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Sample records for basinal ore fluids

  1. Metallogeny of the Great Basin: crustal evolution, fluid flow, and ore deposits

    Science.gov (United States)

    Hofstra, Albert H.; Wallace, Alan R.

    2006-01-01

    The Great Basin physiographic province in the Western United States contains a diverse assortment of world-class ore deposits. It currently (2006) is the world's second leading producer of gold, contains large silver and base metal (Cu, Zn, Pb, Mo, W) deposits, a variety of other important metallic (Fe, Ni, Be, REE's, Hg, PGE) and industrial mineral (diatomite, barite, perlite, kaolinite, gallium) resources, as well as petroleum and geothermal energy resources. Ore deposits are most numerous and largest in size in linear mineral belts with complex geology. U.S. Geological Survey (USGS) scientists are in the final year of a research project initiated in the fall of 2001 to increase understanding of relations between crustal evolution, fluid flow, and ore deposits in the Great Basin. Because of its substantial past and current mineral production, this region has been the focus of numerous investigations over the past century and is the site of ongoing research by industry, academia, and state agencies. A variety of geoinformatic tools was used to organize, reinterpret, and display, in space and time, the large amounts of geologic, geophysical, geochemical, and hydrologic information deemed pertinent to this problem. This information, in combination with concentrated research on (1) critical aspects of the geologic history, (2) an area in northern Nevada that encompasses the major mineral belts, and (3) important mining districts and deposits, is producing new insights about the interplay between key tectonic events, hydrothermal fluid flow, and ore genesis in mineral belts. The results suggest that the Archean to Holocene history of the Great Basin was punctuated by several tectonic events that caused fluids of different origins (sea water, basinal brine, meteoric water, metamorphic water, magmatic water) to move through the crust. Basement faults reactivated during these events localized deformation, sedimentation, magmatism, and hydrothermal fluid flow in overlying

  2. Coupled Heat and Fluid Flow Modeling of the Earth's Largest Zinc Ore Deposit at Red Dog, Alaska: Implications for Structurally-Focused, Free Convection in Submarine Sedimentary Basins

    Science.gov (United States)

    Garven, G.; Dumoulin, J. A.; Bradley, D. A.; Young, L. E.; Kelley, K. D.; Leach, D. L.

    2002-12-01

    Crustal heat flow can provide a strong mechanism for driving groundwater flow, particularly in submarine basins where other mechanisms for driving pore fluid flow such as topography, compaction and crustal deformation are too weak or too slow to have a significant effect on disturbing conductive heat flow. Fault zones appear to play a crucial role in focusing fluid migration in basins, as inferred in ancient rocks by many examples of hydrothermal deposits of sediment-hosted ores worldwide. Many rift-hosted deposits of lead, zinc, and barite ore appear to have formed at or near the seafloor by focused venting of hot basinal fluids and modified seawater, although the geophysical nature of these systems is not so well known. For example, the upper Kuna Formation, a finely laminated, black, organic-rich siliceous mudstone and shale in the Western Brooks Range of northwest Alaska, is host to the largest resources of zinc yet discovered in the Earth's crust, containing ore reserves in excess of 175 Mt averaging about 16% Zn and 5% Pb. Although situated today in a highly-deformed series of structural allocthonous plates thrusted during the Jurassic to Cretaceous Brookian Orogeny, the stratiform ores are thought to have formed much earlier in the anoxic, mud-rich Carboniferous-age Kuna Basin when adjacent carbonate platforms were drowned by rifting and tectonic subsidence. Fluid inclusion studies of ore-stage sphalerite and gangue minerals indicate sub-seafloor mineralization temperatures less than 200oC and most likely between 120 to 150 oC, during a period of sediment diagenesis and extensional faulting. We have constructed fully-coupled numerical models of heat and fluid flow to test hydrologic theories for free convection, submarine venting and subsequent ore formation, as constrained by paleoheat flow and petrologic observations. A finite element grid was designed and adapted for a cross section of the Kuna Basin, geologically restored to latest Mississippian time

  3. Coupled heat and fluid flow modeling of the Carboniferous Kuna Basin, Alaska: Implications for the genesis of the Red Dog Pb-Zn-Ag-Ba ore district

    Science.gov (United States)

    Garven, G.; Raffensperger, J.P.; Dumoulin, J.A.; Bradley, D.A.; Young, L.E.; Kelley, K.D.; Leach, D.L.

    2003-01-01

    The Red Dog deposit is a giant 175 Mton (16% Zn, 5% Pb), shale-hosted Pb-Zn-Ag-Ba ore district situated in the Carboniferous Kuna Basin, Western Brooks Range, Alaska. These SEDEX-type ores are thought to have formed in calcareous turbidites and black mudstone at elevated sub-seafloor temperatures (120-150??C) within a hydrogeologic framework of submarine convection that was structurally organized by large normal faults. The theory for modeling brine migration and heat transport in the Kuna Basin is discussed with application to evaluating flow patterns and heat transport in faulted rift basins and the effects of buoyancy-driven free convection on reactive flow and ore genesis. Finite element simulations show that hydrothermal fluid was discharged into the Red Dog subbasin during a period of basin-wide crustal heat flow of 150-160 mW/m2. Basinal brines circulated to depths as great as 1-3 km along multiple normal faults flowed laterally through thick clastic aquifers acquiring metals and heat, and then rapidly ascended a single discharge fault zone at rates ??? 5 m/year to mix with seafloor sulfur and precipitate massive sulfide ores. ?? 2003 Elsevier Science B.V. All rights reserved.

  4. Stable isotope characteristics and origin of ore-forming fluids in copper-gold-polymetallic deposits within strike-slip pull-apart basin of Weishan-Yongping continental collision orogenic belt, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    WANG Yong; HOU Zengqian; MO Xuanxue; DONG Fangliu; BI Xianmei; ZENG Pusheng

    2007-01-01

    More than 140 middle-small sized deposits or minerals are present in the Weishan-Yongping ore concentra-tion area which is located in the southern part of a typical Lanping strike-slip and pull-apart basin. It has plenty of mineral resources derived from the collision between the Indian and Asian plates. The ore-forming fluid system in the Weishan-Yongping ore concentration area can be divided into two subsystems, namely, the Zijinshan subsystem and Gonglang arc subsystem. The ore-forming fluids of Cu, Co deposits in the Gonglang arc fluid subsystem have δD values between -83.8‰ and -69%0, δ18O values between 4.17‰ and 10.45‰, and δ13C values between -13.6‰ and 3.7‰,suggesting that the ore-forming fluids of Cu, Co deposits were derived mainly from magmatic water and partly from formation water. The ore-forming fluids of Au, Pb, Zn, Fe deposits in the Zijinshan subsystem have δD values between-117.4‰ and-76‰, δ18O values between 5.32‰ and 9.56‰,and δ13C values between -10.07‰ and -1.5‰. The ore-forming fluids of Sb deposits have 6D values between -95%0 and -78‰, δ18O values between 4.5‰ and 32.3‰, and δ13 Cvalues between -26.4‰ and -1.9‰. Hence, the ore-forming fluids of the Zijinshan subsystem must have been derived mainly from formation water and partly from magmatic water.Affected by the collision between the Indian and Asian plates,ore-forming fluids in Weishan-Yongping basin migrated con-siderably from southwest to northeast. At first, the Gonglang arc subsystem with high temperature and high salinity was formed. With the development of the ore-forming fluids, the Zijinshan subsystem with lower temperature and lower salinity was subsequently formed.

  5. Transport of Pb and Zn by carboxylate complexes in basinal ore fluids and related petroleum-field brines at 100°C: the influence of pH and oxygen fugacity

    Directory of Open Access Journals (Sweden)

    Giordano Thomas H

    2002-09-01

    Full Text Available It is well established through field observations, experiments, and chemical models that oxidation (redox state and pH exert a strong influence on the speciation of dissolved components and the solubility of minerals in hydrothermal fluids. log –pH diagrams were used to depict the influence of oxygen fugacity and pH on monocarboxylate- and dicarboxylate-transport of Pb and Zn in low-temperature (100°C hydrothermal ore fluids that are related to diagenetic processes in deep sedimentary basins, and allow a first-order comparison of Pb and Zn transport among proposed model fluids for Mississippi Valley-type (MVT and red-bed related base metal (RBRBM deposits in terms of their approximate pH and conditions. To construct these diagrams, total Pb and Zn concentrations and Pb and Zn speciation were calculated as a function of log and pH for a composite ore-brine with concentrations of major elements, total sulfur, and total carbonate that approximate the composition of MVT and RBRBM model ore fluids and modern basinal brines. In addition to acetate and malonate complexation, complexes involving the ligands Cl-, HS-, H2S, and OH- were included in the model of calculated total metal concentration and metal speciation. Also, in the model, Zn and Pb are competing with the common-rock forming metals Ca, Mg, Na, Fe, and Al for the same ligands. Calculated total Pb concentration and calculated total Zn concentration are constrained by galena and sphalerite solubility, respectively. Isopleths, in log –pH space, of the concentration of Pb and concentration of Zn in carboxylate (acetate + malonate complexes illustrate that the oxidized model fluids of T. H. Giordano (in Organic Acids in Geological Processes, ed. E. D. Pittman and M. D. Lewan, Springer-Verlag, New York, 1994, pp. 319–354 and G. M. Anderson (Econ. Geol., 1975, 70, 937–942 are capable of transporting sufficient amounts of Pb (up to 10 ppm and Zn (up to 100 ppm in the form of carboxylate

  6. Geothermal and fluid flowing simulation of ore-forming antimony deposits in Xikuangshan

    Institute of Scientific and Technical Information of China (English)

    YANG Ruiyan; MA Dongsheng; BAO Zhengyu; PAN Jiayong; CAO Shuanglin; XIA Fei

    2006-01-01

    The Xikuangshan Antimony Deposit located in the Mid-Hunan Basin, China, is the largest antimony deposit in the world. Based on the hydrogeological and geochemical data collected from four sections, Xikuangshan-Dajienao (AO), Xikuangshan-Dashengshan (BO), Xikuangshan-Longshan (CO) and Dafengshan (DO) in the Basin, an advanced metallogenic model related to deep-cyclic meteoric water of Xikuangshan Antimony Deposit is put forward in this paper using a model of heat-gravity-driving fluid flow transportation. The simulation results show that the ore-forming fluid of the deposit mainly comes from the Dashengshan and Longshan areas where BO and CO sections are located if the overall basin keeps a constant atmospheric precipitation and infiltration rate during mineralization, and that the average transportation speed of the ore-forming fluids is about 0.2-0.4 m/a.

  7. Ore fluid geochemistry of the Jinlongshan Carlin type gold ore belt in Shaanxi Province, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Jinlongshan gold ore belt in southern Shaanxi Province contains a number of Carlin-type gold deposits in the Qinling collisional orogenic belt. Their fluid inclusions are of the Na+ - Cl- type. From the main metallogenic stage to later stages, the total quantity of anions and cations, temperature and deoxidation parameter (R) for fluid inclusions all gradu ally decreased, suggesting the gradual intensification of fluid oxidation, the reduction of met allogenic depth and the input of meteoric water and organic components. The deposits were formed during crustal uplifting and hence had similar tectonic settings to orogenic gold depos its. The CO2 contents and CO2/H2O values of the ore fluid increased from early to late sta ges, and the wall-rock alteration is represented by decarbonation, which is inconsistent with the characteristics of orogenic gold deposits. It is also discovered that Na + , K + ,SO42-, Cl-and the total amounts of anions and cations in the inclusions in quartz are higher than those in the coexisting calcite. The H, O and C isotope ratios indicate that the ore fluid was sourced from meteoric water and metamorphic devolatilisation of the sedimentary rocks that host the ores. The high background δ18O and δ13C values of wall rocks resulted in high δ18O and δ13 C values of ore fluid and also high δ 18 O and δ 13 C values of hydrothermal minerals such as quartz and carbonate. The carbon in ore fluid stemmed largely from the hosting strata. The δ 18O and δ13C values of Fe-calcite and the δD values of fluid inclusions are lower than those of calcite and quartz. In terms of the theory of coordination chemistry, all these differences can be ascribed to water-rock interaction in the same fluid system, instead, to the multi source of ore fluid.

  8. The Geohydrology of MVT-Ore Genesis in the Canning Basin, Western Australia

    Science.gov (United States)

    Garven, G.; Wallace, M. M.

    2009-05-01

    In the Lennard Shelf, Western Australia, epigenetic MVT-type Pb-Zn mineralization occurs in Middle Devonian evaporitic dolomites which were part of a barrier reef system (Hurley & Lohmann, 1989). Ore mineralization exhibits a strong structural control at the basin scale and normal faults probably controlled pathways for brine and petroleum migration that affected ore deposition (Wallace et al., 1999). For the Canning basin, finite element simulations show that compaction was the most important process for creating overpressures and driving basinal fluids in this thick extensional basin. Basinal fluids are shown to have been driven across the Fitzroy Trough through permeable and deeply buried Silurian-Ordovician aquifer units. The fluids then migrated upwards at rates of m/yr up during periods of episodic extension (Braun, 1992) where fluid flow was channeled by major normal fault zones like the Cadjebut and Pinnacles Faults. Reactive flow simulations test a petroleum-reservoir model for mineralization whereby metal-bearing brines mix with accumulated hydrocarbons (Anderson & Garven, 1987). The results show that compaction-driven flow, as proposed by Beales & Jackson (1966) and Jackson & Beales (1967), works rather well in this ore district--other mechanisms such as sealevel tidal pumping (Cathles, 1988) or topographic drive (Solomon & Groves, 1994) are more tenuous and really unnecessary from a mass transport or geohydrologic basis.

  9. Isotope geochemistry of ore fluids for the Dongsheng sandstone-type uranium deposit,China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Dongsheng sandstone-type uranium deposit is one of the large-sized sandstone-type uranium deposits discovered in the northern part of the Ordos Basin of China in recent years. Geochemical characteristics of the Dongsheng uranium deposit are significantly different from those of the typical interlayered oxidized sandstone-type uranium ore deposits in the region of Middle Asia. Fluid inclusion studies of the uranium deposit showed that the uranium ore-forming temperatures are within the range of 150-160℃. Their 3He/4He ratios are within the range of 0.02-1.00 R/Ra, about 5-40 times those of the crust. Their 40Ar/36Ar ratios vary from 584 to 1243, much higher than the values of atmospheric argon. The δ18OH2O and δD values of fluid inclusions from the uranium deposit are -3.0‰- -8.75‰ and -55.8‰- -71.3‰, respectively, reflecting the characteristics of mixed fluid of meteoric water and magmatic water. The δ18OH2O and δD values of kaolinite layer at the bottom of the uranium ore deposit are 6.1‰ and -77‰, respectively, showing the characteristics of magmatic water. The δ13CV-PDB and δ18OH2O values of calcite veins in uranium ores are -8.0‰ and 5.76‰, respectively, showing the characteristics of mantle source. Geochemical characteristics of fluid inclusions indicated that the ore-formation fluid for the Dongsheng uranium deposit was a mixed fluid of meteoric water and deep-source fluid from the crust. It was proposed that the Jurassic-Cretaceous U-rich metamorphic rocks and granites widespread in the northern uplift area of the Ordos Basin had been weathered and denudated and the ore-forming elements, mainly uranium, were transported by meteoric waters to the Dongsheng region, where uranium ores were formed. Tectonothermal events and magmatic activities in the Ordos Basin during the Mesozoic made fluids in the deep interior and oil/gas at shallow levels upwarp along the fault zone and activated fractures, filling into U-bearing clastic

  10. Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

    Science.gov (United States)

    Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

    2015-04-01

    India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled

  11. Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin, Southwestern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic: ocean-continent transformation (late Paleozoic to early mid-Triassic); intracontinental rift basin (late mid-Triassic to early Jurassic); down-warped basin (middle to late Jurassic); foreland basin (Cretaceous); and strike-slip basin (Cenozoic). Three major genetic types of Ag-Cu polymetailic ore deposits, including the reworked hydrothermal sedimentary, sedimentary-hydrothermally reworked and hydrothermal vein types, are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages. Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation, migration direction and emplacement processes of the basin fluids, thus causing differences in mineralization styles as well as in genetic types of ore deposit.

  12. Fluid inclusion, rare earth element geochemistry, and isotopic characteristics of the eastern ore zone of the Baiyangping polymetallic Ore district, northwestern Yunnan Province, China

    Science.gov (United States)

    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

  13. Fluid flow and mineralization of Youjiang Basin in the Yunnan-Guizhou-Guangxi area, China

    Institute of Scientific and Technical Information of China (English)

    王国芝; 胡瑞忠; 苏文超; 朱赖民

    2003-01-01

    Comprehensive studies, based on isotope geochemistry of C, H, O, S and Sr, chronology, common element and trace element geochemistry of fluid inclusions for the epithermal Au, As, Sb and Hg deposits in the Youjiang Basin and its peripheral areas, suggested that the ore fluid was the basin fluid with abundant metallic elements and the large-scale fluid flow of the same source in the late Yenshan stage was responsible for huge epithermal mineralization and silicification. The ore fluid flowed from the basin to the platform between the basin and the platform and migrated from the inter-platform basin to the isolated platform in the Youjiang Basin. The synsedimentary faults and paleokast surface acted respectively as main conduits for vertical and lateral fluid flow.

  14. Characteristics and origin of ore-forming fluids of Jinchangqing gold (copper) ore deposit (s) in Xiangyun, Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    HE Mingqin; SONG Huanbin; LIU Jiajun; LI Chaoyang

    2005-01-01

    On the basis of results of the studies of primary fluid inclusions, and the hydrogen and oxygen isotope data, the authors concluded that the early-stage ore-forming fluid from the Jinchangqing gold (copper) ore deposit is a kind of sulfate type hot brine characterized by medium temperature and salinity, genetically related to the late-stage ore-forming fluid derived from an acidic and more reductive environment. However, the late-stage ore-forming fluid is a sort of low temperature and low salinity chloride-type hot brine which originated from a lower pressure, acidic and more oxidative environment. In general, the ore fluids were derived from the late-stage, or largely from the early-stage groundwater-derived meteoric water, which has a 12‰-17‰ heavier oxygen isotopic composition than the original rain water (δ 18 O= -15.3‰ ), and were formed during gold mineralization as a product of oxygen isotope exchange during the reaction between ore-forming fluid and wall rocks under a lower water/rock ratio condition.

  15. Ore-Forming Fluid Characteristics of the Naoyangping-Damogou zinc-fluorite ore deposit, Pingli County, Shaanxi Province, China

    Directory of Open Access Journals (Sweden)

    Moussounda Kounga Claude1

    2013-01-01

    Full Text Available The Naoyangping-Damogou zinc-fluorite ore deposit is located in the North Dabashan Caledonian fold belt, in the east wing Pingli Anticlinorium, which is one of the most important zinc-fluorite-hosting faults in Shaanxi Province of China. Metallogenesis is controlled by F7 fault structure and other relevant fault structure systems and closely related to the trachyte side. Fluid inclusion (FI petrography and microthermometry, and analysis of oxygen and hydrogen isotopes for fluid inclusions were conducted to determine the characteristics of the ore-forming fluids and the processes of zinc and fluorite mineralizations. Microthermometry data of FI indicated that ore-forming fluids are characterized by low salinity and low density. The data obtained from geothermometric studies of Sphalerite and fluorite associated with zinc-lead mineralization at the Naoyangping-Damogou mine are compatible with a structurally controlled, Sedimentaryhydrothermal origin. Homogenization and last ice melting temperature of primary fluid inclusion indicate that mineralization taken place over a temperature range 295-335°C and salinities of inclusion fluids range 0.53 to 1.33 wt.% TDS. Ore-forming fluids were dominated by magmatic components in the early mineralization period. In the present paper we report our preliminary research results of the data obtained from geothermometric studies of Sphalerite and fluorite at the Naoyangping-Damogou ore deposit. The present study builds on the existing geological, petrographic and geochemical information of Naoyangping-Damogou

  16. Complexity and Geodynamics of Ore-accumulating Basins in the Qinling Orogenic Belt, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Researches were made of different continental-margin and intraplate basin systems in the Qinling microplate in terms of hydrothermal deposition, geodynamics of basin formation, hydrothermal sedimentary rock facies, syntectonics in the basins, and the styles of ore accumulation in the basins.

  17. Organic Gases in Fluid Inclusions of Ore Minerals and Their Constraints on Ore Genesis: A Case Study of the Changkeng Au-Ag Deposit, Guangdong, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The newly discovered Changkeng Au-Ag deposit is a new type of sediment-hosted precious metal deposit. Most of the previous researchers believed that the deposit was formed by meteoric water convection. By using a high vacuum quadrupole gas mass spectrometric system, nine light hydrocarbons have been recognized in the fluid inclusions in ore minerals collected from the Changkeng deposit. The hydrocarbons are composed mainly of saturated alkanes C1-4 and unsaturated alkenes C2-4 and aromatic hydrocarbons, in which the alkanes are predominant, while the contents of alkenes and aromatic hydrocarbons are very low. The Σalka/Σalke ratio of most samples is higher than 100, suggesting that those hydrocarbons are mainly generated by pyrolysis of kerogens in sedimentary rocks caused by water-rock interactions at medium-low temperatures, and the metallogenic processes might have not been affected by magmatic activity. A thermodynamic calculation shows that the light hydrocarbons have reached chemical equilibrium at temperatures higher than 200?C, and they may have been generated in the deep part of sedimentary basins (e.g., the Sanzhou basin) and then be transported by ore-forming fluids to a shallow position of the basin via a long distance. Most of the organic gases are generated by pyrolysis of the type II kerogens (kukersite) in sedimentary host rocks, only a few by microorganism activity. The compositions and various parameters of light hydrocarbons in gold ores are quite similar to those in silver ores, suggesting that the gold and silver ores may have similar metallogenic processes. Based on the compositions of organic gases in fluid inclusions, the authors infer that the Changkeng deposit may be of a tectonic setting of continental rift. The results of this study support from one aspect the authors' opinion that the Changkeng deposit is not formed by meteoric water convection, and that its genesis has a close relationship with the evolution of the Sanzhou basin, so

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

    Science.gov (United States)

    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 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. The world-class Jinding Zn-Pb deposit: ore formation in an evaporite dome, Lanping Basin, Yunnan, China

    Science.gov (United States)

    Leach, David L.; Song, Yu-Cai; Hou, Zeng-Qian

    2016-07-01

    The Jinding Zn-Pb sediment-hosted deposit in western Yunnan, China, is the fourth largest Zn deposit in Asia. Based on field observations of the ore textures, breccias, and the sandstone host rocks, the ores formed in a dome that was created by the diapiric migration of evaporites in the Lanping Basin during Paleogene deformation and thrust loading. Most of the ore occurs in sandstones that are interpreted to be a former evaporite glacier containing a mélange of extruded diapiric material, including breccias, fluidized sand, and evaporites that mixed with sediment from a fluvial sandstone system. A pre-ore hydrocarbon and reduced sulfur reservoir formed in the evaporite glacier that became the chemical sink for Zn and Pb in a crustal-derived metalliferous fluid. In stark contrast to previous models, the Jinding deposit does not define a unique class of ore deposits; rather, it should be classified as MVT sub-type hosted in a diapiric environment. Given that Jinding is a world-class ore body, this new interpretation elevates the exploration potential for Zn-Pb deposit in other diapir regions in the world.

