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Sample records for abundant fluid inclusions

  1. Fluid Inclusion Gas Analysis

    DOE Data Explorer

    Dilley, Lorie

    2013-01-01

    Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.

  2. The analysis of fluid inclusions in halite

    NASA Astrophysics Data System (ADS)

    Lazar, Boaz; Holland, Heinrich D.

    1988-02-01

    A technique has been developed to drill into fluid inclusions in halite, to extract the inclusion fluids, and to determine the concentration of all of the major and some of the minor constituents in these fluids. The minimum diameter of usable fluid inclusions is ca. 250 μm. After dilution, the fluids are analyzed by ion chromatography and coulometry. Uncertainties in the concentration of the major cations and anions is on the order of 4%. The analytical scheme provides much more precise analyses of inclusion fluids than have been available to date. The analyses are a useful starting point for reconstructing the composition of the seawater from which the evaporite brines evolved.

  3. Shock Re-equilibration of Fluid Inclusions

    NASA Technical Reports Server (NTRS)

    Madden, M. E. Elwood; Horz, F.; Bodnar, R. J.

    2004-01-01

    Fluid inclusions (microscopic volumes of fluid trapped within minerals as they precipitate) are extremely common in terrestrial minerals formed under a wide range of geological conditions from surface evaporite deposits to kimberlite pipes. While fluid inclusions in terrestrial rocks are nearly ubiquitous, only a few fluid inclusion-bearing meteorites have been documented. The scarcity of fluid inclusions in meteoritic materials may be a result of (a) the absence of fluids when the mineral was formed on the meteorite parent body or (b) the destruction of fluid inclusions originally contained in meteoritic materials by subsequent shock metamorphism. However, the effects of impact events on pre-existing fluid inclusions trapped in target and projectile rocks has received little study. Fluid inclusions trapped prior to the shock event may be altered (re-equilibrated) or destroyed due to the high pressures, temperatures, and strain rates associated with impact events. By examining the effects of shock deformation on fluid inclusion properties and textures we may be able to better constrain the pressure-temperature path experienced by terrestrial and meteoritic shocked materials and also gain a clearer understanding of why fluid inclusions are rarely found in meteorite samples.

  4. An overview on current fluid-inclusion research and applications

    USGS Publications Warehouse

    Chi, G.; Chou, I.-Ming; Lu, H.-Z.

    2003-01-01

    This paper provides an overview of some of the more important developments in fluid-inclusion research and applications in recent years, including fluid-inclusion petrography, PVTX studies, and analytical techniques. In fluid-inclusion petrography, the introduction of the concept of 'fluid-inclusion assemblage' has been a major advance. In PVTX studies, the use of synthetic fluid inclusions and hydrothermal diamond-anvil cells has greatly contributed to the characterization of the phase behaviour of geologically relevant fluid systems. Various analytical methods are being developed and refined rapidly, with the Laser-Raman and LA-ICP-MS techniques being particularly useful for volatile and solute analyses, respectively. Ore deposit research has been and will continue to be the main field of application of fluid inclusions. However, fluid inclusions have been increasingly applied to other fields of earth science, especially in petroleum geology and the study of magmatic and earth interior processes.

  5. Fluids in high- to ultrahigh-temperature metamorphism along collisional sutures: Record from fluid inclusions

    NASA Astrophysics Data System (ADS)

    Tsunogae, Toshiaki; Santosh, M.

    2011-08-01

    Petrographic studies and microthermometric investigations on fluid inclusions associated with high- to ultrahigh-temperature metamorphic rocks in three major Precambrian suture zones on the globe demonstrate the dominant occurrence of CO 2-rich fluids. These rocks form part of hot orogens developed along collisional plate boundaries. The sapphirine-quartz-bearing Mg-Al-rich rock from the Palghat-Cauvery Suture Zone, a trace of the Cambrian Gondwana suture zone in southern India, preserves evidence for a prograde high-pressure event and subsequent peak ultrahigh-temperature metamorphism along a clockwise path, and contains abundant CO 2-rich inclusions in corundum, garnet, and sapphirine. Most of the fluid inclusions are either primary or secondary and preserve low-density CO 2-rich fluids (0.569-0.807 g/cm 3). Similar low-density CO 2-rich fluid inclusions (0.853-0.953 g/cm 3) are also present in pelitic granulites from the Limpopo Complex of southern Africa, a Neoarchean granulite-facies orogen formed by continent-continent collision. In contrast, the garnet-orthopyroxene granulite from Tonagh Island in the Neoarchean Napier Complex in East Antarctica contains very high-density primary (1.095-1.129 g/cm 3) and secondary (0.960-1.179 g/cm 3) carbonic inclusions in garnet and quartz. The calculated isochores for the fluid inclusions from the Palghat-Cauvery Suture Zone and the Limpopo Complex yield significantly lower-pressure estimates than those predicted from peak metamorphic conditions. We interpret this as a result of significant density decrease due to rapid decompression along a clockwise P- T trajectory. In contrast, the estimated isochores for primary inclusions in garnet-orthopyroxene granulites from the Napier Complex are consistent with the peak P- T conditions estimated from mineral phase equilibria for the Tonagh Island rocks, suggesting that most of the fluid inclusions in these rocks did not undergo any marked effect of volume change and density

  6. Laser microprobe analyses of noble gas isotopes and halogens in fluid inclusions: Analyses of microstandards and synthetic inclusions in quartz

    USGS Publications Warehouse

    Böhlke, J.K.; Irwin, J.J.

    1992-01-01

    Ar, Kr, Xe, Cl, Br, I, and K abundances and isotopic compositions have been measured in microscopic fluid inclusions in minerals by noble gas mass spectrometry following neutron irradiation and laser extraction. The laser microprobe noble gas mass spectrometric (LMNGMS) technique was quantified by use of microstandards, including air-filled capillary tubes, synthetic basalt glass grains, standard hornblende grains, and synthetic fluid inclusions in quartz. Common natural concentrations of halogens (Cl, Br, and I) and noble gases (Ar and Kr) in trapped groundwaters and hydrothermal fluids can be analyzed simultaneously by LMNGMS in as little as 10-11 L of inclusion fluid, with accuracy and precision to within 5-10% for element and isotope ratios. Multicomponent element and isotope correlations indicate contaminants or persistent reservoirs of excess Xe and/or unfractionated air in some synthetic and natural fluid inclusion samples. LMNGMS analyses of natural fluid inclusions using the methods and calibrations reported here may be used to obtain unique information on sources of fluids, sources of fluid salinity, mixing, boiling (or unmixing), and water-rock interactions in ancient fluid flow systems. ?? 1992.

  7. Fluid and gas migration in the North German Basin: fluid inclusion and stable isotope constraints

    NASA Astrophysics Data System (ADS)

    Lüders, Volker; Reutel, Christian; Hoth, Peer; Banks, David A.; Mingram, Birgit; Pettke, Thomas

    2005-12-01

    inclusions and reservoirs is Corg-rich Carboniferous shales with high nitrogen content. Intensive interaction of brines with Carboniferous or even older shales is proposed from fluid inclusion data (enrichment in Li, Ba, Pb, Zn, Mg) and sulfur isotopic compositions of abundant anhydrite from fissures. The mainly light δ34S values of the fissure anhydrites suggest that sulfate is either derived through oxidation and re-deposition of biogenic sulfur or through mixing of SO{4/2-}-rich formation waters with variable amounts of dissolved biogenic sulfide. An igneous source for nitrogen seems to be unlikely since these rocks have low total nitrogen content and, furthermore, even extremely altered volcanic rocks from the study area do not show a decrease in total nitrogen content.

  8. Fluid inclusions in salt from the Rayburn and Vacherie domes, Louisiana

    USGS Publications Warehouse

    Roedder, Edwin; Belkin, H.E.

    1979-01-01

    Core samples from the Rayburn and Vacherie salt domes in Louisiana were examined for fluid inclusions, in connection with the possible use of such domes for nuclear waste storage sites. Three types of fluid inclusions were found, brine, compressed gas, and oil (in decreasing volume percent abundance). The total amount of such fluids is small, certainly < 0.1 vol. % and probably in the range 0.01 to 0.001 volume %, but the inclusions are highly erratic in distribution. Unlike many bedded salt deposits, the brine inclusions in this salt contain fluids that are not far from simple NaCl-H2O solutions, with very little of other ions. One of three possible explanations for such fluids is that fresh water penetrated the salt at some unknown time in the past and was trapped; if such entry of fresh water has occurred in the past, it might also occur again in the future.

  9. Fluid inclusion studies of ejected nodules from plinian eruptions of Mt. Somma-Vesuvius

    USGS Publications Warehouse

    Belkin, H.E.; de Vivo, B.

    1993-01-01

    Mt. Somma-Vesuvius (Naples, Italy) has erupted potassium-rich and silica-undersaturated products during a complicated history of plinian and non-plinian events. Coarse-grained cognate nodules are commonly found in the pyroclastics and are upper crustal in origin. We examined cumulate and subeffusive nodules from the 3800 y.B.P. Avellino. A.D. 79 Pompei, and A.D. 472 Pollena eruptions. Silicate-melt and liquid-vapor fluid inclusion studies in clinopyroxene from both types of nodules have been used to assess the fluids attending crystallization and to place constraints on the pressure and temperature of nodule formation. Thermometric and volumetric data from primary and pseudosecondary CO2-H2O and CO2 and coeval silicate-melt fluid inclusions indicate that they were trapped at a pressure of ???1 to ???2.5 kbar at ???1200??C. This suggests a crystallization depth of ???4 to ???10 km. The H2O-bearing fluid inclusions are abundant from plinian eruptions in contrast to non-plinian eruptions where H2O-bearing fluid inclusions were rare. The presence of primary H2O-CO2 fluid inclusions indicates that an immiscible, supercritical H2O-CO2 fluid was in the nodule-forming environment. The H2O-bearing fluid inclusions in plinian nodules may record a higher pre-eruptive H2O content in the bulk magma that is dramatically reflected in the eruption dynamics. ?? 1993.

  10. Using melt inclusions and fluid inclusions to track ore-metal behavior in magma-hydrothermal systems (Invited)

    NASA Astrophysics Data System (ADS)

    Lowenstern, J. B.; Audétat, A.

    2013-12-01

    Melt and fluid inclusions yield important clues to the history of igneous melts and their related hydrothermal ore deposits (1). Under ideal conditions, melt inclusions in volcanic rocks yield data on the actual concentrations of ore metals and volatiles during instantaneous snapshots of crystallization and degassing. Their varying compositions can directly reflect sequestration of ore-metals in fractionating minerals and/or exsolving brines and vapors. Frequently, scientists compare the concentration of volatile elements in melt inclusions with their abundance in devolatilized matrix glass. Though this provides an informative qualitative overview of volatility, it is essentially impossible to use such data to calculate thermodynamically relevant partition coefficients. The resulting partitioning ratio instead represents fractionation over a wide range of pressures, and compositions (for both exsolved fluid and silicate melt). Ideally, workers should identify co-entrapped fluid and glass inclusions to provide more thermodynamically meaningful partitioning ratios for volatile metals and gases (2,3). Unfortunately, the occurrence of fluid inclusions co-entrapped with silicate melt is relatively rare, and studies of synthetic fluid and melt inclusions may be the most practical means of exploring the effect of crystallization and degassing in 'natural' systems. As with melt inclusions, under ideal conditions, fluid inclusions in intrusive rocks represent the compositions of fluids generated within associated magmatic-hydrothermal fluid systems. Multiple generations of cross-cutting fractures may be generated, resulting in trails of secondary and pseudosecondary inclusions in igneous minerals, and primary and secondary inclusions in hydrothermal assemblages. Chemistry of the fluids preserved within different inclusion generations will change markedly due to changes in magmatic temperature and pressure and mixing of diverse external fluids from meteoric and metamorphic

  11. Synthetic fluid inclusions XX. Critical PTx properties of H2O-FeCl2 fluids

    NASA Astrophysics Data System (ADS)

    Steele-MacInnis, Matthew; Lecumberri-Sanchez, Pilar; Bodnar, Robert J.

    2015-01-01

    Iron chloride is a common and abundant component in hydrothermal fluids in many geologic environments, yet the thermodynamic and PTx properties of FeCl2-bearing aqueous fluids are poorly known. In this study we have used the synthetic fluid inclusion technique to characterize the PTx conditions along the critical curve of the system H2O-FeCl2. For a given temperature or salinity, the critical pressure in the H2O-FeCl2 system is lower than that in the H2O-NaCl system. In contrast, the critical curves of aqueous solutions of other divalent-cation chlorides, such as MgCl2 and CaCl2, are at higher pressure than that of NaCl solutions of equivalent temperature or salinity. The results of this study provide the first quantitative constraints on the PTx extent of liquid-vapor immiscibility for FeCl2-rich fluids. Owing to the low pressure along the critical curve compared to other common aqueous chloride systems, immiscibility of FeCl2-rich fluids appears to be limited to relatively low pressures, or relatively shallow levels in the crust, compared to other saline hydrothermal fluids.

  12. Fluid inclusion evidence for hydrothermal fluid evolution in the Darreh-Zar porphyry copper deposit, Iran

    NASA Astrophysics Data System (ADS)

    Nateghi, Arash; Hezarkhani, Ardeshir

    2013-09-01

    The Darreh-Zar porphyry copper deposit is associated with a quartz monzonitic-granodioritic-porphyritic stock hosted by an Eocene volcanic sedimentary complex in which magmatic hydrothermal fluids were introduced and formed veins and alteration. Within the deepest quartz-rich and chalcopyrite-poor group A veins, LVHS2 inclusions trapped high salinity, high temperature aqueous fluids exsolved directly from a relatively shallow magma (0.5 kbar). These late fluids were enriched in NaCl and reached halite saturation as a result of the low pressure of magma crystallization and fluid exsolution. These fluids extracted Cu from the crystallizing melt and transported it to the hydrothermal system. As a result of ascent, the temperature and pressure of these fluids decreased from 600 to 415 °C, and approximately 500-315 bars. At these conditions, K-feldspar and biotite were stabilized. Type A veins were formed at a depth of ∼1.2 km under conditions of lithostatic pressure and abrupt cooling. Upon cooling and decompressing, the fluid intersected with the liquid-vapor field resulting in separation of immiscible liquid and vapor. This stage was recorded by formation of LVHS1, LVHS3 and VL inclusions. These immiscible fluids formed chalcopyrite-pyrite-quartz veins with sericitic alteration envelopes (B veins) under the lithostatic-hydrostatic pressure regime at temperatures between 415 and 355 °C at 1.3 km below the paleowater table. As the fluids ascended, copper contents decreased and these fluids were diluted by mixing with the low salinity-external fluid. Therefore, pyrite-dominated quartz veins were formed in purely hydrostatic conditions in which pressure decreased from 125 bars to 54 bars and temperature decreased from 355 to 298 °C. During the magmatic-hydrothermal evolution, the composition and P-T regime changed drastically and caused various types of veins and alterations. The abundance of chalcopyrite precipitation in group B veins suggests that boiling and

  13. The Chemical Behavior of Fluids Released during Deep Subduction Based on Fluid Inclusions

    NASA Astrophysics Data System (ADS)

    Frezzotti, M. L.; Ferrando, S.

    2014-12-01

    We present a review of current research on fluid inclusions in (HP-) UHP metamorphic rocks that, combined with existing experimental research and thermodynamic models, allow us to investigate the chemical and physical properties of fluids released during deep subduction, their solvent and element transport capacity, and the subsequent implications for the element recycling in the mantle wedge. An impressive number of fluid inclusion studies indicate three main populations of fluid inclusions in HP and UHP metamorphic rocks: i) aqueous and/or non-polar gaseous fluid inclusions (FI), ii) multiphase solid inclusions (MSI), and iii) melt inclusions (MI). Chemical data from preserved fluid inclusions in rocks match with and implement "model" fluids by experiments and thermodynamics, revealing a continuity behind the extreme variations of physico-chemical properties of subduction-zone fluids. From fore-arc to sub-arc depths, fluids released by progressive devolatilization reactions from slab lithologies change from relatively diluted chloride-bearing aqueous solutions (± N2), mainly influenced by halide ligands, to (alkali) aluminosilicate-rich aqueous fluids, in which polymerization probably governs the solubility and transport of major (e.g., Si and Al) and trace elements (including C). Fluid inclusion data implement the petrological models explaining deep volatile liberation in subduction zones, and their flux into the mantle wedge.

  14. Fluid inclusion geobarometry from ejected Mt. Somma-Vesuvius nodules.

    USGS Publications Warehouse

    Belkin, H.E.; de Vivo, B.; Roedder, E.; Cortini, M.

    1985-01-01

    The results of a microthermometric study of fluid inclusions from seven cumulate and three 'skarn' nodules collected from the pyroclastics of three non-Plinian eruptive episodes are presented. -J.A.Z.

  15. Fluid inclusions in quartz crystals from South-West Africa

    USGS Publications Warehouse

    Kvenvolden, K.A.; Roedder, E.

    1971-01-01

    Quartz crystals from calcite veins of unknown age in Precambrian metasedimentary rocks at Geiaus No. 6 and Aukam farms in South-West Africa contain both primary and secondary inclusions filled with one or a variable combination of: organic liquid, moderately saline aqueous liquid, dark-colored solid, and vapor. Analysis of these materials by microscopy and by gas chromatography and mass spectrometry shows the presence of constituents of both low and high molecular weights. The former include CH4, C2H6, C3H8 and possibly C4H10 as well as CO, CO2, H2O, N2 and H2. High molecular weight components are dominantly n-alkanes and isoprenoid hydrocarbons. The n-alkanes range from at least n-C10 to n-C33. Concentrations of n-alkanes larger than n-C17 decrease regularly with increasing carbon number. An homologous series of isoprenoid hydrocarbons ranging from at least C14 to C20 is present in unusually high concentrations. Pristane (C19) is most abundant, and C17 isoprenoid is least abundant. The molecular composition and distribution of hydrocarbons suggest biological precursors for these components. Consideration of data provided by freezing, crushing and heating experiments suggests that the pressures at the time these in part supercritical fluids were trapped probably exceeded 30-40 atm, and the minimum trapping temperature was about 120-160??C. Both primary and secondary inclusions apparently containing only organic materials were trapped by the growth of the host quartz from aqueous solution. The data obtained neither prove nor preclude Precambrian, Paleozoic or younger sources for the organic materials. ?? 1971.

  16. Fluid inclusions and microstructures in experimentally deformed quartz single crystals

    NASA Astrophysics Data System (ADS)

    Thust, A.; Tarantola, A.; Heilbronner, R.; Stünitz, H.

    2009-04-01

    to H2O loss into the healed cracks. First observations of deformed samples show abundant deformation lamellae. With higher deformation the lamellae form conjugated zones of high dislocation density and undulatory extinction. Micro cracks are frequently connected to fluid inclusions. Recrystallized grains are rare in deformed samples because of the low strain acquired. In semi-brittle experiments at lower temperature and faster strain rates considerable recrystallization features are visible and clearly connected to initial brittle deformation features. We conclude that fluid inclusion rupture and fast crack healing at high temperatures are necessary for the redistribution of H2O and a prerequisite of ductile deformation. References: Griggs, D.T. & Balcic, J.D. 1965: Quartz: anomalous weakness of synthetic crystals. Science 147, 293-295. FitzGerald, J.D., Boland, J.N., McLaren, A.C., Ord, A., Hobbs, B.E. 1991: Microstructures in water-weakened single crystals of quartz. Journal of Geophysical Research Vol. 96 No. B2, 2139-2155 Kronenberg, A.K. & Tullis, J. 1984: Flow strength of quartz aggregates: grain size and pressure effects due to hydrolytic weakening. Journal of Geophysical Research Vol.89, No. B6, 4281-4297. Kronenberg, A.K., Kirby, S.H., Aines, R.D., Rossman G.R. 1986: Solubility and diffusional uptake of hydrogen in quartz at high water pressures: implication for hydrolytic weakening. Journal of Geophysical Research Vol.91, NO. B12, 12,723-12,744. Paterson, M.S.1989: The interaction of water with quartz and the influence in dislocation flow - an overview. In: S. Karato and M. Toriumi (Editors), Rheology of Solids and of the Earth. Oxford University Press, London, pp. 107-142.

  17. Methodologies for Reservoir Characterization Using Fluid Inclusion Gas Chemistry

    SciTech Connect

    Dilley, Lorie M.

    2015-04-13

    The purpose of this project was to: 1) evaluate the relationship between geothermal fluid processes and the compositions of the fluid inclusion gases trapped in the reservoir rocks; and 2) develop methodologies for interpreting fluid inclusion gas data in terms of the chemical, thermal and hydrological properties of geothermal reservoirs. Phase 1 of this project was designed to conduct the following: 1) model the effects of boiling, condensation, conductive cooling and mixing on selected gaseous species; using fluid compositions obtained from geothermal wells, 2) evaluate, using quantitative analyses provided by New Mexico Tech (NMT), how these processes are recorded by fluid inclusions trapped in individual crystals; and 3) determine if the results obtained on individual crystals can be applied to the bulk fluid inclusion analyses determined by Fluid Inclusion Technology (FIT). Our initial studies however, suggested that numerical modeling of the data would be premature. We observed that the gas compositions, determined on bulk and individual samples were not the same as those discharged by the geothermal wells. Gases discharged from geothermal wells are CO2-rich and contain low concentrations of light gases (i.e. H2, He, N, Ar, CH4). In contrast many of our samples displayed enrichments in these light gases. Efforts were initiated to evaluate the reasons for the observed gas distributions. As a first step, we examined the potential importance of different reservoir processes using a variety of commonly employed gas ratios (e.g. Giggenbach plots). The second technical target was the development of interpretational methodologies. We have develop methodologies for the interpretation of fluid inclusion gas data, based on the results of Phase 1, geologic interpretation of fluid inclusion data, and integration of the data. These methodologies can be used in conjunction with the relevant geological and hydrological information on the system to

  18. Fluid inclusion analyses of detrital quartz grains - new Provenance Tool

    SciTech Connect

    Bloch, J.D.

    1985-02-01

    Preliminary analyses by microthermometry of fluid inclusions in detrital quartz of the Upper Cambrian Lamotte Sandstone revealed the occurrence of 2 distinct groups of aqueous fluid inclusions. Specific salinity signatures and homogenization temperatures may be used to distinguish specific granite types of the source rock terrain. The inclusions chosen for analysis occur in isolated clusters or are randomly distributed within a grain, commonly in association with mineral inclusions of zircon, sphene, rutile, and/or tourmaline. Secondary inclusions are present in the Lamotte but are not included in this study. The first group of inclusions is characterized by low salinities (< 1.0-8.0 wt.% eq. NaCl), the second by high salinities (12.1-29.6 wt. % eq. NaCl). Final melting temperatures as low as -30.6/sup 0/C indicate the presence of divalent ions in these inclusions. Both groups yield homogenization temperatures of between 150/sup 0/C and 220/sup 0/C. The low-salinity inclusions occur predominantly in subrounded to well-rounded sand less than 1.0 mm in size that is derived from a distal source. The brine inclusions occur exclusively in subangular to angular gravel 2.0-3.0 mm in size, implying a more proximal source area. A comparison of these inclusions with inclusions found in the granites of the apparent source terrain indicates that a medium-silica amphiboleorthoclase granite (Slabtown type) or a low-silica amphibole-plagioclase granite (Sivermines type) or both are the primary source rocks for this quartz. These granite types have limited areal distribution in the present day St. Francois mountains and the identification of these granite types as the source rock for the locally derived quartz has broad implications for reconstructing Cambrian depositional environments and paleostructure of the ancient St. Francois mountains.

  19. N 2-Ar-He compositions in fluid inclusions: Indicators of fluid source

    NASA Astrophysics Data System (ADS)

    Norman, David I.; Musgrave, John A.

    1994-02-01

    A quadrupole mass spectrometer was used to measure bulk samples of conservative gas species N 2, Ar, and He in fluid inclusions from a variety of hydrothermal systems. Analyses of these tracer elements help determine (1) if gases extracted by bulk inclusion analyses can provide accurate measurement of N 2-Ar-He in active and fossil geothermal systems, (2) if hydrothermal fluids associated with paleogeothermal systems in a continental setting follow N 2ArHe systematics similar to th the western Pacific Rim active geothermal systems, specifically New Zealand, and (3) whether different deposit types systematically vary with regard to N 2ArHe. The N 2ArHe ratios of fluid inclusion volatiles released from recently deposited minerals from the Valles system are similar to those of present day Valles thermal waters. Those inclusion samples from deep within the Valles system, below a regional aquitard, increase in N 2. Compositions for inclusions from the Questa and Copper Flat-porphyry deposits are N 2-rich, similar to those of arc-related volcanic gases, whereas those from Taylor Creek Sn deposit appear to be mixtures of magmatic and crustal components. N 2-Ar-He ratios of the Precambrian Tribag deposit suggest a basalt source, but significant levels of self-generated He from U and Th in the inclusion fluids are also possible. Inclusions from two epithermal deposits with low-salinity inclusions have N 2-Ar-He ratios trending towards air-saturated meteoric waters (ASW), and those inclusions with higher salinities indicate minor to no ASW component. The N 2-Ar-He ratios in Fresnillo and Cochiti inclusions, which have magmatic helium isotopic ratios, indicate additions of magmatic gases to meteoric fluids. Inclusions from sediment-hosted deposits that contain hydrocarbon-bearing brines are He-rich, as are meteoric waters with a long residence time in the crust. At relevant pressure-temperature-composition conditions, Henry's Law constants of N 2, Ar, and He

  20. Mantle-derived fluids in diamond micro-inclusions

    NASA Technical Reports Server (NTRS)

    Navon, O.; Hutcheon, I. D.; Rossman, G. R.; Wasserburg, G. J.

    1988-01-01

    Microinclusions in diamonds from Zaire and Botswana differ in composition from the more common large inclusions of the peridotitic or eclogitic assemblages. These sub-micrometer inclusions resemble potassic magmas in their composition, but are enriched in H2O, CO2(3-), and K2O and depleted in MgO. This composition represents a volatile-rich fluid or melt from the upper mantle, which was trapped in the diamonds as they grew.

  1. N-rich fluid inclusions in octahedrally-grown diamond

    NASA Astrophysics Data System (ADS)

    Smith, Evan M.; Kopylova, Maya G.; Frezzotti, Maria Luce; Afanasiev, Valentin P.

    2014-05-01

    Nitrogen is generally considered a trace component in the Earth's mantle. Mantle volatiles sampled from mid-ocean ridge basalts or preserved as fluid inclusions in xenoliths are dominated by CO2, with only traces of nitrogen. Here we describe CO2-N2 fluid inclusions with 40 mol% N2 and silicate melt inclusions with ∼0.1 wt% dissolved N2 in mantle-derived diamonds from 3 different cratons. The diamonds are octahedrally-grown, which is the most common growth habit and rarely reported to contain fluid inclusions. The inclusions have C/N ratios <1, more than two orders of magnitude below typical mantle values. We propose that nitrogen can become concentrated to high degrees by processes related to diamond growth. A growing diamond does not readily consume the nitrogen available, suggesting incompatible behaviour. Residual N2 from this process represents a concentrated nitrogen flux escaping the convecting mantle. Hidden nitrogen fluxes like this might be significant in counteracting the large apparent net influx by subduction. Based on nitrogen and carbon speciation in the inclusions, we propose that redox processes control the liberation of nitrogen from the convecting mantle, by the oxidation of NH+4 in silicates to mobile N2, concurrent with a parallel oxidation process releasing carbonate melt from the asthenosphere. Isotopic fractionation accompanying changes in nitrogen speciation could help account for the apparent isotopic mismatch between surficial and mantle nitrogen.

  2. Permian paleoclimate data from fluid inclusions in halite

    USGS Publications Warehouse

    Benison, K.C.; Goldstein, R.H.

    1999-01-01

    This study has yielded surface water paleotemperatures from primary fluid inclusions in mid Permian Nippewalla Group halite from western Kansas. A 'cooling nucleation' method is used to generate vapor bubbles in originally all-liquid primary inclusions. Then, surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid. Homogenization temperatures ranged from 21??C to 50??C and are consistent along individual fluid inclusion assemblages, indicating that the fluid inclusions have not been altered by thermal reequilibration. Homogenization temperatures show a range of up to 26??C from base to top of individual cloudy chevron growth bands. Petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data. We interpret these homogenization temperatures to represent shallow surface water paleotemperatures. The range in temperatures from base to top of single chevron bands may reflect daily temperatures variations. These Permian surface water temperatures fall within the same range as some modern evaporative surface waters, suggesting that this Permian environment may have been relatively similar to its modern counterparts. Shallow surface water temperatures in evaporative settings correspond closely to local air temperatures. Therefore, the Permian surface water temperatures determined in this study may be considered proxies for local Permian air temperatures.

  3. Mass spectrometric identification of boric acid in fluid inclusions in pegmatite minerals

    SciTech Connect

    Williams, A.E.; Taylor, M.C.

    1996-09-01

    Direct, on-line mass spectrometric analyses were performed on volatiles released from microscopic fluid inclusions in quartz, feldspar, and tourmaline from the miarolitic Belo Horizonte No. 1 pegmatite in the San Jacinto district, and Himalaya pegmatite dike system in the Mesa Grande district of southern California. These analyses are the first inclusion volatile studies to indicate the presence of significant and variable concentrations of B compounds in pegmatite formation fluids. Boron appears as boric acid B(OH){sub 3}, which is found at levels ranging from less than detection limit (<10{sup {minus}7} mole fraction) to as high as 10{sup {minus}4} mole fraction. High B concentrations are seen in inclusion fluids from miarolite filling quartz, cleavelandite variety albite feldspar, and schorl tourmaline from the Belo Horizonte No. 1, while negligible amounts appear in late-stage green/pink-zoned gem elbaite tourmalines from that mine. Fluid inclusions in quartz, as well as grey and pink tourmaline form the miarolites in the Himalaya mine, have undetectable levels of B compounds. In addition to confirming the presence of very high boric acid concentrations in some pegmatite forming solutions, observations of large variations in abundance may provide new constraints on fluid chemical evolution trends during the genesis of these regionally and paragenetically complex gem deposits. 38 refs., 6 figs., 1 tab.

  4. Identifying Fracture Types and Relative Ages Using Fluid Inclusion Stratigraphy

    SciTech Connect

    Dilley, Lorie M.; Norman, David; Owens, Lara

    2008-06-30

    Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Understanding the life cycle of a fracture in a geothermal system is fundamental to the development of techniques for creating fractures. Recognizing the stage of a fracture, whether it is currently open and transmitting fluids; if it recently has closed; or if it is an ancient fracture would assist in targeting areas for further fracture stimulation. Identifying dense fracture areas as well as large open fractures from small fracture systems will also assist in fracture stimulation selection. Geothermal systems are constantly generating fractures, and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. Fluid inclusions trapped in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. Our hypothesis is that fractures over their life cycle have different chemical signatures that we can see in fluid inclusion gas analysis and by using the new method of fluid inclusion stratigraphy (FIS) the different stages of fractures, along with an estimate of fracture size can be identified during the well drilling process. We have shown with this study that it is possible to identify fracture locations using FIS and that different fractures have different chemical signatures however that signature is somewhat dependent upon rock type. Open, active fractures correlate with increase concentrations of CO2, N2, Ar, and to a lesser extent H2O. These fractures would be targets for further enhancement. The usefulness of this method is that it is low cost alternative to current well logging techniques and can be done as a well is being drilled.

  5. Isotope geochemistry and fluid inclusion study of skarns from Vesuvius

    USGS Publications Warehouse

    Gilg, H.A.; Lima, A.; Somma, R.; Belkin, H.E.; de Vivo, B.; Ayuso, R.A.

    2001-01-01

    We present new mineral chemistry, fluid inclusion, stable carbon and oxygen, as well as Pb, Sr, and Nd isotope data of Ca-Mg-silicate-rich ejecta (skarns) and associated cognate and xenolithic nodules from the Mt. Somma-Vesuvius volcanic complex, Italy. The typically zoned skarn ejecta consist mainly of diopsidic and hedenbergitic, sometimes "fassaitic" clinopyroxene, Mg-rich and Ti-poor phlogopite, F-bearing vesuvianite, wollastonite, gehlenite, meionite, forsterite, clinohumite, anorthite and Mg-poor calcite with accessory apatite, spinell, magnetite, perovskite, baddeleyite, and various REE-, U-, Th-, Zr- and Ti-rich minerals. Four major types of fluid inclusions were observed in wollastonite, vesuvianite, gehlenite, clinopyroxene and calcite: a) primary silicate melt inclusions (THOM = 1000-1050??C), b) CO2 ?? H2S-rich fluid inclusions (THOM = 20-31.3??C into the vapor phase), c) multiphase aqueous brine inclusions (THOM = 720-820??C) with mainly sylvite and halite daughter minerals, and d) complex chloride-carbonate-sulfate-fluoride-silicate-bearing saline-melt inclusions (THOM = 870-890??C). The last inclusion type shows evidence for immiscibility between several fluids (silicate melt - aqueous chloride-rich liquid - carbonate/sulfate melt?) during heating and cooling below 870??C. There is no evidence for fluid circulation below 700??C and participation of externally derived meteoric fluids in skarn formation. Skarns have considerably variable 206Pb/204Pb (19.047-19.202), 207Pb/204Pb (15.655-15.670), and 208Pb/204Pb (38.915-39.069) and relatively low 143Nd/144Nd (0.51211-0.51244) ratios. The carbon and oxygen isotope compositions of skarn calcites (??13CV-PDB = -5.4 to -1.1???; ??18OV-SMOW = 11.7 to 16.4???) indicate formation from a 18O- and 13C-enriched fluid. The isotope composition of skarns and the presence of silicate melt inclusion-bearing wollastonite nodules suggests assimilation of carbonate wall rocks by the alkaline magma at moderate depths (< 5

  6. Mineral and Fluid Inclusions in the Diamonds from the Ural Placers, Russia

    NASA Astrophysics Data System (ADS)

    Sobolev, N. V.; Logvinova, A. M.; Fedorova, E. N.; Luk'yanova, L. I.; Wirth, R.; Tomilenko, A. A.; Bul'bak, T. A.; Reustsy, V. N.; Efimova, E. S.

    2015-12-01

    A study of compositions of mineral inclusions from representative collection (more than 150 samples) of diamonds from the placers of Ural Mountains was performed. Overwhelming majority of rounded octahedral and dodecahedral stones typical for placers contain eclogitic (E-type) mineral inclusions (up to 80%) represented by garnets with Mg# 40-75 and Ca# 10-56 including a unique high calcic "grospydite" composition, omphacitic pyroxenes containing up to 65% of jadeite as well as kyanite, coesite, sulphides and rutile. U/P type inclusions are represented by olivine, Cr-pyrope, chromediopside, enstatite and chromite typical for diamonds worldwide. One typical rounded dodecahedral diamond was found to contain abundant primary oriented submicrometer (<0.5 mm) octahedral fluid inclusions identified by TEM, caused a milky color of the whole diamond crystal. EEL spectrum of an inclusion has a peak at about 405 eV indicating the presence of nitrogen. Raman spectrum with a peak at 2348 cm-1 confirms the solid state of the nitrogen. This means that fossilized pressure inside fluid inclusions may be within the range of 4.0-4.5 GPa at room T. Volatile components of inclusions were analyzed by combined gas chromatography mass-spectrometry. They are represented by nitrogen (40%), water (26%), carbon dioxide (3,0%) and heavy hydrocarbons (CnH2n+2) which represent 30% rel. of all detected hydrocarbons. Equilibration PT conditions were estimated mainly from chemical composition of coexisting garnets and clinopyroxenes (35 pairs) as 950-1250oC at 5.0 GPa. However, the identification of unique fluid inclusions in one typical placer diamond allows to expand pressure limit at least up to 6.0 GPa. We conclude that Ural placer diamonds are of kimberlitic origin and are comparable in their high E-type/P-type inclusion ratios with those from north-eastern part of the Siberian Craton and in part with diamonds of Arkhangelsk kimberlite province.

  7. Trace Elemental Abundances in an Unusual Hibonite-Perovskite Refractory Inclusion from Allende

    NASA Astrophysics Data System (ADS)

    Mane, P.; Wadhwa, M.; Keller, L. P.

    2013-09-01

    This abstract discusses rare earth elemental abundances of an unusual hibonite- perovskite refractory inclusion (Named a s SHAL) from Allende CV3 meteorite and their implications about its formation history.

  8. Diagenetic palaeotemperatures from aqueous fluid inclusions: re- equilibration of inclusions in carbonate cements by burial heating.

    USGS Publications Warehouse

    Burruss, R.C.

    1987-01-01

    Calculations based on the observed behaviour of inclusions in fluorite under external confining P allows prediction of the T and depths of burial necessary to initiate re-equilibration of aqueous inclusions in the common size range 40-4 mu m. Heating of 20-60oC over the initial trapping T may cause errors of 10-20oC in the homogenization T. This suggests that re-equilibration may cause aqueous inclusions in carbonates to yield a poor record of their low-T history, but a useful record of the maximum T experienced by the host rock. Previous work suggests that inclusions containing petroleum fluids will be less susceptible to re-equilibration.This and the following six abstracts represent papers presented at a joint meeting of the Applied Mineralogy Group of the Mineralogical Society and the Petroleum Group of the Geological Society held in Newcastle upon Tyne in April 1986.-R.A.H.

  9. Analysis of fluid inclusion leachates from quartz by ion chromatography

    NASA Astrophysics Data System (ADS)

    Der Channer, D. M.; Spooner, E. T. C.

    1992-01-01

    20 chemical species have been detected and quantified in standard solutions using a Dionex 2000i-SP ion Chromatograph. These species are (minimum detection limits in ppb in injected sample follow each species; anions and cations listed in order of increasing retention time): F - (14), CH 3COO - (12), HCOO - (4), Cl - (6), NO -2 (9), Br -̊ (19), NO -3(16), HPO 2-4 (28), SO 2-4 (26), C 2O 2-4 oxalate (250), I - (20), Li + (0.5), Na +(0.7), NH +4 (0.6), K + (1.6), Rb + (3.5), Cs + (5.9), Mg 2+ (5), Ca 2+ (15) and Sr 2+ (100). A technique has been developed to clean fluid inclusion-bearing samples and obtain fluid inclusion leachates by hand crushing ~1-2 g samples under leaching solutions in an agate mortar and then separating the leachates by vacuum filtration. High-efficiency ion removal from the crushed sample is required since gas Chromatographic H 2O analyses of sample splits have been used to calculate species concentrations in fluid inclusions. Three separate crushes using different leaching solutions are required for a complete analysis. Cleaning procedures have been established for all components involved in the crush/leach procedure, and a system blank has been obtained by crush/leach analysis of heat-treated Brazilian quartz. The contact time between the leachate and the component (i.e., agate mortar) has been established as an important control on blank levels. The technique has been applied to three samples from the Tanco granitic pegmatite: the analyses show both a 'pegmatitic' and a possibly external fluid component. A combined, single sample, gas and ion Chromatographic procedure has been developed to link directly the fluid inclusion volatile and leachate data.

  10. Congenital myopathy with abundant ring fibres, rimmed vacuoles and inclusion body myositis-type inclusions.

    PubMed

    Fidziańska, A; Kamińska, A

    2003-02-01

    We report a 17-year-old girl with an unusual neuromuscular disorder characterised by slowly progressive proximal muscle weakness whose muscle biopsy showed multiple ring fibres and numerous rimmed vacuoles as well as intracytoplasmic and intranuclear inclusions of the inclusion body myositis-type. The clinical features of the presented case, manifested by the onset of the disease in early childhood, delayed motor development, short stature, lordosis and joint contractures were suggestive of congenital myopathy. The coexistence of ring fibres, rimmed vacuoles and inclusion-body myositis-type inclusions in a child with congenital myopathy has not been previously reported.

  11. Gas chromatographic analysis of volatiles in fluid and gas inclusions

    USGS Publications Warehouse

    Andrawes, F.; Holzer, G.; Roedder, E.; Gibson, E.K.; Oro, J.

    1984-01-01

    Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping. These inclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels. We present here some analyses of inclusions in a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography-mass spectrometry (GC-MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crusing surfaces, and is operated in a pure helium atmosphere at a controlled temperature. Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC-MS. This combination of procedures has been shown to provide geochemically useful information on the process involved in the history of the samples analyzed. ?? 1984.

  12. Mineralogical and Fluid Inclusion Studies on Seafloor Hydrothermal Vents at TA25 Caldera, Tonga Arc

    NASA Astrophysics Data System (ADS)

    Choi, S. K.; Pak, S. J.; Choi, S. H.; Lee, K. Y.; Kim, H. S.; Lee, I. K.

    2015-12-01

    The extensive hydrothermal vent field was discovered at TA25("V18s-HR" in the SO-167 cruise) caldera in the Tonga arc, southwest Pacific. The TA25 caldera is a submarine volcano of dacitic composition and hosts the NE- and NW-trending hydrothermal vent on the western caldera wall. These active hydrothermal crusters are mostly small (chimney: <0.5m in tall; sulfide mound: <3m in diameter) and immature, and emit the transparent fluids of which temperature range from 150℃ to 242℃ (average = 203℃). The hydrothermal sulfide ores, recovered by ROV and/or TV-grab, are mainly composed of sphalerite, pyrite, marcasite, galena, chalcopyrite, covellite, tennantite, enargite and sulfates such as barite, gypsum/anhydrite. It is observed that three distinct mineralogical zonation from exterior to interior of the chimneys: (1) barite-gypsum/anhydrite-pyrite-sphalerite; (2) sphalerite-pyrite-galena±chalcopyrite; (3) sphaleirte-pyrite-chalcopyrite-enargite-tennantite±galena±covellite. FeS content in sphalerite increases from chimney exterior to interior. Chalcopyrite is more abundant in the mound than in the chimney, implying fluid temperatures in mound are greater than in the chimney. The enargite assemblage (pyrite-chalcopyrite-enargite-tennantite) is indicative of high-sulfidation epithermal deposits. Fluid inclusions on barite crystals from mound samples show mono-type inclusion (two-phase liquid-rich inclusions) which is less than 20㎛ in diameter. Homogenization temperatures and salinities from fluid inclusion study range from 148℃ to 341℃ (average = 213℃) and 0.4 to 3.6 equiv. wt.% NaCl, respectively. The main mineralization temperature in mound might be greater than 200℃ since barite on fluid inclusion is early stage mineral.

  13. Gas chromatographic analysis of volatiles in fluid and gas inclusions.

    PubMed

    Andrawes, F; Holzer, G; Roedder, E; Gibson, E K; Oro, J

    1984-01-01

    Most geological samples and some synthetic materials contain fluid inclusions. These inclusions preserve for us tiny samples of the liquid and/or the gas phase that was present during formation, although in some cases they may have undergone significant changes from the original material. Studies of the current composition of the inclusions provide data on both the original composition and the change since trapping. These conclusions are seldom larger than 1 millimeter in diameter. The composition varies from a single major compound (e.g., water) in a single phase to a very complex mixture in one or more phases. The concentration of some of the compounds present may be at trace levels. We present here some analyses of inclusion on a variety of geological samples, including diamonds. We used a sample crusher and a gas chromatography-mass spectrometry (GC-MS) system to analyze for organic and inorganic volatiles present as major to trace constituents in inclusions. The crusher is a hardened stainless-steel piston cylinder apparatus with tungsten carbide crushing surfaces, and is operated in a pure helium atmosphere at a controlled temperature. Samples ranging from 1 mg to 1 g were crushed and the released volatiles were analyzed using multi-chromatographic columns and detectors, including the sensitive helium ionization detector. Identification of the GC peaks was carried out by GC-MS. This combination of procedures has been shown to provide geochemically useful information on the processes involved in the history of the samples analyzed. PMID:11541990

  14. Fluid inclusion and H-O isotope evidence for immiscibility during mineralization of the Yinan Au-Cu-Fe deposit, Shandong, China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Gu, X. X.; Liu, L.; Dong, S. Y.; Li, K.; Li, B. H.; Lv, P. R.

    2011-07-01

    The fluid inclusion and H-O isotope studies have provided the evidences for the source of ore-forming fluids, and helped to recognize two types of immiscibility and their relationships with mineralization. Hydrogen and oxygen isotopic geochemistry shows that the earlier ore-forming fluids during the anhydrous skarn stage (I) and the hydrous skarn-magnetite stage (II) were mainly derived from magmatic water, while the later fluids during the quartz-sulfide stage (III) and the carbonate stage (IV) were mainly from magmatic water mixed with small amounts of meteoric water. Various types of fluid inclusions, including abundant vapor- or liquid-rich two-phase aqueous inclusions, daughter minerals-bearing multiphase inclusions, CO 2-H 2O inclusions, and less abundant liquid inclusions, vapor inclusions and melt inclusions, are present in hydrothermal minerals of different stages. The liquid-vapor fluid inclusions are mainly composed of H 2O, with significant amounts of CO 2 and a small amount of CH 4. In the opaque-bearing fluid inclusions, the hematite and fahlore (tetrahedrite) were identified. The homogenization temperature of the aqueous fluid inclusions decreases from Stage I (520-410 °C), through Stage II (430-340 °C) and III (250-190 °C), to Stage IV (190-130 °C). The coexistence of melt inclusions with simultaneously trapped vapor- or liquid-rich two-phase aqueous inclusions and daughter minerals-bearing multiphase inclusions in garnet, diopside and epidote of Stages I and II suggests an immiscibility between silicate melt and hydrothermal fluid. It is an effective mechanism on scavenging and transporting ore-forming components from magmas. The aqueous fluid inclusions with various vapor/liquid ratios (from <10% to >65%) commonly coexist with simultaneously trapped liquid inclusions, vapor inclusions, daughter minerals-bearing multiphase inclusions and CO 2-H 2O inclusions in the quartz of Stage III, and the different kinds of the fluid inclusions have

  15. Inclusions of Hydrocarbon Fluids in Diamonds From Wafangdian, Liaoning, China

    NASA Astrophysics Data System (ADS)

    Leung, I. S.; Tsao, C.

    2015-12-01

    We studied a large number of industrial-grade diamonds from Pipe 50 of Liaoning, China. These diamonds are not suitable for polishing into gems or making cutting tools. They are usually crushed to form abrasives, without much scientific scrutiny. We report here fluid inclusions in dozens of diamonds. The first type of fluids occur in the outer rim of diamonds, just below the surface, while their interior is free of visible fluids. Under UV radiation, when a non-fluorescent diamond appeared dim, bubbles of included fluids became visible as yellow and blue spherules. Such diamonds are sometimes encrusted with euhedral micro-diamonds resembling those on thin films grown by CVD. The second type of fluid-rich diamonds display iridescence of pink, blue, green and yellow colors. They show lamellar, filamentous, or tubular structures, some of the tubes are filled with granules, probably grown from fluids in the tubes. An FT-IR investigation of both types yielded similar results. Apart from absorption due to intrinsic diamond lattice vibrations, we found an outstanding group of bands just below wavenumber 3000. This indicates the presence of a saturated aliphatic hydrocarbons of long chain length. Our results seem to implicate that hydrocarbons might be an important component in Earth's mantle, which might even have provided carbon from which diamonds crystllized.

  16. First results on stable isotopes in fluid inclusions in cryogenic carbonates from Ural Mountains (Russia)

    NASA Astrophysics Data System (ADS)

    Dublyansky, Yuri; Luetscher, Mark; Spötl, Christoph; Töchterle, Paul; Kadebskaya, Olga

    2015-04-01

    Cryogenic cave carbonates (CCC) were found in a number of caves in the Ural. In contrast to the CCC previously reported from Central Europe, the Uralian CCC have larger sizes (up to 4-5 cm), which allows for more detailed petrographic and geochemical studies. CCCs from Uralian caves commonly show spherulitic shapes due to crystal splitting, supporting the model of calcite precipitating in a freezing water pond. δ18O values of studied CCCs are lower by 1 to 14 o compared to noncryogenic speleothems of Pleistocene and Holocene age from the same caves. δ18O and δ13C values are inversely correlated and typically show a fractionation between the core and the rim of individual samples. These trends are similar to those reported for CCCs from European caves (Žák et al., 2004). Petrographic observations performed on doubly polished, 100-150 micron-thick sections revealed abundant fluid inclusions, trapped between fibres of the spherulites. Petrographic relationships suggest that these inclusions are primary. The isotopic composition of water trapped in fluid inclusions in CCCs from two caves was analyzed following mechanical crushing at 120 °C, cryo-trapping of released water, pyrolysis on glassy carbon at 1400 °C (TC/EA device; Thermo), and analysis of the evolved gases on an isotope ratio mass spectrometer (Delta V Advantage; Thermo Fisher). The lack of peaks on the m/z 2 trace during the heating of the loaded crushing cell attests for a good sealing of the fluid inclusions. The measured δD values range between -136 o and -145 o VSMOW. The values measured in CCCs are more negative than the typical values of fluid inclusion water measured in the Holocene stalagmites from central Ural (-99 to -108 ). This shift toward more negative values is attributed to the isotopic fractionation between ice and water during the freezing. Reference: Žák et al., 2004, Chemical Geology, 2006, 119-136.

  17. Constraints from fluid inclusions in mantle minerals on the composition of subduction-zone fluids

    NASA Astrophysics Data System (ADS)

    Schiano, P.; Provost, A.; Cluzel, N.

    2013-12-01

    Slab-derived fluids are thought to enrich the mantle wedge in water and trace elements, and this metasomatized mantle region becomes the source of island arc basalts. Much of the evidence for this model has been derived indirectly through the study of the composition of the end-products, the lavas, and there have only been a few direct studies of the metasomatism of the mantle rocks from these regions. Therefore important aspects of the model have remained somewhat hypothetical. In particular, there are different viewpoints on the nature of subduction fluids, their trace element compositions and their pathways in the slab and overlying mantle. The whole debate is also hampered by the limited memory that high-pressure metamorphic rocks preserve of their subduction history, due to retrograde overprinting during exhumation, and by uncertainties in reproducing the conditions of subduction during experiments. Here we identify trapped pristine samples of the fluid phase percolating through the mantle wedge beneath island arcs, by examining fluid inclusions trapped within spinel-harzburgite xenoliths in an arc-front volcano (Batan island, Luzon arc). The xenoliths correspond to previously metasomatized mantle fragments incorporated in the lavas during ascent. Cl-bearing H2O-rich fluid inclusions occur within both primary (ol, opx) and late metasomatic minerals (e.g., cpx, phlogopite, amphibole). They were formed by the addition of aqueous fluids or by separation of aqueous fluids from H2O-saturated melt inclusions, as suggested by the occurrence of composite inclusions consisting of silicate glass and H2O (liq+vap). The associated silicate melt inclusions were previously shown to display silica-rich compositions that are consistent with slab-derived melts [1] or melts of metasomatized mantle peridotites [2]. In situ Raman spectroscopy reveals that at room temperature, the fluid inclusions are composed mainly of H2O, H2S and HS- and contain also sulphur (S6) and Mg

  18. Fluid inclusions associated with exsolution quartz needles in omphacite of UHP eclogites from the main hole of Chinese continental scientific drilling project

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Shen, K.; Liou, J.; Xu, Z.

    2005-12-01

    Abundant primary fluid inclusions are recognized in omphacite of ultrahigh-pressure (UHP) eclogites from the main hole of the Chinese Continental Scientific Drilling (CCSD), located at the southern Sulu orogenic belt. The eclogites consist of garnet, omphacite, coesite and rutile. Mineral and fluid inclusions are distributed alternatively and parallel to each other. The solid inclusions occur as needles with a length of 10~100 m and a width of 1~10 m whereas the fluid inclusions occur as tubes with the size varying from less then 3~5 m to greater then 50 m. The mineral inclusions were identified as quartz. Most fluid inclusions contain a gas bubble, a liquid phase and one to several solids. The liquid and gas phases are determined as H2O. The solid phases include halite, quartz and calcite, as well as opaque and unknown minerals. Some small thin-tubed fluid inclusions contain little or no solid and even without gas bubble; they contain dominantly water. The inclusion fluid was estimated to contain components in the system of NaCl-CaCl2-CO2-H2O-SiO2 with possibly trace Fe and Mg. We suggest that these fluid inclusions were conventional primary ones, and trapped during omphacite crystallization; upon decompression they acted as nucleation site for the crystallographically controlled precipitation of quartz from the omphacite matrix. Therefore the omphacite is considered to be one of the major fluid carriers during subduction of continental crust to mantle depths.

  19. Comparative Fluid Inclusion Chemistry of Miarolitic Pegmatites from San Diego County, California, USA

    NASA Astrophysics Data System (ADS)

    Nymberg, D.; Sirbescu, M. L. C.

    2014-12-01

    Miarolitic Li-Cs-Ta pegmatites are an important source of gemstones such as tourmaline var. elbaite and spodumene var. kunzite, but the distribution of gem-bearing pegmatites within a pegmatite field is not understood. This microthermometry, LA-ICP-MS, Raman spectroscopy, and crush-leach study of fluid inclusions in pegmatite quartz aims to discern the chemical variations of late-stage pegmatite fluids in relation to gem mineralization. We studied five mines from three San Diego Co. districts: Chihuahua Valley (C), Jacumba (J), and Pala (P). The ~100 Ma old, 1-10 m thick, subparallel magma sheets intruded plutons of the Peninsular Ranges Batholith or prebatholitic metasediments at an estimated pressure of 200-300 MPa. The pegmatites formed sequentially, from outer zones with comb, layered, and graphic quartz-feldspar textures at the magmatic stage to massive cores and miarolitic pockets at a late, fluid-saturated stage. Pocket quartz was analyzed from pegmatites of variable host rock, magmatic mineral assemblages, and known gem production. The inclusions contained two-phase aqueous fluids and no CO2 or other gases. Fluid salinity ranged from 0.5 to 8.6 wt.% NaCl eq. and correlated positively with inclusion homogenization temperature. Isochoric T at 250 MPa calculated for primary and pseudosecondary inclusions in pocket quartz ranged from 280 to 500 °C in district P, 310-420°C in J, and 230-290°C in C. We attribute the higher T of pocket formation in districts P and J to higher surrounding T at emplacement caused by proximity to other dikes. This preliminary study suggests that gem elbaite and/or kunzite occurrence correlates to Li and B contents in the pocket fluid, which, in turn, are a function of consumption by early, magmatic minerals. The P district has a simple leucogranite mineralogy at the magmatic stage; has as much as 5760 ppm B and 4950 ppm Li in the pocket fluid; and produced both elbaite and kunzite. The J district has abundant magmatic tourmaline

  20. Fluid inclusions in Scourian granulites from the Lewisian complex of NW Scotland: evidence for CO 2-rich fluid in Late Archaean high-grade metamorphism

    NASA Astrophysics Data System (ADS)

    Andersen, T.; Whitehouse, M. J.; Burke, E. A. J.

    1997-07-01

    In this paper the first fluid-inclusion data are presented from Late Archaean Scourian granulites of the Lewisian complex of mainland northwest Scotland. Pure CO 2 or CO 2-dominated fluid inclusions are moderately abundant in pristine granulites. These inclusions show homogenization temperatures ranging from - 54 to + 10 °C with a very prominent histogram peak at - 16 to - 32 °C. Isochores corresponding to this main histogram peak agree with P-T estimates for granulite-facies recrystallization during the Badcallian (750-800 °C, 7-8 kbar) as well as with Inverian P-T conditions (550-600 °C, 5 kbar). The maximum densities encountered could correspond to fluids trapped during an early, higher P-T phase of the Badcallian metamorphism (900-1000 °C, 11-12 kbar). Homogenization temperatures substantially higher than the main histogram peak may represent Laxfordian reworking (≤ 500 °C, < 4 kbar). In the pristine granulites, aqueous fluid inclusions are of very subordinate importance and occur only along late secondary healed fractures. In rocks which have been retrograded to amphibolite facies from Inverian and/or Laxfordian shear zones, CO 2 inclusions are conspicuously absent; only secondary aqueous inclusions are present, presumably related to post-granulite hydration processes. These data illustrate the importance of CO 2-rich fluids for the petrogenesis of Late Archaean granulites, and demonstrate that early fluid inclusions may survive subsequent metamorphic processes as long as no new fluid is introduced into the system.

  1. The composition of fluids generated during deep continental subduction estimated from fluid inclusions in UHP rocks

    NASA Astrophysics Data System (ADS)

    Ferrando, S.; Frezzotti, M.; Compagnoni, R.

    2009-12-01

    Composition and provenance of slab-derived hydrous fluids and melts represent a key parameter in understanding the geochemical variations of subduction-related magmas. Chemical and physical characteristics of the slab components may be strongly reliant upon both the thermal structure of the mantle wedge, and the nature of the subducted lithosphere. While fluids are well known to play a key role in element recycling during subduction of oceanic crust, it is less clear how dehydration and/or melting occur during subduction of continental crust. A direct approach to get information on the nature of fluids is provided by fluid inclusion analysis. Two examples of peak fluid inclusions in UHP metamorphic rocks from the Su-Lu Terrane (China) and the Dora-Maira Massif (Alps) are discussed. In the Su-Lu terrane, primary multiphase solid (MS) inclusions within UHP quartzites represent fluids internally generated through dehydration reactions at pressure above 3.5 GPa. Inclusions contain paragonite, muscovite, sulfates, carbonates, phosphates, and oxides. Calculated compositions indicate aqueous fluids (H2O = 25 - 50 wt %) containing tens of wt % of Si, Al, and alkalies. Trace element patterns show enrichments in large-ion lithophile elements (LILE; K, Sr, Rb, Cs, Ba, Pb, U) and light rare earth elements (LREE). In the Dora-Maira whiteschists, MS inclusions formed at 730°C and ≤ 4GPa have rather complex compositions and consist of Mg-chlorite, Na-phlogopite, Cl-rich apatite, Zn-rich pyrite, and chlorides, with subordinate talc and magnesite. Although water is absent, IR-synchrotron-radiation mapping revealed significant H+ diffusion from MS inclusions to host garnet. Peak aqueous solutions are Si, Al, and Na-rich, and contain significant amounts of Mg, Ca, P, S, and LILE, supporting an open system fluid generation with significant contribution from external brines derived from dehydration of oceanic lithosphere during subduction. Although the studied rocks have been

  2. Experimental Simulation of Shock Reequilibration of Fluid Inclusions During Meteorite Impact

    NASA Technical Reports Server (NTRS)

    Madden, M. E. Elwood; Hoerz, R. J.; Bodnar, R. J.

    2003-01-01

    Fluid inclusions are microscopic volumes of fluid trapped within minerals as they precipitate. Fluid inclusions are common in terrestrial minerals formed under a wide array of geological settings from surface evaporite deposits to kimberlite pipes. While fluid inclusions in terrestrial rocks are the rule rather than the exception, only few fluid inclusion-bearing meteorites have been documented. The rarity of fluid inclusions in meteoritic material may be explained in two ways. First, it may reflect the absence of fluids (water?) on meteorite parent bodies. Alternatively, fluids may have been present when the rock formed, but any fluid inclusions originally trapped on the parent body were destroyed by the extreme P-T conditions meteorites often experience during impact events. Distinguishing between these two possibilities can provide significant constraints on the likelihood of life on the parent body. Just as textures, structures, and compositions of mineral phases can be significantly altered by shock metamorphism upon hypervelocity impact, fluid inclusions contained within component minerals may be altered or destroyed due to the high pressures, temperatures, and strain rates associated with impact events. Reequilibration may occur when external pressure-temperature conditions differ significantly from internal fluid isochoric conditions, and result in changes in fluid inclusion properties and/or textures. Shock metamorphism and fluid inclusion reequilibration can affect both the impacted target material and the meteoritic projectile. By examining the effects of shock deformation on fluid inclusion properties and textures we may be able to better constrain the pressure-temperature path experienced by shocked materials and also gain a clearer understanding of why fluid inclusions are rarely found in meteoritic samples.

  3. Fluid inclusions in apatite from Jacupiranga calcite carbonatites: Evidence for a fluid-stratified carbonatite magma chamber

    NASA Astrophysics Data System (ADS)

    Costanzo, Alessandra; Moore, Kathryn Ruth; Wall, Frances; Feely, Martin

    2006-10-01

    Carbonatites of the Jacupiranga alkaline-carbonatite complex in São Paulo State, Brazil, were used to investigate mineral-fluid interaction in a carbonatite magma chamber because apatite showed a marked discontinuity between primary fluid inclusion-rich cores and fluid inclusion-poor rims. Sylvite and burbankite, apatite, pyrite, chalcopyrite and ilmenite are the common phases occurring as trapped solids within primary fluid inclusions and reflect the general assemblage of the carbonatite. The apatite cores had higher Sr and REE concentrations than apatite rims, due to the presence of fluid inclusions into which these elements partitioned. A positive cerium anomaly was observed in both the core and rim of apatite crystals because oxidised Ce 4+ partitioned into the magma. The combined evidence from apatite chemistry, fluid inclusion distribution and fluid composition was used to test the hypotheses that the limit of fluid inclusion occurrence within apatite crystals arises from: (1) generation of a separate fluid phase; (2) utilization of all available fluid during the first stage of crystallization; (3) removal of crystals from fluid-rich magma to fluid-poor magma; (4) an increase in the growth rate of apatite; or (5) escape of the fluids from the rim of the apatite after crystallization. The findings are consistent with fractionation and crystal settling of a carbonatite assemblage in a fluid-stratified magma chamber. Secondary fluid inclusions were trapped during a hydrothermal event that precipitated an assemblage of anhedral crystals: strontianite, carbocernaite, barytocalcite, barite and norsethite, pyrophanite, magnesian siderite and baddeleyite, ancylite-(Ce), monazite-(Ce) and allanite. The Sr- and REE-rich nature of the secondary assemblage, and lack of a positive cerium anomaly indicate that hydrothermal fluids have a similar source to the primary magma and are related to a later carbonatite intrusion.

  4. P-T condition fo deformation from fluid inclusions in mylonites

    NASA Technical Reports Server (NTRS)

    Mclellan, Eileen

    1990-01-01

    Structural petrology of fluid inclusions in deformed rocks can be used to identify inclusions entrapped during various stages of deformation. Standard thermobarometry on these inclusions can then provide estimates of the P-T (pressure-temperature) conditions of deformation. The application of this technique is illustrated using fluid inclusions in mylonites from the Quetico Fault Zone, Canada. The inferred P-T conditions fall with the P-T field of mylonitisation derived from isotopic, microstructural and phase equilibrium studies.

  5. CO2-rich fluid inclusions in greenschists, migmatites, granulites, and hydrated granulites

    NASA Technical Reports Server (NTRS)

    Hollister, L. S.

    1988-01-01

    Data was discussed from several different terrains in which CO2-rich fluid inclusions occur despite parageneses that predict the presence of H2O-rich fluids. CO2-rich fluid inclusions, some having densities appropriate for peak-metamorphic conditions, were found in greenschists, amphibolites, migmatites, and hydrated granulites. The author suggested that there may be a common process that leads to CO2-rich secondary inclusions in metamorphic rocks.

  6. Fluid/melt inclusions in alluvial Northeast Siberian diamonds: new approach on diamond formation.

    NASA Astrophysics Data System (ADS)

    Logvinova, Alla M.; Wirth, Richard; Sobolev, Nikolai V.

    2010-05-01

    The origin of alluvial Northeast Siberian diamonds is still a subject of controversy. Fluid/melt inclusions in diamonds are the deepest available samples of mantle fluids and provide the unique information on the medium in which diamonds have grown. These inclusions carry high-density fluids (HDFs), the compositional variability is in the range of hydrous-silicic, carbonatitic (high-Mg and low-Mg) and saline end-members. Previous studies of the bulk composition and internal morphology of microinclusions in alluvial Northeast Siberian diamonds suggested that they contain fluids, but distribution and structure of their constitutional phases could not be determined. We investigated two populations of diamonds from Northeast Siberian Platform placers (Ebelyakh area) using TEM, FTIR, EPMA methods: (I) rounded single-crystals (dodecahedrons, octahedrons and irregular stones with a black central zone rich in microinclusions. Some of them frequently exhibit growth twinning; (II) rounded dark crystals, related to variety V according to the classification by Orlov (1977). This group of stones has their own typical features: dark color due to abundant black microinclusions and high dislocation density; mosaic-block internal structure; very light carbon isotopic composition; the high degree of nitrogen aggregation and nearly total absence of mineral inclusions. Diamonds of the first population are characterized by two types of fluid/melt nanoinclusions:1) multi-phase high- Mg assemblages, which include solid phases (magnesite, dolomite, clinohumite, Fe-spinel, graphite) and fluid bubbles; 2) oriented sulfide melt nanoinclusions in association with halides (KCl, NaCl), high-Si mica and fluid bubbles. All of them ranging between 5 and 200 nm in diameter are reflecting the diamond habit. Sulfides are homogeneous in composition. The Ni/(Ni+Fe) ratio of the inclusions is 0.037±0.04. Still closed fluid bubbles were identified in TEM studies as changing absorption contrast due to

  7. Oscillations in Phanerozoic seawater chemistry: evidence from fluid inclusions.

    PubMed

    Lowenstein, T K; Timofeeff, M N; Brennan, S T; Hardie, L A; Demicco, R V

    2001-11-01

    Systematic changes in the chemistry of evaporated seawater contained in primary fluid inclusions in marine halites indicate that seawater chemistry has fluctuated during the Phanerozoic. The fluctuations are in phase with oscillations in seafloor spreading rates, volcanism, global sea level, and the primary mineralogies of marine limestones and evaporites. The data suggest that seawater had high Mg2+/Ca2+ ratios (>2.5) and relatively high Na+ concentrations during the Late Precambrian [544 to 543 million years ago (Ma)], Permian (258 to 251 Ma), and Tertiary through the present (40 to 0 Ma), when aragonite and MgSO4 salts were the dominant marine precipitates. Conversely, seawater had low Mg2+/Ca2+ ratios (<2.3) and relatively low Na+ concentrations during the Cambrian (540 to 520 Ma), Silurian (440 to 418 Ma), and Cretaceous (124 to 94 Ma), when calcite was the dominant nonskeletal carbonate and K-, Mg-, and Ca-bearing chloride salts, were the only potash evaporites.

  8. Trace Element Abundances in an Unusual Hibonite-Perovskite Refractory Inclusion from Allende

    NASA Technical Reports Server (NTRS)

    Mane, Prajkta; Wadhwa, M.; Keller, L. P.

    2013-01-01

    Calcium-aluminum-rich refractory inclusions (CAIs) are thought to be the first-formed solids in the Solar protoplanetary disk and can provide information about the earliest Solar System processes (e.g., [1]). A hibonite-perovskitebearing CAI from the Allende CV3 chondrite (SHAL, [2]) contains a single of 500 micrometers hibonite grain and coarse-grained perovskite. The mineralogy and oxygen isotopic composition of this CAI shows similarities with FUN inclusions, especially HAL [2]. Here we present trace element abundances in SHAL.

  9. The interaction of migrating grain boundaries with fluid inclusions in rock analogues: the effect of wetting angle and fluid inclusion velocity

    NASA Astrophysics Data System (ADS)

    Schmatz, Joyce; Schenk, Oliver; Urai, Janos L.

    2011-07-01

    The distribution of fluids in grain boundaries, fluid inclusion morphology and kinetics have important effects on the evolution of microstructure and transport properties and should be understood for correct interpretations for studies of thermobarometry and paleorheology. We compare results of in situ annealing experiments on rock analogues in the presence of different pore fluids in transmitted light: bischofite with saturated brine, camphor with ethanol, and camphor with ethylene glycol. The solid-liquid systems vary in terms of wettability and solubility, while homologous temperatures, strain rates, annealing times, and the initial textures are similar. In agreement with earlier work and theory, we observe different types of grain boundary-fluid inclusion interaction at sufficiently low grain boundary velocity such as drag and drop, necking, and the break up into arrays of smaller inclusions. In all three systems the maximum possible velocity of a fluid inclusion being dragged by a moving grain boundary is dependent on the fluid inclusion size. We interpret this to reflect the fluid inclusion mobility, and compare the trend with theoretical models which suggest that for all three systems the rate-limiting process is bulk diffusion and not surface diffusion or solution-precipitation.

  10. In-situ investigations of grain boundary-fluid inclusion interaction in recrystallizing rock analogues

    NASA Astrophysics Data System (ADS)

    Schmatz, J.; Schenk, O.; Urai, J. L.

    2009-12-01

    Investigating the mobility of fluid inclusions and fluid-rock interaction helps characterizing the effect of pore fluid on i) mechanical properties of rocks and ii) transport properties of fluid through rock volume. We present results from deformation and annealing experiments in transmitted light using rock analogues containing a liquid phase. The deformation rig is a high-pressure (up to 30 MPa), high-temperature (up to 200°C) see-through vessel with a controlled pore fluid pressure system. Samples were made of bischofite-brine, camphor-ethanol, and camphor-ethylene mixtures with the solid being polycrystalline with grain sizes ranging from 200 to 600 µm and with varying solubility in the liquid phase. In all systems the liquid phase is predominantly observed in isolated fluid inclusions and fluid pockets along grain boundaries with sizes ranging from 1 to 50 µm. Results show the in-situ pore fluid morphology during grain boundary migration recrystallization with preferential leakage of fluid inclusions along grain boundaries. For grain boundary migration rates ranging from 10-10 to 10-6 ms-1 we observed Zener pinning, drag and drop of fluid inclusions by migrating grain boundaries, but also passage of grain boundaries over fluid inclusions without any noticeable interaction, all being dependent on fluid inclusion size and solubility. Systematic measurements allowed tracing the maximum velocity of dragged fluid inclusions as well as the drag-limiting grain boundary velocity. The effects of these limiting conditions on recrystallized texture and on mobility of isolated fluid inclusions are subject to numerical simulations using the microstructural modeling platform ELLE. Image sequence showing fluid inclusion detaching from migrating grain boundary. Systematic measurements on pore shape evolution through time provide us the base for an empirical solution for pore drag and drop. The dragging time can be described as a function of grain boundary velocity, pore

  11. Using Fluid Inclusions to Bring Phase Diagrams to Life in a Guided Inquiry Instructional Setting

    NASA Astrophysics Data System (ADS)

    Farver, J. R.; Onasch, C.

    2011-12-01

    A fundamental concept in mineralogy, petrology, and geochemistry is the generation and interpretation of phase diagrams for various systems. We have developed an exercise to strengthen student's familiarity with and confidence in employing phase diagrams by using fluid inclusions. The activity follows the 5Es (Engagement, Exploration, Explanation, Extension, Evaluation) guided inquiry instructional model in order to best facilitate student learning. The exercise follows an activity adapted from Brady (1992) wherein students collect data to generate the phase diagram for the Ice-Water-NaCl system. The engagement activity involves using a USGS-type fluid inclusion heating-cooling stage with a camera and projection system. We typically employ either a doubly-polished quartz sample or a cleaved section of fluorite and select a typical two phase (L + V) aqueous inclusion. Students first observe the inclusion at room temperature and pressure and are asked to predict what would happen if the sample is heated. Students then watch as the sample is heated to its homogenization temperature (Th) and are asked to explain what they see. The sample is then cooled until completely frozen and then slowly warmed until the first ice melting (at the eutectic, Te) and then until all ice melts (Tm). Again, students are asked to explain what they see and, if necessary, they are guided to remember the earlier phase diagram activity. The process is then repeated while students follow along the appropriate phase diagrams. In this fashion, students literally see the changes in phases present and their relative abundances as they move through the phase diagram. The engagement activity generates student interest in the exercise to insure minds-on as well as hands-on exploration. The exploration activities involve students observing and describing a wide range of fluid inclusion types (e.g., CO2, daughter crystals, multiple inclusion trails, etc) and hands-on collection of Th and Tm data for a

  12. Fluid inclusion studies of chemosynthetic carbonates: strategy for seeking life on Mars.

    PubMed

    Parnell, John; Mazzini, Adriano; Honghan, Chen

    2002-01-01

    Fluid inclusions in minerals hold the potential to provide important data on the chemistry of the ambient fluids during mineral precipitation. Especially interesting to astrobiologists are inclusions in low-temperature minerals that may have been precipitated in the presence of microorganisms. We demonstrate that it is possible to obtain data from inclusions in chemosynthetic carbonates that precipitated by the oxidation of organic carbon around methane-bearing seepages. Chemosynthetic carbonates have been identified as a target rock for astrobiological exploration. Other surficial rock types identified as targets for astrobiological exploration include hydrothermal deposits, speleothems, stromatolites, tufas, and evaporites, each of which can contain fluid inclusions. Fracture systems below impact craters would also contain precipitates of minerals with fluid inclusions. As fluid inclusions are sealed microchambers, they preserve fluids in regions where water is now absent, such as regions of the martian surface. Although most inclusions are < 5 microns, the possibility to obtain data from the fluids, including biosignatures and physical remains of life, underscores the advantages of technological advances in the study of fluid inclusions. The crushing of bulk samples could release inclusion waters for analysis, which could be undertaken in situ on Mars. PMID:12449854

  13. Fluid inclusion studies of chemosynthetic carbonates: strategy for seeking life on Mars.

    PubMed

    Parnell, John; Mazzini, Adriano; Honghan, Chen

    2002-01-01

    Fluid inclusions in minerals hold the potential to provide important data on the chemistry of the ambient fluids during mineral precipitation. Especially interesting to astrobiologists are inclusions in low-temperature minerals that may have been precipitated in the presence of microorganisms. We demonstrate that it is possible to obtain data from inclusions in chemosynthetic carbonates that precipitated by the oxidation of organic carbon around methane-bearing seepages. Chemosynthetic carbonates have been identified as a target rock for astrobiological exploration. Other surficial rock types identified as targets for astrobiological exploration include hydrothermal deposits, speleothems, stromatolites, tufas, and evaporites, each of which can contain fluid inclusions. Fracture systems below impact craters would also contain precipitates of minerals with fluid inclusions. As fluid inclusions are sealed microchambers, they preserve fluids in regions where water is now absent, such as regions of the martian surface. Although most inclusions are < 5 microns, the possibility to obtain data from the fluids, including biosignatures and physical remains of life, underscores the advantages of technological advances in the study of fluid inclusions. The crushing of bulk samples could release inclusion waters for analysis, which could be undertaken in situ on Mars.

  14. Neutron activation analysis of fluid inclusions for copper, manganese, and zinc

    USGS Publications Warehouse

    Czamanske, G.K.; Roedder, E.; Burns, F.C.

    1963-01-01

    Microgram quantities of copper, manganese, and zinc, corresponding to concentrations greater than 100 parts per million, were found in milligram quantities of primary inclusion fluid extracted from samples of quartz and fluorite from two types of ore deposits. The results indicate that neutron activation is a useful analytical method for studying the content of heavy metal in fluid inclusions.

  15. Hydrothermal mineralogy and fluid inclusions chemistry to understand the roots of active geothermal systems

    NASA Astrophysics Data System (ADS)

    Chambefort, I. S.; Dilles, J. H.; Heinrich, C.

    2013-12-01

    An integrated study to link magmatic textures, magmatic mineral compositions, hydrothermal alteration zoning, hydrothermal mineral chemistry, and fluid inclusion compositions has been undertaken to link an intrusive complex and its degassing alteration halo with their surface equivalent in an active geothermal system. Ngatamariki geothermal system, New Zealand, presents a unique feature in the Taupo Volcanic Zone (TVZ). Drilling intercepted an intrusive complex with a high temperature alteration halo similarly to what is observed in magmatic-derived ore deposits. Thus it presents the perfect opportunity to study the magmatic-hydrothermal transition of the TVZ by characterizing the nature of the deep magmatic fluids link to the heat source of the world known geothermal fields. The record of magmatic-hydrothermal fluid-rock interactions preserved at Ngatamariki may be analogous of processes presently occurring at depth beneath TVZ geothermal systems. The intrusive complex consists of over 5 km3 of tonalite, diorite, basalt and aplitic dykes. Evidence of undercooling subsolidus magmatic textures such as myrmekite and skeletal overgrowth are commonly observed and often linked to volatile loss. The fluids released during the crystallization of the intrusive complex are interpreted to be at the origin of the surrounding high temperature alteration halo. Advanced argillic to potassic alteration and high temperature acidic assemblage is associated with high-temperature quartz veining at depth and vuggy silica at the paleo-surface. Major element compositions of the white micas associated with the high temperature halo show a transition from, muscovite to phengite, muscovitic illite away from the intrusion, with a transition to pyrophyllite and/ or topaz, and andalusite characteristic of more acidic conditions. Abundant high-density (up to 59 wt% NaCl eq and homogenization temperatures of 550 degree Celsius and above) coexist with low-density vapor fluid inclusions. This

  16. The role of CO2-rich fluids in trace element transport and metasomatism in the lithospheric mantle beneath the Central Pannonian Basin, Hungary, based on fluid inclusions in mantle xenoliths

    NASA Astrophysics Data System (ADS)

    Berkesi, Márta; Guzmics, Tibor; Szabó, Csaba; Dubessy, Jean; Bodnar, Robert J.; Hidas, Károly; Ratter, Kitti

    2012-05-01

    Upper mantle peridotite xenoliths from the Tihany Maar Volcanic Complex, Bakony-Balaton Highland Volcanic Field (Central Pannonian Basin, Hungary) contain abundant pyroxene-hosted negative crystal shaped CO2-rich fluid inclusions. The good correlation between enrichment of the clinopyroxenes in Al2O3, TiO2, Na2O, MREE and Zr, and the presence of fluid inclusions in the xenoliths provide strong evidence for fluid-related cryptic metasomatism of the studied xenoliths. The FIB-SEM (focused ion beam-scanning electron microscopy) exposure technique revealed a thin glass film, covering the wall of the fluid inclusions, which provides direct evidence that the silicate components were formerly dissolved in the CO2-rich fluid phase. This means that at upper mantle conditions CO2-rich fluids are capable of transporting trace and major elements, and are the agents responsible for cryptic metasomatism of the peridotite wall rock. Several daughter phases, including magnesite, quartz and sulfide, were identified in the fluid inclusions. Magnesite and quartz are the products of a post entrapment carbonation reaction, whereby the reactants are the CO2-rich fluid and the host orthopyroxene. It is likely that the thin glass film prevented or arrested further growth of the magnesite and quartz by isolating the fluid from the host orthopyroxene, resulting in the preservation of residual CO2 in the fluid inclusions.

  17. Fluids in deeply subducted continental crust: Petrology, mineral chemistry and fluid inclusion of UHP metamorphic veins from the Sulu orogen, eastern China

    NASA Astrophysics Data System (ADS)

    Zhang, Ze-Ming; Shen, Kun; Sun, Wei-Dong; Liu, Yong-Sheng; Liou, J. G.; Shi, Cao; Wang, Jin-Li

    2008-07-01

    The complex vein associations hosted in southern Sulu ultrahigh-pressure (UHP) eclogites contain quartz ± omphacite (or jadeite) ± kyanite ± allanite ± zoisite ± rutile ± garnet. These minerals have chemical compositions similar to those of host eclogites. Inclusions of polycrystalline quartz pseudomorphs after coesite were identified in vein allanite and garnet, and coesite inclusions were found in vein zircon. These facts suggest that the veins together with host eclogites have been subjected to synchronous UHP metamorphism. The vein minerals contain relatively high concentrations of rare earth elements (REE), high-field-strength elements (HFSE) and transition metal elements (TME). A kyanite-quartz vein has a whole-rock composition similar to adjacent UHP metamorphic granitic gneisses. Abundant primary multi-solid fluid inclusions trapped within UHP vein minerals contain complex daughter minerals of muscovite, calcite, anhydrite, magnetite, pyrite, apatite, celestite and liquid and gas phase of H 2O with solids up to 30-70% of the inclusion volume. The presence of daughter minerals anhydrite and magnetite indicates the subduction fluids were oxidizing, and provides a possible interpretation for the high oxygen fugacity of subduction zone magmas. These characteristics imply that the UHP vein minerals were crystallized from supercritical silicate-rich aqueous fluids that were in equilibrium with peak-UHP minerals, and that the fluids in deeply subducted continental crust may contain very high concentrations of silicate as well as HREE, HFSE and TME. Such fluids might have resulted in major fractionation between Nb and Ta, i.e. the UHP fluids have subchondritic Nb/Ta values, whereas the host eclogites after extraction of the fluids have suprachondritic Nb/Ta values. Therefore, voluminous residual eclogites with high Nb/Ta ratios may be the complementary suprachondritic reservoir capable of balancing the subchondritic depleted mantle and continental crust

  18. Oscillations in Phanerozoic seawater chemistry: evidence from fluid inclusions.

    PubMed

    Lowenstein, T K; Timofeeff, M N; Brennan, S T; Hardie, L A; Demicco, R V

    2001-11-01

    Systematic changes in the chemistry of evaporated seawater contained in primary fluid inclusions in marine halites indicate that seawater chemistry has fluctuated during the Phanerozoic. The fluctuations are in phase with oscillations in seafloor spreading rates, volcanism, global sea level, and the primary mineralogies of marine limestones and evaporites. The data suggest that seawater had high Mg2+/Ca2+ ratios (>2.5) and relatively high Na+ concentrations during the Late Precambrian [544 to 543 million years ago (Ma)], Permian (258 to 251 Ma), and Tertiary through the present (40 to 0 Ma), when aragonite and MgSO4 salts were the dominant marine precipitates. Conversely, seawater had low Mg2+/Ca2+ ratios (<2.3) and relatively low Na+ concentrations during the Cambrian (540 to 520 Ma), Silurian (440 to 418 Ma), and Cretaceous (124 to 94 Ma), when calcite was the dominant nonskeletal carbonate and K-, Mg-, and Ca-bearing chloride salts, were the only potash evaporites. PMID:11691988

  19. The fate of fluid inclusions during high-temperature experimental deformation of olivine aggregates

    NASA Astrophysics Data System (ADS)

    Carter, Matthew J.; Zimmerman, Mark E.; Teyssier, Christian

    2015-05-01

    Torsion experiments on initially wet and dry olivine aggregates at equivalent deformation conditions investigated the fate of fluid inclusions (FIs) during high-temperature deformation. Wet samples were produced by adding water to San Carlos olivine powders before hot pressing; those hot pressed without water are considered dry. After hot pressing, wet and dry aggregates have comparable grain sizes, but wet aggregates have more abundant primary FIs. Talc jackets were fitted around some wet and dry samples prior to deformation to hydrate samples during deformation via talc dehydration at elevated temperature, whereas other samples were deformed without talc. At similar strain rates (~1.0 × 10-4 s-1), the peak shear stress for the dry sample (no talc) was 190-220 MPa, whereas all other samples reached 180 MPa; the strengths of wet (± talc) and dry (+ talc) specimens appear similar. Deformed samples reveal abundant FIs, reduced grain size, shape preferred orientation of olivine, and a pervasive low-angle fabric (C') to the shear plane defined by aligned FIs. Samples deformed with talc have FI-rich and FI-depleted domains; where FIs are abundant, the C' fabric is better developed and grain size is smaller. Electron backscatter diffraction pole figures suggest that olivine deformed in the dislocation creep regime via the (010)[100] slip system. Results of these experiments suggest that FIs are redistributed during dislocation creep, leading to the development of grain-scale, high-diffusivity pathways.

