properties of vacancies have been one of the key issues in determining the speed of melting (or amorphization), phase-stability, and heat-dissipation of rock-salt GeSbTe, which is crucial for its technological breakthrough in memory devices. Using spherical aberration-aberration corrected scanning transmission electron microscopy and atomic scale energy-dispersive X-ray mapping, we observe a new rock-salt structure with high-degree vacancy ordering (or layered-like ordering) at an elevated temperature, which is a result of phase transition from the rock-salt phase with randomly distributed vacancies. First-principles calculations reveal that the phase transition is an energetically favored process. Moreover, molecular dynamics studies suggest that the melting of the cubic rock-salt phases is initiated at the vacancies, which propagate to nearby regions. The observation of multi-rock-salt phases suggests another route for multi-level data storage using GeSbTe.

  10. Vacancy structures and melting behavior in rock-salt GeSbTe

    DOE PAGESBeta

    Zhang, Bin; Wang, Xue -Peng; Shen, Zhen -Ju; Li, Xian -Bin; Wang, Chuan -Shou; Chen, Yong -Jin; Li, Ji -Xue; Zhang, Jin -Xing; Zhang, Ze; Zhang, Sheng -Bai; et al

    2016-05-03

    Ge-Sb-Te alloys have been widely used in optical/electrical memory storage. Because of the extremely fast crystalline-amorphous transition, they are also expected to play a vital role in next generation nonvolatile microelectronic memory devices. However, the distribution and structural properties of vacancies have been one of the key issues in determining the speed of melting (or amorphization), phase-stability, and heat-dissipation of rock-salt GeSbTe, which is crucial for its technological breakthrough in memory devices. Using spherical aberration-aberration corrected scanning transmission electron microscopy and atomic scale energy-dispersive X-ray mapping, we observe a new rock-salt structure with high-degree vacancy ordering (or layered-like ordering) atmore » an elevated temperature, which is a result of phase transition from the rock-salt phase with randomly distributed vacancies. First-principles calculations reveal that the phase transition is an energetically favored process. Furthermore, molecular dynamics studies suggest that the melting of the cubic rock-salt phases is initiated at the vacancies, which propagate to nearby regions. The observation of multi-rock-salt phases suggests another route for multi-level data storage using GeSbTe.« less

  11. Vacancy Structures and Melting Behavior in Rock-Salt GeSbTe.

    PubMed

    Zhang, Bin; Wang, Xue-Peng; Shen, Zhen-Ju; Li, Xian-Bin; Wang, Chuan-Shou; Chen, Yong-Jin; Li, Ji-Xue; Zhang, Jin-Xing; Zhang, Ze; Zhang, Sheng-Bai; Han, Xiao-Dong

    2016-01-01

    Ge-Sb-Te alloys have been widely used in optical/electrical memory storage. Because of the extremely fast crystalline-amorphous transition, they are also expected to play a vital role in next generation nonvolatile microelectronic memory devices. However, the distribution and structural properties of vacancies have been one of the key issues in determining the speed of melting (or amorphization), phase-stability, and heat-dissipation of rock-salt GeSbTe, which is crucial for its technological breakthrough in memory devices. Using spherical aberration-aberration corrected scanning transmission electron microscopy and atomic scale energy-dispersive X-ray mapping, we observe a new rock-salt structure with high-degree vacancy ordering (or layered-like ordering) at an elevated temperature, which is a result of phase transition from the rock-salt phase with randomly distributed vacancies. First-principles calculations reveal that the phase transition is an energetically favored process. Moreover, molecular dynamics studies suggest that the melting of the cubic rock-salt phases is initiated at the vacancies, which propagate to nearby regions. The observation of multi-rock-salt phases suggests another route for multi-level data storage using GeSbTe. PMID:27140674

  12. Vacancy Structures and Melting Behavior in Rock-Salt GeSbTe

    PubMed Central

    Zhang, Bin; Wang, Xue-Peng; Shen, Zhen-Ju; Li, Xian-Bin; Wang, Chuan-Shou; Chen, Yong-Jin; Li, Ji-Xue; Zhang, Jin-Xing; Zhang, Ze; Zhang, Sheng-Bai; Han, Xiao-Dong

    2016-01-01

    Ge-Sb-Te alloys have been widely used in optical/electrical memory storage. Because of the extremely fast crystalline-amorphous transition, they are also expected to play a vital role in next generation nonvolatile microelectronic memory devices. However, the distribution and structural properties of vacancies have been one of the key issues in determining the speed of melting (or amorphization), phase-stability, and heat-dissipation of rock-salt GeSbTe, which is crucial for its technological breakthrough in memory devices. Using spherical aberration-aberration corrected scanning transmission electron microscopy and atomic scale energy-dispersive X-ray mapping, we observe a new rock-salt structure with high-degree vacancy ordering (or layered-like ordering) at an elevated temperature, which is a result of phase transition from the rock-salt phase with randomly distributed vacancies. First-principles calculations reveal that the phase transition is an energetically favored process. Moreover, molecular dynamics studies suggest that the melting of the cubic rock-salt phases is initiated at the vacancies, which propagate to nearby regions. The observation of multi-rock-salt phases suggests another route for multi-level data storage using GeSbTe. PMID:27140674

  13. The effect of hydrocarbons on the microstructural evolution in rock salt: a case study on hydrocarbon bearing Ara salt from the South Oman Salt Basin

    NASA Astrophysics Data System (ADS)

    Schmatz, Joyce; Urai, Janos L.; Wübbeler, Franziska M. M.; Sadler, Marc

    2014-05-01

    It has been shown that dilatant deformation promotes the incorporation of hydrocarbons into typically low permeable rock salt (Schoenherr et al., 2007). However, there is not much knowledge on subsequent mechanisms related to recrystallization processes, which cause morphological and chemical changes of the carbonic inclusions. This work aims to contribute to an increased understanding of fluid inclusion dynamics related to grain boundary migration recrystallization and hence to facilitate the interpretation of complex microstructures in recrystallized, multiphase salt rocks. In this case study we investigate hydrocarbon-impregnated salt from the Cambrian Ara Group in the South Oman Salt Basin. The samples were cored from cm-m thick anhydrite-salt sequences overlying hydrocarbon bearing carbonate stringers in 3300 m depth. The anhydrite layers consist mainly of fine-grained anhydrite, which contains calcite, dolomite, and olivine inclusions. Solid bitumen and lighter hydrocarbon phases are observed in between the anhydrite grains and along cracks. Anhydrite layers host salt veins, which contain fragments of anhydrite. These fragments do not differ in composition or structure from the host material and the related vein microstructures indicate crack-seal mechanisms. Halite in the salt layers is almost entirely recrystallized with solid inclusions consisting of anhydrite, calcite, dolomite and olivine with hydrocarbon-coatings present inside grains and along grain boundaries. Solid inclusions cause pinning indicated by a decreased recrystallized grain size and by the presence of grains with preserved substructures representing earlier deformation phases. We observe two types of carbonic inclusions: I) solid bitumen coatings along grain boundaries and microcracks, interpreted to be incorporated into the salt in an overpressure state that allowed dilatancy of the salt, and II) less degraded, liquid hydrocarbons along grain boundaries in the vicinity of the anhydrite

  14. Biogeomorphically driven salt pan formation in Sarcocornia-dominated salt-marshes

    NASA Astrophysics Data System (ADS)

    Escapa, Mauricio; Perillo, Gerardo M. E.; Iribarne, Oscar

    2015-01-01

    Salt-marshes are under increasing threat, particularly from sea-level rise and increased wave action associated with climate change. The development and stability of these valuable habitats largely depend on complex interactions between biotic and abiotic processes operating at different scales. Also, interactions between biotic and abiotic processes drive internal morphological change in salt-marshes. In this paper we used a biogeomorphological approach to assess the impact of biological activities and interactions on salt pan formation in Sarcocornia-dominated salt marshes. Salt pans represent a key physiographic feature of salt-marshes and recent studies hypothesized that biogeomorphic processes could be related to salt pan formation in SW Atlantic salt-marshes. The glasswort Sarcocornia perennis is one of the dominant plants in the salt-marshes of the Bahía Blanca Estuary (Argentina) where they form patches up to 8 m in diameter. These salt-marshes are also inhabited in great densities by the burrowing crab Neohelice (Chasmagnathus) granulata whose bioturbation rates are among the highest reported for salt-marshes worldwide. A set of biological interactions between N. granulata and S. perennis appears to be responsible for salt pan development in these areas which has not been described elsewhere. The main objective of this work was to determine the ecological interactions occurring between plants and crabs that lead to salt pan formation by using field-based sampling and manipulative experiments. Our results showed that S. perennis facilitated crab colonization of the salt-marsh by buffering otherwise stressful physical conditions (e.g., temperature, desiccation). Crabs preferred to construct burrows underneath plants and, once they reach high densities (up to 40 burrows m- 2), the sediment reworking caused plant die-off in the central area of patches. At this state, the patches lose elevation and become depressed due to the continuous bioturbation by crabs

  15. Formation of alkylaminium salts in particulate matter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amines in the atmosphere derive from sources, such as sewage treatment and livestock feeding. The abundance of these amines in the atmosphere makes it important to determine how amines react to form particles, specifically amine salts. Experiments were conducted in a smog chamber to determine the ch...

  16. Formation of alkylaminium salts in particulate matter.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Smog chamber experiments were conducted to determine how amines react to form particles, specifically amine salts, in the atmosphere. All of the experiments were performed in a smog chamber at University of California Riverside’s College of Engineering Center for Environmental Research and Technolo...

  17. Tests of US rock salt for long-term stability of CAES reservoirs

    SciTech Connect

    Gehle, R.M.; Thoms, R.L.

    1986-01-01

    This is a report on laboratory tests to assess the effects of compressed air energy storage (CAES) on rock salt within the US. The project included a conventional laboratory test phase, with triaxial test machines, and a bench-scale test phase performed in salt mines in southern Louisiana. Limited numerical modeling also was performed to serve as a guide in selecting test layouts and for interpreting test data.

  18. Halophilic Archaea Cultivated from Surface Sterilized Middle-Late Eocene Rock Salt Are Polyploid

    PubMed Central

    Jaakkola, Salla T.; Zerulla, Karolin; Guo, Qinggong; Liu, Ying; Ma, Hongling; Yang, Chunhe; Bamford, Dennis H.; Chen, Xiangdong; Soppa, Jörg; Oksanen, Hanna M.

    2014-01-01

    Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38–41 million years ago) rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11–14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6–8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment. PMID:25338080

  19. Halophilic archaea cultivated from surface sterilized middle-late eocene rock salt are polyploid.

    PubMed

    Jaakkola, Salla T; Zerulla, Karolin; Guo, Qinggong; Liu, Ying; Ma, Hongling; Yang, Chunhe; Bamford, Dennis H; Chen, Xiangdong; Soppa, Jörg; Oksanen, Hanna M

    2014-01-01

    Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38-41 million years ago) rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11-14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6-8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment. PMID:25338080

  20. Three dimensional finite element simulations of room and pillar mines in rock salt

    SciTech Connect

    Hoffman, E.L.; Ehgartner, B.L.

    1996-05-01

    3-D quasistatic finite element codes are being used at Sandia to simulate large room and pillar mines in rock salt. The two examples presented in this paper are of mines supported by US DOE, under the auspices of the Strategic Petroleum Reserve program. One of the mines is presently used as an oil storage facility. These simulations, validated by field measurements and observations, have provided valuable insight into the failure mechanisms of room and pillar mines in rock salt. The calculations provided the basis for further investigation and the ultimate decision to decommission the DOE oil storage facility.

  1. In situ measurements of rock salt permeability changes due to nearby excavation

    SciTech Connect

    Stormont, J.C. ); Howard, C.L. ); Daemen, J.J.K. . Mackay School of Mines)

    1991-07-01

    The Small-Scale Mine-By was an in situ experiment to measure changes in brine and gas permeability of rock salt as a result of nearby excavation. A series of small-volume pressurized brine- and gas-filled test intervals were established 8 m beneath the floor of Room L1 in the WIPP underground. The test intervals were isolated in the bottom of the 4.8-cm diameter monitoring boreholes with inflatable rubber packers, and are initially pressurized to about 2 MPa. Both brine- and gas-filled test intervals were located 1.25, 1.5, 2, 3, and 4 r from the center of a planned large-diameter hole, where r is the radius of the large-diameter hole. Prior to the drilling of the large-diameter borehole, the responses of both the brine- and gas-filled test intervals were consistent with the formation modeled as a very low permeability, low porosity porous medium with a significant pore (brine) pressure and no measurable gas permeability. The drilling of the mine-by borehole created a zone of dilated, partially saturated rock out to about 1.5 r. The formation pressure increases from near zero at 1.5 r to the pre-excavation value at 4 r. Injection tests reveal a gradient of brine permeabilities from 5 {times} 10{sup {minus}18} m{sup 2} at 1.25 r to about the pre-excavation value (10{sup {minus}21} m{sup 2}) by 3 r. Gas-injection tests reveal measurable gas permeability is limited to within 1.5 r. 17 refs., 24 figs., 6 tabs.

  2. Heavy Metal Contamination and Salt Efflorescence Associated With Decorative Landscaping Rocks, Las Vegas, Nevada: The Need for Regulations

    NASA Astrophysics Data System (ADS)

    Mrozek, S. A.; Buck, B. J.; Brock, A. L.

    2004-12-01

    Las Vegas, Nevada is one of the fastest growing cities in the United States. Faced with water restrictions, decorative rock xeroscaping has become a very popular form of landscaping. Currently, there are no regulations controlling the geochemistry of the decorative rocks that can be used for these purposes. In this study, we examined three sites containing two different decorative rock products. The landscaping rocks, underlying soil, and surface salt crusts were analyzed to determine their mineralogy and chemistry. Methods of analysis include scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP), thin section analysis, and laser particle size analysis (LPSA). Preliminary results indicate the presence of halite (NaCl), bloedite (Na2Mg(SO4)2 4H2O), a hydrated magnesium sulfate, and possibly copper sulfate and copper chloride mineral phases in the surface salt crusts. Both copper minerals are regarded as hazardous substances by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA); these agencies have established minimum exposure limits for human contact with these substances. Copper sulfate and copper chloride are not naturally occurring minerals in the soils of the Las Vegas Valley, and analyses indicate that their formation may be attributed to the mineralogy of the decorative landscaping rocks. Further testing is needed to characterize this potential health hazard; however the preliminary results of this study demonstrate the need for regulations controlling the geochemistry of decorative rocks used for urban landscaping.

  3. Particle formation above natural and simulated salt lakes

    NASA Astrophysics Data System (ADS)

    Kamilli, Katharina; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Zetzsch, Cornelius; Held, Andreas

    2013-04-01

    Western Australia was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Thus, the ground-water level rose and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 1.5 m³ Teflon chamber was set up above several lakes in 2012. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level lead to strongly increased aerosol formation. As salt lakes have been identified as a source for reactive halogen species (RHS; Buxmann et al., 2012) and RHS seem to interact with precursors of secondary organic aerosol (SOA), they could be producers of halogen induced secondary organic aerosol (XOA) (Ofner et al., 2012). As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine XOA formation under atmospheric conditions using simulated sunlight and the chemical composition of a chosen salt lake. After adding α-pinene to the simulated salt lake, a strong nucleation event began in the absence of ozone comparable to the observed events in Western Australia. First results from the laboratory based aerosol smog-chamber experiments indicate a halogen-induced aerosol

  4. Grating formation in diazo salt (sensitized) gelatin.

    PubMed

    Gladden, J W

    1980-05-01

    Diazo (sensitized) gelatins are photosensitive recording materials that, unlike dichromated gelatin, have a long shelf life. Because of their stability, the diazo emulsions have replaced the dichromated colloids used in the photolithographic field and enabled commercialization of presensitized printing plates. We have produced plane wave gratings with peak efficiencies near 67% at an exposure of 625 mJ/cm(2) and a recording wavelength of 488.0 nm in one diazo recording material. Called diazo salt (sensitized) gelatin, the photosensitive material produces gratings in gelatin by a complex process that we found not to be a function of exposure. The methods used are described. PMID:20221070

  5. Impact of rock salt creep law choice on subsidence calculations for hydrocarbon reservoirs overlain by evaporite caprocks

    NASA Astrophysics Data System (ADS)

    Marketos, G.; Spiers, C. J.; Govers, R.

    2016-06-01

    Accurate forward modeling of surface subsidence above producing hydrocarbons reservoirs requires an understanding of the mechanisms determining how ground deformation and subsidence evolve. Here we focus entirely on rock salt, which overlies a large number of reservoirs worldwide, and specifically on the role of creep of rock salt caprocks in response to production-induced differential stresses. We start by discussing available rock salt creep flow laws. We then present the subsidence evolution above an axisymmetric finite element representation of a generic reservoir that extends over a few kilometers and explore the effects of rock salt flow law choice on the subsidence response. We find that if rock salt creep is linear, as appropriate for steady state flow by pressure solution, the subsidence response to any pressure reduction history contains two distinct components, one that leads to the subsidence bowl becoming narrower and deeper and one that leads to subsidence rebound and becomes dominant at later stages. This subsidence rebound becomes inhibited if rock salt deforms purely through steady state power law creep at low stresses. We also show that an approximate representation of transient creep leads to relatively small differences in subsidence predictions. Most importantly, the results confirm that rock salt flow must be modeled accurately if good subsidence predictions are required. However, in practice, large uncertainties exist in the creep behavior of rock salt, especially at low stresses. These are a consequence of the spatial variability of rock salt physical properties, which is practically impossible to constrain. A conclusion therefore is that modelers can only resort to calculating bounds for the subsidence evolution above producing rock salt-capped reservoirs.

  6. Natural gas storage in bedded salt formations

    SciTech Connect

    Macha, G.

    1996-09-01

    In 1990 Western Resources Inc. (WRI) identified the need for additional natural gas storage capacity for its intrastate natural gas system operated in the state of Kansas. Western Resources primary need was identified as peak day deliverability with annual storage balancing a secondary objective. Consequently, an underground bedded salt storage facility, Yaggy Storage Field, was developed and placed in operation in November 1993. The current working capacity of the new field is 2.1 BCF. Seventy individual caverns are in service on the 300 acre site. The caverns vary in size from 310,000 CF to 2,600,000 CF. Additional capacity can be added on the existing acreage by increasing the size of some of the smaller existing caverns by further solution mining and by development of an additional 30 potential well sites on the property.

  7. Modeling of the T S D E Heater Test to Investigate Crushed Salt Reconsolidation and Rock Salt Creep for the Underground Disposal of High-Level Nuclear Waste

    NASA Astrophysics Data System (ADS)

    Blanco Martin, L.; Rutqvist, J.; Birkholzer, J. T.; Wolters, R.; Lux, K. H.

    2014-12-01

    -level nuclear waste in rock salt. References: [1] Bechthold et al., 1999. BAMBUS-I Project. Euratom, Report EUR19124-EN. [2] Blanco Martín et al., 2014. Comparison of two sequential simulators to investigate thermal-hydraulic-mechanical processes related to nuclear waste isolation in saliniferous formations. In preparation.

  8. Mechanics of salt tongue formation with examples from Louisiana Slope

    SciTech Connect

    D'Onfro, P.

    1988-01-01

    Salt tongues up to several thousand feet thick and a few tens of miles long appear to intrude sediments along the Sigsbee Scarp and in the Mississippi fan in the Gulf of Mexico. Because salt tongues are impermeable and cover large areas of sediment, they have the potential to trap tremendous volumes of hydrocarbons. Field observations, laboratory experiments, and in-situ measurements in salt mines indicate that salt behaves like a viscous fluid over geologic time. Consequently, the same mechanical principles used to analyze igneous dike and sill formation can be applied to salt intrusions. Evidence suggests that salt tongues, like igneous sills, intrude sedimentary strata in which both horizontal principal compressive stresses exceed the overburden stress. This stress state exists in areas of regional tectonic or localized horizontal compression (e.g., in active thrust and foldbelts, in the toe regions of active growth fault systems, and around the flanks of intruding diapirs). This model puts constraints on both the timing of emplacement and the location of salt tongues.

  9. Sphalerite-rock salt phase transition in ZnMnSe heterostructures

    SciTech Connect

    Litvinov, D.; Gerthsen, D.; Rosenauer, A.; Daniel, B.; Hetterich, M.

    2004-08-02

    We report on the investigation of epitaxial MnSe layers grown on ZnSe by transmission electron microscopy. MnSe/ZnSe superlattices (SLs) with different nominal MnSe thicknesses t{sub MnSe} between 2 and 20 monolayers (MLs) were investigated, which were grown by molecular-beam epitaxy on GaAs(001) substrates. Composition profiles of the SLs were evaluated by the measurement of local (002) lattice parameters in growth direction. A MnSe deposition between 2 and 4 MLs on ZnSe leads to the formation of intermixed Zn{sub 1-x}Mn{sub x}Se layers with sphalerite structure and a Mn concentration x increasing from 50% to 90%. For MnSe layers with a thickness between 6 and 20 ML, we observe 5-10 nm small MnSe inclusions with a rock salt structure embedded in sphalerite Zn{sub 1-x}Mn{sub x}Se with approximately 90%Mn.

  10. Thermoelastic properties of rock-salt NaCl at high pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Santos, M. L. M.; Shukla, G.; Wentzcovitch, R. M.

    2014-12-01

    Rock-salt NaCl is an important mineral in our daily lives, in high pressure science/technology, and in the oil/gas industry. The latter has come to prominence since the discovery of deep water pre-salt structures containing great hydrocarbon reserves out of the SE coast of Brazil. The unique aspects of these regions, such as deep water (greater than 2 km below sea level) and deep hydrocarbon reserves (more than 5 km deep) are challenging for oil/gas explorations. Oil/gas field imaging algorithms require good velocity models for seismic wave-propagation within the salt layer. Despite its importance, there is still insufficient information on the elasticity of and sound velocities in NaCl at relevant P,T conditions. Here we report such properties in rock-salt NaCl at relevant P,T conditions as obtained by first principles (DFT) quasiharmonic calculations. We compare intermediate and final results with available experimental data on thermodynamics and thermoelastic properties and combine them for optimum accuracy. These results should be useful for and facilitate imaging pre-salt hydrocarbon reserves. Research supported by CAPES from Brazil, NSF/DMR, and NSF/EAR.

  11. Observations regarding the stability of bentonite backfill in a high-level waste (HLW) repository in rock salt

    SciTech Connect

    Krumhansl, J.L.

    1986-01-01

    Consideration of bentonite as a component of the engineered barrier system surrounding high-level nuclear waste (HLW) canisters in rock salt raised several questions regarding the stability of this clay. Dehydration studies pertinent to the period immediately following waste emplacement showed a partial loss in swelling ability, the extent of which depended on the composition of the rehydrating brine and increased with temperature from 150/sup 0/ to 320/sup 0/C. At a later date, hydrothermal reactions between brine and bentonite may occur as pressure in the repository rises and the backfill saturates with brine. In pure sodium chloride brines little change in the bentonite was observed after two months at 250/sup 0/C. In the same amount of time, brines rich in potassium formed mixed-layer, illite-smectite clays. Adding magnesium to the brine arrested mixed-layer clay formation; instead, a magnesium-enriched montmorillonite formed and the brine pH dropped. Radiation stability studies to 10/sup 10/ rads were conducted in both wet and dry environments, but caused no detectable alteration of the clay. In contrast, fluid-phase compositions changed significantly. Gamma irradiation of dry bentonite produced an oxygen-depleted atmosphere which was enriched in both hydrogen and carbon dioxide. Mixed bentonite-brine slurries produced copious amounts of both hydrogen and oxygen gas when irradiated. These irradiated slurries generally had posttest pH values between 4 and 6. Solutions made by exposing preirradiated salt and bentonite to unirradiated water, or brine, had pH values between 6 and 8.5 and, in the case of salt solutions, were highly oxidizing. Although more research is needed for a complete performance assessment, it appears that such backfills may prove useful in a variety of rock-salt environments.

  12. Spinel–rock salt transformation in LiCoMnO4−δ

    PubMed Central

    Reeves-McLaren, Nik; Sharp, Joanne; Beltrán-Mir, Héctor; Rainforth, W. Mark; West, Anthony R.

    2016-01-01

    The transformation on heating LiCoMnO4, with a spinel structure, to LiCoMnO3, with a cation-disordered rock salt structure, accompanied by loss of 25% of the oxygen, has been followed using a combination of diffraction, microscopy and spectroscopy techniques. The transformation does not proceed by a topotactic mechanism, even though the spinel and rock salt phases have a similar, cubic close-packed oxygen sublattice. Instead, the transformation passes through two stages involving, first, precipitation of Li2MnO3, leaving behind a Li-deficient, Co-rich non-stoichiometric spinel and, second, rehomogenization of the two-phase assemblage, accompanied by additional oxygen loss, to give the homogeneous rock salt final product; a combination of electron energy loss spectroscopy and X-ray absorption near edge structure analyses showed oxidation states of Co2+ and Mn3+ in LiCoMnO3. Subsolidus phase diagram determination of the Li2O-CoOx-MnOy system has established the compositional extent of spinel solid solutions at approximately 500°C. PMID:26997883

  13. Disordered lithium niobate rock-salt materials prepared by hydrothermal synthesis.

    PubMed

    Modeshia, Deena R; Walton, Richard I; Mitchell, Martin R; Ashbrook, Sharon E

    2010-07-14

    An investigation of the one-step hydrothermal crystallisation of lithium niobates reveals that reaction between Nb(2)O(5) and aqueous LiOH at 240 degrees C yields materials with a disordered rock-salt structure where the metals are statistically distributed over the cation sites. This contrasts with the well-studied reaction between Nb(2)O(5) and NaOH or KOH that produces ANbO(3) (A = Na, K) perovskites. Powder neutron diffraction shows that materials prepared at short reaction times and lower LiOH concentration (2.5 M) are lithium deficient and have a slight excess of niobium, but that at longer periods of reaction in 5 M LiOH, close to the ideal, stoichiometric Li(0.75)Nb(0.25)O composition is produced. Upon annealing this phase cleanly transforms into the known ordered rock-salt material Li(3)NbO(4), a process we have followed using thermodiffractometry, which indicates that transformation begins at approximately 700 degrees C. Solid-state (93)Nb and (7)Li NMR of the disordered and ordered rock-salt phases shows that both contain single metal sites but there is clear evidence for local disorder in the disordered samples. For the ordered material, NMR parameters derived from experiment are also compared to those calculated using density functional theory and are shown to be in good agreement. PMID:20442945

  14. Effect of simulated sampling disturbance on creep behaviour of rock salt

    NASA Astrophysics Data System (ADS)

    Guessous, Z.; Gill, D. E.; Ladanyi, B.

    1987-10-01

    This article presents the results of an experimental study of creep behaviour of a rock salt under uniaxial compression as a function of prestrain, simulating sampling disturbance. The prestrain was produced by radial compressive loading of the specimens prior to creep testing. The tests were conducted on an artifical salt to avoid excessive scattering of the results. The results obtained from several series of single-stage creep tests show that, at short-term, the creep response of salt is strongly affected by the preloading history of samples. The nature of this effect depends upon the intensity of radial compressive preloading, and its magnitude is a function of the creep stress level. The effect, however, decreases with increasing plastic deformation, indicating that large creep strains may eventually lead to a complete loss of preloading memory.

  15. Sulfidation of rock-salt-type transition metal oxide nanoparticles as an example of a solid state reaction in colloidal nanoparticles.

    PubMed

    Chen, Chih-Jung; Chiang, Ray-Kuang

    2011-01-28

    The sulfidation of colloidal rock-salt-type MO (M = Fe, Mn and Co) nanocrystals was performed in organic solvents using dissolved elemental sulfur at moderate temperatures. The vacancy defects in these rock-salt-type structures clearly promote complete oxide-sulfide conversion. The conversion products were hollow metal sulfide (pyrrhotite (Fe(1-x)S), Co(1-x)S and α-MnS) nanoparticles. These conversions by sulfidation proceed rapidly, making difficult the isolation of intermediates. The sulfidation intermediates, when the supply of sulfur was insufficient, had interesting structures, in which the metal oxide cores were surrounded by metal sulfide shells or had surfaces that were decorated with metal sulfide islands. Based on the above results, a mechanism of surface nucleation, shell formation, and void formation by diffusion processes is proposed. PMID:21140007

  16. Formation of the Gulf of Mexico Salt Basin

    NASA Astrophysics Data System (ADS)

    Norton, I. O.; Van Avendonk, H. J.; Christeson, G. L.; Eddy, D. R.

    2014-12-01

    component is a prerequisite for formation of marginal salt basins like the GOM, Aptian South Atlantic and present-day Red Sea.

  17. A New Elasto-Viscoplastic Damage Model Combined with the Generalized Hoek-Brown Failure Criterion for Bedded Rock Salt and its Application

    NASA Astrophysics Data System (ADS)

    Ma, Lin-jian; Liu, Xin-yu; Fang, Qin; Xu, Hong-fa; Xia, Hui-min; Li, Er-bing; Yang, Shi-gang; Li, Wen-pei

    2013-01-01

    According to the requirement of the West-East Gas Transmission Project in China, the solution-mined cavities located in the Jintan bedded salt formation of Jiangsu province will be utilized for natural gas storage. This task is more challenging than conventional salt dome cavern construction and operation due to the heterogeneous bedding layers of the bedded salt formation. A three-dimensional creep damage constitutive model combined with the generalized Hoek-Brown model is exclusively formulated and validated with a series of strength and creep tests for the bedded rock salt. The viscoplastic model, which takes the coupled creep damage and the failure behavior under various stress states into account, enables both the three creep phases and the deformation induced by vicious damage and plastic flow to be calculated. A further geomechanical analysis of the rapid gas withdrawal for the thin-bedded salt cavern was performed by implementing the proposed model in the finite difference software FLAC3D. The volume convergence, the damage and failure propagation of the cavern, as well as the strain rate of the salt around the cavern, were evaluated and discussed in detail. Finally, based on the simulation study, a 7-MPa minimum internal pressure is suggested to ensure the structural stability of the Jintan bedded salt cavern. The results obtained from these investigations provide the necessary input for the design and construction of the cavern project.

  18. Analysis of Shublik Formation rocks from Mt. Michelson quadrangle, Alaska

    USGS Publications Warehouse

    Detterman, Robert L.

    1970-01-01

    Analysis of 88 samples from the Shublik formation on Fire Creek, Mt. Michelson Quadrangle, Alaska, are presented in tabular form. The results include the determination of elements by semiquantitative spectrographic analysis, phosphate by X-ray fluorescence, carbon dioxide by acid decomposable carbonate, total carbon by induction furnace, carbonate carbon by conversion using the conversion factor of 0.2727 for amount of carbon in carbon dioxide, and organic carbon by difference. A seven- cycle semilogarithmic chart presents the data graphically and illustrates the range, mode, and mean for some of the elements. The chart shows, also, the approximate concentration of the same elements in rocks similar to the black shale and limestone of the Shublik Formation. Each sample represents 5 feet of section and is composed of rock chips taken at 1 - foot intervals. The samples are keyed into a stratigraphic column of the formation. Rocks of the Shublik Formation contain anomalously high concentrations of some of the elements. These same elements might be expected to be high in some of the petroleum from northern Alaska if the Shublik Formation is a source for this petroleum. Several of the stratigraphic intervals may represent, also, a low-grade phosphate deposit.