  20. N2-Ar-He systematics and source of ore-forming fluid in Changkeng Au-Ag deposit, central Guangdong, China

    Institute of Scientific and Technical Information of China (English)

    孙晓明; 孙凯; 陈炳辉; 陈敬德; David; I.Norman

    1999-01-01

    Changkeng Au-Ag deposit is a newly-discovered new type precious metal deposit. N2-Ar-He systematics studies and 3He/4He and δD-δ18O composition analyses show that the ore-forming fluid of the deposit is composed mainly of formation water (sedimentary brine) but not of meteoric water, which was thought to be source of the ore-forming fluid by most previous researchers. The content of mantle-derived magmatic water in the ore-forming fluid is quite low, usually lower than 10%. According to the source of the ore-forming fluid, the Changkeng Au-Ag deposit should belong to sedimentary brine transformed deposits. From the Late Jurassic to the Early Cretaceous Period, with deposition and accumulation of thick sediments in Sanzhou Basin, the formation water in the sedimentary layers was expelled from the basin because of overburden pressure and increasing temperature. The expelled fluid moved laterally along sedimentary layers to the margin of the basin, and finally moved upward along a gently-dipping in

  1. A Study on the Ore-forming Effect of Mantle-derived Fluid

    Institute of Scientific and Technical Information of China (English)

    Meng Qingqiang; Wu Jianfeng; Zhang Liuping

    2007-01-01

    Based on summarizing of the effect of mantle-derived fluid on the formation of ores, especially on gold ore,and with the latest investigations, such as the formation of ore from the action of shallow-deep fluid, the transportation effect of the thermal energy by mantle-derived fluid, this paper mainly aims at the effect of mantle-derived fluid on the generation of hydrocarbons. With the proof from geochemistry and fluid inclusion, it was suggested that the mantle-derived fluid not only supplied source materials for hydrocarbons, but also supplied essential energy and matter necessary for the generation of hydrocarbons. The mantle-derived fluid had a good effect, but at the same time it had an adverse effect under specific conditions, on the formation of reservoirs. This paper also discusses the future direction and significance of studying mantle-derived fluid.

  2. Geology and ore fluid geochemistry of the Jinduicheng porphyry molybdenum deposit, East Qinling, China

    Science.gov (United States)

    Li, Hongying; Ye, Huishou; Wang, Xiaoxia; Yang, Lei; Wang, Xiuyuan

    2014-01-01

    Jinduicheng deposit is a giant Mesozoic porphyry Mo system deposit in the East Qinling molybdenum belt, Shaanxi Province, China. The mineralization is associated with the I-type Jinduicheng granite porphyry. Both the porphyry stock and country rocks underwent intense hydrothermal alteration. The alteration, with increasing distance from the parent intrusion, changes from silicification, through potassic and phyllic assemblages, carbonation, to propylitic assemblages. Molybdenite, the dominant ore mineral, occurs in veinlets, most of which are hosted by the altered country rocks, with less than 25% of the ore in the porphyry body. The hydrothermal system comprises four stages, including pre-ore quartz and K-feldspar; two ore stages of quartz, K-feldspar, molybdenite, and Pb- And Zn-bearing sulfides; and post-ore quartz and carbonate. Six main types of primary fluid inclusions are present in hydrothermal quartz, including two-phase aqueous, one-phase aqueous, three-phase CO2-bearing, CO2-dominated fluid inclusions, gas inclusions, and melt inclusions. The homogenization temperatures of fluid inclusions range from 210 to 290 °C in the pre-ore stage, 150-310 °C in ore stage I, 150-360 °C in the ore stage II, and 195-325 °C in the post-ore stage quartz. Estimated salinities of the ore-forming fluids range from 6.9 to 13.5, 4.3 to 12.3, 6.2 to 12.4, and 3.4 to 9.9 wt.% NaCl equiv. in stages 1-4, respectively. The δ34S values of pyrite in the two ore stages range from 2.8‰ to 4.3‰, whereas the δ34S values of molybdenite range from 2.9‰ to 6.2‰. The data suggest both magmatic and crustal sources of sulfur. The δD and δ18O values for the hydrothermal fluids are -57.2‰ to -84.4‰ and 8.0‰ to -3.2‰, respectively. The fluid inclusion and stable data indicate that the pre-ore hydrothermal fluids were mostly of magmatic origin, but the fluids responsible for ore deposition were mixed magmatic and meteoric, and eventually meteoric water dominated the system

  3. Ore-forming material sources of the Baiyangping Cu-Co-Ag polymetallic deposit in the Lanping Basin, western Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    LI Zhiming; LIU Jiajun; ZHANG Changjiang

    2008-01-01

    The ore-forming material sources of the Baiyangping copper-cobalt-silver polymetallic deposit have been studied in view of the S, Pb, C, O and H isotopic characteristics and the ratio of Co/Ni of cohaltite. The results showed that sulfur in metallic sulfides may have come from a mixed sulfur-source consisting of the sulfur-source from metamorphic rocks in the basin basement with basic volcanic rocks and the sulfur-source from basin sulfates;lead in the ores was provided by the sedimentary rocks and basement rocks; CO2 in ore-forming fluids was derived from thermolysis of altered and normal marine facies carbonates and decarboxylation of sedimentary organic matter respectively; the ore-forming fluids belong to the SO4-Cl-Na-Ca-type basin thermal brines derived from paleo-meteoric waters; cobalt in the deposit may also be derived from the metamorphic rocks in the basin basement with basic volcanic rocks.

  4. Ore-forming fluid and mineralization of Caijiaying and Dajing polymetallic ore deposits

    Institute of Scientific and Technical Information of China (English)

    WANG; Lijuan; WANG; Jingbin; WANG; Yuwang; ZHU; Heping

    2004-01-01

    Fluid inclusions from the Dajing and Caijiaying deposits have nearly the same homogenization temperature. Correlation between temperature and salinity shows that both Sn- and Cu-bearing fluids Sn and Cu were present in the Dajing deposit but only one kind of fluids continuously evolved in the Caijiaying deposit. Study on rare earth elements (REE) in ancient fluid from the inclusions indicates that the fluid of Sn mineralizing stage in Dajing was derived from remelting magma of the continental crust, and the fluid of Cu-Pb-Zn mineralizing stage in the Dajing deposit and the fluid of Cu-Pb-Zn mineralization in the Caijiaying deposit were derived from the mantle. It is concluded that the Cu-Pb-Zn mineralizations in the Dajing and Caijiaying deposits resulted from the identical tectono-thermal event of magma-fluids induced by Mesozoic tectonic transition and extension in the eastern part of North China Craton.

  5. Clay minerals in uraniferous deposit of Imouraren (Tim Mersoi basin, Niger): implications on genesis of deposit and on ore treatment process

    International Nuclear Information System (INIS)

    Nigerian uraniferous deposits are located in carboniferous and Jurassic formations of Tim Mersoi basin. AREVA is shareholder of 3 mine sites in this area: SOMAIR and COMINAK, both in exploitation since 1960's and IMOURAREN, 80 km further South, whose exploitation is planned for 2015. Mineralization of Imouraren deposit is included in the fluvial formation of Tchirezrine 2 (Jurassic), composed of channels and flood plains. Facies of channel in-fillings range from coarse sandstones to siltstones, while overflow facies are composed of analcimolites. Secondary mineralogy was acquired during 2 stages: 1- diagenesis, with formation of clay minerals, analcime, secondary quartz and albites, and 2- stage of fluids circulations, which induced alteration of detrital and diagenetic minerals, formation of new phases and uranium deposition. A mineralogical zoning, at the scale of deposit resulted from this alteration. The heterogeneity of Tchirezrine 2, at the level of both facies and mineralogy, is also evidenced during ore treatment, as ore reacts differently depending on its source, with sometimes problems of U recovery. Ore treatment tests showed that analcimes and chlorites were both penalizing minerals, because of 1- the sequestration of U-bearing minerals into analcimes, 2- their dissolution which trends to move away from U solubilization conditions (pH and Eh) and to form numerous sulfates, and 3- problems of percolation. A detection method of analcime-rich ores, based on infrared spectroscopy, was developed in order to optimize ore blending and so to reduce negative effects during ore treatment process. (author)

  6. Fluid-solid interaction model for hydraulic reciprocating O-ring seals

    Science.gov (United States)

    Liao, Chuanjun; Huang, Weifeng; Wang, Yuming; Suo, Shuangfu; Liu, Ying

    2013-01-01

    Elastohydrodynamic lubrication characteristics of hydraulic reciprocating seals have significant effects on sealing and tribology performances of hydraulic actuators, especially in high parameter hydraulic systems. Only elastic deformations of hydraulic reciprocating seals were discussed, and hydrodynamic effects were neglected in many studies. The physical process of the fluid-solid interaction effect did not be clearly presented in the existing fluid-solid interaction models for hydraulic reciprocating O-ring seals, and few of these models had been simultaneously validated through experiments. By exploring the physical process of the fluid-solid interaction effect of the hydraulic reciprocating O-ring seal, a numerical fluid-solid interaction model consisting of fluid lubrication, contact mechanics, asperity contact and elastic deformation analyses is constructed with an iterative procedure. With the SRV friction and wear tester, the experiments are performed to investigate the elastohydrodynamic lubrication characteristics of the O-ring seal. The regularity of the friction coefficient varying with the speed of reciprocating motion is obtained in the mixed lubrication condition. The experimental result is used to validate the fluid-solid interaction model. Based on the model, The elastohydrodynamic lubrication characteristics of the hydraulic reciprocating O-ring seal are presented respectively in the dry friction, mixed lubrication and full film lubrication conditions, including of the contact pressure, film thickness, friction coefficient, liquid film pressure and viscous shear stress in the sealing zone. The proposed numerical fluid-solid interaction model can be effectively used to analyze the operation characteristics of the hydraulic reciprocating O-ring seal, and can also be widely used to study other hydraulic reciprocating seals.

  7. Messinian Salinity Crisis and basin fluid flow

    Science.gov (United States)

    Bertoni, Claudia; Cartwight, Joe

    2014-05-01

    Syn- and post-depositional movement of fluids through sediments is one of the least understood aspects in the evolution of a basin. The conventional hydrostratigraphic view on marine sedimentary basins assumes that compactional and meteoric groundwater fluid circulation drives fluid movement and defines its timing. However, in the past few years, several examples of instantaneous and catastrophic release of fluids have been observed even through low-permeability sediments. A particularly complex case-study involves the presence of giant salt bodies in the depocentres of marine basins. Evaporites dramatically change the hydrostratigraphy and fluid-dynamics of the basin, and influence the P/T regimes, e.g. through changes in the geothermal gradient and in the compaction of underlying sediments. Our paper reviews the impact of the Messinian Salinity Crisis (MSC) and evaporites on fluid flow in the Mediterranean sub-basins. The analysis of geological and geophysical sub-surface data provides examples from this basin, and the comparison with analogues in other well-known evaporitic provinces. During the MSC, massive sea-level changes occurred in a relatively limited time interval, and affected the balance of fluid dynamics, e.g. with sudden release or unusual trapping of fluids. Fluid expulsion events are here analysed and classified in relation to the long and short-term effects of the MSC. Our main aim is to build a framework for the correct identification of the fluid flow-related events, and their genetic mechanisms. On basin margins, where evaporites are thin or absent, the sea-level changes associated with the MSC force a rapid basinward shift of the mixing zone of meteoric/gravity flow and saline/compactional flow, 100s-km away from its pre-MSC position. This phenomenon changes the geometry of converging flows, creates hydraulic traps for fluids, and triggers specific diagenetic reactions in pre-MSC deep marine sediments. In basin-centre settings, unloading and

  8. Characteristics of the ore forming fluid from the zinc poly-metallic deposit in the Mopan mine area, Guangxi Nandan

    Institute of Scientific and Technical Information of China (English)

    Ou Zheng; Wei Chongtao; Luo Jun; Bao Yuan; Santigie Kekuda Sesay

    2012-01-01

    Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy.Further studies were conducted on the nature and source of the ore forming fluid and on the mechanism of deposit formation.The results show that there are three types of inclusions that occur in both the layered and veined ore body.These are liquid inclusions,CO2 inclusions with a liquid phase,and NaCl-H2O multiphase inclusions.The fluid inclusions in both the layered and veined ore bodies have similar characteristics.The ore forming fluid is strongly reducing,was exposed to low to medium temperatures,salinity,and pressures.The source of this ore forming fluid was a mix of submarine volcanic spring (blow-piping),magmatic hydrothermal jet,and underground water.

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

    Science.gov (United States)

    Hofstra, Albert H.; Landis, Gary P.

    2012-01-01

    38Ar produced by nucleogenic production from 41K. In contrast, some ore and gangue minerals yield significant SO2 and have low RH and RS values of a more oxidized fluid. Three extracts from gangue quartz have high helium R/RA values indicative of a mantle source and neon isotope compositions that require nucleogenic production of 22Ne in fluorite from U ± Th decay. Two extracts from gangue quartz have estimated 40K/40Ar that permit a Precambrian age. Extracts from gangue quartz in three different ore zones are biased toward the hypersaline population of inclusions and have a tight range of ion ratios (Na, K, NH4, Cl, Br, F) suggestive of a single fluid. Their Na, Cl, Br ratios suggest this fluid was a mixture of magmatic and basinal brine. Na-K-Ca temperatures (279°-347°C) are similar to homogenization temperatures of hypersaline inclusions. The high K/Na of the brine may be due to albitization of K silicate minerals in country rocks. Influx of K-rich brines is consistent with the K metasomatism necessary to form gangue biotite with high Cl. An extract from a post-ore quartz vein is distinct and has Na, Cl, Br ratios that resemble metamorphic fluids in Cretaceous silver veins of the Coeur d'Alene district in the Belt Basin. The results show that in some samples, for certain components, it is possible to "see through" the Cretaceous metamorphic overprint. Of great import for genetic models, the volatiles trapped in gangue quartz have 3He derived from a mantle source and 22Ne derived from fluorite, both of which may be attributed to nearby ~1377 Ma basalt-rhyolite magmatism. The brine trapped in gangue quartz is a mixture of magmatic fluid and evaporated seawater. The former requires a granitic intrusion that is present in the bimodal intrusive complex, and the latter equatorial paleolatitudes that existed in the Mesoproterozoic. The results permit genetic models involving heat and fluids from the neighboring bimodal plutonic complex and convection of basinal brine

  10. Hydrocarbon accumulation in deep fluid modified carbonate rock in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The activities of deep fluid are regionalized in the Tarim Basin. By analyzing the REE in core samples and crude oil, carbon isotope of carbon dioxide and inclusion temperature measurement in the west of the Tazhong Uplift in the western Tarim Basin, all the evidence confirms the existence of deep fluid. The deep fluid below the basin floor moved up into the basin through discordogenic fauit and volcanicity to cause corrosion and metaaomatosis of carbonate rock by exchange of matter and energy. The pore structure and permeability of the carbonate reservoirs were improved, making the carbonate reservoirs an excellent type of deeply buried modification. The fluorite ore belts discovered along the large fault and the volcanic area in the west of the Tazhong Uplift are the outcome of deep fluid action. Such carbonate reservoirs are the main type of reservoirs in the Tazhong 45 oilfield. The carbonate reservoirs in well YM 7 are improved obviously by thermal fluid dolomitization. The origin and territory of deep fluid are associated with the discordogenic fault and volcanicity in the basin. The discordogenic fault and volcanic area may be the pointer of looking for the deep fluid modified reservoirs. The primary characteristics of hydrocarbon accumulation in deep fluid reconstructed carbonate rock are summarized as accumulation near the large fault and volcano passage, late-period hydrocarbon accumulation after volcanic activity, and subtle trap reservoirs controlled by lithology.

  11. Territorial pattern and classification of soils of Kryvyi Rih Iron-Ore Basin

    OpenAIRE

    О. О. Dolina; О. М. Smetana

    2014-01-01

    The authors developed the classification of soils and adapted it to the conditions of Krivyi Rih industrial region. It became the basis for determining the degree of soil cover transformation in the iron-ore basin under technogenesis. The classification represents the system of hierarchical objects of different taxonomic levels. It allows determination of relationships between objects and their properties. Researched patterns of soil cover structures’ distribution were the basis for the relev...

  12. 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

    Science.gov (United States)

    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

  13. Ore-forming fluid and metallization of the Huanggangliang skarn Fe-Sn deposit, Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Two kinds of inclusions, fluid-melting inclusion and gas-liquid inclusion, are present in the Huanggangliang deposit in eastern Inner Mongolia. Temperature ranges from 1050℃ of fluid-melting inclusion to 150℃ of liquid inclusion. Away from intrusion, the inclusions of orebodies in-tend to be characterized by simpler type, lower temperature and lower salinity, as well as weakened relation to intrusion. The metallization of the Huanggangliang deposit is characterized by multiple activities of ore-forming fluid, multi-source, multi-stage accumulation of ore-forming material, F-rich environment, enrichment of F, organic gas, CO2 and N2, and involving of residual magma.

  14. Numerical Modeling of Multiphase Fluid Flow in Ore-Forming Hydrothermal Systems

    Science.gov (United States)

    Weis, P.; Driesner, T.; Coumou, D.; Heinrich, C. A.

    2007-12-01

    Two coexisting fluid phases - a variably saline liquid and a vapor phase - are ubiquitous in ore-forming and other hydrothermal systems. Understanding the dynamics of phase separation and the distinct physical and chemical evolution of the two fluids probably plays a key role in generating different ore deposit types, e.g. porphyry type, high and low sulfidation Cu-Mo-Au deposits. To this end, processes within hydrothermal systems have been studied with a refined numerical model describing fluid flow in transient porous media (CSP~5.0). The model is formulated on a mass, energy and momentum conserving finite-element-finite-volume (FEFV) scheme and is capable of simulating multiphase flow of NaCl-H20 fluids. Fluid properties are computed from an improved equation of state (SOWAT~2.0). It covers conditions with temperatures of up to 1000 degrees~C, pressures of up to 500 MPa, and fluid salinities of 0~to 100%~NaCl. In particular, the new set-up allows for a more accurate description of fluid phase separation during boiling of hydrothermal fluids into a vapor and a brine phase. The geometric flexibility of the FEFV-meshes allows for investigations of a large variety of geological settings, ranging from ore-forming processes in magmatic hydrothermal system to the dynamics of black smokers at mid-ocean ridges. Simulations demonstrated that hydrothermal convection patterns above cooling plutons are primarily controlled by the system-scale permeability structure. In porphyry systems, high fluid pressures develop in a stock rising from the magma chamber which can lead to rock failure and, eventually, an increase in permeability due to hydrofracturing. Comparisons of the thermal evolution as inferred from modeling studies with data from fluid inclusion studies of the Pb-Zn deposits of Madan, Bulgaria are in a strikingly good agreement. This indicates that cross-comparisons of field observations, analytical data and numerical simulations will become a powerful tool towards a

  15. Geothermal fluid genesis in the Great Basin

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, T.; Buchanan, P.K.

    1990-01-01

    Early theories concerning geothermal recharge in the Great Basin implied recharge was by recent precipitation. Physical, chemical, and isotopic differences between thermal and non-thermal fluids and global paleoclimatic indicators suggest that recharge occurred during the late Pleistocene. Polar region isotopic studies demonstrate that a depletion in stable light-isotopes of precipitation existed during the late Pleistocene due to the colder, wetter climate. Isotopic analysis of calcite veins and packrat midden megafossils confirm the depletion event occurred in the Great Basin. Isotopic analysis of non-thermal springs is utilized as a proxy for local recent precipitation. Contoured plots of deuterium concentrations from non-thermal and thermal water show a regional, systematic variation. Subtracting contoured plots of non-thermal water from plots of thermal water reveals that thermal waters on a regional scale are generally isotopically more depleted. Isolated areas where thermal water is more enriched than non-thermal water correspond to locations of pluvial Lakes Lahontan and Bonneville, suggesting isotopically enriched lake water contributed to fluid recharge. These anomalous waters also contain high concentrations of sodium chloride, boron, and other dissolved species suggestive of evaporative enrichment. Carbon-age date and isotopic data from Great Basin thermal waters correlate with the polar paleoclimate studies. Recharge occurred along range bounding faults. 151 refs., 62 figs., 15 tabs.

  16. Sources of ore-forming fluids and metallic materials in the Jinwozi lode gold deposit, eastern Tianshan Mountains of China

    Institute of Scientific and Technical Information of China (English)

    LIU; Wei(刘伟); LI; Xinjun(李新俊); DENG; Jun(邓军)

    2003-01-01

    This paper presents gas compositions and H-, O-isotope compositions of sulfide- and quartz-hosted fluid inclusions, and S-, Pb-isotope compositions of sulfide separates collected from the principal Stage 2 ores in Veins 3 and 210 of the Jinwozi lode gold deposit, eastern Tianshan Mountains of China. Fluid inclusions trapped in quartz and sphalerite are dominantly primary. H- and O-isotopic compositions of pyrite-hosted fluid inclusions indicate two major contributions to the ore-forming fluid that include the degassed magma and the meteoric-derived but rock 18O-buffered groundwater. However, H- and O-isotopic compositions of quartz-hosted fluid inclusions essentially suggest the presence of groundwater. Sulfide-hosted fluid inclusions show considerably higher abundances of gaseous species CO2, N2, H2S, etc. Than quartz-hosted ones. The linear trends among inclusion gaseous species reflect the mixing tendency between the gas-rich magmatic fluid and the groundwater. The relative enrichment of gaseous species in sulfide-hosted fluid inclusions, coupled with the banded ore structure indicating alternate precipitation of quartz with sulfide minerals, suggests that the magmatic fluid has been inputted to the ore-forming fluid in pulsation. Sulfur and lead isotope compositions of pyrite and galena separates indicate an essential magma derivation for sulfur but the multiple sources for metallic materials from the mantle to the bulk crust.