  20. Near-infrared spectroscopic determination of salinity and internal pressure of fluid inclusions in minerals.

    PubMed

    Kagi, Hiroyuki; Kiyasu, Akiko; Akagi, Tasuku; Nara, Masayuki; Sawaki, Takayuki

    2006-04-01

    A near-infrared (NIR) spectroscopic method is proposed to achieve the simultaneous determination of salinity and internal pressure of fluid inclusions in natural minerals. A combination band between the anti-symmetric stretching and bending vibrations of molecular water at approximately 5180 cm-1 was observed for standard salt solutions and natural minerals containing fluid inclusions with known salinities. A curve-fitting procedure was used to analyze the change in the band shape of the combination. Justification of the calibration was confirmed by observation of fluid inclusions in natural minerals whose salinities had already been determined using microthermometry. The detection limit of the present method is 1 NaCl-eq wt. %. The minimum size of fluid inclusions that produced well-resolved spectra was approximately 30 microm. This method was applied to assess micro fluid inclusions in a natural diamond with cubic growth habit (cuboid). The salinity and residual pressure of those fluid inclusions were estimated respectively as 4.4 wt. % NaCl-eq and 0.6-0.8 GPa. The present method is complementary to Raman microscopy and microthermometry for the determination of salinity in fluid inclusions of geological samples. PMID:16613640

  1. Magmatic Vapor Phase Transport of Copper in Reduced Porphyry Copper-Gold Deposits: Evidence From PIXE Microanalysis of Fluid Inclusions

    NASA Astrophysics Data System (ADS)

    Rowins, S. M.; Yeats, C. J.; Ryan, C. G.

    2002-05-01

    walls of the inclusion [3,5]. Results indicate that carbonic inclusions possess higher concentrations of Cu (47 to 2387 ppm; mean 453 ppm) compared to aqueous inclusions (5 to 190 ppm; mean 50 ppm). The aqueous inclusions also are much higher in Cl (Na), K, Ca, and Mn, but have similar abundances of Fe, Zn, and Pb. The metal ratios Cu/Fe, Cu/Zn, and Cu/Pb are 2 to 22 times higher in the carbonic inclusions than in the aqueous inclusions. Interpretation of these 17 Mile Hill PIXE data, however, requires some caution because carbonic and aqueous inclusions in a different grain of quartz from the same vein have similarly low concentrations of Cu (38 to 928 ppm), Fe (152 to 1168 ppm), Zn (26 to 162 ppm) and Pb (121 to 914 ppm). For these inclusions, the preferential partitioning of metals apparently has not occurred. These first PIXE data for deposits of the new RPCG subclass demonstrate the greater potential of these systems, compared to the classically oxidized porphyry Cu-Au systems, to transport Cu and probably precious metals in a magmatic aqueous vapor phase. These PIXE data also support the possibility that Cu partitions preferentially into an immiscible CO2-rich magmatic fluid. References: [1] Heinrich, C.A. et al. (1992) Econ. Geol., 87, 1566-1583. [2] Heinrich, C.A. et al. (1999) Geology, 27, 755-758. [3] Rowins, S.M. (2000) Geology, 28, 491-494. [4] Rowins, S.M. (2000) The Gangue, GAC-MDD Newsletter, 67, 1-7 (www.gac.ca). [5] Rowins, S.M. et al. (1993) Geol. Soc. Australia Abs., 34, 68-70.

  2. The Oxygen Isotopic Composition of MIL 090001: A CR2 Chondrite with Abundant Refractory Inclusions

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.; McKeegan, K. D.; Sharp, Z. D.

    2012-01-01

    MIL 090001 is a large (>6 kg) carbonaceous chondrite that was classified as a member of the CV reduced subgroup (CVred) that was recovered during the 2009-2010 ANSMET field season [1]. Based on the abundance of refractory inclusions and the extent of aqueous alteration, Keller [2] suggested a CV2 classification. Here we report additional mineralogical and petrographic data for MIL 090001, its whole-rock oxygen isotopic composition and ion microprobe analyses of individual phases. The whole rock oxygen isotopic analyses show that MIL 090001 should be classified as a CR chondrite.

  3. Raman imaging of fluid inclusions in garnet from UHPM rocks (Kokchetav massif, Northern Kazakhstan).

    PubMed

    Korsakov, Andrey V; Dieing, Thomas; Golovin, Aleksandr V; Toporski, Jan

    2011-10-01

    Confocal Raman imaging of fluid inclusions in garnet porphyroblasts from diamond-grade metamorphic calc-silicate rocks from the Kumdy-Kol microdiamond deposit (Kokchetav Massif, Northern Kazakhstan) reveals that these fluid inclusions consist of almost pure water with different step-daughter phases (e.g., calcite, mica and rare quartz). These fluid inclusions are characterized by negative crystal shape of the host-garnet and they exclusively occur within the core of garnet porphyroblasts. These observations are consistent with their primary origin, most likely at ultrahigh-pressure (UHP) metamorphic conditions. The euhedral newly formed garnet, different in color and composition, was found to be associated with these fluid inclusions. It is proposed that newly formed garnet and water fluid inclusions appear by reaction between the hydrous fluid and the garnet-host. These fluid inclusions provide an unequivocal record of almost pure H(2)O fluids, indicating water-saturated conditions within subducted continental crust during prograde stage and/or ultrahigh-P metamorphism.

  4. Raman imaging of fluid inclusions in garnet from UHPM rocks (Kokchetav massif, Northern Kazakhstan).

    PubMed

    Korsakov, Andrey V; Dieing, Thomas; Golovin, Aleksandr V; Toporski, Jan

    2011-10-01

    Confocal Raman imaging of fluid inclusions in garnet porphyroblasts from diamond-grade metamorphic calc-silicate rocks from the Kumdy-Kol microdiamond deposit (Kokchetav Massif, Northern Kazakhstan) reveals that these fluid inclusions consist of almost pure water with different step-daughter phases (e.g., calcite, mica and rare quartz). These fluid inclusions are characterized by negative crystal shape of the host-garnet and they exclusively occur within the core of garnet porphyroblasts. These observations are consistent with their primary origin, most likely at ultrahigh-pressure (UHP) metamorphic conditions. The euhedral newly formed garnet, different in color and composition, was found to be associated with these fluid inclusions. It is proposed that newly formed garnet and water fluid inclusions appear by reaction between the hydrous fluid and the garnet-host. These fluid inclusions provide an unequivocal record of almost pure H(2)O fluids, indicating water-saturated conditions within subducted continental crust during prograde stage and/or ultrahigh-P metamorphism. PMID:21377920

  5. Preliminary fluid inclusions study in the Bucium Rodu-Frasin Neogene volcanic structure, Metaliferi Mountains, Romania

    NASA Astrophysics Data System (ADS)

    Iatan, E. L.; Berbeleac, I.

    2012-04-01

    Bucium Rodu maar-diatreme and Frasin dome volcanic structures and related Au-Ag epithermal deposits are located in the northeastern part of the South Apuseni Mountains, and belong to Bucium-Rosia Montana-Baia de Aries metallogenic district, within so called "Golden Quadrilateral". The microthermometric measurements were carried out using double polished sections, on bipyramidal magmatic quartz phenocrysts and hydrothermal quartz phenocrysts. Depending on the clarity of the quartz, samples were polished down to 200 - 400 μm thick. A standard microscope for transmitted and reflected light was used for the sample petrography. Linkam THM SG600 heating-freezing stage, combined with a Nikon E 400 microscope and a Nikon DXM 1200F digital camera, were used to measure the fluid inclusions homogenization temperatures. The Frasin magmatic quartz phenocrysts, occurs as well-formed bipyramidal β -form quartz phenocrysts and contain apatite, zircon, melt inclusions and fluid inclusions. They reach up to 1 cm in diameter and their cracks are re-filled with carbonate, sericite and sulfides. The size of fluid inclusions ranges from very fine (2-3 μm) up to 25 μm. Primary and pseudosecondary fluid inclusions are not common, they occur in small groups with sizes ranging between 5-20 μm, having two phases: liquid and vapor. Based on the homogenization temperatures and phase proportions at room temperature, we could separate 2 types/fields of range for primary and pseudosecondary fluid inclusions as follows: 1. Liquid rich fluid inclusions (50-60 vol. % liquid) with Th=370-406°C and 2. Vapor rich fluid inclusions (10-30 vol. % liquid) with Th=420-519°C. All of the fluid inclusions homogenize by the disappearance of the vapor phase. Microthermometric data from hydrothermal quartz crystals were obtained from quartz phenocrysts of carbonate-quartz-base metal sulfides-gold veins of the dacite breccias. Primary fluid inclusions from hydrothermal quartz crystals have sizes up to 50

  6. Mineral and fluid inclusion study of emeralds from the Lake Manyara and Sumbawanga deposits, Tanzania

    NASA Astrophysics Data System (ADS)

    Moroz, I.; Vapnik, Y.; Eliezri, I.; Roth, M.

    2001-08-01

    Mineral and fluid inclusions were investigated in Tanzanian emeralds sampled in the Lake Manyara and Sumbawanga deposits. Microthermometry and Raman microprobe analyses were applied for this study. Primary and pseudosecondary H 2O-CO 2 inclusions, with numerous daughter solid phases, are common in the emeralds from the Lake Manyara deposit. Magnesite, Mg-calcite, aragonite, dolomite, calcite, nahcolite, quartz and chrysoberyl were identified as trapped solids in fluid inclusions. Similar mineral inclusions were also found in the emeralds themselves. The composition of the trapped fluid present at emerald growth is estimated to be a carbonic-rich solution with chloride content of about 6 wt% NaCl equiv. The P-T conditions of emerald growth are as follows: T = 370-470°C and P=3.0-7.0 kbar. Mineral inclusions of phenakite, euclase, bertrandite and helvite are common in the emeralds of the Sumbawanga deposit. CO 2-rich inclusions with an aqueous phase (usually below the detection limit), and CaCl 2-rich inclusions with salinity of up to 17 wt% NaCl equiv. are related to emerald growth. The trapping of fluid inclusions postdates the growth of mineral inclusions. The P-T conditions of emerald growth are as follows: T = 220-300°C and P = 0.7-3.0 kbar.

  7. Asteroidal water within fluid inclusion-bearing halite in an H5 chondrite, Monahans (1998)

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Bodnar, R. J.; Gibson, E. K. Jr; Nyquist, L. E.; Reese, Y.; Shih, C. Y.; Wiesmann, H.

    1999-01-01

    Crystals of halite and sylvite within the Monahans (1998) H5 chondrite contain aqueous fluid inclusions. The fluids are dominantly sodium chloride-potassium chloride brines, but they also contain divalent cations such as iron, magnesium, or calcium. Two possible origins for the brines are indigenous fluids flowing within the asteroid and exogenous fluids delivered into the asteroid surface from a salt-containing icy object.

  8. Fluid inclusion and isotopic evidence on dolomitization, Devonian of Western Canada

    SciTech Connect

    Aulstead, K.L.; Spencer, R.J.; Krouse, H.R. )

    1988-05-01

    The Presqu'ile and Manetoe Facies are diagenetic features developed in Lower and Middle Devonian Formations of the Elk Point Basin (Presqu'ile) and the Mackenzie Shelf (Manetoe). Both facies contain coarsely crystalline dolomite and white sparry dolomite cement. Less extensive diagenetic phases, in order of paragenesis, include fluorite, anhydrite, barite, calcite, quartz, sphalerite and galena. Conditions of dolomitization are outlined from core and outcrop examination, thin section and cathodoluminescent petrography, fluid inclusion analyses, and C and O isotopic data. Fluid inclusion and stable isotope analyses from dolomite are combined to determine the isotopic composition of the dolomitizing fluids. Chemical analyses of fluid inclusion waters are compared with formation water analyses to derive a proposed origin for the diagenetic fluids. Dolomite formed from hot, high salinity fluids early in the diagenetic history of the basin. Limestone was dolomitized as a result of the same process that created white sparry dolomite cement in the Manetoe Facies. Remnants of the dolomitizing fluids are present as formation waters in some Devonian formations in Alberta. Subsequent invasion of meteoric waters produced more dilute diagenetic fluids which resulted in the precipitation of calcite and quartz cement in the Manetoe Facies. These fluids are present in fluid inclusions and are responsible for the low {sup 18}O content of the calcite cement. The temperatures of calcite and quartz formation differ as a function of burial depth within the Manetoe Facies during the Mesozoic and Cenozoic, while the temperature of formation for dolomite does not.

  9. Fluid inclusions in vadose cement with consistent vapor to liquid ratios, Pleistocene Miami Limestone, southeastern Florida

    USGS Publications Warehouse

    Barker, C.E.; Halley, R.B.

    1988-01-01

    Vadose cements in the Late Pleistocene Miami Limestone contain regions with two-phase aqueous fluid inclusions that have consistent vapor to liquid (V-L) ratios. When heated, these seemingly primary inclusions homogenize to a liquid phase in a range between 75??C and 130??C (mean = 100??C) and have final melting temperatures between -0.3?? and 0.0??C. The original distribution of Th was broadened during measurements because of fluid inclusion reequilibration. The narrow range of Th in these fluid inclusions suggest unusually consistent V-L ratios. They occur with small, obscure, single phase liquid-filled inclusions, which infer a low temperature origin (less than 60??C), and contradict the higher temperature origin implied by the two phase inclusions. The diagenetic environment producing these seemingly primary fluid inclusions can be inferred from the origin of the host calcite enclosing them. The ??18O composition of these cements (-4 to-5.5%., PDB) and the fresh water in the fluid inclusions are consistent with precipitation from low-temperature meteoric water. The carbon-isotope composition of the vadose cements that contain only rare two-phase fluid inclusions are comparable to the host rock matrix (??13C between 0 and +4%., PDB). Cements that contain common two-phase fluid-inclusions have a distinctly lighter carbon isotopic composition of -3 to -5%.. The carbon isotope composition of cements that contain common two-phase inclusions are about 6%. lighter than those of other vadose cements; models of early meteoric diagenesis indicate that this is the result of precipitation from water that has been influenced by soil gas CO2. Our hypothesis is that the primary fluid inclusions, those with consistent V-L ratios and the single-phase liquid inclusions, form at near-surface temperature (25??C) and pressure when consistent proportions of soil gas and meteoric water percolating through the vadose zone are trapped within elongate vacuoles. This study corroborates

  10. Fluid inclusions in the Stripa granite and their possible influence on the groundwater chemistry

    USGS Publications Warehouse

    Nordstrom, D.K.; Lindblom, S.; Donahoe, R.J.; Barton, C.C.

    1989-01-01

    Fluid inclusions in quartz and calcite of the Proterozoic Stripa granite, central Sweden, demonstrate that the rock and its fracture fillings have a complex evolutionary history. The majority of inclusions indicate formation during a hydrothermal stage following emplacement of the Stripa pluton. Total salinities of quartz inclusions range from 0-18 eq.wt% NaCl for unfractured rock and from 0-10 eq.wt% for fractured rock. Vein calcites contain up to 25 eq.wt% NaCl but the inclusion size is larger and the population density is lower. Homogenization temperatures are 100-150??C for unfractured rock and 100-250?? for fractured rock. Pressure corrections, assuming immediate post-emplacement conditions of 2 kbar, give temperatures about 160??C higher. Measurements of fluid-inclusion population-densities in quartz range from about 108 inclusions/cm3 in grain quartz to 109 inclusions/cm3 in vein quartz. Residual porosity from inclusion densities has been estimated to be at least 1% which is two orders of magnitude greater than the flow porosity. Breakage and leaching of fluid inclusions is proposed as an hypothesis for the origin of major solutes (Na-Ca-Cl) in the groundwater. Evidence for the hypothesis is based on (1) mass balance-only a small fraction of the inclusions need to leak to account for salt concentrations in the groundwater, (2) chemical signatures- Br Cl ratios of fluid inclusion leachates (0.0101) match those ratios for the deep groundwaters (0.0107), (3) leakage mechanisms-micro-stresses from isostatic rebound or mining activities acting on irregular-shaped inclusions could cause breakage and provide connection with the flow porosity, and (4) experimental studies-water forced through low permeability granites leach significant quantities of salt. This hypothesis is consistent with the available data although alternate hypotheses cannot be excluded. ?? 1989.

  11. Noble gas measurements from tiny water amounts: fluid inclusions in carbonates of speleothemes and coral skeletons

    NASA Astrophysics Data System (ADS)

    Papp, Laszlo; Palcsu, Laszlo; Major, Zoltan

    2010-05-01

    pressure range has been calibrated by measuring ten well known water aliquots between 0.45 mg and 3.14 mg sealed in glass capillaries. With this method, the quantity of the water can be determined better than 1% uncertainty. After the dissolved noble gases has been released from the fluid inclusions, they are collected and separated from each other by a cryo system which consists of a stainless steel empty trap and a trap filled with charcoal. The argon, krypton, xenon fraction and the other chemically active gases (N2, O2, CO2, etc.) are trapped in the stainless steel trap at 25 K, while the isotopes of helium and neon in the charcoal trap held at 10 K. So far, the abundance of helium is not measured, because helium does not play a role in the NGT determination due to radiogenic helium component. The helium is pumped away. The neon is released from the stainless steel trap at temperature of 90 K and admitted to the noble gas mass spectrometer. The ion source is tuned for the best sensitivity for neon. The neon isotopes are detected by an electron multiplier in ion counting mode. The argon, krypton and xenon isotopes are measured simultaneously. The gases are released from the stainless steel trap at 150 K, and introduced into a getter trap in order to be purified from the other non-inert gases. Then the pure argon, krypton, xenon fraction is admitted to the mass spectrometer. The isotopes of argon are detected by a Faraday cup, while krypton and xenon isotopes are detected by an electron multiplier. After every single mass spectrometric measurement fast calibration are executed. The calibration of the mass spectrometric measurement is performed by means of well known air aliquots taken from an air reservoir in which the pressure is 2.0052 Pa. The results of the calibration measurements show that the reproducibility is about 2% for all noble gas isotopes measured. This error in noble gas concentrations results in an uncertainty of about 1 °C or lower in the determination

  12. Entrapment of bacteria in fluid inclusions in laboratory-grown halite.

    PubMed

    Adamski, James C; Roberts, Jennifer A; Goldstein, Robert H

    2006-08-01

    Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.

  13. Entrapment of Bacteria in Fluid Inclusions in Laboratory-Grown Halite

    NASA Astrophysics Data System (ADS)

    Adamski, James C.; Roberts, Jennifer A.; Goldstein, Robert H.

    2006-08-01

    Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.

  14. History of diagenetic fluids in a distant foreland area, Middle and Upper Pennsylvanian, Cherokee basin, Kansas, USA: Fluid inclusion evidence

    NASA Astrophysics Data System (ADS)

    Wojcik, Krzysztof M.; Goldstein, Robert H.; Walton, Anthony W.

    1994-02-01

    Analysis of fluid inclusion data in diagenetic cements from Pennsylvanian limestones and sandstones of the Cherokee basin in southeastern Kansas reveals the succession of diagenetic fluids in a distant foreland of the Arkoma-Ouachita system. This succession includes early low-salinity (0.0-2.4 wt% NaCl eq.) fluids of meteoric affinity (Fluid I) followed by low-temperature Na-Ca-Cl brines (Fluid II with salinities between 8.4 and 24.1 wt% NaCl eq.). Fluids I and II were present in the system during precipitation of early-stage calcite cements at temperatures less than about 50°C. Another Na-Ca-Cl brine (Fluid III with salinity up to 25 wt% NaCl eq.) was present in the system later, at temperatures of maximum burial (at least 80-85°C) and higher. Fluid III is followed by a Na-Cl brine (Fluid IV, with salinities about 19-21 wt% NaCl eq.) characterized by temperatures distinctly higher than maximum burial, up to 150°C. Fluid III and Fluid IV were entrapped during precipitation of late-stage baroque dolomite and Fe-dolomite in Pennsylvanian limestones, and late-stage Fe-dolomite and ankerite in Pennsylvanian sandstones. The record of progression from Fluid III to Fluid IV may have been partially obscured by thermal re-equilibriation of some inclusions during migration of Fluid IV. Fluids with Na-Ca-Cl chemistry (Fluid II and III) were either indigenous subsurface fluids of the Cherokee and Arkoma basins, or might have originated as reflux fluids in a Permian evaporitic basin of Central Kansas. Later Na-Cl brine (Fluid IV) originated in deeper parts of the Arkoma-Ouachita system and might have acquired their salinity by dissolution of hypothetical salts buried beneath the Ouachitas. Temperatures recorded by fluid inclusions in late-diagenetic carbonates are 20-60°C higher than those calculated for the maximum burial of the studied section. This thermal anomaly suggests an advective heat transfer from the Arkoma-Ouachita system onto the shelf of the Cherokee basin

  15. Fluid inclusions and U/Pb dating of the El Pilote Fluorite skarn occurrence: Metallogenic implications

    NASA Astrophysics Data System (ADS)

    Levresse, Gilles; Tritlla, Jordi; Solorio-Munguía, Jose Gregorio; Valencia, Victor; Linares, Porfirio Julio Pinto

    2011-05-01

    The "El Pilote" deposit, located in the Coahuila State (NE Mexico), is a small fluorite-bearing calcic skarn we dated at 28.4 ± 0.4 Ma (U/Pb). Fluid inclusion studies, performed on fluorite, indicate the occurrence of hot, hypersaline fluids, trapped during the prograde stage. The retrograde fluids present progressively lower temperatures and salinities. All this fluid data depicts a coherent scenario where early magmatic-dominated fluids were progressively mixed up with low-temperature, low-salinity meteoric fluids whose predominance indicates the waning of the hydrothermal system.

  16. Retrograde methane-dominated fluid inclusions from high-temperature granulites of Rogaland, southwestern Norway

    SciTech Connect

    Van Den Kerkhof, A.M. ); Touret, J.L.R. ); Maijer, C.; Jansen, J.B.H. )

    1991-09-01

    Non-aqueous inclusions in the high-grade (800-1,000C; 4kbar) metamorphic Rogaland region, southwestern Norway, consist of mixtures of CO{sub 2}-CH{sub 4}-N{sub 2}. In particular the fluid inclusions in quartz veins in migmatites are characterized by high CH{sub 4} concentrations and they were re-equilibrated at temperatures below 500C during isobaric cooling. Observations by microthermometry demonstrated several complicated sequences of phase transitions, including partial and metastable homogenization (at lower temperature than melting), and S-L or S-V transitions. The phase behavior reflects a wide variation in composition and molar volume. Fluid compositions were measured by Raman microspectrometry. By this method, also small amounts of graphite have been detected in CO{sub 2}-CH{sub 4} inclusions. The instantaneous formation of graphite in a CO{sub 2}-CH{sub 4} inclusion by induction of the argon laser beam has been observed which points to the metastability of the CO{sub 2}-CH{sub 4} mixture. The calculated densities of the observed fluid mixtures are relatively low, necessitating a revision of the earlier interpretation of these inclusions as containing pure high-density fluids. Inclusions in quartz, trapped after the peak of metamorphism, record fluid heterogeneity which may present evidence for fluid-deficient metamorphism during the retrograde M2-M3 metamorphism.

  17. Occurrence of silicate melt, carbonate-rich melt and fluid during medium pressure anatexis of metapelitic gneisses (Oberpfalz, Bavaria) revealed by melt and fluid inclusions study

    NASA Astrophysics Data System (ADS)

    Ferrero, Silvio; O'Brien, Patrick; Hecht, Lutz; Wunder, Bernd

    2014-05-01

    In the last decades our understanding of partial melting processes in the lower crust profited from the investigation of fluid inclusions (Touret et al., 2009) and more recently of anatectic melt inclusions (Cesare et al., 2011) within enclaves and high-grade terranes. The latter finding allowed us to directly analyse the original anatectic melt (Ferrero et al., 2012; Bartoli et al., 2013) preserved within peritectic phases, i.e. mainly garnet, but also ilmenite and spinel, before fractionation, mixing and contamination processes took place. Furthermore, the occurrence of primary fluid inclusions (FI) and anatectic melt inclusions (MI) within enclaves allowed the characterization of the COH fluid present during anatexis under fluid+melt immiscibility conditions (Ferrero et al., 2014). Primary crystallized MI, or "nanogranites", and FI have been identified to occur as clusters in garnet from stromatic migmatites (Zeilengneise) from Oberpfalz, Eastern Bavaria (Moldanubian Zone). During the late Carboniferous, these Grt+Bt+Sill+Crd+Spl metapelitic gneisses underwent HT/MP metamorphism, followed by a HT/LP event (Tanner & Behrmann, 1995). Nanogranites, ≤20 µm in size, consist of Qtz+Bt+Wm+Ab±Ap, and show abundant nanoporosity, localized in the quartz. Fluid inclusions are smaller, generally ≤10 µm, and contain CO2+N2+CH4 plus siderite, pyrophillite and cristobalite, mineral phases not observed in the surrounding rock or as mineral inclusion in garnet. Polycrystalline inclusions containing Cc+Wm+Opx±Qz, commonly ≤10 µm in diameter, occur in the same cluster with MI and FI. Microstructural features, negative-crystal shape and the well-developed crystalline faces of calcite within inclusions suggest that they may result from the crystallization of a carbonate-rich melt. The lack of arrays of carbonate-bearing MI, verified by cathodoluminiscence investigation, supports their primary nature, i.e. they formed during garnet growth. This would suggest the occurrence

  18. Genetic characteristics of fluid inclusions in sphalerite from the Silesian-Cracow ores, Poland

    USGS Publications Warehouse

    Kozlowski, A.; Leach, D.L.; Viets, J.G.

    1996-01-01

    Fluid inclusion studies in sphalerite from early-stage Zn-Pb mineralization in the Silesian-Cracow region (southern Poland), yielded homogenization temperatures (Th) from 80 to 158??C. Vertical thermal gradient of the parent fluids was 6 to 10??C, and the ore crystallization temperature ranges varied from <10??C at deep levels to 25??C at shallow levels. The peculiarities of formation of primary and secondary fluid inclusions from organic-matter-bearing water-dominated medium, position of the inclusions in crystals, features of secondary inclusions, the inclusion refilling phenomena, their formation on recrystallization of ores, and Th distribution in single fissure fillings were considered. The ore-forming fluids were liquid-hydrocarbon-bearing aqueous solutions of Na-Ca-Cl type with lower Ca contents in the south and higher Ca contents in the north of the region. The ore-forming fluids had salinities from nul to about 23 weight percent of NaCl equivalent. Three types of fluids were recognized, that mixed during ore precipitation: a) ascending fluids of low-to-moderate salinity and high, b) formation brines of high salinity and moderate Th, and c) descending waters of low salinity and low-to-moderate Th.

  19. Surface water paleotemperatures and chemical compositions from fluid inclusions in Permian Nippewalla Group halite

    SciTech Connect

    Benison, K.C.

    1996-12-31

    Quantitative climatic data for the Permian have been determined from Nippewalla Group halite. The middle Permian Nippewalla Group of Kansas and Oklahoma consists of several hundred feet of bedded halite, anhydrite, and red beds. Study of core and surface samples suggest that this halite was deposited by ephemeral lakes. Fluid inclusions provide evidence for the geochemistry of these Permian saline lake waters, including temperatures, salinities, and chemical compositions. Primary fluid inclusions are well-preserved in the Nippewalla halite. They are 5 - 30 {mu}m cubic inclusions situated along chevron and cornet growth bands. Most are one phase aqueous inclusions, but some also contain anhydride {open_quote}accidental{close_quotes} crystals. Rare two phase liquid-vapor inclusions may have formed by subaqueous outgassing or trapping of air at the water surface. Fluid inclusion freezing-melting behavior and leachate analyses suggest that Nippewalla halite precipitated from Na-Cl-rich waters with lesser quantities of SO{sub 4}, Mg, K, Al, and Si. This composition may be a product of long-term weathering. Surface water paleotemperatures were determined from one phase aqueous fluid inclusions. Homogenization temperatures range from 32 to 46{degrees}C in primary fluid inclusions and are consistent (within 3{degrees}C) along individual chevrons and cornets. These homogenization temperatures are interpreted to represent maximum surface water temperatures. These fluid inclusion data are significant in addressing global change problems. Temperatures and chemistries in these Permian lake waters agree with some modern shallow saline lake waters and with Permian climate models. This study suggests that this Permian environment was relatively similar to its modern counterparts.

  20. Surface water paleotemperatures and chemical compositions from fluid inclusions in Permian Nippewalla Group halite

    SciTech Connect

    Benison, K.C. )

    1996-01-01

    Quantitative climatic data for the Permian have been determined from Nippewalla Group halite. The middle Permian Nippewalla Group of Kansas and Oklahoma consists of several hundred feet of bedded halite, anhydrite, and red beds. Study of core and surface samples suggest that this halite was deposited by ephemeral lakes. Fluid inclusions provide evidence for the geochemistry of these Permian saline lake waters, including temperatures, salinities, and chemical compositions. Primary fluid inclusions are well-preserved in the Nippewalla halite. They are 5 - 30 [mu]m cubic inclusions situated along chevron and cornet growth bands. Most are one phase aqueous inclusions, but some also contain anhydride [open quote]accidental[close quotes] crystals. Rare two phase liquid-vapor inclusions may have formed by subaqueous outgassing or trapping of air at the water surface. Fluid inclusion freezing-melting behavior and leachate analyses suggest that Nippewalla halite precipitated from Na-Cl-rich waters with lesser quantities of SO[sub 4], Mg, K, Al, and Si. This composition may be a product of long-term weathering. Surface water paleotemperatures were determined from one phase aqueous fluid inclusions. Homogenization temperatures range from 32 to 46[degrees]C in primary fluid inclusions and are consistent (within 3[degrees]C) along individual chevrons and cornets. These homogenization temperatures are interpreted to represent maximum surface water temperatures. These fluid inclusion data are significant in addressing global change problems. Temperatures and chemistries in these Permian lake waters agree with some modern shallow saline lake waters and with Permian climate models. This study suggests that this Permian environment was relatively similar to its modern counterparts.

  1. Stable isotope study of fluid inclusions in fluorite from Idaho: implications for continental climates during the Eocene

    USGS Publications Warehouse

    Seal, R.R.; Rye, R.O.

    1993-01-01

    Isotopic studies of fluid inclusions from meteoric water-dominated epithermal ore deposits offer a unique opportunity to study paleoclimates because the fluids can provide direct samples of ancient waters. Fluorite-hosted fluid inclusions from the Eocene (51-50 Ma) epithermal deposits of the Bayhorse mining district, have low salinities and low to moderate homogenization temperatures indicating meteoric origins for the fluids. Oxygen and hydrogen isotope data on inclusion fluids are almost identical to those of modern meteoric waters in the area. The equivalence of the isotope composition of the Eocene inclusion fluids and modern meteoric waters indicates that the Eocene climatic conditions were similar to those today. -from Authors

  2. Development and application of a mass spectrometric system to study volatile components of fluid inclusions

    SciTech Connect

    Sloan, R.C. Jr.

    1992-06-01

    A quadrupole mass spectrometric system coupled with mechanical decrepitation was constructed and calibrated to study fluid inclusions from an active geothermal system. Fluid inclusions in Salton Sea Scientific Drilling Project well cores and ejects from flow tests were analyzed. Ion currents from selected mass/charge ratio numbers were measured for gases from ruptured inclusions in epidote, calcite, and hematite vein minerals from different depths. Water, carbon dioxide, hydrogen sulfide, sulfur dioxide, and C1{minus}C4+ hydrocarbons and free nitrogen were analyzed.

  3. Gas Analysis of Geothermal Fluid Inclusions: A New Technology For Geothermal Exploration

    SciTech Connect

    David I. Norman; Joseph Moore

    2004-03-09

    To increase our knowledge of gaseous species in geothermal systems by fluid inclusion analysis in order to facilitate the use of gas analysis in geothermal exploration. The knowledge of gained by this program can be applied to geothermal exploration, which may expand geothermal production. Knowledge of the gas contents in reservoir fluids can be applied to fluid inclusion gas analysis of drill chip cuttings in a similar fashion as used in the petroleum industry. Thus the results of this project may lower exploration costs both in the initial phase and lower drill hole completion costs. Commercial costs for fluid inclusion analysis done on at 20 feet intervals on chip samples for 10,000 ft oil wells is about $6,000, and the turn around time is a few weeks.

  4. Petrography, fluid inclusion analysis, and geochronology of the End uranium deposit, Kiggavik, Nunavut, Canada

    NASA Astrophysics Data System (ADS)

    Chi, Guoxiang; Haid, Taylor; Quirt, David; Fayek, Mostafa; Blamey, Nigel; Chu, Haixia

    2016-04-01

    The End deposit is one of several uranium deposits in the Kiggavik area near the Proterozoic Thelon Basin, which is geologically similar to the Athabasca Basin known for its unconformity-related uranium deposits. The mineralization occurs as uraninite and coffinite in quartz veins and wall rocks (psammopelitic gneisses) in the sub-Thelon basement and is associated with clay- and hematite-altered fault zones. Fluid inclusions were studied in quartz cementing unmineralized breccias formed before mineralization (Q2), quartz veins that were formed before mineralization but spatially associated with uranite (Q4), and calcite veins that were formed after mineralization. Four types of fluid inclusions were recognized, namely liquid-dominated biphase (liquid + vapor), vapor-dominated biphase (vapor + liquid), monophase (vapor-only), and triphase (liquid + vapor + halite) inclusions. The first three types were found in Q2, whereas all four types were found in Q4 and calcite. The coexistence of these different types of inclusions within individual fluid inclusion assemblages is interpreted to indicate fluid immiscibility and heterogeneous trapping. Based on microthermometry, the fluids associated with Q2 are characterized by low salinities (0.4 to 6.6 wt%) and moderate temperatures from 148 to 261 °C, and the fluids associated with calcite show high salinities (26.8 to 29.3 wt%) and relatively low temperatures from 146 to 205 °C, whereas the fluids associated with Q4 have a wide range of salinities from 0.7 to 38.8 wt% and temperatures from 80 to 332 °C. Microthermometric and cryogenic Raman spectroscopic studies indicate that the high-salinity fluids in Q4 and calcite belong to the H2O-NaCl-CaCl2 ± MgCl2 system, with some dominated by NaCl and others by CaCl2. The fluid inclusions in Q2 are interpreted to be unrelated to mineralization, whereas those in Q4 and calcite reflect the mineralizing fluids. The fluid inclusion data are consistent with a genetic link of

  5. Fluid inclusion geochemistry of halite from the Silurian A-1 Evaporite, Michigan Basin

    SciTech Connect

    Leibold, A.W.; Walter, L.M.; Huston, T.J.; O'Neil, J.R. . Dept. of Geological Sciences)

    1992-01-01

    Fluids trapped in primary, inclusion-rich halite from the Silurian A-1 Evaporite of the Michigan Basin were analyzed to determine their elemental and isotopic composition and so constrain the fluid chemistry and regional variability of parent brines. The samples were collected from stratigraphically more complete basin center and basin margin cores than hitherto have been available. These include both inclusion-rich whole rock chips and fluids leached with isopropanol from crushed, inclusion-rich halite. Elemental ratios were determined relative to Mg, which is present only in the fluid phase of monomineralic halite samples and acts as a normalizing parameter against which to quantify fluid inclusion chemistry. Stable isotope ratios were determined on fluids collected from inclusion-rich halite by vacuum-thermal decrepitation. Inclusion fluids define a geochemical trend characterized by a Ca:Mg ratio of 1.4 [+-] 0.47, an Sr:Mg ratio of 0.015 [+-] 0.004 and a K:Mg ratio of 0.5 [+-] 0.17. Fluids are also depleted in SO[sub 4]. Importantly, these values are significantly different from any Michigan Basin formation brines and also cannot be derived from evaporation of modern seawater without extensive diagenetic modification. Two explanations of the data are possible. Pervasive syndepositional dolomitization and anhydrite precipitation may have altered Silurian brines of initial modern seawater composition, as has been suggested for similar data. However, consistently high cation ratios in the A-1 Evaporite on a regional scale demand striking uniformity in the timing and location of such reactions. Alternatively, Silurian seawater may have had elevated Ca:Mg, Sr:Mg and possibly K:Mg ratios relative to modern seawater.

  6. Evolution of the Geysers (US) - Data From Fluid-Inclusion Microthermometry and Gas Geochemistry

    SciTech Connect

    Moore, J.N.; Hulen, J.B.; Norman, D.I.

    1995-01-01

    The Geysers, California, is the site of an active hydrothermal system that initially developed between about 1.5 and 2 Ma in response to intrusion of a hypabyssal granitic pluton. Mineralogic and fluid-inclusion data demonstrate that the present vapor-dominated regime evolved from an earlier and more extensive, liquid-dominated hydrothermal system. Circulation of these early fluids produced veins characterized by tourmaline and/or biotite {+-} actinolite {+-} clinopyroxene within the pluton and adjacent biotite-rich hornfels, actinolite {+-} ferroaxinite {+-} epidote, and epidote {+-} chlorite {+-} wairakite within the intermediate parts of the thermal system, and calcite in the outer parts. Potassium feldspar and quartz are present in all assemblages. Maximum pressure-corrected homogenization temperatures and apparent salinities of fluid-inclusions in these veins range from 440 C and 44 weight percent NaCl equivalent within the hornfels (<600 m from the pluton) to 325 C and 5 weight percent NaCl equivalent at approximately 1500 m from the intrusion. We suggest that the shallow, moderate-salinity fluids are crustal waters modified by water-rock interactions and that the high-salinity fluids are magmatic brines. The formation of vapor-dominated conditions is reflected in the abrupt appearance of low salinity (0.0 to 0.4 weight percent NaCl equivalent) fluid inclusions with homogenization temperatures near 265 C. These inclusion fluids are thought to represent steam condensate formed as the liquid-dominated system boiled off.

  7. Fluid-Inclusion Petrology - Data from Porphyry Copper Deposits and Applications to Exploration

    USGS Publications Warehouse

    Nash, J. Thomas

    1976-01-01

    Fluid-inclusion studies of 37 porphyry copper deposits, mainly in the United States, demonstrate that all but 3 evolved through a hydrothermal stage characterized by very high salinities, generally in excess of about 35 weight percent NaCI equivalent. Temperatures of these fluids ranged from about 250 deg to 700 deg C for various stages and deposits. Most systems boiled. High salinities, shown by halite-bearing inclusions, and boiling, suggested by coexisting gas and liquid-rich inclusions, are considered to be diagnostic of epizonal intrusions which are the most favorable parents for porphyry copper mineralization. Depth of emplacement of many copper-bearing stocks is deduced from fluid inclusions to have been about 6,000 to 10,000 feet (1,800 to 3,000 metres); fluid pressures during mineralization are interpreted generally to be less than 500 bars. Moderate-salinity (less than about 12 percent) and moderate-temperature <350 deg C) fluids are noted in all porphyry copper deposits and were responsible for the deposition of most copper and molybdenum in deposits, such as Bagdad, Esperanza, Mineral Park, Morenci, Ray, Sierrita, in the Southwestern United States and several in southern British Columbia. However, with only three exceptions, highly saline fluids apparently were present at an early stage and also deposited metals. The relative amounts and economic importance of copper and molybdenum deposited from high- and moderate-salinity fluids varies within the porphyry deposit class. There is compelling geologic and geochemical evidence that chloride is important for transport of metals, but the porphyry coppers stand out as a class associated with fluids of especially high salinity during at least one stage of their formation. Halite cubes in fluid inclusions are an effective, although rough, indicator of those salinities and can be conveniently monitored during petrographic study of thin sections. Thus, fluid inclusions can be used to characterize favorable

  8. Analysis of single oil-bearing fluid inclusions in mid-Proterozoic sandstones (Roper Group, Australia)

    NASA Astrophysics Data System (ADS)

    Siljeström, Sandra; Volk, Herbert; George, Simon C.; Lausmaa, Jukka; Sjövall, Peter; Dutkiewicz, Adriana; Hode, Tomas

    2013-12-01

    Hydrocarbons and organic biomarkers extracted from black shales and other carbonaceous sedimentary rocks are valuable sources of information on the biodiversity and environment of early Earth. However, many Precambrian hydrocarbons including biomarkers are suspected of being younger contamination. An alternative approach is to study biomarkers trapped in oil-bearing fluid inclusions by bulk crushing samples and subsequently analysing the extracted hydrocarbons with gas chromatography-mass spectrometry. However, this method does not constrain the hydrocarbons to one particular oil inclusion, which means that if several different generations of oil inclusions are present in the sample, a mix of the content from these oil inclusions will be analysed. In addition, samples with few and/or small inclusions are often below the detection limit. Recently, we showed that it is possible to detect organic biomarkers in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In the present study, single fluid inclusion analysis has been performed on Proterozoic samples for the first time. Four individual oil-bearing fluid inclusions, found in 1430 Ma sandstone from the Roper Superbasin in Northern Australia, were analysed with ToF-SIMS. The ToF-SIMS spectra of the oil in the different inclusions are very similar to each other and are consistent with the presence of n-alkanes/branched alkanes, monocyclic alkanes, bicyclic alkanes, aromatic hydrocarbons, and tetracyclic and pentacyclic hydrocarbons. These results are in agreement with those obtained from bulk crushing of inclusions trapped in the same samples. The capability to analyse the hydrocarbon and biomarker composition of single oil-bearing fluid inclusions is a major breakthrough, as it opens up a way of obtaining molecular compositional data on ancient oils without the ambiguity of the origin of these hydrocarbons. Additionally, this finding suggests that it will be possible

  9. Preliminary mineralogic, fluid inclusion, and stable isotope study of the Mahd adh Dhahab gold mine, Kingdom of Saudi Arabia

    USGS Publications Warehouse

    Rye, Robert O.; Hall, W.E.; Cunningham, C.G.; Czamanske, G.K.; Afifi, A.M.; Stacey, J.S.

    1983-01-01

    The Mahd adh Dhahab mine, located about 280 km northeast of Jiddah, Kingdom of Saudi Arabia, has yielded more than 2 million ounces of gold from periodic production during the past 3,000 years. A new orebody on the southern side of the ancient workings, known as the South orebody, is being developed by Gold Fields-Mahd adh Dhahab Limited. A suite of samples was collected from the newly exposed orebody for preliminary mineralogic, stable isotope, fluid inclusion, and geochemical studies. The Mahd adh Dhahab deposit is in the carapace of a Proterozoic epizonal rhyolite stock that domed pyroclastic and metasedimentary rocks of the Proterozoic Halaban group. Ore of gold, silver, copper, zinc, tellurium, and lead is associated with north-trending, steeply dipping quartz veins in a zone 1,000 m long and 400 m wide. The veins include an assemblage of quartz-chlorite-pyrite-hematite-chalcopyrite-sphalerite-precious metals, which is similar to the mineral assemblage at the epithermal deposit at Creede, Colorado. The primary ore contains abundant chalcopyrite, sphalerite, and pyrite in addition to a complex precious metal assemblage. Gold and silver occur principally as minute grains of telluride minerals disseminated in quartz-chlorite-hematite and as inclusions in chalcopyrite and sphalerite. Telluride minerals include petzite, hessite, and sylvanite. Free gold is present but not abundant. All of the vein-quartz samples contained abundant, minute inclusions of both low-density, vapor-rich fluids and liquid-rich fluids. Primary fluid inclusions yielded homogenization temperatures of from 110? to 238? C. Preliminary light-stable isotope studies of the sulfide minerals and quartz showed that all of the d34S values are between 1.2 and 6.3 per mil, which is a typical range for hydrothermal sulfide minerals that derive their sulfur from an igneous source. The data-suggest that the sulfide sulfur isotope geochemistry was controlled by exchange with la large sulfur isotope

  10. Rb sbnd Sr isotopic analysis of fluid inclusions in quartz: Evaluation of bulk extraction procedures and geochronometer systematics using synthetic fluid inclusions

    NASA Astrophysics Data System (ADS)

    Pettke, Thomas; Diamond, Larryn W.

    1995-10-01

    Analysis of Rb sbnd Sr isotopic and elemental signatures of fluid inclusions is technically demanding, but it offers enormous potential in elucidating the timing, sources, and geochemical reaction paths of fluids in the Crust. Fluid inclusions of known isotopic and elemental ratios have been synthesized in quartz to serve as control samples. With these standards, two previously used fluid extraction procedures for bulk quartz samples have been evaluated and improved: crushing in a mortar followed by leaching and thermal decrepitation followed by leaching. Our experiments on quartz show that 87Sr/ 86Sr analysis is straightforward using both methods, regardless of the leaching solution employed. However, analysis of accurate 87Rb/ 86Sr ratios is not trivial. Leaching with pure water is only 93% efficient and yields elevated ratios owing to failure to inhibit surface adsorption of Sr. Leaching with a La 3+-doped acid solution solves this problem; it is 99.7% efficient and yields accurate ratios. Crushing is the only fluid liberation method which delivers the correct 87Rb/ 86Sr values. In contrast, thermal decrepitation yields 87Rb/ 86Sr ratios which are quite reproducible, but exclusively incorrect. If inert sample containers are used, falsely elevated ratios are obtained at all decrepitation temperatures due to three concurrent extraction artefacts. However, if silica glass tubes are used, reaction of Rb with the glass at temperatures above ˜ 500°C falsely lowers the 87Rb/ 86Sr signatures. We, therefore, suspect all published isotopic analyses of fluid inclusions obtained by thermal decrepitation to be in error. The trace contents of Rb and Sr in the host quartz crystals are measurable and have markedly different Rb/Sr ratios compared to the hydrothermal parent fluid. Thus analyses of leachates and host-mineral residues by the crushing method allow accurate ages to be calculated with certainties of an order which are useful for geochronology. Since fluid extraction

  11. Fluid inclusion studies of calcite veins from Yucca Mountain, Nevada, Tuffs: Environment of formation

    SciTech Connect

    Roedder, E.; Whelan, J.F.; Vaniman, D.T.

    1994-12-31

    Calcite vein and vug fillings at four depths (130-314m), all above the present water table in USW G-1 bore hole at Yucca Mountain, Nevada, contain primary fluid inclusions with variable vapor/liquid raitos: Most of these inclusions are either full of liquid or full of vapor. The liquid-filled inclusions show that most of the host calcite crystallized from fluids at <100{degrees}C. The vapor-filled inclusions provide evidence that a separate vapor phase was present in the fluid during crystallization. Studies of these vapor-filled inclusions on the microscope crushing stage were interpreted in an earlier paper as indicating trapping of an air-water-CO{sub 2} vapor phase at ``<100{degrees}C``. Our new studies reveal the additional presence of major methane in the vapor-filled inclusion, indicating even lower temperatures of trapping, perhaps at near-surface temperatures. They also show that the host calcite crystals grew from a flowing film of water on the walls of fractures open to the atmosphere, the vapor-filled inclusions representing bubbles that exsolved from this film onto the crystal surface.

  12. Decrepitation and crack healing of fluid inclusions in San Carlos olivine

    SciTech Connect

    Wanamaker, B.J. ); Wong, Tengfong ); Evans, B. )

    1990-09-10

    Fluid inclusions break, or decrepitate, when the fluid pressure exceeds the least principal lithostatic stress by a critical amount. After decrepitation, excess fluid pressure is relaxed, resulting in crack arrest; subsequently, crack healing may occur. The authors developed a linear elastic fracture mechanics model to analyze new data on decrepitation and crack arrest in San Carlos Olivine, compared the model with previous fluid inclusion investigations, and used it to interpret some natural decrepitation microstructures. The common experimental observation that smaller inclusions may sustain higher internal fluid pressures without decrepitating may be rationalized by assuming that flaws associated with the inclusion scale with the inclusion size. According to the model, the length of the crack formed by decrepitation depends on the lithostatic pressure at the initiation of cracking, the initial sizes of the flaw and the inclusion, and the critical stress intensity factor. Further experiments show that microcracks in San Carlos olivine heal within several days at 1,280 to 1,400{degree}C; healing rates depend on the crack geometry, temperature, and chemistry of the buffering gas. The regression distance of the crack tip during healing can be related to time through a power law with exponent n = 0.6. Chemical changes which become apparent after extremely long heat-treatments significantly affect the healing rates. Many of the inclusions in the San Carlos xenoliths stretched, decrepitated, and finally healed during uplift. The crack arrest model indicates that completely healed cracks had an initial fluid pressure of the order of 1 GPa. Using the crack arrest model and the healing kinetics, they estimate the ascent rate of these xenoliths to be between 0.001 and 0.1 m/s.

  13. Fluid-inclusion evidence for previous higher temperatures in the miravalles geothermal field, Costa Rica

    USGS Publications Warehouse

    Bargar, K.E.; Fournier, R.O.

    1988-01-01

    Heating and freezing data were obtained for liquid-rich secondary fluid inclusions in magmatic quartz, hydrothermal calcite and hydrothermal quartz crystals from 19 sampled depths in eight production drill holes (PGM-1, 2, 3, 5, 10, 11, 12 and 15) of the Miravalles geothermal field in northwestern Costa Rica. Homogenization temperatures for 386 fluid inclusions range from near the present measured temperatures to as much as 70??C higher than the maximum measured well temperature of about 240??C. Melting-point temperature measurements for 76 fluid inclusions suggest a calculated salinity range of about 0.2-1.9 wt% NaCl equivalent. Calculated salinities as high as 3.1-4.0 wt% NaCl equivalent for 20 fluid inclusions from the lower part of drill hole PGM-15 (the deepest drill hole) indicate that higher salinity water probably was present in the deeper part of the Miravalles geothermal field at the time these fluid inclusions were formed. ?? 1988.

  14. Unexpected phase assemblages in inclusions with ternary H2O-salt fluids at low temperatures

    NASA Astrophysics Data System (ADS)

    Bakker, Ronald J.; Baumgartner, Miriam

    2012-06-01

    Phase assemblages and temperatures of phase changes provide important information about the bulk properties of fluid inclusions, and are typically obtained by microthermometry. Inclusions are synthesized in natural quartz containing an aqueous fluid with a composition in the ternary systems of H2O-NaCl2-CaCl2, H2O-NaCl-MgCl2, and H2O-CaCl2-MgCl2. This study reveals that these fluid inclusions may behave highly unpredictably at low temperatures due to the formation of metastable phase assemblages. Eutectic temperatures cannot be detected in most of the fluid inclusions containing these ternary systems. Nucleation of a variety of solid ice and salt-hydrate phases in single fluid inclusions is often partly inhibited. Raman spectroscopy at low temperatures provides an important tool for interpreting and understanding microthermometric experiments, and visualizing stable and metastable phase assemblages. Final dissolution temperatures of ice, salt-hydrates, and salt must be treated with care, as they can only be interpreted by purely empirical or thermodynamic models at stable conditions.

  15. Fluid chemistry in the fault propataion zone in the mid-crust -fluid inclusion chemistry from the Lishan fault, Taiwan-

    NASA Astrophysics Data System (ADS)

    Okamoto, K.; Iijima, C.; Kurosawa, M.; Chan, Y.; Terabayashi, M.

    2011-12-01

    Liberation of CO2-rich gas from fluid preserved in the fault propagation zone would be important phenomena in the earthquake and aftershock process. We have detected that injected fluid in link thrust would cause fault propagation and fault lubrication due to vapor-separation [1]. Recently, one of the authors, Yu-Chang Chan found unusual quartz vein on the great link-thrust, Lishan fault, in Taiwan orogenic belt [1]. The quartz vein is spherical shape and is composed of large crystals. The transparent quartz grains contain large primary fluid inclusions over 100 microns in diameters. The fluid inclusion is classified as three kinds of group. That is, two phase, vapor phase and three phase inclusion. Homogenization temperature is 260 oC and NaCl weight pecent is estimated to be 7.41. In order to measure the fluid chemistry, PIXE analysis was done at Tsukuba University. Analytical procedure is shown in [2]. The result is summarized as follows. 1. Br/Cr ratio is lower than that in seawater. 2. Ti, Cr, and Ni contents are high, suggesting that fluid is related to magma activity. 3. Vapor-phase inclusion contains considerable amount of metal elements (Ti, Zn, Ge, Mn, Ca, Fe, Pb, Rb, and Cu) as well as K, and Br. Fractionation between the vapor and the fluid would be useful tool to detect vapor separation due to fault propagation. References [1] Chan, Y. et al., Terra Nova 17, 439-499 (2005) [2] Kurosawa M. et al.,Island Arc, 19, 17-29 (2010)

  16. Paleothermal study of Triassic Formation in Syria by using fluid inclusion

    SciTech Connect

    Bilal, A.

    1988-08-01

    This study of fluid inclusions examined several hundred samples collected from different wells distributed throughout Syria. The results show the existence of aqueous, carbon, and hydrocarbon inclusions. Since aqueous inclusions vary in their common (form, distribution) and physicochemical properties (fusion temperature, homogeneity temperature, density, etc), a chronological relation could be made giving the following results: aqueous inclusions in the detritic minerals (type q/sub 1/) are prediagenesis, and aqueous inclusions related to overgrowth minerals (type q/sub 2/) are contemporary with diagenesis. But type q/sub 3/ aqueous inclusions in the secondary fractures that cross many minerals are post-diagenesis. Therefore, type q/sub 3/ inclusions are used to determine the temperature of Triassic formations, taking into consideration their saltiness (NaCl content is 10%, according to applied data). Carbon and hydrocarbon inclusions are postdiagenesis according to aqueous inclusion type q/sub 2/. By using both the density of type q/sub 2/ aqueous inclusions and the heaviness of the rock overburden according to the depth of the samples studies, thermal gradient can be determined. It ranges between 5 and 7% and increases from the north-northeast toward the west-southwest, i.e., in the direction of tectonic anomaly and volcanic activity connected with the Great Syrian Rift, which is a continuation of the Great African Rift. In addition, thermal gradient increases with depth in every well but is mainly related to the location of the well according to the common trend mentioned above.

  17. Part II. Evaluation of 40Ar- 39Ar quartz ages: Implications for fluid inclusion retentivity and determination of initial 40Ar/ 36Ar values in Proterozoic samples

    NASA Astrophysics Data System (ADS)

    Kendrick, M. A.; Miller, J. McL.; Phillips, D.

    2006-05-01

    The argon isotope systematics of vein-quartz samples with two different K-reservoirs have been evaluated in detail. Potassium is hosted by ultra-high-salinity fluid inclusions in quartz samples from the Eloise and Osborne iron-oxide-copper-gold (IOCG) deposits of the Mt Isa Inlier, Australia. In contrast, K is hosted by accidentally trapped mica within lower-salinity fluid inclusions of a sample selected from the Railway Fault, 13 km south of the Mt Isa copper mine, Australia. Imprecise apparent ages have been obtained for all of the samples studied and conclusively demonstrate that quartz fluid inclusions are retentive to Ar and have not leaked over billions of years. IOCG samples that host K in fluid inclusions only, have K/Cl values of <1 and the ages obtained represent the maximum ages for mineralization. In contrast, the Railway Fault samples that include accidentally trapped mica have K/Cl values of ≫1. Excess 40Ar E plus Cl hosted by fluid inclusions, and radiogenic 40Ar R plus K, are strongly correlated in these samples and define a plane in 3D 40Ar- 36Ar-K-Cl space. In this case, the plane yields an 'excess 40Ar E' corrected age of ˜1030 Ma that is 100's of Ma younger than nearby Cu-mineralization at Mt Isa. The age is interpreted to reflect 40Ar-loss from the accidentally trapped mica into the surrounding fluid inclusions, and is not related to the samples' age of formation. The initial 40Ar/ 36Ar value of fluid inclusions is widely used to provide information on fluid origin. For the IOCG samples that host K in fluid inclusions only, the initial 40Ar/ 36Ar values are close to the measured values at every temperature of stepped heating experiments. For samples that include accidentally trapped mica, the correction for post-entrapment radiogenic 40Ar R production is significant. Furthermore, because 39Ar K present in accidentally trapped mica crystals is released at different temperatures to radiogenic 40Ar R lost to the surrounding fluid inclusions

  18. First evidence of hydrous silicic fluid films around solid inclusions in gem-quality diamonds

    NASA Astrophysics Data System (ADS)

    Nimis, Paolo; Alvaro, Matteo; Nestola, Fabrizio; Angel, Ross J.; Marquardt, Katharina; Rustioni, Greta; Harris, Jeff W.; Marone, Federica

    2016-09-01

    Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 μm. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.

  19. Investigation of biomolecules trapped in fluid inclusions inside halite crystals by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Osterrothová, Kateřina; Jehlička, Jan

    2011-12-01

    Raman spectroscopy was tested for the identification of biomolecules (glycine, L-alanine, β-alanine, L-serine, and γ-aminobutyric acid) trapped in fluid inclusions inside halite model crystals. The investigated biomolecules represent important targets for future astrobiological missions. We know from terrestrial conditions that organic molecules and microorganisms can be sealed within fluid inclusions and can survive intact even for hundreds of millions of years. Raman spectroscopy is currently being miniaturized for future extraterrestrial planetary exploration (ExoMars 2018). Raman spectroscopy has shown the ability to detect investigated aminoacids nondestructively without any sample preparation, in short measurement times, and in relatively low concentrations. The number of registered Raman bands of investigated aminoacids and their intensity clearly correlate with the given concentration of biomolecules within fluid inclusions.

  20. Systematics of stretching of fluid inclusions I: fluorite and sphalerite at 1 atmosphere confining pressure.

    USGS Publications Warehouse

    Bodnar, R.J.; Bethke, P.M.

    1984-01-01

    Measured homogenization T of fluid inclusions in fluorite and sphalerite may be higher than the true homogenization T of samples that have been previously heated in the laboratory or naturally in post-entrapment events. As T and with it internal P is increased, the resulting volume increase may become inelastic. If the volume increase exceeds the precision of T measurement, the inclusion is said to have stretched. More than 1300 measurements on fluid inclusions in fluorite and sphalerite indicate that stretching is systematically related to P-V-T-X properties of the fluid, inclusion size and shape, physical properties of the host mineral, and the confining P. Experimental methods are detailed in an appendix. The mechanism of stretching is probably plastic deformation or - not observed - microfracturing. The systematic relationship between the internal P necessary to initiate stretching and the inclusion volume provides a means of recognizing previously stretched inclusions and estimating the magnitude of post-entrapment thermal events. -G.J.N.

  1. Dynamic transverse shear modulus for a heterogeneous fluid-filled porous solid containing cylindrical inclusions

    NASA Astrophysics Data System (ADS)

    Song, Yongjia; Hu, Hengshan; Rudnicki, John W.; Duan, Yunda

    2016-06-01

    An exact analytical solution is presented for the effective dynamic transverse shear modulus in a heterogeneous fluid-filled porous solid containing cylindrical inclusions. The complex and frequency-dependent properties of the dynamic shear modulus are caused by the physical mechanism of mesoscopic-scale wave-induced fluid flow whose scale is smaller than wavelength but larger than the size of pores. Our model consists of three phases: a long cylindrical inclusion, a cylindrical shell of poroelastic matrix material with different mechanical and/or hydraulic properties than the inclusion and an outer region of effective homogeneous medium of laterally infinite extent. The behavior of both the inclusion and the matrix is described by Biot's consolidation equations, whereas the surrounding effective medium which is used to describe the effective transverse shear properties of the inner poroelastic composite is assumed to be a viscoelastic solid whose complex transverse shear modulus needs to be determined. The determined effective transverse shear modulus is used to quantify the S-wave attenuation and velocity dispersion in heterogeneous fluid-filled poroelastic rocks. The calculation shows the relaxation frequency and relative position of various fluid saturation dispersion curves predicted by this study exhibit very good agreement with those of a previous two-dimensional finite-element simulation. For the double-porosity model (inclusions having a different solid frame than the matrix but the same pore fluid as the matrix) the effective shear modulus also exhibits a size-dependent characteristic that the relaxation frequency moves to lower frequencies by two orders of magnitude if the radius of the cylindrical poroelastic composite increases by one order of magnitude. For the patchy-saturation model (inclusions having the same solid frame as the matrix but with a different pore fluid from the matrix), the heterogeneity in pore fluid cannot cause any attenuation in

  2. Dynamic transverse shear modulus for a heterogeneous fluid-filled porous solid containing cylindrical inclusions

    NASA Astrophysics Data System (ADS)

    Song, Yongjia; Hu, Hengshan; Rudnicki, John W.; Duan, Yunda

    2016-09-01

    An exact analytical solution is presented for the effective dynamic transverse shear modulus in a heterogeneous fluid-filled porous solid containing cylindrical inclusions. The complex and frequency-dependent properties of the dynamic shear modulus are caused by the physical mechanism of mesoscopic-scale wave-induced fluid flow whose scale is smaller than wavelength but larger than the size of pores. Our model consists of three phases: a long cylindrical inclusion, a cylindrical shell of poroelastic matrix material with different mechanical and/or hydraulic properties than the inclusion and an outer region of effective homogeneous medium of laterally infinite extent. The behavior of both the inclusion and the matrix is described by Biot's consolidation equations, whereas the surrounding effective medium which is used to describe the effective transverse shear properties of the inner poroelastic composite is assumed to be a viscoelastic solid whose complex transverse shear modulus needs to be determined. The determined effective transverse shear modulus is used to quantify the S-wave attenuation and velocity dispersion in heterogeneous fluid-filled poroelastic rocks. The calculation shows the relaxation frequency and relative position of various fluid saturation dispersion curves predicted by this study exhibit very good agreement with those of a previous 2-D finite-element simulation. For the double-porosity model (inclusions having a different solid frame than the matrix but the same pore fluid as the matrix) the effective shear modulus also exhibits a size-dependent characteristic that the relaxation frequency moves to lower frequencies by two orders of magnitude if the radius of the cylindrical poroelastic composite increases by one order of magnitude. For the patchy-saturation model (inclusions having the same solid frame as the matrix but with a different pore fluid from the matrix), the heterogeneity in pore fluid cannot cause any attenuation in the

  3. Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression

    SciTech Connect

    Stein, C.L.

    1985-09-01

    A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

  4. Paleotemperature reconstructions from speleothem fluid inclusions between 14 - 10 ka BP in Milandre cave (NW Switzerland)

    NASA Astrophysics Data System (ADS)

    Affolter, Stéphane; Häuselmann, Anamaria; Fleitmann, Dominik; Leuenberger, Markus

    2016-04-01

    In cave environments, speleothems constitute a well preserved and precisely dated continental climate archive that record past environmental changes such as paleotemperature or moisture source, namely through oxygen and hydrogen isotopes variations. Fluid inclusions are common in speleothems and they correspond to micrometric voids that often contain fossil liquid water representing past precipitation falling above the cave nearly at the time the inclusions were sealed. To measure the δD and δ18O isotopic composition of speleothem fluid inclusions, we extracted submicrolitre amounts of water from stalagmites (old and recent) coming from Milandre cave (Switzerland) using a new online method developed at the University of Bern (Affolter et al., 2014). The released water is then flushed directly to a Picarro L1102-i or L2140-i laser based instrument that allows to simultaneously monitor hydrogen and oxygen isotopes. At Milandre cave site, a two year isotope monitoring campaign has confirmed that isotopes in precipitation for northwestern Switzerland are principally controlled by air temperature (Affolter et al., 2015). Therefore, when combined with calcite δ18O, the fluid inclusion water isotopes can be used to calculate paleotemperatures. We reconstructed a cold season biased (roughly autumn - winter - spring) paleotemperature trend for the time interval covering the Allerød, the Younger Dryas cold interval and the early Holocene (13'900 - 9'900 BP). References: Affolter S., Fleitmann D., and Leuenberger M.: New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS), Clim. Past, 10, 1291-1304, doi:10.5194/cp-10-1291-2014, 2014. Affolter S., Häuselmann A.D., Fleitmann D., Häuselmann P., Leuenberger M.: Triple isotope (δD, δ17O, δ18O) study on precipitation, drip water and speleothem fluid inclusions for a Western Central European cave (NW Switzerland), Quat. Sci. Rev., 127, pp. 73-89, 2015.

  5. Fluid inclusion geochemistry of the early Proterozoic Pirilä gold deposit in Rantasalmi, Southeastern Finland

    NASA Astrophysics Data System (ADS)

    Poutiainen, M.

    1993-04-01

    The small Pirilä gold deposit, which is located in the southeastern part of the Svecofennian complex near the Archean/Proterozoic boundary, is hosted by quartz veins and lenses occurring in mica schist. The rocks of the area were metamorphosed under conditions of amphibolite facies. Gold is invariably associated with sulphides. Microthermometry of fluid inclusions in quartz indicates four types of inclusions: (1) weakly saline H2O-CO2 (< 4.0 eq.wt% NaCl) with small amounts of CH4 (< 10 mole% CH4); (2) CO2 (< 10 mole% CH4); (3) CH4; and (4) H2O (< 25 eq.wt% NaCl) with less than 0.85 mole% CO2 in the vapour phase. Texturally these inclusion types are classified as primary (H2O-CO2) and secondary (H2O, CO2 and CH4). Leachate analysis shows that, in addition to Na, the aqueous fluids contain Ca and Fe with minor amounts of K and Mg. The primary H2O-CO2 and the secondary H2O inclusions contain sulphide and unidentified opaque grains, respectively. The secondary CH4 inclusions are often associated with short trails of arsenopyrite grains. Fluid inclusion and geological data suggest ore mineral mobilization, crystallization of host quartz, and deposition of sulphides controlled by the D2 and D3 structures in the presence of a H2O-CO2 fluid mainly during the plastic D3 deformation and during the amphibolite facies metamorphism (i.e. 3.4 kbars/540 670°C). During ductile-brittle deformation (probably D4), precipitation of tectonic remobilized gold from sulphides in fractures occurred in the presence of CH4 and H2O fluids at lowered temperature (< 440°C) and pressure (< 2 kbars).

  6. Age constraints on fluid inclusions in calcite at Yucca Mountain

    SciTech Connect

    Neymark, Leonid A.; Amelin, Yuri V.; Paces, James B.; Peterman, Zell E.; Whelan, Joseph F.

    2001-04-29

    The {sup 207}Pb/{sup 235}U ages for 14 subsamples of opal or chalcedony layers younger than calcite formed at elevated temperature range between 1.88 {+-} 0.05 and 9.7 {+-} 1.5 Ma with most values older than 6-8 Ma. These data indicate that fluids with elevated temperatures have not been present in the unsaturated zone at Yucca Mountain since about 1.9 Ma and most likely since 6-8 Ma. Discordant U-Pb isotope data for chalcedony subsamples representing the massive silica stage in the formation of the coatings are interpreted using a model of the diffusive loss of U decay products. The model gives an age estimate for the time of chalcedony formation around 10-11 Ma, which overlaps ages of clay minerals formed in tuffs below the water table at Yucca Mountain during the Timber Mountain thermal event.

  7. Do Fluid Inclusions That Homogenize by Halite Disappearance Indicate a High Pressure of Formation?

    NASA Astrophysics Data System (ADS)

    Becker, S. P.; Bodnar, R. J.

    2006-05-01

    Fluid inclusions containing halite daughter minerals are common in many silicic intrusive environments, including porphyry copper deposits. The inclusions may display three modes of homogenization during heating: A) halite dissolution (Tm halite) followed by liquid-vapor homogenization (Th L-V), B) simultaneous Th L-V and Tm halite, or C) Th L-V followed by Tm halite. Previous experimental studies of the H2O-NaCl system describe the vapor-saturated halite solubility curve and liquid-vapor curves, allowing researchers to interpret inclusions that homogenize via modes "A" and "B". However, PTX data describing the path for inclusions that homogenize via mode "C" are scarce, and have only been determined experimentally for a composition of 40 weight % NaCl. Therefore, the minimum trapping pressure at halite dissolution cannot be estimated with sufficient accuracy from measured Th L-V and Tm halite values. Because trapping pressure is directly related to depth of formation, the ability to interpret the trapping pressure conditions for inclusions that homogenize via mode "C" has implications for genetic models of porphyry copper formation and may affect exploration strategies in the search for new prospects. To better constrain formation conditions for inclusions that homogenize by halite dissolution, synthetic fluid inclusions were trapped under halite-saturated conditions at pressures of 0.5, 1.0, 2.0, and 3.0 kbar over a range of temperatures from 300 to 500°C. Microthermometric data obtained from these synthetic inclusions were used to develop a relationship between Th L-V and Tm halite which may be used to estimate the minimum trapping pressure of an inclusion that homogenizes via mode "C". Based on these results, trapping pressures for halite-bearing inclusions from several porphyry copper deposits were estimated using data from literature sources. The results indicate formation pressures which are not consistent with shallow crustal conditions for porphyry copper

  8. The Fluid Dynamic Process of Large-scale Mineralization in the Lanping Basin, Yunnan, SW China: Evidence from Fluid Inclusions and Basin Fluid Modeling

    NASA Astrophysics Data System (ADS)

    XUE, Chunji; CHI, Guoxiang; CHEN, Yuchuan; ZENG, Rong; GAO, Yongbao; QING, Hairuo

    The Lanping basin, Yunnan, SW China, is known for the giant Jinding Zn-Pb deposit and the newly-discovered Baiyangping Cu-Co-Ag super-large deposit. With a reserve of ˜ 200 Mt ore grading 6.08% Zn and 1.29% Pb (i.e., a metal reserve of ˜ 15 Mt) hosted in Cretaceous and Tertiary terrestrial rocks, the Jinding deposit is the largest Zn-Pb deposit in China, and also the youngest sediment-hosted and the only continental sediment-hosted super-large Zn-Pb deposit in the world. Differing from the known major types of sediment-hosted Zn-Pb deposits in the world, including SST, MVT and Sedex, the Jinding deposit represents a new type of sediment-hosted Zn-Pb deposits. Most previous studies assumed that the mineralizing fluids were derived from within the basin and the fluid flow was driven by topographic relief under a hydrostatic regime. However, the observations of hydraulic fractures and fluid inclusion data indicate that the mineralizing fluid system was strongly over-pressured. The study of fluid inclusions in sphalerites and associated gangue minerals (quartz, celestite, calcite, and gypsum) shows that homogenization temperatures cluster around 110-150°C, with salinities of 1.6-18.0 wt% NaCl equivalent. The fluid temperature increases with the decrease of salinities during the main ore stages, and there is a systematic westward decrease in temperature and increase in salinity in the Jinding ore district. Fluid pressures as high as (513-1364) × 10 5 Pa are indicated by CO 2-rich fluid inclusions. The basin fluid dynamic modeling results indicate that the overpressures could not have been produced by normal sediment compaction, and the overpressure related to the thrusting may not be enough to explain the high fluid pressures indicated by fluid inclusions. The injection of mantle-derived fluids is likely responsible for the building-up of the high overpressures. The mixing of two types of fluids in a structural-lithologic trap may have been the key dynamic process

  9. Temperatures of quartz cementation in Jurassic sandstones from the Norwegian continental shelf -- evidence from fluid inclusions

    SciTech Connect

    Walderhaug, O. )

    1994-04-01

    Recent studies of fluid inclusions in quartz overgrowths have shown quartz cementation to have taken place at temperatures within the range 60--145 C in several sandstones from the North Sea and offshore mid-Norway (Malley et al. 1986; Konnerup-Madsen and Dypvik 1988; Burley et al. 1989; Walderhaug 1990; Ehrenberg 1990; Saigal et al. 1992; Nedkvitne et al. 1993). This study aims at determining whether these results are typical for quartz cementation of sandstones by presenting homogenization temperatures for 274 aqueous and 366 hydrocarbon inclusions in quartz overgrowths from Jurassic reservoir sandstones on the Norwegian continental shelf, and by reviewing previously published fluid-inclusion data. Possible explanations for different ranges of homogenization temperatures in different sandstones are also discussed, and possible sources of quartz cement and the effect of hydrocarbon emplacement on quartz cementation are considered.

  10. Fluid inclusions in minerals from the geothermal fields of Tuscany, Italy

    USGS Publications Warehouse

    Belkin, H.; de Vivo, B.; Gianelli, G.; Lattanzi, P.

    1985-01-01

    A reconnaissance study on fluid inclusions from the geothermal fields of Tuscany indicates that the hydrothermal minerals were formed by fluids which were, at least in part, boiling. Four types of aqueous inclusions were recognized: (A) two-phase (liquid + vapor) liquid rich, (B) two-phase (vapor + liquid) vapor rich, (C) polyphase hypersaline liquid rich and (D) three phase-H2O liquid + CO2 liquid + CO2-rich vapor. Freezing and heating microthermometric determinations are reported for 230 inclusions from samples from six wells. It is suggested that boiling of an originally homogeneous, moderately saline, CO2-bearing liquid phase produced a residual hypersaline brine and a CO2-rich vapor phase. There are indications of a temperature decrease in the geothermal field of Larderello, especially in its peripheral zones. ?? 1985.

  11. Mantle metasomatism in the Kaapvaal Craton lithosphere: constraints on the composition of the metasomatic agent from fluid inclusions in MARID-type xenoliths

    NASA Astrophysics Data System (ADS)

    Konzett, J.; Krenn, K.; Hauzenberger, Ch.

    2012-04-01

    The emplacement of both group I and group II kimberlites in the Kaapvaal Craton of the Kimberley region in South Africa is associated with an intense metasomatic alteration of the country rocks as evidenced by a diverse suite of xenoliths sampled by the kimberlites mainly comprising metasomatized peridotites and minor MARID-type xenoliths. These are characterized by hydrous potassic silicates and LILE-HFSE-rich titanates. Because the metasomatic agent is not preserved in these rocks its composition has to be inferred from that of the metasomatic assemblages. Here we present for the first time data on fluid inclusions from two MARID-xenoliths sampled by group-I kimberlites of the Kimberley cluster. They provide direct evidence for the nature of the metasomatic fluids involved in kimberlite-related metsomatism. The xenoliths contain phlogopite+K-richterite+diopside+ilmenite±rutile±apatite±zircon. Fluid inclusions with 4-10 µm in size were found in diopside, K-richterite and zircon and contain L+V+one-to-several daughter phases. Investigations with the freezing and heating stage indicate two different chemical systems for the fluids: (1) H2O-NaCl dominant fluids found as L+V+S inclusions in zircon together with abundant needle-like apatite, rutile and phlogopite solid inclusions. The fluid inclusions in part occur along zircon host-rutile/apatite inclusion grain boundaries which indicates that the fluids were trapped during zircon growth. They contain 30-32 mass% NaCl and show a density of 0.87-0.94 g/cm3. Halos of tiny fluid inclusions, however, indicate that most if not all zircon inclusions are decrepitated during ascent from depth and/or superheating during entrainment of the xenoliths into the kimberlite. Using EMPA, enstatite and a SiO2 polymorph were identified in opened fluid inclusions exposed at the surface of polished thin sections. Because these phases were exclusively found in the fluid inclusions, they are considered daughter crystals. The enstatite

  12. Characterization of gas chemistry and noble-gas isotope ratios of inclusion fluids in magmatic-hydrothermal and magmatic-steam alunite

    USGS Publications Warehouse

    Landis, G.P.; Rye, R.O.

    2005-01-01

    Chemical and isotope data were obtained for the active gas and noble gas of inclusion fluids in coarse-grained samples of magmatic-hydrothermal and magmatic-steam alunite from well-studied deposits (Marysvale, Utah; Tambo, Chile; Tapajo??s, Brazil; Cactus, California; Pierina, Peru), most of which are discussed in this Volume. Primary fluid inclusions in the alunite typically are less than 0.2 ??m but range up to several micrometers. Analyses of the active-gas composition of these alunite-hosted inclusion fluids released in vacuo by both crushing and heating indicate consistent differences in the compositions of magmatic-hydrothermal and magmatic-steam fluids. The compositions of fluids released by crushing were influenced by contributions from significant populations of secondary inclusions that trapped largely postdepositional hydrothermal fluids. Thermally released fluids gave the best representation of the fluids that formed primary alunite. The data are consistent with current models for the evolution of magmatic-hydrothermal and magmatic-steam fluids. Magmatic-steam fluids are vapor-dominant, average about 49 mol% H2O, and contain N2, H2, CH4, CO, Ar, He, HF, and HCl, with SO2 the dominant sulfur gas (average SO2/ H2S=202). In contrast, magmatic-hydrothermal fluids are liquid-dominant, average about 88 mol% H2O, and N2, H2, CO2, and HF, with H2S about as abundant as SO2 (average SO2/H2 S=0.7). The low SO2/H2S and N2/Ar ratios, and the near-absence of He in magmatic-hydrothermal fluids, are consistent with their derivation from degassed condensed magmatic fluids whose evolution from reduced-to-oxidized aqueous sulfur species was governed first by rock and then by fluid buffers. The high SO2/H2S and N2/Ar with significant concentrations of He in magmatic-steam fluids are consistent with derivation directly from a magma. None of the data supports the entrainment of atmospheric gases or mixing of air-saturated gases in meteoric water in either magmatic

  13. Constraints from fluid inclusions on sulfide precipitation mechanisms and ore fluid migration in the Viburnum Trend lead district, Missouri

    USGS Publications Warehouse

    Rowan, E.L.; Leach, D.L.

    1989-01-01

    Homogenization temperatures and freezing point depressions were determined for fluid inclusions in Bonneterre Dolomite-hosted dolomite cements in mine samples, as well as drill core from up to 13 km outside of the district. A well-defined cathodoluminescent zonation distinguishes dolomite growth zones as older or younger than main-stage mineralization. Homogenization temperatures and salinities in samples from mines are not systematically different from those of samples outside of the district. The absence of a significant, recognizable decrease in temperature either vertically within the section or east-west across the district, coupled with the minor amount of silica in the district, argues against cooling as a primary cause of sulfide precipitation. In a reduced sulfur mineralization model with Pb carried as chloride complexes, dilution is also a possible sulfide precipitation mechanism. The difference in Pb solubility in the extremes of the chloride concentration range, 3.9 vs. 5.9 molal, reaches 1 ppm only for pH values below approximately 4.5. The distribution of warm inclusions beyond the Viburnum Trend district implies that fluid migration was regional in scale. Elevated temperatures observed in fluid inclusions at shallow stratigraphic depths are consistent with a gravity flow hydrologic system characterized by rapid flow rates and the capacity for advective heat transport. -from Authors

  14. Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy

    SciTech Connect

    Lorie M. Dilley

    2011-03-30

    Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Open or recently closed fractures would be more susceptible to enhancing the permeability of the system. Identifying dense fracture areas as well as large open fractures from small fracture systems will assist in fracture stimulation site selection. Geothermal systems are constantly generating fractures (Moore, Morrow et al. 1987), and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. These fluid inclusions are faithful records of pore fluid chemistry. Fluid inclusions trapped in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. This report presents the results of the project to determine fracture locations by the chemical signatures from gas analysis of fluid inclusions. With this project we hope to test our assumptions that gas chemistry can distinguish if the fractures are open and bearing production fluids or represent prior active fractures and whether there are chemical signs of open fracture systems in the wall rock above the fracture. Fluid Inclusion Stratigraphy (FIS) is a method developed for the geothermal industry which applies the mass quantification of fluid inclusion gas data from drill cuttings and applying known gas ratios and compositions to determine depth profiles of fluid barriers in a modern geothermal system (Dilley, 2009; Dilley et al., 2005; Norman et al., 2005). Identifying key gas signatures associated with fractures for isolating geothermal fluid production is the latest advancement in the application of FIS to geothermal systems (Dilley and Norman, 2005; Dilley and Norman, 2007). Our hypothesis is that peaks in FIS data are related to location of fractures. Previous work (DOE Grant DE-FG36-06GO16057) has indicated differences in the

  15. Towards biomarker analysis of hydrocarbons trapped in individual fluid inclusions: First extraction by ErYAG laser

    NASA Astrophysics Data System (ADS)

    Hode, Tomas; Zebühr, Yngve; Broman, Curt

    2006-12-01

    Fluid inclusions act as sealed vessels containing information about the fluid environment in which the minerals precipitated, and until decrepitated, the chemical composition of the fluid inside the inclusion stays intact. In many cases fluid inclusions contain trapped hydrocarbons, which may provide useful information in paleontological, organic geochemical and astrobiological research since they act as containers of non-contaminated organic matter with a defined minimum age. Here we present a novel concept for extraction of fluid inclusions in preparation for application to extract single fluid inclusions. The method is based on the illumination of a sample with an ErYAG laser ( λ=2940nm). The wavelength of the laser is absorbed by water and organic material, and with the minerals encapsulating the inclusions transparent to the wavelength, the fluid will expand and the inclusion will decrepitate. The initial results of our study demonstrate that fluid inclusions can be extracted by the use of an ErYAG laser, and that organic biomarkers may survive the process, readily available for GC-MS analysis.

  16. Biomarkers from Huronian oil-bearing fluid inclusions: An uncontaminated record of life before the Great Oxidation Event

    NASA Astrophysics Data System (ADS)

    Dutkiewicz, Adriana; Volk, Herbert; George, Simon C.; Ridley, John; Buick, Roger

    2006-06-01

    We report detailed molecular geochemistry of oil-bearing fluid inclusions from a ca. 2.45 Ga fluvial metaconglomerate of the Matinenda Formation at Elliot Lake, Canada. The oil, most likely derived from the conformably overlying McKim Formation, was trapped in quartz and feldspar during diagenesis and early metamorphism of the host rock, probably before ca. 2.2 Ga. The presence of abundant biomarkers for cyanobacteria and eukaryotes derived from and trapped in rocks deposited before the Great Oxidation Event is consistent with an earlier evolution of oxygenic photosynthesis than previously thought and suggests that some aquatic settings had become sufficiently oxygenated for sterol biosynthesis by this time. It also implies that eukaryotes survived several extreme climatic events, including the Paleoproterozoic “snowball Earth” glaciations. The extraction of biomarker molecules from Paleoproterozoic oil-bearing fluid inclusions thus establishes a new method, using low detection limits and system blank levels, to trace evolution of life through Earth's early history that avoids the potential contamination problems affecting shale-hosted hydrocarbons.

  17. Composition of fluid inclusions in Permian salt beds, Palo Duro Basin, Texas, U.S.A.

    USGS Publications Warehouse

    Roedder, E.; d'Angelo, W. M.; Dorrzapf, A.F.; Aruscavage, P. J.