  19. Particle formation above natural and simulated salt lakes

    NASA Astrophysics Data System (ADS)

    Kamilli, Katharina A.; Ofner, Johannes; Sattler, Tobias; Krause, Torsten; Held, Andreas

    2014-05-01

    Originally, Western Australia was covered with Eucalyptus trees. Large scale deforestation for agricultural purposes led to rising ground water levels and brought dissolved salts and minerals to the surface. Nowadays, Western Australia is known for a great plenty of salt lakes with pH levels reaching from 2.5 to 7.1. The land is mainly used for wheat farming and livestock and becomes drier due to the lack of rain periods. One possible reason could be the formation of ultrafine particles from salt lakes, which increases the number of cloud condensation nuclei, and thus potentially suppresses precipitation. Several field campaigns have been conducted between 2006 and 2011 with car-based and airborne measurements, where new particle formation has been observed and has been related to the Western Australian salt lakes (Junkermann et al., 2009). To identify particle formation directly above the salt lakes, a 2.35 m³ PTFE chamber was set up above several lakes in 2012 and 2013. Inside the chamber, photochemistry may take place whereas mixing through wind or advection of already existing particles is prevented. Salt lakes with a low pH level led to strongly increased aerosol formation. Also, the dependence on meteorological conditions has been examined. To obtain chemical information of the newly formed particles, during the chamber experiments also aerosol filter samples have been taken. The analysis of the anions by ion chromatography in 2012 showed an 8 to 17 times higher concentration of Cl- than SO42-, which led to the assumption that particle formation may have been influenced by halogens. As reference experiments, laboratory based aerosol smog-chamber runs were performed to examine halogen induced aerosol formation under atmospheric conditions using simulated sunlight and the simplified chemical composition of a salt lake. The mixture included FeSO4, NaCl and Na2SO4. After adding α-pinene to the simulated salt lake, a strong nucleation event began comparable to

  20. Geochemical relationships of petroleum in Mesozoic reservoirs to carbonate source rocks of Jurassic Smackover Formation, southwestern Alabama

    SciTech Connect

    Claypool, G.E.; Mancini, E.A.

    1989-07-01

    Algal carbonate mudstones of the Jurassic Smackover Formation are the main source rocks for oil and condensate in Mesozoic reservoir rocks in southwestern Alabama. This interpretation is based on geochemical analyses of oils, condensates, and organic matter in selected samples of shale (Norphlet Formation, Haynesville Formation, Trinity Group, Tuscaloosa Group) and carbonate (Smackover Formation) rocks. Potential and probable oil source rocks are present in the Tuscaloosa Group and Smackover Formation, respectively. Extractable organic matter from Smackover carbonates has molecular and isotopic similarities to Jurassic oil. Although the Jurassic oils and condensates in southwestern Alabama have genetic similarities, they show significant compositional variations due to differences in thermal maturity and organic facies/lithofacies. Organic facies reflect different depositional conditions for source rocks in the various basins. The Mississippi Interior Salt basin was characterized by more continuous marine to hypersaline conditions, whereas the Manila and Conecuh embayments periodically had lower salnity and greater input of clastic debris and terrestrial organic matter. Petroleum and organic matter in Jurassic rocks of southwestern Alabama show a range of thermal transformations. The gas content of hydrocarbons in reservoirs increases with increasing depth and temperature. In some reservoirs where the temperature is above 266/degrees/F(130/degrees/C), gas-condensate is enriched in isotopically heavy sulfur, apparently derived from thermochemical reduction of Jurassic evaporite sulfate. This process also resulted in increase H/sub 2/S and CO in the gas, and depletion of saturated hydrocarbons in the condensate liquids.

  1. A primer on liquid hydrocarbon storage in salt formations

    SciTech Connect

    Halfast, T.G.

    1996-09-01

    Storage caverns leached in both domal and bedded salt formations have been an economical, safe and environmentally sound method of storing large quantities of liquid hydrocarbons since the late 1940`s and today these formations are utilized throughout the world to store many different liquid hydrocarbons. This paper addresses some of the many factors that should be considered in the design and operation of a liquid hydrocarbon storage well. For anyone interested in a more thorough primer the author recommends obtaining copies of either API-RP-1114, Titled ``Leached Underground Storage Design`` or API-RP-1115, Titled ``Operation of Solution Mined Storage.``

  2. Experimental study on asphaltene adsorption onto formation rock: An approach to asphaltene formation damage prevention

    SciTech Connect

    Piro, G.; Barberis Canonica, L.; Galbariggi, G.; Bertero, L.; Carniani, C.

    1995-12-31

    In this paper, through a comparative study on Static vs Dynamic adsorption of asphaltene onto formation rock, it is reported how, for the particular asphaltene/formation rock system here considered, the Dynamic asphaltene adsorption onto formation rock is a continuous phenomenon by which the quantity of adsorbed asphaltene increases continuously. In the authors` opinion this rather remarkable adsorption behavior may contribute to asphaltene formation damage. In the hypothesis that prevention may represent a more economical approach than removal, in this work is also reported a possible prevention approach based on formation rock treatment by means of specific chemicals more apt than asphaltenes to be adsorbed onto rock. As preliminary demonstration, with the aim at assessing qualitatively the potential of their approach, the authors have pre-treated the rock by means of commercially available asphaltene dispersant and flocculation inhibitors. Albeit the chosen additives are not commercialized on the base of their specific adsorption feature, a prevention effect has been effectively found. Experimental set ups and procedures used as a base for a test able to rank chemicals with respect to their asphaltene adsorption inhibitive effects are also reported.

  3. Asphaltene adsorption onto formation rock: An approach to asphaltene formation damage prevention

    SciTech Connect

    Piro, G.; Canonico, L.B.; Galbariggi, G.; Bertero, L.; Carniani, C.

    1996-08-01

    In this paper, through a comparative study on static vs. dynamic adsorption of asphaltene onto formation rock, the authors report how, for the particular asphaltene/formation rock system considered, the dynamic asphaltene adsorption onto formation rock is a continuous phenomenon by which the quantity of adsorbed asphaltene increases continuously. In their opinion, this rather remarkable adsorption behavior may contribute to asphaltene formation damage. In the hypothesis that prevention may represent a more economical approach than removal, they also report a possible prevention approach based on formation rock treatment by means of specific chemicals more apt than asphaltenes to be adsorbed onto rock. As a preliminary demonstration, with the aim of assessing qualitatively the potential of their approach, they have pretreated the rock with commercially available asphaltene dispersant and flocculation inhibitors. Although the chosen additives are not commercialized on the basis of their specific adsorption feature, a modest prevention effect has been found. Experimental set-ups and procedures used as a base for a test to rank chemicals with respect to their asphaltene adsorption inhibitive effects are also reported.

  4. Radiation damage measurements on rock salt and other minerals for waste disposal applications. Quarterly report, January 1, 1980-March 31, 1980

    SciTech Connect

    Swyler, K J; Loman, J M; Teutonico, L J; Elgort, G E; Levy, P W

    1980-04-10

    Different aspects of radiation damage in both synthetic NaCl crystals and various natural rock salt samples as well as granite, basalt and other minerals which will be important for radioactive waste disposal applications are being investigated. The principal means of measuring radiation damage is the determination of F-center concentrations, and the concentration and size of sodium metal colloid particles. Formation of these and other defects during irradiation and the annealing of defects and characterization of other processes occurring after irradiation are being studied as a function of dose rate, total dose, sample temperature during irradiation, strain applied prior to and during irradiation, etc. Measurements are being made on synthetic NaCl and natural rock salt samples from different geological locations, including some potential repository sites. It will be necessary to determine if radiation damage in the minerals from different localities is similar. If non-negligible differences are observed a detailed study must be made for each locality under consideration. Almost all current studies are being made on rock salt but other minerals particularly granite and basalt are being phased into the program. It is now established that radiation damage formation in both natural and synthetic rock salt is strongly dependent on strain. The strain related effects strongly indicate that the damage formation processes and in particular the colloid nucleation processes are related to the strain induced disolcations. A temporary theoretical effort has been started to determine which dislocation related effects are important for radiation damage processes and, most importantly, what dislocation interactions are most likely to create nucleation sites for colloid particles. If these preliminary studies indicate that additional theoretical studies will be useful an effort will be made to have them extended.

  5. Creep Behaviour of Bischofite, Carnallite and Mixed Bischofite-Carnallite Salt Rock

    NASA Astrophysics Data System (ADS)

    De Bresser, J. H. P.; Muhammad, N.; Spiers, C. J.; Peach, C. J.

    2014-12-01

    Some salt deposits contain the valuable magnesium and potassium salts bischofite and carnallite, as well as halite, in the form of pure and mixed layers. During extraction of such salts from the subsurface by solution mining, the material in the undissolved walls will flow into the caverns. In order to accurately predict the flow of wall rock material, feasible production rates and related subsidence, a good understanding of the creep behaviour of bischofite, carnallite and mixed salt rocks under in situ conditions is required. We have conducted conventional triaxial compression tests on polycrystalline bischofite, carnallite and mixed bischofite-carnallite-halite rock samples machined from natural cores. The experiments were carried out at true in situ P-T conditions of 70°C and 40 MPa confining pressure. All experiments consisted of strain rate stepping runs, applying strain rates in the range 10-5 to 10-8 s-1, reaching 2-4% axial strain per step, with individual steps being followed by stress relaxation down to strain rates ~10-9 s-1. Both bischofite and carnallite reached near steady state creep behaviour within each constant strain rate step. Carnallite was found to be 4-5 times stronger than bischofite. For bischofite as well as carnallite, we observed that during stress relaxation, the conventional power law stress exponent n changed from ~5 at 10-5 to ~1 at 10-9 s-1. The absolute strength of both materials remained higher if the relaxation started at a higher stress, i.e. at a faster rate. We interpret this as indicating a difference in microstructure at the initiation of the relaxation, notably a smaller grain size related to dynamical recrystallization during the constant strain rate step. The data thus suggest that there is gradual change in mechanism with decreasing strain rate, from grain size insensitive dislocation creep to grain size sensitive (pressure solution) creep. The mixed bischofite-carnallite-halite salt rock did not approach steady state

  6. Cyclic Loading Effects on the Creep and Dilation of Salt Rock

    NASA Astrophysics Data System (ADS)

    Roberts, Lance A.; Buchholz, Stuart A.; Mellegard, Kirby D.; Düsterloh, Uwe

    2015-11-01

    The Solution Mining Research Institute (SMRI) has embarked on inquiries into the effect cyclic loading might have on salt. This interest stems from the concept of using salt caverns as a storage medium for renewable energy projects such as compressed air energy storage where daily pressure cycles in the cavern are conceivable as opposed to the seasonal cycles that are typical for natural gas storage projects. RESPEC and the Institut für Aufbereitung und Deponietechnik at Clausthal University of Technology jointly executed a rock mechanics laboratory study using both facilities for performing triaxial cyclic loading creep tests on rock salt recovered from the Avery Island Mine in Louisiana, USA. The cyclic triaxial creep tests were performed under various load paths including compression, extension, and compression/extension. The tests were performed under both dilative and nondilative stress regimes. The cyclic compression creep data were compared to static creep tests performed under similar conditions to assess the effect of cycling of the applied stress. Furthermore, the cyclic compression tests were compared to a numerically simulated static creep test at the same stress and temperature conditions to determine if the creep behavior was similar under cyclic loading.

  7. Steady-State Creep of Rock Salt: Improved Approaches for Lab Determination and Modelling

    NASA Astrophysics Data System (ADS)

    Günther, R.-M.; Salzer, K.; Popp, T.; Lüdeling, C.

    2015-11-01

    Actual problems in geotechnical design, e.g., of underground openings for radioactive waste repositories or high-pressure gas storages, require sophisticated constitutive models and consistent parameters for rock salt that facilitate reliable prognosis of stress-dependent deformation and associated damage. Predictions have to comprise the active mining phase with open excavations as well as the long-term development of the backfilled mine or repository. While convergence-induced damage occurs mostly in the vicinity of openings, the long-term behaviour of the backfilled system is dominated by the damage-free steady-state creep. However, because in experiments the time necessary to reach truly stationary creep rates can range from few days to years, depending mainly on temperature and stress, an innovative but simple creep testing approach is suggested to obtain more reliable results: A series of multi-step tests with loading and unloading cycles allows a more reliable estimate of stationary creep rate in a reasonable time. For modelling, we use the advanced strain-hardening approach of Günther-Salzer, which comprehensively describes all relevant deformation properties of rock salt such as creep and damage-induced rock failure within the scope of an unified creep ansatz. The capability of the combination of improved creep testing procedures and accompanied modelling is demonstrated by recalculating multi-step creep tests at different loading and temperature conditions. Thus reliable extrapolations relevant to in-situ creep rates (10^{-9} to 10^{-13} s^{-1}) become possible.

  8. Prebiotic Vesicle Formation and the Necessity of Salts.

    PubMed

    Maurer, Sarah E; Nguyen, Gunarso

    2016-06-01

    Self-assembly is considered one of the driving forces behind abiogenesis and would have been affected by the environmental conditions of early Earth. The formation of membranes is a key step in this process, and unlike large dialkyl membranes of modern cells the first membranes were likely formed from small single-chain amphiphiles, which are environment-sensitive. Fatty acids and their derivatives have been previously characterized in this role without concern for the concentrations of ionic solutes in the suspension. We determined the critical vesicle concentration (CVC) for three single-chain amphiphiles with increasing concentrations of NaCl. All amphiphile species had decreasing CVCs correlated to increasing NaCl concentrations. Decanoic acid and oleic acid were impacted more strongly than monoacylglycerol, likely because of electric shielding of the negatively charged headgroups in the presence of salt. There was no impact on the salt species as 100 mM NaBr, NaCl, and KCl all exhibited the same effect on CVC. This research shows the importance of salt in both the formation of life and in experimental design for aggregation experiments. PMID:26590931

  9. Prebiotic Vesicle Formation and the Necessity of Salts

    NASA Astrophysics Data System (ADS)

    Maurer, Sarah E.; Nguyen, Gunarso

    2016-06-01

    Self-assembly is considered one of the driving forces behind abiogenesis and would have been affected by the environmental conditions of early Earth. The formation of membranes is a key step in this process, and unlike large dialkyl membranes of modern cells the first membranes were likely formed from small single-chain amphiphiles, which are environment-sensitive. Fatty acids and their derivatives have been previously characterized in this role without concern for the concentrations of ionic solutes in the suspension. We determined the critical vesicle concentration (CVC) for three single-chain amphiphiles with increasing concentrations of NaCl. All amphiphile species had decreasing CVCs correlated to increasing NaCl concentrations. Decanoic acid and oleic acid were impacted more strongly than monoacylglycerol, likely because of electric shielding of the negatively charged headgroups in the presence of salt. There was no impact on the salt species as 100 mM NaBr, NaCl, and KCl all exhibited the same effect on CVC. This research shows the importance of salt in both the formation of life and in experimental design for aggregation experiments.

  10. Measurements of radio propagation in rock salt for the detection of high-energy neutrinos

    NASA Astrophysics Data System (ADS)

    Connolly, Amy; Goodhue, Abigail; Miki, Christian; Nichol, Ryan; Saltzberg, David

    2009-02-01

    We present measurements of the transmission of radio/microwave pulses through salt in the Cote Blanche salt mine operated by the North American Salt Company in St. Mary Parish, Louisiana. These results are from data taken in the southwestern region of the 1500 ft (457 m) deep level of the mine on our third and most recent visit to the mine. We transmitted and received a fast, high-power, broadband pulse from within three vertical boreholes that were drilled to depths of 100 ft (30 m) and 200 ft below the 1500 ft level using three different pairs of dipole antennas whose bandwidths span 125-900 MHz. By measuring the relative strength of the received pulses between boreholes with separations of 50 and 169 m, we deduce the attenuation of the signal attributed to the salt medium. We fit the frequency dependence of the attenuation to a power law and find the best fit field attenuation lengths to be 93±7m at 150 MHz, 63±3m at 300 MHz, and 36±2m at 800 MHz. This is the most precise measurement of radio attenuation in a natural salt formation to date. We assess the implications of this measurement for a future neutrino detector in salt.

  11. High temperature thermoelectric properties of rock-salt structure PbS

    DOE PAGESBeta

    Parker, David S.; Singh, David J.

    2013-12-18

    We present an analysis of the high temperature transport properties of rock-salt structure PbS, a sister compound to the better studied lead chalcogenides PbSe and PbTe. In this study, we find thermopower magnitudes exceeding 200 V/K in a wide doping range for temperatures of 800 K and above. Based on these calculations, and an analysis of recent experimental work we find that this material has a potential for high thermoelectric performance. Also, we find favorable mechanical properties, based on an analysis of published data.

  12. Bonding preference of carbon, nitrogen, and oxygen in niobium-based rock-salt structures.

    PubMed

    Miura, Akira; Takei, Takahiro; Kumada, Nobuhiro; Wada, Satoshi; Magome, Eisuke; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2013-09-01

    Carbon, nitrogen, and oxygen are essential components in solid-state materials. However, understanding their preference on the bonding to metals has not been straightforward. Here, niobium carbide, nitride, and oxide with simple rock-salt-based structures were analyzed by first-principles calculations and synchrotron X-ray diffraction. We found that an increase in the atomic number from carbon to oxygen formed fewer and shorter bonds to metals with better hybridization of atomic orbitals. This can provide a simple guiding principle for understanding the bonding and designing carbides, nitrides, oxides, and mixed-anion compounds. PMID:23937352

  13. Forensic Analysis of the May 2014 West Salt Creek Rock Avalanche in Western Colorado

    NASA Astrophysics Data System (ADS)

    Coe, J. A.; Baum, R. L.; Allstadt, K.; Kochevar, B. F.; Schmitt, R. G.; Morgan, M. L.; White, J. L.; Stratton, B. T.; Hayashi, T. A.; Kean, J. W.

    2015-12-01

    The rain-on-snow induced West Salt Creek rock avalanche occurred on May 25, 2014 on the northern flank of Grand Mesa. The avalanche was rare for the contiguous U.S. because of its large size (59 M m3) and high mobility (Length/Height=7.2). To understand the avalanche failure sequence, mechanisms, and mobility, we conducted a forensic analysis using large-scale (1:1000) structural mapping and seismic data. We used high-resolution, Unmanned Aircraft System (UAS) imagery as a base for our field mapping and analyzed seismic data from 22 broadband stations (distances <656 km) and one short-period network. We inverted broadband data to derive a time series of forces that the avalanche exerted on the earth and tracked these forces using curves in the avalanche path. Our results revealed that the rock avalanche was a cascade of landslide events, rather than a single massive failure. The sequence began with a landslide/debris flow that started about 10 hours before the main avalanche. The main avalanche lasted just over 3 minutes and traveled at average velocities ranging from 15 to 36 m/s. For at least two hours after the avalanche ceased movement, a central, hummock-rich, strike-slip bound core continued to move slowly. Following movement of the core, numerous shallow landslides, rock slides, and rock falls created new structures and modified topography. Mobility of the main avalanche and central core were likely enhanced by valley floor material that liquefied from undrained loading by the overriding avalanche. Although the base was likely at least partially liquefied, our mapping indicates that the overriding avalanche internally deformed predominantly by sliding along discrete shear surfaces in material that was nearly dry and had substantial frictional strength. These results indicate that the West Salt Creek avalanche, and probably other long-traveled avalanches, could be modeled as two layers: a liquefied basal layer; and a thicker and stronger overriding layer.

  14. Origin of dolostone reservoir rocks, Smackover Formation (Oxfordian), northeastern Gulf Coast, U. S. A

    SciTech Connect

    Prather, B.E. )

    1992-02-01

    Formation of regionally extensive dolostone reservoir rocks in the Smackover can be understood despite the possible effects of recrystallization. Geochemical and petrographic data suggest that dolomitization took place in (1) seawater-seepage, (2) reflux, (3) near-surface mixed-water, (4) shallow-burial mixed-water, and (5) deeper burial environments, which overlapped in time and space to form a platform-scale' dolostone body composed of a complex mixture of dolomites. Seawater-seepage and reflux dolomitization occurred in the near surface penecontemporaneously with deposition of the Smackover and overlying Haynesville Formations. Dolomitization by seawater seepage occurred within an oolite grainstone sill which separated an intraplatform salt basin from the open sea. Seawater flowed landward through the sill in response to evaporitic drawdown of brines in the isolated intraplatform basin. Isolation of the salt basin occurred during the Oxfordian when the shoreline retreated from the Conecuh embayment. Dolomite located at the top of the Smackover enriched in {sup 18}O suggests additional dolomitization by reflux of hypersaline brines. Reflux occurred as Buckner coastal sabkhas prograded over Smackover oolite grainstone shoreface deposits. Vugs lined with shallow-burial calcite and dolomite cements indicate flushing of the Smackover grainstone aquifer with fresh water. Freshwater intrusion probably occurred following sea level lowstands during the Late Jurassic and Early Cretaceous. Leaching in the proximal portion of the freshwater aquifer produced excellent limestone reservoir rocks in the updip Smackover. Dolomitization in the contemporaneous downdip mixed connate/freshwater zone formed dolostone reservoir rocks with depleted isotopic compositions consistent with a shallow-burial mixed-water origin.

  15. The complete genome of a viable archaeum isolated from 123-million-year-old rock salt.

    PubMed

    Jaakkola, Salla T; Pfeiffer, Friedhelm; Ravantti, Janne J; Guo, Qinggong; Liu, Ying; Chen, Xiangdong; Ma, Hongling; Yang, Chunhe; Oksanen, Hanna M; Bamford, Dennis H

    2016-02-01

    Live microbes have been isolated from rock salt up to Permian age. Only obligatory cellular functions can be performed in halite-buried cells. Consequently, their genomic sequences are likely to remain virtually unchanged. However, the available sequence information from these organisms is scarce and consists of mainly ribosomal 16S sequences. Here, live archaea were isolated from early Cretaceous (∼ 123 million years old) halite from the depth of 2000 m in Qianjiang Depression, Hubei Province, China. The sample was radiologically dated and subjected to rigorous surface sterilization before microbe isolation. The isolates represented a single novel species of Halobacterium, for which we suggest the name Halobacterium hubeiense, type strain Hbt. hubeiense JI20-1. The species was closely related to a Permian (225-280 million years old) isolate, Halobacterium noricense, originating from Alpine rock salt. This study is the first one to publish the complete genome of an organism originating from surface-sterilized ancient halite. In the future, genomic data from halite-buried microbes can become a key factor in understanding the mechanisms by which these organisms are able to survive in harsh conditions deep underground or possibly on other celestial bodies. PMID:26628271

  16. Comparison and Tensorial Formulation of Inelastic Constitutive Models of Salt Rock Behaviour and Efficient Numerical Implementatio

    NASA Astrophysics Data System (ADS)

    Nagel, T.; Böttcher, N.; Görke, U. J.; Kolditz, O.

    2014-12-01

    The design process of geotechnical installations includes the application of numerical simulation tools for safety assessment, dimensioning and long term effectiveness estimations. Underground salt caverns can be used for the storage of natural gas, hydrogen, oil, waste or compressed air. For their design one has to take into account fluctuating internal pressures due to different levels of filling, the stresses imposed by the surrounding rock mass, irregular geometries and possibly heterogeneous material properties [3] in order to estimate long term cavern convergence as well as locally critical wall stresses. Constitutive models applied to rock salt are usually viscoplastic in nature and most often based on a Burgers-type rheological model extended by non-linear viscosity functions and/or plastic friction elements. Besides plastic dilatation, healing and damage are sometimes accounted for as well [2]. The scales of the geotechnical system to be simulated and the laboratory tests from which material parameters are determined are vastly different. The most common material testing modalities to determine material parameters in geoengineering are the uniaxial and the triaxial compression tests. Some constitutive formulations in widespread use are formulated based on equivalent rather than tensorial quantities valid under these specific test conditions and are subsequently applied to heterogeneous underground systems and complex 3D load cases. We show here that this procedure is inappropriate and can lead to erroneous results. We further propose alternative formulations of the constitutive models in question that restore their validity under arbitrary loading conditions. For an efficient numerical simulation, the discussed constitutive models are integrated locally with a Newton-Raphson algorithm that directly provides the algorithmically consistent tangent matrix for the global Newton iteration of the displacement based finite element formulation. Finally, the finite

  17. Effect of crustal heterogeneities and effective rock strength on the formation of HP and UHP rocks.

    NASA Astrophysics Data System (ADS)

    Reuber, Georg; Kaus, Boris; Schmalholz, Stefan; White, Richard

    2015-04-01

    The formation of high pressure and ultra-high pressure rocks has been controversially discussed in recent years. Most existing petrological interpretations assume that pressure in the Earth is lithostatic and therefore HP and UHP rocks have to come from great depth, which usually involves going down a subduction channel and being exhumed again. Yet, an alternative explanation points out that pressure in the lithosphere is often non-lithostatic and can be either smaller or larger than lithostatic as a function of location and time. Whether this effect is tectonically significant or not depends on the magnitude of non-lithostatic pressure, and as a result a number of researchers have recently performed numerical simulations to address this. Somewhat disturbingly, they obtained widely differing results with some claiming that overpressures as large as a GPa can occur (Schmalholz et al. 2014), whereas others show that overpressures of exhumed rocks are generally less than 20% and thus insignificant (Li et al. 2010; Burov et al. 2014). In order to understand where these discrepancies come from, we reproduce the simulations of Li et al (2010) of a typical subduction and collision scenario, using an independently developed numerical code (MVEP2). For the same model setup and parameters, we confirm the earlier results of Li et al. (2010) and obtain no more than ~20% overpressure in exhumed rocks of the subduction channel. Yet, a critical assumption in their models is that the subducted crust is laterally homogeneous and that it has a low effective friction angle that is less than 7o. The friction angle of (dry) rocks is experimentally well-constrained to be around 30o, and low effective friction angles require, for example, high-fluid pressures. Whereas high fluid pressures might exist in the sediment-rich upper crust, they are likely to be much lower or absent in the lower crust from which melt has been extracted or in rocks that underwent a previous orogenic cycle. In a

  18. Morphology and dynamics of explosive vents through cohesive rock formations

    NASA Astrophysics Data System (ADS)

    Galland, Olivier; Gisler, Galen R.; Haug, Øystein T.

    2015-04-01

    Shallow explosive volcanic processes, such as kimberlite volcanism, phreatomagmatic and phreatic activity, produce volcanic vents exhibiting a wide variety of morphologies, including vertical pipes and V-shaped vents. In this study we report on experimental and numerical models designed to capture a range of vent morphologies in an eruptive system (Galland et al., 2014). Using dimensional analysis, we identified key governing dimensionless parameters, in particular the gravitational stress-to-fluid pressure ratio (Π2=P/rho.g.h), and the fluid pressure-to-host rock strength ratio (Π3=P/C). We used combined experimental and numerical models to test the effects of these parameters. The experiments were used to test the effect of Π2 on vent morphology and dynamics. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high values of Π2, and diagonal ones at low values of Π2. The numerical simulations were used to test the effect of Π3 on vent morphology and dynamics. In the numerical models we see three distinct morphologies: vertical pipes are produced at high values of Π3, diagonal pipes at low values of Π3, while horizontal sills are produced for intermediate values of Π3. Our results show that vertical pipes form by plasticity-dominated yielding for high-energy systems (high Π2 and Π3), whereas diagonal and horizontal vents dominantly form by fracturing for lower-energy systems (low Π2 and Π3). Although our models are 2-dimensionnal, they suggest that circular pipes result from plastic yielding of the host rock in a high-energy regime, whereas V-shaped volcanic vents result from fracturing of the host rock in lower-energy systems. Galland, O., Gisler, G.R., Haug, Ø.T., 2014. Morphology and dynamics of explosive vents through cohesive rock formations. J. Geophys. Res. 119, 10.1002/2014JB011050.

  19. Waterfall erosion, rock toppling, and the formation of amphitheater-headed canyons in fractured rock

    NASA Astrophysics Data System (ADS)

    Lamb, M. P.; Dietrich, W. E.

    2008-12-01

    Networks of valleys with amphitheater-shaped headwalls are prominent features on the surface of Mars. These landforms are commonly used as diagnostic indicators of undermining and headwall retreat by groundwater-seepage erosion. Of perhaps any canyon ever studied, Box Canyon, Idaho, most strongly meets the proposed morphologic criteria for groundwater sapping because it is incised into a basaltic plain with no drainage network development upstream, and approximately 10 m3/s of seepage emanates from its vertical headwall. However, we have found strong evidence that this canyon was carved during large-scale flooding about 45,000 years ago. Such evidence includes 4He and 14C dates, plunge pools, large boulders, and scoured rock along the rim of the canyon headwall. To explain the formation of the amphitheater headwall of Box Canyon, we propose that near vertical knickpoints can persist during retreat due to waterfall- induced toppling in fractured rock (e.g., columnar basalt). At a waterfall, rock columns are affected by shear and drag from the overflowing water, buoyancy from the plunge pool at the foot of the waterfall, and gravity. A torque balance is used to determine the stability of a rock column and any individual blocks that compose the column. Model results and flume experiments indicate that rotational toppling failure should occur about the base of a headwall (and therefore preserve its form during upstream propagation) where columns are tilted in the downstream direction, or slightly tilted in the upstream direction depending on the plunge pool height. We propose that such conditions are probably common in columnar-basalt bedrock. Thus, our toppling model might explain the origin of steep amphitheater headwalls in volcanic terrains on Earth and Mars by overflowing water and in the absence of seepage.

  20. Clay mineral formation and transformation in rocks and soils

    USGS Publications Warehouse

    Eberl, D.D.

    1983-01-01

    Three mechanisms for clay mineral formation (inheritance, neoformation, and transformation) operating in three geological environments (weathering, sedimentary, and diagenetic-hydrothermal) yield nine possibilities for the origin of clay minerals in nature. Several of these possibilities are discussed in terms of the rock cycle. The mineralogy of clays neoformed in the weathering environment is a function of solution chemistry, with the most dilute solutions favoring formation of the least soluble clays. After erosion and transportation, these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size. Clays undergo little reaction in the ocean, except for ion exchange and the neoformation of smectite; therefore, most clays found on the ocean floor are inherited from adjacent continents. Upon burial and heating, however, dioctahedral smectite reacts in the diagenetic environment to yield mixed-layer illite-smectite, and finally illite. With uplift and weathering, the cycle begins again. Refs.