  17. Release of beryllium from mineral ores in artificial lung and skin surface fluids.

    Science.gov (United States)

    Duling, Matthew G; Stefaniak, Aleksandr B; Lawrence, Robert B; Chipera, Steve J; Virji, M Abbas

    2012-06-01

    Exposure to some manufactured beryllium compounds via skin contact or inhalation can cause sensitization. A portion of sensitized persons who inhale beryllium may develop chronic beryllium disease (CBD). Little is understood about exposures to naturally occurring beryllium minerals. The purpose of this study was to assess the bioaccessibility of beryllium from bertrandite ore. Dissolution of bertrandite from two mine pits (Monitor and Blue Chalk) was evaluated for both the dermal and inhalation exposure pathways by determining bioaccessibility in artificial sweat (pH 5.3 and pH 6.5), airway lining fluid (SUF, pH 7.3), and alveolar macrophage phagolysosomal fluid (PSF, pH 4.5). Significantly more beryllium was released from Monitor pit ore than Blue Chalk pit ore in artificial sweat buffered to pH 5.3 (0.88 ± 0.01% vs. 0.36 ± 0.00%) and pH 6.5 (0.09 ± 0.00% vs. 0.03 ± 0.01%). Rates of beryllium released from the ores in artificial sweat were faster than previously measured for manufactured forms of beryllium (e.g., beryllium oxide), known to induce sensitization in mice. In SUF, levels of beryllium were below the analytical limit of detection. In PSF, beryllium dissolution was biphasic (initial rapid diffusion followed by latter slower surface reactions). During the latter phase, dissolution half-times were 1,400 to 2,000 days, and rate constants were ~7 × 10(-10) g/(cm(2)·day), indicating that bertrandite is persistent in the lung. These data indicate that it is prudent to control skin and inhalation exposures to bertrandite dusts. PMID:21866318

  18. Territorial pattern and classification of soils of Kryvyi Rih Iron-Ore Basin

    Directory of Open Access Journals (Sweden)

    О. О. Dolina

    2014-10-01

    Full Text Available The authors developed the classification of soils and adapted it to the conditions of Krivyi Rih industrial region. It became the basis for determining the degree of soil cover transformation in the iron-ore basin under technogenesis. The classification represents the system of hierarchical objects of different taxonomic levels. It allows determination of relationships between objects and their properties. Researched patterns of soil cover structures’ distribution were the basis for the relevant mapping and classification of soils. The classification is adapted to highly-influential industrial conditions of soils formation in the region. The adaptation measures were specific classification levels and units, which provided more detailed differentiation of soils. The authors proposed to separate the soils by the degree of soil formation potential realization for super-divisions. The potential determination allowed predicting the outcome of soil formation and identification of transformation degree of soil cover structures in the region. The results indicated that the main type of soil structures in the industrial region was represented by primitive soils (indicated as a separate type. These soils were determined as dynamic elements in the structure of industrial region soil cover. The article indicated that presence of soil cover structures with the domination of technogenic soils, particularly post-technogenic soils, was the marker of the soil cover in Krivyi Rih Iron-Ore Basin

  19. Cenozoic evolution of tectono-fluid and metallogenic process in Lanping Basin,western Yunnan Province, Southwest China: Constraints from apatite fission track data

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoming; SONG Yougui

    2006-01-01

    Since the Mesozoic, abundant metal and salt deposits have been formed in the Lanping Basin, western Yunnan Province, Southwest China, constituting a well-known hydrothermal ore belt in China. Most of the deposits are meso-epithermal hydrothermal deposits. This paper preliminarily deals with the mineralization ages of hydrothermal deposits in the Lanping Basin by using the apatite fission track method, and integrates the spatial distribution of the deposits and their regional geological backgrounds, to give the preliminary viewpoints as follows: (1) the apatite fission track ages acquired range from 19.9 Ma to 52.8 Ma, much younger than those of their host strata, so they may be considered to be mineralization ages, which represent the late mineralization period; (2) the apatite fission track ages tend to become younger from the west to the middle of the basin, indicating that the latest evolution of tectono-fluid and/or metallogenic processes of the middle basin ended later than that in the west; (3) in the Paleogene, most of the Cu deposits were formed in the western part of the basin; (4) the major metallogenic processes occur between the Paleogene and the Neogene, because the eastern and western edges of the basin were subducted into and collided with its bilateral continental blocks, respectively, and the central fault was strongly activated, which led to the processes of large-scale ore-forming fluids, and their differentiation and transport because of the variation of their physical and chemical properties. Having been squeezed and uplifted, the Lanping Basin became an intermontane basin that contains many kinds of fluid traps resulting in the formation of different types of ore deposits (for example, Pb-Zn, Cu, Ag) of different scales in the middle of the basin. Simultaneously, the fluids with volatile elements such as Hg, Sb and As were transported upwards along the central fault system and diffused into its subordinate fractures, thus leading to the

  20. Ore-forming fluid constraints on illite crystallinity (IC) at Dexing porphyry copper deposit, Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Illite, a distinctive kind of clay minerals of potassiumalteration within the hydrothermal alteration zone, frequently occurs at the Tongchang porphyry copper deposit ore field. The illite crystallinity (IC) value and expandability are mainly affected by water/rock ratio or fluid flux. It was formed by illitization of plagioclase and micas during hydrothermal fluid-rock interaction within the porphyry body and near the contact zone with wall rocks. Moreover, the negative correlation between illite index (IC) and copper grade indicates that within the alteration zone, the smaller the illite crystallinity value, the higher the alteration degree, and the higher the copper grade due to higher water/rock ratio. At lower levels of the porphyry body, however, the illite crystallinity (IC) values are mainly controlled by temperature and time duration.

  1. Discussion on ore-controlling factors and metallogenic model of uranium ore-formation in Xieersu depression, south Songliao Basin

    International Nuclear Information System (INIS)

    Based on the geologic characteristics of Xieersu depression, uranium mineralization in this area is believed to be sandstone type of epigenic of multi times superimposition and the ore-formation is mainly controlled by the factors such as the uranium source, the development of interlayer oxidation zone, the variation of hydrodynamic conditions, etc.. A preliminary metallogenetic model has been set up. (authors)

  2. Ore formation at the Kupol epithermal gold-silver deposit in northeastern Russia deduced from fluid inclusion study

    Science.gov (United States)

    Volkov, A. V.; Prokof'ev, V. Yu.; Savva, N. E.; Sidorov, A. A.; Bayankin, M. A.; Uyutnov, K. V.; Kolova, E. E.

    2012-07-01

    The Kupol epithermal gold-silver deposit-the largest of this type of mineralization in northeastern Russia-is situated in the outer zone of the Okhotsk-Chukotka volcanic belt. The results of thermobarogeochemical study of fluid inclusions in quartz from ore veins at the Kupol deposit are compared with the data on the Dvoinoi and Arykvaam deposits. The study of aqueous extracts from fluid inclusions revealed that the chemical compositions of ore-forming fluids at the Dvoinoi and Kupol deposits are similar in most elements. The only substantial difference is that fluids from the Kupol deposit are considerably enriched in sulfate, as is characteristic of the alunite-subtype of epithermal high-sulfidation mineralization. The salinity of aqueous solutions filling inclusions in amethyst and quartz from ore veins at the Kupol and Dvoinoi deposits is two-three times higher than the salinity of fluid inclusions from the barren veins at the Arykvaam occurrence. The data obtained support the hypothesis put forward earlier that fumaroles and solfataras played a part in ore deposition at the Kupol deposit.

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

    Science.gov (United States)

    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

  4. Helium and argon isotope trace in ore-forming fluid of Sawuer gold belt in Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    SHEN Ping; SHEN Yuanchao; ZENG Qingdong; LIU Tiebing; LI Guangming

    2004-01-01

    The helium and argon isotope compositions of fluid inclusions hosted in pyrite have been measured from Kuoerzhenkuola and Buerkesidai gold deposits in Sawuer gold belt, northern Xinjiang. The results show that fluidinclusion 3He/4He ratios are 0.64 Ra-4.25 Ra and 1.16 Ra 9.48 Ra, 40Ar/36Ar ratios are 282-359 and 312-525 for Kuoerzhenkuola and Buerkesidai gold deposits respectively.The ore-forming fluids of two deposits possessed the same source and derived mainly from mantle beneath the island arc (including oceanic crust and oceanic sediments by subduction of oceanic plate). They were diluted by incorporating meteoric water to form a mixture of mantle- and partial meteoric water-derived fluid. The ore-forming fluids of two deposits are of the same evolutionary histories. From the early to the late mineralization stages, the ratios of meteoric water/mantle- derived fluid in ore-forming fluid increased gradually. Based on these results and detailed geological and geochemical studies on the two deposits, it is proposed that the geneses of the two gold deposits are the same, being volcanogenic late-stage hydrothermal gold deposits occurring in the same volcanic apparatus.

  5. Ore-forming mechanism for the Xiaoxinancha Au-rich Cu deposit in Yanbian, Jilin Province, China: Evidence from noble gas isotope geochemistry of fluid inclusions in minerals

    Institute of Scientific and Technical Information of China (English)

    SUN JingGui; ZHAO JunKang; CHEN JunQiang; KEISUKE Nagao; HIROCHiKA Sumino; SHEN Kun; MEN LanJing; CHEN Lei

    2008-01-01

    The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and 40Ar/36Ar are in the ranges of 4.45-0.08 Ra, 10.2-8.8 and 306-430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123-102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition- crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as: (1

  6. Ore-forming Fluid Systems and Mineralization in the Eastern Jiangnan Uplift in the Border Area of Anhui and Jiangxi Provinces, China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Taofa; YUAN Feng; HOU Mingjin; FAn Yu; DU Jianguo; ZHU Guang; YUE Shucang

    2004-01-01

    Obvious differences in mineralization characteristics exist between the southern and northern parts of the eastern part of the Jiangnan Uplift in northern Jiangxi Province and southern Anhui Province. The regional metallogeny is discussed, and the ore-forming fluid systems are classified in this article. It is proposed that the fluid ore-forming activities in the Jiangnan Uplift both in northern Jiangxi and southern Anhui have close relationships with the crustmantle interaction and magmatic-tectonic activities. The types and scales of the mineralization on the both sides of the eastern Jiangnan Uplift were determined by fluid ore-forming systems and geological backgrounds.

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

    Science.gov (United States)

    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.

  8. Characteristics and evolution of ore-forming fluids of the Chongjiang copper deposit in the Gangdise porphyry copper belt, Tibet

    Institute of Scientific and Technical Information of China (English)

    Yuling Xie; Jiuhua Xu; Guangming Li; Zhiming Yang; Longsheng Yi

    2007-01-01

    Petrography, microthermometry, and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) studies were performed on the fluid inclusions in the ore-bearing quartz veins and quartz phenocrysts in the porphyry of the Chongjiang porphyry copper deposit. The analyses of the fluid inclusions indicate that the ore-forming fluids were exsolved from magma. They are near-saturated, supercritical, rich in volatile constituents, and have the capture temperature of 362-389°C and salinities of 17.7wt%-18.9wt% NaCl eq. With the decreasing of temperature and pressure, the supercritical fluids were separated into a low salinity vapor phase and a high salinity liquid phase. During quartz-sericitization, the high salinity fluid boiled and separated into a low salinity vapor phase and a high salinity liquid phase. The high salinity inclusions that formed in the boiling process had daughter mineral melting temperatures higher than the homogenization temperatures of the vapor and liquid phases. The late fluids that are responsible for argillization are of lower temperature and salinity.

  9. Fluid mixing as the mechanism of formation of the Dajing Cu-Sn-Ag-Pb-Zn ore deposit, Inner Mongolia--Fluid inclusion and stable isotope evidence

    Institute of Scientific and Technical Information of China (English)

    LIU; Wei(刘伟); LI; Xinjun(李新俊); TAN; Jun(谭骏)

    2003-01-01

    Dajing Cu-Sn-Ag-Pb-Zn ore deposit, in the Inner Mongolia Autonomous Region of China, is a fissure-filling hydrothermal ore deposit. The δD values of quartz-hosted inclusion water are centered at -100‰ - -130‰. Theδ34S values of sulfide ore minerals andδ13C values of carbonate gangue minerals vary from -0.3‰ to 2.6‰ and from -2.9‰ to -7.0‰, respectively. Integrated isotopic data point to two major contributions to the mineralizing fluid that include a dominant meteoric-derived groundwater, and sulfur and carbon species from hypogene magma. Linear trends are exhibited on the gaseous H2O versus CO2 plot, and plots of CO, N2, CH4, and C2H6. It is shown by quantitative simulation that magma degassing cannot explain the linear trends. Hence, these linear trends are interpreted in terms of mixing of CO2-rich magmatic fluid with meteoric-derived groundwater. The groundwater circulated in Paleozoic sedimentary rocks and absorbed CO, N2, CH4, C2H6 and radiogenic Ar from organic matter. Cooling effects resulting from mixing have caused the precipitation of ore minerals.

  10. Syntectonic fluid flow and fluid compartmentalization in a compressive basin: Example of the Jaca basin (Southwest Pyrenees, Spain)

    Science.gov (United States)

    Lacroix, Brice; Travé, Anna; Buatier, Martine; Labaume, Pierre

    2013-04-01

    During compressive events, deformation in sedimentary basins is mainly accommodated by thrust faults emplacement and related fold growth. In such a structure, thrust faults are generally rooted in the basement and may act as conduits or barriers for crustal fluid flow. However, most of recent studies suggest that fluid flow through such discontinuities is not so evident and depends on the structural levels of the thrust inside the fold-and-thrust belt. In order to constrain the paleofluid flow through the Jaca thrust-sheet-top basin (Paleogene southwest-Pyrenean fold-and-thrust belt) we focus our study on different thrust faults located at different structural levels. The microstructures observed in the different studied fault zones are similar and consist of pervasive cleavage, calcite shear and extension veins and late dilatation veins. In order to constrain the nature and the source of fluids involved in fluid-rock interactions in fault zones, a geochemical approach, based on oxygen and carbon stable isotopes and trace elements on calcite, was adopted on the different vein generations and host rocks. The results suggest a high complexity in the paleo-hydrological behaviors of thrust faults evidencing a fluid-flow compartmentalization of the basin. North of the Jaca basin, previous studies in the southern part of the Axial Zones showed the contribution of deep metamorphic water, probably derived from the Paleozoic basement, along along fault zones related the major Gavarnie thrust. Contrarily, in the northern part of the Jaca basin, we evidence the contribution of formation water during the Monte Perdido thrust fault activity. These data suggest a closed hydrological fluid system where distance of fluid flow did not exceeded 70 m. On the other hand, the Jaca and Cotiella thrust faults, both located more to the south in the basin, are characterized by a composite fluid flow system. Indeed, stable isotopes and trace elements compositions of the first generation of

  11. Ore-forming fluids in the Dongping gold deposit, northwestern Hebei Province

    Institute of Scientific and Technical Information of China (English)

    FAN; Hongrui

    2001-01-01

    : 1435-1444.[11]Schwartz, M. O., Determining phase volumes of mixed CO2-H2O inclusions using microthermometric measurements, Mineral Deposita, 1989, 24: 43-47.[12]Brown, P. E., Hagemann, S. G., MacFlincor and its application to fluids in Archean lode-gold deposits, Geochimica et Cosmochimica Acta, 1995, 59: 3943-3952.[13]Fan Hongrui, Xie Yihan, Zhao Rui et al., Dual origins of Xiaoqinling gold-bearing quartz veins: Fluid inclusion evidences, Chinese Science Bulletin, 2000, 45(15): 1424-1430.[14]Chen Yanjing, Li Chao, Zhang Jing et al., Sr and O isotopic characteristics of porphyries in the Qinling molybdenum de-posit belt and their implication to genetic mechanism and type, Science in China, Ser. D, 2000, 43 (supp.): 82-94.[15]Zhang Fuxin, Chen Yanjing, Li Chao et al., Geological and geochemical character and genesis of the Jinlongshan-Qiuling gold deposits in Qinling orogen: Metallogenic mechanism of the Qinling-pattern Carlin-type gold deposits, Science in China, Ser. D, 2000, 43(supp.): 95-107.[16]Chen Yanjing, Guo Guangjun, Li Xin, Metallogenic geodynamic background of gold deposits in Granite-greenstone ter-rains of North China craton, Science in China Ser. D, 1998, 41(2): 113-120.[17]Clayton, R. N., Oxygen isotope exchange between quartz and water, J. Geophys. Res., 1972, 77: 3057-3607.[18]Zhang Ligang, Cheng Zhengshen, Liu Jingxiu et al., Two Stage Water-rock Interaction and Prospecting Cases, Beijing: Geological Publishing House, 1995, 1-231.[19]Jiang Sihong, Nie Fengjun, 40Ar-39Ar geochronology of the Shuiquangou alkaline complex and related gold deposits, Northwestern Hebei, China, Geological Review, 2000, 46(6): 621-627.[20]Taylor, H. P., Oxygen and hydrogen isotope relationships, in Barnes H L(ed.), Geochemistry of Hydrothermal Ore Depos-its, 2nd ed., New York: John Wiley & Sons, 1979, 236-277.[21]Yardley, B. W. D., Post-metamorphic gold-quartz veins from N.W Italy: The composition and origin of the ore fluid, Min

  12. Analysis on uranium ore-formation conditions and prospecting direction of Wulanchabu depression in Erlian basin

    International Nuclear Information System (INIS)

    Through the analysis of uranium source conditions, deposition-tectonic evolution and the characteristics of uranium ore forming in Wulanchabu depression, conclusions are drawn as follows: Wulanchabu depression has favorable ore-forming geology conditions; sandstone-type uranium deposit should be searched in the valley of Saihan formation 'Zhurihe-Qiharigetu-Saihangaobi' in the east of Wulanchabu depression; syndeposition-epigenic alteration type uranium deposits can be exploited in Erlian formation of Erenzuoer north of the depression, and syndepositional type uranium deposit may lies in Naomugen formation of Chagan-Naomugen-Wulanhuxiu zone in the northwest of the depression. (authors)

  13. Sedimentary basin geochemistry and fluid/rock interactions workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-12-31

    Fundamental research related to organic geochemistry, fluid-rock interactions, and the processes by which fluids migrate through basins has long been a part of the U.S. Department of Energy Geosciences program. Objectives of this program were to emphasize those principles and processes which would be applicable to a wide range of problems associated with petroleum discovery, occurrence and extraction, waste disposal of all kinds, and environmental management. To gain a better understanding of the progress being made in understanding basinal fluids, their geochemistry and movement, and related research, and to enhance communication and interaction between principal investigators and DOE and other Federal program managers interested in this topic, this workshop was organized by the School of Geology and Geophysics and held in Norman, Oklahoma in November, 1991.

  14. Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia

    International Nuclear Information System (INIS)

    The Cleo gold deposit, 55 km south of Laverton in the Eastern Goldfields Province of Western Australia, is characterised by banded iron-formation (BIF)-hosted ore zones in the gently dipping Sunrise Shear Zone and high-grade vein-hosted ore in the Western Lodes. There is evidence that gold mineralisation in the Western Lodes (which occurred at ca 2655 Ma) post-dates the majority of displacement along the Sunrise Shear Zone, but it remains uncertain if the ore in both structures formed simultaneously or separately. Overall, the Pb, Nd, Sr, C, O and S isotopic compositions of ore-related minerals from both the Western Lodes and ore zones in the Sunrise Shear Zone are similar. Early low-salinity aqueous-carbonic fluids and late high-salinity fluids with similar characteristics are trapped in inclusions in quartz veins from both the Sunrise Shear Zone and the Western Lodes. The early CO2, CO2-H2O, and H2O-dominant inclusions are interpreted as being related to ore formation, and to have formed from a single low-salinity aqueous-carbonic fluid as a result of intermittent fluid immiscibility. Homogenisation temperatures indicate that these inclusions were trapped at approximately 280 deg C and at approximately 4 km depth, in the deeper epizonal range. Differences between the ore zones are detected in the trace-element composition of gold samples, with gold from the Sunrise Shear Zone enriched in Ni, Pb, Sn, Te and Zn, and depleted in As, Bi, Cd, Cu and Sb, relative to gold from the Western Lodes Although there are differences in gold composition between the Sunrise Shear Zone and Western Lodes, and hence the metal content of ore fluids may have varied slightly between the different ore zones, no other systematic fluid or solute differences are detected between the ore zones. Given the fact that the ore fluids in each zone have very similar bulk properties, the considerable differences in gold grade, sulfide mineral abundance, and ore textures between the two ore zones

  15. Origin of gray-green sandstone in ore bed of sandstone type uranium deposit in north Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    LI; ZiYing; FANG; XiHeng; CHEN; AnPing; OU; GuangXi; XIAO; XinJian; SUN; Ye; LIU; ChiYang; WANG; Yi

    2007-01-01

    Dongsheng sandstone-type uranium deposit is located in the northern part of Ordos Basin, occurring in the transitional zones between gray-green and gray sandstones of Jurassic Zhiluo Formation. Sandstones in oxidized zone of the ore bed look gray-green, being of unique signature and different from one of ordinary inter-layered oxidation zone of sandstone-type uranium deposits. The character and origin of gray-green sandstones are systematically studied through their petrology, mineralogy and geochemistry. It is pointed out that this color of sandstones is originated from secondary oil-gas reduction processes after paleo-oxidation, being due to acicular-leaf chlorite covering surfaces of the sandstone grains. To find out the origin of gray-green sandstone and recognize paleo-oxidation zones in the ore bed are of not only theoretical significance for understanding metallogenesis of this kind of sandstone-type uranium deposit, but also very importantly practical significance for prospecting for similar kind of sandstone-type uranium deposit.