    1987-01-01

    Several methods have been developed and used to extract and chemically analyze the two major types of fluid inclusions in bedded salt from the Palo Duro Basin, Texas. Data on the ratio K: Ca: Mg were obtained on a few of the clouds of tiny inclusions in "chevron" salt, representing the brines from which the salt originally crystallized. Much more complete quantitative data (Na, K, Ca, Mg, Sr, Cl, SO4 and Br) were obtained on ??? 120 individual "large" (mostly ???500 ??m on an edge, i.e., ??? ??? 1.6 ?? 10-4 g) inclusions in recrystallized salt. These latter fluids have a wide range of compositions, even in a given piece of core, indicating that fluids of grossly different composition were present in these salt beds during the several (?) stages of recrystallization. The analytical results indicating very large inter-and intra-sample chemical variation verify the conclusion reached earlier, from petrography and microthermometry, that the inclusion fluids in salt and their solutes are generally polygenetic. The diversity in composition stems from the combination of a variety of sources for the fluids (Permian sea, meteoric, and groundwater, as well as later migrating ground-, formation, or meteoric waters of unknown age), and a variety of subsequent geochemical processes of dissolution, precipitation and rock-water interaction. The compositional data are frequently ambiguous but do provide constraints and may eventually yield a coherent history of the events that produced these beds. Such an understanding of the past history of the evaporite sequence of the Palo Duro Basin should help in predicting the future role of the fluids in the salt if a nuclear waste repository is sited there. ?? 1987.

  18. Fluid flow histories in Permo-Triass sediments of the Sydney Basin, SE Australia; isotope and fluid inclusion constraints

    SciTech Connect

    Hamilton, P.J.; Bai, G.P.

    1996-12-31

    A petrographic, isotopic and fluid inclusion investigation of Permo-Triassic sandstones in the Sydney Basin has enabled reconstruction of the history of fluid flow. Diagenetic cements in Triassic sandstones comprise, in order, grain coating clays and carbonates, pore filling carbonates, kaolin, quartz, late interstitial carbonate and illite. Diagenesis in the Permian sandstones began with pore filling siderite prior to saddle ankerite, followed by quartz and then illite and late carbonates. Fluid rock interaction during burial resulted in increases in pore water 8180 from depositional values of -17{per_thousand} to about -12{per_thousand} to -7{per_thousand} at the time of quartz overgrowth crystallization and to between -7{per_thousand} to -1{per_thousand} at the time of illite crystallisation. Interpretation of fluid inclusion data and maturity measurements indicates that heat flow increased during the Triassic and Jurassic, reaching a maximum of about 2.1 HFU in the Cretaceous. Late Cretaceous uplift, cooling and erosion was initiated at the same time as, and probably related to, the initiation of Tasman Sea rifting. The rocks had previously been more deeply buried by 1500-2100m. The uplift resulted in cessation of illite diagenesis timed at 90Ma and meteoric water invasion of the sandstones in turn causing partial resetting of {delta}D compositions of the diagenetic clays to less D-depleted values.

  19. Fluid flow histories in Permo-Triass sediments of the Sydney Basin, SE Australia; isotope and fluid inclusion constraints

    SciTech Connect

    Hamilton, P.J. ); Bai, G.P. )

    1996-01-01

    A petrographic, isotopic and fluid inclusion investigation of Permo-Triassic sandstones in the Sydney Basin has enabled reconstruction of the history of fluid flow. Diagenetic cements in Triassic sandstones comprise, in order, grain coating clays and carbonates, pore filling carbonates, kaolin, quartz, late interstitial carbonate and illite. Diagenesis in the Permian sandstones began with pore filling siderite prior to saddle ankerite, followed by quartz and then illite and late carbonates. Fluid rock interaction during burial resulted in increases in pore water 8180 from depositional values of -17[per thousand] to about -12[per thousand] to -7[per thousand] at the time of quartz overgrowth crystallization and to between -7[per thousand] to -1[per thousand] at the time of illite crystallisation. Interpretation of fluid inclusion data and maturity measurements indicates that heat flow increased during the Triassic and Jurassic, reaching a maximum of about 2.1 HFU in the Cretaceous. Late Cretaceous uplift, cooling and erosion was initiated at the same time as, and probably related to, the initiation of Tasman Sea rifting. The rocks had previously been more deeply buried by 1500-2100m. The uplift resulted in cessation of illite diagenesis timed at 90Ma and meteoric water invasion of the sandstones in turn causing partial resetting of [delta]D compositions of the diagenetic clays to less D-depleted values.

  20. Fluid inclusions, stable isotopes and gold deposition at Björkdal, northern Sweden

    NASA Astrophysics Data System (ADS)

    Broman, C.; Billström, K.; Gustavsson, K.; Fallick, A. E.

    1994-06-01

    The Björkdal gold deposit is located in the eastern part of the Early Proterozoic Skellefte district in northern Sweden. The ore zone is hosted by a granitoid which intrudes a 1.9 Ga old supracrustal sequence and consists of a network of quartz veins between two shear zones. The ore mineralogy, alteration assemblages, ore fluid characteristics and general setting of the Björkdal deposit reveal many similarities with mesothermal Archean systems. Three types of fluids are represented by fluid inclusions observed in quartz, scheelite and calcite. The first type consists of a CO2-rich fluid which is syngenetic with the formation of the quartz veins. These inclusions occur in quartz and scheelite. Isotopic equilibrium temperatures derived from quartz-scheelite pairs reflect depositional temperatures around 375 °C. Molar volumes of the carbonic fluid inclusions, ranging down to 55 cm3mole, indicate a maximum lithostatic trapping pressure of 1.8 kbar. These fluids were generated at depth in conjunction with early orogenic magma-forming processes. The gold was introduced to the vein system by the carbonic fluid but the gold was deposited after reactions between this fluid and the wall-rock, producing a slightly alkaline, more CH4-rich aqueous type 2 fluid. Fluid inclusions of this chemically modified fluid indicate that the precipitation of the gold, together with pyrrhotite, pyrite and chalcopyrite, occurred under heterogenous conditions at a temperature of 220 °C and a hydrostatic pressure of 0.5 kbar. The gold deposition occurred from fluids with a δ 18O signature of around +8‰ and δD values close to zero per mil. Any metamorphic influence on the stable isotopic signatures is regarded as minimal. The isotope data suggest rather that a surface-derived fluid component had access to the vein system during this process. At a post-vein forming stage (metamorphic stage ?) a secondary episode of gold mobilization occurred as suggested by the aqueous type 3 inclusions

  1. Fluid-inclusion gases in sphalerite, galena, and dolomite from the Silesian-Cracow Zn-Pb district, Poland

    USGS Publications Warehouse

    Leach, D.L.; Apodaca, L.E.; Kozlowski, A.; Landis, G.P.; Hofstra, A.H.

    1996-01-01

    The gases in fluid inclusions from samples of sphalerite, galena, and sparry dolomite from ore deposits in the Silesian-Cracow zinc-lead district were determined by mass spectrometry. The results show that CO2 is the major gas in the fluid inclusions with lesser amounts of CH4. Samples of galena and sphalerite also commonly contain H2S and short-chain hydrocarbon gases. Gases in sphalerite and galena appear to contain two end-member compositions, CO2-CH4 and CO2-H2S bearing fluid inclusions. The apparent end member compositions could represent chemically distinct generations of fluid inclusions trapped at different times or at least two distinct fluids present during ore formation. The presence of distinct fluid inclusion gas compositions is consistent with previous fluid inclusion studies that show the presence of multiple fluids during ore deposition. The presence of multiple fluids in the ore-forming environment could lead to ore precipitation through processes of fluid mixing.

  2. Fluid inclusion and stable isotope data for the Pea Ridge Fe-REE orebody, Missouri

    SciTech Connect

    Sidder, G.B.; Day, W.C.; Rye, R.O. )

    1993-03-01

    New fluid-inclusion and stable-isotope data define the character of the mineralizing fluids that formed the iron and rare-earth-element ore deposit at the Pea Ridge Mine, southeast Missouri. These fluids were very hot and highly saline brines that may have been magmatically derived. Early, pre-magnetite ore skarn alteration of the host rhyolitic tuff took place at temperatures greater than 420 C and possibly as high as 680 C based upon calculated temperatures of quartz-magnetite pairs. Halite homogenization of three- or more phase (liquid + vapor + salts) fluid inclusions in quartz indicates that the skarn-forming fluid had a temperature of about 460 C to > 530 C and a salinity of about 45 to 57 equivalent weight percent NaCl. Analyses of [delta][sup 18]O in quartz from the skarn zone average about 14.5[per thousand], compared to a value of about 13.0[per thousand] for quartz in the host rhyolite. Average [delta][sup 34]S values for pyrite of about 2.3[per thousand] in the skarn zone may reflect a magmatic source. Magnetite ore was deposited at temperatures between about 340 C and 530 C from a fluid with a salinity between about 54 and 60 equivalent weight percent NaCl. The large apparent range of temperatures indicated by both fluid-inclusion and stable-isotope data within each zone may be due to contamination by quartz from multiple stages of quartz deposition. Also, the assumed isotopic equilibrium between some mineral pairs may be incorrect. Moreover, fluid inclusions are relatively rare in all ore and alteration zones except the silicified zone, and only a few inclusions are clearly primary in origin. Nonetheless, the predominance of high temperatures and high salinities in all of the mineralized and altered zones supports the interpretation that Pea ridge is a magmatic hydrothermal deposit. This magmatic hydrothermal model is also supported by paragenetic relations defined by geologic mapping and geochemical modeling of major-, minor-, and trace-element data.

  3. Fluid inclusion and isotopic systematics of an evolving magmatic-hydrothermal system

    SciTech Connect

    Moore, J.N.; Gunderson, R.P.

    1995-10-01

    The Geysers, California, is the site of a long-lived hydrothermal system that initially developed 1.5-2 m.y. ago in response to the intrusion of a hypabyssal granitic pluton. Although wells drilled into The Geysers produce only dry steam, fluid inclusion, isotopic, and mineralogic data demonstrate that the present vapor-dominated regime evolved from an earlier and more extensive, liquid-dominated hydrothermal system. Circulation of these early fluids produced veins characterized by tourmaline {+-} biotite {+-} actinolite {+-} clinopyroxene within the pluton and adjacent biotite-rich hornfels, actinolite {+-} ferroaxinite {+-} epidote and epidote {+-} chlorite within the intermediate parts of the thermal system and calcite in the outer parts. Potassium feldspar and quartz are present in all assemblages. Pressure-corrected homogenization temperatures and apparent salinities of fluid inclusions trapped in vein minerals range from 440{degrees}C and 44 wt% NaCl equivalent within the hornfels (<600 m from the pluton) to 325{degrees}C and 5 wt% NaCl equivalent at distances of approximately 1500 m from the intrusion. We suggest that the shallow, moderate salinity fluids are connate waters modified by water-rock interactions while the high-salinity fluids are interpreted as magmatic brines. Halite-dissolution temperatures of inclusions in the hornfels and pluton indicate that the magnetic fluids were trapped at lithostatic pressures (300-900 bars). In contrast, homogenization temperatures of the connate fluids suggest trapping under hydrostatic pressures of less than several hundred bars. Whole-rock {delta}{sup 18}O values of samples from The Geysers display systematic variations with respect to depth, location within the field, and grade of alteration. At depths below +610 m relative to mean sea level, the {delta}{sup 18}O values are strongly zoned around a northwest-southeast trending low located near the center of the steam reservoir. 77 refs., 15 figs., 2 tabs.

  4. Constraints on hydrocarbon and organic acid abundances in hydrothermal fluids at the Von Damm vent field, Mid-Cayman Rise (Invited)

    NASA Astrophysics Data System (ADS)

    McDermott, J. M.; Seewald, J.; German, C. R.; Sylva, S. P.

    2013-12-01

    The generation of organic compounds in vent fluids has been of interest since the discovery of seafloor hydrothermal systems, due to implications for the sustenance of present-day microbial populations and their potential role in the origin of life on early Earth. Possible sources of organic compounds in hydrothermal systems include microbial production, thermogenic degradation of organic material, and abiotic synthesis. Abiotic organic synthesis reactions may occur during active circulation of seawater-derived fluids through the oceanic crust or within olivine-hosted fluid inclusions containing carbon-rich magmatic volatiles. H2-rich end-member fluids at the Von Damm vent field on the Mid-Cayman Rise, where fluid temperatures reach 226°C, provide an exciting opportunity to examine the extent of abiotic carbon transformations in a highly reducing system. Our results indicate multiple sources of carbon compounds in vent fluids at Von Damm. An ultramafic-influenced hydrothermal system located on the Mount Dent oceanic core complex at 2350 m depth, Von Damm vent fluids contain H2, CH4, and C2+ hydrocarbons in high abundance relative to basalt-hosted vent fields, and in similar abundance to other ultramafic-hosted systems, such as Rainbow and Lost City. The CO2 content and isotopic composition in end-member fluids are virtually identical to bottom seawater, suggesting that seawater DIC is unchanged during hydrothermal circulation of seawater-derived fluids. Accordingly, end-member CH4 that is present in slightly greater abundance than CO2 cannot be generated from reduction of aqueous CO2 during hydrothermal circulation. We postulate that CH4 and C2+ hydrocarbons that are abundantly present in Von Damm vent fluids reflect leaching of fluids from carbon- and H2-rich fluid inclusions hosted in plutonic rocks. Geochemical modeling of carbon speciation in the Von Damm fluids suggests that the relative abundances of CH4, C2+ hydrocarbons, and CO2 are consistent with

  5. Fluid inclusions in microstructures of shocked quartz from the Keurusselkä impact site, Central Finland

    NASA Astrophysics Data System (ADS)

    Poutiainen, Matti; Heikkilä, Pasi

    2013-06-01

    Granitoid rock samples from the assumed center of the Keurusselkä impact site were subjected to a systematic study of fluid-inclusion compositions and densities in various microstructures of the shocked quartz. The results are consistent with the following impact-induced model of formation. After cessation of all major regional tectonic activity and advanced erosional uplift of the Fennoscandian shield, a meteorite impact (approximately 1.1 Ga) caused the formation of planar fractures (PFs) and planar deformation features (PDFs) and the migration of shock-liberated metamorphic fluid (CO2 ± H2O) to the glass in the PDFs. Postimpact annealing of the PDFs led to the formation of CO2 (±H2O) fluid-inclusion decorated PDFs. The scarce fluid-inclusion implosion textures (IPs) suggest a shock pressure of 7.6-10 GPa. The postimpact pressure release and associated heating initiated hydrothermal activity that caused re-opening of some PFs and their partial filling by moderate-salinity/high temperature (>200 °C) H2O (+ chlorite + quartz) and moderate-density CO2. The youngest postimpact endogenic sub- and nonplanar microfractures (MFs) are characterized by low-density CO2 and low-salinity/low-temperature (<200 °C) H2O.

  6. Preservation of hydrocarbons and biomarkers in oil trapped inside fluid inclusions for >2 billion years

    NASA Astrophysics Data System (ADS)

    George, Simon C.; Volk, Herbert; Dutkiewicz, Adriana; Ridley, John; Buick, Roger

    2008-02-01

    Oil-bearing fluid inclusions occur in a ca. 2.45 Ga fluvial metaconglomerate of the Matinenda Formation at Elliot Lake, Canada. The oil, most likely derived from the conformably overlying deltaic McKim Formation, was trapped in quartz and feldspar during diagenesis and early metamorphism of the host rock, probably before ca. 2.2 Ga. Molecular geochemical analyses of the oil reveal a wide range of compounds, including CH 4, CO 2, n-alkanes, isoprenoids, monomethylalkanes, aromatic hydrocarbons, low molecular weight cyclic hydrocarbons, and trace amounts of complex multi-ring biomarkers. Maturity ratios show that the oil was generated in the oil window, with no evidence of extensive thermal cracking. This is remarkable, given that the oils were exposed to upper prehnite-pumpellyite facies metamorphism (280-350 °C) either during migration or after entrapment. The fluid inclusions are closed systems, with high fluid pressures, and contain no clays or other minerals or metals that might catalyse oil-to-gas cracking. These three attributes may all contribute to the thermal stability of the included oil and enable survival of biomarkers and molecular ratios over billions of years. The biomarker geochemistry of the oil in the Matinenda Formation fluid inclusions enables inferences about the organisms that contributed to the organic matter deposited in the Palaeoproterozoic source rocks from which the analysed oil was generated and expelled. The presence of biomarkers produced by cyanobacteria and eukaryotes that are derived from and trapped in rocks deposited before ca. 2.2 Ga is consistent with an earlier evolution of oxygenic photosynthesis and suggests that some aquatic settings had become sufficiently oxygenated for sterol biosynthesis by this time. The extraction of biomarker molecules from Palaeoproterozoic oil-bearing fluid inclusions thus establishes a new method, using low detection limits and system blank levels, to trace evolution through Earth's early history

  7. A new method for synthesizing fluid inclusions in fused silica capillaries containing organic and inorganic material

    USGS Publications Warehouse

    Chou, I.-Ming; Song, Y.; Burruss, R.C.

    2008-01-01

    Considerable advances in our understanding of physicochemical properties of geological fluids and their roles in many geological processes have been achieved by the use of synthetic fluid inclusions. We have developed a new method to synthesize fluid inclusions containing organic and inorganic material in fused silica capillary tubing. We have used both round (0.3 mm OD and 0.05 or 0.1 mm ID) and square cross-section tubing (0.3 ?? 0.3 mm with 0.05 ?? 0.05 mm or 0.1 ?? 0.1 mm cavities). For microthermometric measurements in a USGS-type heating-cooling stage, sample capsules must be less than 25 mm in length. The square-sectioned capsules have the advantage of providing images without optical distortion. However, the maximum internal pressure (P; about 100 MPa at 22 ??C) and temperature (T; about 500 ??C) maintained by the square-sectioned capsules are less than those held by the round-sectioned capsules (about 300 MPa at room T, and T up to 650 ??C). The fused silica capsules can be applied to a wide range of problems of interest in fluid inclusion and hydrothermal research, such as creating standards for the calibration of thermocouples in heating-cooling stages and frequency shifts in Raman spectrometers. The fused silica capsules can also be used as containers for hydrothermal reactions, especially for organic samples, including individual hydrocarbons, crude oils, and gases, such as cracking of C18H38 between 350 and 400 ??C, isotopic exchanges between C18H38 and D2O and between C19D40 and H2O at similar temperatures. Results of these types of studies provide information on the kinetics of oil cracking and the changes of oil composition under thermal stress. When compared with synthesis of fluid inclusions formed by healing fractures in quartz or other minerals or by overgrowth of quartz at elevated P-T conditions, the new fused-silica method has the following advantages: (1) it is simple; (2) fluid inclusions without the presence of water can be formed; (3

  8. Solubility-temperature-salinity diagrams as a means for interpreting fluid-inclusion/mineral-zoning data from the Creede District, Colorado

    SciTech Connect

    Plumlee, G.S.; Hayba, D.O.

    1985-01-01

    Boiling and fluid mixing, which are widely regarded as effective ore-deposition mechanisms, can be differentiated by plotting fluid-inclusion data on temperature (enthalpy)-salinity diagrams. Solubilities of ore and gangue minerals can also be contoured on these diagrams to evaluate the relative chemical effects of mixing and boiling, and thereby reconcile ore-deposition models based on fluid-inclusion data with mineral-zoning patterns. For example, fluid-inclusion data from epithermal vein mineralization at Creede indicate the progressive mixing of metal-bearing brines with overlying ground water. Along this mixing path, solubility contours for sphalerite indicate a change of several orders of magnitude, consistent with the abundant sphalerite found in the northern veins. Temperatures and salinities are as high as 285/sup 0/C and 11.5 wt% NaCl eq. in these sulfide-rich northern veins, but as low as 160-200/sup 0/C and 2-7 wt% NaCl eq. in the barite-rich southern veins. Solubility-temperature-salinity (STS) diagrams show barite solubility changes relatively little at high temperatures and salinities, but drops significantly only at salinities below approx.6 wt% eq. Fluid mixing was the depositional mechanism for barite because most mixing paths cross solubility contours while boiling paths are parallel to them. Thus hot, saline fluids originating in the northern parts of the district deposited mainly sphalerite and galena, but only after significant cooling and dilution did they deposit the large quantities of barite seen in the southern parts of the district. STS diagrams are thus useful for visualizing chemical influences on mineral-zoning patterns and relating mineral solubilities to fluid-inclusion data.

  9. Conditions for veining in the Barrandian Basin (Lower Palaeozoic), Czech Republic: evidence from fluid inclusion and apatite fission track analysis

    NASA Astrophysics Data System (ADS)

    Suchy, V.; Dobes, P.; Filip, J.; Stejskal, M.; Zeman, A.

    2002-04-01

    The interplay between fracture propagation and fluid composition and circulation has been examined by deciphering vein sequences in Silurian and Devonian limestones and shales at Kosov quarry in the Barrandian Basin. Three successive vein generations were recognised that can be attributed to different stages of a basinal cycle. Almost all generations of fracture cements host abundant liquid hydrocarbon inclusions that indicate repeated episodes of petroleum migration through the strata during burial, tectonic compression and uplift. The earliest veins that propagated prior to folding were displacive fibrous "beef" calcite veins occurring parallel to the bedding of some shale beds. Hydrocarbon inclusions within calcite possess homogenisation temperatures between 58 and 68 °C and show that the "beef" calcites originated in the deeper burial environment, during early petroleum migration from overpressured shales. E-W-striking extension veins that postdate "beef" calcite formed in response to Variscan orogenic deformations. Based on apatite fission track analysis (AFTA) data and other geological evidence, the veins probably formed 380-315 Ma ago, roughly coinciding with peak burial heating of the strata, folding and the intrusion of Variscan synorogenic granites. The veins that crosscut diagenetic cements and low-amplitude stylolites in host limestones are oriented semi-vertically to the bedding plane and are filled with cloudy, twinned calcite, idiomorphic smoky quartz and residues of hardened bitumen. Calcite and quartz cements contain abundant blue and blue-green-fluorescing primary inclusions of liquid hydrocarbons that homogenise between 50 and 110 °C. Geochemical characteristics of the fluids as revealed by gas chromatography-mass spectrometry, particularly the presence of olefins and parent aromatic hydrocarbons (phenonthrene), suggest that the oil entrapped in the inclusions experienced intense but geologically fast heating that resulted in thermal pyrolysis

  10. Low-sulfur epithermal gold mineralization at Inca de Oro, northern Chile: Mineralogy and fluid inclusions

    NASA Astrophysics Data System (ADS)

    Palacios M., C.; Lahsen A., A.; Sylvester, H.

    1992-10-01

    Gold mineralization during the Late Cretaceous produced an epithermal deposit of the low-sulfur (adularia-sericite) type, consisting of disseminated gold, gold-copper veins, and stockworks in Jurassic volcanic rocks and Upper Cretaceous quartz monzodiorite and quartz diorite intrusions. The host rock of the disseminated deposits is a silica cap, which represents the near-surface expression of the epithermal system, and the ore mineralogy consists of pyrite, gold, and minor cinnabar. Silicic alteration is represented by cryptocrystalline quartz, and argillic and advanced alteration by kaolinite, jarosite, and minor alunite. Fluid inclusion studies indicate that alteration occurred at 100-200°C from fluids with a salinity of 0.5-5 wt% NaCl equiv. These were probably acid-sulfate waters formed by oxidation of H 2S at the water table. In veins and stockworks, the ore assemblage consists of pyrite, gold, sphalerite, argentite, galena, electrum, chalcopyrite, copper-sulfosalts, bismuthinite, molybdenite, and cinnabar. Adularia-illite-chlorite alteration is closely connected with the stockorrk and vein mineralization. Alteration assemblage and fluid inclusion studies suggest mineralization by near-neutral alkali-chloride boiling fluids at 225-250°C, ranging in salinity from 1 to 14 wt% NaCl equiv., and pressure estimates based on fluid-inclusion data suggest a depth of 300-400 m below the paleosurface. Fracture permeability, combined with a large geothermal gradient, favored the circulation of fluids and development of the geothermal system that caused the mineralization and associated alteration.

  11. Interpretation of fluid inclusions in quartz deformed by weak ductile shearing: reconstruction of differential stress magnitudes and pre-deformation fluid properties

    NASA Astrophysics Data System (ADS)

    Tarantola, Alexandre; Diamond, Larryn W.

    2015-04-01

    A well developed theoretical framework is available in which paleofluid properties, such as chemical composition and density, can be reconstructed from fluid inclusions in minerals that have undergone no ductile deformation. Fluid inclusions are known to reequilibrate during strong post-entrapment changes in hydrostatic confining pressure (e.g. Sterner and Bodnar 1989). The present study extends this framework to encompass fluid inclusions hosted by quartz that has undergone weak ductile deformation following fluid entrapment. Recent piston-cylinder experiments (Griggs apparatus) made on single quartz crystals have shown that such deformation causes inclusions to become dismembered into clusters of irregularly shaped relict inclusions surrounded by planar arrays of tiny, new-formed (neonate) inclusions (Diamond et al. 2010; Tarantola et al. 2010, 2012). Comparison of the experimental samples with a naturally sheared quartz vein from Grimsel Pass, Central Alps, Switzerland, reveals striking similarities. This strong concordance justifies applying the experimentally derived rules of fluid inclusion behaviour to nature. Thus, planar arrays of dismembered inclusions defining cleavage planes in quartz may be taken as diagnostic of small amounts of intracrystalline strain. Deformed inclusions preserve their pre-deformation concentration ratios of gases to electrolytes, but their H2O contents typically have changed. Morphologically intact inclusions, in contrast, preserve the pre-deformation composition and density of their originally trapped fluid. The orientation of the maximum principal compressive stress (σ1) at the time of shear deformation can be derived from the pole to the cleavage plane within which the dismembered inclusions are aligned. Finally, the density of neonate inclusions is commensurate with the pressure value of σ1 at the temperature and time of deformation. This last rule offers a means to estimate magnitudes of shear stresses from fluid inclusion

  12. Ore genesis constraints on the Idaho Cobalt Belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses

    USGS Publications Warehouse

    Hofstra, Albert H.; Landis, Gary P.

    2012-01-01

    The Idaho cobalt belt is a 60-km-long alignment of deposits composed of cobaltite, Co pyrite, chalcopyrite, and gold with anomalous Nb, Y, Be, and rare-earth elements (REEs) in a quartz-biotite-tourmaline gangue hosted in Mesoproterozoic metasedimentary rocks of the Lemhi Group. It is the largest cobalt resource in the United States with historic production from the Blackbird Mine. All of the deposits were deformed and metamorphosed to upper greenschist-lower amphibolite grade in the Cretaceous. They occur near a 1377 Ma anorogenic bimodal plutonic complex. The enhanced solubility of Fe, Co, Cu, and Au as chloride complexes together with gangue biotite rich in Fe and Cl and gangue quartz containing hypersaline inclusions allows that hot saline fluids were involved. The isotopes of B in gangue tourmaline are suggestive of a marine source, whereas those of Pb in ore suggest a U ± Th-enriched source. The ore and gangue minerals in this belt may have trapped components in fluid inclusions that are distinct from those in post-ore minerals and metamorphic minerals. Such components can potentially be identified and distinguished by their relative abundances in contrasting samples. Therefore, we obtained samples of Co and Cu sulfides, gangue quartz, biotite, and tourmaline and post-ore quartz veins as well as Cretaceous metamorphic garnet and determined the gas, noble gas isotope, and ion ratios of fluid inclusion extracts by mass spectrometry and ion chromatography. The most abundant gases present in extracts from each sample type are biased toward the gas-rich population of inclusions trapped during maximum burial and metamorphism. All have CO2/CH4 and N2/Ar ratios of evolved crustal fluids, and many yield a range of H2-CH4-CO2-H2S equilibration temperatures consistent with the metamorphic grade. Cretaceous garnet and post-ore minerals have high RH and RS values suggestive of reduced sulfidic conditions. Most extracts have anomalous 4He produced by decay of U and Th and

  13. A New Method of Obtaining High-Resolution Paleoclimate Records from Speleothem Fluid Inclusions

    NASA Astrophysics Data System (ADS)

    Logan, A. J.; Horton, T. W.

    2010-12-01

    We present a new method for stable hydrogen and oxygen isotope analysis of ancient drip water trapped within cave speleothems. Our method improves on existing fluid inclusion isotopic analytical techniques in that it decreases the sample size by a factor of ten or more, dramatically improving the spatial and temporal precision of fluid inclusion-based paleoclimatology. Published thermal extraction methods require large samples (c. 150 mg) and temperatures high enough (c. 500-900°C) to cause calcite decomposition, which is also associated with isotopic fractionation of the trapped fluids. Extraction by crushing faces similar challenges, where the failure to extract all the trapped fluid can result in isotopic fractionation, and samples in excess of 500 mg are required. Our new method combines the strengths of these published thermal and crushing methods using continuous-flow isotope ratio analytical techniques. Our method combines relatively low-temperature (~250°C) thermal decrepitation with cryogenic trapping across a switching valve sample loop. In brief, ~20 mg carbonate samples are dried (75°C for >1 hour) and heated (250°C for >1 hour) in a quartz sample chamber under a continuously flowing stream of ultra-high purity helium. Heating of the sample chamber is achieved by use of a tube furnace. Fluids released during the heating step are trapped in a coiled stainless steel cold trap (~ -98°C) serving as the sample loop in a 6-way switching valve. Trapped fluids are subsequently injected into a high-temperature conversion elemental analyzer by switching the valve and rapidly thawing the trap. This approach yielded accurate and precise measurements of injected liquid water IAEA reference materials (GISP; SMOW2; SLAP2) for both hydrogen and oxygen isotopic compositions. Blanking tests performed on the extraction line demonstrate extremely low line-blank peak heights (<50mv). Our tests also demonstrate that complete recovery of liquid water is possible and that

  14. Comparison of synthetic fluid inclusion and quartz-trap methods for determining platinum- group element (PGE) solubility in hydrous salt melts at magmatic conditions

    NASA Astrophysics Data System (ADS)

    Hanley, J. J.

    2007-12-01

    Layered intrusions preserve magmatic inclusions containing hydrous halide melt phases composed of transition metal chlorides with less than 5 wt% H2O. Previous attempts at measuring platinum-group element (PGE) solubility in such high salinity volatiles through the analysis of synthetic fluid inclusions have shown that, although the PGE appear to be highly soluble at geologically-realistic conditions, it is difficult to determine if trapped fluids represent equilibrium fluid compositions. Wide ranges in trapped metal content may result from (i) premature formation of fluid inclusions owing to rapid rates of silicate mineral healing (i.e., hours at magmatic conditions in a saline fluid), (ii) premature entrapment of fluids in which the approach to equilibrium metal solubility requires the generation of the metal-complexing ligands (e.g., HCl) from a slow fluid-mineral or fluid- melt buffer reaction, (iii) the dissolution and reprecipitation of PGE in opened inclusions due to subtle temperature or chemical gradients in run capsules, or (iv) heterogeneous fluid compositions due to the presence of PGE micronuggets or colloids that are more abundant near metal-fluid or metal-buffer interfaces. To circumvent some of the problems associated with synthetic inclusion methods, the solubility of platinum in a hydrous salt melt (S-free; 75 wt% CaCl2+MgCl2, 25 wt% H2O) was investigated at elevated T (700°C) and low crustal pressure. The salt melts were reacted with PtAs2 (natural sperrylite) in Pt capsules buffered at an oxygen fugacity of FMQ-1 using a mixed gas buffer and by the solid mineral assemblage tremolite- diopside-enstatite-quartz which fixes the concentration of relevant metal-complexing ligands at run conditions. Salt melts were trapped (simultaneously) in the matrix of a quartz trap (granulated natural quartz partially isolated in a smaller gold capsule) and in synthetic melt inclusions trapped in pre-fractured quartz. After quenching, the melt inclusions and

  15. Fluid inclusion chemistry of adularia-sericite epithermal Au-Ag deposits of the southern Hauraki Goldfield, New Zealand

    USGS Publications Warehouse

    Simpson, Mark P.; Strmic Palinkas, Sabina; Mauk, Jeffrey L.; Bodnar, Robert J.

    2015-01-01

    LA-ICP-MS analyses show that in some cases different fluid inclusion assemblages (FIAs) within a single sample trapped fluids with variable chemistries. These differences likely reflect modification of a single parent fluid through mineral dissolution and precipitation, water/rock interactions, boiling and vapor loss, conductive cooling, and mixing.

  16. Inclusion.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1992-01-01

    This theme journal issue focuses on current activities of the Office of Special Education and Rehabilitative Services which stress inclusion of students with disabilities in the mainstream. It begins with a message from the Assistant Secretary, Robert R. Davila which examines the full meaning of an "inclusive" education. Next, Barbara Buswell and…

  17. Observation of crack propagation in saline ice and freshwater ice with fluid inclusion

    NASA Astrophysics Data System (ADS)

    Arakawa, M.; Petrenko, V. F.

    2003-01-01

    A key process of crack propagation in saline ice is the interaction between the crack and fluid inclusions. We observed their interaction in freshwater ice using very high-speed photography (VHSP) and found that the low-density fluids (air and inert liquid, Fluorinert, 1.78 g/cm(3)) could not impede the crack effectively, interrupting the propagation for less than 10 mus. The high-density liquid mercury, (13.8 g/cm(3)) impeded the crack more effectively, stalling the development of the crack for more than 20 mus. The crack velocity in saline ice was measured using two different methods: electrical resistance method (ERM) and VHSP. These two methods returned very different mean velocities, 15 m/s for the ERM and 250 m/s for the VHSP. We found that in ice with conductive liquid inclusions, the ERM measured the time it took to break liquid bridges stretched across a crack rather than the crack velocity. Results from the VHSP show that the maximum crack velocity in saline ice was 500 m/s, which is one-half of that found in freshwater ice. From our results using freshwater ice with inclusions, we conclude that liquid inclusions in saline ice may play a role in this retardation.

  18. Fluid inclusion and stable isotope study of telluride mineralization at Mahd Adh Dhahab, Saudi Arabia

    SciTech Connect

    Afifi, A.M.; Kelly, W.C.

    1985-01-01

    Mahd Adh Dhahab is unique among Precambrian gold deposits in that it displays many characteristics of epithermal precious metal districts. Au-Ag-Cu-Zn-Pb mineralization occurs principally in the third of five generations of quartz veins. Sulfur isotopic equilibrium was generally maintained among sulfides which range in delta/sup 34/S from -1.8 (galena) to 6.4 (pyrite). The narrow range in delta/sup 34/S of sulfides is inconsistent with large variations in f02 calculated from chlorite +/- pyrite +/- hematite assemblages. Galena-sphalerite pairs yield temperatures in the range 160-270/sup 0/C for stage 3 veins, which fall within the 120-300/sup 0/C range defined by fluid inclusion thermometry. Fluid salinities are in the range 0.5 wt.% NaCl equivalent. The trends indicate mixing of delta/sup 18/O approx. = 0 waters with heavier more oxidized waters during stage 4 deposition which led to non-equilibrium oxidation of H/sub 2/S. deltaD values of vein chlorites fall within a narrow range of -65 to -75, while deltaD measurements of inclusion fluids in quartz display a wider spread from -13 to -43; the lighter values may reflect contamination by secondary inclusions. The stable isotope data indicate probable derivation of both sulfur and carbon from igneous sources. District-wide variation in sulfur and oxygen isotopes indicate the presence of several hydrothermal centers, which has possible significance to exploration.

  19. Oxygen isotopic abundances in calcium- aluminum-rich inclusions from ordinary chondrites: implications for nebular heterogeneity.

    PubMed

    McKeegan, K D; Leshin, L A; Russell, S S; MacPherson, G J

    1998-04-17

    The oxygen isotopic compositions of two calcium-aluminum-rich inclusions (CAIs) from the unequilibrated ordinary chondrite meteorites Quinyambie and Semarkona are enriched in 16O by an amount similar to that in CAIs from carbonaceous chondrites. This may indicate that most CAIs formed in a restricted region of the solar nebula and were then unevenly distributed throughout the various chondrite accretion regions. The Semarkona CAI is isotopically homogeneous and contains highly 16O-enriched melilite, supporting the hypothesis that all CAI minerals were originally 16O-rich, but that in most carbonaceous chondrite inclusions some minerals exchanged oxygen isotopes with an external reservoir following crystallization.

  20. Morphological ripening of fluid inclusions and coupled zone-refining in quartz crystals revealed by cathodoluminescence imaging: Implications for CL-petrography, fluid inclusion analysis and trace-element geothermometry

    NASA Astrophysics Data System (ADS)

    Lambrecht, Glenn; Diamond, Larryn William

    2014-09-01

    Cathodoluminescence (CL) studies have previously shown that some secondary fluid inclusions in luminescent quartz are surrounded by dark, non-luminescent patches, resulting from fracture-sealing by late, trace-element-poor quartz. This finding has led to the tacit generalization that all dark CL patches indicate influx of low temperature, late-stage fluids. In this study we have examined natural and synthetic hydrothermal quartz crystals using CL imaging supplemented by in-situ elemental analysis. The results lead us to propose that all natural, liquid-water-bearing inclusions in quartz, whether trapped on former crystal growth surfaces (i.e., of primary origin) or in healed fractures (i.e., of pseudosecondary or secondary origin), are surrounded by three-dimensional, non-luminescent patches. Cross-cutting relations show that the patches form after entrapment of the fluid inclusions and therefore they are not diagnostic of the timing of fluid entrapment. Instead, the dark patches reveal the mechanism by which fluid inclusions spontaneously approach morphological equilibrium and purify their host quartz over geological time. Fluid inclusions that contain solvent water perpetually dissolve and reprecipitate their walls, gradually adopting low-energy euhedral and equant shapes. Defects in the host quartz constitute solubility gradients that drive physical migration of the inclusions over distances of tens of μm (commonly) up to several mm (rarely). Inclusions thus sequester from their walls any trace elements (e.g., Li, Al, Na, Ti) present in excess of equilibrium concentrations, thereby chemically purifying their host crystals in a process analogous to industrial zone refining. Non-luminescent patches of quartz are left in their wake. Fluid inclusions that contain no liquid water as solvent (e.g., inclusions of low-density H2O vapor or other non-aqueous volatiles) do not undergo this process and therefore do not migrate, do not modify their shapes with time, and are

  1. Laser microprobe analyses of Cl, Br, I, and K in fluid inclusions: Implications for sources of salinity in some ancient hydrothermal fluids

    SciTech Connect

    Boehlke, J.K. ); Irwin, J.J. )

    1992-01-01

    The relative concentrations of Cl, Br, I, and K in fluid inclusions in hydrothermal minerals were measured by laser microprobe noble gas mass spectrometry on irradiated samples containing 10{sup {minus}10} to 10{sup {minus}8} liter of fluid. Distinctive halogen signatures indicate contrasting sources of fluid salinity in fluid inclusions from representative magmatic' (St. Austell), metamorphic' (Alleghany), and geothermal' (Creede, Salton Sea) aqueous systems. Br/Cl mol ratios are lowest at Salton Sea (0.27-0.33 {times} 10{sup {minus}3}); intermediate at St. Austell (0.85 {times} 10{sup {minus}3}), possibly representative of magmatic volatiles; and highest at Creede (1.5-2.1 {times} 10{sup {minus}3}) and Alleghany (1.2-2.4 {times} 10{sup {minus}3}). I/Cl mol ratios are lowest at Creede (1-14 {times} 10{sup {minus}6}); intermediate at Salton Sea (24-26 {times} 10{sup {minus}6}) and St. Austell (81 {times} 10{sup {minus}6}); and highest at Alleghany (320-940 {times} 10{sup {minus}6}). K/Cl mol ratios indicate disequilibrium with respect to hypothetical feldspathic alkali-Al-silicate mineral buffers at fluid inclusion trapping temperatures at Creede, and large contributions of (Na, K)-bicarbonate to total fluid ionic strength at Alleghany. Significant variations in Cl/Br/I/K ratios among different fluid inclusion types are correlated with previously documented mineralization stages at Creede, and with the apparent oxidation state of dissolved carbon at Alleghany. The new data indicate that Cl/Br/I ratios in hydrothermal fluid inclusions vary by several orders of magnitude, as they do in modern surface and ground waters. This study demonstrates that halogen signatures of fluid inclusions determined by microanalysis yield important information about sources of fluid salinity and provide excellent definition of fluid reservoirs and tracers of flow and interaction in ancient hydrothermal systems.

  2. Fluid-deposited graphitic inclusions in quartz: Comparison between KTB (German Continental Deep-Drilling) core samples and artificially reequilibrated natural inclusions

    USGS Publications Warehouse

    Pasteris, J.D.; Chou, I.-Ming

    1998-01-01

    We used Raman microsampling spectroscopy (RMS) to determine the degree of crystallinity of minute (2-15 ??m) graphite inclusions in quartz in two sets of samples: experimentally reequilibrated fluid inclusions in a natural quartz grain and biotite-bearing paragneisses from the KTB deep drillhole in SE Germany. Our sequential reequilibration experiments at 725??C on initially pure CO2 inclusions in a quartz wafer and the J. Krautheim (1993) experiments at 900-1100??C on organic compounds heated in gold or platinum capsules suggest that, at a given temperature, (1) fluid-deposited graphite will have a lower crystallinity than metamorphosed organic matter and (2) that the crystallinity of fluid-deposited graphite is affected by the composition of the fluid from which it was deposited. We determined that the precipitation of more-crystalline graphite is favored by lower fH2 (higher fO2), and that the crystallinity of graphite is established by the conditions (including gas fugacities) that pertain as the fluid first reaches graphite saturation. Graphite inclusions within quartz grains in the KTB rocks show a wide range in crystallinity index, reflecting three episodes of carbon entrapment under different metamorphic conditions. Isolated graphite inclusions have the spectral properties of totally ordered, completely crystalline graphite. Such crystallinity suggests that the graphite was incorporated from the surrounding metasedimentary rocks, which underwent metamorphism at upper amphibolite-facies conditions. Much of the fluid-deposited graphite in fluid inclusions, however, shows some spectral disorder. The properties of that graphite resemble those of experimental precipitates at temperatures in excess of 700??C and at elevated pressures, suggesting that the inclusions represent precipitates from C-O-H fluids trapped under conditions near those of peak metamorphism at the KTB site. In contrast, graphite that is intimately associated with chlorite and other

  3. Fluid inclusion characteristics and geological significance of the Dajinshan W-Sn polymetallic deposit in Yunfu, Guangdong Province

    NASA Astrophysics Data System (ADS)

    Yu, Zhangfa; Chen, Maohong; Zhao, Haijie

    2015-05-01

    The Dajinshan tungsten-tin polymetallic deposit is a quartz-vein-type ore deposit located in Western Guangdong Province. The ore bodies show a fairly simple shape and mainly occur as tungsten-tin polymetallic-bearing sulfide quartz veins, including quartz vein, quartz-greisens, and sulfide quartz veins, and their distribution is spatially related to Dajinshan granitoids. The formation of the deposit experienced three stages: a wolframite-molybdenite-quartz stage, a wolframite-cassiterite-sulfide-quartz stage, and a fluorite-calcite-carbonate stage. Based on detailed petrographic observations, we conducted microthermometric and Raman microspectroscopic studies of fluid inclusions formed at different ore-forming stages in the Dajinshan tungsten-tin polymetallic deposit, identifying four dominant types of fluid inclusions: aqueous two-phase inclusions, CO2-bearing inclusions, solid or daughter mineral-bearing inclusions, and gas-rich inclusions. The gas compositions of ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit are mostly CO2, CH4, and H2O. The hydrogen, oxygen, and sulfur isotopic data imply that the ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit were mainly derived from magmatic fluids, mixed with meteoric water in the ore-formation process. These results indicate that the fluid mixing and boiling led to the decomposition of the metal complex in ore-forming fluids and ore deposition.

  4. Fluid inclusions in veins from the Middle Devonian shales. A record of deformation conditions and fluid evolution in the Appalachian plateau

    SciTech Connect

    Evans, M.A.

    1995-03-01

    Fluid inclusion microthermometric analysis of multiple vein sets from the Middle Devonian shales provides insight into deformation conditions and fluid evolution in the Appalachian Plateau during, and since, the Alleghanian orogeny. The data illustrate a dynamic system in which deformation conditions and fluid compositions changed continually during basin subsidence in response to orogeny and postorogenic uplift and denudation. Two types of inclusions are present in the veins: (1) hydrocarbon inclusions that contain CH{sub 4}, C{sub 2}H{sub 6}, CO{sub 2}, higher hydrocarbons (more than two carbon atoms), and bitumen and (2) two-phase aqueous inclusions that contain very saline (up to 27 wt% NaCl equivalent) NaCl-CaCl{sub 2} brines. The earliest vein set, CFJV1 (cross-fold joints and veins 1), formed during the onset of hydrocarbon generation at a depth of nearly 2.3 km and contains inclusions that are composed of degraded bitumen. The next youngest vein set, CFJV2a, formed under lithostatic pore-fluid pressure conditions at a depth of at least 2.3 km and contains primary inclusions with condensate-like composition. The youngest vein set, strike-parallel SJV (strike joints and veins), formed during maximum burial, or early during uplift, of the Middle Devonian shale section. SJV, along with reopened cross-fold joints and veins, contains barite with nearly pure CH{sub 4} inclusions and two-phase aqueous inclusions. 75 refs., 12 figs., 5 tabs.

  5. Fluid-inclusion data on samples from Creede, Colorado, in relation to mineral paragenesis

    USGS Publications Warehouse

    Woods, T.L.; Roedder, Edwin; Bethke, P.M.

    1982-01-01

    Published and unpublished data on 2575 fluid inclusions in ore and gangue minerals from the Creede, Colorado, Ag-Pb-Zn-Cu vein deposit collected in our laboratories from 1959 to 1981 have shown that the average salinity (wt. % NaCl equivalent, hereinafter termed wt.% eq.) and homogenization temperature (Th), and the ranges of these two parameters for fluid inclusions in sphalerite, quartz, fluorite, and rhodochrosite, respectively, are 8.1 (4.6 - 13.4), 239?C (195-274?C); 6.1 (1.1-10.0), 260?C (190->400?C); 10.7 (6.1-11.1), 217?C (213-229?C) and 260?C (247-268?C) (bimodal distribution of Th); and 9.9 (9.3 - 10.6), 214?C (185-249?C). Inclusions have been measured in minerals from four of the five stages of mineralization previously recognized at Creede. The few inclusions of fluids depositing rhodochrosite (A-stage, earliest in the paragenesis) yield Th and salinity values more similar to those of the low-temperature (average Th 217?C) fluids forming some of the much later fluorite (C-stage) than to any of the other fluids. Th measurements on A-stage quartz range from 192?C to 263?C and average 237?C. The early, fine-grained, B-stage sphalerites yielded Th of 214 to 241?C and salinities of 6.1 to 10.2 wt. % eq. D-stage sphalerite (late in the paragenesis) has been studied in detail (growth-zone by growth-zone) for several localities along the OH vein and reveals a generally positive correlation among Th, salinity and iron content of the host sphalerite. The deposition of D-stage sphalerite was characterized by repeated cycling through different regions of salinity/Th space, as Th and salinity generally decreased with time. Seventeen salinity-Th measurements were made on D-stage sphalerite from one locality on the Bulldog Mountain vein system, which, like the OH vein, is one of four major ore-producing vein systems at Creede. These data suggest a lower Th for a given salinity fluid from sphalerite on the Bulldog Mountain vein than on the OH vein. The very high values

  6. Limit for the Survivability from Potassium Decay of Bacterial Spores in Halite Fluid Inclusions

    NASA Astrophysics Data System (ADS)

    Kminek, G.; Bada, J. L.

    2001-12-01

    Vreeland et al.1 recently claimed to have isolated and cultured a viable spore forming halotolerant bacterium from a 250 million year old brine inclusion present in a salt crystal from the Salado formation. An earlier report suggested that viable bacterial spores could be revived from samples obtained from insects entombed in 25-40 million year old Dominican amber2. On the bases of these reports, Parkes3 raised the question of whether bacterial spores under some conditions might be effectively immortal. Sporulation, induced by an adverse change in the environmental conditions, is able to stabilize the DNA primarily against hydrolytic depurination for extended periods of time4. However, the organism is still exposed to ionizing radiation from the environment. Dormant spores have a reduced sensitivity to ionizing radiation per se, but unlike active organisms are unable to repair DNA damage encountered during long-term exposure to ionizing radiation. The accumulated damage may overwhelm any repair mechanism that starts in the early stage of spore germination5. The main radionuclide in a halite fluid inclusion is 40K, which accounts for 0.0117% of natural potassium. 40K decays via beta decay to 40Ca and via electron capture to 40Ar, releasing a primary gamma-ray. About 83.3 % of the beta's emitted are in the energy range of 0.3-1.3 MeV. We assume 7 g/l for an average concentration of natural potassium in a halite fluid inclusion, which means that the amount of 40K in a 10 μ l fluid inclusion is 8.19 ng. We have chosen a 10 μ l because this volume is typical of that used to obtain chemical data and in the attempts to extract bacteria. Less than a percent of the gamma decay energy is absorbed in a fluid inclusion of 10 μ l. Thus, we will not take the gamma decay energy into account for the further discussion. Almost all the beta energy is absorbed in the fluid inclusion. The total decay energy absorbed in a time period of 250 million years is about 87 kGy. The most

  7. Re-equilibration of primary fluid inclusions in peritectic garnet from metapelitic enclaves, El Hoyazo, Spain

    NASA Astrophysics Data System (ADS)

    Ferrero, Silvio; Bodnar, Robert J.; Cesare, Bernardo; Viti, Cecilia

    2011-05-01

    Primary-appearing fluid (FI) and melt (FI) inclusions occur in peritectic garnet from restitic enclaves from El Hoyazo (Spain). The inclusions were trapped under conditions of immiscibility during partial melting of the enclaves. Trapped fluids in Bt-Grt-Sil and Spl-Crd enclaves have been characterized by microthermometric, Raman spectroscopic, electron microprobe (EMP) and transmission electron microprobe (TEM) analyses to better constrain melt and fluid products and pressure conditions of the partial melting event. In Bt-Grt-Sil enclaves, FI are one phase and contain a CO2-N2 mixture, sometimes with graphite as trapped phase. In Spl-Crd enclaves, FI are two phase and contain an H2O-rich (≤ 90 mol%), with minor amounts of CO2, N2, and traces of H2S and CH4. Graphite often occurs as a trapped phase in the H2O-rich FI, and rare carbonates and other accessory minerals are also observed. Although decrepitation features are not recognized during examination with a petrographic microscope, FI densities based on mass balance constraints are always lower than expected at the inferred PT conditions of entrapment, 5-7 kbar and 800-900 °C. Extremely low densities (≈ 0.1 g cm- 1) of FI in Bt-Grt-Sil enclaves suggest a pressure ≤ 500 bar at 800-900 °C, while densities up to 0.53 g cm- 1 in Spl-Crd enclaves indicate P ≤ 3 kbar at 800-900 °C. Re-equilibration is likely to have occurred via partial decrepitation, as suggested by TEM studies that show rare partially annealed sub-μm cracks, containing small cavities, which may have been the pathways for fluid movement out of the inclusions. MI coexisting with FI have a rhyolitic, peraluminous composition, with higher H2O contents of MI in Spl-Crd enclaves (≈ 9 wt.%) compared to MI in Bt-Grt-Sil enclaves (≈ 3 wt.%). Based on published data, peritectic garnet in Spl-Crd enclaves grew in the presence of a leucogranitic melt saturated in an H2O-rich fluid, in good agreement with the inferred garnet PT growth conditions

  8. A method for temperature estimation in high-temperature geothermal reservoirs by using synthetic fluid inclusions

    NASA Astrophysics Data System (ADS)

    Ruggieri, Giovanni; Orlando, Andrea; Chiarantini, Laura; Borrini, Daniele; Weisenberger, Tobias B.

    2016-04-01

    Super-hot geothermal systems in magmatic areas are a possible target for the future geothermal exploration either for the direct exploitation of fluids or as a potential reservoirs of Enhanced Geothermal Systems. Reservoir temperature measurements are crucial for the assessment of the geothermal resources, however temperature determination in the high-temperature (>380°C) zone of super-hot geothermal systems is difficult or impossible by using either mechanical temperature and pressure gauges (Kuster device) and electronic devices. In the framework of Integrated Methods for Advanced Geothermal Exploration (IMAGE) project, we developed a method to measure high reservoir temperature by the production of synthetic fluid inclusions within an apparatus that will be placed in the high-temperature zone of geothermal wells. First experiments were carried out by placing a gold capsule containing pre-fractured quartz and an aqueous solution (10 wt.% NaCl + 0.4 wt.% NaOH) in an externally heated pressure vessel. Experimental pressure-temperature conditions (i.e. 80-300 bars and 280-400°C) were set close to the liquid/vapour curve of pure H2O or along the H2O critical isochore. The experiments showed that synthetic fluid inclusions form within a relatively short time (even in 48 hours) and that temperatures calculated from homogenization temperatures and isochores of newly formed inclusions are close to experimental temperatures. A second set of laboratory experiments were carried out by using a stainless steel micro-rector in which a gold capsule (containing the pre-fractured quartz and the aqueous solution) was inserted together with an amount of distilled water corresponding to the critical density of water. These experiments were conducted by leaving the new micro-reactor within a furnace at 400°C and were aimed to reproduce the temperature existing in super-hot geothermal wells. Synthetic fluid inclusions formed during the experiments had trapping temperature

  9. Trace-element compositions and Br/Cl ratios of fluid inclusions in the Tsushima granite, Japan: Significance for formation of granite-derived fluids

    NASA Astrophysics Data System (ADS)

    Kurosawa, Masanori; Sasa, Kimikazu; Shin, Ki-Choel; Ishii, Satoshi

    2016-06-01

    Fluid inclusions in quartz samples from a miarolitic cavity, two quartz veins, and a hydrothermal ore vein in the Tsushima granite, Japan, were analyzed by particle-induced X-ray emission to examine the chemistry and process of formation of hydrothermal fluids in an island-arc granite. Most of the inclusions were polyphase or vapor, and there were smaller numbers of two-phase aqueous inclusions. The inclusions contained Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Ge, Br, Rb, Sr, Ba, and Pb. For each inclusion, there was a strong positive correlation between Cl content and contents of other elements identified. Concentration ranges for most elements (other than Rb and Ge) in polyphase inclusions from the miarolitic cavity were comparable to those from cavities in alkaline granites; those from the ore vein were comparable to large-scale continental hydrothermal ore deposits. The lower Rb and higher Ge contents in the polyphase inclusions of the Tsushima granite may be characteristic of hydrothermal fluids from calc-alkaline granites in an island-arc setting. Br/Cl ratios (by weight) for the vapor and two-phase inclusions were 0.0013-0.0030 and differed among the three geological settings. Br/Cl ratios of polyphase inclusions increased with increasing Cl content in single-crystal and polycrystalline quartz, and high values of more than 0.0100 were found. The high Br/Cl ratios and the differences among the geological settings sampled may be due to pressure dependences of partitioning of Cl and Br between fluid and magma during fluid segregation and between liquid and vapor during boiling. Using a simple model based on these dependences, we calculated Br/Cl ratios greater than 0.01 in brine generated at pressures <0.89 kbar. Differences in Br/Cl ratios in polyphase and vapor inclusions from each geological setting were attributed to mixing between two end-member fluids: a high Br/Cl fluid generated at low pressure and a low Br/Cl fluid generated at high pressure. Br/Cl ratios of

  10. Acidophilic Halophilic Microorganisms in Fluid Inclusions in Halite from Lake Magic, Western Australia

    PubMed Central

    Conner, Amber J.

    2013-01-01

    Abstract Lake Magic is one of the most extreme of hundreds of ephemeral acid-saline lakes in southern Western Australia. It has pH as low as 1.7, salinity as high as 32% total dissolved solids, temperatures ranging from 0°C to 50°C, and an unusually complex aqueous composition. Optical petrography, UV-vis petrography, and laser Raman spectrometry were used to detect microorganisms and organic compounds within primary fluid inclusions in modern bedded halite from Lake Magic. Rare prokaryotes appear as 1–3 μm, bright cocci that fluoresce green with UV-vis illumination. Dimpled, 5–7 μm yellow spherules that fluoresce blue with UV-vis illumination are interpreted as Dunaliella algae. Yellow-orange beta-carotene crystals, globules, and coatings are characterized by orange-red fluorescence and three distinct Raman peaks. Because acid saline lakes are good Mars analogues, the documentation of prokaryotes, eukaryotes, and organic compounds preserved in the halite here has implications for the search for life on Mars. Missions to Mars should incorporate such in situ optical and chemical examination of martian evaporites for possible microorganisms and/or organic compounds in fluid inclusions. Key Words: Acid—Extremophiles—Western Australia—Fluid inclusions—Lake Magic—Dunaliella. Astrobiology 13, 850–860. PMID:23971647

  11. Geology, fluid inclusion and sulphur isotope characteristics of the El Cobre VHMS deposit, Southern Cuba

    NASA Astrophysics Data System (ADS)

    Cazañas, Xiomara; Alfonso, Pura; Melgarejo, Joan Carles; Proenza, Joaquín Antonio; Fallick, Anthony Edward

    2008-09-01

    The El Cobre deposit is located in eastern Cuba within the volcanosedimentary sequence of the Sierra Maestra Paleogene arc. The deposit is hosted by tholeiitic basalts, andesites and tuffs and comprises thick stratiform barite and anhydrite bodies, three stratabound disseminated up to massive sulphide bodies produced by silicification and sulphidation of limestones or sulphates, an anhydrite stockwork and a siliceous stockwork, grading downwards to quartz veins. Sulphides are mainly pyrite, chalcopyrite and sphalerite; gold occurs in the stratabound ores. Fluid inclusions measured in sphalerite, quartz, anhydrite and calcite show salinities between 2.3 and 5.7 wt% NaCl eq. and homogenisation temperatures between 177 and 300°C. Sulphides from the stratabound mineralisation display δ 34S values of 0‰ to +6.0‰, whilst those from the feeder zone lie between -1.4‰ and +7.3‰. Sulphides show an intra-grain sulphur isotope zonation of about 2‰; usually, δ 34S values increase towards the rims. Sulphate sulphur has δ 34S in the range of +17‰ to +21‰, except two samples with values of +5.9‰ and +7.7‰. Sulphur isotope data indicate that the thermochemical reduction of sulphate from a hydrothermal fluid of seawater origin was the main source of sulphide sulphur and that most of the sulphates precipitated by heating of seawater. The structure of the deposit, mineralogy, fluid inclusion and isotope data suggest that the deposit formed from seawater-derived fluids with probably minor supply of magmatic fluids.

  12. Fluid inclusions and isotopic characteristics of the Jiawula Pb-Zn-Ag deposit, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Li, Tiegang; Wu, Guang; Liu, Jun; Hu, Yanqing; Zhang, Yunfu; Luo, Dafeng; Mao, Zhihao

    2015-05-01

    The large Jiawula Pb-Zn-Ag deposit is located in the Derbugan metallogenic belt of the northern Great Xing'an Range. The vein style orebodies of the deposit occur along NWW- to NNW-trending fault zones. The ore-forming process at the deposit can be divided into three stages: an early quartz-pyrite-pyrrhotite-chalcopyrite stage, a middle quartz-carbonate-pyrite-galena-sphalerite stage, and a late quartz-carbonate-pyrite stage. Sulfide Rb-Sr dating indicates that the Jiawula deposit formed at ca. 143-142 Ma. Four types of fluid inclusions have been distinguished in quartz veins including liquid-rich, gas-rich, H2O-CO2, and daughter mineral-bearing inclusions. The fluid inclusions of the early stage are mainly liquid-rich, gas-rich, and H2O-CO2 types, with a small number containing daughter minerals. Cumulatively, the types have homogenization temperatures, densities, and salinities of 304-438 °C, 0.35-1.37 g/cm3, and 0.8-44.6 wt.% NaCl eqv., respectively. Inclusions of the middle stage are mainly liquid-rich and gas-rich types, with a small amount of H2O-CO2 and daughter mineral-bearing types; their homogenization temperatures, densities, and salinities vary from 242 °C to 297 °C, 0.71 to 1.44 g/cm3, and 0.4 wt.% to 36.8 wt.% NaCl eqv., respectively. The late stage only comprises liquid-rich inclusions with homogenization temperatures, densities, and salinities of 181-238 °C, 0.81-0.90 g/cm3, and 0.2-1.9 wt.% NaCl eqv., respectively. The ore-forming fluids of the Jiawula deposit are generally characterized by moderate temperature and low salinity and density, and belong to an H2O-NaCl-CO2 ± CH4 system. The δ18Owater values calculated for ore-bearing quartz vary from -13.4‰ to -9.1‰, and the δDV-SMOW values from bulk extraction of fluid inclusion waters vary from -166‰ to -133‰, suggesting that the ore-forming fluids mainly consist of meteoric water with a small amount of magmatic water. The δ34SV-CDT values range from 1.2‰ to 8.4‰. The 206Pb/204Pb

  13. Biogenic gas(?) in fluid inclusions from sandstones in contact with oil-mature coals

    SciTech Connect

    Ohm, S.E.; Karlsen, D.A.

    2007-05-15

    This study was initiated to investigate if coals on the Norwegian offshore continental shelf (NOCS) expel petroleum and in which form. The results revealed that equally isotopically light methane (C{sub 1}) was released from fluid inclusions in sandstones and from adjacent coal (-60.9 to -72.7 parts per thousand). The analyzed samples were collected from cored northern North Sea and mid-Norwegian shelf wells in the depth interval 3924-5095 m. The vitrinite reflectance (R{sub o}) values of the coals range between 0.53 and 1.12%, with most values between 0.8 and 1.0%. The light C{sub 1} isotope values released both from the coals and from the fluid inclusions in the adjacent sandstones suggest that the origin of the gas is the coal, and that no isotope fractionation occurs during release of the gas in nature. Traditional isotope interpretation schemes suggest the C{sub 1} to have a biogenic origin, whereas recently published data also show the possibility for an early mature thermogenic origin. The isotope values represent averages of the total gas released from all the individual disintegrated fluid inclusions in each sample. These did not form simultaneously, but during multiple events potentially covering several million years. We speculate that significant volumes of isotopically light C{sub 1} have been expelled from the analyzed coals over time. The expelled isotopically light C{sub 1}, may mix with mature thermogenically produced gas and skew the overall methane isotope values of gas accumulations toward lighter values, thus explaining the isotopically lighter-than-expected gas accumulations on the NOCS (e.g., Troll, Frigg, and Draugen fields).

  14. Interpretation of fluid inclusions in quartz deformed by weak ductile shearing: Reconstruction of differential stress magnitudes and pre-deformation fluid properties

    NASA Astrophysics Data System (ADS)

    Diamond, Larryn W.; Tarantola, Alexandre

    2015-05-01

    A well developed theoretical framework is available in which paleofluid properties, such as chemical composition and density, can be reconstructed from fluid inclusions in minerals that have undergone no ductile deformation. The present study extends this framework to encompass fluid inclusions hosted by quartz that has undergone weak ductile deformation following fluid entrapment. Recent experiments have shown that such deformation causes inclusions to become dismembered into clusters of irregularly shaped relict inclusions surrounded by planar arrays of tiny, new-formed (neonate) inclusions. Comparison of the experimental samples with a naturally sheared quartz vein from Grimsel Pass, Aar Massif, Central Alps, Switzerland, reveals striking similarities. This strong concordance justifies applying the experimentally derived rules of fluid inclusion behaviour to nature. Thus, planar arrays of dismembered inclusions defining cleavage planes in quartz may be taken as diagnostic of small amounts of intracrystalline strain. Deformed inclusions preserve their pre-deformation concentration ratios of gases to electrolytes, but their H2O contents typically have changed. Morphologically intact inclusions, in contrast, preserve the pre-deformation composition and density of their originally trapped fluid. The orientation of the maximum principal compressive stress (σ1) at the time of shear deformation can be derived from the pole to the cleavage plane within which the dismembered inclusions are aligned. Finally, the density of neonate inclusions is commensurate with the pressure value of σ1 at the temperature and time of deformation. This last rule offers a means to estimate magnitudes of shear stresses from fluid inclusion studies. Application of this new paleopiezometer approach to the Grimsel vein yields a differential stress (σ1-σ3) of ˜ 300 MPa at 390 ± 30 °C during late Miocene NNW-SSE orogenic shortening and regional uplift of the Aar Massif. This differential

  15. Fluctuation-Induced Forces Between Inclusions in a Fluid Membrane Under Tension

    NASA Astrophysics Data System (ADS)

    Lin, Hsiang-Ku; Zandi, Roya; Mohideen, Umar; Pryadko, Leonid P.

    2011-11-01

    We develop an exact method to calculate thermal Casimir forces between inclusions of arbitrary shapes and separation, embedded in a fluid membrane whose fluctuations are governed by the combined action of surface tension, bending modulus, and Gaussian rigidity. Each object’s shape and mechanical properties enter only through a characteristic matrix, a static analog of the scattering matrix. We calculate the Casimir interaction between two elastic disks embedded in a membrane. In particular, we find that at short separations the interaction is strong and independent of surface tension.

  16. Fluctuation-induced forces between inclusions in a fluid membrane under tension.

    PubMed

    Lin, Hsiang-Ku; Zandi, Roya; Mohideen, Umar; Pryadko, Leonid P

    2011-11-25

    We develop an exact method to calculate thermal Casimir forces between inclusions of arbitrary shapes and separation, embedded in a fluid membrane whose fluctuations are governed by the combined action of surface tension, bending modulus, and Gaussian rigidity. Each object's shape and mechanical properties enter only through a characteristic matrix, a static analog of the scattering matrix. We calculate the Casimir interaction between two elastic disks embedded in a membrane. In particular, we find that at short separations the interaction is strong and independent of surface tension.

  17. Modeling on Fluid Flow and Inclusion Motion in Centrifugal Continuous Casting Strands

    NASA Astrophysics Data System (ADS)

    Wang, Qiangqiang; Zhang, Lifeng; Sridhar, Seetharaman

    2016-08-01

    During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment

  18. Quartz precipitation and fluid inclusion characteristics in sub-seafloor hydrothermal systems associated with volcanogenic massive sulfide deposits

    NASA Astrophysics Data System (ADS)

    Steele-MacInnis, Matthew; Han, Liang; Lowell, Robert P.; Rimstidt, J. Donald; Bodnar, Robert J.

    2012-06-01

    Results of a numerical modeling study of quartz dissolution and precipitation in a sub-seafloor hydrothermal system have been used to predict where in the system quartz could be deposited and potentially trap fluid inclusions. The spatial distribution of zones of quartz dissolution and precipitation is complex, owing to the fact that quartz solubility depends on many inter-related factors, including temperature, fluid salinity and fluid immiscibility, and is further complicated by the fact that quartz exhibits both prograde and retrograde solubility behavior, depending on the fluid temperature and salinity. Using the PVTX properties of H2O-NaCl, the petrographic and microthermometric properties of fluid inclusions trapped at various locations within the hydrothermal system have been predicted. Vapor-rich inclusions are trapped as a result of the retrograde temperature-dependence of quartz solubility as the convecting fluid is heated in the vicinity of the magmatic heat source. Coexisting liquid-rich and vapor-rich inclusions are also trapped in this region when quartz precipitates as a result of fluid immiscibility that lowers the overall bulk quartz solubility in the system. Fluid inclusions trapped in the shallow subsurface near the seafloor vents and in the underlying stockwork are liquid-rich with homogenization temperatures of 200-400°C and salinities close to that of seawater. Volcanogenic massive sulfide (VMS) deposits represent the uplifted and partially eroded remnants of fossil submarine hydrothermal systems, and the relationship between fluid-inclusion properties and location within the hydrothermal system described here can be used in exploration for VMS deposits to infer the direction towards potential massive sulfide ore.

  19. The campi flegrei (Italy) geothermal system: A fluid inclusion study of the mofete and San Vito fields

    USGS Publications Warehouse

    de, Vivo B.; Belkin, H.E.; Barbieri, M.; Chelini, W.; Lattanzi, P.; Lima, A.; Tolomeo, L.

    1989-01-01

    A fluid inclusion study of core from the Mofete 1, Mofete 2, Mofete 5, San Vito 1, and San Vito 3 geothermal wells (Campi Flegrei, Campania, Italy) indicates that the hydrothermal minerals were precipitated from aqueous fluids (??CO2) that were moderately saline (3-4 wt.% NaCl equiv.) to hypersaline (> 26 wt.% NaCl equiv.) and at least in part, boiling. Three types of primary fluid inclusions were found in authigenic K-feldspar, quartz, calcite, and epidote: (A) two-phase [liquid (L) + vapor (V)], liquid-rich inclusions with a range of salinity; (B) two-phase (L + V), vaporrich inclusions with low salinity; and (C) three-phase [L + V + crystals (NaCL)], liquid-rich inclusions with hypersalinity. Results of microthermometric and crushing studies are reported for twenty drill core samples taken from the lower portions of the five vertical wells. Data presented for selected core samples reveal a general decrease in porosity and increase in bulk density with increasing depth and temperature. Hydrothermal minerals commonly fill fractures and pore-spaces and define a zonation pattern, similar in all five wells studied, in response to increasing depth (pressure) and temperature. A greenschist facies assemblage, defined by albite + actinolite, gives way to an amphibolite facies, defined by plagioclase (andesine) + hornblende, in the San Vito 1 well at about 380??C. The fluid inclusion salinity values mimic the saline and hypersaline fluids found by drilling. Fluid inclusion V/L homogenization temperatures increase with depth and generally correspond to the extrapolated down-hole temperatures. However, fluid inclusion data for Mofete 5 and mineral assemblage data for San Vito 3, indicate fossil, higher-temperature regimes. A limited 87Sr/86Sr study of leachate (carbonate) and the leached cores shows that for most samples (except San Vito 3) the carbonate deposition has been from slightly 87Sr-enriched fluids and that Sr isotopic exchange has been incomplete. However, San

  20. Fluid inclusion and isotope geochemistry of the Yangla copper deposit, Yunnan, China

    NASA Astrophysics Data System (ADS)

    Yang, Xi-An; Liu, Jia-Jun; Yang, Long-Bo; Han, Si-Yu; Sun, Xiao-Ming; Wang, Huan

    2014-04-01

    The Yangla copper deposit, with Cu reserves of 1.2 Mt, is located between a series of thrust faults in the Jinshajiang-Lancangjiang-Nujiang region, Yunnan, China, and has been mined since 2007. Fluid inclusion trapping conditions ranged from 1.32 to 2.10 kbar at 373-409 °C. Laser Raman spectroscopy confirms that the vapour phase in these inclusions consists of CO2, CH4, N2 and H2O. The gas phases in the inclusions are H2O and CO2, with minor amounts of N2, O2, CO, CH4, C2H2, C2H4, and C2H6. Within the liquid phase, the main cations are Ca2+ and Na+ while the main anions are SO4 2- and Cl-. The oxygen and hydrogen isotope compositions of the ore-forming fluids (-3.05‰ ≤ δ18OH2O ≤ 2.5‰; -100‰ ≤ δD ≤ -120‰) indicate that they were derived from magma and evolved by mixing with local meteoric water. The δ34S values of sulfides range from -4.20‰ to 1.85‰(average on -0.85‰), supporting a magmatic origin. Five molybdenite samples taken from the copper deposit yield a well-constrained 187Re-187Os isochron age of 232.8 ± 2.4 Ma. Given that the Yangla granodiorite formed between 235.6 ± 1.2 Ma and 234.1 ± 1.2 Ma, the Cu metallogenesis is slightly younger than the crystallization age of the parent magma. A tectonic model that combines hydrothermal fluid flow and isotope compositions is proposed to explain the formation of the Yangla copper deposit. At first, westward subduction of the Jinshajiang Oceanic Plate in the Early Permian resulted in the development of a series of thrust faults. This was accompanied by fractional melting beneath the overriding plate, triggering magma ascent and extensive volcanism. The thrust faults, which were then placed under tension during a change in tectonic mode from compression to extension in the Late Triassic, formed favorable pathways for the magmatic ore-forming fluids. These fluids precipitated copper-sulfides to form the Yangla deposit.

  1. Fluid inclusion study of diagenetic mineral phases, Upper Jurassic Smackover Formation, southwest Arkansas and northeast Texas

    SciTech Connect

    O'Hearn, T.C.; Moore, C.H.

    1985-02-01

    Homogenization and final melting temperature data from primary and secondary two-phase fluid inclusions within carbonate and sulfate mineral phases reflect the physical re-equilibration of pre-burial calcites and the precipitation of late diagenetic mineral phases during the burial of the upper Smackover (Upper Jurassic, Oxfordian) lime-grainstones in southwestern Arkansas and northeastern Texas. Homogenization temperatures range from 83.0/sup 0/C to 153.8/sup 0/C (uncorrected for excess ambient formation pressures at time of trapping). Final melting points range from -33.4/sup 0/C to -13.5/sup 0/C. Statistically distinct temperature populations reveal the re-equilibration of pre-burial bladed calcite cements and parallel the subsequent paragenesis during burial of nonfabric-selective dolomite, zoned equant mosaic calcite, anhydrite, celestite, unzoned poikilitic calcite cement, and baroque dolomite cement under conditions of increasing temperature and salinity. Re-equilibration/precipitation began after a minimum depth of burial in the range of 0.95 to 1.75 km. Re-equilibration/precipitation resulted, in part, in response to the original connate meteoric to marine pore water system being mixed with, and subsequently replaced by, basinal brines that migrated into the upper Smackover grainstones from the Louann Salt. Melting temperature data indicate that fluids trapped within the two-phase fluid inclusions are highly saline, varying from 17 to 27 wt. % NaCl. Melting temperature data also indicate that the fluids are CaCl/sub 2/-rich brines with NaCl and probably MgCl/sub 2/ and FeCl/sub 2/ as additional chloride components.

  2. Formation of a magmatic-hydrothermal ore deposit: insights with LA-ICP-MS analysis of fluid inclusions

    PubMed

    Audetat; Gunther; Heinrich

    1998-03-27

    The physical and chemical mechanism of ore precipitation in the Yankee Lode tin deposit (Mole Granite, Australia) was quantified by direct trace-element microanalysis of fluid inclusions. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to measure element concentrations in a series of fluid inclusions representing the fluid before, during, and after the deposition of cassiterite (SnO2). Tin precipitation was driven by mixing of hot magmatic brine with cooler meteoric water. At the same time, a separate magmatic vapor phase selectively transported copper and boron into the liquid mixture.

  3. (Sulfide-oxide-silicate phase equilibria and associated fluid inclusion properties in the Salton Sea geothermal system, California)

    SciTech Connect

    McKibben, M.A.

    1988-06-01

    Our studies involved petrographic, fluid inclusion, geochemical and stable isotopic studies of drillcores and fluids from the Salton Sea geothermal system. Our initial studies revealed the presence of previously-unrecognized evaporitic anhydrite at depth throughout the geothermal system. The high salinity of the Salton Sea geothermal brines previously had been attributed to low-temperature dissolution of surficial evaporitic deposits by meteoric waters. Our microthermometric studies of halite--containing fluid inclusions in the meta-evaporites indicated that the high salinity of the geothermal brines is derived in part from the hydrothermal metamorphism of relatively deeply-buried salt and evaporites. In addition, our research concentrated on mineralized fractures in drillcores.

  4. Formation of a magmatic-hydrothermal ore deposit: insights with LA-ICP-MS analysis of fluid inclusions

    PubMed

    Audetat; Gunther; Heinrich

    1998-03-27

    The physical and chemical mechanism of ore precipitation in the Yankee Lode tin deposit (Mole Granite, Australia) was quantified by direct trace-element microanalysis of fluid inclusions. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to measure element concentrations in a series of fluid inclusions representing the fluid before, during, and after the deposition of cassiterite (SnO2). Tin precipitation was driven by mixing of hot magmatic brine with cooler meteoric water. At the same time, a separate magmatic vapor phase selectively transported copper and boron into the liquid mixture. PMID:9516106

  5. The Importance of Redox Reactions in Fluid Transport Systems in the Earth's Deep Mantle: Evidence from Nano-Inclusions

    NASA Astrophysics Data System (ADS)

    Jacob, D. E.; Wirth, R.; Dobrzhinetskaya, L.

    2014-12-01

    Focused Ion beam assisted TEM studies of inclusions in diamond have opened up a new perspective on the Earth's deep mantle processes. They enabled direct observation of fluids and have shown a large chemical and redox heterogeneity at the submicron scale, which is not observed in micron-sized inclusions. While crustal metamorphic diamonds are generally formed under oxidizing conditions, polycrystalline diamonds from the Earth's mantle and carbonado have inclusion suites reflecting variable, and sometimes extreme, redox conditions. Diamond fluid compositions, however, fall in the same compositional field for worldwide diamond fluids, regardless of their geodynamic environment. They conform with the fluid end-members established by studies on fibrous diamonds, suggesting a universally important role of a limited number of basic ingredients, namely carbonates, silicates, halides and water. Strong redox gradients reflected by the micro-inclusions indicate diamond precipitation via small-scale, ephemeral redox processes driven by the contrasting oxidation states of fluids and their depositional environment. The susceptibility of the melting point of mantle rocks to the presence of even small amounts of volatiles promotes melting simultaneous to diamond precipitation, which is further enhanced by the changing of fluid composition towards higher water activity. This creates a chemically heterogeneous environment, in which diamonds and their inclusions are precipitated via redox-freezing processes.

  6. Relationship between recent cave temperatures and noble gas temperatures derived from fluid inclusions of modern soda straw stalactites

    NASA Astrophysics Data System (ADS)

    Palcsu, Laszlo; Papp, Laszlo; Major, Zoltan; Molnar, Mihaly

    2010-05-01

    Recently, strong effort is devoted to establish a new method to derive palaeotemperatures from noble gas (Ne, Ar, Kr, Xe) concentrations dissolved in fluid inclusions of speleothems [1-2]. It has been already shown that the water content of the speleothems can be determined via the water vapour pressure after the water has been released from the carbonate samples and collected in a cold finger and then heated up to room temperature. Additionally, the noble gas contents can be precisely measured with noble gas mass spectrometers. Based on these noble gas concentration data sets, a so-called noble gas temperature (NGT) can be calculated meaning a temperature at which the noble gases have been dissolved in water. To use these NGT's as a palaeoclimate proxy, one of the main questions is how these noble gas temperatures reflect the prevailing cave temperature in which the carbonate has grown. We studied noble gas significances in recent soda straw stalactites from more than ten Central European caves covering a temperature range of 1 to 14 °C. Kluge et al. (2008) has shown the soda straw stalactites might contain less excess air, hence they are more suitable samples to derive NGT's, because noble gas abundances from large air inclusions can mask the temperature information. The 14C ages of these soda straw dripstones were obtained to be recent or at least Holocene ages. Thus one can assume that the cave temperatures during carbonate formation were as same as at present. We measured the water and noble gas contents of numerous carbonate samples from soda straw stalactites and calculated noble gas temperatures by a precision of 1 °C or better. Comparing these temperatures with cave temperatures we obtained that they agree well within the uncertainty of the noble gas temperature determination. Therefore, we can conclude if diffusion of noble gas isotopes does not play a significant role in the carbonate lattice this new tool helps the palaeoclimate community to gain

  7. Methanethiol abundance in high-temperature hydrothermal fluids from the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Reeves, E.; Seewald, J. S.; Saccocia, P.; van der Meer, M.

    2008-12-01

    The formation of aqueous organic sulfur compounds in hydrothermal systems remains poorly constrained, despite their potential significance in 'prebiotic' chemistry and the origin of life. The simplest - methanethiol (CH3SH) - has been implicated as a critical abiogenic precursor to the establishment of primitive microbial metabolism in early Earth hydrothermal settings. It also represents a readily-utilized substrate for microbial sulfate-reducing communities and a potential intermediate species in abiotic CH4 formation. To assess the abundance of CH3SH and factors regulating its stability under hydrothermal conditions we measured CH3SH concentrations in a suite of hydrothermal fluids collected from the Rainbow, Lucky Strike, TAG and Lost City hydrothermal sites located on the Mid-Atlantic Ridge. Fluids were collected using isobaric gas-tight samplers and analyzed for CH3SH by shipboard purge-and-trap gas chromatography. Measured concentrations at Rainbow (1.2 -- 223nM), Lucky Strike (1.1 -- 26nM), TAG (8.5 -- 11nM) and Lost City (1.6 -- 3.0nM) are all substantially lower than predicted for thermodynamic equilibrium with CO2, H2 and H2S at measured vent conditions. The highest concentrations (91 -- 223nM), however, were observed at Rainbow in intermediate temperature (128 -- 175°C) H2-rich fluids that may have undergone conductive cooling. Increased concentrations with decreasing temperature is consistent with the thermodynamic drive for the formation from CO2, suggesting a possible abiotic origin for CH3SH in some fluids. Substantially lower concentrations in the low temperature fluids at Lost City are consistent with the extremely low levels of CO2 and H2S in these fluids. Other possible sources of CH3SH to vent fluids must be considered, however, and include thermal alteration of biomass present in low-temperature environments and microbial consortia that produce CH3SH as a byproduct of anaerobic methane oxidation. Current models for the emergence of primordial

  8. Sultan Mountain mine, western San Juan Mountains, Colorado: A fluid inclusion and stable isotope study

    SciTech Connect

    Musgrave, J.A. ); Thompson, T.B. . Dept. of Earth Resources)

    1991-01-01

    The Sultan Mountain (SM) mine, in the western San Juan Mountains of Colorado, has produced Cu-Pb-Zn-Ag-Au ores from the mid-1870s until the 1950s. Production was from veins filling faults and fissures along the southern margin of the Silverton caldera. The principal host rock to the veins is a quartz monzonite stock. Five periods of hypogene mineralization have been recognized: (1) early quartz-pyrite; (2) quartz-pyrite; (3) rhodochrosite-siderite; (4) main ore-stage chalcopyrite, tetrahedrite, galena, sphalerite, and gold; and (5) quartz-fluorite. Evidence of open-space filling (banding, crustification, vugs) is widespread. Heating studies of fluid inclusions in quartz, rhodochrosite-siderite, sphalerite, and fluorite indicate temperatures were approximately 200 C for stages 1 to 4 and 186 C for stage 5. Stages 1, 2, and 4 show evidence of boiling. Crushing studies indicate that high-pressure gas, probably CO[sub 2], is present in the fluid inclusions. Freezing point depression estimates of salinity, corrected for CO[sub 2], indicate a range of 13.6 to 1.3 wt percent NaCl equiv. These data together with P-V-T data for saline solutions and P[sub CO[sub 2

  9. Integrated mineralogical and fluid inclusion study of the Coso geothermal systems, California

    SciTech Connect

    Lutz, Susan J.; Moore, Joseph N.; Copp, John F.