  1. Growing Pebbles and Conceptual Prisms - Understanding the Source of Student Misconceptions about Rock Formation.

    ERIC Educational Resources Information Center

    Kusnick, Judi

    2002-01-01

    Analyzes narrative essays--stories of rock formation--written by pre-service elementary school teachers. Reports startling misconceptions among preservice teachers on pebbles that grow, human involvement in rock formation, and sedimentary rocks forming as puddles as dry up, even though these students had completed a college level course on Earth…

  2. Simulation of production and injection performance of gas storage caverns in salt formations

    SciTech Connect

    Hagoort, J. )

    1994-11-01

    This paper presents a simple yet comprehensive mathematical model for simulation of injection and production performance of gas storage caverns in salt formations. The model predicts the pressure and temperature of the gas in the cavern and at the wellhead for an arbitrary sequence of production and injection cycles. The model incorporates nonideal gas properties, thermodynamic heat effects associated with gas expansion and compression in the cavern and tubing, heat exchange with the surrounding salt formation, and non-uniform initial temperatures but does not include rock-mechanical effects. The model is based on a mass and energy balance for the gas-filled cavern and on the Bernoulli equation and energy balance for flow in the wellbore. Cavern equations are solved iteratively at successive timesteps, and wellbore equations are solved within an iteration cycle of the cavern equations. Gas properties are calculated internally with generally accepted correlations and basic thermodynamic relations. Example calculations show that the initial temperature distribution has a strong effect on production performance of a typical gas storage cavern. The primary application of the model is in the design, planning, and operation of gas storage projects.

  3. Preliminary Rock Physics Analysis on Lodgepole Formation in Manitoba, Canada

    NASA Astrophysics Data System (ADS)

    Kim, N.; Keehm, Y.

    2012-12-01

    We present rock physics analysis results of Lodgepole Formation, a carbonate reservoir in Daly Field, Manitoba, Canada. We confirmed that the Lodgepole Formation can be divided into six units in the study area: Basal Limestone, Cromer Shale, Cruickshank Crinoidal, Cruickshank Shale, Daly member and Flossie Lake member from the bottom, using eight well log data and previous works. We then performed rock physics analyses on four carbonate units (Basal Limestone, Cruickshank Crinoidal, Daly and Flossie Lake), such as Vp-porosity, AI-porosity, DEM (differential effective medium) modeling, and fluid substitution analysis. In Vp-porosity domain, the top unit, Flossie Lake member has lower porosity and higher velocity, while the other units show similar porosity and velocity. We think that this results from the diagenesis of Flossie Lake member since it bounds with unconformity. However, the four units show very similar trend in Vp-porosity domain, and we can report one Vp-porosity relation for all carbonate units of the Lodgepole formation. We also found that the acoustic impedance varies more than 10% from low porosity zone (3-6%) to high porosity zone (9-12%) from AI-porosity analysis. Thus one can delineate high porosity zone from seismic impedance data. DEM modeling showed that Flossie Lake would have relatively low aspect ratio of pores than the others, which implies that the top unit has been influenced by diagenesis. To determine fluid sensitivity of carbonate units, we conducted fluid substitution on four units from 100% water to 100% oil. The top unit, Flossie Lake, showed slight increase of Vp, which seems to be density effect. The others showed small decrease of Vp, but not significant. If we observe Vp/Vs rather than Vp, the sensitivity increases. However, fluid discrimination would be difficult because of high stiffness of rock frame. In summary, three lower carbonate units of Lodgepole Formation would be prospective and high porosity zone can be delineated

  4. Origin of Dolostone reservoir rocks, smackover formation (Oxfordian), northeastern Gulf Coast, U. S. A

    SciTech Connect

    Prather, B.E. )

    1993-09-01

    Geochemical and petrographic data suggest that, despite the effects of recrystallization, formation of regionally extensive dolostone reservoir rocks in the Smackover Formation can be deciphered. These data indicate that dolomitization took place in (1) seawater seepage, (2) reflux, (3) near-surface mixed-water, (4) shallow-burial mixed-water, and (5) deeper burial environments, which overlapped in time and space to form a platform-scale dolostone body composed of a complex mixture of dolomites. Seawater-seepage and reflux dolomitization occurred in near-surface environments penecontemporaneous with deposition of the Smackover and overlying Haynesville formations. Dolomitization by seawater seepage occurred within an oolite grainstone sill that separated an intraplatform salt basin from the open Late Jurassic sea. Seawater flowed landward through the sill in the response to evaporitic drawdown of brines in the isolated intraplatform basin during a lowstand of Late Jurassic sea level. Dolomite enriched in [sup 18]O located at the top of the Smackover suggests additional dolomitization by reflux of hypersaline brines. Reflux occurred as Buckner coastal sabkhas prograded over Smackover oolite grainstone shoreface deposits. Vugs lined with shallow-burial calcite and dolomite cements indicate flushing of the Smackover grainstone aquifer with fresh water. Freshwater intrusion probably occurred along the Smackover's updip limit and subcrop following sea level lowstands during the Late Jurassic and Early Cretaceous. Leaching in the proximal part of the freshwater aquifer produced excellent-quality limestone reservoir rocks in the updip Smackover. Dolomitization in the contemporaneous downdip mixed connate/freshwater zone formed dolostone reservoir rocks with depleted isotopic compositions consistent with a shallow-burial mixed-water origin.

  5. Aspects of the thermal and transport properties of crystalline salt in designing radioactive waste storages in halogen formations

    SciTech Connect

    Nikitin, A. N. Pocheptsova, O. A.; Matthies, S.

    2010-05-15

    Some of the properties of natural rock salt are described. This rock is of great practical interest, because, along with its conventional applications in the chemical and food industries, it is promising for use in engineering underground radioactive waste storages and natural gas reservoirs. The results of structural and texture studies of rock salt by neutron diffraction are discussed. The nature of the salt permeability under temperature and stress gradients is theoretically estimated.

  6. Uniaxial creep as a control on mercury intrusion capillary pressure in consolidating rock salt

    SciTech Connect

    Dewers, Thomas; Heath, Jason E.; Leigh, Christi D.

    2015-09-01

    The nature of geologic disposal of nuclear waste in salt formations requires validated and verified two - phase flow models of transport of brine and gas through intact, damaged, and consolidating crushed salt. Such models exist in oth er realms of subsurface engineering for other lithologic classes (oil and gas, carbon sequestration etc. for clastics and carbonates) but have never been experimentally validated and parameterized for salt repository scenarios or performance assessment. Mo dels for waste release scenarios in salt back - fill require phenomenological expressions for capillary pressure and relative permeability that are expected to change with degree of consolidation, and require experimental measurement to parameterize and vali date. This report describes a preliminary assessment of the influence of consolidation (i.e. volume strain or porosity) on capillary entry pressure in two phase systems using mercury injection capillary pressure (MICP). This is to both determine the potent ial usefulness of the mercury intrusion porosimetry method, but also to enable a better experimental design for these tests. Salt consolidation experiments are performed using novel titanium oedometers, or uniaxial compression cells often used in soil mech anics, using sieved run - of - mine salt from the Waste Isolation Pilot Plant (WIPP) as starting material. Twelve tests are performed with various starting amounts of brine pore saturation, with axial stresses up to 6.2 MPa (%7E900 psi) and temperatures to 90 o C. This corresponds to UFD Work Package 15SN08180211 milestone "FY:15 Transport Properties of Run - of - Mine Salt Backfill - Unconsolidated to Consolidated". Samples exposed to uniaxial compression undergo time - dependent consolidation, or creep, to various deg rees. Creep volume strain - time relations obey simple log - time behavior through the range of porosities (%7E50 to 2% as measured); creep strain rate increases with temperature and applied stress as

  7. Rupture dimensions and rupture processes of fluid-induced microcracks in salt rock

    NASA Astrophysics Data System (ADS)

    Dahm, T.

    2001-08-01

    We developed and applied a simple empirical Green function method to study induced microcracks observed during hydraulic fracturing experiments in salt rock. Either unidirectional ruptures on rectangular faults or allround ruptures on elliptical faults are tested to explain the observed directivity effects in body-wave amplitude spectra. Mostly, the rectangular rupture model and horizontal fault planes are favored. The average rupture lengths are between 15 and 27 mm, the average rupture durations between 14 and 26 μs. Small average rupture velocities of 30% of the S-wave velocity of the rock are indicated. The dispersive low-frequency coda-waves present in the data look similar to coda-waves observed during other hydraulic fracturing experiments and to long-period events from some volcanoes, which have been explained by the resonance of a fluid-filled crack. The radiation pattern of first motion amplitudes of most events is dominated by a dip-slip double-couple indicating slip on horizontal or vertical planes. We cannot distinguish whether the observed low-frequency coda-waves are influenced by a source effect or by a possible sensor-borehole coupling. However, a simple method using Gauss filter at different center frequencies and relocation is tested to analyze the low-frequency coda-waves in terms of source models.

  8. Stress corrosion of ASTM Grade-2 and Grade-12 titanium in simulated rock salt brines at 83/sup 0/C

    SciTech Connect

    Jain, H.; Ahn, T.M.; Soo, P.

    1983-01-01

    Slow-strain-rate tests have been conducted on Grade-2 and Grade-12 titanium in simulated rock salt brines at 83/sup 0/C. Although neither metal shows stress corrosion cracking, total elongation and reduction in area show some decrease. Optical and SEM results are discussed to elucidate the fracture mechanism.

  9. A1 and A2, two novel haloarchaeal isolates from bore cores of ancient Alpine rock salt deposits

    NASA Astrophysics Data System (ADS)

    Gruber, C.; Pfaffenhuemer, M.; Weidler, G.; Radax, C.; Stan-Lotter, H.

    2003-04-01

    Previously several novel halophilic archaea, for instance Haloccocus salifodinae BIp and Halococcus dombrowskii, were isolated from Permo-Triassic rock salt (age 200 - 250 million years) in our laboratory. By using molecular methods we found evidence for the presence of numerous additional haloarchaeal taxa. We investigated freshly drilled salt cores from a depth of about 600 m below surface in the salt mine of Altaussee, Austria, which were dissolved immediately in sterile water. After plating the dissolved salts on high salt nutrient agar, we were able to isolate, following incubation for 3 months, two red pigmented colonies, which were designated A1 and A2 and cultivated for further investigation. A1 and A2 showed the same antibiotic susceptibility as Halobacterium salinarum DSM 3754 and Halobacterium sp. NRC-1, which were cultivated from surface waters. Additionally, the cell morphology of the new isolates was highly similar to both reference strains. According to 16S rRNA gene sequences, whole cell protein patterns following SDS polyacrylamide gel electrophoresis, and restriction digestion patterns of their DNA following pulsed field gel electrophoresis, the isolates A1 and A2 could not be distinguished. 16S rRNA gene sequences indicated that the closest relative of strains A1 and A2 was Halobacterium salinarum DSM 3754 (sequence similarity 97,1%). Our results suggest that the isolates A1 and A2 might constitute a new haloarchaeal species, entrapped in ancient rock salt.

  10. Sulfate-dependent Anaerobic Oxidation of Methane as a Generation Mechanism for Calcite Cap Rock in Gulf Coast Salt Domes

    NASA Astrophysics Data System (ADS)

    Caesar, K. H.; Kyle, R.; Lyons, T. W.; Loyd, S. J.

    2015-12-01

    Gulf Coast salt domes, specifically their calcite cap rocks, have been widely recognized for their association with significant reserves of crude oil and natural gas. However, the specific microbial reactions that facilitate the precipitation of these cap rocks are still largely unknown. Insight into the mineralization mechanism(s) can be obtained from the specific geochemical signatures recorded in these structures. Gulf Coast cap rocks contain carbonate and sulfur minerals that exhibit variable carbon (d13C) and sulfur isotope (δ34S) signatures. Calcite d13C values are isotopically depleted and show a large range of values from -1 to -52‰, reflecting a mixture of various carbon sources including a substantial methane component. These depleted carbon isotope compositions combined with the presence of abundant sulfide minerals in cap rocks have led to interpretations that invoke microbial sulfate reduction as an important carbonate mineral-yielding process in salt dome environments. Sulfur isotope data from carbonate-associated sulfate (CAS: trace sulfate incorporated within the carbonate mineral crystal lattice) provide a more direct proxy for aqueous sulfate in salt dome systems and may provide a means to directly fingerprint ancient sulfate reduction. We find CAS sulfur isotope compositions (δ34SCAS) significantly greater than those of the precursor Jurassic sulfate-salt deposits (which exhibit δ34S values of ~ +15‰). This implies that cap rock carbonate generation occurred via microbial sulfate reduction under closed-system conditions. The co-occurrence of depleted carbonate d13C values (< ~30‰) and the enriched δ34SCAS values are evidence for sulfate-dependent anaerobic oxidation of methane (AOM). AOM, which has been shown to yield extensive seafloor carbonate authigenesis, is also potentially partly responsible for the carbonate minerals of the Gulf Coast calcite cap rocks through concomitant production of alkalinity. Collectively, these data shed

  11. Laboratory Evaluation of Damage Criteria and Creep Parameters of Tioga Dolomite and Rock Salt from Cavern Well No. 1

    SciTech Connect

    LEE, MOO Y.; EHGARTNER, BRIAN L.

    2002-04-01

    A suite of laboratory triaxial compression and triaxial steady-state creep tests provide quasi-static elastic constants and damage criteria for bedded rock salt and dolomite extracted from Cavern Well No.1 of the Tioga field in northern Pennsylvania. The elastic constants, quasi-static damage criteria, and creep parameters of host rocks provides information for evaluating a proposed cavern field for gas storage near Tioga, Pennsylvania. The Young's modulus of the dolomite was determined to be 6.4 ({+-}1.0) x 10{sup 6} psi, with a Poisson's ratio of 0.26 ({+-}0.04). The elastic Young's modulus was obtained from the slope of the unloading-reloading portion of the stress-strain plots as 7.8 ({+-}0.9) x 10{sup 6} psi. The damage criterion of the dolomite based on the peak load was determined to be J{sub 2}{sup 0.5} (psi) = 3113 + 0.34 I{sub 1} (psi) where I{sub 1} and J{sub 2} are first and second invariants respectively. Using the dilation limit as a threshold level for damage, the damage criterion was conservatively estimated as J{sub 2}{sup 0.5} (psi) = 2614 + 0.30 I{sub 1} (psi). The Young's modulus of the rock salt, which will host the storage cavern, was determined to be 2.4 ({+-}0.65) x 10{sup 6} psi, with a Poisson's ratio of 0.24 ({+-}0.07). The elastic Young's modulus was determined to be 5.0 ({+-}0.46) x 10{sup 6} psi. Unlike the dolomite specimens under triaxial compression, rock salt specimens did not show shear failure with peak axial load. Instead, most specimens showed distinct dilatancy as an indication of internal damage. Based on dilation limit, the damage criterion for the rock salt was estimated as J{sub 2}{sup 0.5} (psi) = 704 + 0.17 I{sub 1} (psi). In order to determine the time dependent deformation of the rock salt, we conducted five triaxial creep tests. The creep deformation of the Tioga rock salt was modeled based on the following three-parameter power law as {var_epsilon}{sub s} = 1.2 x 10{sup -17} {sigma}{sup 4.75} exp(-6161/T), where {var

  12. Preliminary rock physics analysis on Grosmont carbonate formation, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Hu, D.; Keehm, Y.

    2009-12-01

    Grosmont formation in Canada is a bitumen-saturated carbonate reservoir and draw increasing attention as a possible future unconventional oil field. However, the characterization of the formation is not easy due to high geological complexity. In this paper, we report our preliminary results of rock physics modeling effort using log data from seven wells in the T85R19W4 township, Alberta, Canada. Since the acoustic and shear velocity data are not very common, we use three logging properties: gamma ray; neutron-density porosity; and resistivity. The bitumen saturation is obtained from core measurement data. From the preliminary analysis, Grosmont formation can be divided into two groups by resistivity and porosity. The lower group matches with Grosmont A and B from previous studies and upper group with Grosmont C and D. The lower group mainly consists of limestone with different clay contents. The upper group was under dolomitization and karstification during Mesozoic, and is composed of fractured dolomite and karst breccia. The two groups can be divided by 15% porosity and 100 ohm-m resistivity values. The upper group has higher porosity and higher resistivity, which indicates high bitumen saturation and better reservoir quality. In porosity-resistivity domain, some wells shows typical trend; resistivity increases as porosity decrease; however, wells from the north-eastern part does not show any consistent trends. We believe that north-eastern part of our study area has more dolomitization and karstification, thus higher heterogeneity. We report basic trends for porosity vs. resistivity using Hashin-Shtrikman bounds for upper and lower group at each well. We also plan to obtain velocity data and perform quantitative analysis on porosity-velocity relations and velocity sensitivity to bitumen saturation. Acknowledgement: This research was funded by Energy Efficiency and Resources Program of KETEP (Korea Institute of Energy Technology Evaluation and Planning), Grant No

  13. The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona

    USGS Publications Warehouse

    Fuis, Gary S.

    1996-01-01

    The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

  14. The Influence of the De-Icing Salt on the Deterioration of Rock Materials Used in Monumental Buildings

    NASA Astrophysics Data System (ADS)

    Kłopotowska, Agnieszka Katarzyna; Łukaszewski, Paweł

    2013-09-01

    The de-icing salt has been used for decades to increase safety on the roads and sidewalks. In Poland, mainly the sodium chloride is used in order to maintain the roads in good condition during winter. Like other salts used for surface de-icing, it depresses the freezing point to lower temperatures and has an additional thermal effect by an exothermic reaction. However, this salt causes the accumulation of chlorides in the walls and stone buildings contributing to the deterioration of these facilities. The paper addresses the issue of the influence of salt solutions on the structure and geomechanical properties of rocks at negative temperatures. The study was conducted on the basis of cyclic tests which simulate complex action of both the negative temperature and the salty environment. The conditions for the tests were chosen so as to reflect the actual conditions of the winter in Poland. During the tests, the longitudinal wave propagation velocity, changes in weights of the samples as well as visual changes were recorded which allowed continuous tracking of occurring changes. At the end of the tests, the rock samples were subjected to uniaxial compressive tests. For this purpose, four lithological types were chosen, representing the sedimentary rocks: clastic and carbonate, widely used in stone constructions.

  15. Proceedings of the international symposium on engineering in complex rock formations

    SciTech Connect

    Not Available

    1988-01-01

    This book contains over 100 papers. Some of the titles are: Rheology of rock-salt and its application for radioactive waste disposal purposes; A scale model study on the deformation around the drift in Korean inclined coal seam; Stabilization of a landslide in fractured marls and limestone; Dead Sea underground hydroelectric power station; and Rock mechanics in design of underground power house of lubuge hydropower project.

  16. Pre-existing caverns in salt formations could be the major cause of sinkhole hazards along the coast of the Dead Sea

    NASA Astrophysics Data System (ADS)

    Legchenko, A.; Ezersky, M.; Boucher, M.; Camerlynck, C.; Al-Zoubi, A.; Chalikakis, K.

    2008-10-01

    Since 1990 hundreds of sinkholes have appeared along the coast of the Dead Sea. In the literature the rapid development of sinkholes is explained as a result of a drop in the level of the Dead Sea. This model assumes very fast dissolution of large volumes of salt and the creation of new caverns that cause sinkholes in 10 to 20 years. However, the results of our geophysical study do not confirm the fast dissolution assumption. To explain the available field observations, we propose the following model: (1) slow dissolution of salt (much longer than 20 years) with the creation of caverns without development of sinkholes; (2) sinkhole development is triggered by the lowering of the groundwater level because the rocks overlying the salt formation become unsaturated; (3) the time of sinkhole appearance is controlled by the mechanical properties of the rocks that overlie pre-existing caverns.

  17. Simulation of Cavern Formation and Karst Development Using Salt

    ERIC Educational Resources Information Center

    Kent, Douglas C.; Ross, Alex R.

    1975-01-01

    A salt model was developed as a teaching tool to demonstrate the development of caverns and karst topography. Salt slabs are placed in a watertight box to represent fractured limestone. Erosion resulting from water flow can be photographed in time-lapse sequence or demonstrated in the laboratory. (Author/CP)

  18. Formation of ordered metal nanowire-inorganic salt composites

    NASA Astrophysics Data System (ADS)

    Novikov, V. P.; Stetsik, A. N.; Neden', S. R.

    2007-05-01

    A new phenomenon accompanying the electrolysis of salts has been observed, whereby an ordered composite is formed under certain conditions (electrolyte composition, current density). The composite comprises an inorganic salt crystal penetrated by metal nano- and microwires. This phenomenon can serve as a basis for the technology of oriented and ordered nanowire array synthesis.

  19. Role of halite in the evolution of sandstone porosity, upper Jurassic Norphlet Formation, Mississippi salt basin

    SciTech Connect

    Schenk, C.J.; Schmoker, J.W. )

    1993-09-01

    Analysis of petrographic point-count data, cement paragenesis, and scanning electron microscopy examination of pores has shown that poikilitic halite cement in sandstones of the Norphlet Formation in a core from Wayne County, Mississippi, formed following cementation by quartz, feldspar, dolomite, and anhydrite. Intergranular volume ranges from 26 to 42%, averaging 35%, indicating that an average of 10% of the rock volume was lost to compaction, and a further 10-15%, was lost to cementation prior to halite cementation, assuming a depositional porosity of about 45%. Most halite occurs as intergranular cement, but some halite is present as intragranular cement within framework feldspars and lithic fragments. Halite is easily removed from a sandstone during coring, slabbing, and thin-section preparation techniques that do not use oil-based fluids and muds, so the amount of porosity in these samples that is a product of artificial removal of halite is unknown. Although the present and former distribution of halite is poorly known, natural halite dissolution could have produced about 20% secondary porosity in the Norphlet Formation at depth in this part of the Mississippi Salt basin.

  20. Geodynamically unusual settings of sedimentary rock and ore formation due to tectonic-decompression effects

    SciTech Connect

    Goryainov, P.M.

    1984-05-01

    The traditional views of terrigenous rocks as products of classical sedimentary cycle, ''mobilization-transport-deposition,'' are not universal. Detrital rocks are sometimes formed due to flaking and fracturation of rocks of rising blocks. The process is produced by tectonic-decompression mechanisms - the origination of a gradient of excessive stress and its discharge. It is incorrect to classify rocks created by this phenomenon with weathering crusts. The origins of certain terrigenous rocks, as well as products of low-temperature chemical processing, are connected with deep-volume decompression (brecciation, stockwork formation, formation of pipes and columns of igneous rocks, and chamber pegmatite and karst formation). The ore concentrations associated with such entities and appearing as stratiform deposits are most likely not exogenous, but they complete the endogenous history of the block concerned. The means and methods tested on typical endogenous deposits may therefore prove valuable in predicting certain varieties of stratiform deposits.

  1. Effects of Hofmeister salt series on gluten network formation: Part I. Cation series.

    PubMed

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different cationic salts were used to investigate the effects of the Hofmeister salt series on gluten network formation. The effects of cationic salts on wheat flour dough mixing properties, the rheological and the chemical properties of the gluten extracted from the dough with different respective salts, were investigated. The specific influence of different cationic salts on the gluten structure formation during dough mixing, compared to the sodium ion, were determined. The effects of different cations on dough and gluten of different flours mostly followed the Hofmeister series (NH4(+), K(+), Na(+), Mg(2+) and Ca(2+)). The impacts of cations on gluten structure and dough rheology at levels tested were relatively small. Therefore, the replacement of sodium from a technological standpoint is possible, particularly by monovalent cations such as NH4(+), or K(+). However the levels of replacement need to take into account sensory attributes of the cationic salts. PMID:27374596

  2. The use of thick-walled hollow cylinder creep tests for evaluating flow criteria for rock salt

    SciTech Connect

    Morgan, H.S.; Wawersik, W.R.

    1990-01-01

    Finite element simulations of two laboratory creep tests on thick-walled hollow cylinders of rock salt are evaluated to determine if such bench-scale experiments can be used to establish applicability of either von Mises or Tresca stress measures and associated flow conditions. In the tests, the cylinders were loaded axially and pressurized both internally and externally to produce stress fields similar to those found around underground excavations in rock salt. Several different loading stages were used in each test. The simulations show that for each of two creep models studied, quite different deformations of the cylinders are predicted with the Mises and Tresca flow criteria, especially if friction between the cylinders and axial loading platens is ignored. When friction is included in the simulations, the differences in deformation are changed but are sill clearly distinguishable. 10 refs., 10 figs.

  3. Salt Marsh Formation in the Lower Hudson River Estuary

    NASA Technical Reports Server (NTRS)

    Merley, Michael; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

    2001-01-01

    Salt marshes are constant depositional environments and as a result contain accurate indicators of past relative sea level rise and salinity. The Hudson River marshes are at least twice as deep when compared to coastal marshes on either side of the mouth of the Hudson. The reason for this difference in sedimentation is unclear. This study uses macrofossil data as well as sediment stratigraphy in order to understand the formation and evolution of these marshes. The composition of seeds, roots, shoots and foraminifera, are used to indicate past sea levels. The four sites involved in this study are, from south to north, the Arthur Kill Marsh in Staten Island (40 36 N, 74 77W), Piermont marsh (N 4100; 73 55W) Croton Point (41 14 N; 73 50W) and Iona Island (41 18N, 73 58W). These are all tidally influenced but with increasing distances from the New York Bight, which gives a good spectrum of tidal influence. AMS-C14 dates on basal macrofossils will document the time of each marsh formation. Basal material from Arthur Kill (8 m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10 m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77 m) is lacking any identifiable macrofossils between 150 and 500 microns. The basal material from Iona Island (10 m) has vegetation such as Scirpus and Cyperus seeds, probably implying a brackish environment. The freshwater origin of the Arthur Kill marsh in Staten Island is significant because it predates either sea level rise or the western channel incision. Additional implications for this study include evidence for changes in river channel geomorphology. Reasons for the relatively deeper river marshes include possible basal clay compaction, high production due to river and marine nutrients as well as tectonic activity. This study provides the groundwork for more high

  4. The application of high resolution X-ray computed tomography on naturally deformed rock salt: Multi-scale investigations of the structural inventory

    NASA Astrophysics Data System (ADS)

    Thiemeyer, Nicolas; Habersetzer, Jörg; Peinl, Mark; Zulauf, Gernold; Hammer, Jörg

    2015-08-01

    X-ray computed tomography (CT) represents a useful technique providing new perspectives and insights for the structural investigation of naturally-deformed rock salt. Several samples of Permian rock salt from Gorleben, Asse and Teutschenthal (Germany) were investigated by exploiting the non-destructive nature of μCT and nCT techniques particularly for salt rocks. CT imaging enabled the visualization and quantification of anhydrite impurities, pore space and fluid phases located along grain-boundaries or trapped as intracrystalline inclusions. Disseminated grains and aggregates of anhydrite in rock salt of the Gorleben salt dome have been visualized and quantified by μCT for the first time in order to portray their spatial occurrence. The visualization of anhydrite aggregates and pore space shows no correlation between their spatial distributions. This independence excludes the anhydrite to be responsible for elevated porosity (0.87 ± 0.07 vol.-%). High-resolution nCT scans (≤1 μm voxel size) of single intracrystalline and grain-boundary fluid inclusions from Gorleben and Asse rock salt allowed the visualization and quantification of their various phase components. A major achievement is the detailed description of the morphology and shape of the fluid inclusions and of their phase components, which has not been conducted in rock salt research by high-resolution X-ray CT imaging before.

  5. Effects of Hofmeister salt series on gluten network formation: Part II. Anion series.

    PubMed

    Tuhumury, H C D; Small, D M; Day, L

    2016-12-01

    Different anion salts from the Hofmeister series were used to investigate their effects on gluten network formation. The effects of these anion salts on the mixing properties of the dough and the rheological and chemical properties of gluten samples extracted from the dough with these respective salts were compared. The aim of this work was to determine how different anion salts influence the formation of the gluten structure during dough mixing. It was found that the Hofmeister anion salts affected the gluten network formation by interacting directly with specific amino acid residues that resulted in changes in gluten protein composition, specifically the percentage of the unextractable polymeric protein fractions (%UPP). These changes consequently led to remarkable differences in the mixing profiles and microstructural features of the dough, small deformation rheological properties of the gluten and a strain hardening behaviour of both dough and gluten samples. PMID:27374597

  6. Water-rock interactions in warm Enceladus inferred from silica formation and hydrothermal experiments

    NASA Astrophysics Data System (ADS)

    Sekine, Yasuhito; Shibuya, T.; Postberg, F.; Hsu, H.; Suzuki, K.; Masaki, Y.; Kuwatani, T.; Tachibana, S.

    2013-10-01

    A plume of vapour and water ice particles rich in sodium salts erupting from warm fractures near the south pole of Saturn’s icy moon Enceladus suggest the presence of a liquid-water reservoir in the interior, which is or has been in contact with the moon’s rocky core. Cassini’s findings of silica nanoparticles in the E-ring originating from the plumes imply active geochemistry involving hydrothermal water-rock interactions. However, the particular conditions of temperature and mineral compositions that can sustain the formation of silica inside Enceladus are yet unconstrained. Here we report laboratory experiments and numerical calculations of hydrothermal reactions simulating Enceladus’ interior. To achieve silica concentrations in the fluids, which are sufficient for the formation of colloidal silica nanoparticles, hydrous silicates of Enceladus’ core would be composed mainly of serpentine and saponite/talc, consistent with a chondritic composition of its rocky core. Fluid temperature needs to reach ≥ ~100°C, suggesting extensive hydrothermal activity. Our experimental results suggest that, in contrast to previous reports, a lack of N2 in the plumes is in good agreement with a hot interior because decomposition of primordial NH3 to N2 would have been kinetically inhibited even at high temperatures (i.e., ~400°C). These results support the idea that deep hydrothermal circulation in a warm core drives hotspots in the ice mantle, possibly causing large tidal dissipation and anomalous heat flux from the south-pole region. Furthermore, to achieve such high temperatures in Enceladus, the Saturnian system might have formed in ~3-5 Myrs after the CAIs formation in the protoplanetary disk, consistent with the proposed formation age for another moon of Saturn, Iapetus.

  7. Groundwater compatibility with formation water and pay zone rocks in Pervomaysk oil-gas-condensate field to maintain formation pressure

    NASA Astrophysics Data System (ADS)

    Trifonov, N.; Nazarov, A.; Alekseev, S.

    2016-03-01

    The paper describes the research results in determining the compatibility of groundwater from Aptain-Albian-Cenomanian aquifer with formation water and pay zone rocks in U1 layer sediments, Pervomaysk oil field.

  8. Emergent nanoscale fluctuations in high rock-salt PbTe

    NASA Astrophysics Data System (ADS)

    Billinge, Simon

    2013-03-01

    Lead Telluride is one of the most promising thermoelectric materials in the temperature range just above room temperature. It is a narrow band gap semiconductor with a high Seebeck coefficient and a low thermal conductivity. It is structurally much simpler than many other leading candidates for high performance thermoelectrics being a binary rock-salt, isostructural to NaCl. The thermoelectric figure of merit, ZT, can be markedly improved by alloying with various other elements by forming quenched nanostructures. The undoped endmember, PbTe, does not have any such quenched nanostructure, yet has a rather low intrinsic thermal conductivity. There are also a number of interesting and non-canonical behaviors that it exhibits, such as an increasing measured band-gap with increasing temperature, exactly opposite to what is normally seen due to Fermi smearing of the band edge, and an unexpected non-monotonicity of the band gap in the series PbTe - PbSe - PbS. The material is on the surface simple, but hides some interesting complexity. We have investigated in detail the PbTe endmember using x-ray and neutron diffraction and neutron inelastic scattering. To our surprise, using the atomic pair distribution function (PDF) analysis of neutron powder diffraction data we found that an interesting and non-trivial local structure that appears on warming. with the Pb atoms moving off the high-symmetry rock-salt positions towards neighboring Te ions. No evidence for the off-centering of the Pb atoms is seen at low temperature. The crossover from the locally undistorted to the locally distorted state occurs on warming between 100 K and 250 K. This unexpected emergence of local symmetry broken distortions from an undistorted ground-state we have called emphanisis, from the Greek for appearing from nothing. We have also investigated the lattice dynamics of the system to search for a dynamical signature of this behavior and extended the studies to doped systems and I will also

  9. Rocks.

    ERIC Educational Resources Information Center

    Lee, Alice

    This science unit is designed for limited- and non-English speaking students in a Chinese bilingual education program. The unit covers rock material, classification, characteristics of types of rocks, and rock cycles. It is written in Chinese and simple English. At the end of the unit there is a list of main terms in both English and Chinese, and…

  10. Permeability of natural rock salt from the Waste Isolation Pilot Plant (WIPP) during damage evolution and healing

    SciTech Connect

    Pfeifle, T.W.