  16. Origin and evolution of ore-forming fluids in the Hemushan magnetite-apatite deposit, Anhui Province, Eastern China, and their metallogenic significance

    Science.gov (United States)

    Luo, Gan; Zhang, Zhiyu; Du, Yangsong; Pang, Zhenshan; Zhang, Yanwen; Jiang, Yongwei

    2015-12-01

    The Middle-Lower Yangtze River Metallogenic Belt in the northern Yangtze Block is one of the most important economic mineral districts in China. The Hemushan deposit is a medium-class Fe deposit located in the southern part of the Ningwu iron ore district of the Middle-Lower Yangtze River Metallogenic Belt. The Fe-orebodies are mainly hosted in the contact zone between diorite and Triassic marble. The actinolite-phlogopite-apatite-magnetite ore shows metasomatic/filling textures and disseminated/mesh-vein structures. Based on evidences and petrographic observations, the ore-forming process can be divided into three distinct periods-the early metallogenic period (albite-diopside stage), the middle metallogenic period (magnetite stage and hematite stage), and the late metallogenic period (quartz-pyrite stage and carbonate stage). Fluid inclusion studies show four types of inclusions: type I daughter mineral-bearing three-phase inclusions (L + V + S), type II vapor-rich two-phase inclusions (L + V), type III liquid-rich two phase inclusions (L + V), and minor type IV liquid-phase inclusions (L). Apatites from the magnetite stage contain type I, type II and type III inclusions; anhydrites from the hematite stage mainly contain abundant type II inclusions and relatively less type I inclusions; quartz and calcite from the late metallogenic stage are mainly characterized by type III inclusions. Laser Raman spectroscopy and microthermometry of fluid inclusions show that the ore-forming fluids broadly correspond to unsaturated NaCl-H2O system. From the magnetite stage to the carbonate stage, the ore-forming fluids evolved from moderate-high temperature (average 414 °C), moderate salinity (average 25.01 wt.% NaCl equiv.) conditions to low temperature (average 168 °C), low salinity (average 6.18 wt.% NaCl equiv.) conditions. Hydrogen and oxygen isotopic studies indicate that the ore-forming fluid during the early stage of middle metallogenic period was mainly of magmatic

  17. Ore Characteristics and Fluid Inclusion of the Base Metal Vein Deposit in Moncong Bincanai Area, Gowa, South Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Asmariyadi Asmariyadi

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v7i4.146This paper is dealing with ore characteristics and fluid inclusion of the Moncong Bincanai, Biringbulu Subregency of Gowa Regency, South Sulawesi Province, Indonesia. The mineralization is a vein type, with the orientation of N170oE /65oSW, hosted in open-space filling within basalt. The mineralization consists of galena, sphalerite, chalcopyrite, and pyrite. Vein thickness ranges from 5 - 17 cm, showing a crustiform banding texture, with a sequence from outer to centre: quartz, carbonate (siderite, sulphide. The quartz displays primary growth textures such as comb, crystalline, saccharoidal, and colloform. Analytical methods applied include AAS and fluid inclusion microthermometry. Chemical composition of the vein indicates an average of Pb = 47.92%, Cu = 1.27%, Zn = 1.02%, and Fe = 9.46%, which shows a significant concentration of Pb. Fluid inclusion microthermometry results indicate a range of formation temperature of 240 - 250C and salinity of the responsible hydrothermal fluid of 2.1 - 2.5 wt.% NaCl eq. The deposit is categorized into low-sulfidation epithermal deposits, which was formed within a range of 410 - 440 m below paleosurface.

  18. Fluid Dynamic Field in Bozhong Depression, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The data from regional geology, boreholes, geophysics and tests are integrated to analyze the fluid dynamic field in the Bozhong depression, Bohai Bay basin. The current geothermal gradient is determined to be about 2.95 ℃/100 m by integrating 266 drill-stem test (DST) measurements and comparing with the global average value. The paleogeothermal gradients are calculated from the homogenization temperatures of saline inclusions, which vary both laterally and vertically. The data from sonic logs, well tests and seismic velocities are used to investigate the pressure variations in the study area. The mudstone compaction is classified as three major types: normal compaction and normal pressure, under-compaction and overpressure, and past-compaction and under-overpressure. The current pressure profile is characterized by normal pressure, slight pressure and intense overpressure from top to bottom. The faults, unconformity surfaces and interconnecting pores constitute a complex network of vertical and horizontal fluid flows within the depression. The fluid potential energy profiles present a “double-deck” structure. The depocenters are the area of fluids supply, whereas the slopes and uplifts are the main areas of fluids charge.

  19. Positive feedback between strain localization and fluid flow at the ductile-brittle transition leading to Pb-Zn-Fe-Cu-Ag ore deposits in Lavrion (Greece)

    Science.gov (United States)

    Scheffer, Christophe; Tarantola, Alexandre; Vanderhaeghe, Olivier

    2016-04-01

    At the crustal scale, the ductile-brittle transition (DBT) might correspond to a physical barrier that separates a deep reservoir of metamorphic and magmatic fluids from a shallow reservoir of surficial fluids. Rock rheology, and thus the location of the DBT, is mainly governed by lithology, temperature and the presence/absence of fluids. Accordingly, the position of the DBT potentially evolves during orogenic evolution owing to thermal evolution and fluid circulation. In turn rocks are transferred across it during burial and exhumation. These processes induce connections between fluid reservoirs which might play a role on ore deposition. In this contribution, we discuss the impact of lithological heterogeneities on deformation, fluid flow and ore deposition based on the example of the Lavrion low-angle top-to-the-SSW detachment accommodating gravitational collapse of the Hellenides orogenic belt in Greece. The Lavrion peninsula, localized along the western boundary of the Attic-Cycladic Metamorphic Core Complex, is characterized by Pb-Zn-Fe-Cu-Ag ore mineralization mainly concentrated along a lithological contact (marble/schists) below and within a detachment shear zone. The mylonitic marble below the detachment shear zone is composed of white layers of pure marble alternating with blue layers containing impurities (SiO2, Al2O3, organic matter…). Development of the mylonitic fabric in competent impure blue marble is associated with its preferred dolomitization related to focused fluid infiltration. This mylonitic marble is cross-cut by several cataclastic horizons preferentially developed within the more competent impure blue marble and newly-crystallized dolomitic horizon. These cataclasites are invaded by fluorite and calcite gangue minerals showing locally Mn, Pb, Zn, Fe oxides and/or hydroxides, sphalerite, Ag-galena, Ag-sulfur and native Ag. Oxygen and carbon stable isotopes performed on marble sections point out decarbonation with magmatic contribution and

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

    Science.gov (United States)

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

    2005-12-01

    Fluid inclusions have been studied in minerals infilling fissures (quartz, calcite, fluorite, anhydrite) hosted by Carboniferous and Permian strata from wells in the central and eastern part of the North German Basin in order to decipher the fluid and gas migration related to basin tectonics. The microthermometric data and the results of laser Raman spectroscopy reveal compelling evidence for multiple events of fluid migration. The fluid systems evolved from a H2O-NaCl±KCl type during early stage of basin subsidence to a H2O-NaCl-CaCl2 type during further burial. Locally, fluid inclusions are enriched in K, Cs, Li, B, Rb and other cations indicating intensive fluid-rock interaction of the saline brines with Lower Permian volcanic rocks or sediments. Fluid migration through Carboniferous sediments was often accompanied by the migration of gases. Aqueous fluid inclusions in quartz from fissures in Carboniferous sedimentary rocks are commonly associated with co-genetically trapped CH4-CO2 inclusions. P-T conditions estimated, via isochore construction, yield pressure conditions between 620 and 1,650 bar and temperatures between 170 and 300°C during fluid entrapment. The migration of CH4-rich gases within the Carboniferous rocks can be related to the main stage of basin subsidence and stages of basin uplift. A different situation is recorded in fluid inclusions in fissure minerals hosted by Permian sandstones and carbonates: aqueous fluid inclusions in calcite, quartz, fluorite and anhydrite are always H2O-NaCl-CaCl2-rich and show homogenization temperatures between 120 and 180°C. Co-genetically trapped gas inclusions are generally less frequent. When present, they show variable N2-CH4 compositions but contain no CO2. P-T reconstructions indicate low-pressure conditions during fluid entrapment, always below 500 bar. The entrapment of N2-CH4 inclusions seems to be related to phases of tectonic uplift during the Upper Cretaceous. A potential source for nitrogen in the

  1. Chemical and stable isotopic geochemical characteristics of ore-forming fluid of the Shizishan copper and gold ore-field, Tongling, China%铜陵狮子山铜金矿田成矿流体成分及稳定同位素地球化学

    Institute of Scientific and Technical Information of China (English)

    陆三明; 徐晓春; 谢巧勤; 楼金伟; 储国正; 熊亚平

    2007-01-01

    Shizishan ore-field is a nonferrous and noble metal ore-field which is most rich in copper and gold. There are many types of fluid inclusions in minerals of the deposits. The homogeneous temperatures and the salinities of the fluid inclusions in main mineralization stages have wide ranges, while the different types of the fluid inclusions existed together and their homogeneous temperatures are almost identical in the same mineralization stage, which indicates that the ore-forming process has great relation with the fluid boiling. The gas and liquid chemical compositions and the carbon, hydrogen and oxygen isotopic compositions of the fluid inclusions show that the ore-forming fluids of copper-gold deposits have the same characteristics and evolution tendency, which reflects that the ore-forming material mainly came from the magmatism. The stratigraphic component and the meteoric water may mix in oreforming fluids in the later mineralization stages. Furthermore, with the fall of the ore-forming temperature the ratios of water and rock decreased. The characteristics of chemical composition and carbon isotopic composition of fluid inclusions indicate that CH4 may play an important role for separating copper and gold in the ore-forming process.

  2. Geochemistry of Brines from Salt Ore Deposits in Western Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    马万栋; 马海州; 谭红兵; 董亚萍; 张西营; 孙国芳

    2004-01-01

    In the geological evolution of the Tarim Basin, many transgressions and relictions happened. So there have been plentiful sources of salt. Moreover, because of uttermost drought, a lot of salt has been deposited. It is possible to find potash salt in this area. In our fieldwork, we have found salt and brine in western Tarim Basin. Based on a geological survey and the characteristics of sedimentary facies and paleogeography, this paper deals with the geochemical parameters and discusses the possibility of formation of potash salt in terms of the chemical analyses of samples collected from western Tarim Basin. Results of brine analysis lead to some conclusions: most of these salt brines have eluviated from very thick halite beds, mainly chloride-type salt and this kind of halite does not reach the stage of potash deposition in all aspects; WKSL (Wukeshalu) occupies a noticeable place, and we should attach importance to this district because there have been some indicators of the occurrence of potash deposits as viewed from the contents of Br and K. Finally, low Br contents are recognized in the Tarim Basin as a result of salt aggradation, and this point of view has been proved by the results of this experiment and the data available. It cannot depend upon the index of Br to judge the evolution stage of halite. We must look for other facies of potash except marine facies.

  3. First Principles Simulations fo the Supercritical Behavior of Ore Forming Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Weare, John H

    2013-04-19

    Abstract of Selected Research Progress: I. First-principles simulation of solvation structure and deprotonation reactions of ore forming metal ions in very nonideal solutions: Advances in algorithms and computational performance achieved in this grant period have allowed the atomic level dynamical simulation of complex nanoscale materials using interparticle forces calculated directly from an accurate density functional solution to the electronic Schrödinger equation (ab-initio molecular dynamics, AIMD). Focus of this program was on the prediction and analysis of the properties of environmentally important ions in aqueous solutions. AIMD methods have provided chemical interpretations of these very complex systems with an unprecedented level of accuracy and detail. The structure of the solvation region neighboring a highly charged metal ion (e.g., 3+) in an aqueous solution is very different from that of bulk water. The many-body behaviors (polarization, charge transfer, etc.) of the ion-water and water-water interactions in this region are difficult to capture with conventional empirical potentials. However, a large numbers of waters (up to 128 waters) are required to fully describe chemical events in the extended hydrations shells and long simulation times are needed to reliably sample the system. Taken together this makes simulation at the 1st principles level a very large computational problem. Our AIMD simulation results using these methods agree with the measured octahedral structure of the 1st solvation shell of Al3+ at the 1st shell boundary and a calculated radius of 1.937Å (exp. 1.9Å). Our calculated average 2nd shell radius agrees remarkably well with the measured radius, 4.093 Å calculated vs. the measured

  4. Geologic and geochemical features of the volatile-rich ore fluid and its tracing and dating in the Xuebaoding Beryl-Scheelite Vein Deposit,China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Laser Raman spectrochemical analysis on single inclusion reveals that multi-phase fluid inclusions exist in the Xuebaoding Beryl-Scheelite Vein Deposit.Besides the solid daughter mineral,there are vapor CO2,liquid CO2,water-deficient CO2 and salt water solution from its center to the border.A close study on the fluid inclusion components and carbon,oxygen,helium and argon isotope tracing and dating suggests that the volatile-rich ore fluid might derive from postmagmatic fluid and rare element enrichment is the result of the mixture of the plutonic alkali granite with crustal material.

  5. Geologic and geochemical features of the volatile-rich ore fluid and its tracing and dating in the Xuebaoding Beryl-Scheelite Vein Deposit, China

    Institute of Scientific and Technical Information of China (English)

    曹志敏; 任建国; 郑建斌; 徐仕进; 李佑国; 王汝成; T.SHOJ; H.KANEDA; S.KABAYASHI

    2002-01-01

    Laser Raman spectrochemical analysis on single inclusion reveals that multi-phase fluid inclusions exist in the Xuebaoding Beryl- Scheelite Vein Deposit. Besides the solid daughter mineral, there are vapor CO2, liquid CO2, water-deficient CO2 and salt water solution from its center to the border. A close study on the fluid inclusion components and carbon, oxygen, helium and argon isotope tracing and dating suggests that the volatile-rich ore fluid might derive from postmagmatic fluid and rare element enrichment is the result of the mixture of the plutonic alkali granite with crustal material.

  6. Laser ablation-ICP-AES for the determination of metals in fluid inclusions: An application to the study of magmatic ore fluids

    Science.gov (United States)

    Wilkinson, J. J.; Rankin, A. H.; Mulshaw, S. C.; Nolan, J.; Ramsey, M. H.

    1994-02-01

    The laser ablation-ICP-AES (L-ICP-AES) technique is an effective method for the multielement analysis of individual fluid inclusions. Recent tests on synthetic fluid inclusions and improvements in data processing suggest that the method is valid for the analysis of a range of alkali-, alkali-earth, and transition metals in single, large inclusions (> 30 μm) of moderate to high salinity (>20 wt% NaCl equiv.). The system, involving a small, perspex ablation chamber, a 1 J ruby laser focussed through an optical microscope, and a conventional ICP-AES instrument is discussed and applied to natural fluid inclusions in quartz from two contrasting types of magmatic-hydrothermal mineralization. Samples were selected from the San Pedro Cu-Au porphyry system, New Mexico, USA, and the Sn-W-Cu-mineralized Dartmoor granite of southwest England. Variable salinity, high temperature fluid inclusions in hydrothermal quartz from both environments display similarly high concentrations and ratios of Na, K, Ca, and Fe. The ore metals Cu, Zn, and Mn (but not Sn, Mo, W) were detected in inclusions from both environments. The estimated combined concentrations of up to 3 wt% show that these three elements are major components of these fluids. A method has been devised to estimate the confidence intervals of the measured concentration ratios. The confidence intervals obtained show that the analytical uncertainty for an inclusion is much less than the natural geochemical variation between inclusions so that geologically useful information can be obtained. A trend of increasing salinity with decreasing Na and K and increasing Ca and Fe contents is observed in inclusions from San Pedro, consistent with the continuous evolution of a magmatic aqueous phase exsolved from a low pressure melt during crystallization. In contrast, the combined compositional and microthermometric data for samples from Lee Moor, Dartmoor, suggest that a magmatic aqueous phase evolved from Fe-K-rich to Na

  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

    Science.gov (United States)

    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. Triassic fluid mobilization and epigenetic lead-zinc sulphide mineralization in the Transdanubian Shear Zone (Pannonian Basin, Hungary

    Directory of Open Access Journals (Sweden)

    Benkó Zsolt

    2014-06-01

    Full Text Available A combined fluid inclusion, fluid inclusion plane, lead isotope and K/Ar radiometric age dating work has been carried out on two lead-zinc mineralizations situated along the Periadriatic-Balaton Lineament in the central part of the Pannonian Basin, in order to reveal their age and genetics as well as temporal-spatial relationships to other lead-zincfluorite mineralization in the Alp-Carpathian region. According to fluid inclusion studies, the formation of the quartzfluorite- galena-sphalerite veins in the Velence Mts is the result of mixing of low (0-12 NaCl equiv. wt. % and high salinity (10-26 CaCl2 equiv. wt. % brines. Well-crystallized (R3-type illite associated with the mineralized hydrothermal veins indicates that the maximum temperature of the hydrothermal fluids could have been around 250 °C. K/Ar radiometric ages of illite, separated from the hydrothermal veins provided ages of 209-232 Ma, supporting the Mid- to Late-Triassic age of the hydrothermal fluid flow. Fluid inclusion plane studies have revealed that hydrothermal circulation was regional in the granite, but more intensive around the mineralized zones. Lead isotope signatures of hydrothermal veins in the Velence Mts (206Pb/204Pb = 18.278-18.363, 207Pb/204Pb = 15.622-15.690 and 208Pb/204Pb = 38.439-38.587 and in Szabadbattyán (206Pb/204Pb = 18.286-18.348, 207Pb/204Pb = 15.667-15.736 and 208Pb/204Pb = 38.552-38.781 form a tight cluster indicating similar, upper crustal source of the lead in the two mineralizations. The nature of mineralizing fluids, age of the fluid flow, as well as lead isotopic signatures of ore minerals point towards a genetic link between epigenetic carbonate-hosted stratiform-stratabound Alpine-type lead-zinc-fluorite deposits in the Southern and Eastern Alps and the studied deposits in the Velence Mts and at Szabadbattyán. In spite of the differences in host rocks and the depth of the ore precipitation, it is suggested that the studied deposits along the

  9. Lithofacies characteristics of ore-hosting horizon and its relationship to uranium mineralization in Qianjiadian uranium deposit, Songliao basin

    International Nuclear Information System (INIS)

    The host rocks of Qianjiadian uranium deposit in Songliao basin is composed of thick bed sand- bodies, which are formed by braided stream sediment in Yaojia formation. The thick bed sandbody has favorable upper and lower waterproof layer, and has lenticular mudstone interlayer in some parts. On plane, the flood plain face locates around the braided stream face, which is mainly composed of sediments of argillaceous rock. In the middle of braided stream, distributes interchannel sediments, which has thicker mudstone interlayer and thinner sand bodies, and the sand body of these place is more heterogeous than others. Based on the analysis on oxidation zone and uranium mineralization, it is found that the distribution and configuration of oxidation zone and ore bodies are obviously controlled by the lithofaties characteristics and sandbody heterogeneity of Yaojia formation. The reason is that the movement of uranium-bearing oxidizing ground water can be obstructed by interchannel sediments and pelitic interbeds of host sandstones. As a result, the redox interface will be developed and uranium can be concentrated in neighbouring sandstones. The sandbodies with greater homogeneity are favorable for the formation of oxidation zone, and sandbodies with greater heterogeneity are favorable for the uranium mineralization. (authors)

  10. A simulating experiment on the geochemical variation trend at the initial period of meteoric waters converting to underground waters and ore fluids

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiaoqing; HUANG Yan; ZHANG Qian; HE Yuliang; ZHU Chaohui

    2005-01-01

    Experimental studies were undertaken on leaching of sedimentary rocks (dolomite and sandstone) and Hg, Sb ores by distilled water under the condition of a completely open system (room temperature and room pressure). The aim is to find whether the halogen elements or metal elements first enter the solution at the early stage of meteoric waters converting to groundwaters and ore fluids, and, at the same time, to understand how and when they enter distilled water solutions from the rocks. The experimental results have shown that F and Cl began to enter the fluids in the initial period of thirty days. With increasing leaching duration, the amounts of the elements that entered the fluids increased steadily. During the period from 120 days to 150 days the amounts increased more drastically, followed a slow increase. It is found that the capability of Cl entering the solutions is much greater than that of F. Hg and Sb were found not to have entered the solutions till 120 days later. During this period of time the pH value of the solutions began to drop. As for Hg and Sb ores, Hg and Sb began to enter the solutions on the 60th or 90th day, greatly ahead of schedule, but the two metallic elements in the rock samples began to enter the solutions 150 days later. Relatively speaking, Hg is more easily leached out than Sb from the rocks. In some rock samples, Sb could be detected in the solutions at the end of the experiment. However, Cu, Pb and Zn had not been detected in the leaching solutions from the beginning to the end of the experiment. In the whole leaching process the pH value of the solutions tend to decrease slowly from 7.1 at the beginning to 6.5 at the end. That is to say, in the interaction between pure water and rock the halogen elements in the rocks were preferentially leached out and then entered the fluids. With increasing water/rock reaction duration and amount of halogen-group elements in the solution and with decreasing pH value of the solution, some active

  11. Characteristics of polymetallic ore-forming fluid and metallogenesis of the Xiangshan ore-field in Jiangxi%江西相山矿田多金属成矿流体特征与成矿作用

    Institute of Scientific and Technical Information of China (English)

    聂江涛; 李子颖; 王健; 郭建

    2015-01-01

    Fluid inclusions of polymetallic mineralization in the Xiangshan uranium orefield were studied for the first time in this pa⁃per. A large number of polymetallic mineralizations were discovered recently with the deepening of geological exploration in the Xiangshan uranium orefield and the implementation of uranium scientific deep drilling. Based on studying petrography, microther⁃mometry, pressure of ore-forming processes, composition and metallogenic depth of fluid inclusions as well as sulfur, carbon, oxygen isotopic composition, the authors hold that the lead and zinc ore-forming temperatures are mainly concentrated on 230~300℃, the metallogenic pressures are concentrated on 12~51MPa, and the salinities are concentrated on 4%~12%NaCleqv. The fluid inclusions are enriched in CO2 and to a lesser extent in CH4 and N2. The mineral assemblage is mainly sphalerite+gelenite+pyrite. The cop⁃per ore-forming temperatures are mainly concentrated on 320~380℃,metallogenic pressures on 33~95MPa , and salinities on 4%~12%NaCleqv. The fluid inclusions are enriched in CO2 and to a lesser extent in CH4 and N2. The mineral assemblage is mainly chal⁃copyrite+pyrrhotite+arsenikstein. All these data indicate that ore-forming fluids were characterized by medium-high temperature, high pressure, medium-high salinity, low oxygen fugacity and high content of CO 2. The lead, zinc, copper and uranium ore-form⁃ing fluids were characterized by deep source, but there were obvious different in stage, space, alteration and fluid inclusion characteris⁃tics of lead, zinc, copper and uranium mineralization, so they were formed in different ore-forming stages and occurred in different separate hydrothermal mineralization processes in early-middle Cretaceous in South China.%随着相山铀矿矿田勘探深度的增加和铀矿科学深钻的实施,在矿田内揭露了大量多金属矿化,流体包裹体和地球化学研究表明,铅锌矿成矿期温度集中在230~300

  12. Ore-forming mechanism for the Xiaoxinancha Au-rich Cu deposit in Yanbian,Jilin Province,China:Evidence from noble gas isotope geochemistry of fluid inclusions in minerals

    Institute of Scientific and Technical Information of China (English)

    KEISUKE; Nagao; HIROCHIKA; Sumino

    2008-01-01

    The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and40Ar/36Ar are in the ranges of 4.45―0.08 Ra, 10.2―8.8 and 306―430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123―102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition-crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as

  13. Helium, Argon, and Xenon Isotopic Compositions of Ore-forming Fluids in Jinding-Baiyangping Polymetallic Deposits,Yunnan, Southwest China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Jinding superlarge lead and zinc deposit has attracted the attention of geologists of the world and its metallogenesis has long been in dispute. This paper takes the Jinding deposit and the Baiyangping Cu-Ag-Co deposit which was recently found at about 30 km north of Jinding as one ore belt, and, based on researches on the helium, argon, and xenon isotopic compositions of primary inclusions in ore-forming solutions of the main stage, the authors have found that the 3He/4He ratio of the ore-forming fluid is 2.7′ 10- 6 (varying from 0.19 to 1.97 Ra), the 4He/40Ar ratio (0.24- 3.12) is close to the mantle characteristic ratio, and the xenon isotopic composition and evolution show characters of the mantle xenon. The above results reveal the characteristics of mantle source and crust-mantle fluid mixing (mantle helium reaching 32%) and the metallogenic contributions of the deep processes in the Jinding-Baiyangping ore belt.