    1996-01-24

    Coso is one of several high-temperature geothermal systems on the margins of the Basin and Range province that is associated with recent volcanic activity. This system, which is developed entirely in fractured granitic and metamorphic rocks, consists of a well-defined thermal plume that originates in the southern part of the field and then flows upward and laterally to the north. Fluid inclusion homogenization temperatures and salinities demonstrate that cool, low salinity ground waters were present when the thermal plume was emplaced. Dilution of the thermal waters occurred above and below the plume producing strong gradients in their compositions. In response to heating and mixing, clays and carbonate minerals precipitated, sealing the fractures along the margins of the reservoir and strongly influencing its geometry. The alteration mineralogy varies systematically with depth and temperature. Based on the clay mineralogy, three zones can be recognized: the smectite zone, the illite-smectite zone, and the illite zone. The smectite zone thickens from the north to south and is characterized by smectite, kaolin, stilbite and a variety of carbonate minerals. The illite-smectite zone contains mixed-layer clays and also thickens to the south. The deepest zone (the illite zone) contains illite, chlorite, epidote, and wairakite. Quartz and calcite veins occur in all three zones. Comparison of mineral and fluid inclusion based temperatures demonstrates that cooling has occurred along the margins of the thermal system but that the interior of the system is still undergoing heating.

  10. Late Eocene to early Oligocene quantitative paleotemperature record: evidence from continental halite fluid inclusions.

    PubMed

    Zhao, Yan-jun; Zhang, Hua; Liu, Cheng-lin; Liu, Bao-kun; Ma, Li-chun; Wang, Li-cheng

    2014-01-01

    Climate changes within Cenozoic extreme climate events such as the Paleocene-Eocene Thermal Maximum and the First Oligocene Glacial provide good opportunities to estimate the global climate trends in our present and future life. However, quantitative paleotemperatures data for Cenozoic climatic reconstruction are still lacking, hindering a better understanding of the past and future climate conditions. In this contribution, quantitative paleotemperatures were determined by fluid inclusion homogenization temperature (Th) data from continental halite of the first member of the Shahejie Formation (SF1; probably late Eocene to early Oligocene) in Bohai Bay Basin, North China. The primary textures of the SF1 halite typified by cumulate and chevron halite suggest halite deposited in a shallow saline water and halite Th can serve as an temperature proxy. In total, one-hundred-twenty-one Th data from primary and single-phase aqueous fluid inclusions with different depths were acquired by the cooling nucleation method. The results show that all Th range from 17.7°C to 50.7°C,with the maximum homogenization temperatures (ThMAX) of 50.5°C at the depth of 3028.04 m and 50.7°C at 3188.61 m, respectively. Both the ThMAX presented here are significantly higher than the highest temperature recorded in this region since 1954 and agree with global temperature models for the year 2100 predicted by the Intergovernmental Panel on Climate Change. PMID:25047483

  11. Late Eocene to early Oligocene quantitative paleotemperature record: evidence from continental halite fluid inclusions.

    PubMed

    Zhao, Yan-jun; Zhang, Hua; Liu, Cheng-lin; Liu, Bao-kun; Ma, Li-chun; Wang, Li-cheng

    2014-01-01

    Climate changes within Cenozoic extreme climate events such as the Paleocene-Eocene Thermal Maximum and the First Oligocene Glacial provide good opportunities to estimate the global climate trends in our present and future life. However, quantitative paleotemperatures data for Cenozoic climatic reconstruction are still lacking, hindering a better understanding of the past and future climate conditions. In this contribution, quantitative paleotemperatures were determined by fluid inclusion homogenization temperature (Th) data from continental halite of the first member of the Shahejie Formation (SF1; probably late Eocene to early Oligocene) in Bohai Bay Basin, North China. The primary textures of the SF1 halite typified by cumulate and chevron halite suggest halite deposited in a shallow saline water and halite Th can serve as an temperature proxy. In total, one-hundred-twenty-one Th data from primary and single-phase aqueous fluid inclusions with different depths were acquired by the cooling nucleation method. The results show that all Th range from 17.7°C to 50.7°C,with the maximum homogenization temperatures (ThMAX) of 50.5°C at the depth of 3028.04 m and 50.7°C at 3188.61 m, respectively. Both the ThMAX presented here are significantly higher than the highest temperature recorded in this region since 1954 and agree with global temperature models for the year 2100 predicted by the Intergovernmental Panel on Climate Change.

  12. Late Eocene to early Oligocene quantitative paleotemperature record: Evidence from continental halite fluid inclusions

    PubMed Central

    Zhao, Yan-jun; Zhang, Hua; Liu, Cheng-lin; Liu, Bao-kun; Ma, Li-chun; Wang, Li-cheng

    2014-01-01

    Climate changes within Cenozoic extreme climate events such as the Paleocene–Eocene Thermal Maximum and the First Oligocene Glacial provide good opportunities to estimate the global climate trends in our present and future life. However, quantitative paleotemperatures data for Cenozoic climatic reconstruction are still lacking, hindering a better understanding of the past and future climate conditions. In this contribution, quantitative paleotemperatures were determined by fluid inclusion homogenization temperature (Th) data from continental halite of the first member of the Shahejie Formation (SF1; probably late Eocene to early Oligocene) in Bohai Bay Basin, North China. The primary textures of the SF1 halite typified by cumulate and chevron halite suggest halite deposited in a shallow saline water and halite Th can serve as an temperature proxy. In total, one-hundred-twenty-one Th data from primary and single-phase aqueous fluid inclusions with different depths were acquired by the cooling nucleation method. The results show that all Th range from 17.7°C to 50.7°C,with the maximum homogenization temperatures (ThMAX) of 50.5°C at the depth of 3028.04 m and 50.7°C at 3188.61 m, respectively. Both the ThMAX presented here are significantly higher than the highest temperature recorded in this region since 1954and agree with global temperature models for the year 2100 predicted by the Intergovernmental Panel on Climate Change. PMID:25047483

  13. A XANES study of Cu speciation in high-temperature brines using synthetic fluid inclusions

    SciTech Connect

    Berry, Andrew J.; Hack, Alistair C.; Mavrogenes, John A.; Newville, Matthew; Sutton, Stephen R.

    2010-12-03

    Cu K-edge X-ray absorption near edge structure (XANES) spectra were recorded from individual synthetic brine fluid inclusions as a function of temperature up to 500 C. The inclusions serve as sample cells for high-temperature spectroscopic studies of aqueous Cu-Cl speciation. Cu{sup +} and Cu{sup 2+} can both be identified from characteristic pre-edge features. Mixed oxidation states can be deconvoluted using linear combinations of Cu{sup +} and Cu{sup 2+} spectra. This work illustrates how complex Cu XANES spectra can be interpreted successfully. Cu{sup 2+} is the stable oxidation state in solution at room temperature and Cu{sup +} at high temperatures. The change in oxidation state with temperature was completely reversible. Cu{sup +} was found to occur exclusively as the linear species [CuCl{sub 2}]{sup -} in solutions containing KCl with Cu:Cl ratios up to 1:6. In the absence of K{sup +}, there is evidence for higher order coordination of Cu{sup +}, in particular the tetrahedral complex [CuCl{sub 4}]{sup 3-}. The importance of such complexes in natural ore-forming fluids is yet to be determined, but may explain the vapor-phase partitioning of Cu as a Cl complex from a Cl-rich brine.

  14. Acidophilic halophilic microorganisms in fluid inclusions in halite from Lake Magic, Western Australia.

    PubMed

    Conner, Amber J; Benison, Kathleen C

    2013-09-01

    Lake Magic is one of the most extreme of hundreds of ephemeral acid-saline lakes in southern Western Australia. It has pH as low as 1.7, salinity as high as 32% total dissolved solids, temperatures ranging from 0°C to 50°C, and an unusually complex aqueous composition. Optical petrography, UV-vis petrography, and laser Raman spectrometry were used to detect microorganisms and organic compounds within primary fluid inclusions in modern bedded halite from Lake Magic. Rare prokaryotes appear as 1-3 μm, bright cocci that fluoresce green with UV-vis illumination. Dimpled, 5-7 μm yellow spherules that fluoresce blue with UV-vis illumination are interpreted as Dunaliella algae. Yellow-orange beta-carotene crystals, globules, and coatings are characterized by orange-red fluorescence and three distinct Raman peaks. Because acid saline lakes are good Mars analogues, the documentation of prokaryotes, eukaryotes, and organic compounds preserved in the halite here has implications for the search for life on Mars. Missions to Mars should incorporate such in situ optical and chemical examination of martian evaporites for possible microorganisms and/or organic compounds in fluid inclusions. PMID:23971647

  15. Acidophilic halophilic microorganisms in fluid inclusions in halite from Lake Magic, Western Australia.

    PubMed

    Conner, Amber J; Benison, Kathleen C

    2013-09-01

    Lake Magic is one of the most extreme of hundreds of ephemeral acid-saline lakes in southern Western Australia. It has pH as low as 1.7, salinity as high as 32% total dissolved solids, temperatures ranging from 0°C to 50°C, and an unusually complex aqueous composition. Optical petrography, UV-vis petrography, and laser Raman spectrometry were used to detect microorganisms and organic compounds within primary fluid inclusions in modern bedded halite from Lake Magic. Rare prokaryotes appear as 1-3 μm, bright cocci that fluoresce green with UV-vis illumination. Dimpled, 5-7 μm yellow spherules that fluoresce blue with UV-vis illumination are interpreted as Dunaliella algae. Yellow-orange beta-carotene crystals, globules, and coatings are characterized by orange-red fluorescence and three distinct Raman peaks. Because acid saline lakes are good Mars analogues, the documentation of prokaryotes, eukaryotes, and organic compounds preserved in the halite here has implications for the search for life on Mars. Missions to Mars should incorporate such in situ optical and chemical examination of martian evaporites for possible microorganisms and/or organic compounds in fluid inclusions.

  16. Homogenization Temperature Measurements in Hydrothermal Diamond-Anvil Cell for Melt and Fluid Inclusions from the Jiajika Pegmatite Deposit, China

    NASA Astrophysics Data System (ADS)

    Li, J.; Chou, I.; Yuan, S.; Burruss, R. C.

    2009-12-01

    We measured the total homogenization temperatures (Th) of volatile-rich melt and fluid inclusions under elevated external pressures in a hydrothermal diamond-anvil cell (HDAC) to understand fluid evolution in the Jiajika pegmatite deposit in China, the largest spodumene deposit in Asia. Three types of inclusions were investigated: 1. CH4-H2O (~10 vol. %) bearing aluminosilicate melt inclusions hosted in quartz from granite; 2. CO2-NaCl-H2O (~80 vol. %) inclusions with daughter minerals mainly hosted in spodumene from pegmatite dikes; and 3. CO2-NaCl-H2O inclusions mainly hosted in quartz from pegmatite dikes. During normal microthermometric measurements at atmospheric pressure, most of these inclusions decrepitated at ~300°C. Therefore, we extended the method of Schmidt et al. (1998, Am. Mineral. 83, 995) and Darling and Bassett (2002, Am. Mineral., 87, 67) to melt inclusions in HDAC and conducted long-duration experiments with type 1 and 2 inclusions at one kbar Ar pressure in cold-seal pressure vessels (CSPV) as described by Thomas et al. (2006, Chapter 9 in Mineralogical Association of Canada Short Course, 36, 189). Results in both HDAC and CSPV experiments showed that Th's of type 1 and 2 inclusions were between 600 and 700 °C and between 500 and 700 °C, respectively. In HDAC experiments for type 1 inclusions, daughter minerals melted and coexisted with the fluid phase before total homogenization; however, in type 2 inclusions, daughter minerals dissolved completely in the CO2-NaCl-H2O solution at Th. Results obtained for type 3 inclusions showed that the CO2-rich and CO2-poor inclusions homogenized to liquid CO2 and aqueous phases at 260 - 570 and 240 - 350°C, respectively. Also, Th’s decrease linearly as the external pressure increases; the reduction of Th was ~1.5 °C/kbar, which is similar to ~1.2 °C/kbar reported by Darling and Bassett (ibid.) for the same type of natural fluid inclusions, but is much less than ~4.6 °C/kbar reported by Schmidt et

  17. Laser microprobe analyses of Cl, Br, I, and K in fluid inclusions: Implications for sources of salinity in some ancient hydrothermal fluids

    USGS Publications Warehouse

    Böhlke, J.K.; Irwin, J.J.

    1992-01-01

    The relative concentrations of Cl, Br, I, and K in fluid inclusions in hydrothermal minerals were measured by laser microprobe noble gas mass spectrometry on irradiated samples containing 10-10 to 10-8 L of fluid. Distinctive halogen signatures indicate contrasting sources of fluid salinity in fluid inclusions from representative "magmatic" (St. Austell), "metamorphic" (Alleghany), and "geothermal" (Creede, Salton Sea) aqueous systems. Br/Cl mol ratios are lowest at Salton Sea (0.27-0.33 ?? 10-3), where high salinities are largely due to halite dissolution; intermediate at St. Austell (0.85 ?? 10-3), possibly representative of magmatic volatiles; and highest (near that of seawater) at Creede (1.5-2.1 ?? 10-3) and Alleghany (1.2-2.4 ?? 10-3), where dissolved halogens probably were leached from volcanic and (or) nonevaporitic sedimentary rocks. I C1 mol ratios are lowest (near that of seawater) at Creede (1-14 ?? 10-6), possibly because organisms scavenged I during low temperature recharge; intermediate at Salton Sea (24-26 ?? 10-6) and St. Austell (81?? 10-6); and highest at Alleghany (320-940 ?? 10-6), probably because the fluids interacted with organic-rich sediments at high temperatures before being trapped. K Cl mol ratios indicate disequilibrium with respect to hypothetical feldspathic alkali-Al-silicate mineral buffers at fluid inclusion trapping temperatures at Creede, and large contributions of (Na, K)-bicarbonate to total fluid ionic strength at Alleghany. Significant variations in Cl/Br/I/K ratios among different fluid inclusion types are correlated with previously documented mineralization stages at Creede, and with the apparent oxidation state of dissolved carbon at Alleghany. The new data indicate that Cl/ Br/I ratios in hydrothermal fluid inclusions vary by several orders of magnitude, as they do in modern surface and ground waters. This study demonstrates that halogen signatures of fluid inclusions determined by microanalysis yield important

  18. Effects of glacial ice on subsurface temperatures of hydrothermal systems in Yellowstone National Park, Wyoming: Fluid-inclusion evidence

    SciTech Connect

    Bargar, K.E.; Fournier, R.O. )

    1988-12-01

    Hydrothermal quartz and fluorite crystals containing liquid-rich fluid inclusions (coexisting vapor-rich fluid inclusions were not observed) were found in drill cores from eight relatively shallow research holes drilled by the US Geological Survey in and near major geyser basins of Yellowstone National Park. Homogenization temperatures (T{sub h}) for mostly secondary fluid inclusions show variations in temperature that have occurred at give depths since precipitation of the host minerals. Within major hydrothermal upflow zones, fluid-inclusion T{sub h} values all were found to be equal to or higher (commonly 20-50 C and up to 155 C higher) than present temperatures at the depths sampled. During periods when thick glacial ice covered the Yellowstone National Park region, pore-fluid pressures in the underlying rock were increased in proportion to the weight of the overlying column of ice. Accordingly, theoretical reference boiling-point curves that reflect the maximum temperature attainable in a hot-water geothermal system at a given depth were elevated, and temperatures within zones of major hydrothermal upflow (drill holes Y-2, Y-3, Y-6, Y-11, Y-13, and upper part of Y-5) increased. The thicknesses of ice required to elevate boiling-point curves sufficiently to account for the observed fluid-inclusion T{sub h} values are within the ranges estimated by glacial geologic studies. At the margins of major hydrothermal upflow zones (drill holes Y-4 and Y-9), fluid-inclusion T{sub h} values at given depths range from 57 C lower to about the same as the current temperature measurements because of a previous decrease in the rate of discharge of warm water and/or an increase in the rate of recharge of cold water into the hydrothermal system.

  19. Sapphirine and fluid inclusions in Tel Thanoun mantle xenoliths,Syria

    NASA Astrophysics Data System (ADS)

    Bilal, Ahmad

    2016-04-01

    Volcanoes along the Syrian rift, which extend a distance of about 1000 km, brought to the surface mantle xenoliths within erupted basalts, during multiples periods of volcanic activity. Xenoliths in early Cretaceous volcanoes originate in the garnet peridotite field of the subcontinental mantle, whereas those in recent Cenozoic volcanoes, the prime object of this study, are issued from shallower levels (spinel peridotite field). The recent discovery of sapphirine-bearing websterite in Tel Thanoun, a small volcanic diatreme inside the larger Quaternary volcanic field (Djebel Al Arab), allows us to estimate the P-T evolution and fluid-rock interaction at the volcanic source. Harzburgites and lherzolites are equilibrated at a temperature of about 1000 °C at a depth of 35-40 km. Sapphirine appears to have formed during cooling, at depth at a temperature of about 900 °C, at a time where spinel exsolution occurred in harzburgite and lherzolite pyroxenes. This occurred in the presence of a high-density pure CO2 fluid phase, still present in primary fluid inclusions. The highly-aluminous sapphirine-bearing protolith might be former garnet websterite (possibly uplifted during cretaceous magmatism), which resided and cooled in the spinel peridotite stability field, and was then dragged and brought to the surface by quaternary basalts.

  20. Role of evaporitic sulfates in iron skarn mineralization: a fluid inclusion and sulfur isotope study from the Xishimen deposit, Handan-Xingtai district, North China Craton

    NASA Astrophysics Data System (ADS)

    Wen, Guang; Bi, Shi-Jian; Li, Jian-Wei

    2016-08-01

    The Xishimen iron skarn deposit in the Handan-Xingtai district, North China Craton, contains 256 Mt @ 43 % Fe (up to 65 %). The mineralization is dominated by massive magnetite ore along the contact zone between the early Cretaceous Xishimen diorite stock and middle Ordovician dolomite and dolomitic limestones with numerous intercalations of evaporitic beds. Minor lenticular magnetite-dominated bodies also occur in the carbonate rocks proximal to the diorite stock. Hydrothermal alteration is characterized by extensive albitization within the diorite stock and extreme development of magnesian skarn along the contact zone consisting of diopside, forsterite, serpentine, tremolite, phlogopite, and talc. Magmatic quartz and amphibole from the diorite and hydrothermal diopside from the skarns contain abundant primary or pseudosecondary fluid inclusions, most of which have multiple daughter minerals dominated by halite, sylvite, and opaque phases. Scanning electron microscopy (SEM) and laser Raman spectrometry confirm that pyrrhotite is the predominant opaque phase in most fluid inclusions, in both the magmatic and skarn minerals. These fluid inclusions have total homogenization temperatures of 416-620 °C and calculated salinities of 42.4-74.5 wt% NaCl equiv. The fluid inclusion data thus document a high-temperature, high-salinity, ferrous iron-rich, reducing fluid exsolved from a cooling magma likely represented by the Xishimen diorite stock. Pyrite from the iron ore has δ34S values ranging from 14.0 to 18.6 ‰, which are significantly higher than typical magmatic values (δ34S = 0 ± 5 ‰). The sulfur isotope data thus indicate an external source for the sulfur, most likely from the evaporitic beds in the Ordovician carbonate sequences that have δ34S values of 24 to 29 ‰. We suggest that sulfates from the evaporitic beds have played a critically important role by oxidizing ferrous iron in the magmatic-hydrothermal fluid, leading to precipitation of massive

  1. Formation of magnesite and siderite deposits in the Southern Urals—evidence of inclusion fluid chemistry

    NASA Astrophysics Data System (ADS)

    Prochaska, W.; Krupenin, M.

    2013-02-01

    World-class deposits of magnesite and siderite occur in Riphean strata of the Southern Urals, Russia. Field evidence, inclusion fluid chemistry, and stable isotope data presented in this study clearly proof that the replacement and precipitation processes leading to the formation of the epigenetic dolomite, magnesite and hydrothermal siderite were genetically related to evaporitic fluids affecting already lithified rocks. There is, however, a systematic succession of events leading to the formation of magnesite in a first stage. After burial and diagenesis the same brines were modified to hot and reducing hydrothermal fluids and were the source for the formation of hydrothermal siderite. The magnesites of the Satka Formation as well as the magnesites and the siderites of the Bakal Formation exhibit low Na/Br (106 to 222) and Cl/Br (162 to 280) ratios plotting on the seawater evaporation trend, indicating that the fluids acquired their salinity by evaporation processes of seawater. Temperature calculations based on cation exchange thermometers indicate a formation temperature of the magnesites of ~ 130 °C. Considering the fractionation at this temperature stable isotope evidence shows that the magnesite forming brines had δ18OSMOW values of ~ +1 ‰ thus indicating a seawater origin of the original fluid. Furthermore it proves that these fluids were not yet affected by appreciable fluid-rock interaction, which again implies magnesite formation in relatively high crustal levels. In contrast to the magnesites, the siderite mineralization was caused by hydrothermal fluids that underwent more intense reactions with their host rocks in deeper crustal levels compared to the magnesite. The values of 87Sr /86Sr in the siderites are substantially higher compared to the host rock slates. They also exceed the 87Sr /86Sr ratios of the magnesites and the host rock limestones indicating these slates as the source of iron as a consequence of water-rock interaction. The siderites

  2. Extremely halophilic archaea from ancient salt sediments and their possible survival in halite fluid inclusions

    NASA Astrophysics Data System (ADS)

    Stan-Lotter, H.; Fendrihan, S.; Gerbl, F. W.; Dornmayr-Pfaffenhuemer, M.; Frethem, C.

    2008-09-01

    Halophilic archaebacteria (haloarchaea) thrive in environments with salt concentrations approaching saturation, such as natural brines, marine solar salterns and alkaline salt lakes; they have also been isolated from ancient subsurface salt sediments of great geological age (195-280 million years) and some of those strains were described as novel species (1). The cells survived perhaps while being enclosed within small fluid inclusions in the halite. The characterization of subsurface microbial life is of astrobiological relevance since extraterrestrial halite has been detected and since microbial life on Mars, if existent, may have retreated into the subsurface. We attempted to simulate the embedding process of extremely halophilic archaea and to analyse any cellular changes which might occur. When enclosing haloarchaea in laboratory grown halite, cells accumulated preferentially in fluid inclusions, as could be demonstrated by pre-staining with fluorescent dyes. With increased time of embedding, rod-shaped cells of Halobacterium salinarum strains were found to assume roundish morphologies. Upon dissolution of the salt crystals, these spheres were stable and viable for months when kept in buffers containing 4 M NaCl. Scanning electron microscopy (SEM) following fixation with glutaraldehyde suggested a potentially gradual transformation from rods to spheres. This notion was supported by fluorescence microscopy of Halobacterium cells, following embedding in halite and staining with SYTO 9. One-dimensional protein patterns of rods and spheres, following SDS polyacrylamide gel electrophoresis, were similar except that the S-layer protein appeared reduced by about 15 - 20 % in spheres. The reddish-orange pigmentation of spheres was much lighter compared to that of rod-shaped cells, suggesting lowered concentrations of carotenoids; this was confirmed by extraction and spectrometry of pigments. The data suggested that Halobacterium cells are capable of forming specific

  3. Variation in Volatile and Ore Metal Abundances Along the New Zealand Volcanic Arc as Recorded by Minerals and Melt Inclusions

    NASA Astrophysics Data System (ADS)

    Rowe, M. C.; Iveson, A. A.; Norling, B.; Chambefort, I. S.; Webster, J. D.

    2015-12-01

    Volatile and ore metals within magmas record a wide variety of magmatic processes in the Earth's shallow upper crust. These elements have previously been linked to volatile degassing or exsolution and such processes as eruption triggering and the formation of magmatic ore deposits. However, it is unknown why different volcanoes, or different eruptions of the same volcano, record such wide-ranging geochemical behaviour. More fundamental questions related to the source of these metals also remain unanswered, such as what role (if any) does subduction play in controlling metal fluctuations. In an effort to ascertain the sources of volatile and ore metal variation in intermediate-silicic magmas, this study attempts to take a more comprehensive look at the causes of volatile and ore metal variation in arc magmas as a function of composition and location within a single arc system. This study focuses on the New Zealand arc system, stretching from Mt Taranaki to White Island, examining volatile and trace metals (including Li, Cu, As, Mo, Sb, Sn, W, and Tl) from varying phenocryst phases and melt inclusions. Melt inclusion compositions range from basaltic (51 wt% SiO2) to high-Si rhyolite (81 wt% SiO2), however are predominantly andesitic to dacitic. Sulfur and Cl melt compositions are also highly variable, with concentrations from below detection limit up to ~2000 ppm S and 5300 ppm Cl. Trace metal abundances were determined for all major phenocryst phases, including plagioclase, clinopyroxene, orthopyroxene, and amphibole and biotite where available. Comparing trace metal abundances of phenocrysts and inclusions to both glass and crystal major element/volatile compositions allows for a systematic comparison of volcanoes along the arc. Lithium and Cu are the only two trace metals above detection limit in all analysed phases, however, Cu variations are highly variable compared to other ore metals. New experimental crystallisation runs with hydrous dacite also allow us to

  4. A fluid inclusion study of fluid pressure and salinity variations in the footwall of the rector branch thrust, North Carolina, U.S.A.

    NASA Astrophysics Data System (ADS)

    O'Hara, Kieran; Haak, Amy

    1992-05-01

    Last melting and homogenization temperatures of fluid inclusions from plastically deformed bedding-parallel quartz veins in the footwall of the Rector Branch thrust, North Carolina, were studied as a function of distance from the thrust. Fluid inclusions and microstructures in mylonitic rocks within the thrust zone were also examined. Fluid inclusions in quartz veins which display evidence for intracrystalline plasticity (e.g. subgrain polygonization) occur along subgrain boundaries and have higher homogenization temperatures ( Tn) and a wider range (120-320°C) compared to less deformed samples. Maximum Th values, which approach the temperature of deformation (300 ± 20° C), apparently reflect leakage of inclusions along subgrain boundaries. Minimum Th values (120-160°C), on the other hand, record near lithostatic conditions (2.6 kb) at 300°C. Maximum last melting temperatures ( Tm) increase from -20 to -4°C with decreasing distance to the thrust, corresponding to a decrease in salinity of the fluid from 23 to 3 wt% (NaCl equivalent). The decrease in salinity towards the fault is interpreted as due to infiltration of the fault at depth (to approximately 10 km) by surface derived waters during periods of fault zone dilatancy. Inclusions along healed microcracks in quartz from the fault zone display higher salinity (17-26 wt% NaCl equiv.) and are interpreted to reflect enhanced fluid-rock interaction in the fault zone due to hydration reactions. The fluid pressure and salinity variations are consistent with a combined dilatancy-hydraulic fracturing model for the Rector Branch thrust. Previously documented bulk rock volume losses for this fault zone are inferred to have been produced by the fluxing of the fault zone with undersaturated surface derived fluids.

  5. Pressure-temperature-fluid constraints for the Emmaville-Torrington emerald deposit, New South Wales, Australia: Fluid inclusion and stable isotope studies

    NASA Astrophysics Data System (ADS)

    Loughrey, Lara; Marshall, Dan; Jones, Peter; Millsteed, Paul; Main, Arthur

    2012-06-01

    The Emmaville-Torrington emeralds were first discovered in 1890 in quartz veins hosted within a Permian metasedimentary sequence, consisting of meta-siltstones, slates and quartzites intruded by pegmatite and aplite veins from the Moule Granite. The emerald deposit genesis is consistent with a typical granite-related emerald vein system. Emeralds from these veins display colour zonation alternating between emerald and clear beryl. Two fluid inclusion types are identified: three-phase (brine+vapour+halite) and two-phase (vapour+liquid) fluid inclusions. Fluid inclusion studies indicate the emeralds were precipitated from saline fluids ranging from approximately 33 mass percent NaCl equivalent. Formational pressures and temperatures of 350 to 400 °C and approximately 150 to 250 bars were derived from fluid inclusion and petrographic studies that also indicate emerald and beryl precipitation respectively from the liquid and vapour portions of a two-phase (boiling) system. The distinct colour zonations observed in the emerald from these deposits is the first recorded emerald locality which shows evidence of colour variation as a function of boiling. The primary three-phase and primary two-phase FITs are consistent with alternating chromium-rich `striped' colour banding. Alternating emerald zones with colourless beryl are due to chromium and vanadium partitioning in the liquid portion of the boiling system. The chemical variations observed at Emmaville-Torrington are similar to other colour zoned emeralds from other localities worldwide likely precipitated from a boiling system as well.

  6. Metamorphic fluids and uplift-erosion history of a portion of the Kapuskasing structural zone, Ontario, as deduced from fluid inclusions

    NASA Technical Reports Server (NTRS)

    Rudnick, R. L.; Ashwal, L. D.; Henry, D. J.

    1983-01-01

    Fluid inclusions can be used to determine the compositional evolution of fluids present in high grade metamorphic rocks (Touret, 1979) along with the general P-T path followed by the rocks during uplift and erosion (Hollister et al., 1979). In this context, samples of high grade gneisses from the Kapuskasing structural zone (KSZ, Fig. 1) of eastern Ontario were studied in an attempt to define the composition of syn- and post-metamorphic fluids and help constrain the uplift and erosion history of the KSZ. Recent work by Percival (1980), Percival and Card (1983) and Percival and Krogh (1983) shows that the KSZ represents lower crustal granulites that form the lower portion of an oblique cross section through the Archean crust, which was up faulted along a northeast striking thrust fault. The present fluid inclusion study places constraints upon the P-T path which the KSZ followed during uplift and erosion.

  7. Source and evolution of ore-forming hydrothermal fluids in the northern Iberian Pyrite Belt massive sulphide deposits (SW Spain): evidence from fluid inclusions and stable isotopes

    NASA Astrophysics Data System (ADS)

    Sánchez-España, Javier; Velasco, Francisco; Boyce, Adrian J.; Fallick, Anthony E.

    2003-08-01

    A fluid inclusion and stable isotopic study has been undertaken on some massive sulphide deposits (Aguas Teñidas Este, Concepción, San Miguel, San Telmo and Cueva de la Mora) located in the northern Iberian Pyrite Belt. The isotopic analyses were mainly performed on quartz, chlorite, carbonate and whole rock samples from the stockworks and altered footwall zones of the deposits, and also on some fluid inclusion waters. Homogenization temperatures of fluid inclusions in quartz mostly range from 120 to 280 °C. Salinity of most fluid inclusions ranges from 2 to 14 wt% NaCl equiv. A few cases with Th=80-110 °C and salinity of 16-24 wt% NaCl equiv., have been also recognized. In addition, fluid inclusions from the Soloviejo Mn-Fe-jaspers (160-190 °C and ≈6 wt% NaCl equiv.) and some Late to Post-Hercynian quartz veins (130-270 °C and ≈4 wt% NaCl equiv.) were also studied. Isotopic results indicate that fluids in equilibrium with measured quartz (δ18Ofluid ≈-2 to 4‰), chlorites (δ18Ofluid ≈8-14‰, δDfluid ≈-45 to -27‰), whole rocks (δ18Ofluid ≈4-7‰, δDfluid ≈-15 to -10‰), and carbonates (δ18Oankerite ≈14.5-16‰, δ13Cfluid =-11 to -5‰) evolved isotopically during the lifetime of the hydrothermal systems, following a waxing/waning cycle at different temperatures and water/rock ratios. The results (fluid inclusions, δ18O, δD and δ13C values) point to a highly evolved seawater, along with a variable (but significant) contribution of other fluid reservoirs such as magmatic and/or deep metamorphic waters, as the most probable sources for the ore-forming fluids. These fluids interacted with the underlying volcanic and sedimentary rocks during convective circulation through the upper crust.

  8. Design of two crushing devices for release of the fluid inclusion volatiles

    NASA Astrophysics Data System (ADS)

    Dublyansky, Yuri

    2012-06-01

    Two crushing cells have been described for the release of volatiles from fluid inclusions in minerals in vacuum, static gas, and gas-flow applications. To minimize the adsorption of released volatiles on the freshly created mineral surfaces, both devices employed heated crushing. In the MTSN (Museo Tridentine di Scienze Naturali) crusher, samples were disintegrated by a piston driven by an induction coil. For efficient crushing, the electromagnet operated in dynamic impulse mode. In the LFU (Leopold-Franzens-Universität) crusher, the sample was disintegrated through the combined action of compression (manually operated hydraulic ram) and attrition. Crushers are able to be used in off-line and on-line modes, in gas chromatographic and mass spectrometric analyses.

  9. Brillouin spectroscopy of fluid inclusions proposed as a paleothermometer for subsurface rocks.

    PubMed

    El Mekki-Azouzi, Mouna; Tripathi, Chandra Shekhar Pati; Pallares, Gaël; Gardien, Véronique; Caupin, Frédéric

    2015-01-01

    As widespread, continuous instrumental Earth surface air temperature records are available only for the last hundred fifty years, indirect reconstructions of past temperatures are obtained by analyzing "proxies". Fluid inclusions (FIs) present in virtually all rock minerals including exogenous rocks are routinely used to constrain formation temperature of crystals. The method relies on the presence of a vapour bubble in the FI. However, measurements are sometimes biased by surface tension effects. They are even impossible when the bubble is absent (monophasic FI) for kinetic or thermodynamic reasons. These limitations are common for surface or subsurface rocks. Here we use FIs in hydrothermal or geodic quartz crystals to demonstrate the potential of Brillouin spectroscopy in determining the formation temperature of monophasic FIs without the need for a bubble. Hence, this novel method offers a promising way to overcome the above limitations. PMID:26316328

  10. Chemical and textural characteristics of multistage fluid inclusions with high Li/B ratio found from the Sanbagawa belt.

    NASA Astrophysics Data System (ADS)

    Yoshida, K.; Hirajima, T.

    2012-04-01

    Recent studies invoked that the variation of peculiar fluid soluble light elements, such as Li, B and Cl, are capable of suggesting generation depths of fluid released in subduction zones (e.g., Scambelluri et al., 2004; Bebout et al., 2007; Marschall et al., 2009). Crush-leached fluids extracted from quartz veins intercalated with metabasites of the Sanbagawa metamorphic belt show high Li and B concentrations, whose Li/B ratios show a positive correlation with metamorphic grade of the host rocks, i.e., from 0.02 for pumpellyite-actinolite facies to 0.27 for eclogite facies (Sengen et al., 2009). Furthermore, crush-leached fluids extracted from quartz veins intercalated with metasediments in proximal to the eclogite unit in the Besshi district show much higher Li/B ratio (ca. 0.36-1.99). Yoshida et al. (2011) pointed out that Li/B ratio of dehydrated fluids was controlled by the rock types of the host rocks, i.e., Li/B ratio of dehydrated fluids derived from tourmaline-free metasediments show much higher values than those expected from metabasites. Those obtained data suggest that the Li/B ratio of the deep fluid has a potential as a depth indicator but there remain many unknown factors for establishing it. The Li/B ratio of extracted fluid obtained by the crush-leached method integrates the whole fluid activities which the host rocks were taken place. To investigate the fluid activity history for the sample showing the highest Li/B ratio (1.99), detailed petrographical and microthemometric studies were performed. The studied sample IR04 is a foliation-parallel quartz vein intercalated with a Grt-Hbl-Ph schist probably derived from clay, whose peak P-T conditions are estimated as 600 °C and 1.3 GPa using pseudosection analysis. The quartz vein shows a foam microstructure, suggesting that low differential stress and high-T conditions were attained during its texture formation. Three types of fluid inclusions have been identified: the earliest one, FIA-I, is

  11. Fluid inclusion petrology and microthermometry of the Cocos Ridge hydrothermal system, IODP Expedition 344 (CRISP 2), Site U1414

    PubMed Central

    Brandstätter, Jennifer; Krenn, Kurt; Micheuz, Peter

    2016-01-01

    Abstract In this study, we present new data from microthermometry of fluid inclusions entrapped in hydrothermal veins along the Cocos Ridge from the IODP Expedition 344 Site U1414. The results of our study concern a primary task of IODP Expedition 344 to evaluate fluid/rock interaction linked with the tectonic evolution of the incoming Cocos Plate from the Early Miocene up to recent times. Aqueous, low saline fluids are concentrated within veins from both the Cocos Ridge basalt and the overlying lithified sediments of Unit III. Mineralization and crosscutting relationships give constraints for different vein generations. Isochores from primary, reequilibrated, and secondary fluid inclusions crossed with litho/hydrostatic pressures indicate an anticlockwise PT evolution during vein precipitation and modification by isobaric heating and subsequent cooling at pressures between ∼210 and 350 bar. Internal over and underpressures in the inclusions enabled decrepitation and reequilibration of early inclusions but also modification of vein generations in the Cocos Ridge basalt and in the lithified sediments. We propose that lithification of the sediments was accompanied with a first stage of vein development (VU1 and VC1) that resulted from Galapagos hotspot activity in the Middle Miocene. Heat advection, either related to the Cocos‐Nazca spreading center or to hotspot activity closer to the Middle America Trench, led to subsequent vein modification (VC2, VU2/3) related to isobaric heating. The latest mineralization (VC3, VU3) within aragonite and calcite veins and some vesicles of the Cocos Ridge basalt occurred during crustal cooling up to recent times. Fluid inclusion analyses and published isotope data show evidence for communication with deeper sourced, high‐temperature hydrothermal fluids within the Cocos Plate. The fluid source of the hydrothermal veins reflects aqueous low saline pore water mixed with invaded seawater. PMID:27570496

  12. Fluid inclusion petrology and microthermometry of the Cocos Ridge hydrothermal system, IODP Expedition 344 (CRISP 2), Site U1414

    NASA Astrophysics Data System (ADS)

    Brandstätter, Jennifer; Kurz, Walter; Krenn, Kurt; Micheuz, Peter

    2016-04-01

    In this study, we present new data from microthermometry of fluid inclusions entrapped in hydrothermal veins along the Cocos Ridge from the IODP Expedition 344 Site U1414. The results of our study concern a primary task of IODP Expedition 344 to evaluate fluid/rock interaction linked with the tectonic evolution of the incoming Cocos Plate from the Early Miocene up to recent times. Aqueous, low saline fluids are concentrated within veins from both the Cocos Ridge basalt and the overlying lithified sediments of Unit III. Mineralization and crosscutting relationships give constraints for different vein generations. Isochores from primary, reequilibrated, and secondary fluid inclusions crossed with litho/hydrostatic pressures indicate an anticlockwise PT evolution during vein precipitation and modification by isobaric heating and subsequent cooling at pressures between ˜210 and 350 bar. Internal over and underpressures in the inclusions enabled decrepitation and reequilibration of early inclusions but also modification of vein generations in the Cocos Ridge basalt and in the lithified sediments. We propose that lithification of the sediments was accompanied with a first stage of vein development (VU1 and VC1) that resulted from Galapagos hotspot activity in the Middle Miocene. Heat advection, either related to the Cocos-Nazca spreading center or to hotspot activity closer to the Middle America Trench, led to subsequent vein modification (VC2, VU2/3) related to isobaric heating. The latest mineralization (VC3, VU3) within aragonite and calcite veins and some vesicles of the Cocos Ridge basalt occurred during crustal cooling up to recent times. Fluid inclusion analyses and published isotope data show evidence for communication with deeper sourced, high-temperature hydrothermal fluids within the Cocos Plate. The fluid source of the hydrothermal veins reflects aqueous low saline pore water mixed with invaded seawater.

  13. Motions of deformable inclusions in a horizontally oscillating vessel with a compressible fluid

    NASA Astrophysics Data System (ADS)

    Demidov, I. V.; Sorokin, V. S.

    2016-11-01

    The paper is concerned with the analysis of rigid particle and compressible gas bubble motion in a horizontally oscillating vessel with a compressible fluid. A nonlinear differential equation describing motion of inclusions with respect to the vessel is derived and solved by the method of direct separation of motions. It is shown that rigid particles and gas bubbles can move both in nodes and antinodes of the pressure, depending on their size, density, and vibration parameters. The conditions under which different kinds of motion can incur have been determined. An expression for the critical radius of the bubbles which are affected by the negligible vibrational force is found. Also an approximate expression has been obtained for the average velocity of bubble's motion in the fluid; relationship between this velocity and bubble radius and vibration parameters has been revealed. A simple physical explanation of the noticed effects is proposed. Series of numerical experiments has been conducted, their results confirming those obtained theoretically. These results may be of interest for development of the flotation theory and other technological processes.

  14. Evidence from fluid inclusions for microbial methanogenesis in the early Archaean era.

    PubMed

    Ueno, Yuichiro; Yamada, Keita; Yoshida, Naohiro; Maruyama, Shigenori; Isozaki, Yukio

    2006-03-23

    Methanogenic microbes may be one of the most primitive organisms, although it is uncertain when methanogens first appeared on Earth. During the Archaean era (before 2.5 Gyr ago), methanogens may have been important in regulating climate, because they could have provided sufficient amounts of the greenhouse gas methane to mitigate a severely frozen condition that could have resulted from lower solar luminosity during these times. Nevertheless, no direct geological evidence has hitherto been available in support of the existence of methanogens in the Archaean period, although circumstantial evidence is available in the form of approximately 2.8-Gyr-old carbon-isotope-depleted kerogen. Here we report crushing extraction and carbon isotope analysis of methane-bearing fluid inclusions in approximately 3.5-Gyr-old hydrothermal precipitates from Pilbara craton, Australia. Our results indicate that the extracted fluids contain microbial methane with carbon isotopic compositions of less than -56 per thousand included within original precipitates. This provides the oldest evidence of methanogen (> 3.46 Gyr ago), pre-dating previous geochemical evidence by about 700 million years.

  15. In situ quantification of Br and Cl in minerals and fluid inclusions by LA-ICP-MS: a powerful tool to identify fluid sources

    USGS Publications Warehouse

    Hammerli, Johannes; Rusk, Brian; Spandler, Carl; Emsbo, Poul; Oliver, Nicholas H.S.

    2013-01-01

    Bromine and chlorine are important halogens for fluid source identification in the Earth's crust, but until recently we lacked routine analytical techniques to determine the concentration of these elements in situ on a micrometer scale in minerals and fluid inclusions. In this study, we evaluate the potential of in situ Cl and Br measurements by LA-ICP-MS through analysis of a range of scapolite grains with known Cl and Br concentrations. We assess the effects of varying spot sizes, variable plasma energy and resolve the contribution of polyatomic interferences on Br measurements. Using well-characterised natural scapolite standards, we show that LA-ICP-MS analysis allows measurement of Br and Cl concentrations in scapolite, and fluid inclusions as small as 16 μm in diameter and potentially in sodalite and a variety of other minerals, such as apatite, biotite, and amphibole. As a demonstration of the accuracy and potential of Cl and Br analyses by LA-ICP-MS, we analysed natural fluid inclusions hosted in sphalerite and compared them to crush and leach ion chromatography Cl/Br analyses. Limit of detection for Br is ~8 μg g−1, whereas relatively high Cl concentrations (> 500 μg g−1) are required for quantification by LA-ICP-MS. In general, our LA-ICP-MS fluid inclusion results agree well with ion chromatography (IC) data. Additionally, combined cathodoluminescence and LA-ICP-MS analyses on natural scapolites within a well-studied regional metamorphic suite in South Australia demonstrate that Cl and Br can be quantified with a ~25 μm resolution in natural minerals. This technique can be applied to resolve a range of hydrothermal geology problems, including determining the origins of ore forming brines and ore deposition processes, mapping metamorphic and hydrothermal fluid provinces and pathways, and constraining the effects of fluid–rock reactions and fluid mixing.

  16. Small scale metasomatism of mafic schist in the Norwegian Caledonides associated with brine infiltration - Fluid inclusions, SEM-CL and mineralogical record of the fluid infiltration

    NASA Astrophysics Data System (ADS)

    Drivenes, K.; Sorensen, B. E.; Larsen, R. B.

    2012-12-01

    The uppermost stratigraphic layer of a 250 meter thick sequence of metasediments in the Bjellaatinden area, Northern Norway, consists of a hornblende-biotite schist. The schist is cross cut by sub vertical, slightly arched, 2 - 10 cm thick quartz veins with an alteration halo up to 5 cm into the unaltered gneiss. The zoned alteration assemblage includes sericite, chlorite, calcite and muscovite. Hornblende is gradually altered to biotite, and plagioclase is increasingly sericitized towards the vein. Biotite is completely replaced by chlorite near the vein. Muscovite and calcite dominate closest to the quartz vein. The Fe/Fe+Mg ratio increases in biotite when partly altered to chlorite, and increases slightly in chlorite (0,55) compared to biotite (0,50) in the unaltered zones. Titanite is the main Ti-mineral in the unaltered gneiss, while ilmenite + rutile dominate in the alteration zone. An earlier hydrothermal mineral assembly consisting of scapolite (Me55-60) and biotite is also recognized Three types of fluid inclusions in quartz are described: Saline (ca. 40 wt% NaCl equiv.) water rich, gas rich, and low saline water rich. Multiple generations of fluids are indicated by several trails consisting of separate gas rich, saline water rich and low saline water rich inclusions. In some areas all three types occur together and are indicative of co-existence of different fluids in an immiscible fluid system. SEM-CL reveals three different types of quartz: Low lumicent, with a broad peak from 420 - 650 nm, hosting late, gas rich inclusions, higher lumicent, with a peak around 500 nm, hosting the saline fluid inclusions, and high lumicent with a peak around 500 nm scarce of fluid inclusions. Low saline, water rich fluids are mostly found in high lumicent quartz with a peak around 400 nm inside the alteration zone. Separate CO2 and H2O inclusions are found in scapolite and vein quartz related to scapolite. Microthermometry of the saline fluid inclusions revealed a

  17. Fluid inclusions and biomarkers in the Upper Mississippi Valley zinc-lead district; implications for the fluid-flow and thermal history of the Illinois Basin

    USGS Publications Warehouse

    Rowan, E. Lanier; Goldhaber, Martin B.

    1996-01-01

    The Upper Mississippi Valley zinc-lead district is hosted by Ordovician carbonate rocks at the northern margin of the Illinois Basin. Fluid inclusion temperature measurements on Early Permian sphalerite ore from the district are predominantly between 90?C and I50?C. These temperatures are greater than can be explained by their reconstructed burial depth, which was a maximum of approximately 1 km at the time of mineralization. In contrast to the temperatures of mineral formation derived from fluid inclusions, biomarker maturities in the Upper Mississippi Valley district give an estimate of total thermal exposure integrated over time. Temperatures from fluid inclusions trapped during ore genesis with biomarker maturities were combined to construct an estimate of the district's overall thermal history and, by inference, the late Paleozoic thermal and hydrologic history of the Illinois Basin. Circulation of groundwater through regional aquifers, given sufficient flow rates, can redistribute heat from deep in a sedimentary basin to its shallower margins. Evidence for regional-scale circulation of fluids is provided by paleomagnetic studies, regionally correlated zoned dolomite, fluid inclusions, and thermal maturity of organic matter. Evidence for igneous acti vity contemporaneous with mineralization in the vicinity of the Upper Mississippi Valley district is absent. Regional fluid and heat circulation is the most likely explanation for the elevated fluid inclusion temperatures (relative to maximum estimated burial depth) in the Upper Mississippi Valley district. One plausible driving mechanism and flow path for the ore-forming fluids is groundwater recharge in the late Paleozoic Appalachian-Ouachita mountain belt and northward flow through the Reelfoot rift and the proto- Illinois Basin to the Upper Mississippi Valley district. Warm fluid flowing laterally through Cambrian and Ordovician aquifers would then move vertically upward through the fractures that control

  18. The chemistry of brines from an Alpine thrust system in the central Pyrenees: An application of fluid inclusion analysis to the study of fluid behaviour in orogenesis

    SciTech Connect

    Banks, D.A.; Davies, G.R.; Yardley, B.W.D.; McCaig, A.M.; Grant, N.T. )

    1991-04-01

    Quartz filled veins and fractures which formed late in the Alpine thrusting of the Central Pyrenees contain inclusions of hypersaline Na-Ca-Cl brines with total dissolved salts of up to 25 wt{percent}. The total salinity is similar in all samples, irrespective of the vein or the wall rocks, but there are large variations in the chemistry of the fluids between samples. With one exception, each sample contains only a single dominant fluid population. Crush-leach extraction and chemical analysis of the inclusion electrolytes for Na, K, Ca, Mg, Ba, B, Li, Sr, Rb, Fe, Mn, Zn, Pb, F, Cl, Br, and Sr and Pb isotopes reveals that the fluid chemistry is strongly influenced by the local rocks. Of the four different lithologies in the thrust stack sampled, the Triassic mudstones and Cretaceous limestones or Silurian phyllites acted as sources for the vein fluids during the late thrusting. The composition of the fluid in the veins was dependent on the proximity to these lithologies. The similarity of the Br/Cl ratio (approximately twice seawater) and the consistent high salinity of all the inclusion fluids in the thrust stack indicate that they were all originally derived from a single source but progressively changed their cation and isotope chemistry through interaction with different host rocks. This ultimate source is likely to have been Triassic connate waters. The authors conclude that a local increase in permeability occurred when the veins formed and that fluid movement was over short distances. No evidence was found for a significant input of either surface or metamorphic fluids during thrusting.

  19. Regional fluid flow as a factor in the thermal history of the Illinois basin: Constraints from fluid inclusions and the maturity of Pennsylvanian coals

    USGS Publications Warehouse

    Rowan, E.L.; Goldhaber, M.B.; Hatch, J.R.

    2002-01-01

    Vitrinite reflectance measurements on Pennsylvanian coals in the Illinois basin indicate significantly higher thermal maturity than can be explained by present-day burial depths. An interval of additional sedimentary section, now removed by erosion, has been suggested to account for the discrepancy. Although burial could indeed account for the observed maturity levels of organic matter, fluid-inclusion temperatures provide a stringent additional constraint. In this article, we combine measurements of coal maturity with fluid-inclusion temperatures from three sites to constrain the basin's thermal and burial history: the Fluorspar district at the Illinois basin's southern margin, the Upper Mississippi Valley zinc district at the basin's northern margin, and a north-central location. Two-dimensional numerical modeling of a north-south cross section through the basin tests scenarios both with and without regional fluid flow. Vitrinite reflectance values can be matched assuming burial by 1.8-2.8 km of southward-thickening additional, post-Pennsylvanian sedimentary section. In the central and northern Illinois basin, however, these burial depths and temperatures are not sufficient to account for the fluid-inclusion data. To account for both parameters with burial alone does not appear feasible. In contrast, our best hypothesis assumes a wedge of post-Pennsylvanian sediment-thickening southward to about 1.2 km and a brief period of magmatism in the Fluorspar district. Significant advective heat redistribution by northward regional fluid flow accounts for fluid-inclusion temperatures and coal maturities throughout the basin. The modeling results demonstrate the potential contribution of advective heat transport to the thermal history of the Illinois basin.

  20. Microthermometry of enargite-hosted fluid inclusions from the Lepanto, Philippines, high-sulfidation Cu sbnd Au deposit

    NASA Astrophysics Data System (ADS)

    Mancano, D. P.; Campbell, A. R.

    1995-10-01

    The spatial relation between porphyry and high-sulfidation epithermal deposits is particularly well revealed in the Mankayan mineral district of northern Luzon, Philippines, where the Lepanto high-sulfidation Cu sbnd Au deposit lies over and adjacent to the Far Southeast (FSE) porphyry Cu sbnd Au deposit. Consequently, a study was undertaken to characterize the fluids responsible for epithermal mineralization in this environment. The ore stage at Lepanto consists of enargite-luzonite (Cu 3AsS 4), pyrite, tennantite-tetrahedrite, and chalcopyrite. Infrared petrography of the enargite reveals variable transparency, with growth banding and twinning visible in euhedral specimens. Two phase (liquid > vapor) fluid inclusions occur as primary and secondary types ranging from <1 to 80 micrometers in length, with tabular, cylindrical, or oval shapes. Homogenization temperatures ( Th) of fluid inclusions in enargite were measured from within the lateral (3.0 km) and vertical (0.5 km) extent of the enargite mineralization. These values show a cooling trend toward the northwest, away from the area over the porphyry deposit, with average Th ranging from 285°C (proximal) to 166°C (distal). Ice melting temperatures ( Tm) were measured using a cycling technique, as ice was usually not visible in frozen inclusions. Apparent salinities range from 4.5 to 0.2 eq. wt% NaCl, with samples from the margins of the deposit showing a general decrease in apparent salinity with lower Th. Secondary fluid inclusions in quartz phenocrysts tend to have a higher average Th and lower apparent salinities compared to enargite-hosted inclusion fluids from the same locations. Several samples of pyrite are also transparent to IR radiation, and show internal features such as growth banding, and in one instance a two phase (liquid > vapor) fluid inclusion. This inclusion yielded a salinity of 1.2 eq. wt% NaCl. There is a large discrepancy in Th and apparent salinities between the enargite mineralization

  1. Different carbon reservoirs of auriferous fluids in African Archean and Proterozoic gold deposits? Constraints from stable carbon isotopic compositions of quartz-hosted CO2-rich fluid inclusions

    NASA Astrophysics Data System (ADS)

    Lüders, Volker; Klemd, Reiner; Oberthür, Thomas; Plessen, Birgit

    2015-04-01

    Stable carbon (and when present, nitrogen) isotope ratios of fluid inclusions in quartz from selected gold deposits in Ghana and Zimbabwe have been analyzed using a crushing device interfaced to an isotopic ratio mass spectrometer (IRMS) in order to constrain possible sources of the auriferous fluids. The study revealed a striking difference in stable carbon isotopic compositions of CO2 in quartz-hosted fluid inclusions from Archean and Paleoproterozoic orogenic gold deposits and points to diverse sources of CO2 in the studied deposits. Whether this finding can be generalized for other Archean and Proterozoic orogenic gold deposits worldwide remains open. However, a significant CO2 contribution by mantle degassing can be ruled out for every deposit studied. Devolatilization of greenstone belt rocks is the most likely source for CO2 in some Archean Au deposits in Zimbabwe, whereas CO2 in Proterozoic vein-type Au deposits in the West African Craton is most likely derived from Corg-bearing metasedimentary rocks. The δ13CCO2 values of high-density CO2-rich, water-poor inclusions hosted in quartz pebbles from the world-class Au-bearing conglomerate deposits at Tarkwa (Ghana) differ considerably from the δ13CCO2 values of similar high-density CO2-rich inclusions in vein quartz from the giant Ashanti deposit (Ghana) and disprove the idea of derivation of the Tarkwaian quartz (and gold?) from an older equivalent to the Ashanti vein-type gold deposit.

  2. A possible genetic model of the Shuangwang hydrothermal breccia gold deposit, Shaanxi Province, central China: Evidence from fluid inclusion and stable isotope

    NASA Astrophysics Data System (ADS)

    Wang, Jianping; Liu, Jiajun; Carranza, Emmanuel John M.; Liu, Zhenjiang; Liu, Chonghao; Liu, Bizheng; Wang, Kexin; Zeng, Xiangtao; Wang, Huan

    2015-11-01

    The Shuangwang gold deposit (with a gold resource of approximately 70 t Au), hosted in a NW-trending breccia belt, is located in the Fenxian-Taibai fore-arc basin in the West Qinling Orogen of central China. Four stages of ore paragenesis are identified, demonstrating mineral assemblages of ankerite-quartz-albite, quartz-albite-pyrite-ankerite, pyrite-calcite-quartz, and fluorite-dickite-gypsum, respectively. Fluid inclusions hosted in stages I, II, and III hydrothermal minerals yield homogeneous temperatures of 300-463 °C, 220-340 °C and 100-279 °C, with salinities lower than 22.7 wt% NaCl equiv. Trapping pressures estimated from CO2-H2O fluid inclusions show a gradual decrease from 100-170 MPa (KT8 ore body) to 17-55 MPa (KT2 ore body), corresponding to mineralization depths from 3.8-6.4 km (KT8) to 0.6-2.1 km (KT2). Hydrogen and oxygen isotopic data suggest that the ore-forming fluids evolved from metamorphic water to magmatic water, and lately meteoric water. Sulfur and carbon isotope compositions show that these fluids might have originated from interaction with the host rocks with minor additional magmatic source. Based on geochemical investigations, with combination of regional and ore deposit geology, a possible genetic model with a three-step ore-forming process is proposed. The Devonian Xinghongpu sedimentary rocks are characterized by a relatively high gold content, which might provide the initial gold source. Linear folds and faults formed during Triassic orogenic processes provided the subsequent pathways for ore-forming fluids and suitable space for gold mineralization. Postorogenic magmatic activity induced voluminous hydrothermal fluids that mixed with the basinal fluids and may have started the ore formation process. Over pressure led to hydrofracturing and the subsequent pressure drop promoted fluid boiling, which in turn resulted in abundant gold deposition. Induced by postorogenic magmatic hydrothermal activity, the Shuangwang gold deposit is

  3. Re-Os sulfide (chalcopyrite, pyrite and molybdenite) systematics and fluid inclusion study of the Duobaoshan porphyry Cu (Mo) deposit, Heilongjiang Province, China

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Wu, Guang; Li, Yuan; Zhu, Mingtian; Zhong, Wei

    2012-04-01

    The Duobaoshan porphyry deposit, located in the northwestern part of the Lesser Hinggan Range, is one of the biggest porphyry Cu (Mo) deposits in the Central Asian orogenic belt in China. The Duobaoshan porphyry deposit occurs in granodiorite and volcanic rocks of the Middle Ordovician Duobaoshan Formation. Six types of veins have been identified in three ore-forming stages as follows: a quartz-potassic feldspar vein in the early ore-forming stage, an early stage quartz-molybdenite vein, late stage quartz-molybdenite and quartz-chalcopyrite-pyrite veins in the middle ore-forming stage, and quartz-pyrite and calcite-quartz veins in the late ore-forming stage. The following four types of fluid inclusions are distinguished from various quartz veins: two-phase aqueous, pure gas phase, CO2-bearing and daughter mineral-bearing inclusions. The ore-forming fluid for the early ore-forming stage belongs to the H2O-CO2-NaCl system, which is characterized by high temperatures (>550 °C), intermediate salinities (16.2-18.1 wt% NaCl eqv.) and high CO2 content. The ore-forming fluid from the middle ore-forming stage evolved to the H2O-CO2-NaCl system, which is characterized by intermediate to high temperatures (230-450 °C) and high/low salinities (0.8 to >65.3 wt% NaCl eqv.) and is also rich in CO2 and metals. The ore-forming fluid finally reached cool temperatures (110-200 °C), low salinities (3.9-8.4 wt% NaCl eqv.) and was CO2-poor. Intensive fluid immiscibility or boiling occurred when the ore-forming fluid with temperatures of 230-450 °C and pressures of 10-41 MPa ascended to 4.1 km, inducing the escape of CO2, depressing the solubility of fluid, and depositing abundant metal sulfides. The total Re and Os concentrations of chalcopyrite and pyrite range from 0.15 to 2.95 μg/g and 0.74 to 15.01 ng/g, respectively. Analyses of seven chalcopyrite and pyrite samples yielded isochron ages of 482-486 Ma, and the model age of one molybdenite sample is 485.6 ± 3.7 Ma. The

  4. Mineralogy and fluid inclusions study of carbonate-hosted Mississippi valley-type Ain Allega Pb-Zn-Sr-Ba ore deposit, Northern Tunisia

    NASA Astrophysics Data System (ADS)

    Abidi, R.; Slim-Shimi, N.; Somarin, A.; Henchiri, M.

    2010-05-01

    The Ain Allega Pb-Zn-Sr-Ba ore deposit is located in the flysch zone on the Eastern edge of the Triassic diapir of Jebel Hamra. It is part of the extrusive Triassic evaporate formation along the Ghardimaou-Cape Serrat faults. The ore body consists of argilic-dolomite breccias surrounded by argilo-gypsum Triassic formation, which forms the hanging wall of the deposit, and rimmed by the Paleocene marls. The ore minerals show a cap-rock type mineralization with different styles particularly impregnation in dolomite, cement of breccias, replacement ore and open space filling in the dissolution cavities and fractures. Ore minerals include sphalerite, galena, marcasite and pyrite. Principal gangue minerals are composed of barite, celestite, calcite, dolomite and quartz. The ore minerals are hosted by the Triassic carbonate rocks which show hydrothermal alteration, dissolution and brecciation. X-ray - crystallographic study of barite-celestite mineral series shows that pure barite and celestite are the abundant species, whereas strontianiferous barite (85-96.5% BaSO 4) and barian-celestite (95% SrSO 4) are minor. Primary and secondary mono-phase (liquid only) fluid inclusions are common in celestite. Microthermometric analyses in two-phases (liquid and vapour) fluid inclusions suggest that gangue and ore minerals were precipitated by a low-temperature (180 °C) saline (16.37 wt.% NaCl equivalent) solution originated possibly from a basinal brine with some input from magmatic or metamorphic fluid. Based on geology, mineralogy, texture and fluid characteristics, the Ain Allega deposit is classified as a carbonate-hosted Mississippi valley-type deposit.

  5. Determination of the internal pressure of fluid inclusions by using Raman spectroscopy.

    PubMed

    Yang, Yuping; Zheng, Haifei; Sun, Qiang; Li, Jiankang; Chen, Zhenghui

    2013-07-01

    In situ Raman spectroscopic measurements of H2O-NaCl systems with three different salinities (0, 5.0, and 10.0 wt% NaCl) in the region of O-H stretching vibration were obtained at pressures up to 1800 MPa and temperatures from 298 to 453 K, with a hydrothermal diamond-anvil cell. The peak position was determined by fitting the obtained O-H stretching band with one Gaussian component. At a given temperature, the shift of the band decreased systematically with increasing pressure, and the data show a good linear relationship. For systems of different salinity, the slopes of the isotherms seem to be independent of temperature under the conditions investigated. With increasing salinity, the slope of the isotherm gradually increases. The relationships measured for the shift of the O-H stretching band with temperature, salinity, and pressure can be used to determine the internal pressure and isochore of fluid inclusions as well as the formation temperature and pressure of host minerals. PMID:23816134

  6. Determination of the internal pressure of fluid inclusions by using Raman spectroscopy.

    PubMed

    Yang, Yuping; Zheng, Haifei; Sun, Qiang; Li, Jiankang; Chen, Zhenghui

    2013-07-01

    In situ Raman spectroscopic measurements of H2O-NaCl systems with three different salinities (0, 5.0, and 10.0 wt% NaCl) in the region of O-H stretching vibration were obtained at pressures up to 1800 MPa and temperatures from 298 to 453 K, with a hydrothermal diamond-anvil cell. The peak position was determined by fitting the obtained O-H stretching band with one Gaussian component. At a given temperature, the shift of the band decreased systematically with increasing pressure, and the data show a good linear relationship. For systems of different salinity, the slopes of the isotherms seem to be independent of temperature under the conditions investigated. With increasing salinity, the slope of the isotherm gradually increases. The relationships measured for the shift of the O-H stretching band with temperature, salinity, and pressure can be used to determine the internal pressure and isochore of fluid inclusions as well as the formation temperature and pressure of host minerals.

  7. A salt diapir-related Mississippi Valley-type deposit: the Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: fluid inclusion and isotope study

    NASA Astrophysics Data System (ADS)

    Bouhlel, Salah; Leach, David L.; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-08-01

    The Bou Jaber Ba-F-Pb-Zn deposit is located at the edge of the Bou Jaber Triassic salt diapir in the Tunisia Salt Diapir Province. The ores are unconformity and fault-controlled and occur as subvertical column-shaped bodies developed in dissolution-collapse breccias and in cavities within the Late Aptian platform carbonate rocks, which are covered unconformably by impermeable shales and marls of the Fahdene Formation (Late Albian-Cenomanian age). The host rock is hydrothermally altered to ankerite proximal to and within the ore bodies. Quartz, as fine-grained bipyramidal crystals, formed during hydrothermal alteration of the host rocks. The ore mineral assemblage is composed of barite, fluorite, sphalerite, and galena in decreasing abundance. The ore zones outline distinct depositional events: sphalerite-galena, barite-ankerite, and fluorite. Fluid inclusions, commonly oil-rich, have distinct fluid salinities and homogenization temperatures for each of these events: sphalerite-galena (17 to 24 wt% NaCl eq., and Th from 112 to 136 °C); ankerite-barite (11 to 17 wt% NaCl eq., and Th from 100 to 130 °C); fluorite (19 to 21 wt% NaCl eq., Th from 140 to 165 °C). The mean temperature of the ore fluids decreased from sphalerite (125 °C) to barite (115 °C) and increased during fluorite deposition (152 °C); then decreased to ˜110 °C during late calcite precipitation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of fluid inclusions in fluorite are metal rich (hundreds to thousands ppm Pb, Zn, Cu, Fe) but the inclusions in barite are deficient in Pb, Zn, Cu, Fe. Inclusions in fluorite have Cl/Br and Na/Br ratios of several thousand, consistent with dissolution of halite while the inclusions analysed in barite have values lower than seawater which are indicative of a Br-enriched brine derived from evaporation plus a component of halite dissolution. The salinity of the barite-hosted fluid inclusions is less than obtained simply by the

  8. Magmatogene fluids of metal-bearing reefs in the Bushveld Complex, South Africa: Based on research data on fluid inclusions in quartz

    NASA Astrophysics Data System (ADS)

    Zhitova, L. M.; Kinnaird, J. A.; Gora, M. P.; Shevko, E. P.

    2016-01-01

    Fluid inclusions in the Merensky Reef quartz and later pegmatite veins crosscutting the Platreef rocks of the Bushveld Complex are studied by a suite of advanced high-precision methods. Based on the conducted studies, we identify a few types of fluids, some having been separated during the crystallization of volatile matter-rich residual melt of original basic magma, while others are derivatives of later felsic (granite) melts that formed crosscutting veins in fully devitrified ultrabasic and basic rocks. The earliest fluid is captured by quartz in symplectitic intergrowths with intercumulus plagioclase from the Merensky Reef pyroxenite occurs as a homogenous dense dry reduced gas (CH4-N2 ± CO2) mixture separated from the aluminosilicate melt at 800-900°C and 3050 bar. The following heterophase highly concentrated fluids (60-80 wt % NaCl eq.) separated at over 550°C and below 3050 bar transport a large number of metals. Major saline components of such fluids included Na, K, Fe, Ca, and Mn chlorides, Ca and Na sulphates and carbonates. According to LA ICP-MS analysis data, inclusions of these fluids contain high concentrations of Fe, Cr, K, and Na at the level of a few wt % and also significant contents of Cu, Sn, Sb, Mo, Au, Ag, Bi, and Ni in a concentration range from a few to thousands of ppm. Relatively lower-temperature (much higher than 450°C) fluids accompanying the crystallization of crosscutting quartz-feldspar pegmatite veins at the Platreef are also highly concentrated (from 70-80% to 40-14 wt % NaCl eq.), oxidized and metal-bearing. High concentrations of metals such as Na, K, Ca, Mn, Fe, and Pb at the level of wt % and also Ni, Co, Cu, As, Mo, Sn, Sb, and Bi (1-500 ppm) in inclusions in quartz of later pegmatite veins suggest the possible participation of magmatogene fluids related to later felsic intrusions in the redistribution of primary magmatic concentrations of metals. The oxidation of reduced heterophase fluids may be the most important

  9. Simulation of Fluid and Inclusions Dynamics during Filtration Operations of Ductile Iron Melts Using Foam Filters

    NASA Astrophysics Data System (ADS)

    Dávila-Maldonado, O.; Adams, A.; Oliveira, L.; Alquist, B.; Morales, R. D.

    2008-12-01

    The use of ceramic foam filters in ductile iron foundries to reduce the number of inclusions that reach the casting has been widely accepted. However, the exact mechanisms contributing to foam filter effectiveness are not yet known; this limits the ability to maximize filter performance and inclusion reduction. The objective of this work is to qualify and quantify the effects of the foam filter structure on inclusion retention. This has been accomplished through the development of a three-dimensional (3-D) mathematical model, based on physical water modeling and mathematical simulations. It was found that the casting rate and inclusion density play minor roles in the capture ratio, while inclusion size is the most influent variable. One mechanism for capturing inclusions involves the direct impact of an inclusion on the web wall and its adhesion after crossing over the liquid film. Two additional mechanisms involve the entrainment of inclusions by buoyancy-lift forces into low-velocity fields and the ulterior adhesion through buoyancy effects. The second mechanism is the entrainment of inclusions into microrecirculating flows; the inclusions remain in these flows for times that exceed the mold filling time. The latter mechanism has limited intensity for inclusions approximately 30 to 100 μm in size. In order to enhance the effects of this mechanism in this range of sizes, the vorticity magnitude in the microfree shear flows in the filter’s pores must be increased, through changes in the structure geometry of this device.

  10. Base and precious metal-bearing fluid inclusions of magmatic origin in the Ultramafic Series of the Stillwater Complex, Montana

    NASA Astrophysics Data System (ADS)

    Hanley, J.; Pettke, T.; Mungall, J.; Spooner, E.

    2004-05-01

    Fluid inclusions in the Ultramafic Series below the PGE (platinum-group element)-bearing JM reef of the Stillwater Complex are being characterized to evaluate whether these rocks were the source of platiniferous fluids, which redistributed and possibly enriched base- and precious metals in the deposit. Fluid inclusions of primary origin are hosted in quartz in graphic-textured (eutectic) albite-quartz intergrowths and in massive quartz in the core of a plagioclase-pyroxene-quartz pegmatoid. Secondary inclusions containing similar fluid compositions also occur along healed fracture planes in unaltered Mg-rich olivine (~Fo84) in phlogopite-rich pyroxenite that hosts the pegmatoid. Within quartz in the albite-quartz intergrowth, the earliest forming inclusions are primary inclusions containing high density (0.87-0.97; n=10) CO2 liquid (one phase at room T) containing trace (not visible) amounts of NaCl-bearing aqueous fluid. In pegmatoid core (in massive quartz; no albite), coexisting primary inclusions containing either CO2 liquid (with traces of NaCl-bearing aqueous fluid) or hypersaline aqueous fluid are observed. CO2 liquid inclusions in the massive quartz core are of lower density (0.78-0.83; n=11) and have melting Ts slightly below that of pure CO2 (-57.1 to -57.9° C; n=11) suggesting additional volatiles components (e.g. CO, N2, CH4). Inclusions containing the hypersaline brine (52±6 wt% NaCl eq; 1σ , n=31) homogenize by halite dissolution at T > 450° C. Solid phases identified in the brine inclusions are: halite, sylvite, enargite (Cu3AsS4), Ca-(Fe-Mn) carbonates, hematite, and K-feldspar. Olivine-hosted brine inclusions homogenize also by halite dissolution (430-470° C; n=16). A preliminary trapping temperature estimate for the brine inclusions at P=3-4 kbar (peak contact metamorphic conditions) is 570-590° C. The coeval fluid types may be the result of unmixing of a single NaCl-H2O-CO2 fluid phase which exsolved from crystallizing interstitial

  11. Fluid inclusions and preliminary studies of hydrothermal alteration in core hole PLTG-1, Platanares geothermal area, Honduras

    USGS Publications Warehouse

    Bargar, K.E.

    1991-01-01

    The Platanares geothermal area in western Honduras consists of more than 100 hot springs that issue from numerous hot-spring groups along the banks or within the streambed of the Quebrada de Agua Caliente (brook of hot water). Evaluation of this geothermal area included drilling a 650-m deep PLTG-1 drill hole which penetrated a surface mantling of stream terrace deposits, about 550 m of Tertiary andesitic lava flows, and Cretaceous to lower Tertiary sedimentary rocks in the lower 90 m of the drill core. Fractures and cavities in the drill core are partly to completely filled by hydrothermal minerals that include quartz, kaolinite, mixed-layer illite-smectite, barite, fluorite, chlorite, calcite, laumontite, biotite, hematite, marcasite, pyrite, arsenopyrite, stibnite, and sphalerite; the most common open-space fillings are calcite and quartz. Biotite from 138.9-m depth, dated at 37.41 Ma by replicate 40Ar/39 Ar analyses using a continuous laser system, is the earliest hydrothermal mineral deposited in the PLTG-1 drill core. This mid-Tertiary age indicates that at least some of the hydrothermal alteration encountered in the PLTG-1 drill core occured in the distant past and is unrelated to the present geothermal system. Furthermore, homogenization temperatures (Th) and melting-point temperatures (Tm) for fluid inclusions in two of the later-formed hydrothermal minerals, calcite and barite, suggest that the temperatures and concentration of dissolved solids of the fluids present at the time these fluid inclusions formed were very different from the present temperatures and fluid chemistry measured in the drill hole. Liquid-rich secondary fluid inclusions in barite and caicite from drill hole PLTG-1 have Th values that range from about 20??C less than the present measured temperature curve at 590.1-m depth to as much as 90??C higher than the temperature curve at 46.75-m depth. Many of the barite Th measurements (ranging between 114?? and 265??C) plot above the

  12. Geology, mineralization, stable isotope geochemistry, and fluid inclusion characteristics of the Novogodnee-Monto oxidized Au-(Cu) skarn and porphyry deposit, Polar Ural, Russia

    NASA Astrophysics Data System (ADS)

    Soloviev, Serguei G.; Kryazhev, Sergey G.; Dvurechenskaya, Svetlana S.

    2013-06-01

    The Novogodnee-Monto oxidized Au-(Cu) skarn and porphyry deposit is situated in the large metallogenic belt of magnetite skarn and Cu-Au porphyry deposits formed along the Devonian-Carboniferous Urals orogen. The deposit area incorporates nearly contemporaneous Middle-Late Devonian to Late Devonian-Early Carboniferous calc-alkaline (gabbro to diorite) and potassic (monzogabbro, monzodiorite- to monzonite-porphyry, also lamprophyres) intrusive suites. The deposit is represented by magnetite skarn overprinted by amphibole-chlorite-epidote-quartz-albite and then sericite-quartz-carbonate assemblages bearing Au-sulfide mineralization. This mineralization includes early high-fineness (900-990 ‰) native Au associated mostly with cobaltite as well as with chalcopyrite and Co-pyrite, intermediate-stage native Au (fineness 830-860 ‰) associated mostly with galena, and late native Au (760-830 ‰) associated with Te minerals. Fluid inclusion and stable isotope data indicate an involvement of magmatic-hydrothermal high-salinity (>20 wt.% NaCl-equiv.) chloride fluids. The potassic igneous suite may have directly sourced fluids, metals, and/or sulfur. The abundance of Au mineralization is consistent with the oxidized character of the system, and its association with Co-sulfides suggests elevated sulfur fugacity.

  13. Mineral thermobarometry and fluid inclusion studies on the Closepet granite, Eastern Dharwar Craton, south India: Implications to emplacement and evolution of late-stage fluid

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sourabh; Panigrahi, Mruganka K.; Jayananda, M.

    2014-09-01

    The Closepet granite (CPG), a spectacularly exposed magmatic body along with other intrusive bodies (to the east of it) typifies the late Archean granitic activity in the Eastern Dharwar Craton (EDC), south India. In the present study, the P-T-fO2 conditions of emplacement and physico-chemical environment of the associated magmatic-hydrothermal regime of CPG have been retrieved on the basis of mineral chemical and fluid inclusion studies. Amphibole-plagioclase Ti-in-amphibole and Ti-in-biotite geothermometers along with Al-in-amphibole geobarometer have been used to reconstruct the emplacement temperature and pressure conditions in the majority of the pluton. Estimated temperatures of emplacement of CPG vary from to 740 to 540 °C. A variation of pressure from 4.8 to 4.1 kilo bars corresponding to this temperature range was obtained. While there is a faint south to north negative gradient in temperature, the variation of pressure does not seem to follow this trend and indicates more or less same crustal level of emplacement for the body between Ramanagaram-Kalyandurga segment extending for about 230 km. Mineral chemistry of biotite indicates crystallization of CPG under high oxygen fugacity conditions (mostly above QFM buffer) with no clear spatial variation in the fugacity of halogen species in the late-stage magmatic fluid. It may be surmised that barring the southernmost part of CPG, there is no perceptible variation in the physicochemical environment of emplacement. Fluid Inclusion studies in the granitic matrix quartz and pegmatite/vein quartz show dominance of H2O and H2O-CO2 fluids respectively in them. The difference in the fluid characteristics is interpreted in terms of the initial loss of CO2 rich fluid from granitic magma and aqueous-rich nature during the later stages of crystallization of quartz. The exsolved CO2-rich fluid was responsible in formation of the later quartz and pegmatitic veins at different crustal levels and also possibly was

  14. External micro-PIXE analysis of fluid inclusions: Test of the LABEC facility on samples of quartz veins from Apuan Alps (Italy)

    NASA Astrophysics Data System (ADS)

    Massi, M.; Calusi, S.; Giuntini, L.; Ruggieri, G.; Dini, A.

    2008-05-01

    Fluid inclusions are small portions, usually smaller than 100 μm, of fluid trapped within minerals during or after growth. Their characteristics provide therefore fundamental information on nature and evolution of fluids present in the past in different geological environments. At the LABEC laboratory in Firenze, high-salinity fluid inclusions in quartz crystals, coming from the Apuan Alps metamorphic complex, were analysed at the external scanning microbeam. Results, although still preliminary, have already provided us with hints on fluid-rock interaction processes during the metamorphism of the Apuan Alps.

  15. Fluid inclusion petrography and microthermometry of the Cocos Ridge hydrothermal system, IODP Expedition 344 (CRISP 2), Site U1414

    NASA Astrophysics Data System (ADS)

    Brandstätter, J.; Kurz, W.; Krenn, K.; Micheuz, P.

    2015-12-01

    We present new data from microthermometric analyses of fluid inclusions entrapped in hydrothermal veins within lithified sediments and Cocos Ridge (CCR) basalt from IODP Expedition 344 site U1414 (Costa Rica) and concern on a primary task of Expedition 344, i.e. to evaluate fluid/rock interaction, the hydrologic system, and the geochemical processes (indicated by composition and volume of fluids) active within the incoming Cocos Plate. Mineralization of the veins and crosscutting relationships gives constraints for the different generation of veins. Calcium carbonate, commonly aragonite in the upper part and calcite in the lower part of the igneous basement, is usually present in veins as a late phase following the quartz precipitation and the clay minerals formation. The sequence of vein generations in the lithified sediments close to the contact within the CCR basalt is characterized by smaller veins filled by quartz, followed by massive intersecting calcite veins. A high fluid pressure can be concluded, due to wall rock fragments embedded within the filling and fractured mineral grains in the ground mass, which are close to the veins. This requires that the magmatic basement and the lithified sediments were covered by sequences of low permeability sediments forming a barrier that enabled build up elevated fluid pressure. The investigation of fluid inclusions in the lowest units of borehole 344-U1414, give clues about the source of the fluids and about the vein evolution within the incoming Cocos Plate close to Middle American Trench. The microthermometric analyses of the primary, almost aqueous, inclusions indicate a temperature range during entrapment between 200 and 420°C. The data indicate that seawater within the Cocos Ridge aquifer communicated with high-temperature fluids and/or were modified by heat advection. We consider the Galapagos hotspot and/ or the Cocos-Nazca spreading center as heat source. Fluids originated from mobilized sediment pore water

  16. Diagenesis associated with subaerial exposure of Miocene strata, southeastern Spain: Implications for sea-level change and preservation of low-temperature fluid inclusions in calcite cement

    USGS Publications Warehouse

    Goldstein, R.H.; Franseen, E.K.; Mills, M.S.

    1990-01-01

    Many ancient carbonate rocks contain calcite cements that precipitated from shallow, fresh groundwater that entered strata during events of subaerial exposure. Such low-temperature cementation may be difficult to interpret from fluid inclusion studies because some of the inclusions may reequilibrate during later thermal events. Miocene rocks of southeast Spain provide an example of the utility of fluid inclusion studies in rocks that have not been subjected to significant heating. In the Mesa Roldan area, one type of calcite cement occurs exclusively below a regional stratigraphic surface of enigmatic origin. The cement has petrographic characteristics indicative of cementation in the vadose zone (generally thought to be a zone of oxidation) but has cathodoluminescent bands containing reduced manganese and iron. Primary fluid inclusions contain mostly fresh water, have variable ratios of vapor to liquid, and are at one atmosphere of pressure. Our observations indicate that calcite precipitated from a freshwater vadose zone, which was subjected to local or repetitive saturation, and minor brackish water. The fluid inclusion data indicate that low-temperature fluid inclusions can be preserved in ancient sequences despite a later history of different pore fluids. This indication of subaerial diagenesis of distal slope deposits suggests a relative sea-level drop of at least 50-55 m during the Late Miocene. Similar petrographic and fluid inclusion observations can be used to interpret sea-level changes in other areas. ?? 1990.

  17. Fracture-controlled fluid flow in the Farnham Dome anticline: Insights from combined fluid-inclusion analysis and clumped-isotope thermometry of carbonate veins

    NASA Astrophysics Data System (ADS)

    Luetkemeyer, P. Benjamin; Kirschner, David L.; Huntington, Katharine W.

    2015-04-01

    This study presents clumped-isotope, stable-isotope, and fluid-inclusion analyses of carbonate veins in the context of their structural and stratigraphic positions in order to characterize the fracture-controlled fluid flow system in the Farnham Dome anticline, east-central, Utah. Four sets of open- and shear-mode fractures and veins are recognized throughout the fold and are represented in the shale-sandstone-shale sequence at outcrop scale. Samples were selected from each vein set in different structural and stratigraphic positions. There is no correlation between the isotopic values of the veins and inclusion fluids with vein type, but there is a correlation with structural stratigraphic position. δ13C values of calcite veins within the footwall and fold hinge units (Cedar Mountain Shale and Dakota Sandstone) fall within the range of about -3 to -8 ‰ (VPDB), while calcite veins located within the hangingwall (Tununk Member of the Mancos Shale) have δ13C values that fall within a narrow range of -0.3 to -0.8 ‰ (VPDB). δ18O values of calcite veins from the Cedar Mountain and Tununk shales cluster between +17 to +20 ‰ (VSMOW), consistent with syn-fold faulting that creates structural fluid pathways and separates portions of the fold into fluid compartments. δ13C and δ18O values of veins tend to be lower than those of their host rocks consistent with fluid-dominated or fluid-buffered system, likely related to significant fluid flow through discrete planes of fractures. Homogenization temperatures (Th) and salinities of sparse two-phase inclusions were measured on selected samples. Salinities for all units are between 0 to 3.5 wt% NaCl equivalent and Th values between 80 to 130 °C. The Th and salinities differ slightly among host rocks. Salinities are systematically higher with lower Th values in both shale units. Th and salinity do not vary systematically in the Dakota sandstone. These results are consistent with higher hydraulic connectivity in

  18. Radiation-Dependent Limit for the Viability of Bacterial Spores in Halite Fluid Inclusions and on Mars

    PubMed Central

    Kminek, Gerhard; Bada, Jeffrey L.; Pogliano, Kit; Ward, John F.