    1998-06-01

    The US Department of Energy has developed the Waste Isolation Pilot Plant (WIPP) in the bedded salt of southeastern New Mexico to demonstrate the safe disposal of radioactive transuranic wastes. Four vertical shafts provide access to the underground workings located at a depth of about 660 meters. These shafts connect the underground facility to the surface and potentially provide communication between lithologic units, so they will be sealed to limit both the release of hazardous waste from and fluid flow into the repository. The seal design must consider the potential for fluid flow through a disturbed rock zone (DRZ) that develops in the salt near the shafts. The DRZ, which forms initially during excavation and then evolves with time, is expected to have higher permeability than the native salt. The closure of the shaft openings (i.e., through salt creep) will compress the seals, thereby inducing a compressive back-stress on the DRZ. This back-stress is expected to arrest the evolution of the DRZ, and with time will promote healing of damage. This paper presents laboratory data from tertiary creep and hydrostatic compression tests designed to characterize damage evolution and healing in WIPP salt. Healing is quantified in terms of permanent reduction in permeability, and the data are used to estimate healing times based on considerations of first-order kinetics.

  11. Influence of sulphate, chloride, and thiocyanate salts on formation of β-lactoglobulin-pectin microgels.

    PubMed

    Hirt, Stacey; Jones, Owen G; Adijanto, Marilyn; Gilbert, Jay

    2014-12-01

    Effects of sulphate, chloride, and thiocyanate salts on the heat-induced formation of protein-based microgels from β-lactoglobulin-pectin complexes were determined as a function of pH and protein-to-polysaccharide ratio. Aggregation temperatures were initially decreased at low ionic strength due to shielding of electrostatic interactions between β-lactoglobulin and pectin but increased with further increases in ionic strength. Turbidity of heated mixtures and associated sizes of formed microgels were increased with up to 75 mmol kg(-1) ionic strength. Aggregation and microgel formation were relatively increased in the presence of thiocyanate salts compared to chloride salts and relatively decreased in the presence of sulphate salts, indicating that the inverse Hofmeister series was relevant in this system. Topographical analysis of dried microgels by atomic force microscopy verified that microgels were smallest in the presence of sulphate salts and showed that added ions, particularly thiocyanate, increased the deformability of microgels during drying. PMID:24996306

  12. Preliminary analyses of scenarios for potential human interference for repositories in three salt formations

    SciTech Connect

    Not Available

    1985-10-01

    Preliminary analyses of scenarios for human interference with the performance of a radioactive waste repository in a deep salt formation are presented. The following scenarios are analyzed: (1) the U-Tube Connection Scenario involving multiple connections between the repository and the overlying aquifer system; (2) the Single Borehole Intrusion Scenario involving penetration of the repository by an exploratory borehole that simultaneously connects the repository with overlying and underlying aquifers; and (3) the Pressure Release Scenario involving inflow of water to saturate any void space in the repository prior to creep closure with subsequent release under near lithostatic pressures following creep closure. The methodology to evaluate repository performance in these scenarios is described and this methodology is applied to reference systems in three candidate formations: bedded salt in the Palo Duro Basin, Texas; bedded salt in the Paradox Basin, Utah; and the Richton Salt Dome, Mississippi, of the Gulf Coast Salt Dome Basin.

  13. Kinetics of formation of bile salt micelles from coarse-grained Langevin dynamics simulations.

    PubMed

    Vila Verde, Ana; Frenkel, Daan

    2016-06-21

    We examine the mechanism of formation of micelles of dihydroxy bile salts using a coarse-grained, implicit solvent model and Langevin dynamics simulations. We find that bile salt micelles primarily form via addition and removal of monomers, similarly to surfactants with typical head-tail molecular structures, and not via a two-stage mechanism - involving formation of oligomers and their subsequent aggregation to form larger micelles - originally proposed for bile salts. The free energy barrier to removal of single bile monomers from micelles is ≈2kBT, much less than what has been observed for head-tail surfactants. Such a low barrier may be biologically relevant: it allows for rapid release of bile monomers into the intestine, possibly enabling the coverage of fat droplets by bile salt monomers and subsequent release of micelles containing fats and bile salts - a mechanism that is not possible for ionic head-tail surfactants of similar critical micellar concentrations. PMID:27199094

  14. Hydrogeochemical Characterization of Formation Waters in Cretaceous Rocks from Southeast Mexico

    NASA Astrophysics Data System (ADS)

    Mendez-Ortiz, B. A.; Carrillo-Chavez, A.; Tritlla, J.; Levresse, G.; Varela, M.; Clara, L.; Caballero, E.

    2007-05-01

    Formation waters were sampled from ten different producing wells in several Cretaceous oil fields in central and north Tabasco, southeast of Mexico. All of them were analyzed for mayor and trace ions, as well as for 18O and D isotopes. The salinity in the central oil fields (TSD in ppm) ranges from 221,972 ppm to 243,372 ppm. The salinities are very similar in different oil wells. These salinities are 1 to 14 times higher than the salinity found in another fields (15,299 to 16,557 ppm), and 1 to 5 times higher than other field. A northern oil field salinity is characterized also by an important heterogeneity of it salinity due to salt intrusion and interaction with non uniform structures. The major ions analysis (Na+, Ca2+, K+, Mg+, Cl+, SO42-, HCO3-) suggests water-rock interactions in all the oil fields. This is the case, particularly marked in the central fields, where the brines are enriched in Mg in a range from 10 to 274 ppm. This is due to brines/dolomites interaction, while in other oil field, the higher concentration of Mg was only of 1.17 ppm. The central oil fields present depletion on sulfate concentrations (<5.9 ppm). This could be due to precipitation of metal sulfide (thermal reduction) in the form of pyrite and marcasite. Halogens (Br, Cl) concentration indicates three different origins for the formation waters. Water from the central wells is plotted on the evaporated marine water evolution line. Water from the southern wells is located close to marine water in the halite dissolution zone, whereas water form the northern wells is plotted in the diluted waters zone. Cl and Br evolution in the central field samples shows two different groups, and clearly reveal mixing processes between marine water and highly evolved evaporated seawater. Whereas water from the northern wells is plotted in the mixing zone between seawater with low salinity water trapped in Tertiary sediments which can migrate until mixed with older formation waters. The D-O stable

  15. Magnetostratigraphic and radiometric constraints on salt formation in the Qaidam Basin, NE Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Jiuyi; Fang, Xiaomin; Appel, Erwin; Zhang, Weilin

    2013-10-01

    The Qaidam Basin is the largest Cenozoic intermontane basin within the northeast (NE) Tibetan Plateau. It contains large amounts of nonmarine evaporite deposits formed during the Pliocene-Quaternary. Even at present, extensive salt deposits dominated by halite and potash are formed by solar-driven concentration of brine water in the basin interior, making it the most important industrial base for potash exploitation in China. The formation of salt required an arid climatic, appropriate hydrological and tectonic setting through geologic times and will do so in the future. Studying the salt formation in the Qaidam Basin will enhance our understanding of processes driven by saline lake evolution, regional climate change, and tectonic movements, not only for the setting of the Tibetan Plateau. Reliable dating is crucial for assessing the time of salt formation in Qaidam Basin and the accumulation process, yet no comprehensive scientific studies have been reported on this important issue until now. In this paper, we critically review and compile magnetostratigraphic and radiometric studies of the salt-bearing strata within seven depressions of the basin. We find that the ages of salt formation are very different in these depressions: for the Dalangtan, Yiliping, Chahansilatu, and Kunteyi depressions, first salt deposits occurred at >3.90 ± 0.02 Ma, 2.88 ± 0.04 Ma, 2.24 ± 0.01 Ma and 1.18 ± 0.02 Ma, respectively. For the Mahai, Gasikule, and Qarhan, the ages of earliest salt formation are much younger i.e., 302 ± 56 ka, 608 ± 38 ka, and 54-24 ka, respectively. However, the result from Mahai has to be considered with caution. The variability of ages suggests an older salt-forming stage in the center of the western basin and a younger salt accumulation period along the basin margin. In a regional view, previous results from stratigraphy, sedimentology, geomorphology, and tectonic history allow us to conclude that the salt formation in the Qaidam Basin was probably

  16. Winter Ice and Snow as Models of Igneous Rock Formation.

    ERIC Educational Resources Information Center

    Romey, William D.

    1983-01-01

    Examines some features of ice and snow that offer teachers and researchers help in understanding many aspects of igneous processes and configurations. Careful observation of such processes as melting, decay, evolution, and snow accumulation provide important clues to understanding processes by which many kinds of rocks form. (Author/JN)

  17. The influence of mineral detritus on rock varnish formation

    NASA Astrophysics Data System (ADS)

    Dorn, Ronald I.; Krinsley, David H.; Langworthy, Kurt A.; Ditto, Jeffrey; Thompson, Tyler J.

    2013-09-01

    A mix of high resolution electron microscope methods imaged the textures and chemistry of rock varnish samples from 19 field sites on five continents. The vast majority of aeolian mineral is not incorporated into manganiferous rock varnish. Of those dust particles that are enveloped, submicron sized oval-shaped quartz minerals are the most common type of detritus seen, as they rest conformably between laminated layers. The dominance of quartz as the most common detrital mineral, combined with the relative rarity of feldspars - is consistent with the hypothesis that feldspars experience in situ decay into clay minerals. After the detritus is buried in varnish, mineral boundaries often develop enhanced porosity. Some porous zones around dust particles develop submicron skins of redeposited Mn-Fe. In other cases, the porous zones aid in the transport of capillary water that mobilizes and redeposits Mn-Fe as stringers in fissures. Larger dust particles ˜10 μm in diameter are deposited in microtopographic depressions, such as tubes created by acid-producing lithobionts. Varnishes growing in particularly dusty regions form alternating dust-rich and varnish-rich layers that potentially correlate to alternating dusty and less dusty periods. The very foundation of varnish, the underlying rock, is often less stable in the surficial environment than varnish - leading to enhanced porosity and mineral decay in the substrate. Sometimes, physical collapse of varnish into the underlying void space mixes varnish and rock; more commonly, however, remobilization of varnish constituents into these pore spaces creates case hardening of the weathering rind in the underlying rock.

  18. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary.

    PubMed

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-01-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

  19. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

    NASA Astrophysics Data System (ADS)

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-06-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE.

  20. Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

    PubMed Central

    Shaha, Dinesh Chandra; Cho, Yang-Ki

    2016-01-01

    Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

  1. Salting Constants of Small Organic Molecules in Aerosol-Relevant Salts and Application to Aerosol Formation in the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Waxman, E.; Carlton, A. M. G.; Ziemann, P. J.; Volkamer, R. M.

    2014-12-01

    Secondary organic aerosol (SOA) formation from small water-soluble molecules such as glyoxal and methyl glyoxal is a topic of emerging interest. Results from recent field campaigns, e.g. Waxman et al. (2013, GRL) and Knote et al. (2014, ACP), show that these molecules can form significant SOA mass as a result of 'salting-in'. Salting-in happens when a molecule's solubility increases with salt concentration and salting-out is the reverse. Salting effects modify the solubility exponentially with increasing salt concentration, and thus the effective Henry's law constant can strongly modify partitioning, and multiphase chemical reaction rates in aerosol water. Moreover, the solubility in aerosol water cannot easily inferred based on the solubility in cloud water, as the salting effects could change the solubility by a factor of 104 or more. In this work, we have devised and applied a novel experimental setup to measure salting constants using an ion trap mass spectrometer. We focus on small, water soluble molecules like methyl glyoxal and similar compounds and measure salting constants for aerosol-relevant salts including ammonium sulfate, ammonium nitrate, and sodium chloride. The Setschenow salting-constant values are then used to parameterize the effects of salting in CMAQ. We present a series of sensitivity studies of the effects that inorganic aerosols have on the SOA formation from small soluble molecules in the southeastern United States.

  2. Drug salt formation via mechanochemistry: the case study of vincamine.

    PubMed

    Hasa, Dritan; Perissutti, Beatrice; Cepek, Cinzia; Bhardwaj, Sunil; Carlino, Elvio; Grassi, Mario; Invernizzi, Sergio; Voinovich, Dario

    2013-01-01

    In the present research a salt of vincamine, a poorly bioavailable indole alkaloid derived from the leaves of Vinca minor L., was synthesized in the solid state by means of a mechanochemical process employing citric acid as a reagent. The mechanochemical process was adopted as a solvent-free alternative to classical citrate synthetic route that involves the use of solvents. Since the mechanochemical salification is little studied to date and presents the disadvantage of offering a low yield, in this work, the influence of three process and formulation variables on the percentage of vincamine citrate was studied. In particular, the time of mechanical treatment (in planetary mill Fritsch P5) and the amount of citric acid were varied in order to evaluate their effect on the yield of the process, and the introduction of a solid solvent, a common pharmaceutical excipient (sodium carboxymethylcellulose, NaCMC), was considered. Due to the complexity of the resulting samples' matrix, an appropriate experimental design was employed to project the experimental trials and the influence of the three variables on the experimental response was estimated with the help of a statistical analysis. The experimental response, that is, the yield of the process corresponding to the percentage of vincamine in the protonated form, was unconventionally calculated by means of X-ray photoelectron spectroscopy analysis (XPS). Out of 16 samples, the one with the highest yield was the coground sample containing vincamine and citric acid in a 1:2 molar ratio, treated for 60 min in the presence of NaCMC. Under the above conditions the salification reaction was completed highlighting the importance of a proper selection of process and formulation variables of the mechanochemical salification, and emphasizing the crucial role of the solid solvent in facilitating the salification. The second step of the research encompassed the characterization of the citrate salt obtained by solid excipient

  3. Depleted δ13C Values in Salt Dome Cap Rock Organic Matter and Implications for Microbial Metabolism and Fixation

    NASA Astrophysics Data System (ADS)

    Loyd, S. J.; Lu, L.; Caesar, K. H.; Kyle, R.

    2015-12-01

    Salt domes occur throughout the Gulf Coast Region USA and are often associated with trapped hydrocarbons. These salt domes can be capped by sulfate and carbonate minerals that result from complex digenetic interactions in the subsurface. The specific natures of these interactions are poorly understood, in particular the role of microbes in facilitating mineralization and element cycling. Carbon isotope compositions of cap rock calcites (δ13Ccarb) are highly variable and range from near neutral to less than -40‰ (VPDB) indicative of methane-sourced carbon. These low values and the common coexistence of elemental sulfur and metal sulfides have spurred hypotheses invoking microbial sulfate reduction as driving carbonate mineral authigenesis. Here, we present new organic carbon isotope (δ13Corg) data that, similar to δ13Ccarb, exhibit depletions below -30 to -25‰. These δ13Corg values are lower than local liquid hydrocarbons and "normal" marine organic matter reflecting either microbial fixation of methane-sourced carbon or microbial fractionation from liquid hydrocarbon sources. The combined carbon isotope data (δ13Ccarb and δ13Corg) indicate that methane likely plays an important role in microbial cycling in salt domes. The δ13Corg values are similar to those of anaerobic oxidation of methane (AOM) related communities from methane-sulfate controlled marine sediments. Ultimately, salt dome environments may share some important characteristics with AOM systems.

  4. Living in Salt: The formation and development of extremophile habitats and biosignatures within salt crusts of the hyperarid Atacama Desert

    NASA Astrophysics Data System (ADS)

    Finstad, K. M.; Amundson, R.

    2013-12-01

    It has become increasing apparent that salt-rich deposits are present on the Martian surface and that aqueous alteration has occurred sometime during the planet's past. In the hyperarid Atacama Desert in Chile, an important Earth-based analogue to Mars, microbial life has been discovered inhabiting halite (NaCl) surface crust deposits. Is it possible that similar salt deposits on Mars once harbored microbial life? If so, what adaptations were likely necessary for survival in such an environment and what biosignatures are expected to remain? Although this fascinating ecosystem in the Atacama Desert has been recognized, neither the physical processes of halite crust formation, nor the microorganisms residing within the salts have been extensively studied. To better understand the formation and geochemical dynamics of this unique habitat, we chose two sites within the Atacama Desert which exhibit both active crust formation as well as the presence of microbial communities: one site is on a dry Holocene age lake bed, while the other is of Pleistocene age. At each site soil profiles were excavated and total geochemical analyses were performed. Field observations clearly showed that the soils exhibited transitions of carbonate to sulfate to chloride salt deposition with decreasing depth, and that the thickness and mass of halite in the surficial crust was related to the age of the soil. Isotope profiles of carbon, nitrogen, and sulfur from these soils were also analyzed. Once exposed to the atmosphere, the halite crusts reside in a dynamic state of dissolution and erosion by wind and fog, and reformation due to fog and dew. In the crust nodules, microbial communities were sampled, in centimeter increments from the surface, for carbon, nitrogen, and sulfur isotope/concentration profiles. Our analyses help elucidate the physical and geochemical processes linked to the formation and evolution of these dynamic salt crusts, and the imprint of microbial life within them. A

  5. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    PubMed

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. PMID:25445683

  6. Modelling of the reactive transport for rock salt-brine in geological repository systems based on improved thermodynamic database (Invited)

    NASA Astrophysics Data System (ADS)

    Müller, W.; Alkan, H.; Xie, M.; Moog, H.; Sonnenthal, E. L.

    2009-12-01

    for both Pitzer ion-interaction parameters and thermodynamic equilibrium constants. The reliability of the parameters is as important as the accuracy of the modelling tool. For this purpose the project THEREDA (www.thereda.de)was set up. The project aims at a comprehensive and internally consistent thermodynamic reference database for geochemical modelling of near and far-field processes occurring in repositories for radioactive wastes in various host rock formations. In the framework of the project all data necessary to perform thermodynamic equilibrium calculations for elevated temperature in the system of oceanic salts are under revision, and it is expected that related data will be available for download by 2010-03. In this paper the geochemical issues that can play an essential role for the transport of radioactive contaminants within and around waste repositories are discussed. Some generic calculations are given to illustrate the geochemical interactions and their probable effects on the transport properties around HLW emplacements and on CO2 generating and/or containing repository systems.

  7. Morphology and dynamics of explosive vents through cohesive rock formations

    NASA Astrophysics Data System (ADS)

    Galland, O.; Gisler, G. R.; Haug, Ø. T.

    2014-06-01

    Shallow explosive volcanic processes, such as kimberlite volcanism and phreatomagmatic and phreatic activity, produce volcanic vents exhibiting a wide variety of morphologies, including vertical pipes and V-shaped vents. In this study we report on experimental and numerical models designed to capture a range of vent morphologies in an eruptive system. Using dimensional analysis, we identified key governing dimensionless parameters, in particular the gravitational stress-to-fluid pressure ratio (Π2 = P/ρgh) and the fluid pressure-to-host rock strength ratio (Π3 = P/C). We used combined experimental and numerical models to test the effects of these parameters. The experiments were used to test the effect of Π2 on vent morphology and dynamics. A phase diagram demonstrates a separation between two distinct morphologies, with vertical structures occurring at high values of Π2 and diagonal ones at low values of Π2. The numerical simulations were used to test the effect of Π3 on vent morphology and dynamics. In the numerical models we see three distinct morphologies: vertical pipes are produced at high values of Π3, diagonal pipes at low values of Π3, and horizontal sills at intermediate values of Π3. Our results show that vertical pipes form by plasticity-dominated yielding in high-energy systems (high Π2 and Π3), whereas diagonal and horizontal vents dominantly form by fracturing in lower energy systems (low Π2 and Π3). Although our models are two-dimensional, they suggest that circular pipes result from plastic yielding of the host rock in a high-energy regime, whereas V-shaped volcanic vents result from fracturing of the host rock in lower energy systems.

  8. Optical and electron transport properties of rock-salt Sc1-xAlxN

    NASA Astrophysics Data System (ADS)

    Deng, Ruopeng; Zheng, P. Y.; Gall, D.

    2015-07-01

    Epitaxial single-crystal Sc1-xAlxN ternary alloy layers deposited by magnetron co-sputtering on MgO(001) substrates at 950 °C exhibit a solid solution rock-salt phase for x = 0-0.2 without decomposition. Optical absorption indicates a linear increase in the optical gap from 2.51 eV for ScN to 3.05 eV for Sc0.8Al0.2N and, after correction due to the Moss-Burstein shift, a direct X point interband transition energy Eg(X) = 2.15 + 2.75 x (eV). Correspondingly, the direct transition at the zone center increases with Al concentration according to Eg(Γ) = 3.80 + 1.45 x (eV), as determined from a feature in the reflection spectra. All layers are degenerate n-type semiconductors with a room temperature mobility that decreases from 22 to 6.7 to 0.83 cm2/V s as x increases from 0 to 0.11 to 0.20. The corresponding carrier densities are 9.2 × 1020, 7.9 × 1020, and 0.95 × 1020 cm-3 as determined from Hall measurements and consistent with optical free carrier absorption below photon energies of 1 eV. Temperature dependent transport measurements indicate metallic conduction for ScN, but weak localization that leads to a resistivity minimum at 85 and 210 K for x = 0.051 and 0.15, respectively, and a negative temperature coefficient over the entire measured 4-300 K range for Sc0.8Al0.2N. The decreasing mobility is attributed to alloy scattering at randomly distributed Al atoms on cation sites, which also cause the weak localization. The carrier density is primarily due to unintentional F doping from the Sc target and decreases strongly for x > 0.15, which is attributed to trapping in defect states due to the deterioration of the crystalline quality, as evidenced by the x-ray diffraction peak width that exhibits a minimum of 0.14° for x = 0.11 but increases to 0.49° for x = 0.20. This is consistent with asymmetric x-ray diffraction analyses, indicating a relaxed lattice constant that decreases from 4.511 ± 0.005 to 4.411 ± 0.004 Å for x = 0-0.2, and a biaxial in

  9. Measurement of radio wave reflection due to temperature rising from rock salt and ice irradiated by an electron beam for an ultra-high-energy neutrino detector

    SciTech Connect

    Tanikawa, Takahiro; Chiba, Masami; Kamijo, Toshio; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kon, Tadashi; Shimizu, Yutaka; Utsumi, Michiaki; Fujii, Masatoshi

    2012-11-12

    An ultra-high-energy neutrino (UHE{nu}) gives temperature rise along the hadronic and electromagnetic shower when it enters into rock salt or ice. Permittivities of them arise with respect the temperatures at ionization processes of the UHE{nu} shower. It is expected by Fresnel's formula that radio wave reflects at the irregularity of the permittivity in the medium. We had found the radio wave reflection effect in rock salt. The reflection effect and long attenuation length of radio wave in rock salt and ice would yield a new UHE{nu} detection method. An experiment for ice was performed to study the reflection effect. A coaxial tube was filled with rock salt powder or ice. Open end of the coaxial tube was irradiated by a 2 MeV electron beam. Radio wave of 435 MHz was introduced to the coaxial tube. We measured the reflection wave from the open end. We found the radio wave reflection effect due to electron beam irradiation in ice as well as in rock salt.

  10. Conceptual models of the formation of acid-rock drainage at road cuts in Tennessee

    USGS Publications Warehouse

    Bradley, Michael W.; Worland, Scott; Byl, Tom

    2015-01-01

    Pyrite and other minerals containing sulfur and trace metals occur in several rock formations throughout Middle and East Tennessee. Pyrite (FeS2) weathers in the presence of oxygen and water to form iron hydroxides and sulfuric acid. The weathering and interaction of the acid on the rocks and other minerals at road cuts can result in drainage with low pH (< 4) and high concentrations of trace metals. Acid-rock drainage can cause environmental problems and damage transportation infrastructure. The formation and remediation of acid-drainage from roads cuts has not been researched as thoroughly as acid-mine drainage. The U.S Geological Survey, in cooperation with the Tennessee Department of Transportation, is conducting an investigation to better understand the geologic, hydrologic, and biogeochemical factors that control acid formation at road cuts. Road cuts with the potential for acid-rock drainage were identifed and evaluated in Middle and East Tennessee. The pyrite-bearing formations evaluated were the Chattanooga Shale (Devonian black shale), the Fentress Formation (coal-bearing), and the Precambrian Anakeesta Formation and similar Precambrian rocks. Conceptual models of the formation and transport of acid-rock drainage (ARD) from road cuts were developed based on the results of a literature review, site reconnaissance, and the initial rock and water sampling. The formation of ARD requires a combination of hydrologic, geochemical, and microbial interactions which affect drainage from the site, acidity of the water, and trace metal concentrations. The basic modes of ARD formation from road cuts are; 1 - seeps and springs from pyrite-bearing formations and 2 - runoff over the face of a road cut in a pyrite-bearing formation. Depending on site conditions at road cuts, the basic modes of ARD formation can be altered and the additional modes of ARD formation are; 3 - runoff over and through piles of pyrite-bearing material, either from construction or breakdown

  11. Se EXAFS study of the elevated wurtzite to rock salt structural phase transition in CdSe nanocrystals

    SciTech Connect

    Tolbert, S.H.; Alivisatos, A.P. |

    1993-09-01

    High pressure Se EXAFS data has been obtained on 2.7 nm radius CdSe semiconductor nanocrystals. This system is observed to undergo a solid-solid phase transition at 6.5 GPa which is approximately twice the reported value for bulk CdSe. In combination with high pressure optical absorption experiments, EXAFS data can be used to identify the high-pressure phase structure as rock salt. EXAFS data can be fit with equations of state to yield pressure volume curves. Resultant values of bulk modulus and its derivative with respect to pressure are B{sub o} = 37 {plus_minus} 5 GPa and B{sub o}{prime} = 11 {plus_minus} 3. A thermodynamic model for the data is presented in which the internal energy in each phase is modified by a surface energy term. Differences in surface energy are used to explain the elevation in phase transition pressure. The model can be used to estimate a value for the surface energy in the rock salt phase; 1.9 {plus_minus} 0.3 N/m is obtained in comparison to 0.9 {plus_minus} 0. 1 N/m for the wurtzite phase.

  12. Silicate-carbonate-salt liquid immiscibility and origin of the sodalite-haüyne rocks: study of melt inclusions in olivine foidite from Vulture volcano, S. Italy

    NASA Astrophysics Data System (ADS)

    Panina, Liya; Stoppa, Francesco

    2009-12-01

    Melt inclusions in clinopyroxenes of olivine foidite bombs from Serra di Constantinopoli pyroclastic flows of the Vulture volcano (Southern Italy) were studied in detail. The rocks contain abundant zoned phenocrysts and xenocrysts of clinopyroxene, scarce grains of olivine, leucite, haüyne, glass with microlites of plagioclase and K-feldspar. The composition of clinopyroxene in xenocrysts (Cpx I), cores (Cpx II), and in rims (Cpx III) of phenocrysts differs in the content of Mg, Fe, Ti, and Al. All clinopyroxenes contain two types of primary inclusion-pure silicate and of silicate-carbonate-salt composition. This fact suggests that the phenomena of silicate-carbonate immiscibility took place prior to crystallization of clinopyroxene. Homogenization of pure silicate inclusions proceeded at 1 225 - 1 190°C. The composition of conserved melts corresponded to that of olivine foidite in Cpx I, to tephrite-phonolite in Cpx II, and phonolite-nepheline trachyte in Cpx III. The amount of water in them was no more than 0.9 wt.%. Silicate-carbonate inclusions decrepitated on heating. Salt globules contained salts of alkali-sulphate, alkali-carbonate, and Ca-carbonate composition somewhat enriched in Ba and Sr. This composition is typical of carbonatite melts when decomposed into immiscible fractions. The formation of sodalite-haüyne rocks from Vulture is related to the presence of carbonate-salt melts in magma chamber. The melts conserved in clinopyroxenes were enriched in incompatible elements, especially in Cpx III. High ratios of La, Nb, and Ta in melts on crystallization of Cpx I and Cpx II suggest the influence of a carbonatite melt as carbonatites have extremely high La/Nb and Nb/Ta and this is confirmed by the appearance of carbonatite melts in magma chamber. Some anomalies in the concentrations and relatives values of Eu and especially Ga seems typical of Italian carbonatite related melts. The mantle source for initial melts was, most likely, rather uniform

  13. NanoRocks: Studying Planet Formation and Planetary Rings on the International Space Station

    NASA Astrophysics Data System (ADS)

    Brisset, J.; Colwell, J.; Dove, A.; Maukonen, D.; Brown, N.; Lai, K.; Hoover, B.

    2015-10-01

    We report on the initial results of the NanoRocks experiment on the ISS, which simulates collisions in protoplanetary disks and planetary ring systems. The objective of the NanoRocks experiment is to study low-energy collisions inside systems of multiple mmsized particles of different shapes and materials. In September 2014, NanoRocks reached ISS as part of the NanoRacks platform. First video data from the experiment operations on ISS allows for the measurement of energy damping inside multi-particle systems and the observation of the formation of clusters.

  14. The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

    NASA Astrophysics Data System (ADS)

    Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

    2014-05-01

    Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and

  15. Organic geochemical characterization of reservoir rocks, cap rocks and formation fluids from the CO2 storage site at Ketzin, Germany

    NASA Astrophysics Data System (ADS)

    Scherf, A.-K.; Morozova, D.; Wandrey, M.; Mangelsdorf, K.; Würdemann, H.; Vieth, A.

    2009-04-01

    The European project CO2SINK (CO2 Storage by Injection into a natural saline Aquifer at Ketzin) is the first project on the on-shore underground storage of carbon dioxide in Europe. Near the city Ketzin (north-east Germany) a geological formation of the younger Triassic (Stuttgart Formation) was chosen as reservoir for the long-term storage of the carbon dioxide. Within the scope of the Ketzin project we will analyse the organic matter in core rock and fluid samples to investigate the biogeochemical effects and changes on the geological formation caused by the injection of carbon dioxide. These investigations will help to evaluate the efficiency and reliability of the long-term storage of CO2 in such a geological system. Organic geochemical analyses will be performed on core rock samples drilled in 2007 at the Ketzin CO2 storage site in Germany. In total, three bore holes were constructed: one injection well and two observation wells. In addition to the molecular analysis of the microbial community we will investigate rock samples from different depths for total, dissolved and extractable organic carbon including lipid biomarkers, such as organic acids and intact polar lipids as well as the isotopic analysis of individual organic compounds. With the analysis of intact phospholipids (IPL) we will be able to further characterize the indigenous microbial community. Intact phospholipids are found in all living cells as membrane components (Zelles, 1999). Their interpretation is based on the premise that different microorganisms contain different phospholipids with ester- and/or ether-bound fatty acids (White et al., 1979) and thus, the distribution of IPLs and PLFAs (phospholipids fatty acid) can be applied to characterise and compare microbial communities. The data obtained from these analyses will provide valuable information on the active microorganisms as well as shifts in community composition. The characterization of the organic matter in the reservoir rock

  16. Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine via diastereomeric salt formation.