  14. Evaluation of the Cerro Solo nuclear ore, province of Chubut. Geological characteristics of the deposit and of the basin. Pt. 2

    International Nuclear Information System (INIS)

    The Cerro Solo uranium ore deposit, is located 420 km west from Trelew city, Chubut province, in the extra-andean. The geologic environment belongs to the northwest edge portion of the intracratonic San Jorge Gulf Basin. The uraniferous district is named Pichinanes Ridge district. The mineralization lies 25 to 130 m depth, and is hosted by Los Adobes formation aged Aptian-Albian, made up by conglomerates, sandstones, coarse-sandstones and less abundant siltstones and claystones. The Cerro Solo ore deposit that belongs to the sandstone type-uranium occurrences are lenticular or tabular shaped, associated with organic material and pyrite, generally roughly parallel to the bedding (Trend-Type). The uranium minerals are uraninite and coffinite associated with organic material and pyrite, and frequently hematite, goethite, calcite, siderite and barite are observed. (Author)

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

    Science.gov (United States)

    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

  16. Regional Fluid Flow and Basin Modeling in Northern Alaska

    Science.gov (United States)

    Kelley, Karen D.

    2007-01-01

    INTRODUCTION The foothills of the Brooks Range contain an enormous accumulation of zinc (Zn) in the form of zinc sulfide and barium (Ba) in the form of barite in Carboniferous shale, chert, and mudstone. Most of the resources and reserves of Zn occur in the Red Dog deposit and others in the Red Dog district; these resources and reserves surpass those of most deposits worldwide in terms of size and grade. In addition to zinc and lead sulfides (which contain silver, Ag) and barite, correlative strata host phosphate deposits. Furthermore, prolific hydrocarbon source rocks of Carboniferous and Triassic to Early Jurassic age generated considerable amounts of petroleum that may have contributed to the world-class petroleum resources of the North Slope. Deposits of Zn-Pb-Ag or barite as large as those in the Brooks Range are very rare on a global basis and, accordingly, multiple coincident favorable factors must be invoked to explain their origins. To improve our understanding of these factors and to contribute to more effective assessments of resources in sedimentary basins of northern Alaska and throughout the world, the Mineral Resources Program and the Energy Resources Program of the U.S. Geological Survey (USGS) initiated a project that was aimed at understanding the petroleum maturation and mineralization history of parts of the Brooks Range that were previously poorly characterized. The project, titled ?Regional Fluid Flow and Basin Modeling in Northern Alaska,? was undertaken in collaboration with industry, academia, and other government agencies. This Circular contains papers that describe the results of the recently completed project. The studies that are highlighted in these papers have led to a better understanding of the following: *The complex sedimentary facies relationships and depositional settings and the geochemistry of the sedimentary rocks that host the deposits (sections 2 and 3). *The factors responsible for formation of the barite and zinc deposits

  17. Source of ore-forming fluids of the Tianbaoshan Pb-Zn deposit, Southwest China: constrains from C-O, S, and He-Ar isotopes

    Science.gov (United States)

    Wang, Jian; Zhang, Jun; Zhong, Wenbin

    2016-04-01

    The Sichuan-Yunnan-Guizhou (SYG) metallogenic province is one of the most important areas for Pb-Zn resources in China. The metallogenic sources of these Pb-Zn deposits have long been debated. In this study, we provide integrated C-O-S-He-Ar isotopic data of the typical Tianbaoshan Pb-Zn deposit, with an aim to constrain the sources of ore-forming fluids. The Tianbaoshan deposit a large-sized Pb-Zn deposit in SYG metallogenic province, Southwest China. The proven resources include 2.6 Mt metals of Zn+Pb with average grades of 10.09% Zn and 1.50% Pb. The orebodies are hosted within the carbonates of the Ediacaran Dengying Formation. Ore minerals consist mainly of sphalerite, galena, chalcopyrite, and pyrite. Gangue minerals are dominated by calcite and dolomite. The calcite samples from the Tianbaoshan deposit yield homogeneous δ13CV ‑PDBvalues of -1.70‰ to -1.60‰ (average -1.63), with δ18OV ‑SMOW values ranging from 12.9‰ to 15.2‰ (average 14.4). The C-O isotopic data suggest the hydrothermal fluids may be originated from a mixed source involving both mantle and carbonate wall rocks. The δ34S values of the sphalerite, galena and chalcopyrite samples vary from 3.32‰ to 5.71‰ -0.36‰ to 1.31‰ and 4.5‰ to 4.7‰ respectively, indicating a magmatic source for sulfur. The 3He/4He ratios of chalcopyrite samples range from 0.01 to 0.32 Ra which is slightly higher than the crustal ratios (0.05 Ra), but obviously lower than that of mantle fluids (6 to 9 Ra). The 40Ar/36Ar ratios range from 345.0 to 669.1, which are slightly higher than that of air (298.5). The He-Ar isotopic compositions suggest that the ore-forming fluids are dominantly derived from the crust, with litter contamination from mantle-derived fluids. In combination with the C-O, S, and He-Ar isotopic data, we propose the ore-forming fluids of the Tianbaoshan deposit were derived by mixing of crustal and mantle fluids. And the metallogenic process may be genetically related to the

  18. Sulfur isotope geochemistry of ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type ore district, Poland

    Science.gov (United States)

    Leach, D.L.; Vets, J.G.; Gent, C.A.

    1996-01-01

    Studies of the sulfur isotopic composition of ore and gangue minerals from the Silesian-Cracow Zn-Pb district were conducted to gain insights into processes that controlled the location and distribution of the ore deposits. Results of this study show that minerals from the Silesian-Cracow ore district have the largest range of sulfur isotope compositions in sulfides observed from any Mississippi Valley-type ore district in the world. The ??34S values for sulfide minerals range from +38 to -32 per mil for the entire paragenetic sequence but individual stages exhibit smaller ranges. There is a well developed correlation between the sulfur isotope composition and paragenetic stage of ore deposition. The first important ore stage contains mostly positive ??34S values, around 5 per mil. The second stage of ore formation are lower, with a median value of around -5 to -15 per mil, and with some values as low as -32 per mil. Late stage barite contains isotopically heavy sulfur around +32 per mil. The range in sulfur isotope compositions can be explained by contributions of sulfur from a variety of source rocks together with sulfur isotope fractionations produced by the reaction paths for sulfate reduction. Much of the variation in sulfur isotope compositions can be explained by bacterial reduction of sedimentary sulfate and disequilibrium reactions by intermediate-valency sulfur species, especially in the late-stage pyrite and sphalerite. Organic reduction of sulfate and thermal release of sulfur from coals in the Upper Silesian Coal Basin may have been important contributors to sulfur in the ore minerals. The sulfur isotopic data, ore mineral textures, and fluid inclusion data, are consistent with the hypothesis that fluid mixing was the dominant ore forming mechanism. The rather distinct lowering of ?? 34S values in sulfides from stage 2 to stage 3 is believed to reflect some fundamental change in the source of reduced sulfur and/or hydrology of the ore

  19. Thermicity and fluid flow related to the evolution of the South Pyrenean Foreland Basin (SPFB)

    Science.gov (United States)

    Crognier, Nemo; Hoareau, Guilhem; Lacroix, Brice; Aubourg, Charles; Dubois, Michel; Lahfid, Abdeltif; Labaume, Pierre; Suarez-Ruiz, Isabel

    2015-04-01

    The East-West trending South Pyrenean Foreland Basin (SPFB), formed during the upper Cretaceous and the early Miocene due to the collision between Iberian and European plates, is filled by marine to continental deposits affected by a set of successive southvergent thrusts. In the western part of the SPFB (Jaca basin, Spain), from the North to the South the basin is subdivided into four parts: the internal Sierras, the turbiditic basin, the molassic basin and the external Sierras. In order to better constrain the fluid flow dynamic and the thermal regime of the basin during its tectonic evolution, we propose to estimate the temperatures and the O and C isotopic signatures of fluids, as well as the maximum temperatures recorded by pre- to syn-tectonic sediments of the Jaca basin. The C and O isotopic composition has been measured on ~100 veins and host sediment samples. The peak temperatures have also been estimated on 80 bulk rocks and calcite/quartz veins using a combination of several techniques, including Raman Spectroscopy of Carbonaceous Material, vitrinite reflectance, fluid inclusion microthermometry and mass-47 clumped isotopes. We show that in most tectonic fractures, primary fluid inclusions are characterized by moderate salinities (~2.5 wt%) compatible with connate or evolved meteoric waters, with increasing meteoric signature in the south of the basin. As suggested by temperature determinations and stable isotopes, involved fluids were generally in thermal and isotopic equilibrium with the host sediments, suggesting a low fluid-rock ratio (i.e., no significant fluid flow). These results support previous speculations of moderate fluid-flow through thrust faults and the hydrological compartmentalization of the Jaca basin during deformation (Lacroix et al., 2014). In addition we demonstrate that measured peak temperatures rapidly decrease southward, from ~240°C±30°C in Cretaceous to Eocene sediments located in the North of the basin close to the axial

  20. Genesis of the zinc-lead-barite deposits in the northern Iraq: ore mineralogy, geochemistry, fluid inclusions, lead isotopes and sulfur isotopes implications

    International Nuclear Information System (INIS)

    Zinc - leaed - barite deposits hosted by carbonate rocks are studied mineralogically, geochemically and genetically. These deposits (Lefan, lower Banik, Menin and Upper Banik) locate at the Nortgeren Thrust Zone, Northern Iraq. They consistt of sulfides as sphalerite, galena and pyrite, and sulfates as barite. Fluid inclusions observed in barite contain heavy oil associated with aqueous chloride-rich fluids (13% -15.5% wt equv. NaC1). The temperature of formation of barite is suggested to be 50-60 degree. The sulfur isotope composition (δ34S) of early generated galena is 0.36 per mil. This value is close to the hydrothermal magmatic sulfur origin. The δ34S of late generated galena is 6.41 per mil. This value indicates that the hydrothermal magmatic fluids were partially mixeed with oilfield brine connate waters. The δ34S of barite ranges from 16.64 to 24.23 per mil. These values indicate high isotopeic fractionation that caused by descending meteoric waters which diluted the ascending ore-bearing fluids. The lead isotope compostion (204pb, 206pb, 207pb and 208pb) of galeana has revealed that lead was derived from the crust reservoir. Ore metals (Zn, Pb, Fe, and Ba) may have been originated from oilfield brine waters that may have partially been mixed with the hydrothermal fluids of magmatic origin that supplied sulfur. These fluides have migrated upward as chloride and sulfide complexes along fractures and faults possibly after crustal extension and rifting during Alpine orogeny in the Paleocene. Zinc - lead - barite deposits could be classified as epithermal, eigenetic strata-bound of Mississippi Vally type (MVT) deposits, lithologically and structurally controlled within Cretaceous carbonates. (authors).

  1. Lateral fluid flow in a compacting sand-shale sequence: South Caspian basin.

    Science.gov (United States)

    Bredehoeft, J.D.; Djevanshir, R.D.; Belitz, K.R.

    1988-01-01

    The South Caspian basin contains both sands and shales that have pore-fluid pressures substantially in excess of hydrostatic fluid pressure. Pore-pressure data from the South Caspian basin demonstrate that large differences in excess hydraulic head exist between sand and shale. The data indicate that sands are acting as drains for overlying and underlying compacting shales and that fluid flows laterally through the sand on a regional scale from the basin interior northward to points of discharge. The major driving force for the fluid movement is shale compaction. We present a first- order mathematical analysis in an effort to test if the permeability of the sands required to support a regional flow system is reasonable. The results of the analysis suggest regional sand permeabilities ranging from 1 to 30 md; a range that seems reasonable. This result supports the thesis that lateral fluid flow is occurring on a regional scale within the South Caspian basin. If vertical conduits for flow exist within the basin, they are sufficiently impermeable and do not provide a major outlet for the regional flow system. The lateral fluid flow within the sands implies that the stratigraphic sequence is divided into horizontal units that are hydraulically isolated from one another, a conclusion that has important implications for oil and gas migration.-Authors

  2. Fluid Geochemistry and Metallogenesis of the Hatu Gold Deposit in the Junggar Basin, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    WANG Lijuan; WANG Jingbin; WANG Yuwang; ZHU Heping; QU Lili

    2004-01-01

    The Hatu large gold deposit is located on the western margin of the Junggar basin, Xinjiang. Its mineralization is characterized by auriferous quartz veins and Au-bearing altered fracturing zones. Studies on mineralogy, inclusions and decrepitation temperature indicate that the gold deposit was formed by overlapping of two kinds of fluid of different origins, instead of gradual evolution of a single fluid. The auriferous quartz veins are related to magmatism-originated fluid, but the Au-bearing altered fracturing zones to deep-derived fluid. Bonanzas in quartz veins were formed and localized at overlapping positions of two types of fluid under intensive compression.

  3. Percolation of diagenetic fluids in the Archaean basement of the Franceville basin

    Science.gov (United States)

    Mouélé, Idalina Moubiya; Dudoignon, Patrick; Albani, Abderrazak El; Cuney, Michel; Boiron, Marie-Christine; Gauthier-Lafaye, François

    2014-01-01

    The Palaeoproterozoic Franceville basin, Gabon, is mainly known for its high-grade uranium deposits, which are the only ones known to act as natural nuclear fission reactors. Previous work in the Kiéné region investigated the nature of the fluids responsible for these natural nuclear reactors. The present work focuses on the top of the Archaean granitic basement, specifically, to identify and date the successive alteration events that affected this basement just below the unconformity separating it from the Palaeoproterozoic basin. Core from four drill holes crosscutting the basin-basement unconformity have been studied. Dating is based on U-Pb isotopic analyses performed on monazite. The origin of fluids is discussed from the study of fluid inclusion planes (FIP) in quartz from basement granitoids. From the deepest part of the drill holes to the unconformable boundary with the basin, propylitic alteration assemblages are progressively replaced by illite and locally by a phengite + Fe chlorite ± Fe oxide assemblage. Illitic alteration is particularly strong along the sediment-granitoid contact and is associated with quartz dissolution. It was followed by calcite and anhydrite precipitation as fracture fillings. U-Pb isotopic dating outlines three successive events: a 3.0-2.9-Ga primary magmatic event, a 2.6-Ga propylitic alteration and a late 1.9-Ga diagenetic event. Fluid inclusion microthermometry suggests the circulation of three types of fluids: (1) a Na-Ca-rich diagenetic brine, (2) a moderately saline (diagenetic + meteoric) fluid, and (3) a low-salinity fluid of probable meteoric origin. These fluids are similar to those previously identified within the overlying sedimentary rocks of the Franceville basin. Overall, the data collected in this study show that the Proterozoic-Archaean unconformity has operated as a major flow corridor for fluids circulation, around 1.9 Ga. highly saline diagenetic brines; hydrocarbon-rich fluids derived from organic matter

  4. Application of Fluid Inclusions in the Study of Natural Gas Geology in Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    FAN Ai-ping; YANG Ren-chao; FENG Qiao; LIU Yi-qun; HAN Zuo-zhen

    2006-01-01

    The new recently demonstrated reserves of oil and gas in the Ordos basin are found at the top of petroliferous basins in China. Gas pools discovered in recent years in the Permian system have become the main natural gas resource in the basin. Therefore, synthetic research on fluid inclusions should be done in order to ascertain the pool-forming stage, the maturity of organic matters and the properties of Paleo-fluids. The main types of fluid inclusions in the Permian system in the basin include brine inclusions, carbon dioxide inclusions and organic inclusions. Homogenization temperatures (HT) of brine inclusions can be divided into four intervals: 66-83 ℃, 86-108 ℃, 112-138 ℃ and 142-153 ℃. The fluid inclusions in the interval of 112-138 ℃ are much more than that of other intervals, indicating that the second stage of hydrocarbon migration associated with the third temperature interval is the most important stage of gas pool formations. The fluid inclusion has extensive applications in the study of gas geology, not only in ascertaining the formation stage of gas pools, but also in estimating the maturity of organic matter and restoring Paleo-fluids. The result of testing the HT of brine inclusions shows that there are two stages of gas pool formations in the Permian system occurring ±150 Ma and ±100 Ma. The maturity of organic matter is moderate to high, a conclusion based on the color of fluid inclusions (radiated by fluorescence). The high salinity of Paleo-fluids of the NaCl-H2O and CaCl2-H2O systems shows good preservation conditions of the Paleo-fluids. Two stages of reservoir filling, high maturity of organic matter and good preservation conditions are factors favorable for the formation and preservation of large-scale gas pools in the Permian system in the Ordos basin.

  5. REE Geochemistry of Fluorite from the Maoniuping REE Deposit, Sichuan Province, China: Implications for the Source of Ore-forming Fluids

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluorite is one of the main gangue minerals in the Maoniuping REE deposit, Sichuan Province, China. Fluorite with different colors occurs not only within various orebodies, but also in wallrocks of the orefield. Based on REE geochemistry, fluorite in the orefieid can be classified as the LREE-rich, LREE-flat and LREE-depleted types. The three types of fluorite formed at different stages from the same hydrothermal fluid source, with the LREE-rich fluorite forming at the relatively early stage, the LREE-flat fluorite in the middle, and the LREE-depleted fluorite at the latest stage. Various lines of evidence demonstrate that the variation of the REE contents of fluorite shows no relation to the color. The mineralization of the Maoniuping REE deposit is associated spatially and temporally with carbonatite-syenite magmatism and the ore-forming fluids are mainly derived from carbonatite and syenite melts.

  6. Geochemical constraints on the origin of the Kicking Horse and Monarch Mississippi Valley-type lead-zinc ore deposits, southeast British Columbia, Canada

    Science.gov (United States)

    Vandeginste, Veerle; Swennen, Rudy; Gleeson, Sarah A.; Ellam, Rob M.; Osadetz, Kirk; Roure, François

    2007-11-01

    Two Mississippi Valley-type (MVT) ore deposits, Kicking Horse and Monarch, have been studied with the aim of comparing the ores at the two localities and to characterize the origin of the mineralizing fluids and the ore formation process(es). Both deposits are hosted by the Middle Cambrian Cathedral Formation carbonate host rocks, Kicking Horse on the north and Monarch on the south flank of the Kicking Horse valley near Field (SE British Columbia). The ore bodies are situated at the transition of (western) basinal to (eastern) shallow-water strata of the paleo-Pacific passive margin succession in the Cordilleran Foreland Province of the Western Canada Sedimentary Basin. Both deposits are related spatially to normal faults. In both localities, the ore minerals are dominated by pyrite, sphalerite, and galena. Dolomite, minor quartz, and calcite are also present in close association with the ores. The salinity (21-30 wt% NaCl eq.) and homogenization temperatures (63-182°C) measured in fluid inclusions in carbonate, quartz, and sphalerite lie within the typical range of MVT fluid conditions. The good stoichiometry (50-53 mol% CaCO3), low δ18O values (-21 to -14‰ Vienna Peedee belemnite) and relatively high homogenization temperatures (>95°C) of the dolomite suggest the dolomites were formed under burial diagenesis. The ore-forming fluids probably interacted with siliciclastic units, based on elevated Li contents and 87Sr/86Sr ratios, which are highest in the dolomite type after the main ore stage. We propose that the ores formed from the mixing of a downward-infiltrating, sulfur-bearing halite-dissolution fluid with an upward-migrating, metal-rich evaporated seawater fluid, which had already undergone minor mixing with a dilute fluid.

  7. Effects of Overpressured Fluid Flow on Petroleum Accumulation in the Yinggehai Basin

    Institute of Scientific and Technical Information of China (English)

    HAO Fang; DONG Weiliang; ZOU Huayao; JIANG Jianqun

    2004-01-01

    The Yinggehai Basin is a strongly overpressured Cenozoic basin developed in the northern continental sheff of the South China Sea. The flow of overpressured fluids in this basin has given rise to strong effects on petroleum accumulation. (1) The overpressured fluid flow has enhanced the maturation of shallow-buried source rocks, which has caused the source rocks that would have remained immature under the conduction background to be mature for hydrocarbon generation. As a result, the overpressured fluid flow has increased the volume and interval of mature source rocks. (2) The overpressured fluid flow has strong extraction effects on the immature or low-mature source rocks in the shallow parts. This has increased, to some extent, the expulsion efficiency of the source rocks. More importantly, the extraction effects have strongly limited the effectiveness of biomarker parameters from oil and condensate in reflecting the source and maturity of the oil and gas. (3) The flow has caused the sandstones in the shallow parts to get into the late diagenesis stage, and significantly reduced the porosity and penneability of the sandstones. This study confirms that even in sedimentary basins in which no topography-driven groundwater flow systems have ever developed, the cross-formation migration of overpressured fluids and the resultant energy conduction and material exchange can significantly affect the thermal regime, source rock maturation and sandstone diagenesis. As a result, the effects of overpressured fluid flow must be taken into account in analyzing the mechanism of petroleum accumulation.