    2014-01-01

    Kminek, G., Bada, J. L., Pogliano, K. and Ward, J. F. Radiation-Dependent Limit for the Viability of Bacterial Spores in Halite Fluid Inclusions and on Mars. Radiat. Res. 159, 722–729 (2003). When claims for the long-term survival of viable organisms are made, either within terrestrial minerals or on Mars, considerations should be made of the limitations imposed by the naturally occurring radiation dose to which they have been exposed. We investigated the effect of ionizing radiation on different bacterial spores by measuring the inactivation constants for B. subtilis and S. marismortui spores in solution as well as for dry spores of B. subtilis and B. thuringiensis. S. marismortui is a halophilic spore that is genetically similar to the recently discovered 2-9-3 bacterium from a halite fluid inclusion, claimed to be 250 million years old (Vreeland et al., Nature 407, 897–900, 2000). B. thuringiensis is a soil bacterium that is genetically similar to the human pathogens B. anthracis and B. cereus (Helgason et al., Appl. Environ. Microbiol. 66, 2627–2630, 2000). To relate the inactivation constant to some realistic environments, we calculated the radiation regimen in a halite fluid inclusion and in the Martian subsurface over time. Our conclusion is that the ionizing dose of radiation in those environments limits the survival of viable bacterial spores over long periods. In the absence of an active repair mechanism in the dormant state, the long-term survival of spores is limited to less than 109 million years in halite fluid inclusions, to 100 to 160 million years in the Martian subsurface below 3 m, and to less than 600,000 years in the uppermost meter of Mars. PMID:12751954

  19. A salt diapir-related Mississippi Valley-type deposit: the Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: fluid inclusion and isotope study

    NASA Astrophysics Data System (ADS)

    Bouhlel, Salah; Leach, David L.; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-08-01

    The Bou Jaber Ba-F-Pb-Zn deposit is located at the edge of the Bou Jaber Triassic salt diapir in the Tunisia Salt Diapir Province. The ores are unconformity and fault-controlled and occur as subvertical column-shaped bodies developed in dissolution-collapse breccias and in cavities within the Late Aptian platform carbonate rocks, which are covered unconformably by impermeable shales and marls of the Fahdene Formation (Late Albian-Cenomanian age). The host rock is hydrothermally altered to ankerite proximal to and within the ore bodies. Quartz, as fine-grained bipyramidal crystals, formed during hydrothermal alteration of the host rocks. The ore mineral assemblage is composed of barite, fluorite, sphalerite, and galena in decreasing abundance. The ore zones outline distinct depositional events: sphalerite-galena, barite-ankerite, and fluorite. Fluid inclusions, commonly oil-rich, have distinct fluid salinities and homogenization temperatures for each of these events: sphalerite-galena (17 to 24 wt% NaCl eq., and Th from 112 to 136 °C); ankerite-barite (11 to 17 wt% NaCl eq., and Th from 100 to 130 °C); fluorite (19 to 21 wt% NaCl eq., Th from 140 to 165 °C). The mean temperature of the ore fluids decreased from sphalerite (125 °C) to barite (115 °C) and increased during fluorite deposition (152 °C); then decreased to ˜110 °C during late calcite precipitation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of fluid inclusions in fluorite are metal rich (hundreds to thousands ppm Pb, Zn, Cu, Fe) but the inclusions in barite are deficient in Pb, Zn, Cu, Fe. Inclusions in fluorite have Cl/Br and Na/Br ratios of several thousand, consistent with dissolution of halite while the inclusions analysed in barite have values lower than seawater which are indicative of a Br-enriched brine derived from evaporation plus a component of halite dissolution. The salinity of the barite-hosted fluid inclusions is less than obtained simply by the

  20. Radiation-Dependent Limit for the Viability of Bacterial Spores in Halite Fluid Inclusions and on Mars

    NASA Technical Reports Server (NTRS)

    Kminek, Gerhard; Bada, Jeffrey L.; Pogliano, Kit; Ward, John F.

    2003-01-01

    When claims for the long-term survival of viable organisms are made, either within terrestrial minerals or on Mars, considerations should be made of the limitations imposed by the naturally occurring radiation dose to which they have been exposed. We investigated the effect of ionizing radiation on different bacterial spores by measuring the inactivation constants for B. subtilis and s. marismortui spores in solution as well as for dry spores of B. subtilis and B. thuringiensis. S. marismortui is a halophilic spore that is genetically similar to the recently discovered 2-9-3 bacterium from a halite fluid inclusion, claimed to be 250 million years old, B. thuringiensis is a soil bacterium that is genetically similar to the human pathogens B. anthracis and B. cereus. To relate the inactivation constant to some realistic environments, we calculated the radiation regimen in a halite fluid inclusion and in the Martian subsurface over time. Our conclusion is that the ionizing dose of radiation in those environments limits the survival of viable bacterial spores over long periods. In the absence of an active repair mechanism in the dormant state, the long-term survival of spores is limited to less than 109 million years in halite fluid inclusions, to 100 to 160 million years in the Martian subsurface below 3 m, and to less than 600,000 years in the upper-most meter of Mars.

  1. Fluid-inclusion technique for determining maximum temperature in calcite and its comparison to the vitrinite reflectance geothermometer

    USGS Publications Warehouse

    Barker, C.E.; Goldstein, R.H.

    1990-01-01

    The hypothesis that aqueous fluid inclusions in calcite can be used to establish maximum temperature (Tpeak) is tested. Fluid inclusion Th, mean random vitrinite reflectance (Rm), and present-day Tpeak from 46 diverse geologic systems that have been at Tpeak from 104 to 106 yr have been compiled. Present Tpeak ranged from 65 to 345??C, Th modes and means ranged from 59 to 350??C, and Rm data ranged from 0.4% to 4.6%, spanning the temperature and thermal maturity range associated with burial diagenesis, hydrothermal alteration, and low-grade metamorphism. Plots of Th and Tpeak data for systems thought to be currently at maximum temperature demonstrate close agreement between Th and present Tpeak in sedimentary basins. The relation suggests that Th of aqueous fluid inclusions in calcite may be a useful measure of maximum temperature. This study also compared Th to mean random vitrinite reflectance (Rm). Th correlates well with Rm and results in a curve similar to Rm vs. Tpeak calibrations determined by other workers. Strong correlation between Tpeak and Rm in these systems suggests that maximum temperature is the major control on thermal maturation. -after Authors

  2. The Donoso copper-rich, tourmaline-bearing breccia pipe in central Chile: petrologic, fluid inclusion and stable isotope evidence for an origin from magmatic fluids

    NASA Astrophysics Data System (ADS)

    Skewes, M. Alexandra; Holmgren, Carmen; Stern, Charles R.

    2003-01-01

    The copper-rich, tourmaline-bearing Donoso breccia pipe is one among more than 15 different mineralized breccias in the giant (>50 million metric tonnes of copper) Miocene and Pliocene Río Blanco-Los Bronces copper deposit in the high Andes of central Chile. This breccia pipe, bracketed in age between 5.2 and 4.9 Ma, has dimensions of 500 by 700 m at the current surface 3,670 m above sea level. Its roots have yet to be encountered, and it is >300 m in diameter at the depth of the deepest drill holes. The Donoso breccia is, for the most part, monolithic, containing clasts of the equigranular quartz monzonite pluton which hosts the pipe. It is matrix supported, with between 5 and 25% of the total rock volume consisting of breccia-matrix minerals, which include tourmaline, quartz, chalcopyrite, pyrite, specularite, and lesser amounts of bornite and anhydrite. An open pit mine, centered on this breccia pipe, has a current production of 50,000 tonnes of ore per day at an average grade of 1.2% copper, and copper grade in the breccia matrix is significantly higher. Measured δ18O for tourmaline and quartz from the matrix of the Donoso breccia at different levels of the pipe range from +6.9 to +12.0‰, and measured δD in tourmaline ranges from -73 to -95‰. Temperatures of crystallization of these minerals, as determined by the highest homogenization temperatures of highly saline fluid inclusions, range from 400 to >690°C. When corrected for these temperatures, the stable isotope data indicate that fluids from which these breccia-matrix minerals precipitated were magmatic, with δ18O between +5.6 to +9.1‰ and δD between -51 to -80‰. These isotopic data preclude participation of a significant amount of meteoric water in the formation of the Donoso breccia. They support a model in which brecciation is caused by expansion of magmatic fluids exsolved from a cooling pluton, and breccia-matrix minerals, including copper sulfides, precipitated from the same magmatic

  3. Ore genesis constraints on the Idaho cobalt belt from fluid inclusion gas, noble gas isotope, and ion ratio analyses--a reply

    USGS Publications Warehouse

    Hofstra, Albert H.; Landis, Gary P.

    2013-01-01

    Burlinson (2013) questions the veracity of the H2 concentrations reported for fluid inclusion extracts from minerals in the Idaho cobalt belt (Table 2; Landis and Hofstra, 2012) and suggests that they are an analytical artifact of electron-impact mass spectrometry. He also declares that H2 should not be present in fluid inclusions because it is invariably lost by diffusion and is never detected in fluid inclusions by laser Raman. We welcome this opportunity to reply and maintain that the reported H2 contents are accurate. Below we explain why Burlinson’s criticisms are invalid.

  4. Geology, mineralogy and fluid inclusion data of the Kizilcaören fluorite barite REE deposit, Eskisehir, Turkey

    NASA Astrophysics Data System (ADS)

    Gültekin, Ali Haydar; Örgün, Yüksel; Suner, Fikret

    2003-01-01

    The Kizilcaören fluorite-barite-Rare Earth Element (REE) deposit occurs as epithermal veins and breccia fillings in altered Triassic metasandstones and Oligocene-Miocene pyroclastics adjacent to alkaline porphyritic trachyte and phonolite. This deposit is the only commercial source of REE and thorium in Turkey. Most of the fluorite-barite-REE mineralisation at Kizilcaören has been formed by hydrothermal solutions, which are thought to be genetically associated with alkaline volcanism. The occurrence of the ore minerals in vuggy cavities and veins of massive and vuggy silica indicate that the ore stage postdates hydrothermal alteration. The deposit contains evidence of at least three periods of hypogene mineralisation separated by two periods of faulting. The mineral assemblage includes fluorite, barite, quartz, calcite, bastnäsite, phlogopite, pyrolusite and hematite as well as minor amounts of plagioclase feldspar, pyrite, psilomelane, braunite, monazite, fluocerite, brockite, goethite, and rutile. Fluid inclusion microthermometry indicates that the barite formed from low salinity (0.4-9.2 equiv. wt% NaCl) fluids at low temperatures, between 105 and 230 °C, but fluorite formed from slightly higher salinity (<12.4 equiv. wt% NaCl) fluids at low and moderate temperatures, between 135-354 °C. The depositional temperature of bastnäsite is between 143-286 °C. The local coexistence of liquid- and vapour-rich inclusions suggests boiling conditions. Many relatively low-salinity (<10.0 equiv. wt% NaCl), low and moderate temperature (200-300 °C) inclusions might be the result of episodic mixing of deep-saline brines with low-salinity meteoric fluids. The narrow range of δ34S (pyrite and barite) values (2.89-6.92‰ CDT)suggests that the sulphur source of the hydrothermal fluids are the same and compatible with a volcanogenic sulphate field derived from a magmatic sulphur source.

  5. Strain localization in brittle-ductile shear zones: fluid abundant vs fluid limited conditions (an example from Wyangala area, Australia)

    NASA Astrophysics Data System (ADS)

    Spruzeniece, L.; Piazolo, S.

    2015-04-01

    This study focuses on physiochemical processes occurring in a brittle-ductile shear zone at both fluid-present and fluid-limited conditions. In the studied shear zone (Wyangala, SE Australia), a coarse-grained two feldspar-quartz-biotite granite is transformed into a medium grained orthogneiss at the shear zone margins and a fine-grained quartz-muscovite phyllonite in the central parts. The orthogneiss displays cataclasis of feldspar and crystal-plastic deformation of quartz. Quartz accommodates most of the deformation and is extensively recrystallized showing distinct crystallographic preferred orientation (CPO). Feldspar-to-muscovite, biotite-to-muscovite and albitization reactions occur locally at porphyroclasts' fracture surfaces and margins. However, the bulk rock composition shows very little change in respect to the wall rock composition. In contrast, in the shear zone centre quartz occurs as large, weakly deformed porphyroclasts, in sizes similar to that in the wall rock, suggesting that it has undergone little deformation. Feldspars and biotite are almost completely reacted to muscovite, which is arranged in a fine-grained interconnected matrix. Muscovite-rich layers contain significant amounts of fine-grained intermixed quartz with random CPO. These domains are interpreted to have accommodated most of the strain. Bulk rock chemistry data shows a significant increase in SiO2 and depletion in NaO content compared to the wall rock composition. We suggest that the high and low strain fabrics represent markedly different scenarios and cannot be interpreted as a simple sequential development with respect to strain. We suggest that the fabrics and mineralogical changes in the shear zone centre have formed due to fluid influx probably along an initially brittle fracture. Here, hydration reactions dramatically changed the rheological properties of the rock. In the newly produced muscovite-quartz layers creep cavitation associated with grain boundary sliding and

  6. Formation conditions of leucogranite dykes and aplite-pegmatite dykes in the eastern Mt. Capanne plutonic complex (Elba, Italy): fluid inclusion studies in quartz, tourmaline, andalusite and plagioclase

    NASA Astrophysics Data System (ADS)

    Bakker, Ronald J.; Schilli, Sebastian E.

    2016-02-01

    Leucogranite and aplite-pegmatite dykes are associated with the Mt. Capanne pluton (Elba) and partly occur in the thermally metamorphosed host rock (serpentinites). Crystallization conditions of these dykes in the late magmatic-hydrothermal stage are estimated from fluid inclusion studies and mineralogical characterisation, obtained from detailed microthermometry, Raman spectroscopy, and electron microprobe analyses. Fluid inclusion assemblages are analysed in andalusite, quartz, and plagioclase from the leucogranite dykes, and in tourmaline and quartz from the aplite-pegmatite dykes. The fluid inclusion assemblages record multiple pulses of low salinity H2O-rich magmatic and reduced metamorphic fluid stages. Magmatic fluids are characterized by the presence of minor amounts of CO2 and H3BO3, whereas the metamorphic fluids contain CH4 and H2. The highly reduced conditions are also inferred from the presence of native arsenic in some fluid inclusions. Several fluid inclusion assemblages reveal fluid compositions that must have resulted from mixing of both fluid sources. In leucogranite dykes, magmatic andalusite contains a low-density magmatic CO2-rich gas mixture with minor amounts of CH4 and H2. Accidentally trapped crystals (mica) and step-daughters (quartz and diaspore) are detected in some inclusions in andalusite. The first generation of inclusions in quartz that crystallized after andalusite contains a highly reduced H2O-H2 mixture and micas. The second type of inclusions in quartz from the leucogranite is similar to the primary inclusion assemblage in tourmaline from the aplite-pegmatite, and contains up to 4.2 mass% H3BO3, present as a sassolite daughter crystal or dissolved ions, in addition to a CO2-CH4 gas mixture, with traces of H2, N2, H2S, and C2H6. H2O is the main component of all these fluids ( x = 0.91 to 0.96) with maximally 7 mass% NaCl. Some accidentally trapped arsenolite and native arsenic are also detected. These fluids were trapped in the

  7. A new technique for surface and shallow subsurface paleobarometry using fluid inclusions: An example from the Upper Ordovician Viola Formation, Kansas, USA

    USGS Publications Warehouse

    Newell, K.D.; Goldstein, R.H.

    1999-01-01

    This research illustrates a new approach for paleobarometry employing heterogeneously entrapped fluid inclusions to determine timing and depth of diagenesis. Heterogeneously entrapped fluid inclusions (gas + water) in vug-filling quartz from the Upper Ordovician Viola Formation in the Midcontinent of the United States were analyzed for their internal pressure with a fluid-inclusion crushing stage. The free gas in fluid inclusions was entrapped at near-surface temperature, as indicated by the presence of all-liquid fluid inclusions and fluid inclusions with low homogenization temperatures ( <40??C). Crushing the crystal and measuring the change in bubble size determines the pressure of entrapment directly. Heterogeneous trapping is indicated by widely varying L:V ratios, from all-liquid to vapor-rich. Gas bubbles in most fluid inclusions analyzed expanded upon release to atmospheric pressure, but some collapsed. A mode of 1.5 to 2.0 atm internal pressure was indicated by the crushing runs, but pressures up to 42.9 atm were recorded. Quartz precipitation and associated fluid-inclusion entrapment therefore occurred over a wide depth-range, but principally at depths of approximately 10 m. Crushing runs done in kerosene confirmed the presence of hydrocarbon gases in most of these inclusions, and bulk analyses of gases in the quartz by quadrupole mass spectrometer revealed methane, ethane, and atmospheric gases. The hydrocarbon gases may have originated in deeper thermogenically mature sedimentary strata, and then leaked to the near-surface where they were entrapped in the precipitating quartz cement. Freezing data indicate an event of quartz precipitation from fluids of marine-fresh water intermediate salinity and other events of precipitation from more saline fluids. Considering the determined pressures, the precipitating fluids probably originated at surfaces of subaerial exposure (unconformities) and surfaces of evaporite precipitation in the overlying Silurian

  8. Exhumation history of a shear zone constrained by microstructural and fluid inclusion techniques: an example from the Satluj valley, NW Himalaya, India

    NASA Astrophysics Data System (ADS)

    Pandey, Anand K.; Sachan, H. K.; Virdi, N. S.

    2004-07-01

    The regional structures, rock microstructures and fluid inclusion trail patterns have been employed to determine the evolution of the Jakhri Thrust Zone (JTZ). The JTZ is a break back thrust cutting across the folded Lesser Himalayan Crystalline nappe and is best exposed in the Kulu-Rampur window zone of the NW Himalaya. The microstructures in the JTZ suggest SW directed ductile shearing and a progressively decreasing finite strain away from the thrust in the footwall. The quartz recrystallization, microstructures and presence of chlorite in the thrust zone indicate lower greenschist facies P-T conditions during deformation. The microstructures and fluid inclusion trails (secondary) show analogous patterns suggesting that the latter would have formed by the healing of microfractures during shearing in the footwall. The microthermic studies on these fluid inclusions suggest that the CO 2-H 2O inclusions have been emplaced and reequilibrated during peak deformation whereas the H 2O-NaCl inclusions reequilibrated during footwall exhumation. The density and salinity of fluid inclusions were also reset during the same exhumation. The isochores of CO 2-H 2O and H 2O-NaCl inclusions in the greenschist facies suggest an isothermal exhumation path from a depth of ˜15 to 17 km, assuming lithostatic pressure conditions. These results in the JTZ emphasize the utility of fluid inclusions in tectonic studies.

  9. New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

    NASA Astrophysics Data System (ADS)

    Affolter, S.; Fleitmann, D.; Leuenberger, M.

    2014-07-01

    A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us simultaneously to measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the online water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δ D robustness. To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 °C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water, resulting in an artificial water background with well-known δ D and δ18O values. The speleothem sample is placed in a copper tube, attached to the line, and after system stabilisation it is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements, a syringe injection unit was added to the line. Peak evaluation is done similarly as in gas chromatography to obtain &delta D; and δ18O isotopic compositions of measured water aliquots. Precision is better than 1.5 ‰ for δ D and 0.4 ‰ for δ18O for water measurements for an extended range (-210 to 0 ‰ for δ D and -27 to 0 ‰ for δ18O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to the isotope ratio mass

  10. New on-line method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

    NASA Astrophysics Data System (ADS)

    Affolter, S.; Fleitmann, D.; Leuenberger, M.

    2014-01-01

    A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us to simultaneously measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the on-line water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δD reliability. To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 °C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water resulting in an artificial water background with well-known δD and δ18O values. The speleothem sample is placed into a copper tube, attached to the line and after system stabilisation is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements a syringe injection unit was added to the line. Peak evaluation is done similarly as in gas chromatography to obtain δD and δ18O isotopic composition of measured water aliquots. Precision is better than 1.5‰ for δD and 0.4‰ for δ18O for water measurement for an extended range (-210 to 0‰ for δD and -27 to 0‰ for δ18O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to Isotope Ratio Mass Spectrometry (IRMS) technique.

  11. Fluid inclusion from drill hole DW-5, Hohi geothermal area, Japan: Evidence of boiling and procedure for estimating CO2 content

    USGS Publications Warehouse

    Sasada, M.; Roedder, E.; Belkin, H.E.

    1986-01-01

    Fluid inclusion studies have been used to derive a model for fluid evolution in the Hohi geothermal area, Japan. Six types of fluid inclusions are found in quartz obtained from the drill core of DW-5 hole. They are: (I) primary liquid-rich with evidence of boiling; (II) primary liquid-rich without evidence of boiling; (III) primary vapor-rich (assumed to have been formed by boiling); (IV) secondary liquid-rich with evidence of boiling; (V) secondary liquid-rich without evidence of boiling; (VI) secondary vapor-rich (assumed to have been formed by boiling). Homogenization temperatures (Th) range between 196 and 347??C and the final melting point of ice (Tm) between -0.2 and -4.3??C. The CO2 content was estimated semiquantitatively to be between 0 and 0.39 wt. % based on the bubble behavior on crushing. NaCl equivalent solid solute salinity of fluid inclusions was determined as being between 0 and 6.8 wt. % after minor correction for CO2 content. Fluid inclusions in quartz provide a record of geothermal activity of early boiling and later cooling. The CO2 contents and homogenization temperatures of fluid inclusions with evidence of boiling generally increase with depth; these changes, and NaCl equivalent solid solute salinity of the fluid can be explained by an adiabatic boiling model for a CO2-bearing low-salinity fluid. Some high-salinity inclusions without CO2 are presumed to have formed by a local boiling process due to a temperature increase or a pressure decrease. The liquid-rich primary and secondary inclusions without evidence of boiling formed during the cooling process. The salinity and CO2 content of these inclusions are lower than those in the boiling fluid at the early stage, probably as a result of admixture with groundwater. ?? 1986.

  12. Origin of REE-rich ferrocarbonatites in southern Siberia (Russia): implications based on melt and fluid inclusions

    NASA Astrophysics Data System (ADS)

    Prokopyev, Ilya R.; Borisenko, Alexander S.; Borovikov, Andrey A.; Pavlova, Galina G.

    2016-06-01

    Fe-rich carbonatites with a mineral assemblage of ankerite-calcite or siderite are widespread in southern Siberia, Russia. The siderite carbonatites are associated with F-Ba-Sr-REE mineralization and have a 40Ar/39Ar age of 117.2 ± 1.3 Ma. Melt and fluid inclusions suggest that the carbonatites formed from volatile-rich alkali- and chloride-bearing carbonate melts. Ankerite-calcite carbonatites formed from carbonatite melt at a temperature of more than 790 °C. The ferrocarbonatites (the second phase of carbonatite intrusion) formed from a sulfate-carbonate-chloride fluid phase (brine-melt) at >650 °C and ≥360 MPa. The brine-melt fluid phase had high concentrations of Fe and LREEs. A subsequent hydrothermal overprint contributed to the formation of economically important barite-Sr-fluorite-REE mineralization in polymict siderite breccia.

  13. Fluid inclusion and noble gas studies of the Dongping gold deposit, Hebei Province, China: A mantle connection for mineralization?

    USGS Publications Warehouse

    Mao, J.; Li, Y.; Goldfarb, R.; He, Y.; Zaw, K.

    2003-01-01

    The Dongping gold deposit (>100 t Au) occurs about 200 km inboard of the northern margin of the North China craton. The deposit is mainly hosted by syenite of a middle Paleozoic alkalic intrusive complex that was emplaced into Late Archean basement rocks. Both groups of rocks are intruded by Late Jurassic to Early Cretaceous crustal-melt granite dikes and stocks, some within a few kilometers of the deposit. The gold ores were deposited during this latter magmatic period at about 150 Ma, a time that was characterized by widespread regional north-south compression that formed the east-west-trending Yanshan deformational belt. The ores include both the telluride mineral-bearing, low sulfide quartz veins and the highly K-feldspar-altered syenite, with most of the resource concentrated in two orebodies (1 and 70). Fluid inclusion microthermometry indicates heterogeneous trapping of low-salinity (e.g., 5-7 wt % NaCl equiv) fluids that varied from a few to 60 mole percent nonaqueous volatile species. Laser Raman spectroscopy confirms that the vapor phase in these inclusions is dominated by CO2, but may be comprised of as much as 9 mole percent H2S and 20 mole percent N2; methane concentrations in the vapor phase are consistently <1 mole percent. The variable phase ratios are consistent with fluid immiscibility during ore formation. Fluid inclusion trapping conditions are estimated to be 250?? to 375??C and 0.6 to 1.0 kbar. Helium isotope studies of fluid inclusions in ore-stage pyrites indicate He/He ratios of 2.1 to 5.2 Ra (Ra = 1.4 x 10-6 for air) for orebody 1 and 0.3 to 0.8 Ra for orebody 70. The former data suggest that at least 26 to 65 percent mantle helium occurs in the fluids that deposited the veins in orebody 1. The lower values for orebody 70, which is characterized by a more disseminated style of gold mineralization, are interpreted to reflect an increased interaction of ore fluids with surrounding crustal rocks, which may have contributed additional He to

  14. Stable isotope and fluid inclusion studies of carbonate deposits from the Tolfa Mountains mining district (Latium, central Italy)

    USGS Publications Warehouse

    Masi, U.; Ferrini, V.; O'Neil, J.R.; Batchelder, J.N.

    1980-01-01

    Carbon and oxygen isotope analyses were made of representative samples of calcite and quartz from the carbonate deposits in the Tolfa Mountains mining district. Measurements were also made of hydrogen isotope compositions, filling temperatures and salinities of fluid inclusions in these minerals. There are three stages of mineralization at Tolfa. In stage I, characterized by calc-silicate hornfels, the carbonates have relatively high ?? 18O values of 14.5 to 21.6 suggesting a rather low water/rock ratio. ??13C values of -0.3 to 2.1 indicate that appreciable decarbonation or introduction of deep-seated carbon did not occur. Stage II is marked by phanerocrystalline carbonates; ?? 18O values of 13.1 to 20.0 and ??13C values of 0.7 to 5.0 identify them as hydrothermal veins rather than marbles. ?? D values of -56 to -50 for inclusion fluids suggest a possible magmatic component to the hydrothermal fluid. Filling temperatures of coarse-grained samples of Calcite II are 309?? to 362?? C with a salinity range of 5.3 to 7.1 weight percent NaCl. Calculated ??18O values of 11-12 for these fluids are again indicative of low water/rock ratios. The sparry calcites of stage III have ??18O and ??13C values of 8.1 to 12.9 and -1.7 to 3.2, respectively. ?? D values of inclusion fluids are -40 to -33, clearly heavier than in earlier stages and similar to values of modern local ground waters. A salinity measurement of <0.1 weight percent NaCl in a sample of Calcite III is compatible with a relatively unaltered ground water origin for this fluid. Precipitation of the sparry calcite took place at much lower temperatures, around 160?? C. For quartz, ??18O values of 9.3 to 12.4 and ?? D values for inclusions of -53 to -28 are consistent with its late occurrence and paragenetic link with associated carbonates. ?? 1980 Springer-Verlag.

  15. Seawater fluid inclusions preserved within Cambrian-Ordovician marine cements indicate Cambrian-Ordovician seawater precipitated low-magnesium calcite

    SciTech Connect

    Johnson, W.J.; Goldstein, R.H. . Dept. of Geology)

    1992-01-01

    The San Saba Member of the Wilberns Formation (Llano Uplift, Texas) contains a series of Late Cambrian-Early Ordovician hardgrounds. Bladed low-Mg calcite cements are truncated at hardground surfaces and overlain by shallow marine limestones, indicating a syndepositional shallow marine origin. Primary one-phase fluid inclusions within bladed cements have marine salinities, suggesting that these low-Mg calcite cements formed as a precipitate from Late Cambrian and Early Ordovician seawater and have not undergone recrystallization. Stable isotope analysis of the bladed cement yields delta O-18 values that cluster between [minus]5.6--[minus]6.0 ([per thousand] PDB) which is comparable to those previously reported for Early Ordovician marine calcite. The delta C-13 values are more positive than those reported for this time interval (0.6--1.3 [per thousand] PDB). Trace element analysis indicates that strontium content ranges from 200 to 2,200 ppm. Iron ranges from below detection by electron microprobe to 800 ppm. Mg is generally below detection, however, cements in one hardground display Mg contents that increase progressively toward pore centers. Trace element data lack covariance that would suggest recrystallization. In addition, closed system recrystallization cannot be supported here due to a lack of microdolomite inclusions. Stable isotope, trace element, and fluid inclusion data are consistent with submarine cementation at or below the sediment-water interface. These cements have not undergone significant recrystallization and preserve a primary low Mg calcite mineralogy. These data suggest that early Paleozoic seawater differed chemically from modern seawater. Moreover, preservation of ancient seawater, within fluid inclusions, may provide a direct means of determining those differences.

  16. Magma evolution and the formation of porphyry Cu Au ore fluids: evidence from silicate and sulfide melt inclusions

    NASA Astrophysics Data System (ADS)

    Halter, Werner E.; Heinrich, Christoph A.; Pettke, Thomas

    2005-03-01

    Silicate and sulfide melt inclusions from the andesitic Farallón Negro Volcanic Complex in NW Argentina were analyzed by laser ablation ICPMS to track the behavior of Cu and Au during magma evolution, and to identify the processes in the source of fluids responsible for porphyry-Cu-Au mineralization at the 600 Mt Bajo de la Alumbrera deposit. The combination of silicate and sulfide melt inclusion data with previously published geological and geochemical information indicates that the source of ore metals and water was a mantle-derived mafic magma that contained approximately 6 wt.% H2O and 200 ppm Cu. This magma and a rhyodacitic magma mixed in an upper-crustal magma chamber, feeding the volcanic systems and associated subvolcanic intrusions over 2.6 million years. Generation of the ore fluid from this magma occurred towards the end of this protracted evolution and probably involved six important steps: (1) Generation of a sulfide melt upon magma mixing in some parts of the magma chamber. (2) Partitioning of Cu and Au into the sulfide melt (enrichment factor of 10,000 for Cu) leading to Cu and Au concentrations of several wt.% or ppm, respectively. (3) A change in the tectonic regime from local extension to compression at the end of protracted volcanism. (4) Intrusion of a dacitic magma stock from the upper part of the layered magma chamber. (5) Volatile exsolution and resorption of the sulfide melt from the lower and more mafic parts of the magma chamber, generating a fluid with a Cu/Au ratio equal to that of the precursor sulfide. (6) Focused fluid transport and precipitation of the two metals in the porphyry, yielding an ore body containing Au and Cu in the proportions dictated by the magmatic fluid source. The Cu/S ratio in the sulfide melt inclusions requires that approximately 4,000 ppm sulfur is extracted from the andesitic magma upon mixing. This exceeds the solubility of sulfide or sulfate in either of the silicate melts and implies an additional source

  17. Metamorphic fluid flow in the northeastern part of the 3.8 3.7 Ga Isua Greenstone Belt (SW Greenland): A re-evalution of fluid inclusion evidence for early Archean seafloor-hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Heijlen, Wouter; Appel, Peter W. U.; Frezzotti, Maria-Luce; Horsewell, Andy; Touret, Jacques L. R.

    2006-06-01

    Fluid inclusions in quartz globules and quartz veins of a 3.8-3.7 Ga old, well-preserved pillow lava breccia in the northeastern Isua Greenstone Belt (IGB) were studied using microthermometry, Raman spectrometry and SEM Cathodoluminescence Imaging. Petrographic study of the different quartz segregations showed that they were affected by variable recrystallization which controlled their fluid inclusion content. The oldest unaltered fluid inclusions found are present in vein crystals that survived dynamic and static recrystallization. These crystals contain a cogenetic, immiscible assemblage of CO 2-rich (+H 2O, +graphite) and brine-rich (+CO 2, +halite, +carbonate) inclusions. The gas-rich inclusions have molar volumes between 44.8 and 47.5 cm 3/mol, while the brine inclusions have a salinity of ˜33 eq. wt% NaCl. Modeling equilibrium immiscibility using volumetric and compositional properties of the endmember fluids indicates that fluid unmixing occurred at or near peak-metamorphic conditions of ˜460 °C and ˜4 kbar. Carbonate and graphite were precipitated cogenetically from the physically separated endmember fluids and were trapped in fluid inclusions. In most quartz crystals, however, recrystallization obliterated such early fluid inclusion assemblages and left graphite and carbonate as solid inclusions in recrystallized grains. Intragranular fluid inclusion trails in the recrystallized grains of breccia cementing and crosscutting quartz veins have CO 2-rich assemblages, with distinctly different molar volumes (either between 43.7 and 47.5 cm 3/mol or between 53.5 and 74.1 cm 3/mol), and immiscible, halite-saturated H 2O-CO 2-NaCl(-other salt) inclusions. Later intergranular trails have CH 4-H 2 ( X up to ˜0.3) inclusions of variable density (ranging from 48.0 to >105.3 cm 3/mol) and metastable H 2O-NaCl(-other salt?) brines (˜28 eq. wt% NaCl). Finally, the youngest fluid inclusion assemblages are found in non-luminescent secondary quartz and contain low

  18. Thermal history of the Mississippian-Pennsylvanian boundary at Arrow Canyon, NV, USA: Insights from carbonate clumped isotopes and fluid inclusion microthermometry

    NASA Astrophysics Data System (ADS)

    Shenton, B.; Grossman, E. L.; Passey, B. H.; Henkes, G. A.; Becker, S. P.; Pottorf, R. J.

    2013-12-01

    Constraining the temperature-time history of sedimentary basins is critical for understanding basin evolution and related problems, such as petroleum systems analysis and genesis of metallic ore deposits. The importance of burial history studies is confirmed by the abundance and diversity of techniques aimed at acquiring thermal history information. Often, multiple techniques are required to fully characterize sediment thermal histories because each tool targets different burial temperatures (e.g., maximum burial temperature, T-t points, or cooling rates) and different indicators may be limited by suitable study material or geologic setting. Therefore it is important to test new techniques, such as clumped isotopes, that may aid in reconstructing basin thermal histories. The potential utility of clumped isotopes as a thermal history tool is suggested by the observation of elevated clumped isotope temperatures in nominally well-preserved fossils, and also from recent laboratory heating experiments showing that C-O bonds can reorder in the solid-state during heating. While this phenomenon conceals primary paleoclimate information, it may record burial temperatures useful for constraining basin thermal histories. Here we present clumped isotope measurements from brachiopods, crinoids, diagenetic cements, and bulk matrix material collected from within ~ 50 m of the global stratotype section and point (GSSP) for the Mississippian-Pennsylvanian boundary along with new fluid inclusion microthermometry data. Preliminary clumped isotope temperatures range from ~100-165 °C and generally cluster based on component type. Secondary fluid inclusion assemblages in blocky calcite cement indicate that strata surrounding the GSSP experienced at least 175-180 °C during burial in the Antler foreland basin. The fact that clumped isotope temperatures in all carbonate components are lower than independently constrained peak temperature estimates from fluid inclusions suggests that

  19. A salt diapir-related Mississippi Valley-type deposit: The Bou Jaber Pb-Zn-Ba-F deposit, Tunisia: Fluid inclusion and isotope study

    USGS Publications Warehouse

    Bouhlel, Salah; Leach, David; Johnson, Craig A.; Marsh, Erin; Salmi-Laouar, Sihem; Banks, David A.

    2016-01-01

    The Bou Jaber Ba-F-Pb-Zn deposit is located at the edge of the Bou Jaber Triassic salt diapir in the Tunisia Salt Diapir Province. The ores are unconformity and fault-controlled and occur as subvertical column-shaped bodies developed in dissolution-collapse breccias and in cavities within the Late Aptian platform carbonate rocks, which are covered unconformably by impermeable shales and marls of the Fahdene Formation (Late Albian–Cenomanian age). The host rock is hydrothermally altered to ankerite proximal to and within the ore bodies. Quartz, as fine-grained bipyramidal crystals, formed during hydrothermal alteration of the host rocks. The ore mineral assemblage is composed of barite, fluorite, sphalerite, and galena in decreasing abundance. The ore zones outline distinct depositional events: sphalerite-galena, barite-ankerite, and fluorite. Fluid inclusions, commonly oil-rich, have distinct fluid salinities and homogenization temperatures for each of these events: sphalerite-galena (17 to 24 wt% NaCl eq., and Th from 112 to 136 °C); ankerite-barite (11 to 17 wt% NaCl eq., and Th from 100 to 130 °C); fluorite (19 to 21 wt% NaCl eq., Th from 140 to 165 °C). The mean temperature of the ore fluids decreased from sphalerite (125 °C) to barite (115 °C) and increased during fluorite deposition (152 °C); then decreased to ∼110 °C during late calcite precipitation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of fluid inclusions in fluorite are metal rich (hundreds to thousands ppm Pb, Zn, Cu, Fe) but the inclusions in barite are deficient in Pb, Zn, Cu, Fe. Inclusions in fluorite have Cl/Br and Na/Br ratios of several thousand, consistent with dissolution of halite while the inclusions analysed in barite have values lower than seawater which are indicative of a Br-enriched brine derived from evaporation plus a component of halite dissolution. The salinity of the barite-hosted fluid inclusions is less than obtained

  20. An odorant-binding protein is abundantly expressed in the nose and in the seminal fluid of the rabbit.

    PubMed

    Mastrogiacomo, Rosa; D'Ambrosio, Chiara; Niccolini, Alberto; Serra, Andrea; Gazzano, Angelo; Scaloni, Andrea; Pelosi, Paolo

    2014-01-01

    We have purified an abundant lipocalin from the seminal fluid of the rabbit, which shows significant similarity with the sub-class of pheromone carriers "urinary" and "salivary" and presents an N-terminal sequence identical with that of an odorant-binding protein (rabOBP3) expressed in the nasal tissue of the same species. This protein is synthesised in the prostate and found in the seminal fluid, but not in sperm cells. The same protein is also expressed in the nasal epithelium of both sexes, but is completely absent in female reproductive organs. It presents four cysteines, among which two are arranged to form a disulphide bridge, and is glycosylated. This is the first report of an OBP identified at the protein level in the seminal fluid of a vertebrate species. The protein purified from seminal fluid is bound to some organic chemicals whose structure is currently under investigation. We reasonably speculate that, like urinary and salivary proteins reported in other species of mammals, this lipocalin performs a dual role, as carrier of semiochemicals in the seminal fluid and as detector of chemical signals in the nose. PMID:25391153

  1. Strong salinity gradients in the northeastern part of the Salton Sea geothermal field, CA: a fluid inclusion and brine chemistry study

    SciTech Connect

    Oakes, C.S.

    1985-01-01

    Geothermal wells in the northeastern Salton Sea geothermal field produce concentrated Na-Ca-K-Cl brines. Maximum dissolved constituents do not exceed 260,000 ppm. Fluid inclusion homogenization temperatures from cuttings of vein calcite and quartz are in close agreement with temperature logs and indicate maximum reservoir temperatures between 290/sup 0/ and 310/sup 0/C at 3140 to 3565 m. Melting temperatures of inclusion fluids indicate the trapping of both low salinity and high salinity vein-forming solutions. The high salinity inclusion fluids appear similar to the produced reservoir fluids in their total dissolved solids, while both high salinity and low salinity inclusions imply temperatures similar to that of the reservoir. The low salinity inclusions occur over broad intervals above and below the much less vertically extensive high salinity inclusion fluids. Although the presence of interstratified high salinity and low salinity brines should be gravitationally unstable, flow tests of one well, at varying well head pressures, produced two brines of distinctly different compositions. Consequently, the persistence of two different brines requires severe impedance of vertical permeability. Stratification of brines in this geothermal system carries significant implications for the formation models of some epithermal ore deposits by mixing of fluids of different salinity, pH, fO/sub 2/, fS/sub 2/, temperature, etc. Additionally, there are very strong economic advantages to the possible production of hot, dilute brines rather than the currently produced highly saline brines.

  2. Synthetic fluid inclusions XIX. Experimental determination of the vapor-saturated liquidus of the system H2O-NaCl-FeCl2

    NASA Astrophysics Data System (ADS)

    Lecumberri-Sanchez, Pilar; Steele-MacInnis, Matthew; Bodnar, Robert J.

    2015-01-01

    Magmatic-hydrothermal fluids associated with felsic to intermediate composition magmas are generally dominated by (Na ± K)Cl, but often the fluids also contain significant concentrations of FeCl2. Previously, fluid inclusions containing such fluids were interpreted using the properties of H2O-NaCl because the effect of FeCl2 on the phase equilibrium and volumetric (PVTx) properties of aqueous fluids was essentially unknown. In this study, synthetic fluid inclusion experiments have been conducted to determine the vapor-saturated liquidus phase relations of the system H2O-NaCl-FeCl2. Microthermometric and microanalytical measurements on synthetic fluid inclusions have been combined with the limited existing data, as well as with predictions based on Pitzer's formalism, to determine the ternary cotectic and peritectic phase boundaries and liquidus fields. The liquidus is qualitatively similar to those of other ternary systems of H2O-NaCl plus divalent-cation chlorides (MgCl2 and CaCl2) and has been characterized through empirical equations that represent the liquid salinity on the ice- and halite-liquidus surfaces. The ice and halite liquidi intersect at a metastable cotectic curve, which can be used to determine fluid compositions in this system if metastable behavior is observed. Furthermore, based on the experimentally determined liquidus, bulk salinities of natural fluid inclusions can be determined from the last dissolution temperatures of ice and/or halite using the new empirical equations.

  3. Orientation, composition, and entrapment conditions of fluid inclusions in the footwall of the northern Snake Range detachment, Nevada

    NASA Astrophysics Data System (ADS)

    Carter, Matthew J.; Siebenaller, Luc; Teyssier, Christian

    2015-12-01

    Footwall rocks of the northern Snake Range detachment fault (Hampton and Hendry's Creeks) offer exposures of quartzite mylonites (sub-horizontal foliation) that were permeated by surface fluids. An S-C-C‧ mylonitic fabric is defined by dynamically recrystallized quartz and mica. Electron backscatter diffraction analyses indicate a strong preferred orientation of quartz that is overprinted by two sets of sub-vertical, ESE and NNE striking fractures. Analyses of sets of three perpendicular thin sections indicate that fluid inclusions (FIs) are arranged according to macroscopic fracture patterns. FIs associated with NNE and ESE-striking fractures coevally trapped unmixed CO2 and H2O-rich fluids at conditions near the critical CO2-H2O solvus, giving minimum trapping conditions of T = 175-200 °C and ˜100 MPa H2O-rich FIs trapped along ESE-trending microcracks in single crystals of quartz may have been trapped at conditions as low as 150 °C and 50 MPa indicating the latest microfracturing and annealing of quartz in an overall extensional system. Results suggest that the upper crust was thin (4-8 km) during FI trapping and had an elevated geotherm (>50 °C/km). Footwall rocks that have been exhumed through the brittle-ductile transition in such extensional systems experience both brittle and crystal-plastic deformation that may allow for circulation of meteoric fluids and grain-scale fluid-rock interactions.

  4. Stable isotope composition of fluid inclusions preserved in halite derived from Wieliczka and Bochnia Salt Beds (Southern Poland)

    NASA Astrophysics Data System (ADS)

    Dulinski, Marek; Rozanski, Kazimierz; Bukowski, Krzysztof

    2010-05-01

    Halite deposits located in the southern Poland, near Krakow, are famous mostly due to the medieval salt mine located in Wieliczka. Contrary to most salt deposits in Europe forming large domes, the halite deposits near Krakow form distinct beds, extending from west to east on the area of ca. 10 km2, with several types of salt identified. The deposits were formed in shallow environment, ca. 15 mln years ago and represent initial stages of Miocene sea water evaporation. Stable isotope composition of fluid inclusions trapped in the halite crystals originating from Wieliczka and Bochnia salt mines was investigated. Three distinct groups of samples were analysed: (i) samples derived from so-called 'green salt' beds forming extensive horizontal structures, (ii) samples derived from so-called zuber-type salt, and (iii) large monocrystals of halite collected in two crystal caves existing in the mine. The samples belonging to the first and second group were heated under vacuum to extract the fluid inclusions, according to the procedure used previously to extract inclusions from speleothem samples. The macro-inclusions present in some monocrystals of halite collected in crystal caves were removed for analysis without any thermal treatment. The concentration of bivalent cations (Ca2+, Mg2+) was measured in the bulk material (green salt). K+, Mg2+ and SO4-2 content was measured in the fluid inclusions derived from macro-crystals. The stable isotope data points form two clusters in the δ2H-δ18O space, representing crystal caves and green- and zuber-type salts, respectively. The cluster representing green- and zuber-type salt deposit is shifted to the right-hand side of the Local Meteoric Water Line (LMWL), towards more positive δ2H and δ18O values, pointing to evaporative conditions during formation of these deposits. Although the evaporation trajectories for the sea water in the δ2H - δ18O space suggest that fluid inclusions might represent remnants of the original

  5. Mineralogic, fluid inclusion, and sulfur isotope evidence for the genesis of Sechangi lead-zinc (-copper) deposit, Eastern Iran

    NASA Astrophysics Data System (ADS)

    Malekzadeh Shafaroudi, Azadeh; Karimpour, Mohammad Hassan

    2015-07-01

    The Sechangi lead-zinc (-copper) deposit lies in the Lut block metallogenic province of Eastern Iran. This deposit consists of ore-bearing vein emplaced along fault zone and hosted by Late Eocene monzonite porphyry. Hydrothermal alteration minerals developed in the wall rock include quartz, kaolinite, illite, and calcite. Microscopic studies reveal that the vein contains galena and sphalerite with minor chalcopyrite and pyrite as hypogene minerals and cerussite, anglesite, covellite, malachite, hematite, and goethite as secondary minerals. Fluorite and quartz are the dominant gangue minerals and show a close relationship with sulfide mineralization. Calculated δ34S values for the ore fluid vary between -9.9‰ and -5.9‰. Sulfur isotopic compositions suggest that the ore-forming aqueous solutions were derived from magmatic source and mixed with isotopically light sulfur, probably leached from the volcanic and plutonic country rocks. Microthermometric study of fluid inclusions indicates homogenization temperatures of 151-352 °C. Salinities of ore-forming fluids ranged from 0.2 to 16.5 wt.% NaCl equivalent. The ore-forming fluids of the Sechangi deposit are medium- to low-temperature and salinity. Fluid mixing may have played an important role during Pb-Zn (-Cu) mineralization. The key factors allowing for metal transport and precipitation during ore formation include the sourcing of magmatic fluids with high contents of metallogenic elements and the mixing of these hydrothermal fluids with meteoric waters resulting in the formation of deposit. In terms of the genetic type of deposit, the Sechangi is classified as a volcanic-subvolcanic hydrothermal-related vein deposit.

  6. Composition of primary fluid and melt inclusions in regenerated olivines from hypabyssal kimberlites of the Malokuonapskaya pipe (Yakutia)

    NASA Astrophysics Data System (ADS)

    Tomilenko, A. A.; Kuzmin, D. V.; Bulbak, T. A.; Timina, T. Yu.; Sobolev, N. V.

    2015-11-01

    The primary fluid and melt inclusions in regenerated zonal crystals of olivine from kimberlites of the Malokuonapskaya pipe were first examined by means of microthermometry, optic and scanning electron microscopy, and Raman spectroscopy. The high-pressure genesis of homogenous central parts of the olivines was revealed, probably under intense metasomatism at early hypogene stages with subsequent regeneration in the kimberlitic melt. The olivine crystals were regenerated from silicate-carbonate melts at about 1100°C. The composition of the kimberlitic melt was changed by way of an increase in the calcium content.

  7. A new method of reconstituting the P-T conditions of fluid circulation in an accretionary prism (Shimanto, Japan) from microthermometry of methane-bearing aqueous inclusions

    NASA Astrophysics Data System (ADS)

    Raimbourg, Hugues; Thiéry, Régis; Vacelet, Maxime; Ramboz, Claire; Cluzel, Nicolas; Le Trong, Emmanuel; Yamaguchi, Asuka; Kimura, Gaku

    2014-01-01

    In paleo-accretionary prisms and the shallow metamorphic domains of orogens, circulating fluids trapped in inclusions are commonly composed of a mixture of salt water and methane, producing two types of fluid inclusions: methane-bearing aqueous and methane-rich gaseous fluid inclusions. In such geological settings, where multiple stages of deformation, veining and fluid influx are prevalent, textural relationships between aqueous and gaseous inclusions are often ambiguous, preventing the microthermometric determination of fluid trapping pressure and temperature conditions. To assess the P-T conditions of deep circulating fluids from the Hyuga unit of the Shimanto paleo-accretionary prism on Kyushu, Japan, we have developed a new computational code, applicable to the H2O-CH4-NaCl system, which allows the characterization of CH4-bearing aqueous inclusions using only the temperatures of their phase transitions estimated by microthermometry: Tmi, the melting temperature of ice; Thyd, the melting temperature of gas hydrate and Th,aq, homogenization temperature. This thermodynamic modeling calculates the bulk density and composition of aqueous inclusions, as well as their P-T isochoric paths in a P-T diagram with an estimated precision of approximatively 10%. We use this computational tool to reconstruct the entrapment P-T conditions of aqueous inclusions in the Hyuga unit, and we show that these aqueous inclusions cannot be cogenetic with methane gaseous inclusions present in the same rocks. As a result, we propose that pulses of a high-pressure, methane-rich fluid transiently percolated through a rock wetted by a lower-pressure aqueous fluid. By coupling microthermometric results with petrological data, we infer that the exhumation of the Hyuga unit from the peak metamorphic conditions was nearly isothermal and ended up under a very hot geothermal gradient. In subduction or collision zones, modeling aqueous fluid inclusions in the ternary H2O-CH4-NaCl system and not

  8. Concentration of ore elements in magmatic melts and natural fluids as deduced from data on inclusions in minerals

    NASA Astrophysics Data System (ADS)

    Naumov, V. B.; Girnis, A. V.; Dorofeeva, V. A.; Kovalenker, V. A.

    2016-07-01

    Based on intergration of the published data on composition of inclusions in minerals and quenched glasses, the mean concentrations of 24 ore elements have been calculated for magmatic silicate melts formed in main geodynamic settings of the Earth and in natural fluids. The mean glass compositions normalized to the primitive mantle correlate with the partition coefficient between olivine and the basic melt. It is established that the degree of enrichment in ore elements depending on geodynamic setting is controlled by various contribution of fluids to the element transfer and accumulation. The ratios of element contents in each geodynamic setting to the mean concentrations of elements over all settings in the Earth have been calculated.

  9. Chemical variations of mineral inclusions in Neoproterozoic high-Cr chromitites from Egypt: Evidence of fluids during chromitite genesis

    NASA Astrophysics Data System (ADS)

    Khedr, Mohamed Zaki; Arai, Shoji

    2016-01-01

    This paper details the mode of occurrence, petrography, and chemistry of mineral inclusions hosted in chromian spinels of the Neoproterozoic chromitites in the Southern Eastern Desert of Egypt. Neoproterozoic podiform chromitites from the Arais, Balamhindit, and Abu Dahr areas, in the Southern Eastern Desert, can be texturally and chemically classified into two main types: primary high-Al (spinel Cr# < 0.67) and high-Cr (spinel Cr# > 0.75) chromitites. The former, being free of primary-mineral inclusions, was crystallized mainly from the MORB-like tholeiitic melt generated during proto-forearc spreading at the initiation of subduction, whereas the latter was formed from boninitic melts resulting from the high-degree melting of the sub-arc depleted mantle in the presence of slab-derived fluids at a mature-arc stage. The primary mineral inclusions, such as Na- and K-phlogopites, pargasite-edenite and olivine with subordinate pyroxenes, millerite, and laurite, were trapped within the chromian spinel during the magmatic precipitation of the chromitites. The Abu Dahr chromitites are free of primary hydrous inclusions; on the other hand, Arais and Balamhindit high-Cr chromitites are enriched in Na- and K-phlogopites, respectively, as a result of a difference in the K/Na ratio of the magma responsible for chromitite crystallization at different mantle depths. This difference in the K/Na ratio can possibly be attributed to fractionation of the upward-migrating hydrous fluids/melts by the crystallization of K- or Na-rich minerals. The Balamhindit complex, where the chromitite showed K-phlogopite inclusions within the chromian spinel, was probably derived from a deeper part of the mantle than the other areas, where the chromitite shows inclusions of Na-rich hydrous phases. Both K- and Na-phlogopites were possibly formed from alkali-rich hydrous fluids/melts trapped within the chromian spinels during the chromitite formation at different mantle depths, where the K/Na ratio

  10. Abundance of Zetaproteobacteria within crustal fluids in back-arc hydrothermal fields of the Southern Mariana Trough.

    PubMed

    Kato, Shingo; Yanagawa, Katsunori; Sunamura, Michinari; Takano, Yoshinori; Ishibashi, Jun-ichiro; Kakegawa, Takeshi; Utsumi, Motoo; Yamanaka, Toshiro; Toki, Tomohiro; Noguchi, Takuroh; Kobayashi, Kensei; Moroi, Arimichi; Kimura, Hiroyuki; Kawarabayasi, Yutaka; Marumo, Katsumi; Urabe, Tetsuro; Yamagishi, Akihiko

    2009-12-01

    To extend knowledge of subseafloor microbial communities within the oceanic crust, the abundance, diversity and composition of microbial communities in crustal fluids at back-arc hydrothermal fields of the Southern Mariana Trough (SMT) were investigated using culture-independent molecular techniques based on 16S rRNA gene sequences. Seafloor drilling was carried out at two hydrothermal fields, on- and off-ridge of the back-arc spreading centre of the SMT. 16S rRNA gene clone libraries for bacterial and archaeal communities were constructed from the fluid samples collected from the boreholes. Phylotypes related to Thiomicrospira in the Gammaproteobacteria (putative sulfide-oxidizers) and Mariprofundus in the Zetaproteobacteria (putative iron-oxidizers) were recovered from the fluid samples. A number of unique archaeal phylotypes were also recovered. Fluorescence in situ hybridization (FISH) analysis indicated the presence of active bacterial and archaeal populations in the fluids. The Zetaproteobacteria accounted for up to 32% of the total prokaryotic cell number as shown by FISH analysis using a specific probe designed in this study. Our results lead to the hypothesis that the Zetaproteobacteria play a role in iron oxidation within the oceanic crust.

  11. Abundance of Zetaproteobacteria within crustal fluids in back-arc hydrothermal fields of the Southern Mariana Trough.

    PubMed

    Kato, Shingo; Yanagawa, Katsunori; Sunamura, Michinari; Takano, Yoshinori; Ishibashi, Jun-ichiro; Kakegawa, Takeshi; Utsumi, Motoo; Yamanaka, Toshiro; Toki, Tomohiro; Noguchi, Takuroh; Kobayashi, Kensei; Moroi, Arimichi; Kimura, Hiroyuki; Kawarabayasi, Yutaka; Marumo, Katsumi; Urabe, Tetsuro; Yamagishi, Akihiko

    2009-12-01

    To extend knowledge of subseafloor microbial communities within the oceanic crust, the abundance, diversity and composition of microbial communities in crustal fluids at back-arc hydrothermal fields of the Southern Mariana Trough (SMT) were investigated using culture-independent molecular techniques based on 16S rRNA gene sequences. Seafloor drilling was carried out at two hydrothermal fields, on- and off-ridge of the back-arc spreading centre of the SMT. 16S rRNA gene clone libraries for bacterial and archaeal communities were constructed from the fluid samples collected from the boreholes. Phylotypes related to Thiomicrospira in the Gammaproteobacteria (putative sulfide-oxidizers) and Mariprofundus in the Zetaproteobacteria (putative iron-oxidizers) were recovered from the fluid samples. A number of unique archaeal phylotypes were also recovered. Fluorescence in situ hybridization (FISH) analysis indicated the presence of active bacterial and archaeal populations in the fluids. The Zetaproteobacteria accounted for up to 32% of the total prokaryotic cell number as shown by FISH analysis using a specific probe designed in this study. Our results lead to the hypothesis that the Zetaproteobacteria play a role in iron oxidation within the oceanic crust. PMID:19691504

  12. Fluid-related inclusions in Alpine high-pressure peridotite reveal trace element recycling during subduction-zone dehydration of serpentinized mantle (Cima di Gagnone, Swiss Alps)

    NASA Astrophysics Data System (ADS)

    Scambelluri, Marco; Pettke, Thomas; Cannaò, Enrico

    2015-11-01

    Serpentinites release at sub-arc depths volatiles and several fluid-mobile trace elements found in arc magmas. Constraining element uptake in these rocks and defining the trace element composition of fluids released upon serpentinite dehydration can improve our understanding of mass transfer across subduction zones and to volcanic arcs. The eclogite-facies garnet metaperidotite and chlorite harzburgite bodies embedded in paragneiss of the subduction melange from Cima di Gagnone derive from serpentinized peridotite protoliths and are unique examples of ultramafic rocks that experienced subduction metasomatism and devolatilization. In these rocks, metamorphic olivine and garnet trap polyphase inclusions representing the fluid released during high-pressure breakdown of antigorite and chlorite. Combining major element mapping and laser-ablation ICP-MS bulk inclusion analysis, we characterize the mineral content of polyphase inclusions and quantify the fluid composition. Silicates, Cl-bearing phases, sulphides, carbonates, and oxides document post-entrapment mineral growth in the inclusions starting immediately after fluid entrapment. Compositional data reveal the presence of two different fluid types. The first (type A) records a fluid prominently enriched in fluid-mobile elements, with Cl, Cs, Pb, As, Sb concentrations up to 103 PM (primitive mantle), ∼102 PM Tl, Ba, while Rb, B, Sr, Li, U concentrations are of the order of 101 PM, and alkalis are ∼2 PM. The second fluid (type B) has considerably lower fluid-mobile element enrichments, but its enrichment patterns are comparable to type A fluid. Our data reveal multistage fluid uptake in these peridotite bodies, including selective element enrichment during seafloor alteration, followed by fluid-rock interaction along with subduction metamorphism in the plate interface melange. Here, infiltration of sediment-equilibrated fluid produced significant enrichment of the serpentinites in As, Sb, B, Pb, an enriched trace

  13. Isotopic and fluid-inclusion constraints on the formation of polymetallic vein deposits in the central Argentinian Patagonia

    NASA Astrophysics Data System (ADS)

    Dejonghe, Léon; Darras, Benoît; Hughes, Guillermo; Muchez, Philippe; Scoates, James S.; Weis, Dominique

    2002-03-01

    The lead isotope compositions of galena and the fluid-inclusion systematics of nine barite-bearing polymetallic (Au, Ag, Pb, Zn) deposits of the central Argentinian Patagonia (Chubut and Rio Negro provinces) have been investigated to constrain the compositions and sources of the mineralizing fluids. Most of the deposits occur as veins, with less common wall-rock disseminations and/or stockworks, and are low-sulfidation epithermal deposits hosted in Jurassic volcanic rocks. Fluid-inclusion homogenization temperatures (Th) from quartz and sphalerite from the deposits fall within the range of 100-300 °C, with the highest measured average temperatures for the most eastern deposits (Mina Angela - 298 °C; Cañadón Bagual - 343 °C). The salinities of the hydrothermal fluids at all deposits were low to moderate (≤10.4 equiv. wt% NaCl). Three groups of ore deposits can be defined on the basis of 206Pb/204Pb ratios for galena and these show a general decrease from west to east (from 18.506 to 18.000). The central Argentinian Patagonia deposits have distinctly less radiogenic lead isotope compositions than similar deposits from Peru and Chile, except for the porphyry copper deposits of central and southern Peru. Galena from the Mina Angela deposit is characterized by very low radiogenic lead isotope compositions (18.000<206Pb/204Pb<18.037 and 38.03<208Pb/204Pb<38.09) and reflects interaction with Precambrian basement. The geographic trend in lead isotope compositions of both galena and whole rocks indicates a crustal contribution which increases eastwards, also reflected in the strontium-neodymium isotope systematics of the host lavas. Finally, due to the lack of precise age determinations for the central Patagonian polymetallic deposits, a potential link with Andean porphyry copper systems remains an open question.

  14. Geochronology, fluid inclusions and isotopic characteristics of the Chaganbulagen Pb-Zn-Ag deposit, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Li, Tiegang; Wu, Guang; Liu, Jun; Wang, Guorui; Hu, Yanqing; Zhang, Yunfu; Luo, Dafeng; Mao, Zhihao; Xu, Bei

    2016-09-01

    The large Chaganbulagen Pb-Zn-Ag deposit is located in the Derbugan metallogenic belt of the northern Great Xing'an Range. The vein-style orebodies of the deposit occur in the NWW-trending fault zones. The ore-forming process at the deposit can be divided into three stages: an early quartz-pyrite-arsenopyrite-pyrrhotite-sphalerite-galena-chalcopyrite stage, a middle quartz-carbonate-pyrite-sphalerite-galena-silver-bearing minerals stage, and a late quartz-carbonate-pyrite stage. The sericite sample yielded a 40Ar -39Ar plateau age of 138 ± 1 Ma and an isochron age of 137 ± 3 Ma, and the zircon LA-ICP-MS U-Pb age of monzogranite porphyry was 143 ± 2 Ma, indicating that the ages of mineralization and monzogranite porphyry in the Chaganbulagen deposit should be the Early Cretaceous, and that the mineralization should be slightly later than the intrusion of monzogranite porphyry. There are only liquid inclusions in quartz veins of the Chaganbulagen deposit. Homogenization temperatures, densities, and salinities of the fluid inclusions from the early stage are 261-340 °C, 0.65-0.81 g/cm3, and 0.7-6.3 wt.% NaCl eqv., respectively. Fluid inclusions of the middle stage have homogenization temperatures, densities, and salinities of 209-265 °C, 0.75-0.86 g/cm3, and 0.5-5.7 wt.% NaCl eqv., respectively. For fluid inclusions of the late stage, their homogenization temperatures, densities, and salinities are 173-219 °C, 0.85-0.91 g/cm3, and 0.4-2.7 wt.% NaCl eqv., respectively. The ore-forming fluids of the deposit are generally characterized by moderate temperature and low salinity and density, and belong to an H2O-NaCl ± CO2 ± CH4 system. The δ18Owater values calculated for ore-bearing quartz vary from - 17.9‰ to - 10.8‰, and the δDV-SMOW values from bulk extraction of fluid inclusion waters vary from - 166‰ to - 127‰, suggesting that the ore-forming fluids consist dominantly of meteoric water. The δ34SV-CDT values range from 1.4‰ to 4.1‰. The 206Pb/204

  15. Amplitude of Biot's slow wave scattered by a spherical inclusion in a fluid-saturated poroelastic medium

    NASA Astrophysics Data System (ADS)

    Ciz, Radim; Gurevich, Boris

    2005-03-01

    Spatial heterogeneity of hydrocarbon reservoirs causes significant attenuation and dispersion of seismic waves due to wave-induced flow of the pore fluid between more compliant and less compliant areas. This paper investigates the interaction between a plane elastic wave in a poroelastic medium with a spherical inhomogeneity of another porous material. The behaviour of both the inclusion and the background medium is described by the low-frequency variant of Biot's equations of poroelasticity with the standard boundary conditions at the inclusion surface, and for the inclusion size much smaller than the wavelength of the fast compressional wave. The scattering problem is formulated as a series expansion of displacements expressed in the spherical harmonics. The resulting scattered wavefield consists of the scattered normal compressional and shear waves and Biot's slow wave, which attenuates rapidly with distance from the inclusion and represents the main difference from the elastic case. This study concentrates on the attenuation effects caused by the mode conversion into Biot's slow wave. The solution obtained for Biot's slow wave is well described by the two terms of order n= 0 and n= 2 of the scattering series. The scattering amplitude for the term of order n= 0 is given by a simple expression. The full expression for the term of order n= 2 is very complicated, but can be simplified assuming that the amplitude of the scattered fast (normal) compressional and shear waves are well approximated by the solution of the equivalent elastic problem. This assumption yields a simple approximation for the amplitude of the scattered slow wave, which is accurate for a wide range of material properties and is sufficient for the analysis of the scattering amplitude as a function of frequency. In the low-frequency limit the scattering amplitude of the slow wave scales with ω3/2, and reduces to the asymptotic long-wavelength solution of Berryman (1985), which is valid for

  16. Chemistry of fluid inclusions in halite from the Salina group of the Michigan basin: Implications for Late Silurian seawater and the origin of sedimentary brines

    SciTech Connect

    Das, N.; Horita, J.; Holland, H.D. )

    1990-02-01

    Fluid was extracted from 18 fluid inclusions in halite of the Late Silurian Salina Group exposed in the Crystal Mine on the outskirts of Detroit, Michigan. Compared with modern seawater evaporated to the same degree, the inclusion fluids are severely depleted in SO{sub 4}{sup {minus}2}, somewhat depleted in Na{sup +} and Mg{sup +2}, and greatly enriched in Ca{sup +2}. The composition of the inclusion fluids can be derived from Silurian seawater with a composition close to that of modern seawater, if it is assumed that the composition of the Silurian seawater was modified by dolomitizing CaCO{sub 3}-rich sediments and by albitizing silicate minerals during its evolution into evaporite brines. Since the evolution of the brines involved a number of chemical reactions, it is impossible to recover the initial concentration of all of the major ions in the parent Silurian seawater from the composition of the inclusion fluids alone. It is likely, however, that the m{sub K+}/m{sub Br-} ratio and the functions in Late Silurian seawater had values close to those of modern seawater. Measurements of the isotopic composition of sulfur and of Sr in anhydrite within and associated with the halite host of the fluid inclusions are consistent with previous measurements of {delta}{sup 34}S in Silurian marine anhydrites and with the {sup 87}Sr/{sup 86}Sr ratios of Late Silurian marine carbonates.

  17. Rock chemistry and fluid inclusion studies as exploration tools for ore deposits in the Sila batholith, southern Italy

    USGS Publications Warehouse

    de Vivo, B.; Ayuso, R.A.; Belkin, H.E.; Lima, A.; Messina, A.; Viscardi, A.

    1991-01-01

    The Sila batholith is the focus of an extensive petrogenetic research program, which includes an assessment of its potential to host granite-related ore deposits. Univariate and multivariate statistical techniques were applied to major- and minor-element rock geochemical data. The analysis indicates that the highest potential for mineralization occurs in corundum-normative, peraluminous, unfoliated, relatively late-stage plutons. The plutons are enriched in Rb, Nb, Ta and U, but depleted in Fe, Mg and Sr. The K/Rb, Ba/Rb, Rb/Sr and Rb3/Ba??Sr??K indices and high R-factor scores of Si-K-Rb are typical of mineralized granitic rocks. A reconnaissance fluid inclusion study indicates that the sub-solidus rock was infiltrated by solutions of widely different temperatures (50-416??C) and variable salinities (0 to ???26 wt.% NaCl equivalent). The higher-temperature solutions probably represent granite or magmatic-related Hercynian fluids, whereas the lower-temperature fluids may be either Hercynian or Alpine in age. Fluids with characteristics typical of mineralized "porphyry" systems have not been recognized. ?? 1991.

  18. Fluid inclusion and stable isotope studies of the Mesloula Pb-Zn-Ba ore deposit, NE Algeria: Characteristics and origin of the mineralizing fluids

    NASA Astrophysics Data System (ADS)

    Laouar, Rabah; Salmi-Laouar, Sihem; Sami, Lounis; Boyce, Adrian J.; Kolli, Omar; Boutaleb, Abdelhak; Fallick, Anthony E.

    2016-09-01

    In the Saharan Atlas (NE Algeria), the Triassic evaporitic formation was brought to the surface through the thick Cretaceous and Tertiary sedimentary cover as diapirs due to the effect of Atlasic tectonic events. The diapir piercing began in the Jurassic and has continued through present day. Many outcrops of several square kilometres are distributed in a large area (approximately 80 km wide) that extends northeasterly over 300 km towards Tunisia. The diapiric evaporitic formation is often accompanied by the emplacement of Pb-Zn-Ba-F mineralization. The Mesloula massif is an example of these deposits. Fluid inclusion and sulphur, carbon and oxygen isotope studies were carried out on Pb-Zn-Ba mineralization and associated gangue carbonates. Gypsum of the Triassic formation was also analysed for its sulphur isotope composition to show the role of evaporates in the generation of this typical peridiapiric deposit. Gypsum from the Triassic formation showed a narrow range of δ34SVCDT values, ranging from +14.6 to +15.5‰ (n = 8). This range is comparable to that of Triassic seawater sulphates. Sulphide minerals yielded δ34SVCDT values between 0 and + 11.7‰ (n = 15), indicating that sulphide sulphur was likely derived from Triassic sulphates through thermochemical sulphate reduction (TSR) because fluid inclusion microthermometric measurements yielded a mean temperature of 150 °C. Residual sulphate in such a system would have been enriched in 34S; this is reflected in the barite δ34SVCDT values, which range from +21.1 to +33.5‰ (n = 5). The δ13CVPDB values of calcite minerals, ranging from +2.1 to +6.3‰ (n = 4), indicate an inorganic carbon origin, likely from the host carbonate rocks. δ18OVSMOW values were between +21.9 and + 24.9‰, indicating that the most likely source of mineralizing fluids was formation water.

  19. ORIGIN OF THERMAL FLUIDS AT LASSEN VOLCANIC NATIONAL PARK: EVIDENCE FROM NOBLE AND REACTIVE GAS ABUNDANCES.

    USGS Publications Warehouse

    Truesdell, Alfred H.; Mazor, Emanuel; Nehring, Nancy L.

    1983-01-01

    Thermal fluid discharges at Lassen are dominated by high-altitude fumaroles and acid-sulfate hot springs in the Park, and lower altitude, neutral, high-chloride hot springs in Mill Valley 7-10 km to the south. The interrelations of these fluids have been studied by noble and reactive gas analyses. Atmospheric noble gas (ANG) contents of superheated fumaroles are similar to those of air-saturated recharge water (ASW) at 5 degree C and 2500-m elevation. Low-elevation, high-chloride, hot-spring waters are highly depleted in ANG, relative to the ASW. The surface temperatures and gas chemistry of the fumaroles and hot springs suggest that steam originating from partial to near-complete vaporization of liquid from a boiling, high-chloride, hot water aquifer is decompressed adiabatically, and more or less mixed with shallow groundwater to form superheated and drowned fumaroles within the Park. Refs.

  20. Are the 3,800-Myr-old Isua objects microfossils, limonite-stained fluid inclusions, or neither?

    USGS Publications Warehouse

    Roedder, E.

    1981-01-01

    Bridgwater et al.1 issued a 'cautionary note' concerning several reports published by Pflug and co-workers2-5 describing objects called yeast-like microfossils (Isuasphaera isua Pflug) from a metamorphosed quartzite of the 3,800-Myr-old Isua supracrustal belt of south-west Greenland; Bridgwater et al. believe that the objects described by Pflug et al. 2-5 are 'indistinguishable from limonite-stained fluid inclusions' and hence are non-biogenic. I show here that the objects are neither limonite-stained fluid inclusions nor microfossils, but are limonite-stained cavities from the otherwise complete dissolution by weathering of ferruginous dolomite grains in these rocks. Several supporting arguments presented by both sides are believed to be invalid, and others are ambiguous. In view of the extensive research on the earliest life forms, and then significance to evolution, to early geochemical cycles and to the origin of the atmosphere and some ore deposits, the exact nature of the Isua objects, and particularly the validity of the evidence either for or against a biological origin, are of considerable importance. A careful evaluation of the evidence from Isua is particularly pertinent, as bona fide Precambrian fossils are also found in chemically similar (but much younger) silica-rich environments. ?? 1981 Nature Publishing Group.

  1. Are the 3,800-Myr-old Isua objects microfossils, limonite-stained fluid inclusions, or neither?

    NASA Astrophysics Data System (ADS)

    Roedder, Edwin

    1981-10-01

    Bridgwater et al.1 issued a `cautionary note' concerning several reports published by Pflug and co-workers2-5 describing objects called yeast-like microfossils (Isuasphaera isua Pflug) from a metamorphosed quartzite of the 3,800-Myr-old Isua supracrustal belt of south-west Greenland; Bridgwater et al. believe that the objects described by Pflug et al.2-5 are `indistinguishable from limonite-stained fluid inclusions' and hence are non-biogenic. I show here that the objects are neither limonite-stained fluid inclusions nor microfossils, but are limonite-stained cavities from the otherwise complete dissolution by weathering of ferruginous dolomite grains in these rocks. Several supporting arguments presented by both sides are believed to be invalid, and others are ambiguous. In view of the extensive research on the earliest life forms, and then significance to evolution, to early geochemical cycles and to the origin of the atmosphere and some ore deposits, the exact nature of the Isua objects, and particularly the validity of the evidence either for or against a biological origin, are of considerable importance. A careful evaluation of the evidence from Isua is particularly pertinent, as bona fide Precambrian fossils are also found in chemically similar (but much younger) silica-rich environments.

  2. Postmetamorphic unroofing history deduced from petrology, fluid inclusions, thermochronometry, and thermal modeling: An example from southwestern New England

    SciTech Connect

    Hames, W.E.; Tracy, R.J.; Bodnar, R.J. )

    1989-08-01

    Nonlinear unroofing rates from {approximately}10 to <1 mm/yr following high-pressure Acadian (Devonian) metamorphism have been documented in southwestern New England by using combined petrologic, fluid inclusion, thermochronometric, and thermal modeling techniques. Thermobarometry of pelitic schists from the Rowe-Hawley belt of western Connecticut indicates peak Acadian pressure-temperature conditions of 8.2 kbar and 575C. Densities of CO{sub 2}- and H{sub 2}O-rich fluid inclusions require nearly isothermal decompression followed by more isobaric cooling from these conditions. Comparison of this observed path to those generated by thermal models suggests that decompression was characterized by initial rapid upward en bloc velocity ({approximately}1 cm/yr) of brief duration, followed by much slower unroofing rates ({le}0.3 mm/yr). Published geochronologic ages in this region constrain the rapid uplift to the Middle Devonian, and uplift slowed dramatically by the end of the Devonian. This differential uplift has major implications for interpretation of Devonian igneous activity and sedimentation in southwestern New England.

  3. D/H ratios in speleothem fluid inclusions: A guide to variations in the isotopic composition of meteoric precipitation?

    USGS Publications Warehouse

    Harmon, R.S.; Schwarcz, H.P.; O'Neil, J.R.

    1979-01-01

    D/H ratios of fluid inclusion waters extracted from 230Th/234U-dated speleothems that were originally deposited under conditions of isotopic equilibrium should provide a direct estimate of the hydrogen isotopic composition of ancient meteoric waters. We present here D/H ratios for 47 fluid inclusion samples from thirteen speleothems deposited over the past 250,000 years at cave sites in Iowa, West Virginia, Kentucky and Missouri. At each site glacial-age waters are depleted in deuterium relative to those of interglacial age. The average interglacial/glacial shift in the hydrogen isotopic composition of meteoric precipitation over ice-free areas of east-central North America is estimated to be -12???. This shift is consistent with the present climatic models and can be explained in terms of the prevailing pattern of atmospheric circulation and an increased ocean-continent temperature gradient during glacial times which more than compensated for the increase in deuterium content of the world ocean. ?? 1979.

  4. Influence of isotopic re-equilibration on speleothem and fluid inclusion isotope ratios after primary calcite precipitation

    NASA Astrophysics Data System (ADS)

    Kluge, Tobias; Haderlein, Astrid; Weißbach, Therese

    2016-04-01

    Oxygen isotope ratios in speleothems (notably stalagmites) have been used since decades to successfully infer paleotemperatures and deduce paleo-environmental information. In addition, recent technical developments allow to increasingly use fluid inclusions as an archive for drip-water and together with the surrounding calcite as paleothermometer. A basic requirement for isotope data interpretation is the complete knowledge of the fractionation between calcite and fluid. Most laboratory and in-situ cave experiments focus on calcite growth and the isotope fractionation between calcite and feed solution. Potential isotope exchange and re-equilibration processes after the initial deposition have mostly been neglected. However, experiments of Oelkers et al. (2015) showed that the isotope exchange between minerals and fluid can proceed rapidly (within days), even at chemical equilibrium. In hydrous Mg carbonates a similar process of continuous isotope exchange between carbonate and fluid was observed after the carbonate precipitation was completed (Mavromatis et al., 2015). These observations suggest that the isotope ratios of speleothem calcite may be affected by this continuous exchange, likely driving the isotope composition continuously towards equilibrium at the respective cave conditions. In addition, fluid inclusions are suspected to be sensitive to an isotope exchange with the surrounding carbonate highlighting the need to precisely understand and quantify this effect. We assessed the oxygen isotope exchange between calcite and solution at chemical equilibrium conditions with theoretical estimates and laboratory experiments over an intermediate time scale (hours-weeks). A large isotope gradient (~20 ‰)) between solution and calcite was prepared in the experiment to investigate the dynamics of this re-equilibration process. We used a theoretical model based on a Rayleigh fractionation approach and the direct comparison with the experiment to determine

  5. Application of Scanning-Imaging X-Ray Microscopy to Fluid Inclusion Candidates in Carbonates of Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Tsuchiyama, Akira; Nakano, Tsukasa; Miyake, Akira; Akihisa, Takeuchi; Uesugi, Kentaro; Suzuki, Yoshio; Kitayama, Akira; Matsuno, Junya; Zolensky, Michael E.

    2016-01-01

    In order to search for such fluid inclusions in carbonaceous chondrites, a nondestructive technique using x-ray micro-absorption tomography combined with FIB sampling was developed and applied to a carbonaceous chondrite. They found fluid inclusion candidates in calcite grains, which were formed by aqueous alteration. However, they could not determine whether they are really aqueous fluids or merely voids. Phase and absorption contrast images can be simultaneously obtained in 3D by using scanning-imaging x-ray microscopy (SIXM). In refractive index, n=1-sigma+i(beta), in the real part, 1-sigma is the refractive index with decrement, sigma, which is nearly proportional to the density, and the imaginary part, beta, is the extinction coefficient, which is related to the liner attenuation coefficient, mu. Many phases, including water and organic materials as well as minerals, can be identified by SIXM, and this technique has potential availability for Hayabusa-2 sample analysis too. In this study, we examined quantitative performance of d and m values and the spatial resolution in SIXM by using standard materials, and applied this technique to carbonaceous chondrite samples. We used POM ([CH2O]n), silicon, quartz, forsterite, corundum, magnetite and nickel as standard materials for examining the sigma and mu values. A fluid inclusion in terrestrial quartz and bi-valve shell (Atrina vexillum), which are composed of calcite and organic layers with different thickness, were also used for examining the spatial resolution. The Ivuna (CI) and Sutter's Mill (CM) meteorites were used as carbonaceous chondrite samples. Rod- or cube-shaped samples 20-30 micron in size were extracted by using FIB from cross-sectional surfaces of the standard materials or polished thin sections of the chondrites, which was previously observed with SEM. Then, the sample was attached to a thin W-needle and imaged by SIXM system at beamline BL47XU, SPring-8, Japan. The slice thickness was 109.3 nm

  6. Search for Fluid Inclusions in a Carbonaceous Chondrite Using a New X-Ray Micro-Tomography Technique Combined with FIB Sampling

    NASA Technical Reports Server (NTRS)

    Tsuchiyama, A.; Miyake, A.; Zolensky, M. E.; Uesugi, K.; Nakano, T.; Takeuchi, A.; Suzuki, Y.; Yoshida, K.

    2014-01-01

    Early solar system aqueous fluids are preserved in some H chondrites as aqueous fluid inclusions in halite (e.g., [1]). Although potential fluid inclusions are also expected in carbonaceous chondrites [2], they have not been surely confirmed. In order to search for these fluid inclusions, we have developped a new X-ray micro-tomography technique combined with FIB sampling and applied this techniqu to a carbanaceous chondrite. Experimental: A polished thin section of Sutter's Mill meteorite (CM) was observed with an optical microscope and FE-SEM (JEOL 7001F) for chosing mineral grains of carbonates (mainly calcite) and sulfides (FeS and ZnS) 20-50 microns in typical size, which may have aqueous fluid inclusions. Then, a "house" similar to a cube with a roof (20-30 microns in size) is sampled from the mineral grain by using FIB (FEI Quanta 200 3DS). Then, the house was atached to a thin W-needle by FIB and imaged by a SR-based imaging microtomography system with a Fresnel zone plate at beamline BL47XU, SPring-8, Japan. One sample was imaged at two X-ray energies, 7 and 8 keV, to identify mineral phases (dual-enegy microtomography: [3]). The size of voxel (pixel in 3D) was 50-80 nm, which gave the effective spatial resolution of approx. 200 nm. A terrestrial quartz sample with an aqueous fluid inclusion with a bubble was also examined as a test sample by the same method. Results and discussion: A fluid inclusion of 5-8 microns in quartz was clearly identified in a CT image. A bubble of approx. 4 microns was also identified as refraction contrast although the X-ray absorption difference between fluid and bubble is small. Volumes of the fluid and bubble were obtained from the 3D CT images. Fourteen grains of calcite, two grains of iron sulfide and one grain of (Zn,Fe)S were examined. Ten calcite, one iron sulfide and one (Zn,Fe)S grains have inclusions >1 micron in size (the maximum: approx. 5 microns). The shapes are spherical or irregular. Tiny inclusions (<1 micron

  7. In situ quantitative analysis of individual H2O-CO2 fluid inclusions by laser Raman spectroscopy

    USGS Publications Warehouse

    Azbej, T.; Severs, M.J.; Rusk, B.G.; Bodnar, R.J.