    PubMed

    Kodama, Koichi; Kimura, Yuria; Shitara, Hiroaki; Yasutake, Mikio; Sakurai, Rumiko; Hirose, Takuji

    2011-04-01

    Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine 1 by N-(p-toluenesulfonyl)-(S)-phenylalanine 2 via diastereomeric salt formation was studied. (S)-1·(S)-2 was preferentially crystallized as a less-soluble salt from aqueous alcohol, while (R)-1·(S)-2 salt was mainly obtained by addition of solvents with a six-membered ring such as dioxane, cyclohexane, tetrahydropyran, and cyclohexene to 2-propanol. Further investigations were carried out from the viewpoints of molecular structures, optical rotation measurement, and X-ray crystallographic analyses. Crystallographic analyses have revealed that incorporation of the six-membered ring solvent molecule in (R)-1·(S)-2 without hydrogen bonds changed the molecular conformation of (S)-2 to stabilize the salt, which changed the selectivity of 1 in the enantioseparation. PMID:21384437

  17. Integrated system for investigating sub-surface features of a rock formation

    DOEpatents

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

  18. Kinetic Controls on Formation of Textures in Rapidly Cooled Rocks

    NASA Technical Reports Server (NTRS)

    Lofgren, Gary E.

    2006-01-01

    The crystallization of silicate melts is a complex process involving melts usually produced by partial melting and cooling environments that are rapid in volcanic lavas or so slow as to be auto-metamorphic in plutonic regimes. The volcanic lavas are amenable to laboratory study as are chondrules that comprise the bulk of chondritic meteorites. Dynamic crystallization studies of basalt and chondrule melts have shown that nucleation has a more profound effect on the final texture than the cooling or crystal growth rates. The sequence of crystal shapes grown at increasing degrees of supercooling (DELTA T) or cooling rate demonstrates the effect of increasing growth rate. Equant or euhedral crystals become skeletal, then dendritic and ultimately spherulitic indicating the nucleation temperature and the DELTA T when growth began. Because crystals cannot grow until they nucleate, cooling rate does not always correlate with crystal growth rate and thus crystal shape. Silicate melts cooled at the same rate can have drastically different textures depending on the temperature of nucleation. A dynamic crystallization study of basaltic rocks shows that basaltic lavas must erupt with sufficient crystals present in the melt to act as nuclei and foster growth. With nuclei present, growth will begin when the temperature drops below the liquidus temperature and typical basaltic textures such as intersertal, intergranular or subophitic will form. If nuclei are not present, crystallization will not begin immediately and the DELTA T will increase until embryos in the melts become nuclei. The DELTA T present when grow begins dictates the growth rate and the crystal shapes and thus the rock texture. If nucleation is delayed, growth will take place at high DELTA T and the crystals will favor skeletal or dendritic shapes. Chondrules are usually considered crystallized melt droplets and clearly some are, but most are not. Most chondrules have porphyritic textures that cannot develop from

  19. Why Hofmeister effects of many salts favor protein folding but not DNA helix formation

    PubMed Central

    Pegram, Laurel M.; Wendorff, Timothy; Erdmann, Robert; Shkel, Irina; Bellissimo, Dana; Felitsky, Daniel J.; Record, M. Thomas

    2010-01-01

    The majority (∼70%) of surface buried in protein folding is hydrocarbon, whereas in DNA helix formation, the majority (∼65%) of surface buried is relatively polar nitrogen and oxygen. Our previous quantification of salt exclusion from hydrocarbon (C) accessible surface area (ASA) and accumulation at amide nitrogen (N) and oxygen (O) ASA leads to a prediction of very different Hofmeister effects on processes that bury mostly polar (N, O) surface compared to the range of effects commonly observed for processes that bury mainly nonpolar (C) surface, e.g., micelle formation and protein folding. Here we quantify the effects of salts on folding of the monomeric DNA binding domain (DBD) of lac repressor (lac DBD) and on formation of an oligomeric DNA duplex. In accord with this prediction, no salt investigated has a stabilizing Hofmeister effect on DNA helix formation. Our ASA-based analyses of model compound data and estimates of the surface area buried in protein folding and DNA helix formation allow us to predict Hofmeister effects on these processes. We observe semiquantitative to quantitative agreement between these predictions and the experimental values, obtained from a novel separation of coulombic and Hofmeister effects. Possible explanations of deviations, including salt-dependent unfolded ensembles and interactions with other types of surface, are discussed. PMID:20385834

  20. Widespread evidences of hoarfrost formation at a rock glacier in the Seckauer Tauern, Austria

    NASA Astrophysics Data System (ADS)

    Kellerer-Pirklbauer, A.; Winkler, G.; Pauritsch, M.

    2012-04-01

    The mechanism of deep reversible air circulation (the so called "chimney effect" or "wind tube") is known to be a process of ground overcooling in the lower and deeper parts of porous sediments and related landforms such as scree slopes or intact and relict rock glaciers. Warm air outflow emerging from relatively small voids within these mostly coarse-grained sediment bodies is sometimes noticeable. However, easier to identify are associated phenomena such as snowmelt windows, snow cover depressions and hoarfrost formations. Generally, these indications for warm air outflow are found at the upper part of scree slopes or the rooting zone of rock glaciers. Here we present widespread field evidences of hoarfrost from the pseudo-relict Schöneben Rock Glacier in the Seckauer Tauern Range, Austria located at E14°40'26'' and N47°22'31''. Herewith, a pseudo-relict rock glacier is defined as an intermediate rock glacier type between a relict and a climatic-inactive rock glacier, hence a relict rock glacier with locally isolated patches of permafrost. The rock glacier covers an area of about 0.11km2, ranges from ca. 1720 to 1905 m a.s.l., and consists predominantly of coarse-grained gneissic sediments with blocks up to a size of several cubic metres at the surface. In particular the lower part and some ridges in the central and upper part are covered by dwarf pines (pinus mugo) mirroring the flow structure of the previously active rock glacier. Isolated permafrost occurs presumably at the rooting zone of the rock glacier as indicated by evidences from a neighbouring rock glacier in a comparable setting. Field observations in November 2011 showed widespread occurrences of hoarfrost crystals growing around the funnel edge indicating the sublimation of vapour from warm funnels. Such hoarfrost sites were found at more than 50 single locations distributed over the entire rock glacier from the tongue to the rooting zone generally. The occurrence of hoarfrost can get classified

  1. Impurities in rock-salt: consequences for the temperature increases at the disposal of high-level nuclear waste. [Kainite, Kieserite

    SciTech Connect

    van den Broek, W.M.G.T.

    1982-06-01

    In part A the thermal properties of halite and the other materials occurring in rock-salt (the 'impurities') are collected. Except for sylvite (the specific heat of this salt is about 70% of the value for halite) all specific heats are larger than the specific heat of halite. The consequences for the temperature increases at the disposal of high-level nuclear waste in rock-salt are discussed for impurity concentrations of 1, 5, 10 and 15%. If the presence and distribution of the impurities are not taken into account, then - under the most unfavorable conditions - extra temperature increases of about 3% per cent impurity may occur. If, however, the geological composition and its geometry for the disposal region are known, the temperature increases can be calculated more accurately: they may or may not differ from those for pure halite. In part B the measurement of the thermal conductivity for four salts (kainite, kieserite, carnallite, and polyhalite) is described.

  2. The formation of a yield-surface vertex in rock

    SciTech Connect

    Olsson, W.A.

    1992-01-01

    Microstructural models of deformation of polycrystalline materials suggest that inelastic deformation leads to the formation of a corner or vertex at the current load point. This vertex can cause the response to non-proportional loading to be more compliant than predicted by the smooth yield-surface idealization. Combined compression-torsion experiments on Tennessee marble indicate that a vertex forms during inelastic flow. An important implication is that strain localization by bifurcation occurs earlier than predicted by bifurcation analysis using isotropic hardening.

  3. Thermo-hydro-mechanical processes in fractured rock formations during a glacial advance

    NASA Astrophysics Data System (ADS)

    Selvadurai, A. P. S.; Suvorov, A. P.; Selvadurai, P. A.

    2015-07-01

    The paper examines the coupled thermo-hydro-mechanical (THM) processes that develop in a fractured rock region within a fluid-saturated rock mass due to loads imposed by an advancing glacier. This scenario needs to be examined in order to assess the suitability of potential sites for the location of deep geologic repositories for the storage of high-level nuclear waste. The THM processes are examined using a computational multiphysics approach that takes into account thermo-poroelasticity of the intact geological formation and the presence of a system of sessile but hydraulically interacting fractures (fracture zones). The modelling considers coupled thermo-hydro-mechanical effects in both the intact rock and the fracture zones due to contact normal stresses and fluid pressure at the base of the advancing glacier. Computational modelling provides an assessment of the role of fractures in modifying the pore pressure generation within the entire rock mass.

  4. Thermo-hydro-mechanical processes in fractured rock formations during glacial advance

    NASA Astrophysics Data System (ADS)

    Selvadurai, A. P. S.; Suvorov, A. P.; Selvadurai, P. A.

    2014-11-01

    The paper examines the coupled thermo-hydro-mechanical (THM) processes that develop in a fractured rock region within a fluid-saturated rock mass due to loads imposed by an advancing glacier. This scenario needs to be examined in order to assess the suitability of potential sites for the location of deep geologic repositories for the storage of high-level nuclear waste. The THM processes are examined using a computational multiphysics approach that takes into account thermo-poroelasticity of the intact geological formation and the presence of a system of sessile but hydraulically interacting fractures (fracture zones). The modeling considers coupled thermo-hydro-mechanical effects in both the intact rock and the fracture zones due to contact normal stresses and fluid pressure at the base of the advancing glacier. Computational modelling provides an assessment of the role of fractures that can modify the pore pressure generation within the entire rock mass.

  5. Zinc-blende to rock-salt structural phase transition of BP and BAs under high pressure

    NASA Astrophysics Data System (ADS)

    Sarwan, Madhu; Bhardwaj, Purvee; Singh, Sadhna

    2013-11-01

    In the present paper, we have investigated the pressure induced phase transition and thermophysical properties of BP and BAs by means of modified interaction potential model (MIPM). The MIPM consists of Coulomb interaction, three-body interaction (TBI) modified by taking covalency effect, van-der Waal interaction (vdW), short range overlap repulsive interaction and zero point energy effect. These compounds crystallize in zinc-blende (ZB) structure at ambient condition and transform to rock-salt (RS) structure at pressures 111 and 93 GPa and their equation of state show volume collapse of 14% and 4% respectively for BP and BAs. The second order elastic constants have also been computed at zero and high pressures. Our results are in good agreement with the experimental results. The mechanical and thermophysical properties in ZB structure are also predicted.

  6. Testing the role of silicic acid and bioorganic materials in the formation of rock coatings

    NASA Astrophysics Data System (ADS)

    Kolb, Vera M.; Philip, Ajish I.; Perry, Randall S.

    2004-11-01

    Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which the rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of the polymerization of silicic acid with the biooganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the natural ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly on Mars.

  7. Testing the Role of Silicic Acid and Bioorganic Materials in the Formation of Rock Coatings

    SciTech Connect

    Kolb, Vera; Philip, Ajish I.; Perry, Randall S.

    2004-12-01

    Silica, amino acids, and DNA were recently discovered in desert varnish. In this work we experimentally test the proposed role of silicic acid and bio-chemicals in the formation of desert varnish and other rock coatings. We have developed a protocol in which hte rocks were treated with a mixture of silicic acid, sugars, amino acids, metals and clays, under the influence of heat and UV light. This protocol reflects the proposed mechanism of hte polymerization of silicic acid with the bioorganic materials, and the laboratory model for the natural conditions under which the desert varnish is formed. Our experiments produced coatings with a hardness and morphology that resemble the nature ones. These results provide a support for the role of silicic acid in the formation of rock coatings. Since the hard silica-based coatings preserve organic compounds in them, they may serve as a biosignature for life, here or possibly Mars.

  8. Self-assembly of ordered wurtzite/rock salt heterostructures—A new view on phase separation in Mg{sub x}Zn{sub 1−x}O

    SciTech Connect

    Gries, K. I.; Vogel, S.; Straubinger, R.; Beyer, A.; Chernikov, A.; Chatterjee, S.; Volz, K.; Wassner, T. A.; Bruckbauer, J.; Häusler, I.; Laumer, B.; Kracht, M.; Heiliger, C.; Eickhoff, M.; Janek, J.

    2015-07-28

    The self-assembled formation of ordered, vertically stacked rocksalt/wurtzite Mg{sub x}Zn{sub 1−x}O heterostructures by planar phase separation is shown. These heterostructures form quasi “natural” two-dimensional hetero-interfaces between the different phases upon annealing of MgO-oversaturated wurtzite Mg{sub x}Zn{sub 1−x}O layers grown by plasma-assisted molecular beam epitaxy on c-plane sapphire substrates. The optical absorption spectra show a red shift simultaneous with the appearance of a cubic phase upon annealing at temperatures between 900 °C and 1000 °C. Transmission electron microscopy reveals that these effects are caused by phase separation leading to the formation of a vertically ordered rock salt/wurtzite heterostructures. To explain these observations, we suggest a phase separation epitaxy model that considers this process being initiated by the formation of a cubic (Mg,Zn)Al{sub 2}O{sub 4} spinel layer at the interface to the sapphire substrate, acting as a planar seed for the epitaxial precipitation of rock salt Mg{sub x}Zn{sub 1−x}O. The equilibrium fraction x of magnesium in the resulting wurtzite (rock salt) layers is approximately 0.15 (0.85), independent of the MgO content of the as-grown layer and determined by the annealing temperature. This model is confirmed by photoluminescence analysis of the resulting layer systems after different annealing temperatures. In addition, we show that the thermal annealing process results in a significant reduction in the density of edge- and screw-type dislocations, providing the possibility to fabricate high quality templates for quasi-homoepitaxial growth.

  9. Energy-polarization behaviors of AA'BB'O6 perovskites with double rock-salt order

    NASA Astrophysics Data System (ADS)

    Roy, Anindya; Vanderbilt, David

    2010-03-01

    Using first-principles methods, we study the energy-polarization relation of double perovskites AA'BB'O6 where atoms in both A and B sites are arranged in rock-salt order. The high-symmetry structure in this case is the tetrahedral F43m space group. If a ferroelectric instability occurs, the energy-vs.-polarization landscape E(P) will tend to have minima for P along tetrahedral directions leading to a rhombohedral space group R3m, with two different values of spontaneous polarization and associated energy along opposite body-diagonal directions; or along Cartesian directions, leading to orthorhombic space group Imm2. We search for polar soft modes at the γ point of the high-symmetry F43m structure and analyze its eigenvectors to identify ferroelectric instabilities, which we find in CaBaTiZrO6, KCaZrNbO6 and PbSnTiZrO6. The results of the first-principle calculations are modeled with a Landau-Devonshire expansion that is truncated at either 4th or 5th order in P, and its predictions are found to agree favorably with our calculation. The 5th-order calculation improves the agreement further except in PSTZ. Recently, synthesis of SrCaTiMnO6 in rock-salt order has been reported.footnotetextJ.L Blok, G. Rijnders and D.H.A. Blank, private communication. Unfortunately, preliminary results do not seem to indicate any polarized structure.

  10. Salt and mesophase formation in aqueous suspensions of lauric acid.

    PubMed

    Smith, S W; Anderson, B D

    1993-10-01

    The solubility and solution behavior of lauric acid (LA) and its 1:1 acid soap (potassium hydrogen dilaurate) were investigated at 32 degrees C over a pH range of 2.5-8.5 and at varying KCl concentrations to examine the self-association of this long-chain carboxylic acid under these conditions. LA's solubility in water exhibited the classical pH dependence of a monocarboxylic acid with no evidence of self-association. In 0.1 M KCl between pH 6.3 and pH 7.3, filtered samples were turbid, suggesting the presence of high molecular weight aggregates (mesophase), which could be removed by ultrafiltration. The apparent LA solubility vs pH profile in ultrafiltered samples was consistent with a solid phase consisting of either the free acid (pH < 6.5) or potassium hydrogen dilaurate (pH > 6.5), again with no evidence of self-association to form low molecular weight species (dimers, etc.). Quasi-elastic light scattering (QLS) studies and mannitol trapping experiments indicated that vesicles were present in samples containing mesophase. The mesophase composition was characterized and a mass-action law for mesophase formation was developed to describe the apparent LA solubility versus pH in the mesophase region in terms of three parameters. The index of cooperativity, theta, indicated that the mesophase consists of approximately 25 molecules of LA with an acid:anion ratio, rho, of 1.7. The standard free energy of mesophase formation per mole of monomer was determined to be -6.3 kcal/mol. The aggregate size determined thermodynamically is several orders of magnitude less than that of the mesophase particle size determined by QLS measurements, suggesting that the LA monomer concentration in equilibrium with mesophase may be governed by a small unit domain of the vesicle. These observations may have a bearing on the thermodynamics of self-assembly of lipid bilayer membranes. PMID:8272419

  11. Chapter 5. Assessment of undiscovered conventional oil and gas resources-Lower Cretaceous Travis Peak and Hosston formations, Jurassic Smackover interior salt basins total petroleum system, in the East Texas basin and Louisiana-Mississippi salt basins provinces.

    USGS Publications Warehouse

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

    2006-01-01

    The petroleum assessment of the Travis Peak and Hosston Formations was conducted by using a total petroleum system model. A total petroleum system includes all of the important elements of a hydrocarbon fluid system needed to develop oil and gas accumulations, including source and reservoir rocks, hydrocarbon generation, migration, traps and seals, and undiscovered accumulations. A total petroleum system is mappable and may include one or more assessment units. For each assessment unit, reservoir rocks contain similar geology, exploration characteristics, and risk. The Jurassic Smackover Interior Salt Basins Total Petroleum System is defined for this assessment to include (1) Upper Jurassic Smackover carbonates and calcareous shales and organic-rich shales of the Upper Jurassic Bossier Shale of the Cotton Valley Group and (2) Lower Cretaceous Travis Peak and Hosston Formations. The Jurassic Smackover Interior Salt Basins Total Petroleum System includes three conventional Travis Peak-Hosston assessment units: Travis Peak-Hosston Gas and Oil (AU 50490205), Travis Peak-Hosston Updip Oil (AU 50490206), and Travis Peak-Hosston Hypothetical Updip Oil (AU 50490207). A fourth assessment unit, the Hosston Hypothetical Slope-Basin Gas Assessment Unit, was named and numbered (AU 50490208) but not geologically defined or quantitatively assessed owing to a lack of data. Together, assessment units 50490205 to 50490207 are estimated to contain a mean undiscovered conventional resource of 29 million barrels of oil, 1,136 billion cubic feet of gas, and 22 million barrels of natural gas liquids.

  12. Effect of Salt Concentration on the Pattern Formation of Colloidal Suspension

    NASA Astrophysics Data System (ADS)

    Ma, Wenjie; Wang, Yuren

    We study the effect of salt concentration on the drying process and pattern of thin liquid layer colloidal suspension. Panasonic camera is used to capture the drying process and macroscopic pattern. Microscopic patterns are analyzed by optical microscopy. It is shown that broad-ring pattern is avoided by adding little amount of sodium chloide into colloidal suspension. with the increase of salt concentraion, convection strength and interface instability are weakened, thus the edge of film becomes smooth and more homogeneous film forms. Beautiful microscopic patterns demonstrate that the cooperative interaction between sodium chloide and silica spheres has important influence on the pattern formation.

  13. Salt deposits in Los Medanos area, Eddy and Lea counties, New Mexico

    USGS Publications Warehouse

    Jones, C.L.; with sections on Ground water hydrology, Cooley, Maurice E.; and Surficial Geology, Bachman, George Odell

    1973-01-01

    The salt deposits of Los Medanos area, in Eddy and Lea Counties, southeastern New Mexico, are being considered for possible use as a receptacle for radioactive wastes in a pilot-plant repository. The salt deposits of the area. are in three evaporite formations: the Castile, Salado, and Rustler Formations, in ascending order. The three formations are dominantly anhydrite and rock salt, but some gypsum, potassium ores, carbonate rock, and fine-grained clastic rocks are present. They have combined thicknesses of slightly more than 4,000 feet, of which roughly one-half belongs to the Salado. Both the Castile and the Rustler are-richer in anhydrite-and poorer in rock salt-than the Salado, and they provide this salt-rich formation with considerable Protection from any fluids which might be present in underlying or overlying rocks. The Salado Formation contains many thick seams of rock salt at moderate depths below the surface. The rock salt has a substantial cover of well-consolidated rocks, and it is very little deformed structurally. Certain geological details essential for Waste-storage purposes are unknown or poorly known, and additional study involving drilling is required to identify seams of rock salt suitable for storage purposes and to establish critical details of their chemistry, stratigraphy, and structure.

  14. Preparation of Al-Si Master Alloy by Electrochemical Reduction of Volcanic Rock in Cryolite Molten Salt

    NASA Astrophysics Data System (ADS)

    Liu, Aimin; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2016-04-01

    Volcanic rock found in the Longgang Volcano Group in Jilin Province of China has properties essentially similar to Apollo lunar soils and previously prepared lunar soil simulants, such as Johnson Space Center Lunar simulant and Minnesota Lunar simulant. In this study, an electrochemical method of preparation of Al-Si master alloy was investigated in 52.7 wt.%NaF-47.3 wt.%AlF3 melt adding 5 wt.% volcanic rock at 1233 K. The cathodic electrochemical process was studied by cyclic voltammetry, and the results showed that the cathodic reduction of Si(IV) is a two-step reversible diffusion-controlled reaction. Si(IV) is reduced to Si(II) by two electron transfers at -1.05 V versus platinum quasi-reference electrode in 52.7 wt.%NaF-47.3 wt.%AlF3 molten salt adding 5 wt.% volcanic rock, while the reduction peak at -1.18 V was the co-deposition of aluminum and silicon. In addition, the cathodic product obtained by galvanostatic electrolysis for 4 h was analyzed by means of x-ray diffraction, x-ray fluorescence, scanning electron microscopy and energy dispersive spectrometry. The results showed that the phase compositions of the products are Al, Si, Al5FeSi, and Al3.21Si0.47, while the components are 90.5 wt.% aluminum, 4.4 wt.% silicon, 1.9 wt.% iron, and 0.2 wt.% titanium.

  15. Preparation of Al-Si Master Alloy by Electrochemical Reduction of Volcanic Rock in Cryolite Molten Salt

    NASA Astrophysics Data System (ADS)

    Liu, Aimin; Shi, Zhongning; Xu, Junli; Hu, Xianwei; Gao, Bingliang; Wang, Zhaowen

    2016-06-01

    Volcanic rock found in the Longgang Volcano Group in Jilin Province of China has properties essentially similar to Apollo lunar soils and previously prepared lunar soil simulants, such as Johnson Space Center Lunar simulant and Minnesota Lunar simulant. In this study, an electrochemical method of preparation of Al-Si master alloy was investigated in 52.7 wt.%NaF-47.3 wt.%AlF3 melt adding 5 wt.% volcanic rock at 1233 K. The cathodic electrochemical process was studied by cyclic voltammetry, and the results showed that the cathodic reduction of Si(IV) is a two-step reversible diffusion-controlled reaction. Si(IV) is reduced to Si(II) by two electron transfers at -1.05 V versus platinum quasi-reference electrode in 52.7 wt.%NaF-47.3 wt.%AlF3 molten salt adding 5 wt.% volcanic rock, while the reduction peak at -1.18 V was the co-deposition of aluminum and silicon. In addition, the cathodic product obtained by galvanostatic electrolysis for 4 h was analyzed by means of x-ray diffraction, x-ray fluorescence, scanning electron microscopy and energy dispersive spectrometry. The results showed that the phase compositions of the products are Al, Si, Al5FeSi, and Al3.21Si0.47, while the components are 90.5 wt.% aluminum, 4.4 wt.% silicon, 1.9 wt.% iron, and 0.2 wt.% titanium.

  16. Radioactivity of a Rock Profile from Rio do Rasto Formation Measured by High Resolution Gamma Spectrometry

    NASA Astrophysics Data System (ADS)

    Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, José P. P.

    2011-08-01

    Natural occurring radionuclides are present in different concentrations in sedimentary rocks. Generally, their distribution correlates reasonably with their geo-physicochemical behavior during sediment deposition and rock consolidation. This fact permits to study some geological characteristics of the rocks by analyzing the radionuclide distribution in the rocks, as it might reflect the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. In this work, rocks from an exposed profile of the Rio do Rasto Formation were collected and analyzed in laboratory by high resolution gamma spectrometry for 226Ra, 232Th and 40K determination. It was employed a standard gamma ray spectrometry electronic chain, with a 66% relative efficiency HPGe detector. The efficiency calibration, as well as its validation, was accomplished with eight International Atomic Energy Agency certified samples. The outcrop exposes layers of sandstone and siltstone and, secondarily, claystone, with varying colors (gray, red and green). The rocks were collected along this profile, each of them was dried in the open air during 48 hours, grounded, sieved through 4 mm mesh and sealed in cylindrical recipients. The 226Ra, 232Th and 40K activity concentrations are presented, their distribution and the possible relations among activities are analyzed. The general pattern of radionuclides distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  17. Molten salt as a heat transfer fluid for heating a subsurface formation

    DOEpatents

    Nguyen, Scott Vinh; Vinegar, Harold J.

    2010-11-16

    A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

  18. Rock Abrasion and Ventifact Formation on Mars from Field Analog, Theoretical, and Experimental Studies

    NASA Technical Reports Server (NTRS)

    Bridges, N. T.; Laity, J. E.

    2001-01-01

    Rocks observed by the Viking Landers and Pathfinder Lander/Sojourner rover exhibit a suite of perplexing rock textures. Among these are pits, spongy textures, penetrative flutes, lineaments, crusts, and knobs Fluvial, impact, chemical alteration, and aeolian mechanisms have been proposed for many of these. In an effort to better understand the origin and characteristics of Martian rock textures, abraded rocks in the Mojave Desert and other regions have been studied. We find that most Martian rock textures, as opposed to just a few, bear close resemblance to terrestrial aeolian textures and can most easily be explained by wind, not other, processes. Flutes, grooves, and some pits on Mars are consistent with abrasion by saltating particles, as described previously. However, many other rock textures probably also have an aeolian origin. Sills at the base of rocks that generally lie at high elevations, such as Half Dome, are consistent with such features on Earth that are related to moats or soil ramps that shield the basal part of the rock from erosion. Crusts consisting of fluted fabrics, such as those on Stimpy and Chimp, are similar to fluted crusts on Earth that spall off over time. Knobby and lineated rocks are similar to terrestrial examples of heterogeneous rocks that differentially erode. The location of specific rock textures on Mars also gives insight into their origin. Many of the most diagnostic ventifacts found at the Pathfinder site are located on rocks that lie near the crests or the upper slopes of ridges. On Earth, the most active ventifact formation occurs on sloped or elevated topography, where windflow is accelerated and particle kinetic energy and flux are increased. Integrated 0 together, these observations point to significant aeolian 0 modification of rocks on Mars and cast doubt on whether many primary textures resulting from other processes are preserved. Experimental simulations of abrasion in the presence of abundant sand indicate that

  19. Composite grain size sensitive and grain size insensitive creep of bischofite, carnallite and mixed bischofite-carnallite-halite salt rock

    NASA Astrophysics Data System (ADS)

    Muhammad, Nawaz; de Bresser, Hans; Peach, Colin; Spiers, Chris

    2016-04-01

    Deformation experiments have been conducted on rock samples of the valuable magnesium and potassium salts bischofite and carnallite, and on mixed bischofite-carnallite-halite rocks. The samples have been machined from a natural core from the northern part of the Netherlands. Main aim was to produce constitutive flow laws that can be applied at the in situ conditions that hold in the undissolved wall rock of caverns resulting from solution mining. The experiments were triaxial compression tests carried out at true in situ conditions of 70° C temperature and 40 MPa confining pressure. A typical experiment consisted of a few steps at constant strain rate, in the range 10‑5 to 10‑8 s‑1, interrupted by periods of stress relaxation. During the constant strain rate part of the test, the sample was deformed until a steady (or near steady) state of stress was reached. This usually required about 2-4% of shortening. Then the piston was arrested and the stress on the sample was allowed to relax until the diminishing force on the sample reached the limits of the load cell resolution, usually at a strain rate in the order of 10‑9 s‑1. The duration of each relaxation step was a few days. Carnallite was found to be 4-5 times stronger than bischofite. The bischofite-carnallite-halite mixtures, at their turn, were stronger than carnallite, and hence substantially stronger than pure bischofite. For bischofite as well as carnallite, we observed that during stress relaxation, the stress exponent nof a conventional power law changed from ˜5 at strain rate 10‑5 s‑1 to ˜1 at 10‑9 s‑1. The absolute strength of both materials remained higher if relaxation started at a higher stress, i.e. at a faster strain rate. We interpret this as indicating a difference in microstructure at the initiation of the relaxation, notably a smaller grain size related to dynamical recrystallization during the constant strain rate step. The data thus suggest that there is a gradual change in

  20. Lichen-rock interaction in volcanic environments: evidences of soil-precursor formation

    NASA Astrophysics Data System (ADS)

    Vingiani, S.; Adamo, P.; Terribile, F.

    2012-04-01

    The weathering action of the lichens Lecidea fuscoatra (L.) Ach. and Stereocaulon vesuvianum Pers. on basaltic rock collected on the slopes of Mt. Etna (Sicily) at 1550 m a.s.l. has been studied using optical (OM) and electron (SEM) microscopy equipped with microanalytical device (EDS). Biological factors associated with lichen growth play a major role in the weathering of minerals on bare rocks and contribute to the preliminary phases of soil formation. The present work investigates the biogeophysical and biogeochemical weathering associated to the growth of epilithic lichens on lava flows from Mt. Etna (Sicily) and Mt. Vesuvius (Campania). The chosen lichen species were the crustose Lecidea fuscoatra (L.) Ach., the foliose Xanthoparmelia conspersa and the fructicose Stereocaulon vesuvianum Pers. An integrated approach based on the study of both disturbed and undisturbed samples of lichenized rock was applied in order to appreciate the complexity of the rock-lichen interface environment in terms of micromorphological, mineralogical and chemical properties. XRD and XRF analyses coupled to microscopical (OM), submicroscopical (SEM) and microanalitical (EDS) observations were the used techniques. In both study environments, the chemical, mineralogical and micromorphological properties of the uncoherent materials found at the lichen-rock interface suggest they consist of rock fragments eroded from the surroundings and accumulated in cavities and fissures of the rough lava flows. According to the thallus morphology, the lichens colonizing the lava preserve the interface materials from further aeolic and water erosion, provide these materials of organic matter and moisture, entrap allochtonous quartz and clay minerals. The calcium oxalate production by L. fuscoatra and X. conspersa, the Al enrichment around S. vesuvianum hyphae and the occurrence of Fe-oxide phases at the rock-lichen interface are evidences of lichens interaction with the underlying sediments. Indeed

  1. Palaeomagnetic constraints on formation of the Mianwali reentrant, Trans-Indus and western Salt Range, Pakistan

    NASA Astrophysics Data System (ADS)

    Klootwijk, Chris T.; Nazirullah, Russell; de Jong, Kees A.