  8. Fluid dynamics, particulate segregation, chemical processes, and natural ore analog discussions that relate to the potential for criticality in Hanford tanks

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.

    1996-09-27

    This report presents an in-depth review of the potential for nuclear criticality to occur in Hanford defense waste tanks during past, current and future safe storage and maintenance operations. The report also briefly discusses the potential impacts of proposed retrieval activities, although retrieval was not a main focus of scope. After thorough review of fluid dynamic aspects that focus on particle segregation, chemical aspects that focus on solubility and adsorption processes that might concentrate plutonium and/or separate plutonium from the neutron absorbers in the tank waste, and ore-body formation and mining operations, the interdisciplinary team has come to the conclusion that there is negligible risk of nuclear critically under existing storage conditions in Hanford site underground waste storage tanks. Further, for the accident scenarios considered an accidental criticality is incredible.

  9. Genesis of sediment-hosted disseminated-gold deposits by fluid mixing and sulfidization: chemical-reaction-path modeling of ore- depositional processes documented in the Jerritt Canyon district, Nevada

    Science.gov (United States)

    Hofstra, A.H.

    1991-01-01

    Integrated geologic, geochemical, fluid-inclusion, and stable-isotope studies of the gold deposits in the Jerritt Canyon district, Nevada, provide evidence that gold deposition was a consequence of both fluid mixing and sulfidization of host-rock iron. Chemical-reaction-path models of these ore-depositional processes confirm that the combination of fluid mixing, including simultaneous cooling, dilution, and oxidation of the ore fluid, and wall-rock reaction, with sulfidization of reactive iron in the host rock, explains the disseminated nature and small size of the gold and the alteration zonation, mineralogy, and geochemistry observed at Jerritt Canyon and at many other sediment-hosted disseminated gold deposits. -Authors

  10. Conduit System and formation mechanism of heat fluids in diapiric belt of Yinggehai basin,China

    Institute of Scientific and Technical Information of China (English)

    解习农; 李思田; 胡祥云; 董伟良; 张敏强

    1999-01-01

    The conduit system of heat fluids in diapiric belt of Yinggehai basin is dominantly vertical faults and fractures . Detailed research on the formation mechanism and their occurrence features shows that the faults and fractures can be classified into three types: intrastratal dispersive hydrofracture, puncturing fault and upwarping-extensional fault. The development of the fault and fracture system not only resulted in the changes of the temperature and pressure fields in the basin, but also affected the hydrocarbon migration in the overpressured system. These faults and fractures constituted the main pathways for vertical hydrocarbon migration, and opening and closing intermittently led to episodic expulsion of overpressured fluid compartment. Thus there formed the pool-forming model of multi-source mixing and ploy-stage migration and accumulation for hydrocarbons in the Yinggehai basin.

  11. 白云鄂博矿床碳酸岩墙/脉和赋矿白云岩中流体包裹体研究%Fluid inclusion study of carbonatite dykes/veins and ore-hosted dolostone at the Bayan Obo ore deposit

    Institute of Scientific and Technical Information of China (English)

    秦朝建; 裘愉卓; 周国富; 王中刚; 张台荣; 肖国望

    2007-01-01

    Fluid inclusion study has been carried out for the carbonatite dykes/veins and the ore-hosted dolostone of the Bayan Obo superlarge REE-Fe-Nb deposit in order to provide the evidence and constraint for their origin. Based on the detailed geological observation and mineralogical investigation, the heating and cooling stage and laser Raman spectroscopy were mainly used for the laboratory work of this study. Following results have been obtained: (1) The discovery of melt and melt-fluid inclusions from carbonatite dykes/veins in the Dulahara and Jianshan Mountains, combined with the fine-grained (aplitic) texture of rocks, as well as the types and features of fluid inclusions such as CO2 enrichment, higher homogenization temperature, provides a direct evidence for the magmatic origin of these dykes/veins. (2) The carbonatite dykes/veins distributed in two regions, nearby the axis of the Kuangou anticline and in the east to Bayan Obo town, mainly show coarse-grained texture. No melt inclusion was found, and the fluid inclusions possess features of less CO2, lower homogenization temperature and higher salinity. They are tentatively identified as veins formed by some carbonate-rich hydrothermal solution. (3) Bedding carbonate layers/lens within the hanging wall and foot wall of ore-hosted dolostone, previously recognized as of magmatic origin, mainly composed by dolomite. The existence of single phase pure aqueous inclusions with very low homogenization temperature indicates their sedimentary origin. (4) The ore-hosted dolostone possesses apparent bedding and laminated structures. No melt inclusion was found, but, both single phase pure aqueous inclusions and CO2bearing multi-phase fluid inclusions coexisted in dolostones. In the direction towards ore-bodies, the homogenization temperature and CO2 contents of fluid inclusion show an increasing tendency. It indicates the sedimentary origin of dolostone superimposed by late fluid metasomatism.

  12. Pumping test and fluid sampling report - Sawyer No. 1 well, Palo Duro Basin, Texas: unanalyzed data

    International Nuclear Information System (INIS)

    This report describes pumping test and fluid sampling activities performed at the Sawyer No. 1 well, Donley County, Texas. Sawyer No. 1 well is located along the eastern margin of the Palo Duro Basin in an area of active dissolution within the Permian salt section. These data were collected by Stone and Webster Engineering Corporation working in conjunction with the Texas Bureau of Economic Geology as part of a nationwide program to identify potential locations for a nuclear waste repository. These data support studies to determine the hydrologic characteristics of deep water-bearing formations. Formation fluid studies samples were analyzed in order to evaluate fluid migration and age relationships in the Permian Basin. These data were collected from June until October, 1981. Zone isolation for pump testing was accomplished in November, 1981. These data are preliminary. They have been neither analyzed nor evaluated

  13. 湖南省邵阳盆地锰矿层特征及矿床富集规律探讨%Characteristics of manganese ore bed and enrichment regularity of deposits in Shaoyang Basin of Hunan

    Institute of Scientific and Technical Information of China (English)

    马武良

    2016-01-01

    Shaoyang Basin is a hollow zone formed in late Devonian epoch,and Permian Gufeng Formation is the main manganese-bearing horizon of this area.Ore bed 1-2 of Gufeng Formation has low grade of man-ganese.However,the ore beds are characterized by large ore bed thickness,wide distribution and great re-source potential.Therefore,analysis and summarization of the characteristics of manganese-bearing ore beds and the enrichment regularity of deposits has great implications for next round prospecting works of manga-nese in Shaoyang Basin.%邵阳盆地为泥盆世晚期形成的一凹陷带,二叠系孤峰组为该区主要含锰层位。孤峰组含锰1~2层品位较低,但矿层厚度大,分布面积广,资源潜力大,因此分析总结锰矿层特征、矿床富集规律,对指导邵阳盆地开展新一轮锰矿找矿工作具有重要意义。

  14. 相山居隆庵矿床铀成矿流体特征及其来源探讨%Characteristics and origin of ore-forming fluid of Julong'an uranium deposit in Xiangshan uranium orefield

    Institute of Scientific and Technical Information of China (English)

    邱林飞; 欧光习; 张敏; 张建锋

    2012-01-01

    On the basis of field survey, comparative study of petrography, microthermometry, Laser Raman ingredient and gas chromatogram ingredient of fluid inclusions, the authors found out the basic characteristics (temperature, salinity, ingredients etc. )of the ore-forming fluids in the Julong'an uranium deposit. According to the compositions of carbon, hydrogen and oxygen stable isotopes of ore-forming fluids in combination with the characteristics of geological structure of the Julong'an uranium deposit, this paper investigated the origin of the ore-forming fluids. The results indicate that the ore-forming fluids were medium- to high- temperature and medium- to high- salinity fluids which were enriched with abundant ore-forming materials and volatiles such as CO2, H2 and CH4, and contained lots of such materials as alkali metals, P and halogen. The ore-forming fluids were mostly deep-derived (mantle source) fluids.%通过居隆庵矿床流体包裹体岩相学、显微测温学、单个流体包裹体激光拉曼成分及群体包裹体成分的对比研究,查明了成矿流体的基本性质(温度、盐度及成分等);根据成矿流体的碳、氢、氧等稳定同位素特征,并结合矿床的地质-构造特征,探讨了成矿流体的来源.研究表明,居隆庵矿床铀成矿流体为富含成矿物质及挥发分(CO2、H2、CHl4等)的中-高温、中-高盐度流体,其成分以C、H、O、N等为主,并溶有多种碱金属、P及卤素(F、C1)等微量组分的C-H-O流体,成矿流体具有深源(幔源)性的特点.

  15. Mechanism of diapirism and episodic fluid injections in the Yinggehai Basin

    Institute of Scientific and Technical Information of China (English)

    HAO; Fang

    2002-01-01

    [1]Jackson, M. P. A., Vendeville, B. C., Regional extension as a geologic trigger for diapirism, Geological Society of Ameri-ca Bulletin, 1994, 106(1): 57-73.[2]Pérez-Belzuz, F., Alonso, B., Ercilla, G., History of mud diapirism and trigger mechanisms in the Western Alboran Sea, Tectonophysics, 1996, 282(2): 399-422.[3]Hunt, J. M., Petroleum Geology and Geochemistry, 2nd ed., San Francisco: Freeman and Company, 1996, 743.[4]Gong Zaisheng, Li Sitian, Continental Margin Basin Analysis and Hydrocarbon Accumulation of the Northern South Chi-na Sea (in Chinese), Beijing: Science Press, 1997, 510.[5]Price, L. C., Basin richness and source rock disruption: A fundamental relationship? Journal of Petroleum Geology, 1994, 17(1): 5-38.[6]Roberts, S. J., Nunn, J. A., Episodic fluid expulsion from geopressured sediments, Marine and Petroleum Geology, 1995, 12(2): 195-204.[7]Dewers, T., Ortoleva, P., Nonlinear dynamical aspects of deep basin hydrology: Fluid compartment formation and episodic fluid release, American Journal of Science, 1994, 294(5): 713-755.[8]Dai, J. X., Song, Y., Dai, C. S. et al., Geochemistry and accumulation of carbon dioxide gases in China, AAPG Bulletin, 1996, 80(9): 1615-1626.[9]Hao Fang, Li Sitian, Sun Yongchuan et al., Organic maturation and petroleum generation model in the Yinggehai and Qiongdongnan Basins, Science in China, 1996, 39(6): 650-658.[10]Hao Fang, Li Sitian, Dong Weiliang et al., Abnormal organic matter maturation in the Yinggehai Basin, offshore South China Sea: Implications for hydrocarbon expulsion and fluid migration from overpressured systems, Journal of Petroleum Geology, 1998, 21(4): 427-444.[11]Pollastro, R. M., Considerations and applications of the illite/smectite geothermometer in hydrocarbon-bearing rocks of Miocene to Mississippian age, Clays and Clay Minerals, 1993, 41(2): 119-133.[12]Ko, J., Hesse, R., Illite/smectite diagenesis in the Beaufort-Mackenzie Basin, Arctic Canada

  16. Environment of ore deposition in the creede mining district, San Juan Mountains, Colorado: Part V. Epithermal mineralization from fluid mixing in the OH vein

    Science.gov (United States)

    Hayba, D.O.

    1997-01-01

    Detailed fluid inclusion studies on coarse-grained sphalerite from the OH vein, Creede, Colorado, have shown that the abrupt color changes between growth zones correspond to abrupt changes in the nature of the ore fluids. Within each growth zone, however, the composition of the fluids remained constant. The base of a distinctive orange-brown growth zone marks a sharp increase in both temperature and salinity relative to the preceding yellow-white zone. The orange-brown growth zone can be correlated along much of the vein and is believed to represent a time-stratigraphic interval. Along the vein, temperatures and salinities of fluid inclusions within this interval show a systematic decrease from about 285??C and 11.5 wt percent NaCl equiv near the base of the vein to about 250??C and 8 wt percent NaCl equiv, respectively, near the top of the vein. The iron concentration of this sphalerite growth zone shows a similar pattern, decreasing from about 2.8 to 1.2 mole percent FeS. When plotted on an enthalpy-salinity diagram, the fluid inclusion data define a spatial trend indicating the progressive mixing of deeply circulating hydrothermal brines with overlying, dilute ground waters. The hydrothermal brines entered the OH vein from below at a temperature, salinity, and density of approximately 285??C, 11.5 wt percent NaCl equiv, and 860 kg/m3, respectively, whereas the overlying ground waters appear to have been preheated to roughly 150??C and had an assumed salinity of 0 wt percent and a density of 920 kg/m3. The greater density of the heated ground water promoted mixing with the hydrothermal brine within the open fractures, causing sphalerite deposition. Although there were also episodes of boiling during vein mineralization, boiling appears unimportant for this sphalerite. Isotopic evidence and geochemical modeling studies also indicate that mixing was the depositional mechanism for sphalerite. An important aspect of the mixing hydrology of the Creede system involves

  17. Vein mineralizations - record of paleo-fluid systems in the Thuringian basin (Germany)

    Science.gov (United States)

    Lepetit, Petra; Viereck, Lothar; Abratis, Michael; Fritsch, Stefanie

    2014-05-01

    Vein-related mineralizations within the Mesozoic sediments of the Thuringian basin (Germany) are investigated in analytical detail (petrography, XRD, XRF, EPMA, LA-ICP-MS, and isotope studies: O, C, S, Sr) in order to characterize paleo-fluid systems that intruded the basin and circulated within it millions of years ago. Samples from 55 outcrops, 34 quarries and 21 drill cores comprise mainly carbonates (calcite, dolomite, siderite, ankerite), additional sulfates (gypsum, celestine, barite,), and rarely sulfides. The mineralizations are almost exclusively restricted to WNW-ESE trending fault systems. First δ13C and δ18O isotope analyses of calcite mineralizations reveal differences between veins within Triassic sediments (Lower Muschelkalk: δ13C: 1.8 to 2.9 o, mean 2.3 o, δ18O: -7.3 to -10.4 o, mean -8.2 o) and Jurassic sediments (δ13C: -0.7 to -2.1 o, mean -1.4 o, δ18O: -9.3 to -10.6 o, mean -9.9 o), indicating intra-formational and extra-formational paleo-fluid transport. Also first δ34S and δ18O isotope analyses of gypsum mineralizations display differences between veins within Triassic and Permian sediments, respectively. These initial data are comparable with isotope analyses of vein-related host rocks and hydrochemical signatures of recent well waters in the Thuringian basin indicating intra-formational in addition to extra-formational paleo-fluid transport. Further isotope studies are in progress including high resolution in situ-Sr- isotope analysis. The present study is part of INFLUINS, a BMBF-funded project bundle, which is dedicated to the comprehensive description and understanding of the fluid systems within the Thuringian basin in time and space.

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

    Science.gov (United States)

    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.

  19. Numerical modeling of fracking fluid migration through fault zones and fractures in the North German Basin

    Science.gov (United States)

    Pfunt, Helena; Houben, Georg; Himmelsbach, Thomas

    2016-09-01

    Gas production from shale formations by hydraulic fracturing has raised concerns about the effects on the quality of fresh groundwater. The migration of injected fracking fluids towards the surface was investigated in the North German Basin, based on the known standard lithology. This included cases with natural preferential pathways such as permeable fault zones and fracture networks. Conservative assumptions were applied in the simulation of flow and mass transport triggered by a high pressure boundary of up to 50 MPa excess pressure. The results show no significant fluid migration for a case with undisturbed cap rocks and a maximum of 41 m vertical transport within a permeable fault zone during the pressurization. Open fractures, if present, strongly control the flow field and migration; here vertical transport of fracking fluids reaches up to 200 m during hydraulic fracturing simulation. Long-term transport of the injected water was simulated for 300 years. The fracking fluid rises vertically within the fault zone up to 485 m due to buoyancy. Progressively, it is transported horizontally into sandstone layers, following the natural groundwater flow direction. In the long-term, the injected fluids are diluted to minor concentrations. Despite the presence of permeable pathways, the injected fracking fluids in the reported model did not reach near-surface aquifers, either during the hydraulic fracturing or in the long term. Therefore, the probability of impacts on shallow groundwater by the rise of fracking fluids from a deep shale-gas formation through the geological underground to the surface is small.

  20. Numerical modeling of fracking fluid migration through fault zones and fractures in the North German Basin

    Science.gov (United States)

    Pfunt, Helena; Houben, Georg; Himmelsbach, Thomas

    2016-04-01

    Gas production from shale formations by hydraulic fracturing has raised concerns about the effects on the quality of fresh groundwater. The migration of injected fracking fluids towards the surface was investigated in the North German Basin, based on the known standard lithology. This included cases with natural preferential pathways such as permeable fault zones and fracture networks. Conservative assumptions were applied in the simulation of flow and mass transport triggered by a high pressure boundary of up to 50 MPa excess pressure. The results show no significant fluid migration for a case with undisturbed cap rocks and a maximum of 41 m vertical transport within a permeable fault zone during the pressurization. Open fractures, if present, strongly control the flow field and migration; here vertical transport of fracking fluids reaches up to 200 m during hydraulic fracturing simulation. Long-term transport of the injected water was simulated for 300 years. The fracking fluid rises vertically within the fault zone up to 485 m due to buoyancy. Progressively, it is transported horizontally into sandstone layers, following the natural groundwater flow direction. In the long-term, the injected fluids are diluted to minor concentrations. Despite the presence of permeable pathways, the injected fracking fluids in the reported model did not reach near-surface aquifers, either during the hydraulic fracturing or in the long term. Therefore, the probability of impacts on shallow groundwater by the rise of fracking fluids from a deep shale-gas formation through the geological underground to the surface is small.

  1. Well successfully drilled with high performance water-based fluid: Santos Basins, offshore Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fornasier, Frank C.; Luzardo, Juan P. [Halliburton Company, Houston, TX (United States); Bishnoi, M.L. [Oil and Natural Gas Corporation Ltda. (ONGC), Dehradun (India)

    2012-07-01

    Santos Basin is a 352,260 square kilometers (136,010 sq mi) offshore pre-salt basin. It is located in the South Atlantic Ocean, some 300 kilometers (190 mi) South East of Sao Paulo, Brazil. One of the largest Brazilian sedimentary basins, it is the site of several recent significant oil fields, including Tupi and Jupiter. The criteria for drilling fluid selection is based upon the following factors: maximum cost efficiency, environmental friendliness, optimum borehole stability, and ease of use. The recommended drilling fluid formulation takes into consideration the experience gained during the drilling of wells in the Santos Basin area. The operator wanted to use a high-performance water-based fluid (HPWBF) that could provide shale inhibition, wellbore stability, lubricity and improved rate of penetration (ROP) as an alternative to synthetic-based drilling fluids to present value in terms of economics and environmental friendliness. The HPWBF consists of three synergistic products: a hydration suppressant, a dispersion suppressant, and an accretion suppressant. The system is formulated based on customized solutions for managing the clay reactivity. High logistics costs require drilling fluids that can be prepared with sea water and discharged to the sea without environmental impact. The HPWBF is a clay-free system designed for maximum shale inhibition in highly reactive formations. The system can provide wellbore stability, high rates of penetration, and acceptable rheological properties over a wide range of temperatures, with the added benefit of allowing cuttings discharge based upon water base environmental restrictions. Since no oil is used in the formulation, the HPWBF eliminates the need for cuttings processing and monitoring equipment, and exceeds the environmental requirements by achieving an LC50 value of 345,478.22 ppm in comparison with the minimum requirement (LC50 > 30,000 ppm in 96 hr), permitting use and discharge to the sea. The HPWBF selected

  2. Pumping test and fluid sampling report - Mansfield No. 1 (PD-4) well, Palo Duro Basin, Texas: unanalyzed data

    International Nuclear Information System (INIS)

    This report contains pumping test and fluid sampling data collected at Mansfield No. 1 well, located in Oldham County, in the Permian Basin of Texas. These data were collected by Stone and Webster Engineering Corporation to support studies of fluid migration and age relationships in the Permian Basin. The testing and sampling took place between October 1981 and October 1982. These data are preliminary. They have been neither analyzed nor evaluated. 4 references, 8 figures, 2 tables

  3. Mechanism of diapirism and episodic fluid injections in the Yinggehai Basin

    Institute of Scientific and Technical Information of China (English)

    郝芳; 李思田; 龚再升; 杨甲明

    2002-01-01

    The diapirism in the Yinggehai Basin is a combined result of strong overpressure caused by rapid sedimentation of fine-grain sediments and the tensile stress field resulting from right-lateral slip of the boundary-fault. The diapirism showed multiple-stage, episodic nature, and caused intermittent counter-direction onlaps and changes in the thickness of strata. The shallow gas reservoirs in the diapir structural zone displayed obvious inter-reservoir compositional heterogeneities, and their filling history could be divided into 4 stages, with gases injected during different stages having different hydrocarbon gas, CO2 and N2 contents and different stable isotope compositions. The multiple-episode, intermittent activities of the diapirs, multiple-stage, non-continuous injections of fluids, and the transient thermal effect of fluid flow as well as the strong migration fractionation reflected episodic fluid injection and natural gas accumulation.

  4. Light Hydrocarbons in Fluid Inclusions and Their Constraints on Ore Genesis:A Case Study of the Songxi Ag(Sb) Deposit,Eastern Guangdong,China

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaoming; David I.NORMAN; SUN Kai; WANG Min; CHEN Binghui; CHEN Jingde; YU Shoujun

    2003-01-01

    The Songxi deposit is a newly discovered large Ag (Sb) deposit. By using a suite of high-vacuum quadrupole gas mass spectrometer systems, the authors have recognized many kinds of light hydrocarbons in fluid inclusions of minerals. These hydrocarbons are mainly composed of C1-C4 saturated alkanes, while the contents of C2-C4 unsaturated alkenes and aromatic hydrocarbons are quite low, suggesting that the metallogenic processes have not been affected by magmatic activities. Chemical equilibrium studies show that these hydrocarbons may be a mixture of organic gases generated by microorganism activity and those by thermal cracking of type-II kerogens (kukersite) in sedimentary host rocks, and the former may constitute more than two-thirds, implying that microorganism might have played an important role in the metallogenesis. The equilibrium temperature of the latter is about 300(C, which is much higher than the geothermal temperature at the estimated depth of metallogenesis. Thus, the light hydrocarbons generated by thermal cracking of kerogens probably originated in the deep part of the sedimentary basins and then migrated through a long distance to shallower horizons of the basin. Based on the composition of light hydrocarbons in fluid inclusions, the authors infer that the Songxi deposit was formed in a continental rift. The analytical data presented in this paper support from one aspect the genetic model that the Songxi deposit may be a sedimentary hot brine transformed deposit instead of a submarine basic volcanic exhalation and low-medium temperature volcanic hydrothermal fluid filling deposit proposed by most previous researchers.