    2007-01-01

    Raman spectral parameters for the Raman ??1 (1285??cm- 1) and 2??2 (1388??cm- 1) bands for CO2 and for the O-H stretching vibration band of H2O (3600??cm- 1) were determined in H2O-CO2 fluid inclusions. Synthetic fluid inclusions containing 2.5 to 50??mol% CO2 were analyzed at temperatures equal to or greater than the homogenization temperature. The results were used to develop an empirical relationship between composition and Raman spectral parameters. The linear peak intensity ratio (IR = ICO2/(ICO2 + IH2O)) is related to the CO2 concentration in the inclusion according to the relation:Mole % C O2 = e- 3.959 IR2 + 8.0734 IRwhere ICO2 is the intensity of the 1388 cm- 1 peak and IH2O is the intensity of the 3600 cm- 1 peak. The relationship between linear peak intensity and composition was established at 350????C for compositions ranging from 2.5 to 50??mol% CO2. The CO2-H2O linear peak intensity ratio (IR) varies with temperature and the relationship between composition and IR is strictly valid only if the inclusions are analyzed at 350????C. The peak area ratio is defined as AR = ACO2/(ACO2 + AH2O), where ACO2 is the integrated area under the 1388??cm- 1 peak and AH2O is the integrated area under the 3600??cm- 1 peak. The relationship between peak area ratio (AR) and the CO2 concentration in the inclusions is given as:Mole % C O2 = 312.5 AR. The equation relating peak area ratio and composition is valid up to 25??mol% CO2 and from 300 to 450????C. The relationship between linear peak intensity ratio and composition should be used for inclusions containing ??? 50??mol% CO2 and which can be analyzed at 350????C. The relationship between composition and peak area ratios should be used when analyzing inclusions at temperatures less than or greater than 350????C (300-450) but can only be used for compositions ??? 25??mol% CO2. Note that this latter relationship has a somewhat larger standard deviation compared to the intensity ratio relationship. Calibration

  8. Fluid inclusion characteristics and molybdenite Re-Os geochronology of the Qulong porphyry copper-molybdenum deposit, Tibet

    NASA Astrophysics Data System (ADS)

    Li, Yang; Selby, David; Feely, Martin; Costanzo, Alessandra; Li, Xian-Hua

    2016-04-01

    The Qulong porphyry copper and molybdenum deposit is located at the southwest margin of the Lhasa Terrane and in the eastern region of the Gangdese magmatic belt. It represents China's largest porphyry copper system, with ˜2200 million tonnes of ore comprising 0.5 % Cu and 0.03 % Mo. The mineralization is associated with Miocene granodiorite, monzogranite and quartz-diorite units, which intruded into Jurassic volcanic units in a post-collisional (Indian-Asian) tectonic setting. Field observations and core logging demonstrate the alteration and mineralization at Qulong are akin to typical porphyry copper systems in subduction settings, which comprise similar magmatic-hydrothermal, potassic, propylitic and phyllic alteration assemblages. Molybdenite Re-Os geochronology confirms the relative timeframe defined by field observations and core logging and indicates that the bulk copper and molybdenum at Qulong were deposited within 350,000 years: between 16.10 ± 0.06 [0.08] (without and with decay constant uncertainty) and 15.88 ± 0.06 [0.08] Ma. This duration for mineralization is in direct contrast to a long-lived intrusive episode associated with mineralization based on previous zircon U-Pb data. Our fluid inclusion study indicates that the ore-forming fluid was oxidized and contained Na, K, Ca, Fe, Cu, Mo, Cl and S. The magmatic-hydrothermal transition occurred at ˜425 °C under lithostatic pressure, while potassic, propylitic and phyllic alteration occurred at hydrostatic pressure with temperature progressively decreasing from 425 to 280 °C. The fluid inclusion data presented here suggests that there has been ˜2.3 km of erosion at Qulong after its formation, and this erosion may be related to regional uplift of the Lhasa Terrane.

  9. In-situ pressure - temperature condition of tectonic melange : constraints from fluid inclusion analysis of syn-melange veins-

    NASA Astrophysics Data System (ADS)

    Hashimoto, Y.; Enjoji, M.; Sakaguchi, A.; Kimura, G.

    2001-12-01

    One of the most reliable settings for the tectonic melange with composite planar fabric is along the decollement in the subduction zone (e.g. Cowan, 1985; Moore and Byrne, 1987; Kimura and Mukai, 1991). The decollement is developed from aseismic shallow part to seismogenic zone of several to tens of kilometer in depth. The decollement-related-melange, now exposed on land, might therefore record the deformation process along the aseismic to seismogenic decollement. Trapped pressure and temperature of fluid inclusion is estimated from "syn-melange" veins developed around the necks of boudin of sandstone blocks in the melange of the Shimanto Belt, SW Japan. The melange was decollement-related tectonic melange. Fluid inclusion analysis from "syn-melange" veins might be only tool to reveal the P-T condition during melange formation. The result of P-T estimation ranges from about 150 (}25)° Cto 220 (}31)° C for temperature and from 81 (+15) MPa to 235 (_}18) MPa for pressure. Geothermal gradient estimated from the result is between about 10.0 (+0.2/-1.5)° C/km (lithostatic) and 4.2 (+0.1/-0.9)° C/km (hydrostatic) if the fluid pressure ratio to lithostatic pressure is constant in each datum. The estimated lithostatic thermal gradient is much closer to that calculated from the oldness of the subducting oceanic plate. P-T range suggests that melange was formed enough within the seismogenic zone hypothesized by thermal model although the deformation mechanisms of melange, dominant diffusive mass transfer with minor brittle breakage, do not show the seismic deformation. One possible explanation for this discrepancy is that the melange was formed during the interseismic period. Alternative explanation is that melange formation was accomplished before subducting into the seismogenic zone but around the seismic front. Lithification front hypothesis for the seismic front suggests such frontal setting for the melange.

  10. Methane-bearing fluid inclusions as evidence of the collisional nature of high-alumina granites, northern Sikhote-Alin, Russian Far East

    SciTech Connect

    Berdnikov, N.V.; Karsakov, L.P.

    1999-07-01

    The Khungariisk high-alumina S-type granites (northern Sikhote-Alin fold system, Russian Far East) have been formed as a result of anatectic melting during collision of the Anyuy sialic block with the continental margin in the Early Cretaceous. Methane-rich fluid inclusions are characteristic of these granites. The CH{sub 4}-H{sub 2}O fluid composition is explained by the release of water and methane from the sedimentary units residing on the oceanic plate, as it was subducted beneath sialic block. This fluid seeped into the heated and deformed metamorphic rocks of the overlying block and initiated partial fusion of the granites. A comparison of the new data with the results of fluid-inclusion studies of high-alumina collisional granites from the Pamir Mountains and Japan reveals similarities. Thus, methane-bearing fluid is probably one of the general features of this granite type, reflecting its anatectic origin.

  11. Phase equilibrium modeling, fluid inclusions and origin of charnockites in the Datian region of the northeastern Cathaysia Block, South China

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Qiang; Li, Zi-Long; Yu, Sheng-Qiang

    2016-08-01

    Charnockites in the Datian region of the northeastern Cathaysia Block, South China have an assemblage of garnet, clinopyroxene, orthopyroxene, plagioclase, anti-perthite, K-feldspar, biotite, quartz and ilmenite. Phase equilibrium modeling indicates that the Datian charnockite was formed at T = 845-855 °C and P = 8.2-8.4 kbar with corresponding water activity lower than 0.50. Fluid inclusions in the Datian charnockite are dominated by N2 and CO2 with minor CH4. The fluids homogenized to liquid at -153.0 to -138.8 °C and 18.3-21.6 °C, respectively, showing a low-density nature. The low-density fluids could be attributed to selective leakage of water due to the affinity of water to melt and decompression-dominated retrograde process. Combined with previous studies, a two-stage formation model is proposed to interpret the petrogenesis of the Datian charnockite, viz emplaced at the Paleoproterozoic and underwent the granulite-facies metamorphism during the Phanerozoic tectonic event.

  12. Origin of the Rubian carbonate-hosted magnesite deposit, Galicia, NW Spain: mineralogical, REE, fluid inclusion and isotope evidence

    NASA Astrophysics Data System (ADS)

    Kilias, Stephanos P.; Pozo, Manuel; Bustillo, Manuel; Stamatakis, Michael G.; Calvo, José P.

    2006-10-01

    The Rubian magnesite deposit (West Asturian—Leonese Zone, Iberian Variscan belt) is hosted by a 100-m-thick folded and metamorphosed Lower Cambrian carbonate/siliciclastic metasedimentary sequence—the Cándana Limestone Formation. It comprises upper (20-m thickness) and lower (17-m thickness) lens-shaped ore bodies separated by 55 m of slates and micaceous schists. The main (lower) magnesite ore body comprises a package of magnesite beds with dolomite-rich intercalations, sandwiched between slates and micaceous schists. In the upper ore body, the magnesite beds are thinner (centimetre scale mainly) and occur between slate beds. Mafic dolerite dykes intrude the mineralisation. The mineralisation passes eastwards into sequence of bedded dolostone (Buxan) and laminated to banded calcitic marble (Mao). These show significant Variscan extensional shearing or fold-related deformation, whereas neither Rubian dolomite nor magnesite show evidence of tectonic disturbance. This suggests that the dolomitisation and magnesite formation postdate the main Variscan deformation. In addition, the morphology of magnesite crystals and primary fluid inclusions indicate that magnesite is a neoformed hydrothermal mineral. Magnesite contains irregularly distributed dolomite inclusions (<50 μm) and these are interpreted as relics of a metasomatically replaced dolostone precursor. The total rare earth element (REE) contents of magnesite are very similar to those of Buxan dolostone but are depleted in light rare earth elements (LREE); heavy rare earth element concentrations are comparable. However, magnesite REE chondrite normalised profiles lack any characteristic anomaly indicative of marine environment. Compared with Mao calcite, magnesite is distinct in terms of both REE concentrations and patterns. Fluid inclusion studies show that the mineralising fluids were MgCl2-NaCl-CaCl2-H2O aqueous brines exhibiting highly variable salinities (3.3 to 29.5 wt.% salts). This may be the result

  13. Analysis of hopanes and steranes in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS).

    PubMed

    Siljeström, S; Lausmaa, J; Sjövall, P; Broman, C; Thiel, V; Hode, T

    2010-01-01

    Steranes and hopanes are organic biomarkers used as indicators for the first appearance of eukaryotes and cyanobacteria on Earth. Oil-bearing fluid inclusions may provide a contamination-free source of Precambrian biomarkers, as the oil has been secluded from the environment since the formation of the inclusion. However, analysis of biomarkers in single oil-bearing fluid inclusions, which is often necessary due to the presence of different generations of inclusions, has not been possible due to the small size of most inclusions. Here, we have used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to monitor in real time the opening of individual inclusions trapped in hydrothermal veins of fluorite and calcite and containing oil from Ordovician source rocks. Opening of the inclusions was performed by using a focused C(60)(+) ion beam and the in situ content was precisely analysed for C(27)-C(29) steranes and C(29)-C(32) hopanes using Bi(3)(+) as primary ions. The capacity to unambiguously detect these biomarkers in the picoliter amount of crude oil from a single, normal-sized (15-30 mum in diameter) inclusion makes the approach promising in the search of organic biomarkers for life's early evolution on Earth.

  14. Analysis of hopanes and steranes in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS).

    PubMed

    Siljeström, S; Lausmaa, J; Sjövall, P; Broman, C; Thiel, V; Hode, T

    2010-01-01

    Steranes and hopanes are organic biomarkers used as indicators for the first appearance of eukaryotes and cyanobacteria on Earth. Oil-bearing fluid inclusions may provide a contamination-free source of Precambrian biomarkers, as the oil has been secluded from the environment since the formation of the inclusion. However, analysis of biomarkers in single oil-bearing fluid inclusions, which is often necessary due to the presence of different generations of inclusions, has not been possible due to the small size of most inclusions. Here, we have used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to monitor in real time the opening of individual inclusions trapped in hydrothermal veins of fluorite and calcite and containing oil from Ordovician source rocks. Opening of the inclusions was performed by using a focused C(60)(+) ion beam and the in situ content was precisely analysed for C(27)-C(29) steranes and C(29)-C(32) hopanes using Bi(3)(+) as primary ions. The capacity to unambiguously detect these biomarkers in the picoliter amount of crude oil from a single, normal-sized (15-30 mum in diameter) inclusion makes the approach promising in the search of organic biomarkers for life's early evolution on Earth. PMID:19912374

  15. Fluid inclusion and cathodoluminescence studies on fluorite from the Kerio valley, Kenya

    NASA Astrophysics Data System (ADS)

    Ogola, J. S.; Behr, H. J.; van den Kerkhof, A. M.

    1994-04-01

    The Kerio valley lies between the Elgeyo escarpment and the Tugen hills which mark the western margin of the Kenya rift valley. The main fluorite deposits are located in the southern part of the valley at Kimwarer, Choff and Kamnaon. Three types of inclusion fillings were identified: Liquid+Vapour, Liquid+Daughter Minerals and Liquid. The L+V type is dominant. Inclusions occur as clusters, trails along the crystal growth zones and as isolated ones. Low salinities, apparently lower than the 5% wt. NaCl equivalent, were established. Homogenization temperatures suggest that fluorite mineralization took place at different stages and at temperatures between 120 and 180 °C. Isolated readings above 180°C may be referring to the original inclusions in limestone. These measurements and the absence of CO 2 in the inclusions, as well as the occurrence of vugs and crustifications with fluorite, suggest that mineralization took place at relatively shallow depths. Emission spectrum lines representing Eu 2+, Dy 3+, Tb 3+ and Sm 3+ in fluorite were identified. Sm 3+ was detected only in the pinkish luminescence of veined fluorite, whereas the pinkish zone in banded fluorite contains Tb 3+. Eu 2+ which gives the strongest emission lines in the blue part of the visible spectrum, apparently is responsible for the strong blue cathodoluminescence (CL) in fluorite. The dominance of Eu 2+ peaks further points to the fact that fluorite mineralization in the Kerio valley took place in an environment that was enriched in Lanthanide Rare Earth Elements (LREE). The presence of rare earths and radioactive elements in fluorite points towards their enrichment in the environment of fluorite mineralization. A juvenile origin of mineral forming solutions is proposed. Two generations of fluorite were established: allotriomorphic fluorite, forming the matrix, and the idiomorphic variety, occurring either in barite or in druzes in early fluorite. Barite in turn forms idiomorphic crystals in

  16. A new purge-and-trap headspace technique to analyse volatile organohalogens from fluid inclusions of rocks and minerals

    NASA Astrophysics Data System (ADS)

    Mulder, Ines; Huber, Stefan; Schöler, Heinfried

    2010-05-01

    Recently, advances were made in the detection of low boiling point volatile organohalogens (VOCs) at trace gas concentrations of air samples employing sophisticated and complex experimental setups (Sive et al. 2005, Miller et al. 2008) while conventional fluid inclusion gas analysis via GC/MS (gas chromatography coupled with mass spectrometry) do not include halogenated VOCs in their analytical routine (e.g. Samson et al. 2003). At the same time Svensen et al. (2009) have just confirmed the release of chlorinated and brominated VOC from halites after heat treatment using GC/MS into which they injected compounds previously trapped on adsorption tubes. Already in 1998, Harnish and Eisenhauer reported the presence of CF4 and SF6 released from natural fluorite and granite samples after milling but appear to have received little resonance in the scientific community. In this work we present the development of a new method for the analysis of halogenated VOCs from fluid inclusions. The mineral or rock sample is milled in an air-tight tempered steel container that fits into a regular planetary mill. Starting at a particle size of around 2-3 mm a final mean particle fineness of 1000 to 750 nm for quartz and fluorites, respectively, is achieved. The grinding container is equipped with two septa that can be pierced by the two needles through which the sample is connected to the GC/MS system and through which the gases are purged similar to a standard purge-and-trap system. The gases are trapped at liquid nitrogen temperatures before entering directly onto the column of the GC/MS system. Compounds that were released during grinding are separated and detected by an ion trap mass spectrometer. To prevent contamination with fine particles a 0.5 µm sintered steel filter element is interconnected after the sample needle. Optimizations and calibrations were conducted using diluted pure gases. First results show that this modified GC/MS purge-and-trap method appears to be an

  17. Fluid-Melt-Crust Interactions Beneath The Andean Arc: Textures, Crystal Zoning and CO2- Inclusions In Gabbroic Xenoliths From San Pedro Volcano (SVZ)

    NASA Astrophysics Data System (ADS)

    Ginibre, C.; Dungan, M. A.

    2006-12-01

    Crustal sections beneath active continental arcs are `percolation columns' in which the crust is continuously under modification by pluton emplacement, circulating fluids, and interactions with ascending magmas. Amphibole- and phlogopite-bearing gabbroic xenoliths from a Holocene dacite of V. San Pedro have been interpreted as formed by the reaction of a hydrous silicic melt with a partly solidified cumulate pile (Costa et al. 2001). Optical microscopy and back-scattered electron images reveal complex textures including partial melt zones, numerous arrays of secondary fluid inclusions, and, in some samples, melt inclusions, mainly in olivine. Three main stages are identified. (1) Metasomatism of original gabbroic cumulates leads to the formation of poikilitic hornblende, micas, orthopyroxene and sodic plagioclase by reaction of olivine, plagioclase and possibly clinopyroxene with hydrous melt. (2) Fluid infiltration along cracks, now preserved as fluid-bearing healed microfractures affects olivine, most orthopyroxene, clinopyroxene, plagioclase and first stage amphibole. (3) Destabilization and melting, mainly of the hydrous minerals, occur during the remobilization in the host lava, associated with new mineral growth. Amphibole, orthopyroxene, olivine, and sodic feldspar produced in stage (3) resemble those from stage (1) but lack fluid inclusions. Fracture and melt migration at this stage is observed as veinlets cross-cutting various minerals. Inclusions analysed by Raman spectroscopy and microthermometry contain CO2 fluids with a small amount of N2. Their low density, below the critical density, implies equilibration at pressures lower than 2 kbar. Variations between inclusion arrays suggests several generations of fluids under variable conditions. LA ICPMS data of inclusions in olivine show low trace element contents in early, dense inclusions and more trace elements (Th, Sr, Pb) in late, very low-density fluids suggesting possibly aqueous fluid (although not

  18. Fluid inclusion and stable isotope (O, H, C, and S) constraints on the genesis of the Serrinha gold deposit, Gurupi Belt, northern Brazil

    NASA Astrophysics Data System (ADS)

    Klein, Evandro L.; Harris, Chris; Renac, Christophe; Giret, André; Moura, Candido A. V.; Fuzikawa, Kazuo

    2006-05-01

    The Serrinha gold deposit of the Gurupi Belt, northern Brazil, belongs to the class of orogenic gold deposits. The deposit is hosted in highly strained graphitic schist belonging to a Paleoproterozoic (˜2,160 Ma) metavolcano-sedimentary sequence. The ore-zones are up to 11 m thick, parallel to the regional NW-SE schistosity, and characterized by quartz-carbonate-sulfide veinlets and minor disseminations. Textural and structural data indicate that mineralization was syn- to late-tectonic and postmetamorphic. Fluid inclusion studies identified early CO2 (CH4-N2) and CO2 (CH4-N2)-H2O-NaCl inclusions that show highly variable phase ratios, CO2 homogenization, and total homogenization temperatures both to liquid and vapor, interpreted as the product of fluid immiscibility under fluctuating pressure conditions, more or less associated with postentrapment modifications. The ore-bearing fluid typically has 18-33mol% of CO2, up to 4mol% of N2, and less than 2mol% of CH4 and displays moderate to high densities with salinity around 4.5wt% NaCl equiv. Mineralization occurred around 310 to 335°C and 1.3 to 3.0 kbar, based on fluid inclusion homogenization temperatures and oxygen isotope thermometry with estimated oxygen fugacity indicating relatively reduced conditions. Stable isotope data on quartz, carbonate, and fluid inclusions suggest that veins formed from fluids with δ18OH2O and δDH2O (310-335°C) values of +6.2 to +8.4‰ and -19 to -80‰, respectively, which might be metamorphic and/or magmatic and/or mantle-derived. The carbon isotope composition (δ13C) varies from -14.2 to -15.7‰ in carbonates; it is -17.6‰ in fluid inclusion CO2 and -23.6‰ in graphite from the host rock. The δ34S values of pyrite are -2.6 to -7.9‰. The strongly to moderately negative carbon isotope composition of the carbonates and inclusion fluid CO2 reflects variable contribution of organic carbon to an originally heavier fluid (magmatic, metamorphic, or mantle-derived) at the site

  19. Biomarkers in fluid inclusions: A new tool in constraining source regimes and its implications for the genesis of Mississippi Valley-type deposits

    NASA Astrophysics Data System (ADS)

    Etminan, Hashem; Hoffmann, Christopher F.

    1989-01-01

    Biomarkers in fluid inclusions can constrain source regimes for hydrocarbons associated with Mississippi Valley-type Pb-Zn deposits. Significant amounts of hydrocarbons have been detected in fluid inclusions in sphalerite and dolomite intimately associated with Pb-Zn sulfides in the Canning Basin, Western Australia. The hydrocarbons are more mature than those in the host rocks to the ore and are therefore derived from an external source. Furthermore, there are differences between the biomarker components of hydrocarbons in inclusions in Pb-Zn prospects, but they are all different from hydrocarbons in organic-rich strata and also in oils from the Canning Basin. Yet, the hydrocarbons are mature and oil-like, suggesting that mature organic-rich strata deeper in the basin, which are less significant as potential source rocks for petroleum generation in the Canning Basin, have contributed to the ore-forming fluids.

  20. Raman and micro-thermometric investigation of the fluid inclusions in quartz in a gold-rich formation from Lepaguare mining district (Honduras, Central America).

    PubMed

    Bersani, D; Salvioli-Mariani, E; Mattioli, M; Menichetti, M; Lottici, P P

    2009-08-01

    Fluid inclusions in the quartz crystals present in gold-rich veins from central Honduras have been studied by means of micro-thermometry and micro-Raman spectroscopy in order to provide information on the physico-chemical conditions and chemical composition of the mineralizing fluids. The use of a confocal micro-Raman apparatus allowed to obtain information on the fluid composition, in particular on the gas phase, minimizing the contributions of the host matrix to the Raman signal. The samples studied were collected from an area (Lepaguare mining district, Northern-Central Honduras) rich in ore deposits due to the Cenozoic magmatic activity, where the gold and sulphide mineralization is connected with a system of quartz veins (few decimetres thick) occurring in low-grade metamorphic rocks and produced by hydrothermal fluids. The quartz crystals present in the gold-rich veins often contain fluid inclusions. Four types of fluid inclusions have been observed, but their assemblage in the same clusters and fracture systems, as well as their comparable salinity and homogenization data, suggest that they have the same origin. Micro-thermometry and Raman spectroscopy provide a composition of the mineralizing fluids attributable to the system H(2)O-NaCl-KCl-CO(2)-CH(4), with temperature and pressure intervals of 210-413 degrees C and 1050-3850 bar, respectively. These data agree with an epigenetic origin of the gold deposit (depth < 6 km) related to granitoid or granodiorite intrusions associated to orogenic environments.

  1. Raman and micro-thermometric investigation of the fluid inclusions in quartz in a gold-rich formation from Lepaguare mining district (Honduras, Central America)

    NASA Astrophysics Data System (ADS)

    Bersani, D.; Salvioli-Mariani, E.; Mattioli, M.; Menichetti, M.; Lottici, P. P.

    2009-08-01

    Fluid inclusions in the quartz crystals present in gold-rich veins from central Honduras have been studied by means of micro-thermometry and micro-Raman spectroscopy in order to provide information on the physico-chemical conditions and chemical composition of the mineralizing fluids. The use of a confocal micro-Raman apparatus allowed to obtain information on the fluid composition, in particular on the gas phase, minimizing the contributions of the host matrix to the Raman signal. The samples studied were collected from an area (Lepaguare mining district, Northern-Central Honduras) rich in ore deposits due to the Cenozoic magmatic activity, where the gold and sulphide mineralization is connected with a system of quartz veins (few decimetres thick) occurring in low-grade metamorphic rocks and produced by hydrothermal fluids. The quartz crystals present in the gold-rich veins often contain fluid inclusions. Four types of fluid inclusions have been observed, but their assemblage in the same clusters and fracture systems, as well as their comparable salinity and homogenization data, suggest that they have the same origin. Micro-thermometry and Raman spectroscopy provide a composition of the mineralizing fluids attributable to the system H 2O-NaCl-KCl-CO 2-CH 4, with temperature and pressure intervals of 210-413 °C and 1050-3850 bar, respectively. These data agree with an epigenetic origin of the gold deposit (depth < 6 km) related to granitoid or granodiorite intrusions associated to orogenic environments.

  2. Raman and micro-thermometric investigation of the fluid inclusions in quartz in a gold-rich formation from Lepaguare mining district (Honduras, Central America).

    PubMed

    Bersani, D; Salvioli-Mariani, E; Mattioli, M; Menichetti, M; Lottici, P P

    2009-08-01

    Fluid inclusions in the quartz crystals present in gold-rich veins from central Honduras have been studied by means of micro-thermometry and micro-Raman spectroscopy in order to provide information on the physico-chemical conditions and chemical composition of the mineralizing fluids. The use of a confocal micro-Raman apparatus allowed to obtain information on the fluid composition, in particular on the gas phase, minimizing the contributions of the host matrix to the Raman signal. The samples studied were collected from an area (Lepaguare mining district, Northern-Central Honduras) rich in ore deposits due to the Cenozoic magmatic activity, where the gold and sulphide mineralization is connected with a system of quartz veins (few decimetres thick) occurring in low-grade metamorphic rocks and produced by hydrothermal fluids. The quartz crystals present in the gold-rich veins often contain fluid inclusions. Four types of fluid inclusions have been observed, but their assemblage in the same clusters and fracture systems, as well as their comparable salinity and homogenization data, suggest that they have the same origin. Micro-thermometry and Raman spectroscopy provide a composition of the mineralizing fluids attributable to the system H(2)O-NaCl-KCl-CO(2)-CH(4), with temperature and pressure intervals of 210-413 degrees C and 1050-3850 bar, respectively. These data agree with an epigenetic origin of the gold deposit (depth < 6 km) related to granitoid or granodiorite intrusions associated to orogenic environments. PMID:19117796

  3. Physicochemical conditions and timing of rodingite formation: evidence from rodingite-hosted fluid inclusions in the JM Asbestos mine, Asbestos, Québec

    PubMed Central

    2007-01-01

    Fluid inclusions and geological relationships indicate that rodingite formation in the Asbestos ophiolite, Québec, occurred in two, or possibly three, separate episodes during thrusting of the ophiolite onto the Laurentian margin, and that it involved three fluids. The first episode of rodingitization, which affected diorite, occurred at temperatures of between 290 and 360°C and pressures of 2.5 to 4.5 kbar, and the second episode, which affected granite and slate, occurred at temperatures of between 325 and 400°C and pressures less than 3 kbar. The fluids responsible for these episodes of alteration were moderately to strongly saline (~1.5 to 6.3 m eq. NaCl), rich in divalent cations and contained appreciable methane. A possible third episode of alteration is suggested by primary fluid inclusions in vesuvianite-rich bodies and secondary inclusions in other types of rodingite, with significantly lower trapping temperatures, salinity and methane content. The association of the aqueous fluids with hydrocarbon-rich fluids containing CH4 and higher order alkanes, but no CO2, suggests strongly that the former originated from the serpentinites. The similarities in the composition of the fluids in all rock types indicate that the ophiolite had already been thrust onto the slates when rodingitization occurred. PMID:17961257

  4. Physicochemical conditions and timing of rodingite formation: evidence from rodingite-hosted fluid inclusions in the JM Asbestos mine, Asbestos, Québec.

    PubMed

    Normand, Charles; Williams-Jones, Anthony E

    2007-01-01

    Fluid inclusions and geological relationships indicate that rodingite formation in the Asbestos ophiolite, Québec, occurred in two, or possibly three, separate episodes during thrusting of the ophiolite onto the Laurentian margin, and that it involved three fluids. The first episode of rodingitization, which affected diorite, occurred at temperatures of between 290 and 360 degrees C and pressures of 2.5 to 4.5 kbar, and the second episode, which affected granite and slate, occurred at temperatures of between 325 and 400 degrees C and pressures less than 3 kbar. The fluids responsible for these episodes of alteration were moderately to strongly saline (approximately 1.5 to 6.3 m eq. NaCl), rich in divalent cations and contained appreciable methane. A possible third episode of alteration is suggested by primary fluid inclusions in vesuvianite-rich bodies and secondary inclusions in other types of rodingite, with significantly lower trapping temperatures, salinity and methane content. The association of the aqueous fluids with hydrocarbon-rich fluids containing CH4 and higher order alkanes, but no CO2, suggests strongly that the former originated from the serpentinites. The similarities in the composition of the fluids in all rock types indicate that the ophiolite had already been thrust onto the slates when rodingitization occurred. PMID:17961257

  5. Physicochemical conditions and timing of rodingite formation: evidence from rodingite-hosted fluid inclusions in the JM Asbestos mine, Asbestos, Québec.

    PubMed

    Normand, Charles; Williams-Jones, Anthony E

    2007-10-25

    Fluid inclusions and geological relationships indicate that rodingite formation in the Asbestos ophiolite, Québec, occurred in two, or possibly three, separate episodes during thrusting of the ophiolite onto the Laurentian margin, and that it involved three fluids. The first episode of rodingitization, which affected diorite, occurred at temperatures of between 290 and 360 degrees C and pressures of 2.5 to 4.5 kbar, and the second episode, which affected granite and slate, occurred at temperatures of between 325 and 400 degrees C and pressures less than 3 kbar. The fluids responsible for these episodes of alteration were moderately to strongly saline (approximately 1.5 to 6.3 m eq. NaCl), rich in divalent cations and contained appreciable methane. A possible third episode of alteration is suggested by primary fluid inclusions in vesuvianite-rich bodies and secondary inclusions in other types of rodingite, with significantly lower trapping temperatures, salinity and methane content. The association of the aqueous fluids with hydrocarbon-rich fluids containing CH4 and higher order alkanes, but no CO2, suggests strongly that the former originated from the serpentinites. The similarities in the composition of the fluids in all rock types indicate that the ophiolite had already been thrust onto the slates when rodingitization occurred.

  6. Application of a new Raman microprobe spectrometer to nondestructive analysis of sulfate and other ions in individual phases in fluid inclusions in minerals

    USGS Publications Warehouse

    Rosasco, G.J.; Roedder, E.

    1979-01-01

    Rosasco et al. (1975), reported the first successful application of laser-excited Raman spectroscopy for the identification and nondestructive partial analysis of individual solid, liquid, and gaseous phases in selected fluid inclusions. We report here the results of the application of a new instrument, based on back-scattering, that eliminates many of the previous stringent sample limitations and hence greatly expands the range of applicability of Raman spectroscopy to fluid inclusions. Fluid inclusions in many porphyry copper deposits contain 5-10 ??m 'daughter' crystals thought to be anhydrite but too small for identification by the previous Raman technique. Using the new instrument, we have verified that such daughter crystals in quartz from Bingham, Utah, are anhydrite. They may form by leakage of hydrogen causing internal autooxidation of sulfide ion. Daughter crystals were also examined in apatite (Durango, Mexico) and emerald (Muzo, Colombia). Valid analyses of sulfur species in solution in small fluid inclusions from ore deposits would be valuable, but are generally impossible by conventional methods. We present a calibration procedure for analyses for SO42- in such inclusions from Bingham, Utah (12,000 ?? 4000 ppm) and Creede, Colo. (probably < 500 ppm). A fetid Brazilian quartz, originally thought to contain liquid H2S, is shown to contain only HS- in major amounts. ?? 1979.

  7. Fluid inclusion and stable isotopes studies of epithermal gold-bearing veins in the SE Afar Rift (Djibouti)

    NASA Astrophysics Data System (ADS)

    Moussa, N.; Boiron, M. C.; Grassineau, N.; Fouquet, Y.; Le Gall, B.; Mohamed, J.

    2015-12-01

    The Afar rift results from the interaction of a number of actively-propagating tectono-magmatic axes. Recent field investigations in the SE Afar rift have emphasized the importance of hydrothermal system in rift-related volcanic complexes. Mineralization occur as gold-silver bearing veins and are associated with felsic volcanism. Late carbonate veins barren of sulfides and gold are common. The morphologies and textures of quartz show crustiform colloform banding, massive and breccias. Microthermometric measurements were made on quartz-hosted two phases (liquid + vapor) inclusions; mean homogenization temperature range from 150°C to 340°C and ice-melting temperatures range from -0.2° to 1.6°C indicating that inclusion solutions are dilute and contain 0.35 to 2.7 equivalent wt. % NaCl. Furthermore, δ18O and δ13C values from calcite range from 3.7 to 26.6 ‰ and -7.5 to 0.3‰, respectively. The presence of platy calcite and adularia indicate that boiling condition existed. This study shows that precious-metal deposition mainly occurred from hydrothermal fluids at 200°C at around 300 and 450 m below the present-day surface in a typical low-sulphidation epithermal environment.

  8. The effect of fluid and deformation on zoning and inclusion patterns in poly-metamorphic garnets

    NASA Astrophysics Data System (ADS)

    Erambert, Muriel; Austrheim, Håkon

    1993-11-01

    Within the Bergen Arcs of W Norway, Caledonian eclogite facies assemblages ( T≥650°C, P≥15 kbar) have formed from Grenvillian granulites ( T= 800 900°C, P≥10 kbar) along shear zones and fluid pathways. Garnets in the granulites (grtI: Pyr56 40 Alm45 25Gro19 14) are unzoned or display a weak (ca. 1 wt% FeO over 1000μm) zoning. The eclogite facies rocks contain garnets inherited from their granulite facies protoliths. These relict garnets have certain areas with compositions identical to the garnets in their nearby granulite, but can be crosscut by bands of a more Almrich composition (grtII: Pyr31 41Alm40 47Gro17 21) formed during the eclogite facies event. These bands, orientated preferentially parallel or perpendicular to the eclogite foliation, may contain mineral filled veins or trails of eclogite-facies minerals (omphacite, amphibole, white mica, kyanite, quartz and dolomite). Steep compositional gradients (up to 9 wt% FeO over 40 μm) separate the two generations of garnets, indicating limited volume diffusion. The bands are interpreted as fluid rich channels where element mobility must have been infinitely greater than it was for the temperature controlled volume diffusion at mineral interfaces in the granulites. The re-equilibration of granulite facies garnets during the eclogite facies event must, therefore, be a function of fracture density (deformation) and fluid availability. The results cast doubts on modern petrological and geochronological methods that assume pure temperature controlled chemical re-equilibration of garnets.

  9. Stable isotope systematics and fluid inclusion studies in the Cu-Au Visconde deposit, Carajás Mineral Province, Brazil: implications for fluid source generation

    NASA Astrophysics Data System (ADS)

    da Costa Silva, Antonia Railine; Villas, Raimundo Netuno Nobre; Lafon, Jean-Michel; Craveiro, Gustavo Souza; Ferreira, Valderez Pinto

    2015-06-01

    The Cu-Au Visconde deposit is located in the Carajás Mineral Province (CMP), northern Brazil, near the contact between the ca. 2.76 Ga metavolcano-sedimentary rocks of the Itacaiunas Supergroup rocks and the ~3.0 Ga granitic-gneissic basement. It is hosted by mylonitized Archean rocks, mainly metadacites, the Serra Dourada granite, and gabbros/diorites, which have been successively altered by sodic, sodic-calcic-magnesian, potassic, and calcic-magnesian hydrothermal processes, producing diverse mineralogical associations (albite-scapolite; albite-actinolite-scapolite-epidote; K-feldspar-biotite; chlorite-actinolite-epidote-calcite, etc.). Chalcopyrite is the dominant ore mineral and occurs principally in breccias and veins/veinlets. The aqueous fluids responsible for the alteration/mineralization were initially hot (>460 °C) and very saline (up to 58 wt.% equivalent (equiv.) NaCl), but as the system evolved, they experienced successive dilution processes. Mineral oxygen and hydrogen isotope data show that 18O-rich ( to +9.4 ‰) fluids prevailed in the earlier alteration (including magnetitites) and reached temperatures as high as 410-355 °C. Metamorphic/formation waters, most likely derived from the Carajás Basin rocks, appear to have contributed a major component to the fluid composition, although some magmatic input cannot be discounted. In turn, the later alterations and the mineralization involved cooler (<230 °C), 18O-depleted ( to +3.7 ‰) and less saline (7-30 wt.% equiv. NaCl) fluids, indicating the influx of meteoric water. Fluid dilution and cooling might have caused abundant precipitation of sulfides, especially as breccia cement. Ore δ 34 S values (+0.5 to +3.4 ‰) suggest a magmatic source for sulfur (from sulfide dissolution in pre-existing igneous rocks). The chalcopyrite Pb-Pb ages (2.73 ± 0.15 and 2.74 ± 0.10 Ga) indicate that the Visconde mineralization is Neoarchean, rather than Paleoproterozoic as previously considered. If so, the

  10. Dynamics of mineral crystallization at inclusion-garnet interface from precipitated slab-derived fluid phase: first in-situ synchrotron x-ray measurements

    NASA Astrophysics Data System (ADS)

    Malaspina, Nadia; Alvaro, Matteo; Campione, Marcello; Nestola, Fabrizio

    2015-04-01

    Remnants of the fluid phase at ultrahigh pressure (UHP) in subduction environments may be preserved as primary multiphase inclusions in UHP minerals. These inclusions are frequently hosted by minerals stable at mantle depths, such as garnet, and show the same textural features as fluid inclusions. The mineral infillings of the solid multiphase inclusions are generally assumed to have crystallized by precipitation from the solute load of dense supercritical fluids equilibrating with the host rock. Notwithstanding the validity of this assumption, the mode of crystallization of daughter minerals during precipitation within the inclusion and/or the mechanism of interaction between the fluid at supercritical conditions and the host mineral are still poorly understood from a crystallographic point of view. A case study is represented by garnet orthopyroxenites from the Maowu Ultramafic Complex (China) deriving from harzburgite precursors metasomatised at ~ 4 GPa, 750 °C by a silica- and incompatible trace element-rich fluid phase. This metasomatism produced poikilitic orthopyroxene and inclusion-rich garnet porphyroblasts. Solid multiphase primary inclusions in garnet display a size within a few tens of micrometers and negative crystal shapes. Infilling minerals (spinel: 10-20 vol.%; amphibole, chlorite, talc, mica: 80- 90 vol.%) occur with constant volume ratios and derive from trapped solute-rich aqueous fluids. To constrain the possible mode of precipitation of daughter minerals, we performed for the first time a single-crystal X-ray diffraction experiment by means of Synchrotron Radiation at DLS-Diamond Light Source. In combination with electron probe microanalyses, this measurement allowed the unique identification of each mineral phase and their reciprocal orientations. We demonstrated the epitaxial relationship between spinel and garnet and between some hydrous minerals. Epitaxy drives a first-stage nucleation of spinel under near-to-equilibrium conditions

  11. Origin of water and mantle-crust interactions on Mars inferred from hydrogen isotopes and volatile element abundances of olivine-hosted melt inclusions of primitive shergottites

    NASA Astrophysics Data System (ADS)

    Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.

    2012-12-01

    Volatile elements have influenced the differentiation and eruptive behavior of Martian magmas and played an important role in the evolution of Martian climate and near-surface environments. However, the abundances of volatiles, and in particular the amount of water in the Martian interior, are disputed. A record of volatile reservoirs is contained in primitive Martian basalts (shergottites). Olivine-hosted melt inclusions from a geochemically depleted shergottite (Yamato 980459, representing a very primitive Martian melt) possess undegassed water with a chondritic and Earth-like D/H ratio (δD≤275‰). Based on volatile measurements in these inclusions, the water content of the depleted shergottite mantle is calculated to be 15-47 ppm, which is consistent with the dry mantle hypothesis. In contrast to D/H in the depleted shergottite, melt from an enriched shergottite (Larkman Nunatak 06319), which either formed by melting of an enriched mantle or by assimilation of crust, exhibits an extreme δD of ˜5000‰, indicative of a surface reservoir (e.g., the Martian atmosphere or crustal hydrosphere). These data provide strong evidence that the Martian mantle had retained the primordial low-δD component until at least the time of shergottite formation, and that young Martian basalts assimilated old Martian crust.

  12. Temporal and spatial distribution of alteration, mineralization and fluid inclusions in the transitional high-sulfidation epithermal-porphyry copper system at Red Mountain, Arizona

    USGS Publications Warehouse

    Lecumberri-Sanchez, Pilar; Newton, M. Claiborne; Westman, Erik C.; Kamilli, Robert J.; Canby, Vertrees M.; Bodnar, Robert J.

    2013-01-01

    Red Mountain, Arizona, is a Laramide porphyry Cu system (PCD) that has experienced only a modest level of erosion compared to most other similar deposits in the southwestern United States. As a result, the upper portion of the magmatic–hydrothermal system, which represents the transition from shallower high-sulfidation epithermal mineralization to deeper porphyry Cu mineralization, is well preserved. Within the Red Mountain system, alteration, mineralization and fluid inclusion assemblages show a systematic distribution in both time and space. Early-potassic alteration (characterized by the minerals biotite and magnetite) is paragenetically earlier than late-potassic alteration (K-feldspar–anhydrite) and both are followed by later phyllic (sericite–pyrite) alteration. Advanced argillic alteration (pyrophyllite–alunite–other clay minerals) is thought to be coeval with or postdate phyllic alteration. Minerals characteristic of advanced argillic alteration are present in the near surface. Phyllic alteration extends to greater depths compared to advanced argillic alteration. Early-potassic and late-potassic alteration are only observed in the deepest part of the system. Considerable overlap of phyllic alteration with both early-potassic and late-potassic alteration zones is observed. The hypogene mineralization contains 0.4–1.2% Cu and is spatially and temporally related to the late-potassic alteration event. Molybdenum concentration is typically In the deepest part of the system, an early generation of low-to-moderate density and salinity liquid + vapor inclusions with opaque daughter minerals is followed in time by halite-bearing inclusions that also contain opaque daughter minerals indicating that an early intermediate-density magmatic fluid evolved to a high-density, high-salinity mineralizing fluid. The increase in density and salinity of fluids with time observed in the deeper parts of the system may be the result of immiscibility (“boiling”) of

  13. Metal-rich fluid inclusions provide new insights into unconformity-related U deposits (Athabasca Basin and Basement, Canada)

    NASA Astrophysics Data System (ADS)

    Richard, Antonin; Cathelineau, Michel; Boiron, Marie-Christine; Mercadier, Julien; Banks, David A.; Cuney, Michel

    2016-02-01

    The Paleoproterozoic Athabasca Basin (Canada) hosts numerous giant unconformity-related uranium deposits. The scope of this study is to establish the pressure, temperature, and composition (P-T-X conditions) of the brines that circulated at the base of the Athabasca Basin and in its crystalline basement before, during and after UO2 deposition. These brines are commonly sampled as fluid inclusions in quartz- and dolomite-cementing veins and breccias associated with alteration and U mineralization. Microthermometry and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) data from five deposits (Rabbit Lake, P-Patch, Eagle Point, Millennium, and Shea Creek) complement previously published data for the McArthur River deposit. In all of the deposits investigated, fluid inclusion salinity is between 25 and 40 wt.% NaCl equiv., with compositions displaying a continuum between a "NaCl-rich brine" end-member (Cl > Na > Ca > Mg > K) and a "CaCl2-rich brine" end-member (Cl > Ca ≈ Mg > Na > K). The CaCl2-rich brine has the highest salinity and shows evidence for halite saturation at the time of trapping. The continuum of compositions between the NaCl-rich brine and the CaCl2-rich brine end-members combined with P-T reconstructions suggest anisothermal mixing of the two brines (NaCl-rich brine, 180 ± 30 °C and 800 ± 400 bars; CaCl2-rich brine, 120 ± 30 °C and 600 ± 300 bars) that occurred under fluctuating pressure conditions (hydrostatic to supra-hydrostatic). However, because the two brines were U bearing and therefore oxidized, brine mixing was probably not the driving force for UO2 deposition. Several scenarios are put forward to account for the Cl-Na-Ca-Mg-K composition of the brines, involving combinations of seawater evaporation, halite dissolution, mixing with a halite-dissolution brine, Mg/Ca exchange by dolomitization, Na/Ca exchange by albitization of plagioclase, Na/K exchange by albitization of K-feldspar, and Mg loss by Mg

  14. Ore genesis of the Weibao lead-zinc district, Eastern Kunlun Orogen, China: constrains from ore geology, fluid inclusion and isotope geochemistry

    NASA Astrophysics Data System (ADS)

    Fang, Jing; Chen, Huayong; Zhang, Li; Zheng, Yi; Li, Dengfeng; Wang, Chengming; Shen, Dengliang

    2015-07-01

    The Weibao lead-zinc district, composed by two deposits named the East Weibao deposit and the West Weibao deposit, respectively, is located in the Qimantagh area, Eastern Kunlun Orogen. Although both controlled by skarn alternation and experienced similar mineralization processes, the East Weibao deposit is dominated by massive ores, while the West Weibao deposit is characterized by banded ores. The ore-forming processes of both the deposits can be divided into four stages including prograde skarn stage, retrograde skarn stage, sulfide stage and carbonate stage. Three types of fluid inclusions, i.e., pure CO2 fluid inclusion (PC-type), CO2-bearing fluid inclusion (C-type) and aqueous types (W-type), have been identified in quartz, calcite and sphalerite from different stages. Noteworthily, only sulfide stage of the East Weibao deposit contains carbonic fluid inclusions, whereas only aqueous fluid inclusions were observed in sulfide stage of the West Weibao deposit. The CO2-rich and aqueous-type fluid inclusions in sulfide stage of the East Weibao deposit were homogenized at temperatures between 263 and 424 °C, concentrating at 360-400 °C, with salinities ranging between 3.2 and 13.6 wt% NaCl eqv.; the W-type fluid inclusions in sulfide stage of the West Weibao deposit were homogenized at temperatures between 228 and 381 °C, concentrating at 280-340 °C, with salinities between 1.6 and 9.0 wt% NaCl eqv.; and the aqueous-type fluid inclusions in carbonate stage in both deposits were homogenized at temperatures between 115 and 336 °C, concentrating at 200-240 °C, with salinities between 0.2 and 5.9 wt% NaCl eqv. The ore-forming fluid in sulfide stage at the East Weibao deposit yielded calculated and δ18D values of 4.2 to 5.6 and -88 to -83 ‰, respectively. The results are 8.8 to 10.8, -99 to -92 ‰ for the sulfide stage at the West Weibao deposit and -1.0 to -0.2, -50 to -45 ‰ for carbonate stages in both deposits. The lead isotopic ratios of sulfide

  15. Fluid inclusions in the Harney Peak Granite, Black Hills, South Dakota, USA: Implications for solubility and evolution of magmatic volatiles and crystallization of leucogranite magmas

    NASA Astrophysics Data System (ADS)

    Nabelek, Peter I.; Ternes, Kim

    1997-04-01

    Experimental and theoretical studies have shown that magmatic fluids have strong influence on phase equilibria of granitic systems. A microthermometric study of fluid inclusions in the Proterozoic Harney Peak Granite, Black Hills, South Dakota, USA, was undertaken to obtain direct evidence for the composition and evolution of magmatic fluids in a leucogranitic system and to evaluate their effect on liquid-lines-of-descent of leucogranite magmas. A previous stable isotopic study has demonstrated that the granite has not interacted with nonmagmatic fluids since its crystallization. Therefore, fluids found in the inclusions are of magmatic origin and present an opportunity to directly sample magmatic fluids trapped during crystallization of a granitic magma and during subsolidus conditions. The Harney Peak Granite was emplaced as multiple sills, dikes, and small intrusions, many of which differentiated into coupled aplite-pegmatite layers. Three types of fluid inclusions are found in the granite. Type 1 consist of variable saline H 2OC0 2 mixtures with minor CH 4 or other gases. Inclusions of this type are found in tourmaline and quartz in aplite layers, are generally isolated, and have negative crystal shapes. They are interpreted to be primary. There is a general increase in salinity and decrease in isochore temperature with decreasing CO 2/H 2O ratio of the inclusions. The trend is ascribed to progressive change in fluid composition with crystallization due to the differential solubility of CO 2 and H 2O in the high-silica magma. Isochores, coupled with independently determined crystallization temperatures, suggest entrapment pressure ˜3.5 kbar, consistent with geobarometry in the wallrocks. Type 2 inclusions are carbonic fluids dominated by CO 2, whereas type 3 inclusions are saline aqueous fluids without a detected carbonic component. Both types are mostly found along healed fractures in quartz. They are interpreted to be secondary inclusions that formed as a

  16. Geochemistry and fluid inclusions across a crustal strike-slip Mesozoic fault: insights of fluid-flow / rock interaction in the Atacama Fault System

    NASA Astrophysics Data System (ADS)

    Gomila, R.; Mitchell, T. M.; Arancibia, G.; Jensen, E.; Rempe, M.; Cembrano, J. M.; Hoshino, K.; Faulkner, D.

    2012-12-01

    presence of H2O-rich clays (and gypsum) in the boundary of the fault core represented as fault gouge zones while in the cataclastic zone, the decrease in L.O.I, is explained by the presence of epidote minerals. XRD analyses show a background chloritic alteration. These preliminary analyses give an insight into the evolution of the fault zone in which, at an early stage a cataclasite-rich core is formed and, as deformation continues, a gouge-bounded core is developed. The JF is likely to have had an evolving permeability structure with time with the later stage development of these gouge-rich zones acting as a fluid-barrier for hydrothermal fluids passing across the JF. Fluid inclusions of two quartz veins within the damage zone were analyzed. The results show primary L-V type FI, no boiling evidence, with a wide range of homogenization temperatures (Th) from 119 to 230 °C with variable low salinities of 0,5 - 9,3 (wt% NaCleq.). This is consistent with fluids found in epithermal systems. FONDECYT Project 1100464 is funding this research.

  17. Enhanced dissolution, stability and physicochemical characterization of ATRA/2-hydroxypropyl-β-cyclodextrin inclusion complex pellets prepared by fluid-bed coating technique.

    PubMed

    Chen, Zhongjian; Lu, Yi; Qi, Jianping; Wu, Wei

    2013-02-01

    The aim of this work was to prepare stable all-trans-retinoic acid (ATRA)/2-hydroxypropyl-β-cyclodextrin (HPCD) inclusion complex pellets with industrial feasible technology, the fluid-bed coating technique, using PVP K30 simultaneously as binder and reprecipitation retarder. The coating process was fluent with high coating efficiency. In vitro dissolution of the inclusion complex pellets in 5% w/v Cremopher EL solution was dramatically enhanced with no reprecipitation observed, and significantly improved stability against humidity (92.5% and 75% RH) and illumination (4500 lx ± 500 lx) was achieved by HPCD inclusion. Differential scanning calorimetry and powder X-ray diffractometry confirmed the absence of crystallinity of ATRA. Fourier transform-infrared spectrometry revealed interaction between ATRA and HPCD adding evidence on inclusion of ATRA moieties into HPCD cavities. Solid-state (13)C NMR spectrometry indicated possible inclusion of ATRA through the polyene chain, which was the main reason for the enhanced photostability. It is concluded that the fluid-bed coating technique has the potential use in the industrial preparation of ATRA/HPCD inclusion complex pellets. PMID:22304703

  18. Thermal regimes in the detachment fault environment as deduced from fluid inclusions

    NASA Technical Reports Server (NTRS)

    Beane, R. E.; Wilkins, J., Jr.; Heidrick, T. L.

    1985-01-01

    Extensional tectonism, which dominates middle- and late-Tertiary geology in western Arizona, southeastern California, and southern Nevada, is characterized by normal regionally extensive, low-angle detachment faults. The decollement movement of Fupper plate rocks relative to lower plate assemblages created extensive zones of dilatency, including synthetic and antithetic listric normal faults, tear faults, tectonic crush breccias, shatter breccias, and gash veins in lithologic units above and below the detachment. The tectonically enhanced permeability above and below the detachment fault permitted mass migration of large volumes of hydrothermal solutions along the fault zone during and following upper plate movement. Major quantities of MgO, CaO, K2O, FeO/Fe2O3, SiO2 and CO2 were added to rocks in and near the detachment and related structures. Also introduced were varying amounts of trace elements including Mn, Cu, S, Mo, Ba, Au, Pb, Zn, U and/or Ag. Minerals containing fluid incusions were collected from all of these loci at locations in detachment faulted terranes in western Arizona and southeastern California.

  19. Triple isotope (δD, δ17O, δ18O) study on precipitation, drip water and speleothem fluid inclusions for a Western Central European cave (NW Switzerland)

    NASA Astrophysics Data System (ADS)

    Affolter, Stéphane; Häuselmann, Anamaria D.; Fleitmann, Dominik; Häuselmann, Philipp; Leuenberger, Markus

    2015-11-01

    Deuterium (δD) and oxygen (δ18O) isotopes are powerful tracers of the hydrological cycle and have been extensively used for paleoclimate reconstructions as they can provide information on past precipitation, temperature and atmospheric circulation. More recently, the use of 17Oexcess derived from precise measurement of δ17O and δ18O gives new and additional insights in tracing the hydrological cycle whereas uncertainties surround this proxy. However, 17Oexcess could provide additional information on the atmospheric conditions at the moisture source as well as about fractionations associated with transport and site processes. In this paper we trace water stable isotopes (δD, δ17O and δ18O) along their path from precipitation to cave drip water and finally to speleothem fluid inclusions for Milandre cave in northwestern Switzerland. A two year-long daily resolved precipitation isotope record close to the cave site is compared to collected cave drip water (3 months average resolution) and fluid inclusions of modern and Holocene stalagmites. Amount weighted mean δD, δ18O and δ17O are -71.0‰, -9.9‰, -5.2‰ for precipitation, -60.3‰, -8.7‰, -4.6‰ for cave drip water and -61.3‰, -8.3‰, -4.7‰ for recent fluid inclusions respectively. Second order parameters have also been derived in precipitation and drip water and present similar values with 18 per meg for 17Oexcess whereas d-excess is 1.5‰ more negative in drip water. Furthermore, the atmospheric signal is shifted towards enriched values in the drip water and fluid inclusions (Δ of ˜ + 10‰ for δD). The isotopic composition of cave drip water exhibits a weak seasonal signal which is shifted by around 8-10 months (groundwater residence time) when compared to the precipitation. Moreover, we carried out the first δ17O measurement in speleothem fluid inclusions, as well as the first comparison of the δ17O behaviour from the meteoric water to the fluid inclusions entrapment in speleothems

  20. A reinterpretation of the δDH2O of inclusion fluids in contemporaneous quartz and sphalerite, Creede mining district, Colorodo: a generic problem for shallow orebodies?

    USGS Publications Warehouse

    Foley, Nora K.; Bethke, Philip M.; Rye, Robert O.

    1989-01-01

    The unusually high contrast between the salinities of the ore-depositing fluids and the ground water overlying the ore zone allowed recognition of this phenomenon at Creede. It is likely, however, that Creede is not unique. Similar phenomena may be common in shallow ore zones where rapid fluctuation of an interface between a deep, high-temperature thermal plume and an overlying, cooler ground water may be expected to occur. Careful study of the origins of fluid inclusions, particularly in quartz, is essential to characterize the primary ore fluids and to assess the role of ground water in the hydrology of shallow ore deposits.

  1. The major-ion composition of Cenozoic seawater: the past 36 million years from fluid inclusions in marine halite

    USGS Publications Warehouse

    Brennan, Sean T.; Lowenstein, Tim K.; Cendon, Dioni I.

    2013-01-01

    Fluid inclusions from ten Cenozoic (Eocene-Miocene) marine halites are used to quantify the major-ion composition (Mg2+, Ca2+, K+, Na+, SO42−, and Cl−) of seawater over the past 36 My. Criteria used to determine a seawater origin of the halites include: (1) stratigraphic, sedimentologic, and paleontologic observations; (2) Br− in halite; (3) δ34S of sulfate minerals; (4) 87Sr/86Sr of carbonates and sulfates; and (5) fluid inclusion brine compositions and evaporation paths, which must overlap from geographically separated basins of the same age to confirm a “global” seawater chemical signal. Changes in the major-ion chemistry of Cenozoic seawater record the end of a systematic, long term (>150 My) shift from the Ca2+-rich, Mg2+- and SO42−-poor seawater of the Mesozoic (“CaCl2 seas”) to the “MgSO4 seas” (with higher Mg2+ and SO42−>Ca2+) of the Cenozoic. The major ion composition of Cenozoic seawater is calculated for the Eocene-Oligocene (36-34 Ma), Serravallian-Tortonian (13.5-11.8 Ma) and the Messinian (6-5 Ma), assuming chlorinity (565 mmolal), salinity, and the K+ concentration (11 mmolal) are constant and the same as in modern seawater. Fluid inclusions from Cenozoic marine halites show that the concentrations of Mg2+and SO42− have increased in seawater over the past 36 My and the concentration of Ca2+ has decreased. Mg2+ concentrations increased from 36 mmolal in Eocene-Oligocene seawater (36-34 Ma) to 55 mmolal in modern seawater. The Mg2+/Ca2+ ratio of seawater has risen from ∼2.3 at the end of the Eocene, to 3.4 and 4.0, respectively, at 13.5 to 11.8 Ma and 6 to 5 Ma, and to 5 in modern seawater. Eocene-Oligocene seawater (36-34 Ma) has estimated ranges of SO42− = 14–23 mmolal and Ca2+ = 11–20 mmolal. If the (Ca2+)(SO42−) product is assumed to be the same as in modern seawater (∼300 mmolal2), Eocene-Oligocene seawater had Ca2+ ∼16 mmolal and SO42− ∼19 mmolal. The same estimates of Ca2+ and SO42− for Serravallian

  2. Abundance and isotope systematics of carbon in subglacial basalts, geothermal gases and fluids from Iceland's rift zones

    NASA Astrophysics Data System (ADS)

    Barry, P. H.; Hilton, D. R.; Fueri, E.; Halldorsson, S. A.; Fischer, T. P.; Gronvold, K.

    2010-12-01

    P. H. BARRY1*, D. R. HILTON1, E. FÜRI1, S.A. HALLDÓRSON1, T.P. FISCHER2, K. GRONVOLD3 1 Scripps Institution of Oceanography, UCSD, La Jolla, California 92093, USA (*Correspondence: pbarry@ucsd.edu). 2University of New Mexico, Albuquerque, NM 87131, USA. 3University of Iceland, Askja, Sturlugata 7, IS-101, Reykjavik, Iceland Carbon dioxide (CO2) is the dominant non-aqueous volatile species found in oceanic basalts and geothermal fluids and serves as the carrier gas for trace volatiles such as He and other noble gases. The aim of this study is to identify the superimposed effects of degassing and crustal contamination on the CO2 systematics of the Icelandic hotspot in order to reveal and characterize the carbon abundance and isotopic features of the underlying mantle source. Our approach involves coupling CO2 with He, utilizing the sensitivity of 3He/4He ratios to reveal mantle and crustal inputs. We report new C-isotope (δ13C) and abundance characteristics for a suite of 47 subglacial basalts and 50 geothermal gases and fluids from Iceland. CO2 contents in hyaloclastite glasses are extremely low (10-100 ppm) and likely residual following extensive degassing whereas geothermal fluids are dominated by CO2 (>90 %). C-isotopes range from -27.2 to -3.6 ‰ (vs. PDB) for basalts and from -18.8 to 2.86 ‰ (vs. PDB) for geothermal samples (mean = -4.2 ± 3.6 ‰). CO2/3He ratios range from 108 to 1012 for basalts and from 105 to 1012 for geothermal samples: In both cases, our results extend He-CO2 relationships over a much broader range than reported previously [1]. Taken together, these data suggest that several processes including mixing, degassing, and/or syn- or post-eruptive crustal contamination may act to modify CO2 source characteristics. Equilibrium degassing models are compatible with ~75 % of the basalt data, and preliminary results indicate that initial Icelandic source characteristics are ~500 ppm CO2 and δ13C ~ -5 ‰ (vs. PDB). These values are high

  3. Mineralogical and fluid inclusion constraints on the evolution of the Plaka intrusion-related ore system, Lavrion, Greece

    NASA Astrophysics Data System (ADS)

    Voudouris, P.; Melfos, V.; Spry, P. G.; Bonsall, T.; Tarkian, M.; Economou-Eliopoulos, M.

    2008-05-01

    The intrusion-centered, polymetallic Plaka ore system, Lavrion, Greece, is genetically related to the emplacement of a Miocene biotite ± hornblende granodioritic body and granodiorite porphyry dikes/sills within metamorphic Mesozoic rocks of the Attic-Cycladic Crystalline Belt. The ore system includes porphyry, breccia-type, skarn, skarn-free carbonate replacement and vein-type ores enriched in Mo, W, Pb, Zn, Cu, As, Sb, Bi and Ag. Early pyrite-molybdenite (±chalcopyrite ± pyrrhotite) mineralization was deposited in multidirectional and sheeted quartz veins within the silicically and sericitically altered granodiorite intrusive. The emplacement of granodiorite porphyry dikes/sills was followed by the introduction of base metal sulphides during hydrothermal brecciation of the porphyritic rocks. Skarn- and skarn-free carbonate replacement ores developed contemporaneously with these magmatic-hydrothermal events and are characterized by the presence of pyrrhotite, pyrite, Fe-rich sphalerite and Bi-Ag-rich galena. A late Pb-As-Sb-Cu-Ag-rich banded vein (Filoni 80) is composed of pyrrhotite, chalcopyrite, arsenopyrite, sphalerite (both Fe-rich and Fe-poor), löllingite, argentian tetrahedrite, bournonite, pyrargyrite, miargyrite, native arsenic, semseyite, heteromorphite, veenite, falkmanite and fluorite, quartz and siderite. The ore mineralogy of the Plaka deposit is generally consistent with reducing and low sulphidation fluid conditions during metal deposition. Fluid inclusion data indicate that molybdenite deposition was associated with boiling between 270 and 360 °C and at a pressure of 50-200 bars, corresponding to a depth of approximately 1 km. Dilution of a saline fluid by mixing with less saline water resulted in the formation of a moderately saline (14-18 wt% NaCl equiv.), low-temperature (190-220 °C) fluid and the precipitation of sulphides and sulphosalts in the Filoni 80 vein. The evolution from early porphyry-style mineralization to the later vein ores

  4. Formation of Archean batholith-hosted gold veins at the Lac Herbin deposit, Val-d'Or district, Canada: Mineralogical and fluid inclusion constraints

    NASA Astrophysics Data System (ADS)

    Rezeau, Hervé; Moritz, Robert; Beaudoin, Georges

    2016-07-01

    The Lac Herbin deposit consists of a network of mineralized, parallel steep-reverse faults within the synvolcanic Bourlamaque granodiorite batholith at Val-d'Or in the Archean Abitibi greenstone belt. There are two related quartz-tourmaline-carbonate fault-fill vein sets in the faults, which consist of subvertical fault-fill veins associated with subhorizontal veins. The paragenetic sequence is characterized by a main vein filling ore stage including quartz, tourmaline, carbonate, and pyrite-hosted gold, chalcopyrite, tellurides, pyrrhotite, and cubanite inclusions. Most of the gold is located in fractures in deformed pyrite and quartz in equilibrium with chalcopyrite and carbonates, with local pyrrhotite, sphalerite, galena, cobaltite, pyrite, or tellurides. Petrography and microthermometry on quartz from the main vein filling ore stage reveal the presence of three unrelated fluid inclusion types: (1) gold-bearing aqueous-carbonic inclusions arranged in three-dimensional intragranular clusters in quartz crystals responsible for the main vein filling stage, (2) barren high-temperature, aqueous, moderately saline inclusions observed in healed fractures, postdating the aqueous-carbonic inclusions, and considered as a remobilizing agent of earlier precipitated gold in late fractures, and (3) barren low-temperature, aqueous, high saline inclusions in healed fractures, similar to the crustal brines reported throughout the Canadian Shield and considered to be unrelated to the gold mineralization. At the Lac Herbin deposit, the aqueous-carbonic inclusions are interpreted to have formed first and to represent the gold-bearing fluid, which were generated contemporaneous with regional greenschist facies metamorphism. In contrast, the high-temperature aqueous fluid dissolved gold from the main vein filling ore stage transported and reprecipitated it in late fractures during a subsequent local thermal event.

  5. Raman spectroscopic measurements of CO2 density: Experimental calibration with high-pressure optical cell (HPOC) and fused silica capillary capsule (FSCC) with application to fluid inclusion observations

    USGS Publications Warehouse

    Wang, X.; Chou, I.-Ming; Hu, W.; Burruss, R.C.; Sun, Q.; Song, Y.

    2011-01-01

    Raman spectroscopy is a powerful method for the determination of CO2 densities in fluid inclusions, especially for those with small size and/or low fluid density. The relationship between CO2 Fermi diad split (??, cm-1) and CO2 density (??, g/cm3) has been documented by several previous studies. However, significant discrepancies exist among these studies mainly because of inconsistent calibration procedures and lack of measurements for CO2 fluids having densities between 0.21 and 0.75g/cm3, where liquid and vapor phases coexist near room temperature.In this study, a high-pressure optical cell and fused silica capillary capsules were used to prepare pure CO2 samples with densities between 0.0472 and 1.0060g/cm3. The measured CO2 Fermi diad splits were calibrated with two well established Raman bands of benzonitrile at 1192.6 and 1598.9cm-1. The relationship between the CO2 Fermi diad split and density can be represented by: ??=47513.64243-1374.824414????+13.25586152????2-0.04258891551????3 (r2=0.99835, ??=0.0253g/cm3), and this relationship was tested by synthetic fluid inclusions and natural CO2-rich fluid inclusions. The effects of temperature and the presence of H2O and CH4 on this relationship were also examined. ?? 2011 Elsevier Ltd.

  6. Fluid inclusions in Ebelyakh diamonds: Evidence of CO2 liberation in eclogite and the effect of H2O on diamond habit

    NASA Astrophysics Data System (ADS)

    Smith, Evan M.; Kopylova, Maya G.; Frezzotti, Maria Luce; Afanasiev, Valentin P.

    2015-02-01

    Fluid inclusions were studied in six octahedrally-grown, eclogitic diamonds from the Ebelyakh River mine, northern Russia, using microthermometry and Raman spectroscopy. The fluids are CO2-N2 mixtures with 40 ± 4 mol% N2, which are trapped along fractures that healed in the diamond stability field. The CO2-rich composition of the fluids provides the first empirical evidence that CO2 can be liberated as a free phase in eclogite in the diamond stability field of the lithospheric mantle, as has been previously predicted from theory. This finding means that the interpretation of carbon isotopes in eclogitic diamonds should not overlook isotopic fractionation due to CO2 liberation from carbonatitic diamond-forming media as it percolates through eclogites. Preferential nucleation of CO2 bubbles in eclogite compared to peridotite may lead to a rock type-specific fracturing mechanism and sampling bias that would help explain the overabundance of eclogite xenoliths in kimberlites. Fluid inclusions in octahedrally-grown, non-fibrous diamonds from both the studied Ebelyakh diamonds and those from other cratons do not show detectable amounts of water. In comparison, fibrous diamond fluid inclusions typically contain 10-25 wt.% water. The absence of "dry" fluids in fibrous diamonds and the presence of these in octahedrally-grown diamonds may indicate different compositions of fluids equilibrated with these two types of diamonds. If there is variability in the water content in diamond-forming fluids, it should affect diamond growth morphology. Water could be responsible for causing fibrous diamond growth, by inhibiting the advancement of growth steps within octahedral faces.

  7. Abiogenic Fischer-Tropsch synthesis of hydrocarbons in alkaline igneous rocks; fluid inclusion, textural and isotopic evidence from the Lovozero complex, N.W. Russia

    NASA Astrophysics Data System (ADS)

    Potter, Joanna; Rankin, Andrew H.; Treloar, Peter J.

    2004-08-01

    A detailed fluid inclusion study has been carried out on the hydrocarbon-bearing fluids found in the peralkaline complex, Lovozero. Petrographic, microthermometric, laser Raman and bulk gas data are presented and discussed in context with previously published data from Lovozero and similar hydrocarbon-bearing alkaline complexes in order to further understand the processes which have generated these hydrocarbons. CH 4-dominated inclusions have been identified in all Lovozero samples. They occur predominantly as secondary inclusions trapped along cleavage planes and healed fractures together with rare H 2O-dominant inclusions. They are consistently observed in close association with either arfvedsonite crystals, partially replaced by aegirine, aegirine crystals or areas of zeolitization. The majority of inclusions consist of a low-density fluid with CH 4 homogenisation temperatures between -25 and -120 °C. Those in near-surface hand specimens contain CH 4+H 2 (up to 40 mol%)±higher hydrocarbons. However, inclusions in borehole samples contain CH 4+higher hydrocarbons±H 2 indicating that, at depth, higher hydrocarbons are more likely to form. Estimated entrapment temperatures and pressures for these inclusions are 350 °C and 0.2-0.7 kbar. A population of high-density, liquid, CH 4-dominant inclusions have also been recorded, mainly in the borehole samples, homogenising between -78 and -99 °C. These consist of pure CH 4, trapped between 1.2 and 2.1 kbar and may represent an early CH 4-bearing fluid overprinted by the low-density population. The microthermometric and laser Raman data are in agreement with bulk gas data, which have recorded significant concentrations of H 2 and higher hydrocarbons up to C 6H 12 in these samples. These data, combined with published isotopic data for the gases CH 4, C 2H 6, H 2, He and Ar indicate that these hydrocarbons have an abiogenic, crustal origin and were generated during postmagmatic, low temperature, alteration reactions of

  8. Carbon isotope and abundance systematics of Icelandic geothermal gases, fluids and subglacial basalts with implications for mantle plume-related CO2 fluxes

    NASA Astrophysics Data System (ADS)

    Barry, P. H.; Hilton, D. R.; Füri, E.; Halldórsson, S. A.; Grönvold, K.

    2014-06-01

    We report new carbon dioxide (CO2) abundance and isotope data for 71 geothermal gases and fluids from both high-temperature (HT > 150 °C at 1 km depth) and low-temperature (LT < 150 °C at 1 km depth) geothermal systems located within neovolcanic zones and older segments of the Icelandic crust, respectively. These data are supplemented by CO2 data obtained by stepped heating of 47 subglacial basaltic glasses collected from the neovolcanic zones. The sample suite has been characterized previously for He-Ne (geothermal) and He-Ne-Ar (basalt) systematics (Füri et al., 2010), allowing elemental ratios to be calculated for individual samples. Geothermal fluids are characterized by a wide range in carbon isotope ratios (δ13C), from -18.8‰ to +4.6‰ (vs. VPDB), and CO2/3He values that span eight orders of magnitude, from 1 × 104 to 2 × 1012. Extreme geothermal values suggest that original source compositions have been extensively modified by hydrothermal processes such as degassing and/or calcite precipitation. Basaltic glasses are also characterized by a wide range in δ13C values, from -27.2‰ to -3.6‰, whereas CO2/3He values span a narrower range, from 1 × 108 to 1 × 1012. The combination of both low δ13C values and low CO2 contents in basalts indicates that magmas are extensively and variably degassed. Using an equilibrium degassing model, we estimate that pre-eruptive basaltic melts beneath Iceland contain ∼531 ± 64 ppm CO2 with δ13C values of -2.5 ± 1.1‰, in good agreement with estimates from olivine-hosted melt inclusions (Metrich et al., 1991) and depleted MORB mantle (DMM) CO2 source estimates (Marty, 2012). In addition, pre-eruptive CO2 compositions are estimated for individual segments of the Icelandic axial rift zones, and show a marked decrease from north to south (Northern Rift Zone = 550 ± 66 ppm; Eastern Rift Zone = 371 ± 45 ppm; Western Rift Zone = 206 ± 24 ppm). Notably, these results are model dependent, and selection of a lower

  9. Determination of H2O and CO2 concentrations in fluid inclusions in minerals using laser decrepitation and capacitance manometer analysis

    NASA Technical Reports Server (NTRS)

    Yonover, R. N.; Bourcier, W. L.; Gibson, E. K.

    1985-01-01

    Water and carbon dioxide concentrations within individual and selected groups of fluid inclusions in quartz were analyzed by using laser decrepitation and quantitative capacitance manometer determination. The useful limit of detection (calculated as ten times the typical background level) is about 5 x 10(-10) mol of H2O and 5 x 10(-11) mol of CO2; this H2O content translates into an aqueous fluid inclusion approximately 25 micrometers in diameter. CO2/H2O determinations for 38 samples (100 separate measurements) have a range of H2O amounts of 5.119 x 10(-9) to 1.261 x 10(-7) mol; CO2 amounts of 7.216 x 10(-10) to 1.488 x 10(-8) mol, and CO2/H2O mole ratios of 0.011 to 1.241. Replicate mole ratio determinations of CO2/H2O for three identical (?) clusters of inclusions in quartz have average mole ratios of 0.0305 +/- 0.0041 1 sigma. Our method offers much promise for analysis of individual fluid inclusions, is sensitive, is selective when the laser energy is not so great as to melt the mineral (laser pits approximately 50 micrometers in diameter), and permits rapid analysis (approximately 1 h per sample analysis).

  10. Preservation of methane generated during serpentinization of upper mantle rocks: Evidence from fluid inclusions in the Nidar ophiolite, Indus Suture Zone, Ladakh (India)

    NASA Astrophysics Data System (ADS)

    Sachan, Himanshu K.; Mukherjee, Barun K.; Bodnar, Robert J.

    2007-05-01

    The Nidar Ophiolite Complex (NOC) within the Indus Suture Zone in Eastern Ladakh, India, represents a suprasubduction zone (SSZ) ophiolite from a fore-arc setting. The lower part of the ophiolite sequence is comprised of ultramafic upper mantle rocks that are Mg-rich (Fo in olivine > 90-92) and contain 2-7% Cr-spinel. Pure-methane (CH 4) fluid inclusions occur in olivine from partially serpentinized harzburgite and dunite from the NOC. Homogenization temperatures range from - 160 °C to - 108 °C, and freezing behavior combined with Raman analyses indicate that the inclusions contain no other gaseous species. The majority of the inclusions appear to be of secondary origin although some isolated inclusions of indeterminate origin were observed. CH 4 in the Nidar ophiolite was generated as a by-product of serpentinization of ultramafic rocks in the mantle wedge above the subducting slab, coupled with the complete consumption of water during hydration of serpentine. The presence of the lizardite polymorph of serpentine is consistent with formation in a rock-dominated system (low water activity) that was being deformed in a non-isotropic stress environment. The observed fluid inclusion isochores suggest various degrees of reequlibration during the history of the rocks, with the more extreme (high P) isochores most closely approximating the serpentinization conditions during prograde metamorphism at temperatures < 600 °C and pressures in excess of about 2 kbars. These results support previous studies that have shown that early-formed fluid inclusions in mantle-derived rocks may be preserved during tectonic uplift to the surface and maintain the original mantle chemical signature.

  11. The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications

    USGS Publications Warehouse

    Viets, J.G.; Hofstra, A.H.; Emsbo, P.; Kozlowski, A.

    1996-01-01

    The composition of fluids extracted from ore and gangue sulfide minerals that span most of the paragenesis of the Silesian-Cracow district was determined using a newly developed ion chromatographic (IC) technique. Ionic species determined were Na+, NH+4, Ca2+, Mg2+, K+, Rb+, Sr2+, Ba2+, Cl-, Br-, F-, I-, PO3-4, CO2-3, HS-, S2O2-3, SO2-4, NO-3, and acetate. Mineral samples included six from the Pomorzany mine and one from the Trzebionka mine which are hosted in the Triassic Muschelkalk Formation, and two samples of drill core from mineralized Upper Devonian strata. Nine paragenetically identifiable sulfide minerals occur throughout the Silesian-Cracow district. These include from earliest to latest: early iron sulfides, granular sphalerite, early galena, light-banded sphalerite, galena, dark-banded sphalerite, iron sulfides, late dark-banded sphalerite with late galena, and late iron sulfides. Seven of the minerals were sampled for fluid inclusion analysis in this study. Only the early iron sulfides and the last galena stage were not sampled. Although the number of analyses are limited to nine samples and two replicates and there is uncertainty about the characteristics of the fluid inclusions analyzed, the data show clear temporal trends in the composition of the fluids that deposited these minerals. Fluid inclusions in minerals deposited later in the paragenesis have significantly more K+, Br-, NH+4, and acetate but less Sr2+ than those deposited earlier in the paragenesis. The later minerals are also characterized by isotopically lighter sulfur and significantly more Tl and As in the solid minerals. The change in ore-fluid chemistry is interpreted to reflect a major change in the hydrologic regime of the district. Apparently, the migrational paths of ore fluids from the Upper Silesian basin changed during ore deposition and the fluids which deposited early minerals reacted with aquifers with very different geochemical characteristics than those that deposited

  12. Na-Cl-Br systematics of fluid inclusions from Mississippi Valley-type deposits, Appalachian Basin: Constraints on solute origin and migration paths

    SciTech Connect

    Kesler, S.E.; Martini, A.M.; Appold, M.S.; Walter, L.M.; Huston, T.J.; Furman, F.C.

    1996-01-01

    This study evaluated Na-Cl-Br systematics of fluid inclusion-hosted brines in Mississippi Valley-type (MVT) deposits from the Appalachian Basin. Unlike other geochemical tracers such as lead and strontium isotopes which constrain metal sources, Na-Cl-Br systematics identify sources of brine salinity. Saline formation waters can vary systematically within and between basins with regard to their Na-Cl-Br compositions depending on the importance of halite dissolution relative to retention of subaerially evaporated seawater for the halogen budget. Oil field brine compositions from the Illinois and Appalachian basins are quite distinct in their Na-Cl-Br systematics. Compositions of saline fluid inclusions in MVT deposits generally are consistent with these regional differences. These results shed new light on the extent of regional flow systems and on the geochemical evolution of saline fluids responsible for mineralization. Nearly all fluid inclusions analyzed from the Appalachian MVT deposits have Na/Br and Cl/Br ratios less than modern seawater, consistent with ratios observed in marine brines involved in halite precipitation. The Na-Cl-Br systematics of the brines responsible for Appalachian MVT deposits may be inherited from original marine brines refluxed into the porous carbonate shelf sediments that host these deposits. The Cl/Br and Na/Br ratios of most fluid inclusion-hosted brines from Appalachian MVT sphalerites and fluorites fall into two compositional groups, one from the Lower Cambrian paleoaquifer and another from the Lower Ordovician paleoaquifer. Leachates from most MVT barite deposits form a third compositional group having lower Na/Br and Cl/Br ratios than the other two. Appalachian MVT leachate compositions differ significantly from those in MVT deposits in the Cincinnati arch-midcontinent region suggesting that these two MVT provinces formed from brines of different origin or flow path. 59 refs., 8 figs., 2 tabs.

  13. The La Unión Au ± Cu prospect, Camagüey District, Cuba: fluid inclusion and stable isotope evidence for ore-forming processes

    NASA Astrophysics Data System (ADS)

    Santana, Miriela María Ulloa; Moura, Márcia Abrahão; Olivo, Gema R.; Botelho, Nilson Francisquini; Kyser, T. Kurtis; Bühn, Bernhard

    2011-01-01

    The Camagüey district, Cuba, is known for its epithermal precious metal deposits in a Cretaceous volcanic arc setting. Recently, the La Unión prospect was discovered in the southern part of the district, containing gold and minor copper mineralization interpreted as porphyry type. Mineralization is hosted in a 73.0 ± 1.5 Ma calc-alkaline I-type oxidized porphyry quartz diorite intrusive within volcanic and volcaniclastic rocks of the early Cretaceous Guáimaro Formation. The porphyry is affected by propylitic alteration and crosscut by a network of quartz and carbonate veinlets and veins. Chlorite, epidote, sericite, quartz, and pyrite are the main minerals in the early veins which are cut by late carbonate and zeolite veins. Late barite pseudomorphously replaces pyrite. Gold is associated with pyrite as disseminations in the altered quartz diorite and in the veins, occurring as inclusions or filling fractures in pyrite with 4 g/t Au in bulk samples, and up to 900 ppm Au in in pyrite. Fluid inclusion and oxygen isotope data are consistent with a H2O-NaCl-(KCl) mineralizing fluid, derived from the quartz diorite magma, and trapped at least at 425°C and 1.2 kbar. This primary fluid unmixed into two fluid phases, a hypersaline aqueous fluid and a low-salinity vapor-rich fluid. Boiling during cooling may have played an important role in metal precipitation. Pyrite δ34S values for the La Unión prospect range between 0.71‰ and 1.31‰, consistent with a homogeneous magmatic sulfur source. The fluids in equilibrium with the mineralized rocks have estimated δ18O values from 8‰ to 11.8‰, calculated for a temperature range of 480-505°C. The tectonic environment of the La Unión prospect, its high gold and low copper contents, the physical-chemical characteristics of the mineralizing fluids and the isotopic signature of the alteration minerals and fluids indicate that the La Unión gold mineralization is similar to the porphyry gold type, even though the ore

  14. Constraints on the thermal history of Taylorsville Basin, Virginia, U.S.A., from fluid-inclusion and fission-track analyses: Implications for subsurface geomicrobiology experiments

    USGS Publications Warehouse

    Tseng, H.-Y.; Onstott, T.C.; Burruss, R.C.; Miller, D.S.