    1986-11-01

    Successions of Lower to lower Middle Cambrian, Upper Permian to Upper Triassic and Lower Tertiary carbonates and arenites have been sampled in five sections, representative of the three main segments of the Mianwali reentrant in the (Trans-Indus) Salt Range (northern Pakistan), i.e.: the southern Khisor Range, the northern Surghar Range and the western Salt Range. Comparison of primary and secondary magnetization directions with the Indian APWP demonstrates the secondary origin of the Mianwali reentrant and shows a pattern of rotations which varies in sense and magnitude along the reentrant with the main structural trends. Data from the Trans-Indus and western Salt Range and published Early Cambrian, Early Permian and Late Tertiary palaeomagnetic results from the southern Salt Range and the Potwar Plateau show that the Hazara Arc underwent a 20-45° counterclockwise rotation relative to the Indian Shield. A contrasting clockwise rotation over about 45° has recently been established for thrust sheets in the opposing eastern limb of the Western Himalayan Syntaxis, i.e. for the Panjal Nappe [1] and the Riasi thrust sheet [2]. These palaeomagnetically established rotations conform with the about 75° azimuthal change in structural trend along the Syntaxis, and support Crawford's [3] suggestion that the Salt Range was originally in line with the northwestern Himalaya. The Salt Range front prograded and moved southwards as part of the Hazara Arc thrust sheet, detached from basement along the evaporitic Salt Range Formation. The Mianwali reentrant originated through obstruction of the southwards advancing thrust sheet by moulding around basement topography of the northwest oriented Sarghoda Ridge.

  2. Pattern formation of down-built salt structures: insights from 3D numerical models

    NASA Astrophysics Data System (ADS)

    Fernandez, Naiara; Kaus, Boris

    2015-04-01

    Many salt diapirs are thought to have formed as a result of down-building, which implies that the top of the diapir remained close to the surface during sediment deposition. This process is largely three-dimensional and in order to better understand what controls the patterns that form as a result of this down-building process, we here perform three-dimensional numerical models and compare the results with analytical models. In our models, we vary several parameters such as initial salt thickness, sedimentation rate, salt viscosity, salt-sediment viscosity contrast as well as the density of sediments. Down-building of three-dimensional diapirs only occurs for a certain range of parameters and is favored by lower sediment/salt viscosity contrasts and sedimentation rates in agreement with analytical predictions and findings from previous 2D models. However, the models show that the sedimentation rate has an additional effect on the formation and evolution of three-dimensional diapir patterns. At low sedimentation rates, salt ridges that form during early model stages remain preserved at later stages as well. For higher sedimentation rates, the initial salt ridges break up and form finger-like diapirs at the junction of salt ridges, which results in different salt exposure patterns at the surface. Once the initial pattern of diapirs is formed, higher sedimentation rate can also result in covered diapirs if the diapir extrusion velocity is insufficiently large. We quantify the effect of sedimentation rate on the number of diapirs exposed at the surface as well as on their spacing. In some cases, this final pattern is distinctly different from the initial polygonal pattern. We also study the extrusion of salt through time in the simulations, and show that it can be related to the geometries of the sedimentary layers surrounding the diapirs. Acknowledgements. Funding was provided by the European Research Council under the European Community's Seventh Framework Program

  3. Diamond formation due to a pH drop during fluid-rock interactions

    NASA Astrophysics Data System (ADS)

    Sverjensky, Dimitri A.; Huang, Fang

    2015-11-01

    Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water-silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water-rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly with eclogite at 900 °C and 5.0 GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water-rock interactions without changes in oxidation state.

  4. Diamond formation due to a pH drop during fluid–rock interactions

    PubMed Central

    Sverjensky, Dimitri A.; Huang, Fang

    2015-01-01

    Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water–silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water–rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly with eclogite at 900 °C and 5.0 GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water–rock interactions without changes in oxidation state. PMID:26529259

  5. Diamond formation due to a pH drop during fluid–rock interactions

    DOE PAGESBeta

    Sverjensky, Dimitri A.; Huang, Fang

    2015-11-03

    Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water–silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water–rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly withmore » eclogite at 900 °C and 5.0 GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water–rock interactions without changes in oxidation state.« less

  6. Diamond formation due to a pH drop during fluid–rock interactions

    SciTech Connect

    Sverjensky, Dimitri A.; Huang, Fang

    2015-11-03

    Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water–silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water–rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly with eclogite at 900 °C and 5.0 GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water–rock interactions without changes in oxidation state.

  7. Diamond formation due to a pH drop during fluid-rock interactions.

    PubMed

    Sverjensky, Dimitri A; Huang, Fang

    2015-01-01

    Diamond formation has typically been attributed to redox reactions during precipitation from fluids or magmas. Either the oxidation of methane or the reduction of carbon dioxide has been suggested, based on simplistic models of deep fluids consisting of mixtures of dissolved neutral gas molecules without consideration of aqueous ions. The role of pH changes associated with water-silicate rock interactions during diamond formation is unknown. Here we show that diamonds could form due to a drop in pH during water-rock interactions. We use a recent theoretical model of deep fluids that includes ions, to show that fluid can react irreversibly with eclogite at 900 °C and 5.0 GPa, generating diamond and secondary minerals due to a decrease in pH at almost constant oxygen fugacity. Overall, our results constitute a new quantitative theory of diamond formation as a consequence of the reaction of deep fluids with the rock types that they encounter during migration. Diamond can form in the deep Earth during water-rock interactions without changes in oxidation state. PMID:26529259

  8. Pyrite formation and the measurement of sulfate reduction in salt marsh sediments

    SciTech Connect

    Howarth, R.W.; Merkel, S.

    1984-05-01

    A new method was used to study the formation of pyrite plus elemental sulfur during /sup 35/SO/sub 4//sup 2 -/ reduction experiments in salt marsh sediments: the reduction with chromium(II) of pyrite and elemental sulfur to hydrogen sulfide. It is both more specific and more sensitive than the previous method, the oxidation of pyrite and elemental sulfur to sulfate by aqua regia, which measures the formation of refractory organic sulfur compounds as well as pyrite and elemental sulfur. A direct comparison of the two methods in salt marsh sediments in Georgia and in Massachusetts showed that they compare very well. The chromium(II) reduction method, combined with the authors' previous results, conclusively shows that pyrite is the major product of /sup 35/SO/sub 4//sup 2 -/ reduction measurements in these sediments. The agreement between the two methods indicates that the formation of /sup 35/S-labeled, refractory organic matter is a minor process if it occurs at all. The authors' results suggest that both the aqua regia oxidation method and the chromium(II) reduction method, if used with care, are suitable for measuring incorporation of /sup 35/S into pyrite and elemental sulfur during /sup 35/SO/sub 4//sup 2 -/ reduction measurements in salt marsh sediments. Failure to explicitly measure the formation of /sup 35/S-labeled pyrite can result in the rate of sulfate reduction being underestimated by 2-fold to 10-fold or more.

  9. Ooid formation in the Great Salt Lake, Utah: Insights from clumped isotope paleothermometry

    NASA Astrophysics Data System (ADS)

    Anderson, R. P.; Bird, J. T.; Meneske, M.; Stefurak, E. J.; Berelson, W.; Petryshyn, V. A.; Shapiro, R. S.; Sessions, A. L.; Tripati, A.; Corsetti, F. A.

    2013-12-01

    Ooids (coated grains formed in agitated environments) are a relatively common constituent of the sedimentary record through time, but details of their formation remain enigmatic. Although not as abundant today as at other times in the past, ooids are known from several key carbonate environments, including the Bahamas, Persian Gulf, Shark Bay, and the Great Salt Lake. We collected ooids from the Great Salt Lake in association with the International GeoBiology Summer Course in 2012 and 2013 from the north shore of Antelope Island and Spiral Jetty in order to investigate their origin. Petrographic investigation reveals the ooids are composed of aragonite, and display an alternating radial, concentric, and radial-concentric fabric. The delicate nature of the radial fabric is suggestive, but not conclusive, that they form currently (agitation would abrade the fabric). The nuclei are typically rod shaped micritic peloids (up to 80%) or siliciclastic mineral grains. The Great Salt Lake surface water temperature undergoes a predictable annual cycle, with summer months approaching 25 degrees C or more, and winter months dipping to 5 degrees C or less, depending on the region of the lake. Clumped isotope temperatures allow us to constrain ooid formation to the warm months. A contrast between the isotopic composition of the waters for Antelope Island (~0 per mill), likely affected by spring runoff, and the ooids of the same location (~4.5 per mill) further suggest ooid formation took place after the spring runoff, constraining ooid formation to between mid-June and October. We calculated the summer and winter carbonate saturation state of the lake, and while the lake is supersaturated throughout the year, it is significantly more saturated during the summer months. Our results give new insight into ooid formation in the Great Salt Lake, and suggest that the ooids form predominantly during the warm months following the spring runoff.

  10. Molecular dynamics studies of aqueous silica nanoparticle dispersions: salt effects on the double layer formation

    NASA Astrophysics Data System (ADS)

    de Lara, Lucas S.; Rigo, Vagner A.; Michelon, Mateus F.; Metin, Cigdem O.; Nguyen, Quoc P.; Miranda, Caetano R.

    2015-08-01

    The ion distribution around hydroxylated silica nanoparticles (NP-H) dispersed in brine was investigated by fully atomistic molecular dynamics. The NP-H dispersions in aqueous electrolyte media are simulated in solutions of varying salinity (NaCl, CaCl2, and MgCl2), salt concentration (0.06  ×  10-3 to 3.00  ×  10-3 mole fraction {χ\\text{s}} ), and temperature (300 and 350 K) at 1 atm. The NP-H models reproduce the observed experimental concentration of silanol and geminal surface sites, which are responsible for local charge variations on the nanoparticles’ surface. Interestingly, under certain salt concentration conditions, the formation of an electrical double layer (DL) around the overall neutral NP-H occurs. The resulting DLs are attenuated with increasing temperature for all evaluated salts. With increasing salt concentration, a sign inversion of the effective charge at the first ion layer is observed, which modifies the electrostatic environment around the nanoparticle. The minimum salt concentration that leads to a DL formation at 300 K is 1.05  ×  10-3, 0.37  ×  10-3, and 0.06  ×  10-3 {χ\\text{s}} for NaCl, CaCl2, and MgCl2, respectively. The width of the DL decreases sequentially in ionic strength from NaCl to CaCl2 to MgCl2, which is similar to that found for highly charged surfaces. These results are in line with our previous experimental data for negative charged NP-H. All together, these observations suggest an interplay mechanism between the formation and narrowing of electric double layers on the stability of NP dispersions in both neutral and negatively charged NP-H.

  11. Molecular dynamics studies of aqueous silica nanoparticle dispersions: salt effects on the double layer formation.

    PubMed

    de Lara, Lucas S; Rigo, Vagner A; Michelon, Mateus F; Metin, Cigdem O; Nguyen, Quoc P; Miranda, Caetano R

    2015-08-19

    The ion distribution around hydroxylated silica nanoparticles (NP-H) dispersed in brine was investigated by fully atomistic molecular dynamics. The NP-H dispersions in aqueous electrolyte media are simulated in solutions of varying salinity (NaCl, CaCl2, and MgCl2), salt concentration (0.06  ×  10(-3) to 3.00  ×  10(-3) mole fraction [Formula: see text]), and temperature (300 and 350 K) at 1 atm. The NP-H models reproduce the observed experimental concentration of silanol and geminal surface sites, which are responsible for local charge variations on the nanoparticles' surface. Interestingly, under certain salt concentration conditions, the formation of an electrical double layer (DL) around the overall neutral NP-H occurs. The resulting DLs are attenuated with increasing temperature for all evaluated salts. With increasing salt concentration, a sign inversion of the effective charge at the first ion layer is observed, which modifies the electrostatic environment around the nanoparticle. The minimum salt concentration that leads to a DL formation at 300 K is 1.05  ×  10(-3), 0.37  ×  10(-3), and 0.06  ×  10(-3) χs for NaCl, CaCl2, and MgCl2, respectively. The width of the DL decreases sequentially in ionic strength from NaCl to CaCl2 to MgCl2, which is similar to that found for highly charged surfaces. These results are in line with our previous experimental data for negative charged NP-H. All together, these observations suggest an interplay mechanism between the formation and narrowing of electric double layers on the stability of NP dispersions in both neutral and negatively charged NP-H. PMID:26194994

  12. Lithofacies and palynostratigraphy of some Cretaceous and Paleocene rocks, Surghar and Salt Range coal fields, northern Pakistan

    USGS Publications Warehouse

    Warwick, Peter D.; Javed, Shahid; Mashhadi, S. Tahir A.; Shakoor, Tariq; Khan, Asrar M.; Khan, A. Latif

    1995-01-01

    The stratigraphic relation between the Cretaceous generally non-coal-bearing Lumshiwal Formation (64 to 150 m thick) and the Paleocene coal-bearing Hangu Formation (5 to 50 m thick) in the Surghar Range of north-central Pakistan is complex. Both formations contain remarkably similar lithofacies: one or two types of sandstone lithofacies; a combined lithofacies of mudstone, claystone, carbonaceous shale, and coal beds; and a rare carbonate lithofacies. An analysis of pollen data from rock samples collected from various stratigraphic positions indicates that the formations are separated by a disconformity and that the age of the Lumshiwal Formation is Early Cretaceous and the age of the Hangu is Paleocene. Previous workers had suggested that the age of the Lumshiwal is Late Cretaceous. An analysis of sedimentologic, stratigraphic, and paleontologic data indicates that both the Lumshiwal and Hangu Formations probably were deposited in shallow-marine and deltaic environments. The rocks of the Lumshiwal become more terrestrial in origin upward, whereas the rocks of the Hangu become more marine in origin upward. The contact between the two formations is associated with a laterally discontinuous lateritic paleosol (assigned to the Hangu Formation) that is commonly overlain by the economically important Makarwal coal bed. This coal bed averages 1.2 m in thickness. No other coal beds in the Surghar Range are as thick or as laterally continuous as the Makarwal coal bed. Analytical data from the Makarwal and one other Hangu coal bed indicate that Surghar Range coal beds range from high-volatile B to high-volatile C bituminous in apparent rank. Averaged, as-received results of proximate and ultimate analyses of coal samples are (1) moisture content, 5.4 percent; (2) ash yield, 12.5 percent; (3) total sulfur content, 5 percent; and (4) calorific value, 11034 Btu/lb (British thermal units per pound). Minor- and trace-element analyses indicate that these coals contain relatively

  13. Shock metamorphism of Bosumtwi impact crater rocks, shock attenuation, and uplift formation.

    PubMed

    Ferrière, Ludovic; Koeberl, Christian; Ivanov, Boris A; Reimold, Wolf Uwe

    2008-12-12

    Shock wave attenuation rate and formation of central uplifts are not precisely constrained for moderately sized complex impact structures. The distribution of shock metamorphism in drilled basement rocks from the 10.5-kilometer-diameter Bosumtwi crater, and results of numerical modeling of inelastic rock deformation and modification processes during uplift, constrained with petrographic data, allowed reconstruction of the pre-impact position of the drilled rocks and revealed a shock attenuation by approximately 5 gigapascals in the uppermost 200 meters of the central uplift. The proportion of shocked quartz grains and the average number of planar deformation feature sets per grain provide a sensitive indication of minor changes in shock pressure. The results further imply that for moderately sized craters the rise of the central uplift is dominated by brittle failure. PMID:19074347

  14. Pitted rock surfaces on Mars: A mechanism of formation by transient melting of snow and ice

    NASA Astrophysics Data System (ADS)

    Head, James W.; Kreslavsky, Mikhail A.; Marchant, David R.

    2011-09-01

    Pits in rocks on the surface of Mars have been observed at several locations. Similar pits are observed in rocks in the Mars-like hyperarid, hypothermal stable upland zone of the Antarctic Dry Valleys; these form by very localized chemical weathering due to transient melting of small amounts of snow on dark dolerite boulders preferentially heated above the melting point of water by sunlight. We examine the conditions under which a similar process might explain the pitted rocks seen on the surface of Mars (rock surface temperatures above the melting point; atmospheric pressure exceeding the triple point pressure of H2O; an available source of solid water to melt). We find that on Mars today each of these conditions is met locally and regionally, but that they do not occur together in such a way as to meet the stringent requirements for this process to operate. In the geological past, however, conditions favoring this process are highly likely to have been met. For example, increases in atmospheric water vapor content (due, for example, to the loss of the south perennial polar CO2 cap) could favor the deposition of snow, which if collected on rocks heated to above the melting temperature during favorable conditions (e.g., perihelion), could cause melting and the type of locally enhanced chemical weathering that can cause pits. Even when these conditions are met, however, the variation in heating of different rock facets under Martian conditions means that different parts of the rock may weather at different times, consistent with the very low weathering rates observed on Mars. Furthermore, as is the case in the stable upland zone of the Antarctic Dry Valleys, pit formation by transient melting of small amounts of snow readily occurs in the absence of subsurface active layer cryoturbation.

  15. Mechanics of graben formation in crustal rocks - A finite element analysis

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Williams, C. A., Jr.

    1989-01-01

    The mechanics of the initial stages of graben formation are examined, showing that the configuration of a graben (a pair of antithetically dipping normal faults) is the most energetically favorable fault configuration in elastic-brittle rocks subjected to pure extension. The stress field in the vicinity of a single initial normal fault is computed with a two-dimensional FEM. It is concluded that the major factor controlling graben width is the depth of the initial fault.

  16. Petroleum source rock evaluation of the Sebahat and Ganduman Formations, Dent Peninsula, Eastern Sabah, Malaysia

    NASA Astrophysics Data System (ADS)

    Mustapha, Khairul Azlan; Abdullah, Wan Hasiah

    2013-10-01

    The Sebahat (Middle Miocene to Early Pliocene) and Ganduman (Early Pliocene to Late Pliocene) Formations comprise part of the Dent Group. The onshore Sebahat and Ganduman Formations form part of the sedimentary sequence within the Sandakan sub-basin which continues offshore in the southern portion of the Sulu Sea off Eastern Sabah. The Ganduman Formation lies conformably on the Sebahat Formation. The shaly Sebahat Formation represents a distal holomarine facies while the sandy Ganduman Formation represents the proximal unit of a fluvial-deltaic system. Based on organic geochemical and petrological analyses, both formations posses very variable TOC content in the range of 0.7-48 wt% for Sebahat Formation and 1-57 wt% for Ganduman Formation. Both formations are dominated by Type III kerogen, and are thus considered to be gas-prone based on HI vs. Tmax plots. Although the HI-Tmax diagram indicates a Type III kerogen, petrographic observations indicate a significant amount of oil-prone liptinite macerals. Petrographically, it was observed that significant amounts (1-17% by volume) of liptinite macerals are present in the Ganduman Formation with lesser amounts in the Sebahat Formation. Both formations are thermally immature with vitrinite reflectance values in the range of 0.20-0.35%Ro for Ganduman Formation and 0.25-0.44%Ro for Sebahat Formation. Although these onshore sediments are thermally immature for petroleum generation, the stratigraphic equivalent of these sediments offshore are known to have been buried to deeper depth and could therefore act as potential source rocks for gas with minor amounts of oil.

  17. Resistance of halobacterial isolates from Permian rock salt to physico-chemical extremes, including heat and a simulated Martian atmosphere.

    NASA Astrophysics Data System (ADS)

    Leuko, S.; Weidler, G.; Radax, C.; Stan-Lotter, H.

    2003-04-01

    Extremely halophilic archaebacteria (halobacteria) are found today in hypersaline surface waters, such as the brines in solar salterns, or the Dead Sea. However, from Alpine rock salt of Permo-Triassic age several species of halobacteria were isolated during the last years (1, 2). Halobacteria are not known to produce spores or dormant forms; thus it remains enigmatic how they survived in the salt sediments. Extraterrestrial halite has been detected in meteorites from Mars and from the asteroids; in addition, the Jovian moon Europa is thought to contain a salty ocean. Therefore halobacteria would be useful model organisms when considering the search for extraterrestrial life. We are developing experimental protocols to evaluate the effects of physico-chemical stress factors on halobacteria, in particular present-day Martian conditions. But the effect of higher temperatures is also of interest, since Mars may have been warmer in the past, and the Alpine salt sediments are known to have experienced local temperature peaks. Cells of Halococcus dombrowskii (2) and, for comparison, of Halobacterium sp. NRC-1 were grown in complex medium, containing up to 4 M NaCl (2). Aliquots of cultures were kept at minus 70oC for several days, or freeze-dried in a lyophilizer, or incubated at temperatures of 50 to 80oC for 24 hours, respectively. In addition, exposure experiments of halobacterial cells in a liquid nitrogen cooled Martian simulation chamber were begun. Survival of cells was evaluated by determining colony-forming units and by examination of cellular morphology by fluorescence microscopy, following staining with the LIVE-DEAD kit. Results indicated that the LIVE-DEAD kit can be successfully used in the presence of 4 M NaCl, although it was developed for tests at low ionic strength. Data will be presented which show that Hc. dombrowskii survived deep freezing, temperatures of up to 80 oC and Martian atmospheric conditions generally better than Halobacterium sp. NRC-1

  18. Clast formation in cinder cone vents: Negro Rock, Malheur County, Oregon

    SciTech Connect

    Atkinson, M.G. . Geology Dept.); Pasek, T.A. ); Cummings, M.L. . Geology Dept.)

    1993-04-01

    Negro Rock is an andesitic vent complex within the middle to late Miocene Grassy Mountain Formation. Negro Rock complex includes two central vents that intrude palagonitic tephra formed during an earlier episode of hydrovolcanic-dominated volcanism. In the southwestern vent, Negro Rock, progressive fragmentation from a chilled wall to open textured scoria is preserved. Chilled, vesicle-free andesite against contact metamorphosed palagonitic tephra forms the outer wall of the vent. Inward, strongly vertically stretched vesicles occur in crudely flow banded andesite. The stretch textures give way to isolated patches of small vesicles in a non-vesiculated, non-stretched matrix. The size and abundance of vesicles patches increases inward. The non-vesiculated portion steadily decreases to a dense rim around vesiculated incipient clasts. As clast forms become more prominent the color changes from dark gray to purple. Liberated scoria clasts are red and occur with an assortment of blocks and fusiform bombs within the vent. Clast formation is due to magmatic degassing within the base of the cinder cone. The northeastern, higher vent shows incipient clast formation near the summit.

  19. Clarifying the role of rigidity contrasts and rock interface strength in sill formation processes

    NASA Astrophysics Data System (ADS)

    Kavanagh, J.; Pavier, M.; Menand, T.; Sparks, R. S. J.

    2012-04-01

    Field observations, numerical and analogue models suggest rigidity contrasts may play an important role in sill formation processes. We present results from analogue experiments and rock strength tests which explore the additional role that rock interface strength could have on the geometry and propagation dynamics of magmatic intrusions. Dyed water (a magma analogue) was injected into layers of solidified gelatine (a crustal analogue) to form experimental dykes and sills. The intrusions were pressure-driven and injected under initially hydrostatic conditions. From 4 to ~15 °C gelatine deforms elastically, and under these conditions the tensile strength of the gelatine (Youngs Modulus) evolves following a power-law relationship that plateaus with time. Varying the concentration of the gelatine allows layer strength contrasts as low as 1% to be created. Our results show that in a two-layered system the upper layer needs to be at least 10% more rigid than the lower layer to cause dyke arrest. An experimental sill then forms if the interface between the layers is weak; otherwise a lateral dyke forms. To test rock interface strength variation in nature we used a 1 kN servo hydraulic test machine to test 5 mm thick cuboidal specimens of sandstone-siltstone rock core where the interface between the strata is preserved. By measuring the load required to grow a starter crack running along the lithological contact between the layers we can calculate its fracture toughness (a measure of the material resistance to the growth of a crack). The results show the rock interfaces have intermediate fracture toughness to their parent units. These results bring into question the relative roles of magma viscosity versus rock fracturing in controlling the nature and propagation dynamics of magmatic intrusions.

  20. Depositional environments of Permian Phosphoria Formation and related rocks, Leach Mountains, northeast Nevada

    SciTech Connect

    Martindale, S.G. )

    1991-02-01

    In the Leach Mountains, northeastern Nevada, the Phosphoria Formation is represented by phosphatic rocks of the late Leonardian Meade Peak Phosphatic Shale Tongue. The Meade Peak is overlain by dolomitic siltstones and chert, including black bedded chert, of the upper Leonardian( ) to lower Guadalupian Murdock Mountain Formation. The black bedded chert is related to the Rex Chert Member of the Phosphoria Formation. There is little consensus regarding depositional environments of the Meade Peak. Also, little work has been presented on the origin of the black bedded cherts such as in the Murdock Mountain and Rex Chert. Locally, a shallow subtidal to perhaps partly intertidal depositional model for the Meade Peak is based upon characteristics of reworked phosphatic clasts, a crowded and mixed shallow-water fauna, oolite beds, and stratigraphic position between shallow subtidal to supratidal rocks. Supratidal deposition of dolomitic siltstones and units of black bedded chert in the Murdock Mountain is based largely on abundant cauliflower-shaped blebs of chalcedony with shapes resembling modern anhydrite nodules. Also, zebraic chalcedony in the black bedded chert is interpreted as a replacement product of evaporite deposits. The setting in this southwestern part of the depositional basin of the Phosphoria Formation, in the late Leonardian, during the deposition of the Meade Peak, is interpreted as a network of shallow to very shallow marine basins and intervening, perhaps periodically merged shoals. Subsequently, during the late Leonardian( ) to early Guadalupian, there was a marine regression and the supratidal environment of the Murdock Mountain Formation was established.

  1. First-principles study of rock-salt AgCl xBr 1-x alloys

    NASA Astrophysics Data System (ADS)

    Amrani, B.; El Haj Hassan, F.; Zoaeter, M.

    2007-06-01

    We present first-principles calculations of the structural, electronic and thermodynamic properties of rock-salt AgCl xBr 1-x alloys by application of the full potential linearized augmented plane wave (FP-LAPW) method. We use both Perdew-Burke-Ernzerhof and Engel-Vosko generalized gradient approximations of the exchange-correlation energy that are based on the optimization of total energy and corresponding potential, respectively. The effect of composition on lattice constants, bulk modulus, cohesive energy, bond ionicity, band gap and effective mass was investigated. These parameters were found to depend nonlinearly on alloy composition x, except the lattice parameter, which follows Vegard's law. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers; we have concluded that the band gap energy bowing was mainly caused by the chemical charge-transfer effect, while the volume deformation and the structural relaxation contribute to the gap bowing parameter at smaller magnitude. On the other hand, the thermodynamic stability of AgCl xBr 1-x was investigated by calculating the excess enthalpy of mixing Δ Hm as well as the phase diagram.

  2. Electrochemical characteristics of Li 2- xVTiO 4 rock salt phase in Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Dominko, R.; Garrido, C. Vidal-Abraca; Bele, M.; Kuezma, M.; Arcon, I.; Gaberscek, M.

    Li 2- xVTiO 4/C sample with a disordered rock salt structure was successfully prepared by annealing at a temperature of 850 °C. The electrochemical oxidation in the first cycle occurs at voltages above 4 V vs. metallic lithium, while the shapes of the electrochemical curves in consequent reduction-oxidation processes show a monotonous change of the potential between the selected cut-off voltages. A linear combination fit of individual XANES spectra was used for the determination of the oxidation states of as prepared sample and intermediate states during oxidation and reduction. In the as-prepared sample, vanadium was found to be in the average oxidation state of V 3.5+ and was additionally oxidized to V 3.8+ by the electrochemical charging. During the discharge process, the vanadium oxidation state was reduced to V 3.0+. In situ X-ray diffraction patterns and EXAFS analysis suggest good structural stability during oxidation and reduction, which is also reflected in the cycling stability if batteries were cycled in the voltage window between 2.0 V and 4.4 V. Extension of the lower cut-off voltage to 1.0 V doubles the capacity retention with the improved capacity stability if compared with several high capacity vanadium based materials.

  3. Hydrous mineral dehydration around heat-generating nuclear waste in bedded salt formations.

    PubMed

    Jordan, Amy B; Boukhalfa, Hakim; Caporuscio, Florie A; Robinson, Bruce A; Stauffer, Philip H

    2015-06-01

    Heat-generating nuclear waste disposal in bedded salt during the first two years after waste emplacement is explored using numerical simulations tied to experiments of hydrous mineral dehydration. Heating impure salt samples to temperatures of 265 °C can release over 20% by mass of hydrous minerals as water. Three steps in a series of dehydration reactions are measured (65, 110, and 265 °C), and water loss associated with each step is averaged from experimental data into a water source model. Simulations using this dehydration model are used to predict temperature, moisture, and porosity after heating by 750-W waste canisters, assuming hydrous mineral mass fractions from 0 to 10%. The formation of a three-phase heat pipe (with counter-circulation of vapor and brine) occurs as water vapor is driven away from the heat source, condenses, and flows back toward the heat source, leading to changes in porosity, permeability, temperature, saturation, and thermal conductivity of the backfill salt surrounding the waste canisters. Heat pipe formation depends on temperature, moisture availability, and mobility. In certain cases, dehydration of hydrous minerals provides sufficient extra moisture to push the system into a sustained heat pipe, where simulations neglecting this process do not. PMID:25965632

  4. Direct Observation of Formation Behavior of Metal Emulsion in Sn/Salt System

    NASA Astrophysics Data System (ADS)

    Yoshida, Hironori; Liu, Jiang; Kim, Sun-Joong; Gao, Xu; Ueda, Shigeru; Maruoka, Nobuhiro; Ono, Shinpei; Kitamura, Shin-ya

    2016-05-01

    Using two systems with different interfacial tensions, the behavior of metal emulsions during bottom blowing was observed directly with a high-speed camera. The interfacial tension between molten salt (KCl-LiCl-NaCl) and molten Sn was measured by a pendant drop method, and it decreased to about 100 mN/m when the Te content in Sn increased from 0 to 0.5 pct. In both systems, two types of metal emulsion behaviors were observed. In Mode A, fine metal droplets were formed after the metal film ruptured at the interface. In Mode B, the formation of coarse droplets was observed after the disintegration of the column generated by the rising bubble, and the number of droplets increased with the gas flow rate compared to that in Mode A. The generating frequency of each mode revealed that Mode B became dominant with increasing gas flow rate. In the pure Sn/salt system, the numbers of droplets of Mode B showed a local maximum at high gas flow rates, but the numbers of droplets in Sn-0.5 pctTe/salt increased continuously even in the same flow range. Regarding the size distribution, the percentage of coarse metal droplets in the Sn-0.5 pctTe alloy/salt was larger than that in the pure Sn/salt. Furthermore, the effect of interfacial tension on the variation in surface area and volume of the droplets showed a similar tendency for the column height. Therefore, a decrement of the interfacial tension led to an increment of the column height when Mode B occurred and finally resulted in a higher interfacial area.