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

    Science.gov (United States)

    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.

  6. Heat transfer and fluid flow modelling in supra-detachment basins: a case study of the Devonian basins of western Norway

    Science.gov (United States)

    Souche, A.; Dabrowski, M.; Andersen, T. B.; Medvedev, S.

    2012-04-01

    The Devonian basins of western Norway are supra-detachment basins located above a large crustal-scale detachment system, so-called the Nordfjord Sogn Detachment Zone. These basins are characterised by a thick succession (>10km) of siliciclastic sediments ranging in size from coarse conglomerates to fine grain sandstones and organized into narrow half-graben systems. Their architecture and geometry is closely controlled by the development of the coeval (i.e. Early to Middle Devonian) detachment acting as a normal fault/shear zone beneath the basins. The exhumation of rocks within the footwall of the detachment was subsequently followed by an increase of the geothermal gradient at the base of the sedimentary successions. Shear heating resulting from the intense rock deformation within the shear zone also played a role in increasing the temperature at the base of the basins. These two significant processes might have in turn contributed to the fluid mobility in the basins. In this study, we explore the feasibility of porous convection to occur spontaneously in sedimentary basins due to a regional increase of the geothermal gradient. Such process can be approximated by Darcy flow through porous media where the fluid density in the system might introduce a buoyancy-driven instability between lighter hot fluids at the base and denser cold fluids at the top of the basin. In geological systems porous flow might be inhibited by the closing of pores with depth, which leads to a reduced permeability and a limited amount of heat carrying fluids. Also, geological heterogeneities inherited from the layered structure of the sedimentary strata introduce large variations in the rock transport properties. We address these problems numerically by modelling heat and mass transport in porous media assuming quasi-incompressible Darcy flow. The fluid (water) density, viscosity, and specific heat are computed from the pore fluid pressure and the temperature. We investigate the onset of

  7. Natural gas leakage of Mizhi gas reservoir in Ordos Basin, recorded by natural gas fluid inclusion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abundant natural gas inclusions were found in calcite veins filled in fractures of Central Fault Belt across the centre of Ordos Basin. Time of the calcite veins and characteristics of natural gas fluid inclusion were investigated by means of dating of thermolum luminescence (TL) and analyzing stable isotope of fluid inclusion. Results show that natural gas inclusion formed at 130―140℃ with salinity of 5.5 wt%―6.0 wt% NaCl. It indicates that natural gas inclusion is a kind of thermal hydrocarbon fluid formed within the basin. Method of opening inclusion by heating was used to analyze composition of fluid inclusion online, of which the maximal hydrocarbon gas content of fluid inclusion contained in veins is 2.4219 m3/t rock and the maximal C1/Σci ratio is 91%. Laser Raman spectroscopy (LRS) was used to analyze chemistry of individual fluid inclusion in which the maximal hydrocarbon gas content is 91.6% compared with little inorganic composition. Isotope analysis results of calcite veins show that they were deposited in fresh water, in which the δ13CPDB of calcite veins is from -5.75‰ to 15.23‰ andδ18OSMOW of calcite veins is from 21.33‰ to 21.67‰. Isotope results show thatδ13C1 PDB of natural gas fluid inclusion is from -21.36‰ to -29.06‰ and δDSMOW of that is from -70.89‰ to -111.03‰. It indicates that the gas of fluid inclusion formed from coal source rocks and it is the same as that of natural gas of Mizhi gas reservoir. Results of TL dating show that time of calcite vein is (32.4±3.42)×104 a, which is thought to be formation time of gas inclusion. It indicated that natural gas inclusion contained in calcite veins recorded natural gas leakage from Mizhi gas reservoir through the Central Fault Belt due to Himalayan tectonic movement.

  8. In situ Sr isotope analysis of apatite by LA-MC-ICPMS: constraints on the evolution of ore fluids of the Yinachang Fe-Cu-REE deposit, Southwest China

    Science.gov (United States)

    Zhao, Xin-Fu; Zhou, Mei-Fu; Gao, Jian-Feng; Li, Xiao-Chun; Li, Jian-Wei

    2015-10-01

    Apatite is a ubiquitous accessory mineral in a variety of rocks and hydrothermal ores. Strontium isotopes of apatite are well known to retain petrogenetic information and have been widely used to investigate the origin of igneous rocks, but such attempts have rarely been made to constrain ore-forming processes of hydrothermal systems. We here report in situ LA-MC-ICPMS Sr isotope data of apatite from the ~1660-Ma Yinachang Fe-Cu-REE deposit, Southwest China. The formation of this deposit was coeval to the emplacement of regionally distributed doleritic intrusions within a continental-rift setting. The deposit has a paragenetic sequence consisting of sodic alteration (stage I), magnetite mineralization (stage II), Cu sulfide and REE mineralization (stage III), and final barren calcite veining (stage IV). The stage II and III assemblages contain abundant apatite, allowing to investigate the temporal evolution of the Sr isotopic composition of the ore fluids. Apatite of stage II (Apt II) is associated with fluorite, magnetite, and siderite, whereas apatite from stage III (Apt III) occurs intimately intergrown with ankerite and Cu sulfides. Apt II has 87Sr/86Sr ratios varying from 0.70377 to 0.71074, broadly compatible with the coeval doleritic intrusions (0.70592 to 0.70692), indicating that ore-forming fluids responsible for stage II magnetite mineralization were largely equilibrated with mantle-derived mafic rocks. In contrast, Apt III has distinctly higher 87Sr/86Sr ratios from 0.71021 to 0.72114, which are interpreted to reflect external radiogenic Sr, likely derived from the Paleoproterozoic strata. Some Apt III crystals have undergone extensive metasomatism indicated by abundant monazite inclusions. The metasomatized apatite has much higher 87Sr/86Sr ratios up to 0.73721, which is consistent with bulk-rock Rb-Sr isotope analyses of Cu ores with 87Sr/86Sri from 0.71906 to 0.74632. The elevated 87Sr/86Sr values of metasomatized apatite and bulk Cu ores indicate

  9. Generation and evolution of hydrothermal fluids at Yellowstone: Insights from the Heart Lake Geyser Basin

    Science.gov (United States)

    Lowenstern, J. B.; Bergfeld, D.; Evans, William C.; Hurwitz, S.

    2012-01-01

    We sampled fumaroles and hot springs from the Heart Lake Geyser Basin (HLGB), measured water and gas discharge, and estimated heat and mass flux from this geothermal area in 2009. The combined data set reveals that diverse fluids share an origin by mixing of deep solute-rich parent water with dilute heated meteoric water, accompanied by subsequent boiling. A variety of chemical and isotopic geothermometers are consistent with a parent water that equilibrates with rocks at 205°C ± 10°C and then undergoes 21% ± 2% adiabatic boiling. Measured diffuse CO2 flux and fumarole compositions are consistent with an initial dissolved CO2 concentration of 21 ± 7 mmol upon arrival at the caldera boundary and prior to southeast flow, boiling, and discharge along the Witch Creek drainage. The calculated advective flow from the basin is 78 ± 16 L s−1 of parent thermal water, corresponding to 68 ± 14 MW, or –1% of the estimated thermal flux from Yellowstone. Helium and carbon isotopes reveal minor addition of locally derived crustal, biogenic, and meteoric gases as this fluid boils and degasses, reducing the He isotope ratio (Rc/Ra) from 2.91 to 1.09. The HLGB is one of the few thermal areas at Yellowstone that approaches a closed system, where a series of progressively boiled waters can be sampled along with related steam and noncondensable gas. At other Yellowstone locations, steam and gas are found without associated neutral Cl waters (e.g., Hot Spring Basin) or Cl-rich waters emerge without significant associated steam and gas (Upper Geyser Basin).

  10. Advances in research of sulphide ore textures and their implications for ore genesis

    Institute of Scientific and Technical Information of China (English)

    GU Lianxing; ZHENG Yuanchuan; TANG Xiaoqian; WU Changzhi; HU Wenxuan

    2006-01-01

    Important advances in research of sulphide ore textures in recent years have deepened our understanding of ore genesis of related mineral deposits. Pressure solution of sulphide minerals has been suggested as a mechanism for remobilization of ore materials,whereas pressure solution of the gangues is believed to raise the grade of the primary ores. We have known that precipitation of base metal sulphides from fluids prefers crystal and crack surfaces of pyrite to form overgrowth. Therefore, pyrite-bearing embryo beds in a sedimentary sequence can be acted as effective crystal seed beds and are favorable for fluid overprinting to form huge statabound deposits. Texture studies of various sulphides can be used to interpret the entire history of sedimentation, diagenesis, deformation and metamorphism of the ores. The study of chalcopyrite disease in sphalerite has brought about the idea of zone refining, and given a new explanation to metal zonation in massive sulphide deposits. Ductile shearing of sulphide ores may form ore mylonites, which will become oreshoots enriched in Cu, Au and Ag during late-stage fluid overprinting. Despite that various modern analytical techniques are being rapidly developed, ore microscopy remains to be an unreplaceable tool for ore geologists. Combined with these modern techniques, this tool will help accelerate the development of theories on ore genesis.

  11. Fluid and gasmigration in the southwestern part of the Lower Saxony basin

    Energy Technology Data Exchange (ETDEWEB)

    Lueders, V.; Plessen, B.; Sippel, J. [GeoForschungsZentrum Potsdam (Germany)

    2008-10-23

    Lower Carboniferous and Upper Jurassic sedimentary rocks from wells of the southwestern part of the Lower Saxony Basin (LSB) show locally anomalous maturity reaching 4.5% VRr. The reason for this high maturity is discussed controversy. It may either be related to the intrusions of supposed Late Cretaceous igneous plutons in the area of Bramsche and Vlotho or is explained by models involving deep burial during Early Cretaceous times and uplift during Late Cretaceous/Tertiary times. A fault-slip analysis covering outcrops within the LSB and along the Osning Lineament (OL) has been performed and showed that the area was affected by a stress state with a horizontal N-S- to NE-SW-directed maximum compression ({sigma}1) and a low stress ratio (R=({sigma}2-{sigma}3)/({sigma}1-{sigma}3)) which induced reverse and strike-slip faulting. The regional paleostress field can be related to the Late Cretaceous-Cenozoic intraplate compressional deformation that affected the Alpine foreland as a result of the Alpine orogeny Other stress fields estimated in the study area are much less prevalent. Tectonic activity induced the migration of fluids and let to precipitation of quartz and calcite on veins, fissures and slickensides. Calcite mostly precipitated from local formation waters that were in close equilibrium with the host rocks rather than being derived from a large scale circulating hydrothermal system. Fluid inclusions studies in hydrothermal minerals from wells and outcrops in the study area yield migration of differently composed fluids and gases during stages of burial and uplift. In the vicinity of supposed intrusions the migration of hot fluids (>200 C) is recorded in quartz mineralization that is hosted by Upper Carboniferous to Cretaceous sediments. The salinity of the studied fluid inclusions is highly variable suggesting that different fluid reservoirs were drained. However, fluid entrapment often occurred along with the entrapment of gas mixtures with variable

  12. Multi-origin alkanes related to CO2-rich, mantle-derived fluid in Dongying Sag, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the newly obtained carbon isotope data for the natural gas, a pilot study of multiple-sourced alkanes related to the mantled-derived fluid is presented. The carbon isotope values of alkanes in the Dongying Sag possess thefea tures indicating a general organic origin. However, there are two sub-populations in the isotopic data set, which reflect two specific types of origins. In gene ral, the sub-population with high δ13CCH4 values is related to the CO2-rich, mantle-derived fluid, and it is distributed in the belts where mantle-derived fluid flow and basic volcanic activities have occurred. Geological and geochemical studies demonstrate that this variation of methane carbon isotope values in the Dongying Sag is unrelated with the basin bury and thermal histories, types of source rocks, and reactions between basin fluid and rocks. Mixing of mantle-derived fluid and organic sourced hydrocarbons is probably the cause for the variation .

  13. Environment of ore deposition in the Creede mining district, San Juan Mountains, Colorado; Part IV, source of fluids, from oxygen, hydrogen, and carbon isotope studies

    Science.gov (United States)

    Bethke, P.M.; Rye, R.O.

    1979-01-01

    also oxygen shifted meteoric waters but were some 40 per mil lower in deuterium content than the sphalerite and illite/chlorite waters.We propose that the quartz fluids entered the vein system from reservoirs beneath the mountainous areas to the north in the vicinity of the present Continental Divide, but that the sphalerite and illite/chlorite fluids entered the vein system from a topographically low area to the south along the structural moat of the Creede caldera. The difference in delta D between the two meteoric waters may reflect differences in altitude of the recharge areas for the two reservoirs or may be clue to isotopic evolution of the closed-basin lake and interstitial waters in the moat surrounding the Creede caldera.

  14. Intermediate sulfidation epithermal mineralization of No. 4 anomaly of Golojeh deposit (N. Zanjan based on mineralography, alteration and ore fluid geochemistry features

    Directory of Open Access Journals (Sweden)

    Behzad Mehrab

    2014-04-01

    contents of galena, sphalerite and minor chalcopyrite and tennantite, low to moderate temperature and salinity of ore-bearing fluid, low depth of mineralization and Fe–bearing sphalerite features at the No. 4 anomaly of Golojeh deposit, are similar to those of intermediate sulfidation (IS epithermal base and precious metals vein–type deposit that probably might be related to Cu–Au porphyry system in depth.

  15. Geochemistry of Rare Earth Elements in Xikeng Ag-Pb-Zn Ore Deposit, South Anhui, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, a comparative study is done on the geochemical charateristics of REE in ore, ore-hosted rocks of Lantian group, granite related to ore deposit, and altered rocks for tracing origin of ore-forming materials. The result indicates that the ore-forming fluid and ore-forming materials for Xikeng silver-polymetallic ore deposit were derived from Yixian granite's magmatic activity. Water-rock reaction of the hydrothermal fluid with the carbonate-rich stratum led the altered rock to relatively enrich in HREE.

  16. Geometry and subsidence history of the Dead Sea basin: A case for fluid-induced mid-crustal shear zone?

    Science.gov (United States)

    ten Brink, U.S.; Flores, C.H.

    2012-01-01

    Pull-apart basins are narrow zones of crustal extension bounded by strike-slip faults that can serve as analogs to the early stages of crustal rifting. We use seismic tomography, 2-D ray tracing, gravity modeling, and subsidence analysis to study crustal extension of the Dead Sea basin (DSB), a large and long-lived pull-apart basin along the Dead Sea transform (DST). The basin gradually shallows southward for 50 km from the only significant transverse normal fault. Stratigraphic relationships there indicate basin elongation with time. The basin is deepest (8-8.5 km) and widest (???15 km) under the Lisan about 40 km north of the transverse fault. Farther north, basin depth is ambiguous, but is 3 km deep immediately north of the lake. The underlying pre-basin sedimentary layer thickens gradually from 2 to 3 km under the southern edge of the DSB to 3-4 km under the northern end of the lake and 5-6 km farther north. Crystalline basement is ???11 km deep under the deepest part of the basin. The upper crust under the basin has lower P wave velocity than in the surrounding regions, which is interpreted to reflect elevated pore fluids there. Within data resolution, the lower crust below ???18 km and the Moho are not affected by basin development. The subsidence rate was several hundreds of m/m.y. since the development of the DST ???17 Ma, similar to other basins along the DST, but subsidence rate has accelerated by an order of magnitude during the Pleistocene, which allowed the accumulation of 4 km of sediment. We propose that the rapid subsidence and perhaps elongation of the DSB are due to the development of inter-connected mid-crustal ductile shear zones caused by alteration of feldspar to muscovite in the presence of pore fluids. This alteration resulted in a significant strength decrease and viscous creep. We propose a similar cause to the enigmatic rapid subsidence of the North Sea at the onset the North Atlantic mantle plume. Thus, we propose that aqueous fluid flux

  17. Fluid transport by solitary waves along growing faults. A field example from the South Eugene Island Basin, Gulf of Mexico

    Science.gov (United States)

    Revil, A.; Cathles, L. M.

    2002-09-01

    The Red Fault system is one of the main growth faults found in the South Eugene Island Basin, a salt withdrawal minibasin located offshore Louisiana, in the Gulf of Mexico. This fault system corresponds to a lateral boundary between fluid overpressured compartments. In addition, there is a set of observations indicating that the Red Fault system exhibits rapid episodic migration of fluids. This fault represents an example of preferential pathway for the upward episodic migration of overpressured hydrocarbons from deep, heavily pressured, compartments on time scales of years. The migrations of fluids into active growing faults could take the form of propagating surges (solitary waves) that propagate upward along the fault planes in a wave-like manner at km/yr. Solitary waves represent a very efficient mechanism for the upward transport of fluids along growth faults in sedimentary basins generating its own permeability. In addition, this mechanism is compatible with the fact that the fault plane is observed to sustain a static pore fluid pressure difference between its two sides. The propagation of solitary waves in active growth faults appears as a fundamental mechanism to understand the nature of upward fast migration of fluids along active growth faults in compartimentalized sedimentary basins.

  18. Study on Fluid Inclusions of Copper and Nickel Ore Deposit in East Hebei Province%冀东孤山子铜镍矿床流体包裹体

    Institute of Scientific and Technical Information of China (English)

    李昌存; 何佳; 杨东鹏; 何凤广

    2014-01-01

    孤山子超镁铁质岩体是冀东地区重要的磁铁矿源之一,同时也拥有较好的铜镍矿床的成矿条件。流体包裹体的研究表明,该铜镍矿床的流体包裹体主要有3种类型:气液两相包裹体(个别为纯液相包裹体)、富CO2三相包裹体和纯气相包裹体。孤山子铜镍矿床的成矿流体属于中低温、中盐度和中低密度的酸性流体,形成深度约为85.~98.km,成矿流体压力约为106~138 M Pa。%Gushanzi ultrabasic rock mass is one of the important source of magnet in Hebei eastern ,w hich has good metallogenic conditions of copper -nickel .Studies on fluid inclusion show that there are three major types of fluid inclusion :gas-liquid inclusions (individual pure liquid inclusions ) ,rich CO2 three-phase inclusions and pure gas inclusions .Gushanzi copper -nickel deposit ore-forming fluid belongs to a-cidic fluid of mid -low temperature ,middle salinity and mid -low density ,w hich formed under the depth of about 8 5. ~ 9 8. km ,and the pressure of ore -forming fluid was between 106 and 138 Mpa .

  19. Origin of fluid inclusion water in bedded salt deposits, Palo Duro Basin, Texas

    International Nuclear Information System (INIS)

    Salt horizons in the Palo Duro Basin being considered for repository sites contain fluid inclusions which may represent connate water retained in the salt from the time of original salt deposition and/or external waters which have somehow penetrated the salt. The exact origin of this water is important to the question of whether or not internal portions of the salt deposit have been, and are likely to be, isolated from the hydrosphere for long periods of time. The 18O/16O and D/H ratios measured for water extracted from solid salt samples show the inclusions to be dissimilar in isotopic composition to meteoric waters and to formation waters above and below the salt. The fluid inclusions cannot be purely external waters which have migrated into the salt. The isotope data are readily explained in terms of mixed meteoric-marine connate evaporite waters which date back to the time of deposition and early diagenesis of the salt (>250 million years). Any later penetration of the salt by meteoric waters has been insufficient to flush out the connate brines

  20. Characters of fluid inclusions in quartz veins in pyroclastic rock of Budate Group, Hailar Basin

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-tao; LIU Li; GAO Yu-qiao; SHAO Hong-mei; SHEN Guang-zheng

    2004-01-01

    It was adopted that the fluorescence microscope, Gas-Flow Heating/Freezing System, Laser-Raman Spectroscopy, etc. are the multimedia techniques for analysing fluid inclusions of quartz veins in Budate Group, Hailar Basin.The results show that fluid inclusions in quartz veins are small (1 ~5 μm) monophase, two-phase (liquid+vapour)aqueous inclusions; the two-phase aqueous inclusions homogeniese to the liquid phase between 120 ~ 180℃, two Laser-Raman Spectroscopy show that both gas phase are enriched in CH4 (94.50% ~99.25% ) and C6H6 (0.75% ~2.70%), under these conditions, inclusions may have come from juvenile fliud followingly the quartz veins formation.While the quartz veins exhibiting different striking luminescence has been proved by cathodoluminescence, it would be belong to secondary hydrocarbon inclusions. The oil inclusions of this stage represent mainly the large scale of oil accumulation, located within the quartz microfracture.