    1996-01-01

    Microbial populations have been found at the depth of 2621-2804 m in a borehole near the center of Triassic Taylorsville Basin, Virginia. To constrain possible scenarios for long-term survival in or introduction of these microbial populations to the deep subsurface, we attempted to refine models of thermal and burial history of the basin by analyzing aqueous and gaseous fluid inclusions in calcite/quartz veins or cements in cuttings from the same borehole. These results are complemented by fission-track data from the adjacent boreholes. Homogenization temperatures of secondary aqueous fluid inclusions range from 120?? to 210??C between 2027- and 3069-m depth, with highest temperatures in the deepest samples. The salinities of these aqueous inclusions range from 0 to ??? 4.3 eq wt% NaCl. Four samples from the depth between 2413 and 2931 m contain both two-phase aqueous and one-phase methane-rich inclusions in healed microcracks. The relative CH4 and CO2 contents of these gaseous inclusions was estimated by microthermometry and laser Raman spectroscopy. If both types of inclusions in sample 2931 m were trapped simultaneously, the density of the methane-rich inclusions calculated from the Peng - Robinson equation of state implies an entrapment pressure of 360 ?? 20 bar at the homogenization temperature (162.5 ?? 12.5??C) of the aqueous inclusions. This pressure falls between the hydrostatic and lithostatic pressures at the present depth 2931 m of burial. If we assume that the pressure regime was hydrostatic at the time of trapping, then the inclusions were trapped at 3.6 km in a thermal gradient of ??? 40??C/km. The high temperatures recorded by the secondary aqueous inclusions are consistent with the pervasive resetting of zircon and apatite fission-track dates. In order to fit the fission-track length distributions of the apatite data, however, a cooling rate of 1-2??C/Ma following the thermal maximum is required. To match the integrated dates, the thermal maximum

  15. Crystallization and uplift path of late Variscan granites evidenced by quartz chemistry and fluid inclusions: Example from the Land's End granite, SW England

    NASA Astrophysics Data System (ADS)

    Drivenes, Kristian; Larsen, Rune Berg; Müller, Axel; Sørensen, Bjørn Eske

    2016-05-01

    The megacrystic, coarse-grained granite of the Land's End granitic complex, SW England, has been investigated by analyzing fluid inclusions, trace elements, and cathodoluminescence textures of quartz. By applying the TitaniQ geothermobarometer together with the cathodoluminescence textures, a two-stage emplacement process is proposed. K-feldspar and quartz phenocrysts crystallized in a deep magma chamber at ca. 18-20 km depth. The phenocrysts were transported together with the melt to a shallow emplacement depth at ca. 5-9 km in multiple intrusive events, causing the composite appearance of the granitic complex. This model of emplacement concurs with similar granites from the Erzgebirge. At the emplacement level, the magma exsolved an aqueous fluid with average salinity of 17.3% m/m NaCl and 9.7% m/m CaCl2. Fluids with higher salinities were exsolved deeper in the system, as the magma experienced stages of water saturation and water undersaturation during ascent from the deep magma chamber. The complex fluid inclusion textures are the results of multiple stages of entrapment of aqueous fluids in the host phases as multiple recharge events from the deeper magma chamber supplied fresh melts and aqueous volatiles. Titanium contents in quartz are closely related to the panchromatic cathodoluminescence intensity, and the Al/Ti ratio is reflected by the 3.26 eV/2.70 eV ratio of hyperspectral cathodoluminescence.

  16. The use of fluid inclusions to constrain fault zone pressure, temperature and kinematic history: an example from the Alpi Apuane, Italy

    NASA Astrophysics Data System (ADS)

    Hodgkins, Margaret A.; Stewart, Kevin G.

    1994-01-01

    The Alpi Apuane is a tectonic window that exposes ductilely deformed greenschist facies metaigneous and metasedimentary rocks beneath relatively unmetamorphosed, brittlely deformed sedimentary rocks of the Tuscan nappe. The brecciated fault zone, the 'window fault', separating the two tectonic units was originally described as a simple thrust fault, but has recently been interpreted to have been reactivated as a later extensional detachment. Although evidence for extensional faulting is seen above and below the window fault, the amount of extensional displacement along this fault is unclear. Fluid inclusions from veins cementing the fault breccia were used to estimate the pressures and temperatures during the last fault movement. Minimum pressure estimates obtained from these inclusions range from 105 to 240 MPa. Pressure-corrected trapping temperatures for these fluids range from about 300 to 345°C. These pressures and temperatures indicate that the fault was last active at a depth of about 10 km, assuming a geothermal gradient at the time of 31°C km-1. This rules out complete extensional unroofing of the Alpi Apuane by movement along the window fault. Fluid salinities increase abruptly from the footwall into the fault zone. This pattern suggests that fluids rose from the footwall, entered the fault zone and were channeled within it, leaching salt from the overlying evaporite. The lack of quartz veins above the fault zone indicates that these fluids did not circulate into the overlying Tuscan nappe.

  17. Abundance of volatile and organic species in intermediate temperature fluids from the Von Damm and Piccard deep sea hydrothermal fields, Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    McDermott, J. M.; Seewald, J.; Reeves, E. P.; German, C. R.; Sylva, S. P.; Klein, F.

    2012-12-01

    vent fluids, and imply the presence of a CO2 sink. Von Damm fluid CO2/CH4 ratios are relatively constant at 1.0 to 1.5 (mol/mol) in the higher temperature fluids, and are low compared with CO2/CH4 ratios of 200 to 250 (mol/mol) in the higher temperature Piccard fluids. All vent fluids at Von Damm are enriched in CH4 and longer-chain n-alkanes. Von Damm fluid H2 and H2S abundances are consistent with those at Rainbow and other ultramafic-influenced systems. At the Von Damm vent field, H2 shows non-conservative behavior in intermediate fluids at temperatures ≤114 °C. Such behavior is consistent with previous studies, which attributed non-conservative H2 behavior in ~30 °C vent fluids to microbial consumption (e.g. Von Damm and Lilley, 2004). Similar activity may be occurring at Von Damm. At Piccard, H2 shows non-conservative mixing behavior at temperatures ≤149 °C. H2 depletion at Piccard occurs at higher temperatures than at Von Damm, in excess of the currently known limit for life at 122 °C (Takei et al., 2008), suggesting that abiotic as well as microbial processes may be affecting H2 abundance. Methylated organic compounds, including methanethiol and methanol, were also observed in vent fluids at Piccard and Von Damm, and further organic compound analyses are ongoing.

  18. Calcite Fluid Inclusion, Paragenetic, and Oxygen Isotopic Records of Thermal Event(s) at Yucca Mountain, Nevada

    SciTech Connect

    B. Peterman; R. Moscati

    2000-08-10

    Yucca Mountain, Nevada, is under consideration as a potential high-level radioactive waste repository situated above the water table in 12.7 Ma tuffs. A wealth of textural and geochemical evidence from low-temperature deposits of calcite and silica, indicates that their genesis is related to unsaturated zone (UZ) percolation and that the level of the potential repository has never been saturated. Nonetheless, some scientists contend that thermal waters have periodically risen to the surface depositing calcite and opal in the tuffs and at the surface. This hypothesis received some support in 1996 when two-phase fluid inclusions (FIs) with homogenization temperatures (Th) between 35 and 75 C were reported from UZ calcite. Calcite deposition likely followed closely on the cooling of the tuffs and continues into the present. The paragenetic sequence of calcite and silica in the UZ is early stage calcite followed by chalcedony and quartz, then calcite with local opal during middle and late stages. Four types of FIs are found in calcite assemblages: (1) all-liquid (L); (2) all-vapor (V); (3) 2-phase with large and variable V:L ratios; and (4) a few 2-phase with small and consistent V:L ratios. Late calcite contains no FI assemblages indicating elevated depositional temperatures. In early calcite, the Th of type 4 FIs ranges from {approx} 40 to {approx} 85 C. Such temperatures (sub-boiling) and the assemblage of FIs are consistent with deposition in the UZ. Some delta 18O values < 10 permil in early calcite support such temperatures. Type 4 FIs, however, seem to be restricted to the early calcite stage, during which either cooling of the tuffs or regional volcanism were possible heat sources. Nonetheless, at present there is no compelling evidence of upwelling water as a source for the calcite/opal deposits.

  19. Geochemistry of gases from fluid inclusions within gold-quartz veins in the Chugach and Kenai Mountains, south-central Alaska

    SciTech Connect

    Goldfarb, R.J.; Leach, D.L.; Hofstra, A.H.; Landis, G.P.

    1985-01-01

    Gold-bearing quartz veins within the Valdez Group turbidite sequences of the Chugach and Kenai Mountains are largely restricted to areas of medium-grade greenschist facies. The veins postdate accretion, deformation, and peak regional metamorphism of the Valdez Group. Liquid dominant, low salinity (<5 wt.% NaCl equivalent) fluid inclusions in quartz from four mining districts show homogenization temperatures generally ranging from 210/sup 0/ to 280/sup 0/C. Estimated minimum trapping pressures of 1.5 kbar were obtained from quartz decrepitation data. The authors observations tend to support the theory that ore-forming fluids were derived during regional metamorphism. Microthermometry, Raman spectroscopy, and mass spectrometry were used to analyze the volatile components of fluid inclusions from the four districts. Inclusions adjacent to gold and sulfide grains from each district contained 7-10 mole % CO/sub 2/, 0-2 mole % CH/sub 4/, and 0-2 mole % N/sub 2/. Both a pure CO/sub 2/ volatile phase and CO/sub 2/-N/sub 2/-CH/sub 4/ mixtures were consistently observed within quartz embaying intergrown gold and sulfide grains. Gas solubility data and the observed inclusion homogenization temperatures support minimum trapping pressures in approximate agreement with the quartz decrepitation data. The estimated minimum pressures correspond to a minimum depth of vein development at 3.5-5 km under the condition that fluid pressure equals lithostatic pressure. The ubiquitous presence of appreciable and similar dissolved gases, along with the consistent salinities and homogenization temperatures, provide further support for a regional process of ore genesis.

  20. Retrograde deformation within the Carthage-Colton Zone as recorded by fluid inclusions and feldspar compositions: tectonic implications for the southern Grenville Province

    NASA Astrophysics Data System (ADS)

    Lamb, William M.

    1993-09-01

    The Carthage-Colton Zone (CCZ), located in the northwestern portion of the Proterozoic Adirondack terrane, forms the boundary between the Adirondack lowlands and highlands and is characterized by textures indicative of ductile deformation. Samples from three rock types have been collected from this zone: (1) pyroxene bearing syenite gneisses of the Diana igneous complex; (2) paragneiss samples from near the northwestern boundary of the Diana complex; (3) a quartz-rich metasediment. Feldspar geothermometry performed on the Diana metasyenites shows that porphyroclasts are relict igneous grains that formed at T≈900° C, while dynamic recrystallization occurred at temperatures as low as 470 to 550° C as shown by the compositions of feldspar neoblasts. All samples examined in this study from the CCZ contain a suite of CO2-rich fluid inclusions that are distinctive both texturally and in their microthermometric behavior (Th=-27.7 to-7.1° C) as compared to CO2-rich Adirondack fluid inclusions that do not lie within this zone (Th=-45.9 to +31.0° C). The results from fluid inclusion microthermometry and feldspar geothermometry restrict the conditions of dynamic recrystallization to temperatures and pressures of 400 to 550° C and 3 to 5 kbar. The retrograde pressure-temperature path must pass through these conditions. Similar fluid inclusion results have been obtained from the Parry Sound Shear Zone (PSSZ) which is a Grenvillian shear zone that is located in Southern Ontario (Lamb and Moecher 1992). However, the inferred retrograde P-T paths for these two areas, the CCZ and the PSSZ, are different and this difference may be a result of late deformation along shear zones that are located between the two areas.

  1. Fluid inclusion evidence for boiling at approx. 370/sup 0/C in the stockwork of the Lasail ophiolitic hydrothermal massive sulfide deposit, Oman

    SciTech Connect

    Spooner, E.T.C.; Bray, C.J.

    1985-01-01

    Four samples of stockwork material from DDHnumber9 through the Lasail ophiolitic massive sulfide deposit in Oman were found to contain satisfactory densities of primary fluid inclusion. Primary fluid inclusions in the latter three samples show evidence typical of boiling: (i) variable phase rations, and (ii) inclusions which homogenize into the liquid or vapor phases over the same temperature interval (360/sup 0/C-400/sup 0/C). The pooled data show two salinity populations: one with a modal composition near that of seawater, (3.5 wt.%TDS), and the other characterized by the bulk of the data concentrated between 4.9 and 6.4 equiv. wt.% NaCl (x 1.4-1.8 seawater) with values as high as 8.6 (x 2.5 seawater). The latter high salinities are interpreted to have been produced by the boiling process. For boiling conditions, fluid inclusion homogenization temperatures = trapping temperatures, with some perturbations. Hence, the mode (372/sup 0/C) and range (360/sup 0/C-400/sup 0/C) of the homogenization temperatures for the high salinity population are estimates of the fluid temperatures during ore deposition. The values are at the upper end of the measured range for black smokers. The pressure given by these boiling temperatures is approx. 230 bars, giving an estimate for original seawater depth of approx. 2-2 1/2 km; figures typical of active spreading ridges. The sample from immediately below massive ore (OM2064) shows a lower hom. T range of 330/sup 0/C-350/sup 0/C, no high salinity population, and no evidence for boiling. These observations are interpreted to reflect high level mixing with cold seawater immediately below the original sea floor.

  2. New on-line method for water isotope analysis of fluid inclusions in speleothems using laser absorption spectroscopy: Application to stalagmites from Borneo and Switzerland

    NASA Astrophysics Data System (ADS)

    Affolter, Stéphane; Fleitmann, Dominik; Nele Meckler, Anna; Leuenberger, Markus

    2014-05-01

    Speleothems are recognised as key continental archives for paleoclimate reconstructions. They contain fluid inclusions representing past drip water trapped in the calcite structure. Speleothem can be precisely dated and therefore the oxygen (δ18O) and hydrogen (δD) isotopes of fluid inclusions constitute powerful proxies for paleotemperature or to investigate changes in the moisture source over several interglacial-glacial cycles. To liberate fluid inclusion water and to analyse its isotopic composition, a new online extraction method developed at Bern is used. The principle can be summarised as follows: Prior to crushing, the sample is placed into a copper tube, fixed to the line previously heated to 140° C and flushed with a nitrogen and standard water mixture. Thereafter, the speleothem sample is crushed using a simple hydraulic crushing device and the released water from fluid inclusions is transferred by the nitrogen-standard water mixture flow to a Picarro L1102-i isotopic liquid water and water vapor analyser. The measuring principle is based on wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) technology that allows us to simultaneously monitor hydrogen and oxygen isotopes. Reproducibility of standard water measurements is typically better than 1.5 o for δD and 0.4 o for δ18O. With this method, we successfully analysed δD and δ18O isotopic composition of a stalagmite from Northern Borneo (tropical West Pacific) covering almost two glacial-interglacial cycles from MIS 12 to early MIS 9 (460-330 ka) as well as recent samples from Switzerland and Borneo. These results are used in combination with calcite δ18O to reconstruct paleotemperature. Currently, we are measuring a stalagmite from Milandre cave (Jura, Switzerland) covering the Bølling-Allerød, Younger Dryas cold phase and the Holocene.

  3. Metamorphosed Plio-Pleistocene evaporites and the origins of hypersaline brines in the Salton Sea geothermal system, California: Fluid inclusion evidence

    SciTech Connect

    McKibben, M.A.; Williams, A.E.; Okubo, Susumu )

    1988-05-01

    The Salton Sea geothermal system (SSGS) occurs in Plio-Pleistocene deltaic-lacustrine-evaporite sediments deposited in the Salton Trough, an active continental rift zone. Temperatures up to 365{degree}C and hypersaline brines with up to 26 wt.% TDS are encountered at 1-3 km depth in the sediments, which are undergoing active greenschist facies hydrothermal metamorphism. Previous models for the origins of the Na-Ca-K-Cl brines have assumed that the high salinities were derived mainly from the downward percolation of cold, dense brines formed by low-temperature dissolution of shallow non-marine evaporites. New drillcores from the central part of the geothermal field contain metamorphosed, bedded evaporites at 1 km depth consisting largely of hornfelsic anhydrite interbedded with anhydrite-cemented solution-collapse shale breccias. Fluid inclusions trapped within the bedded and breccia-cementing anhydrite homogenize at 300{degree}C and contain saline Na-Ca-K-Cl brines. Some of the inclusions contain up to 50 vol.% halite, sylvite and carbonate crystals at room temperature, and some halite crystals persist to above 300{degree}C upon laboratory heating. The data are consistent with the trapping of halite-saturated Na-Ca-K-Cl fluids during hydrothermal metamorphism of the evaporites and accompanying solution collapse of interbedded shales. The authors conclude that many of the slat crystals in inclusions are the residuum of bedded evaporitic salt that was dissolved during metamorphism by heated connate fluids.

  4. Brine history indicated by argon, krypton, chlorine, bromine, and iodine analyses of fluid inclusions from the Mississippi Valley type lead-fluorite-barite deposits at Hansonburg, New Mexico

    USGS Publications Warehouse

    Böhlke, J.K.; Irwin, J.J.

    1992-01-01

    Argon, krypton, chlorine, bromine, and iodine were measured in a homogeneous population of high-salinity hydrothermal fluid inclusions from the Tertiary-age Mississippi Valley-type (MVT) lead-fluorite-barite deposits at Hansonburg, New Mexico to establish new types of evidence for the history of both the fluid and the major dissolved salts. Noble gases and halogens in fluid inclusions containing 10-10-10-9 L of brine (Cl = 3 molal) were analyzed by laser microprobe noble-gas mass spectrometry (lmngms) on neutron-irradiated samples. The concentrations of 36Ar (4.7 ?? 10-8 molal) and 84Kr 1.8 ?? 10-9 molal) in the fluid inclusions are equal to those of fresh surface waters in equilibrium with air at approximately 20 ?? 5??. The mole ratios of Br Cl (1.2 ?? 10-4) and I Cl (1-2 ?? 10-6) are among the lowest measured in any natural waters, similar to those of modern brines formed by dissolution of Permian NaCl-bearing evaporites in southeast New Mexico. 40Ar 36Ar ratios (600) are twice that of air, and indicate that the fluid inclusions had excess radiogenic 40Ar (1.4 ?? 10-5 molal) when trapped. The amount of excess 40Ar appears to be too large to have been acquired with Cl by congruent dissolution of halite-bearing evaporites, and possibly too small to have been acquired with Pb by congruent dissolution of granitic basement rocks with Proterozoic KAr ages. From the lmngms data, combined with published Pb and S isotope data, we infer the following sequence of events in the history of the Hansonburg MVT hydrothermal brine: (1) the brine originated as relatively dilute meteoric water, and it did not gain or lose atmospheric Ar or Kr after recharge; (2) the originally dilute fluid acquired the bulk of its Cl and sulfate in the subsurface after recharge by dissolving halite-bearing Permian? marine evaporites; (3) the high salinity brine then acquired most of its Pb and excess radiogenic 40Ar from interactions with aquifer rocks other than evaporites, possibly clastic

  5. The formation of saline mantle fluids by open-system crystallization of hydrous silicate-rich vein assemblages - Evidence from fluid inclusions and their host phases in MARID xenoliths from the central Kaapvaal Craton, South Africa

    NASA Astrophysics Data System (ADS)

    Konzett, Jürgen; Krenn, Kurt; Rubatto, Daniela; Hauzenberger, Christoph; Stalder, Roland

    2014-12-01

    The composition of texturally primary fluid inclusions and their host phases clinopyroxene, K-richterite, and zircon were investigated in two MARID-type (mica-amphibole-rutile-ilmenite-diopside) mantle xenoliths sampled by the Kimberley cluster of Cretaceous kimberlites erupted in the central Kaapvaal Craton, South Africa. P-T conditions of crystallization for the MARID assemblages of 4.2 GPa and 960 °C were estimated based on Ca-in-opx thermometry and the assumption of a 40 mW/m2 geotherm applied to two orthopyroxene-bearing MARIDs collected from the same locality. Cooling/heating stage measurements and Raman spectroscopy indicate a fluid system dominated by H2O-NaCl-MgCl2 with variable total salinities in the range ⩽6.4-32.4 mass% and minor amounts of MgCl2, the latter inferred from the crystallization of MgCl2 × 12H2O during cooling of the inclusions. In addition to liquid and vapour, enstatite, baddeleyite, barite, calcite and a K-Ba-Fe-Cr-titanate were identified as solid phases in opened fluid inclusions, indicating high LIL-(HFS) element concentrations in the saline hydrous fluids prior to solid phase precipitation. The Cl contents of apatite (⩽0.35 wt.%), phlogopite (⩽0.09 wt.%) and K-richterite (⩽0.025 wt.%) follow the enrichment pattern Clap ≫ Clphl > ClKr which is typical for upper mantle rocks. Fluid inclusion-bearing clinopyroxenes show very low H2O contents of ∼45 μg/g which is consistent with a reduced aH2O of the fluids due to the presence of NaCl-MgCl2-SiO2-LILE combined with high fO2 and very low Al3+ contents of the clinopyoxenes. The zircons show a complex compositional zoning with variable and positively correlated Y (⩽1260 μg/g), P (⩽1870 μg/g) and Sc (⩽1373 μg/g) contents, indicating a pretulite-type substitution Si4+ + Zr4+ = P5+ + (Sc, Y, REE)3+. The Sc contents of the zircons are amongst the highest Sc concentrations reported so far for upper mantle silicates. Oxygen isotope analyses of selected zircons yields δ18O

  6. Recovery Act. Sub-Soil Gas and Fluid Inclusion Exploration and Slim Well Drilling, Pumpernickel Valley, Nevada

    SciTech Connect

    Fairbank, Brian D.

    2015-03-27

    Nevada Geothermal Power Company (NGP) was awarded DOE Award DE-EE0002834 in January 2010 to conduct sub-soil gas and fluid inclusion studies and slim well drilling at its Black Warrior Project (now known as North Valley) in Washoe and Churchill Counties, Nevada. The project was designed to apply highly detailed, precise, low-cost subsoil and down-hole gas geochemistry methods from the oil and gas industry to identify upflow zone drilling targets in an undeveloped geothermal prospect. NGP ran into multiple institutional barriers with the Black Warrior project relating to property access and extensive cultural survey requirement. NGP requested that the award be transferred to NGP’s Pumpernickel Valley project, due to the timing delay in obtaining permits, along with additional over-budget costs required. Project planning and permit applications were developed for both the original Black Warrior location and at Pumpernickel. This included obtaining proposals from contractors able to conduct required environmental and cultural surveying, designing the two-meter probe survey methodology and locations, and submitting Notices of Intent and liaising with the Bureau of Land Management to have the two-meter probe work approved. The award had an expiry date of April 30, 2013; however, due to the initial project delays at Black Warrior, and the move of the project from Black Warrior to Pumpernickel, NGP requested that the award deadline be extended. DOE was amenable to this, and worked with NGP to extend the deadline. However, following the loss of the Blue Mountain geothermal power plant in Nevada, NGP’s board of directors changed the company’s mandate to one of cash preservation. NGP was unable to move forward with field work on the Pumpernickel property, or any of its other properties, until additional funding was secured. NGP worked to bring in a project partner to form a joint venture on the property, or to buy the property. This was unsuccessful, and NGP notified

  7. Geological, fluid inclusion and isotopic studies of the Yinshan Cu-Au-Pb-Zn-Ag deposit, South China: Implications for ore genesis and exploration

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Guang; Ni, Pei; Wang, Ru-Cheng; Zhao, Kui-Dong; Chen, Hui; Ding, Jun-Ying; Zhao, Chao; Cai, Yi-Tao

    2013-09-01

    The Yinshan Cu-Au-Pb-Zn-Ag deposit is located in Dexing, South China. Ore bodies are primarily hosted in low-grade phyllite of the Neoproterozoic Shuangqiaoshan Group along EW- and NNW-striking fault zones. Pb-Zn-Ag mineralization is dictated by Jurassic rhyolitic quartz porphyries (ca. 172 Ma), whereas Cu-Au mineralization is associated with Jurassic dacite porphyries (ca. 170 Ma). The main ore minerals are pyrite, chalcopyrite, galena, sphalerite, tetrahedrite-tennatite, gold, silver, and silver sulphosalt, and the principal gangue minerals are quartz, sericite, calcite, and chlorite. Two-phase liquid-rich (type I), two-phase vapor-rich (type II), and halite-bearing (type III) fluid inclusions can be observed in the hydrothermal quartz-sulfides veins. Type I inclusions are widespread and have homogenization temperatures of 187-303 °C and salinities of 4.2-9.5 wt.% NaCl equivalent in the Pb-Zn-Ag mineralization, and homogenization temperatures of 196-362 °C and salinities of 3.5-9.9 wt.% NaCl equivalent in the Cu-Au mineralization. The pervasive occurrence of type I fluid inclusions with low-moderate temperatures and salinities implies that the mineralizing fluids formed in epithermal environments. The type II and coexisting type III inclusions, from deeper levels below the Cu-Au ore bodies, share similar homogenization temperatures of 317-448 °C and contrasting salinities of 0.2-4.2 and 30.9-36.8 wt.% NaCl equivalent, respectively, which indicates that boiling processes occurred. The sulfur isotopic compositions of sulfides (δ34S = -1.7‰ to +3.2‰) suggest a homogeneous magmatic sulfur source. The lead isotopes of sulfides (206Pb/204Pb = 18.01-18.07; 207Pb/204Pb = 15.55-15.57; and 208Pb/204Pb = 38.03-38.12) are consistent with those of volcanic-subvolcanic rocks (206Pb/204Pb = 18.03-18.10; 207Pb/204Pb = 15.56-15.57; and 208Pb/204Pb = 38.02-38.21), indicating a magmatic origin for lead in the ore. The oxygen and hydrogen isotope compositions (δ18O = +7.8

  8. Fluid inclusion gas chemistry as a potential minerals exploration tool: Case studies from Creede, CO, Jerritt Canyon, NV, Coeur d'Alene district, ID and MT, southern Alaska mesothermal veins, and mid-continent MVT's

    USGS Publications Warehouse

    Landis, G.P.; Hofstra, A.H.

    1991-01-01

    Recent advances in instrumentation now permit quantitative analysis of gas species from individual fluid inclusions. Fluid inclusion gas data can be applied to minerals exploration empirically to establish chemical (gas composition) signatures of the ore fluids, and conceptually through the development of genetic models of ore formation from a framework of integrated geologic, geochemical, and isotopic investigations. Case studies of fluid inclusion gas chemistry from ore deposits representing a spectrum of ore-forming processes and environments are presented to illustrate both the empirical and conceptual approaches. We consider epithermal silver-gold deposits of Creede, Colorado, Carlin-type sediment-hosted disseminated gold deposits of Jerritt Canyon, Nevada, metamorphic silver-base-metal veins of the Coeur d'Alene district, Idaho and Montana, gold-quartz veins in accreted terranes of southern Alaska, and the mid-continent base-metal sulfide deposits of Mississippi Valley-Type (MVT's). Variations in gas chemistry determine the redox state of the ore fluids, provide compositional input for gas geothermometers, characterize ore fluid chemistry (e.g., CH4CO2, H2SSO2, CO2/H2S, organic-rich fluids, gas-rich and gas-poor fluids), identify magmatic, meteoric, metamorphic, shallow and deep basin fluids in ore systems, locate upwelling plumes of magmatic-derived volatiles, zones of boiling and volatile separation, interfaces between contrasting fluids, and important zones of fluid mixing. Present techniques are immediately applicable to exploration programsas empirical studies that monitor fluid inclusion gas threshold concentration levels, presence or absence of certain gases, or changes in gas ratios. We suggest that the greater contribution of fluid inclusion gas analysis is in the integrated and comprehensive chemical dimension that gas data impart to genetic models, and in the exploration concepts based on processes and environments of ore formation derived from

  9. Cu-Mo-Au mineralization in Qarachilar area, Qaradagh batholith (NW Iran): Fluid inclusion and stable isotope studies and Re-Os dating

    NASA Astrophysics Data System (ADS)

    Simmonds, Vartan; Moazzen, Mohssen

    2015-04-01

    The Qaradagh batholith is located in NW Iran, neighboring the Meghri-Ordubad granitoid in southern Armenia. This magmatic complex is emplaced in the northwestern part of the Urumieh-Dokhtar magmatic arc, which formed through north-eastward subduction of Neo-Tethyan oceanic crust beneath the central Iranian domain in the late-Mesozoic and early-Cenozoic and hosts most of the porphyry copper deposits and prospects in Iran, such as Sarcheshmeh and Sungun. The Qaradagh batholith is comprised of Eocene-Oligocene intrusive rocks occurring as multi-episode stocks, where the dominant rock type is granodiorite. Hydrothermal alterations have also occurred in these rocks including potassic, phyllic-sericitic, argillic and propylitic alterations and silicification. These alterations are accompanied by vein-type and disseminated Cu, Mo and Au mineralization. The Qarachilar area is located in the central part of the Qaradagh batholith, which hosts mono-mineralic and quartz-sulfide veins and veinlets (several mm to <1 m thick and 50-700 m long) and silicic zones containing Cu-Mo-Au-Ag ore minerals (mainly pyrite, chalcopyrite and molybdenite). Microthermometric studies on the fluid inclusions of quartz-sulfide veins-veinlets show that the salinity ranges between 15-70 wt% NaCl, with the highest peak between 35-40 wt% NaCl. The homogenization temperature for primary 2-phase and multi-phase inclusions ranges between 220 and 540 °C. Two-phase inclusions homogenizing by vapor disappearance have TH values between 280 and 440 °C (mainly between 300 and 360 °C). A few of them homogenize into vapor state with TH values of 440-540 °C. Multi-phase inclusions show 3 types of homogenization. Most of them homogenize by simultaneous disappearance of vapor bubble and dissolution of halite daughter crystal, for which the TH value is 240-420 °C (mostly between 260 and 340 °C). Those homogenizing by halite dissolution show TH values about 220-360 °C and a few homogenizing by vapor

  10. Investigating fossil hydrothermal systems by means of fluid inclusions and stable isotopes in banded travertine: an example from Castelnuovo dell'Abate (southern Tuscany, Italy)

    NASA Astrophysics Data System (ADS)

    Rimondi, Valentina; Costagliola, Pilario; Ruggieri, Giovanni; Benvenuti, Marco; Boschi, Chiara; Brogi, Andrea; Capezzuoli, Enrico; Morelli, Guia; Gasparon, Massimo; Liotta, Domenico

    2016-03-01

    Southern Tuscany (Italy) hosts geothermal anomalies with associated widespread CO2 gas-rich manifestations and active travertine-deposing thermal springs. Geothermal anomalies have been active since the Late Miocene and have led to the formation of widespread Late Miocene-Pleistocene travertine deposits and meso- and epithermal mineralizations. This study investigates the travertine deposit exposed in the Castelnuovo dell'Abate area of southern Tuscany. Here, a fissure-ridge type travertine deposit and its feeding conduits, currently filled with banded calcite veins (i.e. banded travertine), represent a spectacular example of fossil hydrothermal circulation in the peripheral area of the exploited Monte Amiata geothermal field. The Castelnuovo dell'Abate travertine deposit and associated calcite veins were analysed to establish the characteristics of the parent hydrothermal fluids, and the age of this circulation. The focus of the study was on fluid inclusions, rarely considered in travertine studies, but able to provide direct information on the physico-chemical characteristics of the original fluid. Uranium-thorium geochronological data provided further constraints on the: (1) age of tectonic activity; (2) age of the hydrothermal circulation; and (3) evolution of the Monte Amiata geothermal anomaly. Results indicate that brittle deformation (NW- and SE-trending normal to oblique-slip faults) was active during at least the Middle Pleistocene and controlled a hydrothermal circulation mainly characterized by fluids of meteoric origin, and as old as 300-350 ka. This is the oldest circulation documented to date in the Monte Amiata area. The fluid chemical composition is comparable to that of fluids currently exploited in the shallow reservoir of the Monte Amiata geothermal field, therefore suggesting that fluid composition has not changed substantially over time. These fluids, however, have cooled by about 70 °C in the last 300-350 ka, corresponding to a cooling rate

  11. Pressure-temperature-fluid evolution of the Mongolian Altai in the Central Asian Orogenic Belt: evidence from mineral equilibrium modeling and fluid inclusion studies on amphibolite-facies rocks from western Mongolia

    NASA Astrophysics Data System (ADS)

    Zorigtkhuu, O.-E.

    2012-04-01

    The Central Asian Orogenic Belt (CAOB), also known as Altaids, located between the Archean Siberian Craton to the north and the Tarim and North China Cratons to the south, is regarded as one of the largest accretionary and collisional orogen in the world. Detailed petrological studies on the CAOB therefore provide useful information of pressure-temperature (P-T) history of the orogeny as well as the tectonic evolution of East Asia. This study reports detailed petrological data, particularly the results of phase equilibrium modeling and fluid inclusion analysis, of pelitic schists and amphibolites from Bodonch area, southwestern Mongolia, which occupies a significant part of the Paleozoic history of the Altai Orogen in the southwestern margin of the CAOB, and discuss pressure-temperature-fluid evolution of the area. The dominant mineral assemblages of pelitic schist in Bodonch area are garnet + kyanite + staurolite + biotite + plagioclase, garnet + biotite + staurolite + cordierite, and garnet + biotite + sillimanite + plagioclase with quartz and ilmenite, while amphibolite contains calcic amphibole + quartz + plagioclase + garnet + ilmenite assemblage. Application of conventional garnet-biotite and garnet-cordierite geothermometers as well as GASP geobarometer gave metamorphic conditions of 615-635°C/8.2-8.9 kbar from kyanite-bearing pelitic schist samples. Slightly higher P-T condition of 640-690°C/6.3-10.7 kbar was obtained by mineral equilibrium modeling of garnet-kyanite-staurolite and garnet-staurolite-cordierite assemblages using Theriak-Domino software. The calculation was made in the system Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O (NCKFMASH). We constructed a clockwise P-T path staring from high-pressure amphibolite facies condition within the stability field of kyanite (approximately 650°C/9 kbar) possibly through the stability field of sillimanite by post-peak decompressional cooling. Our petrographical observations of fluid inclusions in pelitic schists

  12. Fluid inclusion and vitrinite-reflectance geothermometry compared to heat-flow models of maximum paleotemperature next to dikes, western onshore Gippsland Basin, Australia

    USGS Publications Warehouse

    Barker, C.E.; Bone, Y.; Lewan, M.D.

    1999-01-01

    Nine basalt dikes, ranging from 6 cm to 40 m thick, intruding the Upper Jurassic-Lower Cretaceous Strzelecki Group, western onshore Gippsland Basin, were used to study maximum temperatures (Tmax) reached next to dikes. Tmax was estimated from fluid inclusion and vitrinitereflectance geothermometry and compared to temperatures calculated using heat-flow models of contact metamorphism. Thermal history reconstruction suggests that at the time of dike intrusion the host rock was at a temperature of 100-135??C. Fracture-bound fluid inclusions in the host rocks next to thin dikes ( 1.5, using a normalized distance ratio used for comparing measurements between dikes regardless of their thickness. In contrast, the pattern seen next to the thin dikes is a relatively narrow zone of elevated Rv-r. Heat-flow modeling, along with whole rock elemental and isotopic data, suggests that the extended zone of elevated Rv-r is caused by a convection cell with local recharge of the hydrothermal fluids. The narrow zone of elevated Rv-r found next to thin dikes is attributed to the rise of the less dense, heated fluids at the dike contact causing a flow of cooler groundwater towards the dike and thereby limiting its heating effects. The lack of extended heating effects suggests that next to thin dikes an incipient convection system may form in which the heated fluid starts to travel upward along the dike but cooling occurs before a complete convection cell can form. Close to the dike contact at X/D 1.5. ?? 1998 Elsevier Science B.V. All rights reserved.

  13. Fluid regimes during late stages of a continental collision: Physical, chemical, and stable isotope measurements of fluid inclusions in fissure quartz from a geotraverse through the Central Alps, Switzerland

    SciTech Connect

    Mullis, J. ); Dubessy, J.; Poty, B. ); O'Neil, J. )

    1994-05-01

    Fluid evolution during neo-alpine metamorphism during late stages of the continental collision between Europe and Africa was studied by analyzing fluid inclusions in alpine fissure quartz collected in forty-nine localities along a geotraverse through the Central Alps, Switzerland. The methods employed include microthermometry, micro-Raman spectroscopy, K/Na thermometry, and stable isotope analysis. Early fluid inclusions provide evidence of close to peak metamorphic temperatures of the late Tertiary or neo-alpine metamorphic event. Fluid composition evolved along the geotraverse from north to south as follows: higher hydrocarbons were dominant in the low- and medium-grade diagenetic zones, methane was the main volatile in the high-grade diagenetic and low-grade anchizone, water dominated in the high-grade anchizone and low-grade epizone, with CO[sub 2] > 10 mol% in the high-grade epizone and in the mesozone. Higher hydrocarbons and CH[sub 4] were the products of kerogen maturation and cracking of preexisting petroleum. Large water supplies originated from the dehydration of cooler metasedimentary rocks that were overthrust by crystalline basements of the Lepontines, Aar, and Gotthard massifs. Carbon isotope analyses suggest that the CO[sub 2] component was derived from oxidation of graphitic matter, especially in the vicinity of sulfate-bearing metasediments and from decarbonation reactions. In the Aar and Gotthard massifs as well as in the Helvetic Axen nappe and its underlying North Helvetic flysch, high fluid pressures prevailed and favored nappe transport. By contrast, in the southern Lepontine area, very low early fluid pressures were probably related to dry rocks and scarce metasediments, and to high geothermal gradients that resulted from intense uplift and erosion between 26 and 18 Ma.

  14. Taolin Zn-Pb-fluorite deposit, People's Republic of China: an example of some problems in fluid inclusion research on mineral deposits.

    USGS Publications Warehouse

    Roedder, E.; Howard, K.W.

    1988-01-01

    The ore in this large Zn-Pb-fluorite deposit in NE Hunan Province occurs as open space-filling in a major fault zone between granite and metasedimentary rocks. Following barren, pre-ore quartz, three stages of ore deposition are recognized. Studies on 400 fluid inclusions from all four stages show homogenization T of 120-200oC (av. approx 160o) and salinities of 0-14 wt.% equiv. NaCl (av. 7.7) . These results differ considerably from some previously published sulphur isotopic T (221-344oC), and data for five inclusions that are more saline (9.0-7.7 wt.% equiv. NaCl) and hotter (up to 345oC) (M.A. 85M/2835, 87M/0888).-R.A.H.

  15. Evaluation of nuclear magnetic resonance spectroscopy for determination of deuterium abundance in body fluids: application to measurement of total-body water in human infants

    SciTech Connect

    Rebouche, C.J.; Pearson, G.A.; Serfass, R.E.; Roth, C.W.; Finley, J.W.

    1987-02-01

    Nuclear magnetic resonance (NMR) spectroscopy was used to quantitate abundance of 2H in body water of human infants. This method provides precise measurement of total-body water without the extensive sample preparation requirements of previously described methods for determination of 2H content in body fluids. 2H2O (1 g/kg body weight) was administered to infants and saliva and urine were collected for up to 5 h. An internal standard was added directly to the fluid specimen and 2H enrichment in water was measured by NMR spectroscopy. Working range of deuterium abundance was 0.04-0.32 atom %. Coefficients of variation for saliva samples at 0.20 atom % 2H was 1.97%. 2H content in urine and saliva water reached a plateau by 4 h after administration, and amounts in the two fluids were virtually identical. Mean total-body water determination for six infants was 58.3 +/- 5.8% of body weight (range 53-66%).

  16. Mineralogical, stable isotope, and fluid inclusion studies of spatially related porphyry Cu and epithermal Au-Te mineralization, Fakos Peninsula, Limnos Island, Greece

    NASA Astrophysics Data System (ADS)

    Fornadel, Andrew P.; Voudouris, Panagiotis Ch.; Spry, Paul G.; Melfos, Vasilios

    2012-05-01

    The Fakos porphyry Cu and epithermal Au-Te deposit, Limnos Island, Greece, is hosted in a ~20 Ma quartz monzonite and shoshonitic subvolcanic rocks that intruded middle Eocene to lower Miocene sedimentary basement rocks. Metallic mineralization formed in three stages in quartz and quartz-calcite veins. Early porphyry-style (Stage 1) metallic minerals consist of pyrite, chalcopyrite, galena, bornite, sphalerite, molybdenite, and iron oxides, which are surrounded by halos of potassic and propylitic alteration. Stage 2 mineralization is composed mostly of quartz-tourmaline veins associated with sericitic alteration and disseminated pyrite and molybdenite, whereas Stage 3, epithermal-style mineralization is characterized by polymetallic veins containing pyrite, chalcopyrite, sphalerite, galena, enargite, bournonite, tetrahedrite-tennantite, hessite, petzite, altaite, an unknown cervelleite-like Ag-telluride, native Au, and Au-Ag alloy. Stage 3 veins are spatially associated with sericitic and argillic alteration. Fluid inclusions in quartz from Stage 1 (porphyry-style) mineralization contain five types of inclusions. Type I, liquid-vapor inclusions, which homogenize at temperatures ranging from 189.5°C to 403.3°C have salinities of 14.8 to 19.9 wt. % NaCl equiv. Type II, liquid-vapor-NaCl, Type III liquid-vapor-NaCl-XCl2 (where XCl is an unknown chloride phase, likely CaCl2), and Type IV, liquid-vapor-hematite ± NaCl homogenize to the liquid phase by liquid-vapor homogenization or by daughter crystal dissolution at temperatures of 209.3 to 740.5 °C, 267.6 to 780.8 °C, and 357.9 to 684.2 °C, respectively, and, Type V, vapor-rich inclusions. Stage 2 veins are devoid of interpretable fluid inclusions. Quartz from Stage 3 (epithermal-style) veins contains two types of fluid inclusions, Type I, liquid-vapor inclusions that homogenize to the liquid phase (191.6 to 310.0 °C) with salinities of 1.40 to 9.73 wt. % NaCl equiv., and Type II, vapor-rich inclusions. Mixing

  17. A fluid inclusion and isotopic study of an intrusion-related gold deposit (IRGD) setting in the 380 Ma South Mountain Batholith, Nova Scotia, Canada: evidence for multiple fluid reservoirs

    NASA Astrophysics Data System (ADS)

    Kontak, Daniel J.; Kyser, Kurt

    2011-04-01

    A set of sheeted quartz veins cutting 380 Ma monzogranite at Sandwich Point, Nova Scotia, Canada, provide an opportunity to address issues regarding fluid reservoirs and genesis of intrusion-related gold deposits. The quartz veins, locally with arsenopyrite (≤5%) and elevated Au-(Bi-Sb-Cu-Zn), occur within the reduced South Mountain Batholith, which also has other zones of anomalous gold enrichment. The host granite intruded ( P = 3.5 kbars) Lower Paleozoic metaturbiditic rocks of the Meguma Supergroup, well known for orogenic vein gold mineralization. Relevant field observations include the following: (1) the granite contains pegmatite segregations and is cut by aplitic dykes and zones (≤1-2 m) of spaced fracture cleavage; (2) sheeted veins containing coarse, comb-textured quartz extend into a pegmatite zone; (3) arsenopyrite-bearing greisens dominated by F-rich muscovite occur adjacent the quartz veins; and (4) vein and greisen formation is consistent with Riedel shear geometry. Although these features suggest a magmatic origin for the vein-forming fluids, geochemical studies indicate a more complex origin. Vein quartz contains two types of aqueous fluid inclusion assemblages (FIA). Type 1 is a low-salinity (≤3 wt.% equivalent NaCl) with minor CO2 (≤2 mol%) and has T h = 280-340°C. In contrast, type 2 is a high-salinity (20-25 wt.% equivalent NaCl), Ca-rich fluid with T h = 160-200°C. Pressure-corrected fluid inclusion data reflect expulsion of a magmatic fluid near the granite solidus (650°C) that cooled and mixed with a lower temperature (400°C), wall rock equilibrated, Ca-rich fluid. Evidence for fluid unmixing, an important process in some intrusion-related gold deposit settings, is lacking. Stable isotopic (O, D, S) analyses for quartz, muscovite and arsenopyrite samples from vein and greisens indicate the following: (1) δ18Oqtz = +11.7‰ to 17.8‰ and δ18Omusc = +10.7‰ to +11.2‰; (2) δDmusc = -44‰ to-54‰; and (3) δ34Saspy = +7.8

  18. Solid-state flurbiprofen and methyl-β-cyclodextrin inclusion complexes prepared using a single-step, organic solvent-free supercritical fluid process.

    PubMed

    Rudrangi, Shashi Ravi Suman; Kaialy, Waseem; Ghori, Muhammad U; Trivedi, Vivek; Snowden, Martin J; Alexander, Bruce David

    2016-07-01

    The aim of this study was to enhance the apparent solubility and dissolution properties of flurbiprofen through inclusion complexation with cyclodextrins. Especially, the efficacy of supercritical fluid technology as a preparative technique for the preparation of flurbiprofen-methyl-β-cyclodextrin inclusion complexes was evaluated. The complexes were prepared by supercritical carbon dioxide processing and were evaluated by solubility, differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, practical yield, drug content estimation and in vitro dissolution studies. Computational molecular docking studies were conducted to study the possibility of molecular arrangement of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin. The studies support the formation of stable molecular inclusion complexes between the drug and cyclodextrin in a 1:1 stoichiometry. In vitro dissolution studies showed that the dissolution properties of flurbiprofen were significantly enhanced by the binary mixtures prepared by supercritical carbon dioxide processing. The amount of flurbiprofen dissolved into solution alone was very low with 1.11±0.09% dissolving at the end of 60min, while the binary mixtures processed by supercritical carbon dioxide at 45°C and 200bar released 99.39±2.34% of the drug at the end of 30min. All the binary mixtures processed by supercritical carbon dioxide at 45°C exhibited a drug release of more than 80% within the first 10min irrespective of the pressure employed. The study demonstrated the single step, organic solvent-free supercritical carbon dioxide process as a promising approach for the preparation of inclusion complexes between flurbiprofen and methyl-β-cyclodextrin in solid-state.

  19. The genesis of the amethyst geodes at Artigas (Uruguay) and the paleohydrology of the Guaraní aquifer: structural, geochemical, oxygen, carbon, strontium isotope and fluid inclusion study

    NASA Astrophysics Data System (ADS)

    Morteani, Giulio; Kostitsyn, Y.; Preinfalk, C.; Gilg, H. A.

    2010-06-01

    The amethyst-bearing geodes found in the flood basalts of the Arapey formation at Artigas (Uruguay) were formed as protogeodes by bubbles of CO2-rich basalt-derived fluids. The formation of the celadonite rim and the lining of the geodes by agate followed by quartz and amethyst were driven by the artesian water of the Guaraní aquifer percolating the basalts from below. The temperature of the amethyst formation is estimated from fluid inclusion data to be between 50° and 120°C. Oxygen stable isotope data suggest a crystallization temperature of calcite of about only 24°C. The actual wellhead temperature of the water produced from the Guaraní aquifer in the study area is around 29°C.

  20. Hydrothermal Evolution of the Giant Cenozoic Kadjaran porphyry Cu-Mo deposit, Tethyan metallogenic belt, Armenia, Lesser Caucasus: mineral paragenetic, cathodoluminescence and fluid inclusion constraints

    NASA Astrophysics Data System (ADS)

    Hovakimyan, Samvel; Moritz, Robert; Tayan, Rodrik; Rezeau, Hervé

    2016-04-01

    stockwork. One of them is the east-west-oriented 6th vein zone in the northern part of the deposit, which contains quartz-molybdenite veins and late quartz-galena-sphalerite veins. This is interpreted as a telescoping between porphyry and epithermal environments. It is supported by microscopic studies of mineral paragenesis, which reveal the presence of enargite and tennantite-tetrahedrite, luzonite, sphalerite, and galena, generally in a gangue of quartz, followed by a late carbonate and gypsum stage. On-going fluid inclusion studies are being carried out on quartz samples from the different mineralization stages. Five types of fluid inclusions were distinguished according to their nature, bubble size, and daughter mineral content: vapor-rich, aqueous-carbonic, brine, polyphase brine and liquid-rich inclusions. Cathodoluminescence images from the porphyry veins reveal four generations of quartz. Molybdenite and chalcopyrite are associated with two different dark luminescent quartz generations, which contain typical brine, aqueous-carbonic and vapour-rich H2O fluid inclusions, with some of them coexisting locally as boiling assemblages. Epithermal veins are mainly characterized by liquid-rich H2O fluid inclusions. Microthermometric studies of fluid inclusions reveal a major difference in homogenisation temperatures between the early quartz-molybdenite- chalcopyrite stage (Thtotal between 3600 and 4250C) and the late quartz-galena-sphalerite vein stage (Thtotal 300-2700C), which is attributed to the transition from a porphyry to an epithermal environment in the Kadjaran deposit.

  1. SEM-Cathodoluminescence and fluid inclusion study of quartz veins in Hugo Dummett porphyry Cu-Au deposit,South Mongolia

    NASA Astrophysics Data System (ADS)

    Sanjaa, M.; Fujimaki, H.; Ken-Ichiro, H.

    2010-12-01

    The Hugo Dummett porphyry copper-gold deposit in Oyu Tolgoi, South Mongolia is a high-sulfidation type deposit which consists of Cu-Au bearing quartz veins. Cathodoluminescence (CL) analysis using scanning electron microscope (SEM) and fluid inclusion microthermometer were performed to elucidate the relationship between CL structures, fluid inclusion microthermometer of different quartz generations, and ore forming process of the Hugo Dummett deposit. Hydrothermal quartz from quartz-sulfide veins in the porphyry Cu-Au deposit in Hugo Dummett, revealing the following textures: (1) euhedral growth zones (2) embayed and rounded CL-bright cores, with CL-dark and CL-gray overgrowths, (3) concentric and non concentric growth zones, and (4) CL dark/bright microfractures. These textures indicate that many veins have undergone fracturing, growth of quartz into fluid-filled space and quartz dissolution of quartz. SEM-CL imaging indicates vein quartz in the Hugo Dummett deposit, initially grew as individual CL-bright crystals 356 ± 10°C liquid-reservoir (average Th value for fluid inclusions in the crystal cores is 359°C). In contract, SEM-CL imaging shows the edges of the micron-scale growth zones of varying CL intensity, reflecting quartz precipitation at some later time, when the Hugo Dummett deposit hydrothermal system had cooled, when reservoir conditions were about 211 ± 25°C (average Th value of 212°C). Crystal growth is SEM-CL evidence of the vein quartz having been partly dissolved. Pressure change has a large effect on quartz solubility and may have been responsible for quartz dissolution and precipitation textures in the cooling hydrothermal system. CL-dark microfractures homogenization temperatures lower 169 ± 16°C (average Th value 170°C) than CL bright and CL gray. Temperature and pressure of the mineralized fluid estimates a pressure of formation of 0.3-0.5 kbar (lithostatic), was formed at approximately 2 km depth, as well as a formation temperature

  2. Invisible gold distribution on pyrite and ore-forming fluid process of the Huangshan orogenic-type gold deposit of Zhejiang, SE China: implications from mineralogy, trace elements, impurity and fluid inclusion studies

    NASA Astrophysics Data System (ADS)

    Sundarrajan, Vijay Anand; Li, Zilong; Hu, Yizhou; Fu, Xuheng; Zhu, Yuhuo

    2016-07-01

    The Huangshan orogenic-type gold deposit in Zhejiang of SE China occurred in quartz-pyrite veins. It is hosted by phyllonite that underwent greenschist-facies metamorphism along a large Jiangshan-Shaoxing tectonic belt with a NE-SW direction. Trace elemental characteristics, ore-forming process and invisible gold on different forms of pyrite and quartz are studied. The Au associated pyrite can be classified into two categories; recrystallized pyrite and euhedral pyrite. The precipitation of invisible Au on pyrite is mainly derived by Co and Ni with AuHS2 - complex in the mineralizing fluids in different events. The XPS results revealed that valence states of Au3+ replaced 2Fe2+ in the pyrite and Au0 replaced Si4+ in the quartz structure. The electron paramagnetic resonance and trace elemental results suggested that the element pairs of Ge-Li-Al in quartz and Mn-Co-Ni in pyrite have distinct impurities as identified. A fluid inclusion study showed that the auriferous quartz is characterized by low-saline and CO2-rich fluids. Coexistence of the type I-type III inclusions and same range of homogenization temperature with different mode are evidences of immiscible fluid process. The temperature-pressure values of ca. 250 °C/1250 bar and ca. 220 °C/780 bar for gold precipitation have been calculated by intersection of coexisting fluids during the entrapment. The Huangshan orogenic-type gold deposit may be associated with the Wuyi-Yunkai orogeny during the early Paleozoic, including an upper-mid greenschist-facies metamorphism (450-420 Ma). All the features suggest that the Huangshan gold deposit is probably a product linking with the early Paleozoic orogeny in South China.

  3. Fluid Inclusion characteristics of syn-late orogenic Co-Ni-Cu-Au deposits in the Siegerland District of the Rhenish Massif, Germany

    NASA Astrophysics Data System (ADS)

    Wohlgemuth, Christoph; Hellmann, André; Meyer, Franz Michael

    2013-04-01

    The Siegerland District is located in the fold-and-thrust-belt of the Rhenish Massif and hosts various syn- late orogenic vein-hosted hydrothermal mineralization types. Peak-metamorphism and deformation occurred at 312-316 ± 10 Ma (Ahrendt et al., 1978) at pT-conditions of 280 - 320 °C and 0.7 - 1.4 kbar (Hein, 1993). The district is known for synorogenic siderite-quartz mineralization formed during peak-metamorphic conditions. At least 4 syn-late orogenic mineralization types are distinguished: Co-Ni-Cu-Au, Pb-Zn-Cu, Sb-Au and hematite-digenite-bornite mineralization (Hellmann et al., 2012b). Co-Ni-Cu-Au mineralization of the Siegerland District belongs to the recently defined class of metasediment hosted synorogenic Co-Cu-Au deposits (i.e. Slack et al, 2010). Ore minerals are Fe-Co-Ni sulpharsenides, bearing invisible gold, chalcopyrite, and minor As-bearing pyrite. The gangue is quartz. The alteration mineralogy comprises chlorite, illite-muscovite and quartz. The epigenetic quartz veins are closely related to the formation of reverse faults (Hellmann et al., 2011a). Microthermometric studies of fluid inclusions concerning the relationship between mineralization and microstructures have not been done so far for this deposit-class and this will be addressed here. Fluid inclusions are investigated in hydrothermally formed vein-quartz, selected from Co-Ni-Cu-Au mineralization bearing veins showing only minor overprints by later mineralization types. Two quartz generations are distinguished: subhedral quartz-I showing growth zonation and fine grained, recrystallized- and newly formed quartz-II grains forming irregular masses and fracture fillings in quartz-I. Co-Ni-Fe sulpharsenides and chalcopyrite are closely intergrown with quartz-II, implying their contemperaneous formation. However, fluid inclusions in quartz-II are often small, therefore fluid inclusions in quartz-I have been mostly investigated. In total, 180 inclusions from 4 different deposits have been

  4. Abundance of Cysteine Endopeptidase Dionain in Digestive Fluid of Venus Flytrap (Dionaea muscipula Ellis) Is Regulated by Different Stimuli from Prey through Jasmonates

    PubMed Central

    Libiaková, Michaela; Floková, Kristýna; Novák, Ondřej; Slováková, L'udmila; Pavlovič, Andrej

    2014-01-01

    The trap of the carnivorous plant Venus flytrap (Dionaea muscipula) catches prey by very rapid closure of its modified leaves. After the rapid closure secures the prey, repeated mechanical stimulation of trigger hairs by struggling prey and the generation of action potentials (APs) result in secretion of digestive fluid. Once the prey's movement stops, the secretion is maintained by chemical stimuli released from digested prey. We investigated the effect of mechanical and chemical stimulation (NH4Cl, KH2PO4, further N(Cl) and P(K) stimulation) on enzyme activities in digestive fluid. Activities of β-D-glucosidases and N-acetyl-β-D-glucosaminidases were not detected. Acid phosphatase activity was higher in N(Cl) stimulated traps while proteolytic activity was higher in both chemically induced traps in comparison to mechanical stimulation. This is in accordance with higher abundance of recently described enzyme cysteine endopeptidase dionain in digestive fluid of chemically induced traps. Mechanical stimulation induced high levels of cis-12-oxophytodienoic acid (cis-OPDA) but jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) accumulated to higher level after chemical stimulation. The concentration of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) did not change significantly. The external application of JA bypassed the mechanical and chemical stimulation and induced a high abundance of dionain and proteolytic activity in digestive fluid. These results document the role of jasmonates in regulation of proteolytic activity in response to different stimuli from captured prey. The double trigger mechanism in protein digestion is proposed. PMID:25153528

  5. Abundance of cysteine endopeptidase dionain in digestive fluid of Venus flytrap (Dionaea muscipula Ellis) is regulated by different stimuli from prey through jasmonates.

    PubMed

    Libiaková, Michaela; Floková, Kristýna; Novák, Ondřej; Slováková, L'udmila; Pavlovič, Andrej

    2014-01-01

    The trap of the carnivorous plant Venus flytrap (Dionaea muscipula) catches prey by very rapid closure of its modified leaves. After the rapid closure secures the prey, repeated mechanical stimulation of trigger hairs by struggling prey and the generation of action potentials (APs) result in secretion of digestive fluid. Once the prey's movement stops, the secretion is maintained by chemical stimuli released from digested prey. We investigated the effect of mechanical and chemical stimulation (NH4Cl, KH2PO4, further N(Cl) and P(K) stimulation) on enzyme activities in digestive fluid. Activities of β-D-glucosidases and N-acetyl-β-D-glucosaminidases were not detected. Acid phosphatase activity was higher in N(Cl) stimulated traps while proteolytic activity was higher in both chemically induced traps in comparison to mechanical stimulation. This is in accordance with higher abundance of recently described enzyme cysteine endopeptidase dionain in digestive fluid of chemically induced traps. Mechanical stimulation induced high levels of cis-12-oxophytodienoic acid (cis-OPDA) but jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) accumulated to higher level after chemical stimulation. The concentration of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) did not change significantly. The external application of JA bypassed the mechanical and chemical stimulation and induced a high abundance of dionain and proteolytic activity in digestive fluid. These results document the role of jasmonates in regulation of proteolytic activity in response to different stimuli from captured prey. The double trigger mechanism in protein digestion is proposed. PMID:25153528

  6. Abundance of cysteine endopeptidase dionain in digestive fluid of Venus flytrap (Dionaea muscipula Ellis) is regulated by different stimuli from prey through jasmonates.

    PubMed

    Libiaková, Michaela; Floková, Kristýna; Novák, Ondřej; Slováková, L'udmila; Pavlovič, Andrej

    2014-01-01

    The trap of the carnivorous plant Venus flytrap (Dionaea muscipula) catches prey by very rapid closure of its modified leaves. After the rapid closure secures the prey, repeated mechanical stimulation of trigger hairs by struggling prey and the generation of action potentials (APs) result in secretion of digestive fluid. Once the prey's movement stops, the secretion is maintained by chemical stimuli released from digested prey. We investigated the effect of mechanical and chemical stimulation (NH4Cl, KH2PO4, further N(Cl) and P(K) stimulation) on enzyme activities in digestive fluid. Activities of β-D-glucosidases and N-acetyl-β-D-glucosaminidases were not detected. Acid phosphatase activity was higher in N(Cl) stimulated traps while proteolytic activity was higher in both chemically induced traps in comparison to mechanical stimulation. This is in accordance with higher abundance of recently described enzyme cysteine endopeptidase dionain in digestive fluid of chemically induced traps. Mechanical stimulation induced high levels of cis-12-oxophytodienoic acid (cis-OPDA) but jasmonic acid (JA) and its isoleucine conjugate (JA-Ile) accumulated to higher level after chemical stimulation. The concentration of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) did not change significantly. The external application of JA bypassed the mechanical and chemical stimulation and induced a high abundance of dionain and proteolytic activity in digestive fluid. These results document the role of jasmonates in regulation of proteolytic activity in response to different stimuli from captured prey. The double trigger mechanism in protein digestion is proposed.

  7. Petrographic, fluid inclusion and isotopic study of the Dikulushi Cu-Ag deposit, Katanga (D.R.C.): implications for exploration

    NASA Astrophysics Data System (ADS)

    Haest, Maarten; Muchez, Philippe; Dewaele, Stijn; Boyce, Adrian J.; von Quadt, Albrecht; Schneider, Jens

    2009-07-01

    The Dikulushi Cu-Ag vein-type deposit is located on the Kundelungu Plateau, in the southeastern part of the Democratic Republic of Congo (D.R.C.). The Kundelungu Plateau is situated to the north of the Lufilian Arc that hosts the world-class stratiform Cu-Co deposits of the Central African Copperbelt. A combined petrographic, fluid inclusion and stable isotope study revealed that the mineralisation at Dikulushi developed during two spatially and temporally distinct mineralising episodes. An early Cu-Pb-Zn-Fe mineralisation took place during the Lufilian Orogeny in a zone of crosscutting EW- and NE-oriented faults and consists of a sequence of sulphides that precipitated from moderate-temperature, saline H2O-NaCl-CaCl2-rich fluids. These fluids interacted extensively with the country rocks. Sulphur was probably derived from thermochemical reduction of Neoproterozoic seawater sulphate. Undeformed, post-orogenic Cu-Ag mineralisation remobilised the upper part of the Cu-Pb-Zn-Fe mineralisation in an oxidising environment along reactivated and newly formed NE-oriented faults in the eastern part of the deposit. This mineralisation is dominated by massive Ag-rich chalcocite that precipitated from low-temperature H2O-NaCl-KCl fluids, generated by mixing of moderate- and low-saline fluids. The same evolution in mineralisation assemblages and types of mineralising fluids is observed in three other Cu deposits on the Kundelungu Plateau. Therefore, the recognition of two distinct types of (vein-type) mineralisation in the study area has a profound impact on the exploration in the Kundelungu Plateau region. The identification of a Cu-Ag type mineralisation at the surface could imply the presence of a Cu-Pb-Zn-Fe mineralisation at depth.

  8. Fluid inclusion, rare earth element geochemistry, and isotopic characteristics of the eastern ore zone of the Baiyangping polymetallic Ore district, northwestern Yunnan Province, China

    NASA Astrophysics Data System (ADS)

    Feng, Caixia; Bi, Xianwu; Liu, Shen; Hu, Ruizhong

    2014-05-01

    The Baiyangping Cu-Ag polymetallic ore district is located in the northern part of the Lanping-Simao foreland fold belt, which lies between the Jinshajiang-Ailaoshan and Lancangjiang faults in western Yunnan Province, China. The source of ore-forming fluids and materials within the eastern ore zone were investigated using fluid inclusion, rare earth element (REE), and isotopic (C, O, and S) analyses undertaken on sulfides, gangue minerals, wall rocks, and ores formed during the hydrothermal stage of mineralization. These analyses indicate: (1) The presence of five types of fluid inclusion, which contain various combinations of liquid (l) and vapor (v) phases at room temperature: (a) H2O (l), (b) H2O (l) + H2O (v), (c) H2O (v), (d) CmHn (v), and (e) H2O (l) + CO2 (l), sometimes with CO2 (v). These inclusions have salinities of 1.4-19.9 wt.% NaCl equivalents, with two modes at approximately 5-10 and 16-21 wt.% NaCl equivalent, and homogenization temperatures between 101 °C and 295 °C. Five components were identified in fluid inclusions using Raman microspectrometry: H2O, dolomite, calcite, CH4, and N2. (2) Calcite, dolomitized limestone, and dolomite contain total REE concentrations of 3.10-38.93 ppm, whereas wall rocks and ores contain REE concentrations of 1.21-196 ppm. Dolomitized limestone, dolomite, wall rock, and ore samples have similar chondrite-normalized REE patterns, with ores in the Huachangshan, Xiaquwu, and Dongzhiyan ore blocks having large negative δCe and δEu anomalies, which may be indicative of a change in redox conditions during fluid ascent, migration, and/or cooling. (3) δ34S values for sphalerite, galena, pyrite, and tetrahedrite sulfide samples range from -7.3‰ to 2.1‰, a wide range that indicates multiple sulfur sources. The basin contains numerous sources of S, and deriving S from a mixture of these sources could have yielded these near-zero values, either by mixing of S from different sources, or by changes in the geological

  9. Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba

    SciTech Connect

    Thomas, A.V.; Spooner, E.T. )

    1988-05-01

    Fluid inclusions from the tourmaline phase of alteration of the footwall amphibolite from the Tanco zoned granitic pegmatite lie in the system H{sub 2}O-CH{sub 4}-NaCl-CO{sub 2}. These inclusions contain a liquid and vapor phase at room temperature and develop a second liquid phase on cooling in the range {minus}77 to {minus}95{degree}C: the second liquid and the vapor are methane. Isochores for inclusions showing vapor phase (CH{sub 4}) homogenization were constructed from the equations of Jacobs and Kerrick (1981). The intersections of these isochores with the univariant melting curves for methane clathrate hydrates give estimates of salinity for the inclusions of between 7 and 10 equivalent wt.% NaCl, which are lower than those derived from measurement of the depression of the melting point of ice; a result consistent with salt exclusion by clathrate. The bulk composition of the fluid is estimated to be 91 mol.% H{sub 2}O, 6 mol.% CH{sub 4}, 2 equiv. mol.% NaCl and <1 mol.% CO{sub 2}. Total homogenization temperatures have a mean value of 371{degree}C {plus minus} 36{degree}C. Calculation of f{sub O2} from the bulk inclusion composition gives values near WI at these conditions which is unreasonably low for fluids derived from the pegmatite, which were probably between QFM and HM. The metasomatic fluids may have resulted from fluid mixing in the wall rock immediately adjacent to the pegmatite. The fluid derived from the pegmatite, a H{sub 2}O-CO{sub 2} fluid, introduced the B necessary to form tourmaline in the amphibolite. Supporting evidence is provided by pegmatite wall zone fluids with higher CH{sub 4} than the bulk of the pegmatite H{sub 2}O-CO{sub 2} fluids, suggesting marginal fluid contamination.

  10. Spherical particles of halophilic archaea correlate with exposure to low water activity – implications for microbial survival in fluid inclusions of ancient halite

    PubMed Central

    Fendrihan, S; Dornmayr-Pfaffenhuemer, M; Gerbl, F W; Holzinger, A; Grösbacher, M; Briza, P; Erler, A; Gruber, C; Plätzer, K; Stan-Lotter, H

    2012-01-01

    Viable extremely halophilic archaea (haloarchaea) have been isolated from million-year-old salt deposits around the world; however, an explanation of their supposed longevity remains a fundamental challenge. Recently small roundish particles in fluid inclusions of 22 000- to 34 000-year-old halite were identified as haloarchaea capable of proliferation (Schubert BA, Lowenstein TK, Timofeeff MN, Parker MA, 2010, Environmental Microbiology, 12, 440–454). Searching for a method to produce such particles in the laboratory, we exposed rod-shaped cells of Halobacterium species to reduced external water activity (aw). Gradual formation of spheres of about 0.4 μm diameter occurred in 4 m NaCl buffer of aw ≤ 0.75, but exposure to buffered 4 m LiCl (aw ≤ 0.73) split cells into spheres within seconds, with concomitant release of several proteins. From one rod, three or four spheres emerged, which re-grew to normal rods in nutrient media. Biochemical properties of rods and spheres were similar, except for a markedly reduced ATP content (about 50-fold) and an increased lag phase of spheres, as is known from dormant bacteria. The presence of viable particles of similar sizes in ancient fluid inclusions suggested that spheres might represent dormant states of haloarchaea. The easy production of spheres by lowering aw should facilitate their investigation and could help to understand the mechanisms for microbial survival over geological times. PMID:22804926

  11. Cierco Pb-Zn-Ag vein deposits: Isotopic and fluid inclusion evidence for formation during the mesozoic extension in the pyrenees of Spain

    USGS Publications Warehouse

    Johnson, C.A.; Cardellach, E.; Tritlla, J.; Hanan, B.B.

    1996-01-01

    The Cierco Pb-Zn-Ag vein deposits, located in the central Pyrenees of Spain, crosscut Paleozoic metasedimentary rocks and are in close proximity to Hercynian granodiorite dikes and plutons. Galena and sphalerite in the deposits have average ??34S values of -4.3 and -0.8 per mil (CDT), respectively. Coexisting mineral pairs give an isotopic equilibration temperature range of 89?? to 163??C which overlaps with the 112?? to 198??C range obtained from primary fluid inclusions. Coexisting quartz has a ??18O value of 19 ?? 1 per mil (VSMOW). The fluid which deposited these minerals is inferred to have had ??18OH2o and ??34SH2s values of 5 ?? 1 and -1 ?? 1 per mil, respectively. Chemical and microthermometric analyses of fluid inclusions in quartz and sphalerite indicate salinities of 3 to 29 wt percent NaCl equiv with Na+ and Ca2+ as the dominant cations in solution. The Br/Cl and I/Cl ratios differ from those characteristic of magmatic waters and pristine seawater, but show some similarity to those observed in deep ground waters in crystalline terranes, basinal brines, and evaporated seawater, Barite, which postdates the sulfides, spans isotopic ranges of 13 to 21 per mil, 10 to 15 per mil, and 0.7109 to 0.7123 for ??34S, ??18O, and 87Sr/86Sr, respectively. The three parameters are correlated providing strong evidence that the barites are products of fluid mixing. We propose that the Cierco deposits formed along an extensional fault system at the margin of a marine basin during the breakup of Pangea at some time between the Early Triassic and Early Cretaceous. Sulfide deposition corresponded to an upwelling of hydrothermal fluid from the Paleozoic basement and was limited by the amount of metals carried by the fluid. Barite deposition corresponded to the waning of upward flow and the collapse of sulfate-rich surface waters onto the retreating hydrothermal plume. Calcite precipitated late in the paragenesis as meteoric or marine waters descended into the fault system

  12. Cathodoluminescence investigation and fluid inclusion analyses of hydrothermal quartz in the Erdenetiin Ovoo porphyry Cu-Mo deposit in Northern Mongolia

    NASA Astrophysics Data System (ADS)

    Cha, B.; Lee, I.; Seo, J.; Moon, I.

    2012-12-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) reveals textures in quartz that are not apparent with other methods such as optical microscopy or backscattered electron images. Hydrothermal quartz from quartz-sulfide veins in the Erdenetiin Ovoo porphyry Cu-Mo deposit, Mongolia was analyzed by SEM-CL. They reveal euhedral growth zones with CL-bright and gray, wide CL-dull bands that cut across multiple quartz grains, CL-dark splatters of quartz connected by networks of cobweb-shaped CL-dark quartz with decreasing in luminescence along splatters and grain boundaries, and recrystallization of CL-bright quartz to CL-gray quartz. These cryptic textures indicate that a single vein of molybdenite-quartz vein has undergone at least 4 events: (1) precipitation of CL-bright and CL-gray quartz with euhedral quartz, (2) fracturing and following growth of CL-dull quartz, (3) dissolution along microfractures and following CL-dark precipitation with decreasing in luminescence intensity along microfractures and grain boundaries, and (4) precipitation of pyrite-quartz vein cutting the molybdenite-quartz vein. Fluid inclusions in molybdenite-quartz veins are presented by liquid type, liquid-vapor type (vapor occupies 20 volume %), and liquid-vapor type bearing a solid phase. The liquid-vapor type inclusions within CL-gray quartz of the first event show their homogenization temperatures ranging from 204 to 312°C. Typical homogenization temperatures of porphyry deposits range from 250 to 800°C. Molybdenite-quartz vein in the Erdenetiin Ovoo porphyry system formed through the low temperature hydrothermal processes. Keywords: Erdenetiin Ovoo, hydrothermal, quartz, veins, cathodoluminescence, fluid inclusions

  13. Stability of natural gas in the deep subsurface. Technical progress report. [Composition of gases in fluid inclusions from calcite, quartz, anorthosite and olivine

    SciTech Connect

    Barker, C.

    1986-04-30

    Although present gas reserves are adequate for immediate needs, they will eventually be consumed and exploration for additional reserves will have to be pushed steadily deeper. We have continued to try and establish depth limits for commercial gas accumulations in deep reservoirs using a combined theoretical and experimental approach. Theoretical: The computer program, developed over the last few years for calculating the stabilities of natural gas components in reservoirs of various mineralogies, is running routinely. It finds the minimum free energy in multicomponent (up to 70), multiphase (up to 20) systems for conditions corresponding to temperatures and pressure down to 40,000 ft (12 km). The program has been used to calculate gas composition for a wide range of potential reservoir mineralogy. In addition, some preliminary studies have been carried out to make the program compatible with the widely available microcomputers (''PC's''). Analytical: Fluid inclusions have been used to provide uncontaminated samples of deep gas. The fast-scanning, computer-controlled mass spectrometer system available for analyzing gases in individual fluid inclusions separately, has been used to study a wide range of minerals. Currently, up to 225 inclusions can be analyzed in a 10 mg sample with a dynamic range of approximately 1:10,000. Samples analyzed include: (1) calcite cements from deep sedimentary sections (down to 20,000 ft) which are frequently rich in hydrogen sulfide, (2) deep metamorphic quartz (probably > 50,000 ft) which was very rich in methane, (sometimes > 70%), and (3) mid-ocean ridge basalt plagioclase and Hawaiian olivines, which were high in carbon dioxide with minor water and carbon monoxide. 7 figs., 2 tabs.

  14. Evolution of the magmatic-hydrothermal acid-sulfate system at Summitville, Colorado: Integration of geological, stable-isotope, and fluid-inclusion evidence

    USGS Publications Warehouse

    Bethke, P.M.; Rye, R.O.; Stoffregen, R.E.; Vikre, P.G.

    2005-01-01

    The Summitville Au-Ag-Cu deposit is a classic volcanic dome-hosted high-sulfidation deposit. It occurs in the Quartz Latite of South Mountain, a composite volcanic dome that was emplaced along the coincident margins of the Platoro and Summitville calderas at 22.5??0.5 Ma, penecontemporaneous with alteration and mineralization. A penecontemporaneous quartz monzonite porphyry intrusion underlies the district and is cut and overlain by pyrite-quartz stockwork veins with traces of chalcopyrite and molybdenite. Alteration and mineralization proceeded through three hypogene stages and a supergene stage, punctuated by at least three periods of hydrothermal brecciation. Intense acid leaching along fractures in the quartz latite produced irregular pipes and lenticular pods of vuggy silica enclosed sequentially by alteration zones of quartz-alunite, quartz-kaolinite, and clay. The acid-sulfate-altered rocks host subsequent covellite+enargite/luzonite+chalcopyrite mineralization accompanied by kaolinite, and later barite-base-metal veins, some containing high Au values and kaolinite. The presence of both liquid- and vapor-rich fluid inclusions indicates the episodic presence of a low-density fluid at all levels of the system. In the mineralized zone, liquid-rich fluid inclusions in healed fractures in quartz phenocrysts and in quartz associated with mineralization homogenize to temperatures between 160 and 390 ??C (90% between 190 and 310 ??C), consistent with the range (200-250 ??C) estimated from the fractionation of sulfur isotopes between coexisting alunite and pyrite. A deep alunite-pyrite pair yielded a sulfur-isotope temperature of 390 ??C, marking a transition from hydrostatic to lithostatic pressure at a depth of about 1.5 km. Two salinity populations dominate the liquid-rich fluid inclusions. One has salinities between 0 and 5 wt.% NaCl equivalent; the other has salinities of up to 43 wt.% NaCl equivalent. The occurrence of high-salinity fluid inclusions in vein

  15. Constraints On The Last Stage Of The Exhumation History Of Dabie Shan (china): A Combined Fluid-inclusion And Apatite Fission-track Study

    NASA Astrophysics Data System (ADS)

    Fu, Bin; Andriessen, Paul A. M.

    Numerous published geochronological studies have been focused on rapid subduction and exhumation models for Dabie Shan, one of the largest high- to ultrahigh-pressure (HP UHP) terranes, but the last stage of the exhumation and denudation history is still unknown. A preliminary combined fluid-inclusion and apatite fission-track (AFT) study has been carried out. At least two generations of fluid flow within the UHP eclogites and associated paragneiss and orthogneiss were constrained by early highly saline brines (Ca2+ and/or Na+-rich) and minor pure CO2, and late nearly pure water in quartz veins, consistent with our previous results for host eclogites. All mean AFT ages of host eclogites and gneisses as well as granites are younger than 60 Ma. A granitic mylonite, which is believed to be a boundary between the South UHP Unit and the North Orthogneiss Unit (NOU), gave a relatively young mean AFT age of 36.3 s´ Ma. Combined with published Ar/Ar dating, the AFT ages prove that the last reheating event above 120 zC in Dabie Shan took place in pre-Tertiary. From AFT analysis (ages and lengths, unimodal) and fluid- inclusion homogenization temperature data (Th, all above 120 zC), it is obvious that the Triassic UHP eclogites and gneisses, as well as Cretaceous granite intrusions in NOU, underwent a rapid but differential uplift history. Rapid cooling, for most of the samples, with cooling rates of at least 10 zC/Ma, is observed for the period between 60 and 40 Ma, indicating that the UHP rocks reached near surface temperatures at around 40 Ma. The fast cooling rates support a tectonic uplift event that has brought the samples to the near surface. What is interesting, although not very well constrained by the AFT analysis, is the possibility of a Late Neogene denudation which may tentatively be related to the Himalaya collision and related to Tibet uplift.

  16. [Cryogenic Raman spectroscopic characteristics of NaCl-H2O, CaCl2-H2O and NaCl-CaCl2-H2O: application to analysis of fluid inclusions].

    PubMed

    Mao, Cui; Chen, Yong; Zhou, Yao-Qi; Ge, Yun-Jin; Zhou, Zhen-Zhu; Wang, You-Zhi

    2010-12-01

    Accurately diagnosing the types of the salt and calculating the salinity quantitatively are the significant content of fluid inclusions. The traditional method of testing fluid inclusions salinity is cooling. To overcome the difficulty for observing freezing phase transition, the authors tested the spectrum of NaCl-H2O, CaCl2-H2O and NaCl-CaCl2-H2O systems at -180 degrees C by laser Raman spectroscopy. The result demonstrates that the ratio of peak values has linear relationship with salinity. Calibration curves were established by typical ratio of hydro-halite at 3 420 cm(-1) to the ice at 3 092 cm(-1), and the ratio of antarcticite at 3 432 cm(-1) to the ice at 3 092 cm(-1). The calibration curves have very high correlation coefficient. This method is verified by synthetic hydrocarbon-bearing aqueous fluid inclusions and quartz aqueous fluid inclusions of well Fengshen 6 in Dongying sag. The results of the authors' experiments show that cryogenic Raman spectroscopy can not only identify the types of the salts but also determine the salinity effectively in fluid inclusions.

  17. Geological, fluid inclusion and isotopic studies of the Baiyangping Pb-Zn-Cu-Ag polymetallic deposit, Lanping basin, Yunnan province, China

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Hu; Hou, Zeng-Qian; Song, Yu-Cai; Zhang, Hong-Rui

    2015-11-01

    Baiyangping Pb-Zn-Cu-Ag deposit is located in Lanping basin, northwestern Yunnan province. The deposit is composed of a few ore veins and can be divided into several ore blocks. The ore bodies are primarily hosted in Mesozoic carbonate, sandstone and siltstone along the north-south-striking, NWW-striking and NE-SW-striking fault zones. There are breccia, massive, vein like and disseminated ores. The main ore minerals are sphalerite, galena, gratonite, jordanite, tetrahedrite series minerals, chalcocite, chalcopyrite, realgar, orpiment, bournonite, cobalt-bearing arsenopyrite, argentite, kongsbergite, cobaltine, siegenite. The sizes of fluid inclusions in Baiyangping deposit are generally less than 10 μm and have the shape of round, oval, irregular, etc. The ore-forming fluid system is Ca2+-Na+-K+-Mg2+-Cl--F--NO3- brine system. The freezing temperature of fluid inclusions in mineral deposits ranges from -26.4 to -0.2 °C, average -14.6 °C; the homogenization temperature is concentrated in 120-180 °C, and the salinity is between 0.35 and 24.73 wt% (NaCleq), average 16.9 wt% (NaCleq). δ13CPDB and δ18OSMOW values of hydrothermal calcite range from -4.16‰ to 3‰ and -2.5‰ to 20.4‰, respectively. δ34S values of sulfide minerals range from -10.2‰ to 11.2‰, average 5.6‰. The sulfide samples yield 206Pb/204Pb values of 18.609-18.818, 207Pb/204Pb of 15.548-15.842 and 208Pb/204Pb = 38.514-39.556. C-O-S-Pb isotope compositions of the Baiyangping deposit indicate a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata, the ore-forming fluid belongs to basin brine fluid system, which is mixed with the precipitate water, sulfur in sulfides and sulfosalts is derived from thermal chemical sulfate reduction, and the thermal decomposition of sulfur-bearing organic matter. The metal mineralization material is from sedimentary strata and basement. The late Pb-Zn polymetallic mineralization event

  18. Kuh-e Dom Fe-Cu-Au prospect, Anarak Metallogenic Complex, Central Iran: a geological, mineralogical and fluid inclusion study

    NASA Astrophysics Data System (ADS)

    Tale Fazel, Ebrahim; Mehrabi, Behzad; Tabbakh Shabani, Amir Ali

    2015-02-01

    The Kuh-e Dom Fe-Cu-Au prospect is located in the Urumieh-Dokhtar Magmatic Belt, and is characterized by copper-iron oxide and gold veins, stockworks and breccias hosted by the Eocene Kuh-e Dom arc intrusion. Mineralization is located within NE-SW to WNW-ESE sinistral faults and likely formed in a subduction-related continental margin that is typical of IOCG deposit systems. The deposits have a distinct metal composition of Fe, Cu, Bi, Co, Mo and LREE with gold (up to 3 g/t), and the mineral assemblages are quartz, hematite, pyrite, chalcopyrite, emplectite, magnetite, free gold, calcite, barite, chlorite, and tourmaline. Three paragenetic stages of mineralized quartz veins are distinguished in the Kuh-e Dom prospect, including: (i) hematite-bearing quartz veins, (ii) quartz-sulfide stockwork and breccia veins, and (iii) quartz-calcite±sulfide infilling veins. Sodic (albitization), potassic, and quartz-calcite±chlorite pervasive alterations are commonly associated with these three mineralization stages. Three types of fluid inclusions have been identified at Kuh-e Dom, including: aqueous two-phase (H2O-NaCl-CaCl2±FeCl2), halite-saturated aqueous (H2O-NaCl±KCl), and CO2-bearing (H2O-CO2±CH4 and CO2±CH4) fluid inclusions. A hypersaline (~35 wt% NaCl equiv.), aqueous magmatic fluid was released at about 400 °C and a pressure of nearly 4 kbar, forming early hematite-bearing quartz veins. These high salinity fluids were progressively diluted further away from Kuh-e Dom intrusion due to substantial input of meteoric water and mixing with the magmatic components during the middle and late stages of mineralization. The mineralogy, alteration, and fluid composition of the Kuh-e Dom Fe-Cu-Au prospect compared well with Fe oxide Cu-Au (IOCG) deposits worldwide.