  5. Direct Observation of Formation Behavior of Metal Emulsion in Sn/Salt System

    NASA Astrophysics Data System (ADS)

    Yoshida, Hironori; Liu, Jiang; Kim, Sun-Joong; Gao, Xu; Ueda, Shigeru; Maruoka, Nobuhiro; Ono, Shinpei; Kitamura, Shin-ya

    2016-08-01

    Using two systems with different interfacial tensions, the behavior of metal emulsions during bottom blowing was observed directly with a high-speed camera. The interfacial tension between molten salt (KCl-LiCl-NaCl) and molten Sn was measured by a pendant drop method, and it decreased to about 100 mN/m when the Te content in Sn increased from 0 to 0.5 pct. In both systems, two types of metal emulsion behaviors were observed. In Mode A, fine metal droplets were formed after the metal film ruptured at the interface. In Mode B, the formation of coarse droplets was observed after the disintegration of the column generated by the rising bubble, and the number of droplets increased with the gas flow rate compared to that in Mode A. The generating frequency of each mode revealed that Mode B became dominant with increasing gas flow rate. In the pure Sn/salt system, the numbers of droplets of Mode B showed a local maximum at high gas flow rates, but the numbers of droplets in Sn-0.5 pctTe/salt increased continuously even in the same flow range. Regarding the size distribution, the percentage of coarse metal droplets in the Sn-0.5 pctTe alloy/salt was larger than that in the pure Sn/salt. Furthermore, the effect of interfacial tension on the variation in surface area and volume of the droplets showed a similar tendency for the column height. Therefore, a decrement of the interfacial tension led to an increment of the column height when Mode B occurred and finally resulted in a higher interfacial area.

  6. Petrophysical properties of carbonate rocks: example from the cretaceous Jandaira Formation, Potiguar basin - Brazil

    NASA Astrophysics Data System (ADS)

    Nogueira, Francisco; Soares, José; Bezerra, Francisco; Cavalcanti, Bruno; Cazarin, Caroline

    2015-04-01

    Carbonate sediments are prone to rapid and pervasive diagenetic alterations that change the mineralogy and pore structure within carbonate units. In particular, cementation and dissolution processes continuously modify the pore structure to create or destroy porosity. In extreme cases these modifications can completely change the mineralogy from calcite to dolomite, in the properties of rock for soil (Caliche), or reverse the pore distribution whereby original grains are dissolved to produce pores as the original pore space is filled with cement to form the rock. These processes are common in fractured carbonate units. All these modifications alter the elastic properties of the rock and, therefore, the sonic velocity. This study presents the result of relationship among diagenesis, porosity, grain density, and sonic velocity, in limestones, dolomites and caliche samples from the Jandaíra Formation, Potiguar basin, Brasil. This stratigraphic unit have been subjected to fracturing since the late Cretaceous. The rock and soil samples were collected in outcrops, prepared as plugs, and analyzed at ambient temperature. The porosity and grain density analysis were performed under ambient pressure, while elastic properties analyses were conducted with samples under confining pressure between 5 and 40 MPa. The result is a wide range of sonic velocity in carbonates, in which compressional-wave velocity (VP) ranges from 3507 to 6119 m/s and shear-wave velocity (VS) range from 2114 to 3451 m/s. The ratio VS1/VS2 indicate a level of anisotropy equal to 2%, without any clear relationship with porosity. The elastics properties are affected by rock alteration process or by modification of mineral composition, due to the presence of clay minerals and organic matter, The porosity and grain density values range from 3.2 to 21.5%, and 2.7 to 2.8 (g/cm3), respectively. The grain density analysis in the carbonate rocks indicate the existence of two groups: the first group of calcareous

  7. Quarries of Culture: An Ethnohistorical and Environmental Account of Sacred Sites and Rock Formations in Southern California's Mission Indian Country

    ERIC Educational Resources Information Center

    Karr, Steven M.

    2005-01-01

    Sacred sites and Rock Formations throughout Southern California's India Country are described by Indians as ancestral markers, origin and place-name locales, areas of deity habitation, and power sources. Early ethnographers were keen to record the traditional stories and meanings related to them by their Native collaborators. Rock formations…

  8. Potassium ions are more effective than sodium ions in salt induced peptide formation.

    PubMed

    Dubina, Michael V; Vyazmin, Sergey Yu; Boitsov, Vitali M; Nikolaev, Eugene N; Popov, Igor A; Kononikhin, Alexey S; Eliseev, Igor E; Natochin, Yuri V

    2013-04-01

    Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K(+) is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na(+), which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K(+) as the driving force, not Na(+), as commonly believed. PMID:23536046

  9. Potassium Ions are More Effective than Sodium Ions in Salt Induced Peptide Formation

    NASA Astrophysics Data System (ADS)

    Dubina, Michael V.; Vyazmin, Sergey Yu.; Boitsov, Vitali M.; Nikolaev, Eugene N.; Popov, Igor A.; Kononikhin, Alexey S.; Eliseev, Igor E.; Natochin, Yuri V.

    2013-04-01

    Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K+ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na+, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K+ as the driving force, not Na+, as commonly believed.

  10. Formation of drug-bearing vesicles in mixed colloids of bile salts and phosphatidylcholine

    SciTech Connect

    Hjelm, R.P.; Mang, J.; Hofmann, A.F.; Schteingart, C.; Alkan-Onyuksel, H.; Ayd, S.

    1997-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors used small-angle neutron scattering to study drug interactions with mixed colloids of bile salt and phosphatidylcholine. Because the mixed colloids form liposomes spontaneously, this system is a model for drug-bile interactions that are important in understanding the efficacy of oral drug formulations and in advanced applications for liposome drug delivery systems. The authors studied particle formation in incorporation of enzymatic products formed in the gut and the effects of cholesteric drugs and taxol on vesicle formation. The studies show that particle morphology is not affected by inclusion of most cholesteric drugs and taxol, and is not affected by incorporation of the products of enzymatic action. The findings suggest that particle form is important for the physiological function of bile and they are beginning to show which drugs affect liposome formation.

  11. Phosphate rock formation and marine phosphorus geochemistry: the deep time perspective.

    PubMed

    Filippelli, Gabriel M

    2011-08-01

    The role that phosphorite formation, the ultimate source rock for fertilizer phosphate reserves, plays in the marine phosphorus (P) cycle has long been debated. A shift has occurred from early models that evoked strikingly different oceanic P cycling during times of widespread phosphorite deposition to current thinking that phosphorite deposits may be lucky survivors of a series of inter-related tectonic, geochemical, sedimentological, and oceanic conditions. This paradigm shift has been facilitated by an awareness of the widespread nature of phosphogenesis-the formation of authigenic P-bearing minerals in marine sediments that contributes to phosphorite formation. This process occurs not just in continental margin sediments, but in deep sea oozes as well, and helps to clarify the driving forces behind phosphorite formation and links to marine P geochemistry. Two processes come into play to make phosphorite deposits: chemical dynamism and physical dynamism. Chemical dynamism involves the diagenetic release and subsequent concentration of P-bearing minerals particularly in horizons, controlled by a number of sedimentological and biogeochemical factors. Physical dynamism involves the reworking and sedimentary capping of P-rich sediments, which can either concentrate the relatively heavy and insoluble disseminated P-bearing minerals or provide an episodic change in sedimentology to concentrate chemically mobilized P. Both processes can result from along-margin current dynamics and/or sea level variations. Interestingly, net P accumulation rates are highest (i.e., the P removal pump is most efficient) when phosphorites are not forming. Both physical and chemical pathways involve processes not dominant in deep sea environments and in fact not often coincide in space and time even on continental margins, contributing to the rarity of high-quality phosphorite deposits and the limitation of phosphate rock reserves. This limitation is becoming critical, as the human demand

  12. Synthesis of rock-salt type lithium borohydride and its peculiar Li+ ion conduction properties

    NASA Astrophysics Data System (ADS)

    Miyazaki, R.; Maekawa, H.; Takamura, H.

    2014-05-01

    The high energy density and excellent cycle performance of lithium ion batteries makes them superior to all other secondary batteries and explains why they are widely used in portable devices. However, because organic liquid electrolytes have a higher operating voltage than aqueous solution, they are used in lithium ion batteries. This comes with the risk of fire due to their flammability. Solid electrolytes are being investigated to find an alternative to organic liquid. However, the nature of the solid-solid point contact at the interface between the electrolyte and electrode or between the electrolyte grains is such that high power density has proven difficult to attain. We develop a new method for the fabrication of a solid electrolyte using LiBH4, known for its super Li+ ion conduction without any grain boundary contribution. The modifications to the conduction pathway achieved by stabilizing the high pressure form of this material provided a new structure with some LiBH4, more suitable to the high rate condition. We synthesized the H.P. form of LiBH4 under ambient pressure by doping LiBH4 with the KI lattice by sintering. The formation of a KI - LiBH4 solid solution was confirmed both macroscopically and microscopically. The obtained sample was shown to be a pure Li+ conductor despite its small Li+ content. This conduction mechanism, where the light doping cation played a major role in ion conduction, was termed the "Parasitic Conduction Mechanism." This mechanism made it possible to synthesize a new ion conductor and is expected to have enormous potential in the search for new battery materials.

  13. Dual effectiveness of lithium salt in controlling both delayed ettringite formation and ASR in concretes

    SciTech Connect

    Ekolu, S.O. . E-mail: stephen.ekolu@wits.ac.za; Thomas, M.D.A.; Hooton, R.D.

    2007-06-15

    The influence of lithium nitrate on expansions due to delayed ettringite formation (DEF) and alkali-silica reaction (ASR) has been investigated. Effects of the lithium salt were examined in heat-cured mortars and concretes containing one or both damage mechanisms. The mortars and concretes made using reactive and/or non-reactive aggregates were subjected to heat treatment consisting of a hydration delay period of 4 h at 23 deg. C followed by steam-curing at 95 deg. C and then stored in limewater. Results showed that the lithium salt admixture was able to reduce the occurrence of deleterious expansion due to delayed ettringite formation in addition to controlling alkali-silica reaction in cementitious systems containing one or both mechanisms. In concretes made using non-reactive limestone aggregates, incorporation of lithium nitrate in a proportion of 0.74 M ratio of Li to (Na + K) was found to control delayed ettringite formation during the one-year period of this study. By analyzing the leaching properties of lithium and other alkalis from mortars during storage, it was found that a substantial amount of lithium was retained in the cementitious system in a slightly soluble form, and is expected to be responsible for reducing DEF.

  14. The impact of mastication, salivation and food bolus formation on salt release during bread consumption.

    PubMed

    Tournier, Carole; Grass, Manon; Septier, Chantal; Bertrand, Dominique; Salles, Christian

    2014-11-01

    Health authorities recommend higher fibre and lower salt content in bread products. However, these basic ingredients of bread composition are multifunctional, and important changes in their content influence the texture, flavour and acceptability of the product. This study was designed to investigate the link between oral processing, bolus formation and sodium release during the consumption of four different breads that varied in composition and structure. Chewing behaviour was determined by surface electromyography, and salivation was quantified from the water content of the boluses collected. The kinetics of bread degradation during food bolus formation was characterised by measuring the bolus heterogeneity by texture image analysis, and sodium release into the saliva was quantified. Mastication and salivation varied between products and between subjects, thus highlighting different bolus formation strategies. In vivo salt release was mainly explained by mastication parameters. The initial slope of sodium release increased when the chewing muscles' activity increased, and the maximum sodium concentration was reached later when more masticatory cycles were required to reach the swallowing point. PMID:25225783

  15. Oleate salt formation and mesomorphic behavior in the propranolol/oleic acid binary system.

    PubMed

    Crowley, K J; Forbes, R T; York, P; Nyqvist, H; Camber, O

    1999-06-01

    Thermal analysis of propranolol/oleic acid mixtures prepared by solvent evaporation enabled construction of the binary system phase diagram. This allowed both physical and chemical interactions to be identified, including complex formation at the equimolar composition. An incongruent melting complex with a characteristic reaction point was identified in excess oleic acid compositions, a common property of fatty acid/fatty acid salt binary systems. The equimolar complex was confirmed to be propranolol oleate using infrared spectroscopy. Wide-angle X-ray powder diffractometry demonstrated that propranolol oleate possessed long-range positional order ( approximately 25 A d spacing) accompanied by a degree of disorder over shorter d spacings. Such a pattern suggested mesophase formation, explaining the unctuous nature of propranolol oleate at room temperature. Accurate measurement of the long-range d spacing was achieved using small-angle X-ray scattering, permitting differentiation of the three different phases identified (phase I: 25.4 A, phase II: 24.6 A, phase III: 25.4-25.5 A). The implications of drug fatty acid salt formation and also mesomorphism in pharmaceutical systems are discussed. PMID:10350493

  16. ROCK activity regulates functional tight junction assembly during blastocyst formation in porcine parthenogenetic embryos

    PubMed Central

    Kwon, Jeongwoo

    2016-01-01

    The Rho-associated coiled-coil-containing protein serine/threonine kinases 1 and 2 (ROCK1 and ROCK2) are Rho subfamily GTPase downstream effectors that regulate cell migration, intercellular adhesion, cell polarity, and cell proliferation by stimulating actin cytoskeleton reorganization. Inhibition of ROCK proteins affects specification of the trophectoderm (TE) and inner cell mass (ICM) lineages, compaction, and blastocyst cavitation. However, the molecules involved in blastocyst formation are not known. Here, we examined developmental competence and levels of adherens/tight junction (AJ/TJ) constituent proteins, such as CXADR, OCLN, TJP1, and CDH1, as well as expression of their respective mRNAs, after treating porcine parthenogenetic four-cell embryos with Y-27632, a specific inhibitor of ROCK, at concentrations of 0, 10, 20, 100 µM for 24 h. Following this treatment, the blastocyst development rates were 39.1, 20.7, 10.0, and 0% respectively. In embryos treated with 20 µM treatment, expression levels of CXADR, OCLN, TJP1, and CDH1 mRNA and protein molecules were significantly reduced (P < 0.05). FITC-dextran uptake assay revealed that the treatment caused an increase in TE TJ permeability. Interestingly, the majority of the four-cell and morula embryos treated with 20 µM Y-27643 for 24 h showed defective compaction and cavitation. Taken together, our results indicate that ROCK activity may differentially affect assembly of AJ/TJs as well as regulate expression of genes encoding junctional proteins. PMID:27077008

  17. Thermal formation of methylammonium methylcarbamate in interstellar ice analogs: a glycine salt precursor under VUV irradiation

    NASA Astrophysics Data System (ADS)

    Duvernay, Fabrice; Borget, Fabien; Bossa, Jean-Baptiste; Theule, Patrice; Dhendecourt, Louis; Chiavassa, Thierry

    Dust grains in the interstellar medium (ISM) play an important role in dense molecular clouds chemistry of providing a surface (catalyst) upon which atoms and molecules can freeze out, forming icy mantles. Dense molecular clouds are characterized by low temperature (10 -50 K) and represent the birth sites of stars. After a gravitationnal breakdown, a part of the dense molecular cloud collapses toward the formation of star and subsequently a protoplanetary disk from which planets, asteroids and comets will appear. During this evolution, interstellar or-ganic material inside ices undergoes different range of chemical alterations (thermal cycling process, ultraviolet photons, electron scattering and cosmic rays irradiation) hence increasing the molecular complexity before their incorporation inside precometary ices. To date, it is supposed that comets could have delivered to the early Earth the organic materials essential to a prebiotic chemistry, one of the prerequisites toward the origin of living systems. The for-mation of prebiotical molecules such as the simplest amino acids (glycine) is proposed in this current study mainly based on laboratory experiments simulating the chemistry occuring on ices within protostellar environments. Infrared spectroscopy and mass spectroscopy are used to monitor the thermal formation of glycine isomer form: the methylammonium methylcarbamate [CH3NH3+][CH3NHCOO-] in interstellar ice analogs made up of two astrophysical relevant molecules: carbon dioxide (CO2) and methylamine (CH3NH2). Using infrared spectroscopy, we study the photochemical behaviour of a pure sample of methylammonium methylcarbamate under vacuum ultraviolet (VUV) field. We show that a glycine isomer salt could readily enter into the composition of ices in colder region of protostellar environments. Upon ultraviolet irra-diation, this latter can undergo an isomerization process induced by photons yielding a glycine salt: the methylammonium glycinate [CH3NH3+][NH2CH2

  18. Chapter 39 The Edwardsburg Formation and related rocks, Windermere Supergroup, central Idaho, USA

    USGS Publications Warehouse

    Lund, Karen; Evans, Karl V.; Alienikoff, John N.

    2011-01-01

    In central Idaho, Neoproterozoic stratified rocks are engulfed by the Late Cretaceous Idaho batholith and by Eocene volcanic and plutonic rocks of the Challis event. Studied sections in the Gospel Peaks and Big Creek areas of west-central Idaho are in roof pendants of the Idaho batholith. A drill core section studied from near Challis, east-central Idaho, lies beneath the Challis Volcanic Group and is not exposed at the surface. Metamorphic and deformational overprinting, as well as widespread dismembering by the younger igneous rocks, conceals many primary details. Despite this, these rocks provide important links for regional correlations and have produced critical geochronological data for two Neoproterozoic glacial periods in the North American Cordillera. At the base of the section, the more than 700-m-thick Edwardsburg Formation (Fm.) contains interlayered diamictite and volcanic rocks. There are two diamictite-bearing members in the Edwardsburg Fm. that are closely related in time. Each of the diamictites is associated with intermediate composition tuff or flow rocks and the diamictites are separated by mafic volcanic rocks. SHRIMP U–Pb dating indicates that the lower diamictite is about 685±7 Ma, whereas the upper diamictite is 684±4 Ma. The diamictite units are part of a cycle of rocks from coarse clastic, to fine clastic, to carbonate rocks that, by correlation to better preserved sections, are thought to record an older Cryogenian glacial to interglacial period in the northern US Cordillera. The more than 75-m-thick diamictite of Daugherty Gulch is dated at 664±6 Ma. This unit is preserved only in drill core and the palaeoenvironmental interpretation and local stratigraphic relations are non-unique. Thus, the date for this diamictite may provide a date for a newly recognized glaciogenic horizon or may be a minimum age for the diamictite in the Edwardsburg Fm. The c. 1000-m-thick Moores Lake Fm. is an amphibolite facies diamictite in which glacial

  19. Altered tuffaceous rocks of the Green River Formation in the Piceance Creek Basin, Colorado

    USGS Publications Warehouse

    Griggs, Roy Lee

    1968-01-01

    More than 50 ash-fall tuff beds which have altered to analcitized or feldspathized rocks have been found in the upper 500-600 feet of the Parachute Creek Member of the Green River Formation in the Piceance Creek Basin of northwestern Colorado. Similarly altered water-washed tuff occurs as tongues in the uppermost part of this member, and forms most of the lower 400-600 feet of the overlying Evacuation Creek Member of the Green River Formation. 'The altered ash-fall beds of the Parachute Creek Member are all thin and show a characteristic pattern of alteration. Most beds range in thickness from a fraction of an inch to a few inches. One bed reaches a maximum thickness of 5 feet, and, unlike the other beds, is composed of several successive ash falls. The pattern of alteration changes from the outer part to the center of the basin. Most beds in the outer part of the basin contain about 50 to 65 percent analcite,with the interstices between the crystals filled mainly by microlites of feldspar, opal, and quartz, and small amounts of carbonate. At the center of the basin .essentially all the beds -are composed of microlites of feldspar, opal, and quartz, and small amounts of carbonate. The tongues of water-washed tuff in the uppermost part of the Parachute Creek Member and the similar rocks composing the lower 400-600 feet of the Evacuation Creek Mewber are feldspathized rocks composed mainly of microlites of feldspar, opal, and quartz, varying amounts of carbonate, and in some specimens tiny subrounded crystals of analcite. The general trend in alteration of the tuffaceous rocks from analcitization near the margin to feidspathization near the center of the Piceance Creek Basin is believed to have taken place at shallow depth during diagenesis , as indicated by field observations and laboratory work. It is believed that during sedimentation and diagenesis the waters of the central part of the basin were more alkaline and following the breakdown of the original

  20. Paleoclimatology indicators of the Salt Wash member of the Upper Jurassic Morrison Formation near Jensen, Utah

    SciTech Connect

    Medlyn, D.A. . Dept. of Geology); Bilbey, S.A. )

    1993-04-01

    The Upper Jurassic Morrison Formation has yielded one of the richest floras of the so-called transitional conifers'' of the Middle Mesozoic. Recently, a silicified axis of one of these conifers was collected from the Salt Wash member in essentially the same horizon as a previously reported partial Stegosaurus skeleton. In addition, two other axes of conifers were collected in the same immediate vicinity. Paleoecological considerations are extrapolated from the coniferous flora, vertebrate fauna and associated lithologies. Techniques of paleodendrology and relationships of extant/extinct environments are compared. The paleoclimatic conditions of the transitional conifers and associated dinosaurian fossils are postulated.

  1. The process of ghost-rock karstification and its role in the formation of cave systems

    NASA Astrophysics Data System (ADS)

    Dubois, C.; Quinif, Y.; Baele, J.-M.; Barriquand, L.; Bini, A.; Bruxelles, L.; Dandurand, G.; Havron, C.; Kaufmann, O.; Lans, B.; Maire, R.; Martin, J.; Rodet, J.; Rowberry, M. D.; Tognini, P.; Vergari, A.

    2014-04-01

    This paper presents an extensive review of the process of ghost-rock karstification and highlights its role in the formation of cave systems. The process integrates chemical weathering and mechanical erosion and extends a number of existing theories pertaining to continental landscape development. It is a two stage process that differs in many respects from the traditional single-stage process of karstification by total removal. The first stage is characterised by chemical dissolution and removal of the soluble species. It requires low hydrodynamic energy and creates a ghost-rock feature filled with residual alterite. The second stage is characterised by mechanical erosion of the undissolved particles. It requires high hydrodynamic energy and it is only then that open galleries are created. The transition from the first stage to the second is driven by the amount of energy within the thermodynamic system. The process is illustrated by detailed field observations and the results of the laboratory analyses of samples taken from the karstotype area around Soignies in southern Belgium. Thereafter, a series of case studies provide a synthesis of field observations and laboratory analyses from across western Europe. These studies come from geologically distinct parts of Belgium, France, Italy, and the United Kingdom. The process of ghost-rock karstification challenges a number of axioms associated with the process of karstification by total removal. On the basis of the evidence presented it is argued that it is no longer acceptable to use karst morphologies as a basis with which to infer specific karstogenetic processes and it is no longer necessary for a karst system to relate to base level as ghost-rock karstification proceeds along transmissive pathways in the rock. There is also some evidence to suggest that ghost-rock karstification may be superseded by karstification by total removal, and vice versa, according to the amount of energy within the thermodynamic system

  2. Salt efflorescence due to water-rock interaction on the surface of tuff cave in the Yoshimi-Hyakuana Historic Site, central Japan

    NASA Astrophysics Data System (ADS)

    Oguchi, Chiaki T.; Kodama, Shogo; Mohammad, Rajib; Tharanga Udagedara, Dashan

    2016-04-01

    Artificial cave walls in Yoshimi Hyakuana Historic Site have been suffering from salt weathering since 1945 when the caves were made. To consider the processes of weathering and subsequent crystallization of secondary minerals, water-rock experiment using tuff from this area was performed. Rocks, surface altered materials, groundwater and rainwater were collected, and chemical and mineralogical characteristics of those samples were investigated. The XRD and SEM-EDS analyses were carried out for the solid samples and ICP-OES analysis was performed for the solution generated from the experiment, groundwater and rainwater. Gypsum is detected in original tuff, and on grey and whiter coloured altered materials. General chemical changes were observed on this rock. However, it is found that purple and black altered materials were mainly made due to microbiological processes.

  3. Palaeoenvironment and Its Control on the Formation of Miocene Marine Source Rocks in the Qiongdongnan Basin, Northern South China Sea

    PubMed Central

    Li, Wenhao; Zhang, Zhihuan; Wang, Weiming; Lu, Shuangfang; Li, Youchuan; Fu, Ning

    2014-01-01

    The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter. PMID:25401132

  4. Palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin, northern South China Sea.

    PubMed

    Li, Wenhao; Zhang, Zhihuan; Wang, Weiming; Lu, Shuangfang; Li, Youchuan; Fu, Ning

    2014-01-01

    The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter. PMID:25401132

  5. Decrypting the Formation Conditions of the Basement Carbonate-Bearing Rocks at Nili Fossae

    NASA Astrophysics Data System (ADS)

    Brown, A. J.

    2015-12-01

    The Nili Fossae region is the site of a number of proposed Landing Sites for the Mars 2020 Rover. A distinguishing feature of many of these sites is the access to large exposures of carbonate (Ehlmann et al. 2008). Serpentinization has been proposed as a formation mechanism of these carbonates, including carbonated (Brown et al. 2010, Viviano, et al. 2013) and low temperature, near surface serpentinization. The potential for carbonated serpentization at Nili Fossae links the region to Earth analogs in terrestrial greenstone belts such as the Pilbara in Western Australia, where talc-carbonate bearing komatiite cumulate units of the Dresser Formation overlie the siliceous, stromatolite-bearing Strelley Pool Chert unit (Van Kranendonk and Pirajno, 2004). If a similar relationship exists on Mars, investigations of rocks stratigraphically beneath the carbonate-bearing units at Nili Fossae ("the basement rocks") may provide the best chance to examine well preserved organic material from the Noachian. This hypothesis is testable by Mars 2020. In preparation for the the Mars 2020 landing site, we are examining the thermodynamic relationships that favor formation of serpentine and talc-carbonate and different pressures and temperatures in the crust (Barnes 2007). This will allow us to constrain the low grade metamorphism required to replicate the proposed models of serpentinisation and help us understand the regional metamophic gradient that is critical to furthering our knowledge of the ancient rocks of Nili Fossae. Refs:Barnes, S. J. "Komatiites: Petrology, Volcanology, Metamorphism, and Geochemistry." S.E.G. 13 (2007): 13. Brown, A. J., et al.. "Hydrothermal Formation of Clay-Carbonate Alteration Assemblages in the Nili Fossae Region of Mars." EPSL 297 (2010): 174-82. Ehlmann, B. L. et al. "Orbital Identification of Carbonate-Bearing Rocks on Mars." Science 322, no. 5909 1828-32. Van Kranendonk, M.J., and F. Pirajno. "Geochemistry of Metabasalts and Hydrothermal

  6. Source-rock evaluation of the Dakhla Formation black shale in Gebel Duwi, Quseir area, Egypt

    NASA Astrophysics Data System (ADS)

    El Kammar, M. M.

    2015-04-01

    A relatively thick Upper Cretaceous-Lower Tertiary sedimentary succession is exposed in Gebel Duwi, Red Sea area, through an almost horizontal tunnel cutting the NE dipping strata from Quseir to Thebes formations. The black shale belonging to Dakhla Formation represents a real potential for future energy resource for Egypt. Dakhla Formation consists mainly of organic-rich calcareous shale to argillaceous limestone that can be considered as a good to excellent source rock potential. The total organic carbon (TOC) content ranges from 2.04% to 12.08%, and the Hydrogen Index (HI) values range from 382 to 1024 mg HC/g TOC. Samples of the Dakhla Formation contain mostly kerogen of types I and II that prone oil and oil-gas, indicating marine organic matter derived mainly from algae and phytoplankton organisms and proposing typical oil source kerogen. The average of the potential index (PI) value is 0.02 mg HC/g rock, which indicates the beginning of a considerable amount of oil generation from the Dakhla Formation. The Tmax values range from 427 to 435 °C. Based on the Tmax data and PI values, the studied black shale samples are immature to early mature for hydrocarbon generation in the Duwi area. The data reduction suggests four main factors covering about 91% of the total variances. The average of the calorific value (459 kcal/kg) indicates unworkable efficiency of such black shale for direct combustion use in power stations. However, selective operation of specific horizons having the highest calorific values may provide viable resources.

  7. Evaluating the Biological Influences on Ooid Formation in the Great Salt Lake, Utah

    NASA Astrophysics Data System (ADS)

    Bird, J. T.; Stefurak, E. J.; Anderson, R. P.; Meneske, M.; Berelson, W.; Sessions, A. L.; Osburn, M. R.; Spear, J. R.; Stamps, B. W.; Stevenson, B.; Shapiro, R. S.; Torres, M. A.; Corsetti, F. A.

    2013-12-01

    Recent studies from the Bahamas and Shark Bay imply microbial influence on ooid formation based on both 16S-rRNA and lipid biomarkers [1,2]. The Great Salt Lake, Utah, provides an opportunity to assess the possible role of microbes in ooid formation because of its unique environmental setting: the lake is divided into the more saline North Arm (NA) and the less saline South Arm (SA). The microbial community of the NA ooids was dominated by members of the Halobacteria, Gammaproteobacteria, and Bacteriodetes. The diversity of the surrounding water was identical to that of the NA ooids. The community from the SA ooids, dominated by Bacteriodetes, Alphaproteobacteria, and Gammaproteobacteria, was distinct from that of the surrounding water, which was dominated by Halobacteria, Gammaproteobacteria, and Bacteriodetes. OTUs related to Bacteriodetes and Gammaproteobacteria in SA ooids differed from the surrounding water and NA ooids. While ooid fabrics from the NA and SA were identical, their microbial communities differed which indicates the variance in diversity exerts no obvious control on ooid morphology. In addition, the microbial communities of the Great Salt Lake shared few similarities with those of recently examined ooids in the Bahamas and Shark Bay. The Great Salt Lake is supersaturated with respect to calcite, aragonite, and dolomite, suggesting that carbonate precipitation need not require biological mediation. However, we did identify taxa that can alter the local saturation state of calcium carbonate (e.g., Desulfohalobiaceae and Ectothiorhodospiraceae), although they were different between the two sites. Intriguingly, the ooids contain a significant amount of sulfur (up to 0.15 wt. %). The microbial communities observed, which include sulfate reducers and sulfide oxidizers, could facilitate this sulfur formation and in doing so provide a significant boost to the local alkalinity. We hypothesize that this observed microbial community could influence ooid

  8. Composition and secondary formation of fine particulate matter in the Salt Lake Valley: winter 2009.

    PubMed

    Kuprov, Roman; Eatough, Delbert J; Cruickshank, Tyler; Olson, Neal; Cropper, Paul M; Hansen, Jaron C

    2014-08-01

    Under the National Ambient Air Quality Standards (NAAQS), put in place as a result of the Clean Air Amendments of 1990, three regions in the state of Utah are in violation of the NAAQS for PM10 and PM2.5 (Salt Lake County, Ogden City, and Utah County). These regions are susceptible to strong inversions that can persist for days to weeks. This meteorology, coupled with the metropolitan nature of these regions, contributes to its violation of the NAAQS for PM during the winter. During January-February 2009, 1-hr averaged concentrations of PM10-2.5, PM2.5, NO(x), NO2, NO, O3, CO, and NH3 were measured. Particulate-phase nitrate, nitrite, and sulfate and gas-phase HONO, HNO3, and SO2 were also measured on a 1-hr average basis. The results indicate that ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited. Overall, the lower boundary layer in the Salt Lake Valley appears to be oxidant and volatile organic carbon (VOC) limited with respect to ozone formation. The most effective way to reduce ammonium nitrate secondary particle formation during the inversions period is to reduce NO(x) emissions. However, a decrease in NO(x) will increase ozone concentrations. A better definition of the complete ozone isopleths would better inform this decision. Implications: Monitoring of air pollution constituents in Salt Lake City, UT, during periods in which PM2.5 concentrations exceeded the NAAQS, reveals that secondary aerosol formation for this region is NO(x) limited. Therefore, NO(x) emissions should be targeted in order to reduce secondary particle formation and PM2.5. Data also indicate that the highest concentrations of sulfur dioxide are associated with winds from the north-northwest, the location of several small refineries. PMID:25185397

  9. Bacterially-Mediated Formation of Rock Coatings in Karkevagge, Swedish Lapland: A Mineralogical and Micro-Environmental Analog for Mars

    NASA Astrophysics Data System (ADS)

    Marnocha, Cassandra L.