  19. Comparative geochemical, magnetic susceptibility, and fluid inclusion studies on the Paleoproterozoic Malanjkhand and Dongargarh granitoids, Central India and implications to metallogeny

    NASA Astrophysics Data System (ADS)

    Pandit, Dinesh; Panigrahi, Mruganka K.; Moriyama, Takeru; Ishihara, Shunso

    2014-10-01

    The Malanjkhand granodiorite (MG) hosting economic copper mineralization and the hitherto barren Dongargarh granitoids (DG) have subtle differences in their petrographic and bulk geochemical features. The two plutons are contiguous and occur in the northern part of the Bhandara Craton in Central India with intervening volcanosedimentary sequence of the Dongargarh Supergroup amidst older gneisses. The Dongargarh granitoids studied in two smaller units have higher bulk magnetic susceptibility than the Cu-bearing MG; the majority of samples studied from the latter being ilmenite-series rocks. DG crystallized at higher pressures compared to MG. Plagioclase composition ranges from albite to high bytownite in MG, whereas its compositional range is restricted to high andesine in DG. However, both intrusions give identical temperature ranges estimated by binary feldspar thermometry. Biotite in MG shows higher Fe/Mg ratios, as well as a greater range of compositional variation, than that in DG. MG has a moderately fractionated rare earth element distribution pattern without any significant Eu anomaly, showing depletion in mid-range rare earth elements (REE) and no depletion in heavy REE. DG is characterized by a prominent negative Eu anomaly. Geochemical features indicate subtle differences in the nature of source rocks and/or melting processes responsible for the generation of the two granitoids. MG displays more consistent bulk chemical features and is possibly a result of crystallization from a homogeneous granodioritic melt. DG displays a greater diversity and possibly incorporated a significant felsic crustal component that contributed to the parent melt. A fluid inclusion study of quartz grains from the granitoids and barren quartz veins occurring in MG indicates identical low-temperature nature of the fluid in both cases. They differ from the fluid in the mineralized zone in MG in the absence of a high-temperature component and CO2 in the fluid. Late-stage fluids in

  20. Multiscale Abundance and Size Distribution of Inclusions in the Allende CV3 Meteorite by X-Ray Image Analysis of Slabs

    NASA Astrophysics Data System (ADS)

    Ebel, D. S.; Brunner, C. E.; Weisberg, M. K.

    2008-03-01

    Analysis of combined X-ray (CMAS + Fe) and BSE maps of Allende slabs (13 µm/pxl) and sections (4-5 µm/pxl) (>19 mm2) yield higher matrix and AOA, lower CAI abundances than McSween (1977). Size distributions of chondrules and CAIs are similar.

  1. The fluids in salt.

    USGS Publications Warehouse

    Roedder, E.

    1984-01-01

    The characteristics of fluid inclusions in salt, the geological processes through which these fluids evolve, and the possible problems such inclusions pose for nuclear waste disposal in salt beds or domes are reviewed.-J.A.Z.

  2. The mangazeya Ag-Pb-Zn vein deposit hosted in sedimentary rocks, Sakha-Yakutia, Russia: Mineral assemblages, fluid inclusions, stable isotopes (C, O, S), and origin

    NASA Astrophysics Data System (ADS)

    Anikina, E. Yu.; Bortnikov, N. S.; Klubnikin, G. K.; Gamyanin, G. N.; Prokof'ev, V. Yu.

    2016-05-01

    The succession of mineral assemblages, chemistry of gangue and ore minerals, fluid inclusions, and stable isotopes (C, O, S) in minerals have been studied in the Mangazeya silver-base-metal deposit hosted in terrigenous rocks of the Verkhoyansk Fold-Thrust Belt. The deposit is localized in the junction zone of the Kuranakh Anticlinorium and the Sartanga Synclinorium at the steep eastern limb of the Endybal Anticline. The deposit is situated at the intersection of the regional Nyuektame and North Tirekhtyakh faults. Igneous rocks are represented by the Endybal massif of granodiorite porphyry 97.8 ± 0.9 Ma in age and dikes varying in composition. One preore and three types of ore mineralization separated in space are distinguished: quartz-pyrite-arsenopyrite (I), quartz-carbonate-sulfide (II), and silver-base-metal (III). Quartz and carbonate (siderite) are predominant in ore veins. Ore minerals are represented by arsenopyrite, pyrite, sphalerite, galena, fahlore, and less frequent sulfosalts. Three types of fluid inclusions in quartz differ in phase compositions: two- or three-phase aqueous-carbon dioxide (FI I), carbon dioxide gas (FI II), and two-phase (FI III) containing liquid and a gas bubble. The homogenization temperature and salinity fall within the ranges of 367-217°C and 13.8-2.6 wt % NaCl equiv in FI I; 336-126°C and 15.4-0.8 wt % NaCl equiv in FI III. Carbon dioxide in FI II was homogenized in gas at +30.2 to +15.3°C and at +27.2 to 29.0°C in liquid. The δ34S values for minerals of type I range from-1.8 to +4.7‰ (V-CDT); of type II, from-7.4 to +6.6‰; and of type III, from-5.6 to +7.1‰. δ13C and δ18O vary from-7.0 to-6.7‰ (V-PDB) and from +16.6 to +17.1 (V-SMOW) in siderite-I; from-9.1 to-6.9‰ (V-PDB) and from +14.6 to +18.9 (V-SMOW) in siderite-II; from-5.4 to-3.1‰ (V-PDB) and from +14.6 to +19.5 (V-SMOW) in ankerite; and from-4.2 to-2.9‰ (V-PDB) and from +13.5 to +16.8 (V-SMOW) in calcite. The data on mineral assemblages, fluid

  3. Constraining the origin of the Messinian gypsum deposits using coupled measurement of δ^{18}O$/δD in gypsum hydration water and salinity of fluid inclusions

    NASA Astrophysics Data System (ADS)

    Evans, Nicholas P.; Gázquez, Fernando; McKenzie, Judith A.; Chapman, Hazel J.; Hodell, David A.

    2016-04-01

    We used oxygen and hydrogen isotopes of gypsum hydration water (GHW) coupled with salinity deduced from ice melting temperatures of primary fluid inclusions in the same samples (in tandem with 87Sr/86Sr, δ34S and other isotopic measurements) to determine the composition of the mother fluids that formed the gypsum deposits of the Messinian Salinity Crisis from shallow and intermediate-depth basins. Using this method, we constrain the origin of the Messinian Primary Lower Gypsum (PLG) of the Sorbas basin (Betic foreland) and both the Upper Gypsum (UG) and the Lower Gypsum of the Sicilian basin. We then compare these results to measurements made on UG recovered from the deep Ionian and Balearic basins drilled during DSDP Leg 42A. The evolution of GHW δ18O/δD vs. salinity is controlled by mixing processes between fresh and seawater, coupled with the degree of evaporation. Evaporation and subsequent precipitation of gypsum from fluids dominated by freshwater will result in a depressed 87Sr/86Sr values and different trajectory in δ18O/δD vs. salinity space compared to fluids dominated by seawater. The slopes of these regression equations help to define the end-members from which the fluid originated. For example, salinity estimates from PLG cycle 6 in the Sorbas basin range from 18 to 51ppt, and after correction for fractionation factors, estimated δ18O and δD values of the mother water are low (-2.6 < δ18O < 2.7‰ ; -16.2 < δD < 15.8‰). The intercepts of the regression equations (i.e. at zero salinity) are within error of the average isotope composition of the modern precipitation and groundwater in this region of SE Spain. This indicates there was a significant contribution of meteoric water during gypsum deposition, while 87Sr/86Sr (0.708942 < 87Sr/86Sr < 0.708971) indicate the ions originated from the dissolution of previously marine evaporites. Gypsum from cycle 2 displays similar mother water values (-2.4 < δ18O < 2.4‰ ; -13.2 < δD < 17.0‰) to

  4. A stable isotope and fluid inclusion study of minor Upper Mississipi Valley-type sulfide mineralization in Iowa, Illinois, and Wisconsin

    SciTech Connect

    Kutz, K.B.

    1988-07-01

    The Upper Mississippi Valley (UMV) zinc-lead district, one of the largest mining districts in the United States, is surrounded by a broad zone of minor base metal mineralization which encompasses approximately 100,000 km/sup 2/ in northwest Illinois, eastern Iowa, and southwest Wisconsin. Over 60 minor base metal occurrences of possible UMV type have been recognized in the outlying zone. However, a genetic link between the outlying mineralization and the ore deposits of the main UMV district has not been firmly established. Although many of the outlying mineral occurrences exhibit close similarities to the main UMV ore deposits, paragenetic, fluid inclusion, and stable isotope (S, C, O, and H) data suggest major differences in the genetic history of the outlying occurrences.

  5. Comment on Fluid inclusion studies of the Rodeo de Los Molles REE and Th deposit, Las Chacras Batholith, central Argentina' by R. Lira and E. M. Ripley

    SciTech Connect

    Williams-Jones, A.E.; Wood, S.A. )

    1991-07-01

    This paper is in response to an earlier paper by R. Lira and E. M. Ripley. This paper acknowledges the significant contribution the previous authors made to the understanding of the physiochemical conditions attending hydrothermal rare earth element (REE) mineralization. They conclude, however, that there is a general lack of information on the conditions of deposition of bastnaesite, which is the principal ore mineral in most REE deposits. It is their opinion that the behavior of the aqueous-carbonic fluid inclusions in fluorite is more complex than those reported by the former authors. They are concerned that the actual temperature and pressure of formation for the assemblage bastnaesite-fluorite-calcite may be significantly lower than those proposed.

  6. Comparison of clumped isotope signatures of dolomite cements to fluid inclusion thermometry in the temperature range of 74-180 °C

    NASA Astrophysics Data System (ADS)

    Came, R. E.; Azmy, K.; Tripati, A. K.

    2015-12-01

    Widespread application of the novel clumped isotope paleothermometer (Δ47) using carbonate samples from shallow crustal settings has been hindered by a lack of knowledge about clumped isotope systematics in carbonate minerals forming at temperatures greater than 50ºC. Furthermore, the utility of the Δ47 proxy in the mineral dolomite is limited because calibration data for dolomites that formed at any temperature are lacking. Consequently, applications involving diagenetic temperatures have required extrapolations beyond the range of most Δ47-temperature calibrations. Here we compare Δ47 values in dolomite cements to temperatures independently determined using fluid-inclusion microthermometry, and compare this rock-based "calibration" to previously published laboratory-derived calibrations for synthetic carbonates. This combination of approaches yields results that are consistent with the shallow calibration slope that has been reported from some laboratory experiments.

  7. Dialogs by Yuri V. Dublyansky regarding ``Fluid inclusion studies of calcite veins from Yucca Mountain, Nevada, tuffs: Environment of formation``. Special report number 15, Contract number 94/96.0003

    SciTech Connect

    1994-07-01

    This report is a review of a paper published in the 5th Annual International Conference on High Level Radioactive Wastes. The paper dealt with fluid inclusion studies of calcite veins from Yucca Mountain. This paper is included with this report. The author of this report analyzes the paper`s theory of the origin of these calcite deposits as dissolution and precipitation of carbonate materials from simple rainwater infiltration. The author reviews some of the methods utilized in the original research and the problems with thermometry of fluid inclusions in calcite. The author also expresses concerns over other laboratory procedures utilized to calculate various compositional values.

  8. Geology, Ore-microscopy and Fluid inclusion study on Auriferous Quartz Veins at the Gidami Gold Mine, Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Abd El Monsef, Mohamed; Salem, Ibrahim; Slobodnik, Marek

    2013-04-01

    The gold deposits are represented by auriferous quartz veins and aplitic dykes that are cutting through granitic rocks. The main lode of gold is confined to two principal veins occupying fracture zones and fissures. The main auriferous vein is striking mainly NNW-SSE with dipping 85° NE, it extends up to 450 m with an average thickness 120 cm. The second vein is striking NW-SE and dipping 60° E, it extends for 150 m with an average thickness 35 cm. The gold bearing veins are made up of fine grained quartz that is always massive, milky-white with reddish or greenish tint. They commonly include vugs, some of them are occasionally filled with iron oxides, carbonate and clay minerals. Sometimes the quartz veins enclose remnants of altered wall rock materials as an indication for the metamorphic or syntectonic nature of the veins. Brecciation, comb layering, swelling and nodules manganese dendrites are usually detected. The microscopic examination for thin and polished sections of auriferous quartz veins revealed that quartz and calcite are the predominant minerals commonly associated with accessory minerals (fluorite, apatite, zircon, muscovite and sericite). Ore mineral assemblage is found as disseminated sulfide minerals (pyrite, sphalerite, chalcopyrite, molybdenite, pyrrhotite covellite, galena and pentlandite). Ilmenite and goethite are the main iron oxide mineral phases. Gold most commonly occurs as small inclusions within pyrite or goethite. Gold also occurs as tiny grains scattered within quartz vein (in close proximity to the sulfides) or as disseminated grains in the altered wall rocks. Hydrothermal alteration includes silicification, kaolinitization, sericitisation, carbonatisation confined to a delicate set of veins. Petrography and microthermometry of fluid inclusions revealed that the majority of inclusions are of primary/pseudosecondary nature that occur in clusters and along growth zones or along intra-granular planar trails (pseudosecondary

  9. Geochronology and fluid inclusion study of the Yinjiagou porphyry-skarn Mo-Cu-pyrite deposit in the East Qinling orogenic belt, China

    NASA Astrophysics Data System (ADS)

    Wu, Guang; Chen, Yuchuan; Li, Zongyan; Liu, Jun; Yang, Xinsheng; Qiao, Cuijie

    2014-01-01

    The Yinjiagou Mo-Cu-pyrite deposit of Henan Province is located in the Huaxiong block on the southern margin of the North China craton. It differs from other Mo deposits in the East Qingling area because of its large pyrite resource and complex associated elements. The deposit's mineralization process can be divided into skarn, sulfide, and supergene episodes with five stages, marking formation of magnetite in the skarn episode, quartz-molybdenite, quartz-calcite-pyrite-chalcopyrite-bornite-sphalerite, and calcite-galena-sphalerite in the sulfide episode, and chalcedony-limonite in the supergene episode. Re-Os and 40Ar-39Ar dating indicates that both the skarn-type and porphyry-type orebodies of the Yinjiagou deposit formed approximately 143 Ma ago during the Early Cretaceous. Four types of fluid inclusions (FIs) have been distinguished in quartz phenocryst, various quartz veins, and calcite vein. Based on petrographic observations and microthermometric criteria the FIs include liquid-rich, gas-rich, H2O-CO2, and daughter mineral-bearing inclusions. The homogenization temperature of FIs in quartz phenocrysts of K-feldspar granite porphyry ranges from 341 °C to >550 °C, and the salinity is 0.4-44.0 wt% NaCl eqv. The homogenization temperature of FIs in quartz-molybdenite veins is 382-416 °C, and the salinity is 3.6-40.8 wt% NaCl eqv. The homogenization temperature of FIs in quartz-calcite-pyrite-chalcopyrite-bornite-sphalerite ranges from 318 °C to 436 °C, and the salinity is 5.6-42.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz-molybdenite stockworks is in a range of 321-411 °C, and the salinity is 6.3-16.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz-sericite-pyrite is in a range of 326-419 °C, and the salinity is 4.7-49.4 wt% NaCl eqv. The ore-forming fluids of the Yinjiagou deposit are mainly high-temperature, high-salinity fluids, generally with affinities to an H2O-NaCl-KCl ± CO2 system. The δ18OH2O values of ore

  10. Illitization and paleothermal regimes in the Middle Ordovician St. Peter Sandstone, Central Michigan Basin: K-Ar, Oxygen Isotope, and fluid inclusion data

    SciTech Connect

    Girard, J.P.; Barnes, D.A.

    1995-01-01

    Hydrocarbon reservoirs occur in the Middle Ordovician St. Peter Sandstone in the central Michigan basin at depths of 1.5-3.5 km and are diagenetically altered. Latest diagenetic cements include saddle dolomite, pervasive microcrystalline illite and chlorite, and quartz. A K-Ar and {sup 18}O/{sup 16}O study of the fine-grained authigenic illite in 25 samples from 16 wells covering a large area within the basin yields K-Ar ages ranging from 367 to 322 Ma and {delta}{sup 18}O values between 12.7 and 16.9% SMOW. The {delta}{sup 18}O values of diagenetic quartz overgrowths range from 15.2 to 18.9%. Fluid inclusion temperatures in the quartz cement range from 70 to 170{degrees}C, reflecting multiple generations of diagenetic quartz and/or precipitation over most of the diagenetic history. Reequilibrated fluid inclusions in the saddle dolomite cement yield temperatures ranging from 90 to 150{degrees}C. A regionally significant episode of illitization occurred during the Late Devonian-Mississipian. Temperatures of illite formation are indirectly estimated to be in the range of 125-170{degrees}C and most paleodepths of illitization are between 2.8 and 3.2 km. These results imply that (1) illite formed from {sup 18}O-rich fluids, and (2) elevated geothermal gradients, i.e., greater than 34% C/km, existed in the Michigan basin in the late Paleozoic. The K-Ar ages and the {delta}{sup 18}O values are not correlated to present depths of the samples or paleodepths of illitization. Illites with young ages and low {delta}{sup 18}O values tend to be geographically distributed along the north-south branch of the buried Precambrian rift. The {delta}{sup 18}O values of the diagenetic quartz follow a similar trend. The spread of illite K-Ar ages and {delta}{sup 19}O values, and their geographic distribution, are best explained as reflecting abnormally high thermal regimes in the part of the basin located above the presumably highly fractured basement along the rift.

  11. Mineralogical, geochemical, fluid inclusion and isotope study of Hohentauern/Sunk sparry magnesite deposit (Eastern Alps/Austria): implications for a metasomatic genetic model

    NASA Astrophysics Data System (ADS)

    Azim Zadeh, Amir M.; Ebner, Fritz; Jiang, Shao-Yong

    2015-10-01

    The magnesite deposit of Hohentauern/Sunk, hosted in Viseán carbonate rocks, is one of the best-exposed examples of "Veitsch type" sparry magnesite deposits, which are located in the Veitsch nappe of the Austroalpine Greywacke zone (Eastern Alps/Austria). The sparry magnesite is stratiform and stratabound within the Viseán Steilbachgraben Formation and displays distinct metasomatic features and textures. The sparry magnesite of the Hohentauern/Sunk deposit is characterized by pinolites, rosettes and banded (zebra) textures. Due to microinclusions of dolomite and redolomitzation, the CaO/MgO of magnesite is elevated. Concentrations of selected major and trace elements (Fe-Mn, Sr-Ba, Cr-Ni) in sparry magnesite indicate formation in a marine/evaporitic environment and by Mg2+-metasomatism. The REE patterns of magnesite are characterized by low LREE/HREE, depletion of LREE and a negative Ce anomaly. The δ18O (9.59 to 12.32 ‰ SMOW) and δ13C (-2.23 to -0.02 ‰ PDB) values of magnesite overlap with those published for magnesite formed by metasomatic replacement of dolomite. Fluid inclusions in the sparry magnesite indicate a high salinity (22.4 mass% NaCl equivalent) of the Mg-rich fluid; it is of marine/evaporitic origin. All geological, petrographical and geochemical features support a diagenetic dolomitization of the carbonate host rocks followed by magnesite formation via metasomatic replacement and redolomitization. Sm-Nd geochronology indicates a Late Carboniferous to Early Permian age for magnesite formation triggered by intraformational circulation of fluids derived from buried Carboniferous evaporites.

  12. The sources of volatile and fluid-mobile elements in the Sunda arc: A melt inclusion study from Kawah Ijen and Tambora volcanoes, Indonesia

    NASA Astrophysics Data System (ADS)

    Vigouroux, Nathalie; Wallace, Paul J.; Williams-Jones, Glyn; Kelley, Katherine; Kent, Adam J. R.; Williams-Jones, Anthony E.

    2012-09-01

    Subduction zone recycling of volatiles (H2O, Cl, S, F) is controlled by the nature of subducted materials and the temperature-pressure profile of the downgoing slab. We investigate the variability in volatile and fluid-mobile trace element enrichment in the Sunda arc using melt inclusion data from Kawah Ijen and Tambora volcanoes, together with published data from Galunggung, Indonesia. Combining our results with data from other arcs, we investigate the mobility of these elements during slab dehydration and melting. We observe correlations between Sr, H2O and Cl contents, indicating coupling of these elements during subduction zone recycling. Sulfur is more variable, and fluorine contents generally remain at background mantle values, suggesting decoupling of these elements from H2O and Cl. Partial melting and dehydration models constrain the source of Sr and the volatiles and suggest that the altered oceanic crust (AOC) is the main source of the hydrous component that fluxes into the mantle wedge, in agreement with thermo-mechanical models. Sediment melt remains an important component for other elements such as Ba, Pb, Th and the LREE. The Indonesian volcanoes have variable concentrations of volatile and fluid-mobile elements, with Kawah Ijen recording higher AOC-derived fluid fluxes (Sr/Nd and H2O/Nd) compared to Galunggung and Tambora. Kawah Ijen has H2O/Ce ratios that are comparable to some of the most volatile-rich magmas from other cold slab subduction zones worldwide, and the highest yet measured in the Sunda arc.

  13. Carbonate Mineral Assemblages as Inclusions in Yakutian Diamonds: TEM Verifications

    NASA Astrophysics Data System (ADS)

    Logvinova, A. M.; Wirth, R.; Sobolev, N. V.; Taylor, L. A.

    2014-12-01

    Carbonate mineral inclusions are quite rare in diamonds from the upper mantle, but are evidence for a carbonate abundance in the mantle. It is believed that such carbonatitic inclusions originated from high-density fluids (HDFs) that were enclosed in diamond during its growth. Using TEM and EPMA, several kinds of carbonate inclusions have been identified in Yakutian diamonds : aragonite, dolomite, magnesite, Ba-, Sr-, and Fe-rich carbonates. Most of them are represented by multi-phase inclusions of various chemically distinct carbonates, rich in Ca, Mg, and K and associated with minor amounts of silicate, oxide, saline, and volatile phases. Volatiles, leaving some porosity, played a significant role in the diamond growth. A single crystal of aragonite (60μm) is herein reported for the first time. This inclusion is located in the center of a diamond from the Komsomolskaya pipe. Careful CL imaging reveals the total absence of cracks around the aragonite inclusion - i.e., closed system. This inclusion has been identified by X-ray diffraction and microprobe analysis. At temperatures above 1000 0C, aragonite is only stable at high pressures of 5-6 GPa. Inside this aragonite, we observed nanocrystalline inclusions of titanite, Ni-rich sulfide, magnetite, water-bearing Mg-silicate, and fluid bubbles. Dolomite is common in carbonate multi-phase inclusions in diamonds from the Internatsionalnaya, Yubileinaya, and Udachnaya kimberlite pipes. Alluvial diamonds of the northeastern Siberian Platform are divided into two groups based on the composition of HDFs: 1) Mg-rich multi-phase inclusions (60% magnesite + dolomite + Fe-spinel + Ti-silicate + fluid bubbles); and 2) Ca-rich multi-phase inclusions (Ca,Ba-, Ca,Sr-, Ca,Fe-carbonates + Ti-silicate + Ba-apatite + fluid bubbles). High-density fluids also contain K. Volatiles in the fluid bubbles are represented by water, Cl, F, S, CO2, CH4, and heavy hydrocarbons. Origin of the second group of HDFs may be related to the non

  14. Microscale depletion of high abundance proteins in human biofluids using IgY14 immunoaffinity resin: Analysis of human plasma and cerebrospinal fluid

    DOE PAGES

    Hyung, Seok Won; Piehowski, Paul D.; Moore, Ronald J.; Orton, Daniel J.; Schepmoes, Athena A.; Clauss, Therese R.; Chu, Rosalie K.; Fillmore, Thomas L.; Brewer, Heather M.; Liu, Tao; et al

    2014-09-06

    Removal of highly abundant proteins in plasma is often carried out using immunoaffinity depletion to extend the dynamic range of measurements to lower abundance species. While commercial depletion columns are available for this purpose, they generally are not applicable to limited sample quantities (<20 µL) due to low yields stemming from losses caused by nonspecific binding to the column matrix. Additionally, the cost of the depletion media can be prohibitive for larger scale studies. Modern LC-MS instrumentation provides the sensitivity necessary to scale-down depletion methods with minimal sacrifice to proteome coverage, which makes smaller volume depletion columns desirable for maximizingmore » sample recovery when samples are limited, as well as for reducing the expense of large scale studies. We characterized the performance of a 346 µL column volume micro-scale depletion system, using four different flow rates to determine the most effective depletion conditions for ~6 μL injections of human plasma proteins and then evaluated depletion reproducibility at the optimum flow rate condition. Depletion of plasma using a commercial 10 mL depletion column served as the control. Results showed depletion efficiency of the micro-scale column increased as flow rate decreased, and that our micro-depletion was reproducible. We found, in an initial application, a 600 µL sample of human cerebral spinal fluid (CSF) pooled from multiple sclerosis patients was depleted and then analyzed using reversed phase liquid chromatography-mass spectrometry to demonstrate the utility of the system for this important biofluid where sample quantities are more commonly limited.« less

  15. Microscale depletion of high abundance proteins in human biofluids using IgY14 immunoaffinity resin: Analysis of human plasma and cerebrospinal fluid

    SciTech Connect

    Hyung, Seok Won; Piehowski, Paul D.; Moore, Ronald J.; Orton, Daniel J.; Schepmoes, Athena A.; Clauss, Therese R.; Chu, Rosalie K.; Fillmore, Thomas L.; Brewer, Heather M.; Liu, Tao; Zhao, Rui; Smith, Richard D.

    2014-09-06

    Removal of highly abundant proteins in plasma is often carried out using immunoaffinity depletion to extend the dynamic range of measurements to lower abundance species. While commercial depletion columns are available for this purpose, they generally are not applicable to limited sample quantities (<20 µL) due to low yields stemming from losses caused by nonspecific binding to the column matrix. Additionally, the cost of the depletion media can be prohibitive for larger scale studies. Modern LC-MS instrumentation provides the sensitivity necessary to scale-down depletion methods with minimal sacrifice to proteome coverage, which makes smaller volume depletion columns desirable for maximizing sample recovery when samples are limited, as well as for reducing the expense of large scale studies. We characterized the performance of a 346 µL column volume micro-scale depletion system, using four different flow rates to determine the most effective depletion conditions for ~6 μL injections of human plasma proteins and then evaluated depletion reproducibility at the optimum flow rate condition. Depletion of plasma using a commercial 10 mL depletion column served as the control. Results showed depletion efficiency of the micro-scale column increased as flow rate decreased, and that our micro-depletion was reproducible. We found, in an initial application, a 600 µL sample of human cerebral spinal fluid (CSF) pooled from multiple sclerosis patients was depleted and then analyzed using reversed phase liquid chromatography-mass spectrometry to demonstrate the utility of the system for this important biofluid where sample quantities are more commonly limited.

  16. Hydrocarbon migration and accumulation in the Upper Cretaceous Qingshankou Formation, Changling Sag, southern Songliao Basin: Insights from integrated analyses of fluid inclusion, oil source correlation and basin modelling

    NASA Astrophysics Data System (ADS)

    Dong, Tian; He, Sheng; Wang, Dexi; Hou, Yuguang

    2014-08-01

    The Upper Cretaceous Qingshankou Formation acts as both the source and reservoir sequence in the Changling Sag, situated in the southern end of the Songliao Basin, northeast China. An integrated approach involving determination of hydrocarbon charging history, oil source correlation and hydrocarbon generation dynamic modeling was used to investigate hydrocarbon migration processes and further predict the favorable targets of hydrocarbon accumulations in the Qingshankou Formation. The hydrocarbon generation and charge history was investigated using fluid inclusion analysis, in combination with stratigraphic burial and thermal modeling. The source rocks began to generate hydrocarbons at around 82 Ma and the hydrocarbon charge event occurred from approximately 78 Ma to the end of Cretaceous (65.5 Ma) when a large tectonic uplift took place. Correlation of stable carbon isotopes of oils and extracts of source rocks indicates that oil was generated mainly from the first member of Qingshankou Formation (K2qn1), suggesting that hydrocarbon may have migrated vertically. Three dimensional (3D) petroleum system modeling was used to evaluate the processes of secondary hydrocarbon migration in the Qingshankou Formation since the latest Cretaceous. During the Late Cretaceous, hydrocarbon, mainly originated from the Qianan depression, migrated laterally to adjacent structural highs. Subsequent tectonic inversion, defined as the late Yanshan Orogeny, significantly changed hydrocarbon migration patterns, probably causing redistribution of primary hydrocarbon reservoirs. In the Tertiary, the Heidimiao depression was buried much deeper than the Qianan depression and became the main source kitchen. Hydrocarbon migration was primarily controlled by fluid potential and generally migrated from relatively high potential areas to low potential areas. Structural highs and lithologic transitions are potential traps for current oil and gas exploration. Finally, several preferred hydrocarbon

  17. The Inclusive Classroom: How Inclusive Is Inclusion?

    ERIC Educational Resources Information Center

    Reid, Claudette M.

    2010-01-01

    This paper presents the position that inclusion is limited; inclusion does not go far enough. The inclusive classroom has been assessed to be of benefit both to the teacher and student. There are, however, limits set on inclusion. In most classrooms only children with learning disability are included omitting those with severe disabilities,…

  18. Petrographic, REE, fluid inclusion and stable isotope study of magnesite from the Upper Triassic Burano Evaporites (Secchia Valley, northern Apennines): contributions from sedimentary, hydrothermal and metasomatic sources

    NASA Astrophysics Data System (ADS)

    Lugli, Stefano; Morteani, Giulio; Blamart, Dominique

    2002-06-01

    Sparry and microcrystalline magnesite are minor constituents of the Upper Triassic Burano Evaporite Formation of the northern Apennines in Italy. Petrography and geochemistry of magnesite suggest three modes of formation. (1) Evaporitic precipitation of stratified microcrystalline magnesite layers associated with sulfate and carbonate rocks. Most REE are below ICP-MS detection limits. δ18O is +20.2‰ (SMOW) and δ13C is -2.6‰ (PDB). (2) Hydrothermal infill of Fe-rich (9.78 wt% FeO) lenticular sparry magnesite. This type of magnesite is characterized by very low LREE concentrations, whereas HREEs are relatively high. The fluid inclusion composition is NaCl-MgCl2-H2O, salinity is ~30 wt% NaCl equiv., and total homogenization temperatures range from 204-309 °C; δ18O is +17.5‰ and δ13C is +1‰. (3) The partial or total replacement of dolostones by lenticular sparry magnesite. LREEs are lower in magnesite compared with the partly replaced dolostones. Magnesite yields δ18O and δ13C compositions of +17.3 to +23.6‰ and +0.5 to +1.4‰, respectively, whereas the partly replaced dolostones yield δ18O and δ13C values of +25.0 to +26.2 and +1.3 to +1.9, respectively. Complete replacement of dolostones produced massive lenticular sparry magnesite rock containing ooids and axe-head anhydrite relicts; LREEs are depleted compared to unaffected dolostones; δ18O and δ13C compositions range from +16.4 to +18.4‰ and +0.4 to +0.9‰, respectively. These data and the association between fracture-filling and replacive magnesite suggests a metasomatic system induced by hydrothermal circulation of hot and saline Mg-rich fluids. These processes probably occurred in the Oligocene-Miocene, when the Burano Formation acted as main detachment horizon for the Tuscan Nappe during the greenschist facies metamorphism of the Apuane complex. Thrusting over the Apuane zone produced large scale fluid flow focused at the Tuscan Nappe front. Sources of Mg-rich fluids were metamorphic

  19. Ore geology and fluid inclusion geochemistry of the Tiemurt Pb-Zn-Cu deposit, Altay, Xinjiang, China: A case study of orogenic-type Pb-Zn systems

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Zheng, Yi; Chen, YanJing

    2012-04-01

    The Tiemurt Pb-Zn-Cu deposit is hosted in a Devonian volcanic-sedimentary basin of the Altay orogenic belt, and is thus interpreted to have formed by sea-floor hydrothermal exhalation in previous studies. Our investigation discovered that the deposit is not stratiform or stratabound, but structure-controlled instead. The hydrothermal ore-forming process can be divided into the early, middle and late stage, represented by pyrite-quartz, polymetallic sulfide-quartz and carbonate-quartz veinlets, respectively. The early-stage veins and contained minerals are structurally deformed and brecciated, suggesting a compressional or transpressional tectonic regime. The middle-stage veinlets intrude and infill the fissures of the early-stage assemblages, and show no deformation, suggesting a tensional shear setting. The late-stage veinlets mostly infill open-space fissures that crosscut veins and replacements formed in the earlier stages. Four types of fluid inclusions (FIs), including aqueous (type W), carbonic-aqueous (type C), pure carbonic (type PC) and solid-bearing (type S), are identified at the Tiemurt deposit. The early-stage minerals contain the C- and W-type primary FIs that are totally homogenized at temperatures of 330-390 °C with low salinities of 0.8-11.9 wt.% NaCl eqv.; whilst the late-stage quartz or calcite contains only the W-type FIs with homogenization temperatures of 118-205 °C, and salinities of 1.4-3.4 wt.% NaCl eqv. This indicates that the ore fluid system evolved from CO2-rich, probably metamorphic to CO2-poor, meteoric fluids; and that a significant CO2-escape must have occurred. All the four types of FIs can be only observed in the middle-stage minerals, and even in a microscopic domain of a crystal, representing an association trapped from a boiling fluid system. These FIs homogenize at temperatures ranging from 270 to 330 °C, with two salinity clusters of 1.9-14.5 and 37.4-42.4 wt.% NaCl eqv., respectively. This implies that metal precipitation

  20. VOC and VOX in fluid inclusions of quartz: New chemical insights into hydrothermal vein mineralization by GC-MS and GC-IRMS measurements

    NASA Astrophysics Data System (ADS)

    Sattler, Tobias; Kirnbauer, Thomas; Keppler, Frank; Greule, Markus; Fischer, Jan; Spiekermann, Patrik; Schreiber, Ulrich; Mulder, Ines; Schöler, Heinz Friedrich

    2015-04-01

    Fluid inclusions (FIs) in minerals are known to contain a variety of different liquids, gases, and solids. The fluids get trapped during mineral growth and can preserve the original mineral-forming fluid or fluids of later events. A new analytical technique developed by Mulder et al. (2013) [1] allows to measure trace gases in FIs. For the measurements, grains of 3-5 mm diameter are ground in an airtight grinding device, releasing the volatiles from FIs into the gas phase, where they can be measured by GC-MS, GC-FID and GC-IRMS. The Taunus covers the southeastern part of the thrust-and-fold-belt of the Rhenish Massif (Germany). The Variscan rock sequences comprise sedimentary and volcanic units ranging from Ordovician to Lower Carboniferous. Several types of hydrothermal mineralization can be distinguished, which are - in regard to the Variscan orogeny - pre-orogenic, orogenic, late-orogenic, post-orogenic and recent in age [2]. They include SEDEX, vein, Alpine fissure, disseminated and stockwerk mineralizations. Thus, the Taunus mineralizations enable investigations of different hydrothermal systems at different age in one region. For most of them extensive studies of stable and radiogenic isotopes exist. Quartz crystals of post-orogenic quartz veins and Pb-Zn-Cu bearing veins [3] were selected for our FI investigation. Sulphur containing compounds like COS and CS2 dominate the FIs but there are also volatile hydrocarbons (VOC) like different butenes, benzene, toluene and cyclopentene that were found very often. In some samples volatile halogenated organic carbons (VOX) like chloro- and bromomethane were found. Some FIs even contain iodomethane, chlorobenzene, vinyl chloride and -bromide. The non-fossil-fuel subsurface chemistry of VOC and VOX is not fully understood. There are a lot of unknown geogenic sources [4][5]. For a better understanding δ13C- and δ2H-values of CH4 were measured by GC-IRMS to examine if the detected organic compounds are formed biotic

  1. Melt- versus fluid-induced metasomatism in spinel to garnet wedge peridotites (Ulten Zone, Eastern Italian Alps): clues from trace element and Li abundances

    NASA Astrophysics Data System (ADS)

    Scambelluri, M.; Hermann, J.; Morten, L.; Rampone, E.

    2006-04-01

    anomalies in Cs, Ba, Pb and U and moderate enrichment in Li, indicating addition of a crustal component to the mantle rocks. Amphibole hosts most of these trace elements. Clinopyroxene displays high LILE/HFSE (Pb N /Nb N =300-600), low Ce/Pb (1.4-2.7 in garnet-facies clinopyroxene compared with 2.6-24.5 in the spinel-facies one) and variable LILE and LREE enrichments. The coupled increase of modal amphibole, Sr and Pb, together with positive Pb-Sr and Pb-U correlations, further indicate that incompatible element influx in these samples was fluid-mediated. In the garnet-facies samples, amphibole and, interestingly, olivine have similarly high Li concentrations as clinopyroxene, leading to cpx/amph D Li=0.7 and cpx/ol D Li=0.7-0.8, the latter being up to ten times lower than in the spinel-facies rocks. Due to its high modal abundance, olivine is the main host of Li in the garnet-amphibole peridotites. The observed metasomatic features provide evidence for the infiltration of an aqueous fluid in the mantle wedge above a subducting slab. This fluid most likely derived from subducted crustal rocks that underwent partial melting. Successive retrograde re-equilibration during exhumation of the garnet peridotite is accompanied by garnet and clinopyroxene breakdown and amphibole formation. This process produced minor changes, such as an increase of HREE and Li in amphibole, and an increase of Li in olivine. The general trace element signature remains essentially unchanged during retrogression and further hydration, indicating that fluids with a similar composition to the one present at the garnet-amphibole peridotite formation, were responsible for increased amphibole formation. The combined evidence from the metamorphic and metasomatic evolution indicates that the peridotites experienced first corner flow in a mantle wedge, followed by subduction and finally entrapment and exhumation within a crustal slab. During their entire history the Ulten peridotites were percolated first by

  2. Microthermometric and stable isotopic (O and H) characteristics of fluid inclusions in the porphyry related Çöpler (İliç - Erzincan) gold deposit, central eastern Turkey

    NASA Astrophysics Data System (ADS)

    Canbaz, Oktay; Gökce, Ahmet

    2014-06-01

    The Çöpler gold deposit occurs within the stockwork of quartz hosted by the Çöpler granitoid (Eosen) and by surrounding metasediments of Keban metamorphic (Late Paleozoic - Early Mesozoic) and the Munzur limestones (Late Carboniferous - Early Cretaceous). Native gold accompanied by small amounts of chalcopyrite, pyrite, magnetite, maghemite, hematite, fahlerz, marcasite, bornite, galena, sphalerite, specular hematite, goethite, lepidochrosite and bravoitic pyrite within the stockwork ore veinlets. In addition, epidote (pistazite - zoisite), garnet, scapolite, chlorite, tremolite/actinolite, muscovite and opaque minerals were determined within the veinlets occurred in skarn zones. The study of fluid inclusions in quartz veinlets showed that the hydrothermal fluids contain CaCl2, MgCl2 and NaCl and the salinities of the two phases (L+V) inclusions range from 1.7 to 20.6% NaCl equivalent. Salinity values up to 44% were determined within the halite bearing three phases inclusions. Their homogenization temperature values have a wide range from 145.0 to 380.0°C, indicative of catathermal/hypothermal to epithermal conditions. The δ 18O and δD values of the fluid inclusion waters from the Çöpler granitoid correspond to those assigned to Primary Magmatic Water, those from the metasediments of Keban metamorphics fall outside of the Primary Magmatic and are within the Metamorphic Water field. A sample from a quartz vein within the skarn zone hosted by the Munzur limestones has a particularly low δD value. The results suggest that fluids derived from the granitoids were mixed with those derived from the metasediments of Keban metamorphics and the the Munzur limestones and resulting in quartz veinlets in these lithologies and the formation of stockwork ores. In view of the occurrence, the features described and processes envisaged for this study area may be applicable in similar settings.

  3. Very high-density carbonic fluid inclusions in sapphirine-bearing granulites from Tonagh Island in the Archean Napier Complex, East Antarctica: implications for CO2 infiltration during ultrahigh-temperature (T>1,100 °C) metamorphism

    NASA Astrophysics Data System (ADS)

    Tsunogae, Toshiaki; Santosh, M.; Osanai, Yasuhito; Owada, Masaaki; Toyoshima, Tsuyoshi; Hokada, Tomokazu

    2002-02-01

    The ultrahigh-temperature (UHT) metamorphism of the Napier Complex is characterized by the presence of dry mineral assemblages, the stability of which requires anhydrous conditions. Typically, the presence of the index mineral orthopyroxene in more than one lithology indicates that H2O activities were substantially low. In this study, we investigate a suite of UHT rocks comprising quartzo-feldspathic garnet gneiss, sapphirine granulite, garnet-orthopyroxene gneiss, and magnetite-quartz gneiss from Tonagh Island. High Al contents in orthopyroxene from sapphirine granulite, the presence of an equilibrium sapphirine-quartz assemblage, mesoperthite in quartzo-feldspathic garnet gneiss, and an inverted pigeonite-augite assemblage in magnetite-quartz gneiss indicate that the peak temperature conditions were higher than 1,000 °C. Petrology, mineral phase equilibria, and pressure-temperature computations presented in this study indicate that the Tonagh Island granulites experienced maximum P-T conditions of up to 9 kbar and 1,100 °C, which are comparable with previous P-T estimates for Tonagh and East Tonagh Islands. The textures and mineral reactions preserved by these UHT rocks are consistent with an isobaric cooling (IBC) history probably following an counterclockwise P-T path. We document the occurrence of very high-density CO2-rich fluid inclusions in the UHT rocks from Tonagh Island and characterize their nature, composition, and density from systematic petrographic and microthermometric studies. Our study shows the common presence of carbonic fluid inclusions entrapped within sapphirine, quartz, garnet and orthopyroxene. Analysed fluid inclusions in sapphirine, and some in garnet and quartz, were trapped during mineral growth at UHT conditions as 'primary' inclusions. The melting temperatures of fluids in most cases lie in the range of -56.3 to -57.2 °C, close to the triple point for pure CO2 (-56.6 °C). The only exceptions are fluid inclusions in magnetite

  4. Coupled measurements of δ18O and δD of hydration water and salinity of fluid inclusions in gypsum from the Messinian Yesares Member, Sorbas Basin (SE Spain)

    NASA Astrophysics Data System (ADS)

    Evans, Nicholas P.; Turchyn, Alexandra V.; Gázquez, Fernando; Bontognali, Tomaso R. R.; Chapman, Hazel J.; Hodell, David A.

    2015-11-01

    We studied one cycle (Cycle 6) of gypsum-marl deposition from the Messinian Yesares Member in Sorbas Basin, Spain. The objective was to reconstruct the changing environment of deposition and its relation to astronomically-forced climate change. The δ18O and δD of gypsum hydration water (CaSO4 • 2H2O) and salinity of fluid inclusions were measured in the same samples to test if they record the composition of the mother fluid from which gypsum was precipitated. Water isotopes are highly correlated with fluid inclusion salinity suggesting the hydration water has not exchanged after formation. The relatively low water isotope values and fluid inclusion salinities indicate a significant influence of meteoric water, whereas δ34S, δ18OSO4 and 87Sr/86Sr support a dominant marine origin for the gypsum deposits. The discrepancy between water and elemental isotope signatures can be reconciled if meteoric water dissolved previously deposited marine sulfates supplying calcium and sulfate ions to the basin which maintained gypsum saturation. This recycling process accounts for the marine δ34S, δ18OSO4 and 87Sr/86Sr signatures, whereas the low δ18O and δD values of gypsum hydration water and fluid inclusion salinities reflect the influence of freshwater. The cyclic deposition of gypsum and marl in the Yesares Member has previously been interpreted to reflect changing climate related to Earth's precession cycle. We demonstrate that the δ18O, δD and salinity of the parent brine increased from low values at the base of the cycle to a maximum in the massive gypsum palisade, and decreased again to lower values in the supercones at the top of the cycle. This pattern, together with changes in mineralogy (calcite-dolomite-gypsum), is consistent with a precession-driven change in climate with wettest conditions (summer insolation maxima) associated with the base of the calcium carbonate marls and driest conditions (summer insolation minima) during formation of the gypsum

  5. Paleofluid-flow circulation within a Triassic rift basin: Evidence from oil inclusions and thermal histories

    USGS Publications Warehouse

    Tseng, H.-Y.; Burruss, R.C.; Onstott, T.C.; Omar, G.

    1999-01-01

    The migration of subsurface fluid flow within continental rift basins has been increasingly recognized to significantly affect the thermal history of sediments and petroleum formation. To gain insight into these paleofluid flow effects, the thermal history of the Taylorsville basin in Virginia was reconstructed from fluid-inclusion studies, apatite fission-track data, and vitrinite reflectance data. Models of thermal history indicate that the basin was buried to the thermal maximum at 200 Ma; a cooling event followed during which the eastern side of the basin cooled earlier and faster than the western side, suggesting that there was a differential uplift and topographically driven fluid flow. This hypothesis is supported by analyses of secondary oil and aqueous inclusions trapped in calcite and quartz veins during the uplift stage. Gas chromatograms of inclusion oils exhibit variable but extensive depletion of light molecular-weight hydrocarbons. The relative abundance of n-alkanes, petrographic observations, and the geological data indicate that the alteration process on these inclusion oils was probably neither phase separation nor biodegradation, but water washing. Water:oil ratios necessary to produce the observed alteration are much greater than 10000:1. These exceedingly high ratios are consistent with the migration of inclusion oils along with fluid flow during the early stages of basin evolution. The results provide significant evidence about the role of a subsurface flow system in modifying the temperature structure of the basin and the composition of petroleum generated within the basin.

  6. Hydrothermal alteration, fluid inclusions and stable isotope systematics of the Alvo 118 iron oxide-copper-gold deposit, Carajás Mineral Province (Brazil): Implications for ore genesis

    NASA Astrophysics Data System (ADS)

    Torresi, Ignacio; Xavier, Roberto Perez; Bortholoto, Diego F. A.; Monteiro, Lena V. S.

    2012-03-01

    The Alvo 118 iron oxide-copper-gold (IOCG) deposit (170 Mt at 1.0 wt.% Cu, 0.3 g/t Au) lies in the southern sector of the Itacaúnas Shear Belt, Carajás Mineral Province, along a WNW-ESE-striking, 60-km-long shear zone, close to the contact of the ~2.76-Ga metavolcano-sedimentary Itacaiúnas Supergroup and the basement (~3.0 Ga Xingu Complex). The Alvo 118 deposit is hosted by mafic and felsic metavolcanic rocks and crosscutting granitoid and gabbro intrusions that have been subjected to the following hydrothermal alteration sequence towards the ore zones: (1) poorly developed sodic alteration (albite and scapolite); (2) potassic alteration (biotite or K-feldspar) accompanied by magnetite formation and silicification; (3) widespread, pervasive chlorite alteration spatially associated with quartz-carbonate-sulphide infill ore breccia and vein stockworks; and (4) local post-ore quartz-sericite alteration. The ore assemblage is dominated by chalcopyrite (~60%), bornite (~10%), hematite (~20%), magnetite (10%) and subordinate chalcocite, native gold, Au-Ag tellurides, galena, cassiterite, F-rich apatite, xenotime, monazite, britholite-(Y) and a gadolinite-group mineral. Fluid inclusion studies in quartz point to a fluid regime composed of two distinct fluid types that may have probably coexisted within the timeframe of the Cu-Au mineralizing episode: a hot (>200°C) saline (32.8‰ to 40.6 wt.% NaCl eq.) solution, represented by salt-bearing aqueous inclusions, and a lower temperature (<200°C), low to intermediate salinity (<15 wt.% NaCl eq.) aqueous fluid defined by two-phase (LH2O + VH2O) fluid inclusions. This trend is very similar to those defined for other IOCG systems of the Carajás Mineral Province. δ 18OH2O values in equilibrium with calcite (-1.0‰ to 7.5‰ at 277°C to 344°C) overlap the lower range for primary magmatic waters, but the more 18O-depleted values also point to the involvement of externally derived fluids, possibly of meteoric origin

  7. Mineralogical, fluid inclusion, and stable isotope constraints on mechanisms of ore deposition at the Samgwang mine (Republic of Korea)—a mesothermal, vein-hosted gold-silver deposit

    NASA Astrophysics Data System (ADS)

    Yoo, Bong Chul; Lee, Hyun Koo; White, Noel C.

    2010-02-01

    The Samgwang mine is located in the Cheongyang gold district (Cheonan Metallogenic Province) of the Republic of Korea. It consists of eight massive, gold-bearing quartz veins that filled NE- and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. Their mineralogy and paragenesis allow two separate vein-forming episodes to be recognized, temporally separated by a major faulting event. The ore minerals occur in quartz and calcite of stage I, associated with fracturing and healing of veins. Hydrothermal wall-rock alteration minerals of stage I include Fe-rich chlorite (Fe/(Fe+Mg) ratios 0.74-0.81), muscovite, illite, K-feldspar, and minor arsenopyrite, pyrite, and carbonates. Sulfide minerals deposited along with electrum during this stage include arsenopyrite, pyrite, pyrrhotite, sphalerite, marcasite, chalcopyrite, galena, argentite, pyrargyrite, and argentian tetrahedrite. Only calcite was deposited during stage II. Fluid inclusions in quartz contain three main types of C-O-H fluids: CO2-rich, CO2-H2O, and aqueous inclusions. Quartz veins related to early sulfides in stage I were deposited from H2O-NaCl-CO2 fluids (1,500-5,000 bar, average 3,200) with T htotal values of 200°C to 383°C and salinities less than about 7 wt.% NaCl equiv. Late sulfide deposition was related to H2O-NaCl fluids (140-1,300 bar, average 700) with T htotal values of 110°C to 385°C and salinities less than about 11 wt.% NaCl equiv. These fluids either evolved through immiscibility of H2O-NaCl-CO2 fluids as a result of a decrease in fluid pressure, or through mixing with deeply circulated meteoric waters as a result of uplift or unloading during mineralization, or both. Measured and calculated sulfur isotope compositions (δ34SH2S = 1.5 to 4.8‰) of hydrothermal fluids from the stage I quartz veins indicate that ore sulfur was derived mainly from a magmatic source. The calculated and measured oxygen and hydrogen isotope compositions (δ18OH2O

  8. Mechanisms of submicron inclusion re-equilibration during host mineral deformation

    NASA Astrophysics Data System (ADS)

    Griffiths, Thomas; Habler, Gerlinde; Abart, Rainer; Rhede, Dieter; Wirth, Richard

    2014-05-01

    data, and no subgrain boundaries. Secondly, garnet lattice rotation of up to 10° around rational garnet crystal axes is observed in connection with some already coarsened inclusions. Strain concentrations are widespread in some trails, but rare in others. A TEM foil transecting a garnet domain with concentrated lattice rotation in association with inclusions reveals well developed polygonal subgrain walls with few free dislocations. Where dislocation density is greatest, almost no <100nm inclusions are observed, whereas these are more abundant in unstrained garnet domains despite the foil being located entirely within the optically visible bleaching zone. Chlorite inclusions and formation of etch pits at dislocations at the garnet-chlorite interface demonstrate the presence of fluid along subgrain boundaries during this second bleaching process. In summary, brittle deformation in these garnets led to enhanced transport and inclusion re-equilibration by coarsening, forming inclusion trails. The precise mechanism allowing enhanced transport is still to be determined and may have involved fluid supply with or without pipe diffusion along introduced dislocations. Later ductile deformation via dislocations, concentrated at already coarsened inclusions and enhanced by fluid availability, further affected the nanoinclusion population. The inclusion trail microstructure records complex small-scale interaction between deformation and reaction, shedding light on the mechanisms by which re-equilibration and strain localisation can influence each other in deforming host-inclusion systems. Bestmann et al. (2008) Journal of Structural Geology 30: 777-790

  9. Inclusive Schools.

    ERIC Educational Resources Information Center

    Schrag, Judy; Burnette, Jane

    1994-01-01

    This review of five recent (1992 and 1993) books and journal articles is intended to illuminate characteristics of inclusive schools. The review defines inclusion as more than merely regular class placement for students with disabilities, to include a philosophy which celebrates diversity and the provision of a continuum of educational options.…

  10. Origin of the Zálesí U-Ni-Co-As-Ag/Bi deposit, Bohemian Massif, Czech Republic: fluid inclusion and stable isotope constraints

    NASA Astrophysics Data System (ADS)

    Dolníček, Zdeněk; Fojt, Bohuslav; Prochaska, Walter; Kučera, Jan; Sulovský, Petr

    2009-01-01

    The Zálesí vein-type deposit is hosted by Early Paleozoic high-grade metamorphic rocks on the northern margin of the Bohemian Massif. The mineralization is composed of three main stages: uraninite, arsenide, and sulfide. The mineral assemblages formed at low temperatures (~80 to 130°C, locally even lower) and low pressures (<100 bars). The salinity of the aqueous hydrothermal fluids (0 to 27 wt.% salts) and their chemical composition vary significantly. Early fluids of the oldest uraninite stage contain a small admixture of a clathrate-forming gas, possibly CO2. Salinity correlates with oxygen isotope signature of the fluid and suggests mixing of brines [ δ 18O around +2‰ relative to standard mean ocean water (SMOW)] with meteoric waters ( δ 18O around -4‰ SMOW). The fluid is characterized by highly variable halogen ratios (molar Br/Cl = 0.8 × 10-3 to 5.3 × 10-3; molar I/Cl = 5.7 × 10-6 to 891 × 10-6) indicating a dominantly external origin for the brines, i.e., from evaporated seawater, which mixed with iodine-enriched halite dissolution brine. The cationic composition of these fluids indicates extensive interaction of the initial brines with their country rocks, likely associated with leaching of sulfur, carbon, and metals. The brines possibly originated from Permian-Triassic evaporites in the neighboring Polish Basin, infiltrated into the basement during post-Variscan extension and were finally expelled along faults giving rise to the vein-type mineralization. Cenozoic reactivation by low-salinity, low- δ 18O (around -10‰ SMOW) fluids of mainly meteoric origin resulted in partial replacement of primary uraninite by coffinite-like mineral aggregates.

  11. The evolution of calcite-bearing kimberlites by melt-rock reaction: evidence from polymineralic inclusions within clinopyroxene and garnet megacrysts from Lac de Gras kimberlites, Canada

    NASA Astrophysics Data System (ADS)

    Bussweiler, Y.; Stone, R. S.; Pearson, D. G.; Luth, R. W.; Stachel, T.; Kjarsgaard, B. A.; Menzies, A.

    2016-07-01

    Megacrystic (>1 cm) clinopyroxene (Cr-diopside) and garnet (Cr-pyrope) xenocrysts within kimberlites from Lac de Gras (Northwest Territories, Canada) contain fully crystallized melt inclusions. These `polymineralic inclusions' have previously been interpreted to form by necking down of melts at mantle depths. We present a detailed petrographical and geochemical investigation of polymineralic inclusions and their host crystals to better understand how they form and what they reveal about the evolution of kimberlite melt. Genetically, the megacrysts are mantle xenocrysts with peridotitic chemical signatures indicating an origin within the lithospheric mantle (for the Cr-diopsides studied here ~4.6 GPa, 1015 °C). Textural evidence for disequilibrium between the host crystals and their polymineralic inclusions (spongy rims in Cr-diopside, kelyphite in Cr-pyrope) is consistent with measured Sr isotopic disequilibrium. The preservation of disequilibrium establishes a temporal link to kimberlite eruption. In Cr-diopsides, polymineralic inclusions contain phlogopite, olivine, chromite, serpentine, and calcite. Abundant fluid inclusion trails surround the inclusions. In Cr-pyropes, the inclusions additionally contain Al-spinel, clinopyroxene, and dolomite. The major and trace element compositions of the inclusion phases are generally consistent with the early stages of kimberlite differentiation trends. Extensive chemical exchange between the host phases and the inclusions is indicated by enrichment of the inclusions in major components of the host crystals, such as Cr2O3 and Al2O3. This chemical evidence, along with phase equilibria constraints, supports the proposal that the inclusions within Cr-diopside record the decarbonation reaction: dolomitic melt + diopside → forsterite + calcite + CO2, yielding the observed inclusion mineralogy and producing associated (CO2-rich) fluid inclusions. Our study of polymineralic inclusions in megacrysts provides clear mineralogical

  12. Garnets in porphyry-skarn systems: A LA-ICP-MS, fluid inclusion, and stable isotope study of garnets from the Hongniu-Hongshan copper deposit, Zhongdian area, NW Yunnan Province, China

    NASA Astrophysics Data System (ADS)

    Peng, Hui-juan; Zhang, Chang-qing; Mao, Jing-wen; Santosh, M.; Zhou, Yun-man; Hou, Lin

    2015-05-01

    The Late Cretaceous Hongniu-Hongshan porphyry-skarn copper deposit is located in the Zhongdian area of northwestern Yunnan Province, China. Garnets from the deposit have compositions that range from Adr14Grs86 to almost pure andradite (Adr98Grs2) and display two different styles of zoning. The garnets are predominantly of magmatic-hydrothermal origin, as is evidenced by their 18Ofluid (5.4-6.9‰) and low Dfluid (-142‰ to -100‰) values, both of which likely result from late-stage magmatic open-system degassing. Three generations of garnet have been identified in this deposit: (1) Al-rich garnets (Grt I; Adr22-57Grs78-43) are anisotropic, have sector dodecahedral twinning, are slightly enriched in light rare earth elements (LREEs) compared with the heavy rare earth elements (HREEs), have negative or negligible Eu anomalies, and contain high concentrations of F. Fluid inclusions within these Al-rich garnets generally have salinities of 12-39 wt.% NaCl eq. and have liquid-vapor homogenization temperatures (Th) of 272-331 °C. The Grt I are most likely associated with low- to medium-salinity fluids that were generated by the contraction of an ascending vapor phase and that formed during diffusive metasomatism caused by pore fluids equilibrating with the host rocks at low W/R (water/rock) ratios. These garnets formed as a result of the high F activity of the system, which increased the solubility of Al within the magmato-hydrothermal fluids in the system. (2) Fe-rich garnets (Adr75-98Grs25-2) have trapezohedral faces, and are both anisotropic with oscillatory zoning and isotropic. These second-generation Fe-rich garnets (Grt II) have high ΣREE concentrations, are LREE-enriched and HREE-depleted, and generally have positive but variable Eu anomalies. All of the Fe-rich garnets contain high-salinity fluid inclusions with multiple daughter minerals with salinities of 33-80 wt.% NaCl eq. Some of them show higher temperatures of halite dissolution (465-591 °C) than

  13. Evidence for Oxygen-Isotope Exchange in Chondrules and Refractory Inclusions During Fluid-Rock Interaction on the CV Chondrite Parent Body

    NASA Astrophysics Data System (ADS)

    Krot, A. N.; Nagashima, K.

    2016-08-01

    Plagioclase in chondrules, CAIs and AOAs from the carbonaceous chondrite Kaba (CV3.1) experienced oxygen-isotope exchange with a metasomatic fluid responsible for the formation of magnetite, fayalite and Ca,Fe-rich silicates on the CV parent body.

  14. Seasonal abundance and spatio-temporal distribution of dominant xylem fluid-feeding hemiptera in vineyards of central Texas and surrounding habitats.

    PubMed

    Lauzière, Isabelle; Sheather, Simon; Mitchell, Forrest

    2008-08-01

    A survey of xylem fluid-feeding insects (Hemiptera) exhibiting potential for transmission of Xylella fastidiosa, the bacterium causing Pierce's disease of grapevine, was conducted from 2004 to 2006 in the Hill Country grape growing region of central Texas. Nineteen insect species were collected from yellow sticky traps. Among these, two leafhoppers and one spittlebug comprised 94.57% of the xylem specialists caught in this region. Homalodisca vitripennis (Germar), Graphocephala versuta (Say), and Clastoptera xanthocephala Germar trap catches varied significantly over time, with greatest counts usually recorded between May or June and August and among localities. A comparison of insect counts from traps placed inside and outside vineyards indicated that G. versuta is always more likely captured on the vegetation adjacent to the vineyard. C. xanthocephala was caught inside the vineyard during the summer. Between October and December, the natural habitat offers more suitable host plants, and insects were absent from the vineyards after the first freezes. H. vitripennis was caught in higher numbers inside the vineyards throughout the grape vegetative season. However, insects were also caught in the habitat near the affected crop throughout the year, and residual populations overwintering near vineyards were also recorded. This study shed new light on the fauna of xylem fluid-feeding insects of Texas. These results also provide critical information to vineyard managers for timely applications of insecticides before insect feeding and vectoring to susceptible grapevines.

  15. Inclusive teaching.

    PubMed

    Billings, Diane M

    2008-07-01

    Inclusive teaching involves being responsive to the diversity represented in the classroom and assisting learners to focus on their culture, attitudes, and beliefs while learning to communicate and collaborate with each other and their patients.

  16. Saline Fluids in Subduction Channels and Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Kawamoto, T.; Hertwig, A.; Schertl, H. P.; Maresch, W. V.; Shigeno, M.; Mori, Y.; Nishiyama, T.

    2015-12-01

    Saline fluids can transport large-ion-lithophile elements and carbonate. Subduction-zone fluids contain salts with various amounts of NaCl equivalent similar to that of the present and/or Phanerozoic seawater (about 3.5 wt% NaCl). The salinity of aqueous fluids in the mantle wedge decreases from trench side to back-arc side, although available data have been limited. Such saline fluids from mantle peridotite underneath Pinatubo, a frontal volcano of the Luzon arc, contain 5.1 wt% NaCl equivalent and CO2 [Kawamoto et al., 2013 Proc Natl Acad Sci USA] and in Ichinomegeta, a rear-arc volcano of the Northeast Japan arc, contain 3.7 wt% NaCl equivalent and CO2 [Kumagai et al., Contrib Mineral Petrol 2014]. Abundances of chlorine and H2O in olivine-hosted melt inclusions also suggest that aqueous fluids to produce frontal basalts have higher salinity than rear-arc basalts in Guatemala arc [Walker et al., Contrib Mineral Petrol 2003]. In addition to these data, quartz-free jadeitites contain fluid inclusions composed of aqueous fluids with 7 wt% NaCl equivalent and quartz-bearing jadeitite with 4.6 wt% NaCl equivalent in supra-subduction zones in Southwest Japan [Mori et al., 2015, International Eclogite Conference] and quartz-bearing jadeitite and jadeite-rich rocks contain fluid inclusions composed of aqueous fluids with 4.2 wt% NaCl equivalent in Rio San Juan Complex, Dominica Republic [Kawamoto et al., 2015, Goldschmidt Conference]. Aqueous fluids generated at pressures lower than conditions for albite=jadeite+quartz occurring at 1.5 GPa, 500 °C may contain aqueous fluids with higher salinity than at higher pressures.

  17. Geochronological, stable isotopes and fluid inclusion constraints for a premetamorphic development of the intrusive-hosted Björkdal Au deposit, northern Sweden

    NASA Astrophysics Data System (ADS)

    Billström, K.; Broman, C.; Jonsson, E.; Recio, C.; Boyce, A. J.; Torssander, P.

    2009-07-01

    The Björkdal gold deposit, bound to a quartz vein system which is mainly hosted by a quartz-monzodioritic intrusion, is situated at the easternmost part of the 1.9 Ga Skellefte base metal district in the Fennoscandian shield. Three fluid stages may be distinguished, referred to as a “barren” stage, a main gold stage, and a remobilization stage, respectively. From oxygen and hydrogen isotope evidence, it is argued that fluids of different origins (magmatic and surface waters) penetrated the ore zone at the inferred stages, but regional metamorphic fluids appear essentially only to have redistributed elements. Early quartz veining took place during a pre-metamorphic stage at ca. 1.88 Ga, as evidenced by unradiogenic galena data and an Sm-Nd scheelite errorchron of 1,915 ± 32 Ma (MSWD = 0.25). Temporarily, the main ore-forming stage was closely related to the first barren stage and took place during a major uplift event close to 1.88 Ga. Although other source rocks cannot be totally ruled out, available isotope data (O, S, Sr and Pb) are seemingly consistent with the view that these elements, and by inference other ore elements, were derived from the host intrusion.

  18. Evaluation of argon ages and integrity of fluid-inclusion compositions: Stepwise noble gas heating experiments on 1.87 Ga alunite from Tapajós Province, Brazil

    USGS Publications Warehouse

    Landis, G.P.; Snee, L.W.; Juliani, Caetano

    2005-01-01

    Diffusion coefficients and activation energies for the diffusion of Ar and He, as determined using Arrhenius plots, indicate two distinct groups definable by their differences in activation energies. Argon log Do=2.45 and 15.33, with activation energies of 225 and 465 kJ mol−1, respectively; the diffusion of He in alunite is quantified with log Do=−4.33 and E=106.8 kJ mol−1. Model calculations of simplistic 1/e-folding times and diffusion distance–time curves indicate that He should remain in alunite for millions of years at ≤100°C, whereas at <200–220°C, the alunite will retain Ar almost indefinitely. The data demonstrate why alunite is suitable for Ar geochronological applications and also show that, unless the alunite is subjected to metamorphic deformation, the inclusion fluids should retain their primary compositions.

  19. CaCl[sub 2]-NaCl-H[sub 2]O fluid inclusions in the Box Vein of Lyonsdale,NY a fossil shield brine in northern, New York

    SciTech Connect

    Garside, A.R.; Darling, R.S. . Dept. of Geology)

    1993-03-01

    The Box Vein of Lyonsdale, NY is characterized by calcite-hosted, box-like cavities (equidimensional to tabular in shape) lined with comb-structured quartz. Quartz deposition was followed by late calcite, rare chalcopyrite, and solid organic matter (similar to anthraxolite associated with Herkimer quartz). The geologic setting of the vein is similar to Rossie-type veins in that it is hosted by Precambrian gneisses, but postdates Grenville metamorphism. Primary fluid inclusions in quartz (defined by growth zones) contain H[sub 2]O (vapor) + H[sub 2]O (brine) at room temperature. Upon warming from liquid nitrogen temperatures ([minus]196C), the ice and salt-hydrates gradually darkened and became granular between [minus]65C and [minus]52C, temperatures and phase behavior consistent with first melting in the CaCl[sub 2]-NaCl-H[sub 2]O system. Final ice melting temperatures average [minus]25.2C [plus minus] 1.4C (1 [sigma], N = 9). Final hydrohalite melting temperatures average [minus]13.2C [plus minus] 2.9C (1 [sigma], N = 6). Hydrohalite was distinguished from ice by its higher birefringence and lower relief. Inclusions homogenized to liquid at temperatures averaging 151C [plus minus] 7C (1 [sigma], N = 17). The microthermometric measurements were recorded by temperature cycling. Final melting temperatures of ice and hydrohalite indicate NaCl and CaCl[sub 2] contents of 17 [plus minus] 0.5 and 9 [plus minus] 1 wt. %, respectively (as modeled in the ternary CaCl[sub 2]-NaCl-H[sub 2]O system). The geologic setting, saline fluid chemistry, and relatively low temperature ([approximately]150C) of the Box Vein are similar to characteristics of shield brines described by Frape and Fritz in Canadian basement rocks.

  20. Amniotic Fluid

    PubMed Central

    Smith, Heather C.; Muglia, Louis J.; Morrow, Ardythe L.

    2014-01-01

    Our aim was to review the use of high-dimensional biology techniques, specifically transcriptomics, proteomics, and metabolomics, in amniotic fluid to elucidate the mechanisms behind preterm birth or assessment of fetal development. We performed a comprehensive MEDLINE literature search on the use of transcriptomic, proteomic, and metabolomic technologies for amniotic fluid analysis. All abstracts were reviewed for pertinence to preterm birth or fetal maturation in human subjects. Nineteen articles qualified for inclusion. Most articles described the discovery of biomarker candidates, but few larger, multicenter replication or validation studies have been done. We conclude that the use of high-dimensional systems biology techniques to analyze amniotic fluid has significant potential to elucidate the mechanisms of preterm birth and fetal maturation. However, further multicenter collaborative efforts are needed to replicate and validate candidate biomarkers before they can become useful tools for clinical practice. Ideally, amniotic fluid biomarkers should be translated to a noninvasive test performed in maternal serum or urine. PMID:23599373

  1. Developing Inclusivity.

    ERIC Educational Resources Information Center

    Layer, Geoff

    2002-01-01

    Comparison of Higher Education Funding Council for England initiatives for widening participation with those in Australia shows they are focused on recruitment and enrollment. However, to achieve inclusion requires more attention to provision based on learner needs, increased financial support for disadvantaged groups, and clear targets in higher…

  2. Inclusion Means...

    ERIC Educational Resources Information Center

    Keefe, Charlotte Hendrick; Davis, Ruth

    1998-01-01

    Under current law, public and private institutions must educate children with disabilities just as they educate other children. Inclusion becomes a civil-rights issue when special-education students' rights are perceived to be violated because of unequal treatment due to segregated programs. A survey of attendees at a summer training institute on…

  3. Coupled measurement of δ18O/δD in gypsum hydration water and salinity of fluid inclusions in gypsum: A novel tool for reconstructing parent water chemistry and depositional environment

    NASA Astrophysics Data System (ADS)

    Evans, Nick; Gázquez, Fernando; Turchyn, Alexandra; Chapman, Hazel; Hodell, David

    2015-04-01

    The measurement of oxygen and hydrogen isotopes in gypsum hydration water (CaSO4•2H2O) is a powerful tool to determine the isotopic composition of the parent fluid from which gypsum precipitated. To be useful, however, the hydration water must retain its original isotope signal and not have undergone postdepositional exchange. We developed a novel method to ascertain whether hydration waters have secondarily exchanged by coupling oxygen and hydrogen isotopes of gypsum hydration water with the salinities of fluid inclusions. Salinity is obtained through microthermometric analysis of the same gypsum crystals measured for hydration water by freezing the sample and then measuring the melting point of the fluid inclusions. We apply the method to Messinian gypsum deposits of Cycle 6 within the Yesares Member, Río de Aguas section, Sorbas Basin (SE Spain). After correction of oxygen and hydrogen isotopes of gypsum hydration water for fractionation factors, the estimated range of the mother water is -1.8o to 2.8o for δ18O and -12.5o to 16.3o for δD. In the same samples, estimated salinity of primary fluid inclusions range from 18 to 51ppt. Salinity is highly correlated with δ18O and δD, yielding an r2 of 0.88 and 0.87, respectively. The intercepts of the regression equations (i.e., at zero salinity) define the isotope composition of the freshwater endmember, and average -4.4±1.3o for δ18O and -28.9±8.7o for δD. These values are within error of the average isotope composition of precipitation and groundwater data from the local region of Almería today (-4.3o and -22.2o for δ18O and δD, respectively). This agreement provides strong evidence that the gypsum hydration water has retained its isotope composition and has not undergone postdepositional exchange. Furthermore, the isotope and salinity values indicate a significant contribution of meteoric water during gypsum deposition. This observation contrasts with sulfur and oxygen isotopes in sulfate (21.9 > δ34S

  4. Stiffening solids with liquid inclusions

    NASA Astrophysics Data System (ADS)

    Style, Robert W.; Boltyanskiy, Rostislav; Allen, Benjamin; Jensen, Katharine E.; Foote, Henry P.; Wettlaufer, John S.; Dufresne, Eric R.

    2015-01-01

    From bone and wood to concrete and carbon fibre, composites are ubiquitous natural and synthetic materials. Eshelby’s inclusion theory describes how macroscopic stress fields couple to isolated microscopic inclusions, allowing prediction of a composite’s bulk mechanical properties from a knowledge of its microstructure. It has been extended to describe a wide variety of phenomena from solid fracture to cell adhesion. Here, we show experimentally and theoretically that Eshelby’s theory breaks down for small liquid inclusions in a soft solid. In this limit, an isolated droplet’s deformation is strongly size-dependent, with the smallest droplets mimicking the behaviour of solid inclusions. Furthermore, in opposition to the predictions of conventional composite theory, we find that finite concentrations of small liquid inclusions enhance the stiffness of soft solids. A straightforward extension of Eshelby’s theory, accounting for the surface tension of the solid-liquid interface, explains our experimental observations. The counterintuitive stiffening of solids by fluid inclusions is expected whenever inclusion radii are smaller than an elastocapillary length, given by the ratio of the surface tension to Young’s modulus of the solid matrix. These results suggest that surface tension can be a simple and effective mechanism to cloak the far-field elastic signature of inclusions.

  5. Mesozoic vein-type Pb-Zn mineralization in the Pyrenees: Lead isotopic and fluid inclusion evidence from the Les Argentières and Lacore deposits

    NASA Astrophysics Data System (ADS)

    Munoz, Marguerite; Baron, Sandrine; Boucher, Adrien; Béziat, Didier; Salvi, Stefano

    2016-03-01

    The Axial Zone of the Pyrenees contains numerous sedimentary-exhalative Pb-Zn deposits formed during the Early Palaeozoic, which have been the subject of several studies. In addition to these, base-metal vein-type mineralizations are also exposed within the Axial Zone metasediments. These deposits, however, have not been investigated in depth and the timing and geodynamic context of their formation has not been specifically addressed. The vein-type Pb-Zn deposits of Les Argentières and Lacore are located in Devonian terranes of the eastern Pyrenees, south of the Mesozoic Aulus basin. They are interpreted as having been emplaced under an extensional setting. They are characterized by silver-rich tetrahedrite that occurs with Pb-Zn sulphides deposited by low-temperature NaCl-CaCl2 brines. Lead isotopic 208Pb/204Pb and 206Pb/204Pb ratios acquired on galena show more radiogenic values compared to those from the Palaeozoic sedimentary-exhalative mineralization, thus indicating younger ages. According to the model ages, the formation of the two deposits may be narrowed down to middle Late Triassic and Late Jurassic periods, respectively, which allows us to argue in favour of the role of pre-Alpine rifting phases in hydrothermal fluids circulation and mineralization deposition in a vein system bounding the Mesozoic Aulus basin.

  6. Genetics Home Reference: microvillus inclusion disease

    MedlinePlus

    ... of nutrients from food during digestion, resulting in malnutrition and dehydration. Affected infants often have difficulty gaining ... and fluids during digestion leads to recurrent diarrhea, malnutrition, and dehydration in individuals with microvillus inclusion disease . ...

  7. Selective copper diffusion into quartz-hosted vapor inclusions: Evidence from other host minerals, driving forces, and consequences for Cu-Au ore formation

    NASA Astrophysics Data System (ADS)

    Seo, Jung Hun; Heinrich, Christoph A.

    2013-07-01

    Recent experimental studies have raised concerns that Cu concentrations in quartz-hosted fluid inclusions from magmatic-hydrothermal ore deposits do not represent pristine concentrations in the trapped fluids, but are modified by post-entrapment diffusional exchange through the host quartz. New microanalyses of fluid inclusions hosted in topaz show significantly lower Cu concentrations in vapor inclusions, compared to otherwise identical inclusions hosted by coexisting quartz, whereas coeval brine (hypersaline liquid) inclusions are very similar independent of host mineral in one sample. Sulfur is present as a major component in all vapor inclusions, as in most porphyry-related vapor inclusions, and Cu never exceeds S, but commonly matches the S content at a molar ratio of Cu:S ⩽ 2 in vapor inclusions hosted by quartz. Univalent ions with a radius smaller than ˜1 Å are known to diffuse rapidly through the channels of the quartz structure, parallel to its crystallographic c axis. Since only Cu concentrations differ between topaz- and quartz-hosted inclusions, we hypothesize that Cu+ and H+ re-equilibrate by diffusional ion exchange through these channels, while all other element concentrations remain essentially unchanged. A thermodynamic model considering charge-balanced Cu+H+ exchange and diffusive H2 re-equilibration of an initially Cu-poor but S-rich vapor inclusion with a typical rock-buffered fluid environment outside the host crystal demonstrates a strong chemical driving force for Cu+ to migrate from the surrounding rock into the fluid inclusion during cooling of the system. The driving force for Cu diffusion, against the gradient in total Cu concentration, is the abundant H+ liberated inside the inclusion by dissociation of HCl and particularly by the precipitation of CuFeS2 by reaction with the initially trapped H2S and/or SO2. Gold is not only a much larger ion, but is subject to an opposing driving force, suggesting that high concentrations of this

  8. Immiscibility of Fluid Phases at Magmatic-hydrothermal Transition: Formation of Various PGE-sulfide Mineralization for Layered Basic Intrusions

    NASA Astrophysics Data System (ADS)

    Zhitova, L.; Borisenko, A.; Morgunov, K.; Zhukova, I.

    2007-12-01

    Fluid inclusions in quartz of the Merensky Reef (Bushveld Complex, South Africa) and the Chineisky Pluton (Transbaikal Region, Russia) were studied using cryometry, microthermometry, Raman-spectroscopy, LA ICP- MS, scanning electronic microscopy, gas-chromatography and isotopic methods. This allowed us to document some examples of fluid phase separation resulting in formation of different types of PGE-sulfide mineralization for layered basic intrusions. The results obtained show at least three generations of fluid separated from boiling residual alumosilicate intercumulus liquid of the Merensky Reef. The earliest fluid phase composed of homogenous high-dense methane and nitrogen gas mixture was identified in primary gas and co-existing anomalous fluid inclusions from symplectitic quartz. The next generation, heterophase fluid, composed of brines containing a free low-dense (mostly of carbon dioxide) gas phase, was observed in primary multiphase and coexisting gas-rich inclusions of miarolitic quartz crystals. The latest generation was also a heterophase fluid (low salinity water-salt solution and free low-dense methane gas phase) found in primary water-salt and syngenetic gas inclusions from peripheral zones of miarolitic quartz crystals. For the Chineisky Pluton reduced endocontact magmatogene fluids changed to oxidized low salinity hydrothermal fluids in exocontact zone. This resulted in formation of sulfide-PGE enrichment marginal zones of intrusion. The results obtained give us a possibility to suggest that: 1) Fluid phase separation is a typical feature of magmatogene fluids for layered basic intrusions. 2) Reduced fluids can extract and transport substantial PGE and sulfide concentrations. 3) Oxidation of reduced fluids is one of the most important geochemical barriers causing abundant PGE minerals and sulfides precipitation. This in turn results in both formation of PGE reefs or enriched contact zones of layered basic intrusions. This work was supported by

  9. Carbonatitic mineralogy of natural diamond-forming fluids

    NASA Astrophysics Data System (ADS)

    Kopylova, M.; Navon, O.; Dubrovinsky, L.; Khachatryan, G.

    2010-03-01

    A suite of 20 cuboid fibrous diamonds from the Democratic Republic of Congo was studied to determine mineral phases crystallized from diamond-forming fluids that were trapped as inclusions in diamonds. We identified minerals and non-crystalline components using their compositional trends in the electron microprobe analyses of inclusions, an innovative bulk X-ray diffraction analysis and characteristic FTIR and Raman peaks. The DRC diamonds contain fluid inclusions of the Ca-carbonatitic-silicic composition. Most common phases precipitated from the fluid are found to be high-Si micas (90-30% of the solids volume), complex non-crystalline Na-Ca-Mg-Fe carbonate matter and apatite (together 5-70%), leaving a residual aqueous solution of K, Cl and carbonate ions and gaseous CO 2. A notable absence of carbonate minerals in bulk X-ray diffraction patterns combined with the vibrational spectroscopy observations on the C-O bonds indicates that C may be included in dissolved or amorphous carbonate matter. The modes of the most abundant phases are controlled by chemical trends of the bulk fluid compositions. Other relatively rare ˜ 30 minerals, including various minerals with structural and coordinated H 2O, are detected by the vibrational spectroscopic and X-ray analyses. The fluid also contains some hydrocarbons associated with the carbonate material. The presence of some rare minerals and exotic compositions of solid-solution minerals in the fluid suggest crystallization from a closed system with high salinity-high aH 2O-high aCO 2 composition that persisted to relatively low temperatures and pressures. The bulk of the fluid crystallized in the diamond stability field ( P < 7 GPa, T < 950 °C), but continued to form hydrocarbons, accessory and deuteric phases down to 200 °C and 0.2 GPa. Overall, the mineralogy of the fluid resembles carbonatite.

  10. Genesis of amethyst geodes in basaltic rocks of the Serra Geral Formation (Ametista do Sul, Rio Grande do Sul, Brazil): a fluid inclusion, REE, oxygen, carbon, and Sr isotope study on basalt, quartz, and calcite

    NASA Astrophysics Data System (ADS)

    Gilg, H. Albert; Morteani, Giulio; Kostitsyn, Yuri; Preinfalk, Christine; Gatter, Istvan; Strieder, Adelir J.

    2003-12-01

    In the Ametista do Sul area, Rio Grande do Sul, Brazil, amethyst-bearing geodes are hosted by a ~40- to 50-m-thick subhorizontal high-Ti basaltic lava flow of the Lower Cretaceous Paraná Continental Flood Basalt Province. The typically spherical cap-shaped, sometimes vertically elongated geodes display an outer rim of celadonite followed inwards by agate and colorless and finally amethystine quartz. Calcite formed throughout the whole crystallization sequence, but most commonly as very late euhedral crystals, sometimes with gypsum, in the central cavity. Fluid inclusions in colorless quartz and amethyst are predominantly monophase and contain an aqueous liquid. Two-phase liquid-vapor inclusions are rare. Some with a consistent degree of fill homogenize into the liquid between 95 and 98 °C. Ice-melting temperatures in the absence of a vapor phase between -4 and +4 °C indicate low salinities. Chondrite-normalized REE patterns of calcites are highly variable and show generally no systematic correlation with the paragenetic sequence. The oxygen isotope composition of calcites is very homogeneous (δ18OVSMOW=24.9±1.1‰, n=34) indicating crystallization temperatures of less than 100 °C. Carbon isotope values of calcites show a considerable variation ranging from -18.7 to -2.9‰ (VPDB). The 87Sr/86Sr ratio of calcites varies between 0.706 and 0.708 and is more radiogenic than that of the host basalt (~0.705). The most likely source of silica, calcium, carbon, and minor elements in the infill of the geodes is the highly reactive interstitial glass of the host basalts leached by gas-poor aqueous solutions of meteoric origin ascending from the locally artesian Botucatú aquifer system in the footwall of the volcanic sequence. The genesis of amethyst geodes in basalts at Ametista do Sul, Brazil, is thus considered as a two-stage process with an early magmatic protogeode formation and a late, low temperature infill of the cavity.

  11. Diversity in C-Xanes Spectra Obtained from Carbonaceous Solid Inclusions from Monahans Halite

    NASA Technical Reports Server (NTRS)

    Kebukawa, Y.; Zolensky, M. E.; Fries, M.; Kilcoyne, A. L. D.; Rahman, Z.; Cody, G. D.

    2014-01-01

    Monahans meteorite (H5) contains fluid inclusion- bearing halite (NaCl) crystals [1]. Microthermometry and Raman spectroscopy showed that the fluid in the inclusions is an aqueous brine and they were trapped near 25degC [1]. Their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism [2]. Abundant solid inclusions are also present in the halites. The solid inclusions include abundant and widely variable organics [2]. Analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction and TEM reveal that these grains include macromolecular carbon similar