    The search for past or present life on Mars is, for now, limited to surface environments. An often neglected surface environment that could have served as an abode for life and could presently preserve evidence of that life is that of rock coatings. Rock coatings are mineral accretions on rock surfaces. On Earth, they are widespread and occur with considerable chemical diversity. There is growing evidence for a biotic role in their formation on Earth, particularly with respect to rock varnish. As a result, rock varnish has become a target of astrobiological interest on Mars, where varnish-like coatings have been observed. However, a number of coating types compatible with martian mineralogy exist but have yet to be investigated thoroughly. In this dissertation, I present a study of three principle rock coating types from a glacially eroded valley, Karkevagge, in northern Sweden. The coatings consist of iron films, sulfate crusts, and aluminum glazes, all with primary mineralogies that are compatible with those minerals that have been identified on Mars. To examine the role of microbiology in these terrestrial rock coatings and what the biotic formation of coatings might tell us about observed coatings on Mars, we asked three basic questions: 1) What microbes inhabit the coatings, 2) What are those microbes contributing to the geochemistry of the coatings, and 3) How are the microbes contributing to the overall formation of the rock coating? To answer these questions, we undertook two bacterial diversity surveys - Sanger sequencing and 454 pyrosequencing. Using the results of these surveys, we were able to assess diversity, richness, and metabolic potential of the communities. Microscopy and spectroscopy were used in order to visualize microbial communities inhabiting the coatings and to observe evidence of biomineralization. Using the answers to those questions - who, what, and how - a conceptual model of coating formation was developed to relate the terrestrial

  10. Dynamics of Asp23-Lys28 salt-bridge formation in Abeta10-35 monomers.

    PubMed

    Tarus, Bogdan; Straub, John E; Thirumalai, D

    2006-12-20

    In the amyloid fibrils formed from long fragments of the amyloid beta-protein (Abeta-protein), the monomers are arranged in parallel and lie perpendicular to the fibril axis. The structure of the monomers satisfies the amyloid self-organization principle; namely, the low free energy state of the monomer maximizes the number of intra- and interpeptide contacts and salt bridges. The formation of the intramolecular salt bridge between Asp(D)23 and Lys(K)28 ensures that unpaired charges are not buried in the low-dielectric interior. We have investigated, using all-atom molecular dynamics simulations in explicit water, whether the D23-K28 interaction forms spontaneously in the isolated Abeta10-35 monomer. To validate the simulation protocol, we show, using five independent trajectories spanning a total of 100 ns, that the pKa values of the titratable groups are in good agreement with experimental measurements. The computed free energy disconnectvity graph shows that broadly the ensemble of compact random coil conformations can be clustered into four basins that are separated by free energy barriers ranging from 0.3 to 2.7 kcal/mol. There is significant residual structure in the conformation of the peptide in each of the basins. Due to the desolvation penalty, the structural motif with a stable turn involving the residues VGSN and a preformed D23-K28 contact is a minor component of the simulated structures. The extent of solvation of the peptides in the four basins varies greatly, which underscores the dynamical fluctuations in the monomer. Our results suggest that the early event in the oligomerization process must be the expulsion of discrete water molecules that facilitates the formation of interpeptide-interaction-driven stable structures with an intramolecular D23-K28 salt bridge and an intact VGSN turn. PMID:17165769

  11. Complex igneous processes and the formation of the primitive lunar crustal rocks

    NASA Technical Reports Server (NTRS)

    Longhi, J.; Boudreau, A. E.

    1979-01-01

    Crystallization of a magma ocean with initial chondritic Ca/Al and REE ratios such as proposed by Taylor and Bence (TB, 1975), is capable of producing the suite of primitive crustal rocks if the magma ocean underwent locally extensive assimilation and mixing in its upper layers as preliminary steps in formation of an anorthositic crust. Lunar anorthosites were the earliest permanent crustal rocks to form the result of multiple cycles of suspension and assimilation of plagioclase in liquids fractionating olivine and pyroxene. There may be two series of Mg-rich cumulate rocks: one which developed as a result of the equilibration of anorthositic crust with the magma ocean; the other which formed in the later stages of the magma ocean during an epoch of magma mixing and ilmenite crystallization. This second series may be related to KREEP genesis. It is noted that crystallization of the magma ocean had two components: a low pressure component which produced a highly fractionated and heterogeneous crust growing downward and a high pressure component which filled in the ocean from the bottom up, mostly with olivine and low-Ca pyroxene.

  12. Formation of Quartz-Carbonate Veins: Evidence From Experimental Supercritical Carbon Dioxide-Brine-Rock System

    NASA Astrophysics Data System (ADS)

    Janecky, D. R.; Kaszuba, J. P.

    2003-12-01

    Quartz-carbonate veins are common in a variety of moderate temperature hydrothermal systems and ore deposits. Associated fluid inclusions have a wide range of compositions, including liquid carbon dioxide fillings. Examination of chemical and physical conditions which result precipitation of quartz and carbonate in veins raises several key questions about multiphase fluid processes and reaction rates. We have been experimentally investigating physical-chemical reaction processes of mixed brine-carbon dioxide fluids for the shallow crust. Synthetic arkose (microcline + oligoclase + quartz + biotite) plus argillaceous shale were reacted with 5.5 molal NaCl brine. The system was held at 200 C and 200 bars for 32 days to approach steady state, then injected with carbon dioxide and allowed to react for an additional 45 days. In a parallel experiment, the system was allowed to react for 77 days without injection of carbon dioxide. Trace ions initially absent from NaCl brine appeared in solution at mM (K, Ca, and silica) to uM (Mg, Al, Fe and Mn) quantities, reflecting reaction of brine with rock. Without carbon dioxide injection, the silica concentration (2.4 mM) was stable below calculated quartz solubility (3.9 mM). Injection of carbon dioxide resulted in decreased pH and increased silica concentration to a level near calculated chalcedony solubility (5.4 mM). Dissolution of silicate minerals is apparently coupled to the acidity, and concomitant inhibition of the precipitation of quartz (and other silicates). A significant increase in concentration of trace metals is consistent with in-situ pH decrease and increased carbon dioxide dissolved in brine. Multi-phase fluid reaction relationships between supercritical carbon dioxide and brine-rock systems allow formation of carbonate vein precipitates in substantial quantities. Brine and continued rock reactions provide a substantial reservoir for Ca, Mg and Fe components. A separate carbon dioxide liquid allows

  13. Constitutive representation of damage development and healing in WIPP salt

    SciTech Connect

    Chan, K.S.; Bodner, S.R.; Fossum, A.F

    1994-12-31

    There has been considerable interest in characterizing and modeling the constitutive behavior of rock salt with particular reference to long-term creep and creep failure. The interest is motivated by the projected use of excavated rooms in salt rock formations as repositories for nuclear waste. It is presumed that closure of those rooms by creep ultimately would encapsulate the waste material, resulting in its effective isolation. A continuum mechanics approach for treating damage healing is formulated as part of a constitutive model for describing coupled creep, fracture, and healing in rock salt. Formulation of the healing term is, described and the constitutive model is evaluated against experimental data of rock salt from the Waste Isolation Pilot Plant (WIPP) site. The results indicate that healing anistropy in WIPP salt can be modeled with an appropriate power-conjugate equivalent stress, kinetic equation, and evolution equation for damage healing.

  14. Alkaline fluid circulation in ultramafic rocks and formation of nucleotide constituents: a hypothesis

    PubMed Central

    Holm, Nils G; Dumont, Marion; Ivarsson, Magnus; Konn, Cécile

    2006-01-01

    Seawater is constantly circulating through oceanic basement as a low-temperature hydrothermal fluid (<150°C). In cases when ultramafic rocks are exposed to the fluids, for instance during the initial phase of subduction, ferromagnesian minerals are altered in contact with the water, leading to high pH and formation of secondary magnesium hydroxide, among other – brucite, that may scavenge borate and phosphate from seawater. The high pH may promote abiotic formation of pentoses, particularly ribose. Pentoses are stabilized by borate, since cyclic pentoses form a less reactive complex with borate. Analyses have shown that borate occupies the 2' and 3' positions of ribose, thus leaving the 5' position available for reactions like phosphorylation. The purine coding elements (adenine, in particular) of RNA may be formed in the same general hydrothermal environments of the seafloor. PMID:16867193

  15. Paleomagnetic and rock-magnetic studies of the Permian Cutler and Elephant Canyon formations in Utah.

    NASA Technical Reports Server (NTRS)

    Gose, W. A.; Helsley, C. E.

    1972-01-01

    Study of the Permian Cutler formation and the upper 15 meters of the Permian Elephant Canyon formation at 0.6-meter stratigraphic intervals southwest of Moab in eastern Utah. The directions of natural remanent magnetization show a pronounced streak distribution, but thermal demagnetization successfully isolates the stable paleomagnetic direction. All directions are reversed, and no significant long-term change in pole position is observed throughout the entire section. The pole calculated from the Elephant Canyon data lies at 43.6 N, 119.6 E; the Cutler pole lies at 44.4 N, 116.2 E. Rock-magnetic analyses suggest that the secondary magnetization results from the iron hydroxides and was acquired after recent surface exposure.

  16. Rock physics model-based prediction of shear wave velocity in the Barnett Shale formation

    NASA Astrophysics Data System (ADS)

    Guo, Zhiqi; Li, Xiang-Yang

    2015-06-01

    Predicting S-wave velocity is important for reservoir characterization and fluid identification in unconventional resources. A rock physics model-based method is developed for estimating pore aspect ratio and predicting shear wave velocity Vs from the information of P-wave velocity, porosity and mineralogy in a borehole. Statistical distribution of pore geometry is considered in the rock physics models. In the application to the Barnett formation, we compare the high frequency self-consistent approximation (SCA) method that corresponds to isolated pore spaces, and the low frequency SCA-Gassmann method that describes well-connected pore spaces. Inversion results indicate that compared to the surroundings, the Barnett Shale shows less fluctuation in the pore aspect ratio in spite of complex constituents in the shale. The high frequency method provides a more robust and accurate prediction of Vs for all the three intervals in the Barnett formation, while the low frequency method collapses for the Barnett Shale interval. Possible causes for this discrepancy can be explained by the fact that poor in situ pore connectivity and low permeability make well-log sonic frequencies act as high frequencies and thus invalidate the low frequency assumption of the Gassmann theory. In comparison, for the overlying Marble Falls and underlying Ellenburger carbonates, both the high and low frequency methods predict Vs with reasonable accuracy, which may reveal that sonic frequencies are within the transition frequencies zone due to higher pore connectivity in the surroundings.

  17. Special core analyses and relative permeability measurement on Almond formation reservoir rocks

    SciTech Connect

    Maloney, D.; Doggett, K.; Brinkmeyer, A.

    1993-02-01

    This report describes the results from special core analyses and relative permeability measurements conducted on samples of rock from the Almond Formation in Greater Green River Basin of southwestern Wyoming. The core was from Arch Unit Well 121 of Patrick Draw field. Samples were taken from the 4,950 to 4,965 ft depth interval. Thin section evaluation, X-ray diffraction, routine permeability and porosity, capillary pressure and wettability tests were performed to characterize the samples. Fluid flow capacity characteristics were measured during two-phase unsteady- and steady-state and three-phase steady-state relative permeability tests. Test results are presented in tables and graphs. Relative permeability results are compared with those of a 260-mD, fired Berea sandstone sample which was previously subjected to similar tests. Brine relative permeabilities were similar for the two samples, whereas oil and gas relative permeabilities for the Almond formation rock were higher at equivalent saturation conditions compared to Berea results. Most of the tests described in this report were conducted at 74[degrees]F laboratory temperature. Additional tests are planned at 150[degrees]F temperature. Equipment and procedural modifications to perform the elevated temperature tests are described.

  18. Special core analyses and relative permeability measurement on Almond formation reservoir rocks

    SciTech Connect

    Maloney, D.; Doggett, K.; Brinkmeyer, A.

    1993-02-01

    This report describes the results from special core analyses and relative permeability measurements conducted on samples of rock from the Almond Formation in Greater Green River Basin of southwestern Wyoming. The core was from Arch Unit Well 121 of Patrick Draw field. Samples were taken from the 4,950 to 4,965 ft depth interval. Thin section evaluation, X-ray diffraction, routine permeability and porosity, capillary pressure and wettability tests were performed to characterize the samples. Fluid flow capacity characteristics were measured during two-phase unsteady- and steady-state and three-phase steady-state relative permeability tests. Test results are presented in tables and graphs. Relative permeability results are compared with those of a 260-mD, fired Berea sandstone sample which was previously subjected to similar tests. Brine relative permeabilities were similar for the two samples, whereas oil and gas relative permeabilities for the Almond formation rock were higher at equivalent saturation conditions compared to Berea results. Most of the tests described in this report were conducted at 74{degrees}F laboratory temperature. Additional tests are planned at 150{degrees}F temperature. Equipment and procedural modifications to perform the elevated temperature tests are described.

  19. Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines

    NASA Astrophysics Data System (ADS)

    Navarrete, Ian A.; Tsutsuki, Kiyoshi; Asio, Victor B.; Kondo, Renzo

    2009-09-01

    This study was conducted to evaluate the physical, chemical, and mineralogical characteristics of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Four sites along a catena were selected at an elevation of 75-112 m above sea level with an average annual rainfall of 3,000 mm and an average temperature of 28°C. Results indicate that the soils are deep, clayey, and reddish in color, which is indicative of the advanced stage of soil development. They also posses excellent physical condition (friable and highly porous) although they are plastic and sticky when wet as is usual for clayey soils. In terms of chemical characteristics, the soils are acidic with low CEC values and generally low in organic matter and nutrient contents. The clay mineralogy of the soils is dominated by halloysite and kaolinite with minor amounts of goethite and hematite, and they also have generally high dithionite-extractable Fe contents confirming the advanced stage of their development. The soils in the more stable slope positions (PL-1, PL-2, and PL-4) have generally similar characteristics and appeared more developed than the one in the less stable position (PL-3). The most important pedogenic processes that formed the soils appear to be weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The nature of the parent rock and climatic conditions prevailing in the area as well as slope position appear to have dominant effects on the development of the soils.

  20. Lithium-bearing rocks of the Horse Spring Formation, Clark County, Nevada

    USGS Publications Warehouse

    Brenner-Tourtelot, E. F.; Glanzman, R.K.

    1978-01-01

    The Horse Spring Formation of Miocene age in Clark County, Nevada, contains as much as 0.5% Li in individual samples. Rock sequences which average 0.1% Li range from 3 m thick near Gold Butte (south of Mesquite, Nev.) to as much as 40 m thick near Lava Butte (east of Las Vegas, Nev.) about 75 km to the west. The lithium-bearing beds are light colored to white and contain hectorite in a dolomite, magnesite, or calcite matrix. Varied amounts of gypsum, halite, celestite, clinoptilolite, quartz, feldspar, biolite and colemanite are also present locally. Hectorite is the only lithium mineral recognized to date. The lithium-rich rocks contain low concentrations of most other minor elements except that boron and strontium are enriched. Rarely, barium, arsenic, and zinc are present in anomalously large amounts. The lithium-enriched part of the Horse Spring Formation was formed from a series of volcanic ashes which were deposited in a playa. Relict volcanic ash is recognizable in thin sections as remnant glass shards and vitroclastic textures. Most of the original glass has been altered to clay minerals, carbonate minerals, or zeolites, presumably through interaction with highly saline pore waters. Abundant evidence of spring activity suggests that thermal waters played a part in releasing the lithium from volcanic materials. ?? 1978.

  1. Salt lakes of Western Australia - Natural abiotic formation of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Krause, T.; Studenroth, S.; Mulder, I.; Tubbesing, C.; Kotte, K.; Ofner, J.; Junkermann, W.; Schöler, H. F.

    2012-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many ephemeral saline and hypersaline lakes with a wide range of hydrogeochemical parameters that have gradually changed over the last fifty years. Historically, the region was covered by eucalyptus trees and shrubs, but was cleared mainly within 10 years after WWII to make room for wheat and live stock. After the clearance of the deep rooted native plants the groundwater started to rise, bringing increased amounts of dissolved salts and minerals to the surface and discharging them into streams and lakes. Thus most of Western Australia is influenced by secondary salinisation (soil salting) [1]. Another problem is that the discharged minerals affect the pH of ground and surface water, which ranges from acidic to slightly basic. During the 2011 campaign surface water was measured with a pH between 2.5 and 7.1. Another phenomenon in Western Australia is the decrease of rainfall over the last decades assumed to be linked to the secondary salinisation. The rising saline and mineral rich groundwater increases the biotical and abiotical activity of the salt lakes. Halogenated and non-halogenated volatile organic compounds emitted from those lakes undergo fast oxidation and chemical reactions to form small particles modifying cloud microphysics and thus suppressing rain events [2]. Our objective is to gain a better understanding of this extreme environment with its hypersaline acidic lakes with regard to the potential abiotic formation of volatile organic compounds and its impact on the local climate. In spring 2011 fifty-three sediment samples from ten salt lakes in the Lake King region where taken, freeze-dried and ground. In order to simulate the abiotic formation of volatile organic compounds the soil samples were resuspended with water in gas-tight headspace vials. The headspace was measured using a purge and trap GC

  2. Rubisco decrease is involved in chloroplast protrusion and Rubisco-containing body formation in soybean (Glycine max.) under salt stress.

    PubMed

    He, Yi; Yu, Chenliang; Zhou, Li; Chen, Yue; Liu, Ao; Jin, Junhua; Hong, Jian; Qi, Yanhua; Jiang, Dean

    2014-01-01

    Salt stress often induces declination of net photosynthetic rate (Pn), partially resulted from Rubisco degradation. The chloroplast protrusions (CPs) is one of the pathways of Rubisco exclusion from chloroplasts. To explore the relationship between the Rubisco contents and CPs under salt stress, Pn, maximum photochemical efficiency of PSII (F(v)/F(m)), carboxylation efficiency (CE) and concentration of Rubisco, number of CPs and Rubisco-containing Body (RCBs) were investigated with two differently salt-responding varieties in this experiment. We observed that 150 mM salt treatment resulted in not only significant decrease in Pn, CE and Rubisco content, but also obvious increase in the number of CPs and RCBs in salt-sensitive variety. Under salt stress formation of CPs resulted in production of much more RCBs, which could immigrate into and combine with vacuole. It may be a kind of important mechanism for rapid degradation of Rubisco under salt stress. Our conclusion provides a new sight for how Rubisco can be fast degraded under salt stress. PMID:24291158

  3. How Sodium Chloride Salt Inhibits the Formation of CO2 Gas Hydrates.

    PubMed

    Holzammer, Christine; Finckenstein, Agnes; Will, Stefan; Braeuer, Andreas S

    2016-03-10

    We present an experimental Raman study on how the addition of sodium chloride to CO2-hydrate-forming systems inhibits the hydrate formation thermodynamically. For this purpose, the molar enthalpy of reaction and the molar entropy of reaction for the reaction of weakly hydrogen-bonded water molecules to strongly hydrogen bonded water molecules are determined for different salinities from the Raman spectrum of the water-stretching vibration. Simultaneously, the influence of the salinity on the solubility of CO2 in the liquid water-rich phase right before the start of hydrate formation is analyzed. The results demonstrate that various mechanisms contribute to the inhibition of gas hydrate formation. For the highest salt concentration of 20 wt % investigated, the temperature of gas hydrate formation is lowered by 12 K. For this concentration the molar enthalpy and entropy of reaction become smaller by 50 and 20%, respectively. Concurrently, the solubility of carbon dioxide is reduced by 70%. These results are compared with data in literature for systems of sodium chloride in water (without carbon dioxide). PMID:26867107

  4. Methylammonium methylcarbamate thermal formation in interstellar ice analogs: a glycine salt precursor in protostellar environments

    NASA Astrophysics Data System (ADS)

    Bossa, J.-B.; Duvernay, F.; Theulé, P.; Borget, F.; D'Hendecourt, L.; Chiavassa, T.

    2009-11-01

    Context: Analyses of dust cometary grains collected by the Stardust spacecraft have shown the presence of amines and amino acids molecules, and among them glycine (NH{2}CH{2}COOH). We show how the glycine molecule could be produced in the protostellar environments before its introduction into comets. Aims: We study the evolution of the interstellar ice analogues affected by both thermal heating and vacuum ultraviolet (VUV) photons, in addition to the nature of the formed molecules and the confrontation of our experimental results with astronomical observations. Methods: Infrared spectroscopy and mass spectrometry are used to monitor the evolution of the H{2}O:CO{2}:CH{3}NH{2} and CO{2}:CH{3}NH{2} ice mixtures during both warming processes and VUV photolysis. Results: We first show how carbon dioxide (CO{2}) and methylamine (CH{3}NH{2}) thermally react in water-dominated ice to form methylammonium methylcarbamate [ CH{3}NH{3}+] [ CH{3}NHCOO-] noted C. We then determine the reaction rate and activation energy. We show that C thermal formation can occurs in the 50-70 K temperature range of a protostellar environment. Secondly, we report that a VUV photolysis of a pure C sample produces a glycine salt, methylammonium glycinate [ CH{3}NH{3}+] [ NH{2}CH{2}COO-] noted G. We propose a scenario explaining how C and subsequently G can be synthesized in interstellar ices and precometary grains. Conclusions: [ CH{3}NH{3}+] [ CH{3}NHCOO-] could be readily formed and would act as a glycine salt precursor in protostellar environments dominated by thermal and UV processing. We propose a new pathway leading to a glycine salt, which is consistent with the detection of glycine and methylamine within the returned samples of comet 81P/Wild 2 from the Stardust mission.

  5. Formation and preservation of biotite-rich microdomains in high-temperature rocks from the Antananarivo Block, Madagascar

    NASA Astrophysics Data System (ADS)

    Cenki-Tok, Bénédicte; Berger, Alfons; Gueydan, Frédéric

    2016-07-01

    Highly restitic rocks from the Antananarivo Block in northern Madagascar are investigated in this study in order to unravel processes of H2O-rich biotite formation in HT rocks. Polyphase metamorphism and melt migration occurred at 0.6 GPa and 850 °C. Biotite remains stable together with orthopyroxene and makes up to 45 vol% of the rock. In addition, three well-characterised and delimited microdomains having different textural, chemical and petrological characteristics are preserved. Thermodynamic models using the specific bulk compositions of the domains are in agreement with petrological observations. These rocks provide evidence that the lower crust may be strongly heterogeneous, locally associated to the formation of hydrous restites controlled by episodes of melt production and melt escape. This has significant consequences for understanding of the lower crust.

  6. Rock Formation and Cosmic Radiation Exposure Ages in Gale Crater Mudstones from the Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Mahaffy, Paul; Farley, Ken; Malespin, Charles; Gellert, Ralph; Grotzinger, John

    2014-05-01

    The quadrupole mass spectrometer (QMS) in the Sample Analysis at Mars (SAM) suite of the Mars Science Laboratory (MSL) has been utilized to secure abundances of 3He, 21Ne, 36Ar, and 40Ar thermally evolved from the mudstone in the stratified Yellowknife Bay formation in Gale Crater. As reported by Farley et al. [1] these measurements of cosmogenic and radiogenic noble gases together with Cl and K abundances measured by MSL's alpha particle X-ray spectrometer enable a K-Ar rock formation age of 4.21+0.35 Ga to be established as well as a surface exposure age to cosmic radiation of 78+30 Ma. Understanding surface exposures to cosmic radiation is relevant to the MSL search for organic compounds since even the limited set of studies carried out, to date, indicate that even 10's to 100's of millions of years of near surface (1-3 meter) exposure may transform a significant fraction of the organic compounds exposed to this radiation [2,3,4]. Transformation of potential biosignatures and even loss of molecular structural information in compounds that could point to exogenous or endogenous sources suggests a new paradigm in the search for near surface organics that incorporates a search for the most recently exposed outcrops through erosional processes. The K-Ar rock formation age determination shows promise for more precise in situ measurements that may help calibrate the martian cratering record that currently relies on extrapolation from the lunar record with its ground truth chronology with returned samples. We will discuss the protocol for the in situ noble gas measurements secured with SAM and ongoing studies to optimize these measurements using the SAM testbed. References: [1] Farley, K.A.M Science Magazine, 342, (2013). [2] G. Kminek et al., Earth Planet Sc Lett 245, 1 (2006). [3] Dartnell, L.R., Biogeosciences 4, 545 (2007). [4] Pavlov, A. A., et al. Geophys Res Lett 39, 13202 (2012).

  7. Preliminary hydrocarbon source rock assessment of the Paleozoic and Mesozoic formations of the western Black Sea region of Turkey

    SciTech Connect

    Harput, B.O.; Demirel, I.H.; Karayigit, A.I.; Aydin, M.; Sahintuerk, O.; Bustin, R.M.

    1999-12-01

    Source rock maturity and potential of Paleozoic and Mesozoic formations in the Eregli, Zonguldak, Bartin, Ulus, and Eflani subregions of the western Black Sea region (WBSR), have been investigated by rock-eval pyrolysis, reflected-light microscopy, and palynofacies analyses. The % Ro values of dispersed organic matter of the Paleozoic formations primarily range from 0.72 to 1.8%, but values as high as 2.6% occur locally in the Silurian Findikli Formation in the Eregli subregion. The % Ro values of Namurian-Westphalian coal seams in the K20/H well drilled in the Zonguldak subregion range from 0.87 to 1.52%, with increasing depth consistent with sedimentary depth of burial. Most Cretaceous age samples have reflectance values ranging from 0.44 to 1.6% Ro that indicates they are marginally mature to mature with respect to the oil window. Rock-eval pyrolysis demonstrates that the Paleozoic formations have limited oil-generation potential (HI values {le} 200 mg HC/g C{sub org}), but good gas potential (TOC values up to 3%). Cretaceous formations have better petroleum source rock characteristics, but they too are primarily gas prone. Variations in the source rock maturity probably reflect variable burial histories in different localities of the WBSR.

  8. Rheological stratification in Zechstein rock salt caused by thermodynamically controlled reorganization of grain boundary fluids? A test using gravitationally induced sinking of anhydrite-dolomite stringers.

    NASA Astrophysics Data System (ADS)

    Urai, Janos L.; Raith, Alexander F.

    2016-04-01

    The rheology of rock salt during slow deformation in nature is controlled by the dominant deformation mechanism. Newtonian viscous rheology is associated with solution precipitation processes, while power law rheology is associated with dislocation creep. In large strain deformation during salt tectonics these two processes both contribute equally to the total strain rate, and grain boundaries contain mobile brine films. It has been shown that after the end of active salt tectonics, these fluid films neck down into arrays of disconnected brine inclusions, rendering the grain boundaries immobile and thus stopping solution-precipitation creep. This results in very low gravitational sinking rates of isolated anhydrite-dolomite stringers in Zechstein salt in the Tertiary, consistent with power law creep, while in Newtonian salt the stringers would sink to the bottom in geologically short time. In a recent paper Ghanbarzadeh et al., (Science, Nov 2015) provided evidence that below approximately 2 km depth the thermodynamically controlled dihedral angle between solid-liquid and solid-solid grain boundaries decreases to below 60 degrees, so that a connected grain boundary triple junction network of fluid channels is formed and permeability of the salt increases. The same process can be argued to lead to permanently mobile grain boundaries below this critical depth, activating solution-precipitation creep even in the absence of active tectonics. We test this hypothesis by comparing estimated gravitationally induced sinking rates of isolated anhydrite-dolomite stringers in the Zechstein of NE-Netherlands, based on 3D sesmic data, at depths above and below this proposed transition. First results suggest that there is no significant change in stringer sinking rate with depth.

  9. The salt that wasn't there: Mudflat facies equivalents to halite of the Permian Rustler Formation, southeastern New Mexico

    SciTech Connect

    Powers, D.W.; Holt, R.M.

    2000-01-01

    Four halite beds of the Permian Restler Formation in southeastern New Mexico thin dramatically over horst lateral distances to correlative classic (mudstone) beds. The mudstones have long been considered residues after post-burial dissolution (subrosion) of halite, assumed to have been deposited continuously across the area. Hydraulic properties of the Culebra Dolomite Member have often been related to Rustler subrosion. In cores and three shafts at the Waste Isolation Pilot Plant (WIPP), however, these mudstones display flat bedding, graded bedding, cross-bedding, erosional contacts, and channels filled with intraformational conglomerates. Cutans indicate early stages of soil development during subaerial exposure. Smeared intraclasts developed locally as halite was removed syndepositionally during subaerial exposure. The authors interpret these beds as facies formed in salt-pan or hypersaline-lagoon, transitional, and mudflat environments. Halite is distributed approximately as it was deposited. Breccia in limited areas along one halite margin indicates post-burial dissolution, and these breccials are key to identifying areas of subrosion. A depositional model accounts for observed sedimentary features of Restler mudstones. Marked facies and thickness changes are consistent with influence by subsidence boundaries, as found in some modern continental evaporites. A subrosion model accounts for limited brecciated zones along (depositional)halite margins, but bedding observed in the mudstones would not survive 90% reduction in rock volume. Depositional margins for these halite beds will be useful in reconstructing detailed subsidence history of the Late Permian in the northern Delaware Basin, It also no longer is tenable to attribute large variations in Culebra transmissivity to Rustler subrosion.

  10. Factors influencing the formation of polybromide monoanions in solutions of ionic liquid bromide salts.

    PubMed

    Easton, Max E; Ward, Antony J; Chan, Bun; Radom, Leo; Masters, Anthony F; Maschmeyer, Thomas

    2016-03-01

    Six different bromide salts - tetraethylammonium bromide ([N2,2,2,2]Br, Br), 1-ethyl-1-methylpiperidinium bromide ([C2MPip]Br, Br), 1-ethyl-1-methylpyrrolidinium bromide ([C2MPyrr]Br, Br), 1-ethyl-3-methylimidazolium bromide ([C2MIm]Br, Br), 1-ethylpyridinium bromide ([C2Py]Br, Br), and 1-(2-hydroxyethyl)pyridinium bromide ([C2OHPy]Br, Br) - were studied in regards to their capacity to form polybromide monoanion products on addition of molecular bromine in acetonitrile solutions. Using complementary spectroscopic and computational methods for the examination of tribromide and pentabromide anion formation, key factors influencing polybromide sequestration were identified. Here, we present criteria for the targeted synthesis of highly efficient bromine sequestration agents. PMID:26890026