  1. 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

    Science.gov (United States)

    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

  2. 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

    Science.gov (United States)

    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

  3. 青海省兴海县铜峪沟铜矿床成矿物质和流体来源的地球化学探讨%Geochemistry Constraint on Ore-forming Material and Ore-forming Fluids of Tongyugou Copper Deposit in Xinghai County,Qinghai Province

    Institute of Scientific and Technical Information of China (English)

    曾小华; 周宗桂

    2014-01-01

    青海铜峪沟铜矿床位于祁漫塔格-鄂拉山成矿亚带鄂拉山多金属矿带东南段。通过对铜峪沟铜矿床的矿石矿物微量元素地球化学研究及矿石矿物的稳定同位素研究,探讨该矿床的成矿物质及流体来源,确定矿床的成因。从测试结果来看,稀土元素配分模式为轻稀土较富集、重稀土亏损、分馏程度较高、Eu中度-强烈亏损,显示矿石物质来源为混合来源;硫同位素δ34 S测试结果全为负值,属轻硫型,总体上揭示出硫主要来自地层的沉积硫;铅同位素测试数据表明矿石铅部分来自沉积成岩阶段,部分与印支期造山运动有关,表明成矿物质混合来源的特征,富成矿流体在成矿之前存在均一化过程。氢、氧、硅同位素研究表明成矿热液为原生岩浆水和变质热液水,反映成矿物质来源与岩浆热液活动有关。通过研究认为,铜峪沟铜矿床为矽卡岩型铜矿床。%Tongyugou copper deposit is located in the southeast segment of the Elashan polymetallic belt in Qimantage-Elashan ore-forming subzone.Based on the trace element geochemistry and the stable isotopes of Tonyugou copper deposit,this paper studied the source of ore-forming material and ore-forming fluids,identified the genesis of Tongyugou copper deposit.From the test results,the rare earth element distribution patterns are approximately consistent,the REE patterns are enriched in LREE and are depleted in HREE with high fraction-ation and negative Eu anomaly,demonstrating that the ore material comes from multi-source;sulfur isotope compositions δ34S measurement are full-negative,belong to light sulfur type,revealing that the whole S was from the sedimentary sulfur;the demographics of Pb isotopic compositions showing that the lead was mainly from the ore deposition diagenetic stage,and partly from the Indosinian orogeny,which is closely related to Indo-Chinese orogenic movement

  4. 青海东昆仑阿斯哈金矿Ⅰ号脉成矿流体地球化学特征和矿床成因%Geochemical Features of Ore-Forming Fluids and Metallogenesis of Vein Ⅰ in Asiha Gold Ore Deposit,Eastern Kunlun,Qinghai Province

    Institute of Scientific and Technical Information of China (English)

    李碧乐; 沈鑫; 陈广俊; 杨延乾; 李永胜

    2012-01-01

    The Asiha gold ore deposit is located in the east part of the middle uplifted basement and granitic belt which is one important gold and ferro-polymetallic metallogenic belt in eastern Kunlun. The Early Indosinian diorite and biotite granite are the main ore-hosting rocks, while the NNE and NW-trending faults are major ore-bearing structures in the mine area. Vein I is one of the major auriferous veins, and is closely related to the minette spatially. Fluid inclusions in quartz crystals can be classified into aqueous two-phase and CO2-rich three-phase inclusion. Salinities of fluid inclusions contents of NaCl range from 1. 83% to 8. 13%, densities range from 0. 69 to 0. 87 g/cm3, and homogenization temperatures range from 155. 3 'C to 425. 6 °C, In mineralization stage I , fluid inclusions are characterized by low salinity, high-temperature, and CO2-rich. In mineralization stage Ⅱ , CO2-rich fluid inclusions and gas-liquid two-phase inclusions coexist, which show the immiscibility or boiling characterized by CO2 escaping, and resulted in salinity increasing of the residual fluid. Fluid inclusions in mineralized stage Ⅲ are the gas-liquid two-phase inclusions. Charteristics of fluid inclusions, accompanied with H, O, S isotopic compositions, indicates that the ore-forming fluid is mainly mantle-derived and additional meteoric water in the late stage. By analyzing of Laser Raman spectrum, the gas-phase in fluid inclusions chiefly make up of CO2 ,CH4 and N2. According to the diagram of isochore, the ore-forming pressure can be calculated to almost 98 - 132 MPa,the ore-forming depth ranges from 8. 16 -9.58 km. By contrast to other typical orogenic gold deposits, A conclusion can be safely darwn that Asiha gold deposit belongs to the mesozonal orogenic gold deposit, and the gold mineralization occured in the transition period from compression to extension tectonic environment during intro-continental orogenic movement in Early Indosinian.%阿斯哈金矿位于东

  5. Evidence for episodic expulsion of hot fluids along faults near diapiric structures of the Yinggehai Basin, South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Xinong Xie; Sitian Li [China University of Geosciences, Wuhan (China). College of Earth Resources; Weiliang Dong; Zhongliang Hu [China Offshore Oil Nanhai West Corp., Zhanjiang (China)

    2001-06-01

    Diapiric structures are well developed and occur in most of the central part of the Yinggehai Basin, on the western side of the South China margin. A strong thermal anomaly due to hot fluid flows occurs in the diapiric zone, as evidenced from vitrinite reflectance (R{sub o}), clay mineral transformation, and fluid inclusion homogenization temperatures. This anomaly results from hydrothermal fluid flow along vertical faults from overpressured compartments into the overlying Late Miocene and Quaternary sand-rich layers. The magnitude of thermal anomaly is related not only to the distance to which the vertical fault is hydraulically open, but the permeability of rocks interconnected with the faults. Intense heat transfer for convection of fluids occurs in the sand-rich intervals adjacent to vertical faults. Abnormal organic-matter maturation, together with rapid transformation of clay minerals, which occurs at certain intervals within the present-day normally pressured system and normal conductive temperatures in a diapir, can be used to identify palaeo high pressure zones. Abnormal high temperatures measured from a drill-stem test in a diapir can be inferred to be the results of recent expulsion of hydrothermal fluid flow. The results of this study suggest that thermal fluid expulsion along faults plays an important role in the modification of thermal regimes, the enhancement of organic-matter maturation, and rapid transformation of clay minerals, as well as the accumulation of hydrocarbons in diapiric structures of the Yinggehai Basin, South China Sea. (author)

  6. Thermal evolution, fluid flow, and fracture development related to the structuration of the South Pyrenean Foreland Basin

    Science.gov (United States)

    Crognier, N.; Hoareau, G.; Aubourg, C.; Branellec, M.; Dubois, M.; Lahfid, A.; Lacroix, B.; Labaume, P.; Suarez-Ruiz, I.

    2015-12-01

    The E-W trending South Pyrenean Foreland Basin, formed during the upper Cretaceous and the early Miocene due to the collision between Iberian and European plates, is filled by marine to continental deposits affected by a set of successive southvergent thrusts. In order to constrain the links between fracture development, thermal regime, and fluid flow in the basin, we estimated temperatures of formation and C-O isotope signatures of fracture-filling minerals (veins), maximum paleo-temperatures of sediments, and the timing and orientation of major fracture sets. The isotopic composition of 150 veins and sediment samples has been measured. Peak temperatures of 100 bulk rocks and veins have been estimated, using Raman spectroscopy, vitrinite reflectance, fluid inclusion microthermometry and mass-47 clumped isotopes. The orientation of ~5000 joints and veins has been used to link major tectonic events to fracture development. Most primary fluid inclusions show moderate salinities (~2.5 wt%), compatible with connate or evolved meteoric waters. Fluids were generally in thermal and isotopic equilibrium with host sediments, suggesting a low fluid-rock ratio, and thus a limited impact of fractures on fluid-flow. Peak temperatures (T max) decrease southward, from ~240°C in Cretaceous to Eocene sediments close to the axial zone, to ~60°C. In a same location dominant compaction joints were mineralized close to T max, ~40°C higher than tectonic shear veins. All fracture orientations were likely controlled by Pyrenean shortening. Genetic relationships between fracture sets are currently under investigation. Finally, temperatures of 240°C measured in Eocene sediments cannot be explained by balanced cross sections using geothermal gradient expected in foreland basins (20-25°C/km). 1D thermal modeling is being performed to explain this thermal anomaly, which could result from high heat flow following mid-Cretaceous extension, the ingress of hot fluids, or undocumented tectonic

  7. Assessment of the impact of moving fluids on the regional thermal field for the area of Brandenburg (North German Basin)

    Science.gov (United States)

    Noack, V.; Scheck-Wenderoth, M.; Cacace, M.; Lewerenz, B.

    2012-04-01

    We present results from numerical simulations of the 3D thermal field for the area of Brandenburg in the North German Basin. The study area encompasses a part of the basin centre in the north, whereas to the south the basin margin is enclosed. Starting with Permocarboniferous volcanic rocks the basin fill is represented by Permian to Cenozoic sediments. A thick layer of mobilized salt (Zechstein, Upper Permian) generated elevated structures such as salt pillows and diapirs. Especially where diapirs pierce their overburden, the overlying deposits are strongly influenced in their thickness and distribution. This special configuration of the Zechstein salt is relevant for the thermal calculations due to the fact that salt has a distinctly higher thermal conductivity than the surrounding sediments and is impermeable to fluid flow. Therefore, the Zechstein salt acts as a conductive chimney for heat and a hydraulic decoupling horizon between the Pre-Permian and the Mesozoic-Cenozoic strata. The latter are characterized by two further quasi-impervious sediment complexes, the Rupelian-clay and the Muschelkalk. These two divide the Post-Permian strata in three main aquifer systems: the Buntsandstein, Keuper to Pre-Rupelian and the Post-Rupelian complex. Based on results from purely conductive modelling we additionally analyse the influence of moving fluids on the shallow temperature field above the Zechstein salt. Therefore coupled fluid flow and heat transfer numerical simulations are carried out to investigate the hydrothermal field. The 3D simulations for the heat transport processes are based on the finite element method. The results indicate that the distribution of thermal conductivities in the basin fill controls the short-wavelength pattern of the temperature distribution whereas the long wavelength pattern results from interaction between the highly conductive crust and low conductive sediments. Furthermore, the results reveal that the shallow temperature field

  8. On the role of buoyancy force in the ore genesis of SEDEX deposits: Example from Northern Australia

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Finite element modeling on a highly conceptualized 2-D model of fluid flow and heat transport is un-dertaken to simulate the paleo-hydrological system as if the Mount Isa deposits were being formed in the Mount Isa basin, Northern Australia, and to evaluate the potential of buoyancy force in driving ba-sin-scale fluid flow for the formation of sedimentary-exhalative (SEDEX) deposits. Our numerical case studies indicate that buoyancy-driven fluid flow is controlled mainly by the fault penetration depth and its spatial relation with the aquifer. Marine water recharges the basin via one fault and flows through the aquifer where it is heated from below. The heated metalliferous fluid discharges to the basin floor via the other fault. The venting fluid temperatures are computed to be in the range of 115 to 160℃, with fluid velocities of 2.6 to 4.1 m/year over a period of 1 Ma. These conditions are suitable for the formation of a Mount Isa-sized zinc deposit, provided a suitable chemical trap environment is present. Buoyancy force is therefore a viable driving mechanism for basin-scale ore-forming hydrothermal fluid migration, and it is strong enough to lead to the genesis of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia.

  9. On the role of buoyancy force in the ore genesis of SEDEX deposits: Example from Northern Australia

    Institute of Scientific and Technical Information of China (English)

    YANG JianWen; FENG ZuoHai; LUO XianRong; CHEN YuanRong

    2009-01-01

    Finite element modeling on a highly conceptualized 2-D model of fluid flow and heat transport is un-dertaken to simulate the paleo-hydrological system as if the Mount Ise deposits were being formed in the Mount Isa basin, Northern Australia, and to evaluate the potential of buoyancy force in driving ba-sin-scale fluid flow for the formation of sedimentary-exhalative (SEDEX) deposits. Our numerical case studies indicate that buoyancy-driven fluid flow is controlled mainly by the fault penetration depth and its spatial relation with the aquifer. Marine water recharges the basin via one fault and flows through the aquifer where it is heated from below. The heated metalliferous fluid discharges to the basin floor via the other fault. The venting fluid temperatures are computed to be in the range of 115 to 160℃, with fluid velocities of 2.6 to 4.1 m/year over a period of 1 Ma. These conditions are suitable for the formation of a Mount Isa-sized zinc deposit, provided a suitable chemical trap environment is present. Buoyancy force is therefore a viable driving mechanism for basin-scale ore-forming hydrothermal fluid migration, and it is strong enough to lead to the genesis of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia.

  10. Fluid evolution and mineralogy of Mn-Fe-barite-fluorite mineralizations at the contact of the Thuringian Basin, Thüringer Wald and Thüringer Schiefergebirge in Germany

    Directory of Open Access Journals (Sweden)

    Majzlan Juraj

    2016-02-01

    Full Text Available Numerous small deposits and occurrences of Mn-Fe-fluorite-barite mineralization have developed at the contact of the Thuringian Basin, Thüringer Wald and Thüringer Schiefergebirge in central Germany. The studied mineralizations comprise the assemblages siderite+ankerite-calcite-fluorite-barite and hematite-Mn oxides-calcite-barite, with the precipitation sequence in that order within each assemblage. A structural geological analysis places the origin of the barite veins between the Middle Jurassic and Early Cretaceous. Primary fluid inclusions contain water vapour and an aqueous phase with NaCl and CaCl2 as the main solutes, with salinities mostly between 24–27 mass. % CaCl2 eq. Th measurements range between 85 °C and 160 °C in barite, between 139 °C and 163 °C in siderite, and between 80 °C and 130 °C in fluorite and calcite. Stable isotopes (S, O point to the evaporitic source of sulphur in the observed mineralizations. The S,C,O isotopic compositions suggest that barite and calcite could not have precipitated from the same fluid. The isotopic composition of the fluid that precipitated barite is close to the sea water in the entire Permo–Mesozoic time span whereas calcite is isotopically distinctly heavier, as if the fluids were affected by evaporation. The fluid evolution in the siliciclastic/volcanic Rotliegend sediments (as determined by a number of earlier petrological and geochemical studies can be correlated with the deposition sequence of the ore minerals. In particular, the bleaching of the sediments by reduced Rotliegend fluids (basinal brines could be the event that mobilized Fe and Mn. These elements were deposited as siderite+ankerite within the Zechstein carbonate rocks and as hematite+Mn oxides within the oxidizing environment of the Permian volcanic and volcanoclastic rocks. A Middle-Jurassic illitization event delivered Ca, Na, Ba, and Pb from the feldspars into the basinal brines. Of these elements, Ba was

  11. Characteristics of Fluid Inclusions in Jiama Copper-Pollymetallic Ore Deposit, Tibet and Its Geological Significance%西藏甲玛铜多金属矿床流体包裹体特征及地质意义

    Institute of Scientific and Technical Information of China (English)

    李永胜; 赵财胜; 吕志成; 严光生; 甄世民

    2011-01-01

    The recently discovered Jiama super large copper-polymetallic deposit is located in the middle section of Gangdese metallogenic belt, Tibet. Systematic studies including petrography, microthermometry, laser Raman microprobe and SEM/EDS were carried out on the primary fluid inclusions in metallogentic granite and major ore bodies. The analytical results show that dominant fluid inclusions from skarn ore related to metallogensis include liquid-rich, gas-rich two-phase and daughterminerals bearing polyphase types. Homogenization temperatures of the fluid inclusions range from 225 ℃ to 500 ℃. The average of the salinities of ore-forming fluid is 36. 2% NaCleq and the densities vary from 0.89 to 0.98 g/cm3. The ore-forming fluids belong to NaCl - H2O type characterized by highmoderate temperature, high salinity, low density and strong reduction. Besides H2O, the gas compositions are immiscible system rich in CH4, H2S, CO2 and N2 etc. The occurrence of organic matter, such as CH4, C2H4 and C3H6, suggests that the ore-forming materials were formed in a reduced environment. Based on estimation of mineralization pressure and the relationship between pressure and depth in fracture zones, the mineralization depth is considered to be at 2.2 - 8.3 km. The analytical results of hydrogen and oxygen isotopic elements show that ore-forming fluids are mainly derived from magmatic water mixed with meteoric water later. The coexistence of daughter-minerals bearing multiphase inclusions and those liquid-and gas-rich inclusions with different filling degrees, together with their similar homogenization temperatures and much different salinities, indicates that ore-forming fluids had experienced boiling.%甲玛矿床是位于西藏冈底斯成矿带中段的超大型铜多金属矿床.成矿相关岩体和主矿体中的流体包裹体岩相学、显微测温、激光拉曼探针及扫描电镜/能谱分析结果表明:与成矿有关的流体包裹体主要有富液相、富气相

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Etminan, H.; Hoffmann, C.F. (Bureau of Mineral Resources, Canberra (Australia))

    1989-01-01

    Biomarkers in fluid inclusion s 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 hydrocarbonas 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.

  14. Sedimentary exhalative nickel-molybdenum ores in south China

    Science.gov (United States)

    Lott, D.A.; Coveney, R.M., Jr.; Murowchick, J.B.; Grauch, R.I.

    1999-01-01

    Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

  15. 吉林荒沟山金矿床成矿流体特征%Geochemical Characteristics of Ore-Forming Fluid in Huanggoushan Gold Deposit,Jilin Province

    Institute of Scientific and Technical Information of China (English)

    周向斌; 李剑锋; 王可勇; 梁一鸿; 张淼; 韦烈民; 王志高

    2016-01-01

    荒沟山金矿床为吉南老岭金-多金属成矿带内较具代表性矿床之一,产于元古宇老岭群珍珠门组地层之中,受韧性剪切带构造控制。按地质特征、矿物组合及矿脉之间的穿切关系,将荒沟山金矿床热液成矿作用划分为Ⅰ黄铁矿-毒砂-石英阶段和Ⅱ晚期辉锑矿-乳白色石英两个阶段。系统的流体包裹体岩相学及显微测温研究表明:Ⅰ阶段石英中发育含 CO 2三相、碳质及气液两相3种类型的原生流体包裹体,成矿流体属不混溶的中低温、低盐度 NaCl-H 2 O-CO 2体系热液,在成矿过程中发生过不混溶作用而导致金等有用元素沉淀富集;Ⅱ阶段石英颗粒中主要发育气液两相包裹体,成矿流体属均匀的 NaCl-H 2 O 体系热液。碳、氢、氧同位素研究表明,Ⅰ阶段成矿流体主要来源于岩浆热液,Ⅱ阶段流体除继承早阶段的热液外,还有大气降水的混入;δD 和δ13 CV-PDB 值分析结果证明两个成矿阶段流体均与地层发生过较强的水岩反应。矿床成因属于中温岩浆热液矿床。%Occurred in Zhenzhumen Formation of Laoling Group of Proterozoic Era and controlled by ductile shear belt,the Huanggoushan gold deposit is one of the most representative deposits in Laoling gold-polymetallic metallogenic belt in southern Jilin Province.Based on the geological characteristics,mineral assemblage and the crosscutting relationship between different kinds of veins,the hydrothermal mineralization processes can be divided into two main stages,namely,stageⅠpyrite arseno-pyrite quartz and stageⅡ later stibnite-milky quartz.Systematic study on petrography and microthermometry of fluid inclusions shows that quartz of Stage Ⅰcontains three types of primary fluid inclusions,which are CO 2 bearing three phases,carbonic and aqueous two phases inclusions respectively,and the ore forming fluid is of medium to low temperature and low salinity NaCl-H 2 O-CO 2 kind of

  16. Drilling the centre of the Thuringian Basin, Germany, to decipher potential interrelation between shallow and deep fluid systems

    Science.gov (United States)

    Kukowski, Nina; Totsche, Kai Uwe; Abratis, Michael; Habisreuther, Annett; Ward, Timothy; Influins Drilling-Team

    2014-05-01

    To shed light on the coupled dynamics of near surface and deep fluids in a sedimentary basin on various scales, ranging from the pore scale to the extent of an entire basin, is of paramount importance to understand the functioning of sedimentary basins fluid systems and therefore e.g. drinking water supply. It is also the fundamental goal of INFLUINS (INtegrated FLuid dynamics IN Sedimentary basins), a research initiative of several groups from Friedrich-Schiller University of Jena and their partners. This research association is focusing on the nearby Thuringian basin, a well confined, small intra-continental sedimentary basin in Germany, as a natural geo laboratory. In a multidisciplinary approach, embracing different fields of geophysics like seismic reflection profiling or airborne geomagnetics, structural geology, sedimentology, hydrogeology, hydrochemistry and hydrology, remote sensing, microbiology and mineralogy, among others, and including both, field-based, laboratory-based and computer-based research, an integral INFLUINS topic is the potential interaction of aquifers within the basin and at its rims. The Thuringian basin, which is composed of sedimentary rocks from the latest Paleozoic and mainly Triassic, is particularly suited to undertake such research as it is of relative small size, about 50 to 100 km, easily accessible, and quite well known from previous studies, and therefore also a perfect candidate for deep drilling. After the acquisition of 76 km seismic reflection data in spring 2011, to get as much relevant data as possible from a deep drilling at the cross point between two seismic profiles with a limited financial budget, an optimated core sampling and measuring strategy including partial coring, borehole geophysics and pump tests as well as a drill hole design, which enables for later continuation of drilling down to the basement, had been developed. Drilling Triassic rocks from Keuper to lower Buntsandstein was successfully realised down

  17. Ore-forming and Exploration Models of the Baguamiao Gold Deposit, Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Baguamiao superlarge gold deposit in Shaanxi Province is one of the typical cases in China that are hosted by sedimentary rocks. Explorers and researchers have discussed the gold mineralization enrichment conditions by studying sulphur, oxygen, carbon, silicon stable isotopes and mineralizing fluid features of the Baguamiao gold deposit and proposed a hydrothermal sedimentation-magmatic reconstructing gold mineralization model featuring multi-sources of ore-forming materials and multistage mineralizations. In addition, prospecting for "Baguamiao-type"gold deposits was started in the Fengtai Basin and a great number of important prospecting targets such as Tonglinggou, Simaoling, Guoansi and Dachaigou were discovered.

  18. Fault-Related CO2 Degassing, Geothermics, and Fluid Flow in Southern California Basins--Physiochemical Evidence and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Garven, Grant [Tufts University

    2015-08-11

    Our studies have had an important impact on societal issues. Experimental and field observations show that CO2 degassing, such as might occur from stored CO2 reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.

  19. Geology and isotopic composition of helium, neon, xenon and metallogenic age of the Jinding and Baiyangping ore deposits, northwest Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    薛春纪; 陈毓川; 王登红; 杨建民; 杨伟光; 曾荣

    2003-01-01

    Both the Jinding and Baiyangping ore deposits developed in the Lanping basin, which is a Mesozoic-Cenozoic terrestrial clastic sedimentary basin. Their occurrences can easily lead many people to compare them with the Pb-Zn deposit hosted in sedimentary rocks, such as Mississippian Valley-, Sedex- and sandstone-type Pb-Zn deposits. However, the Lanping basin developed in the settings of strong tectonic activity of the continental crust, which could cause an effective material exchange between the lower crust and the upper mantle. The orebodies are clearly tectonically controlled without syngenetic features, which probably represents a new type of the sedimentary rock-hosted Pb-Zn deposit. The isotopic compositions of noble gases in ore-forming fluids indicate that 2%-32% of helium (3He/4He = 0.19 Ra-1.97 Ra) is derived from the mantle, 50.1% of neon (20Ne/22Ne = 10.45-10.83; 21Ne/22Ne = 0.03) from the mantle, and considerable amount of xenon (129Xe/130Xe = 5.84-6.86; 134Xe/130Xe = 2.26-2.71) from the mantle, which show that mantle fluids played an important role in the ore formation. The ore-forming age of 67-60 Ma obtained by Re-Os and 40Ar-39Ar dating methods is later than the host rock, which is coeval with the Himalayan alkali magmatism of the mantle source and mantle-crust source. In this paper, the mineralization of the Jinding and Baiyangping ore deposits is considered to be related to the mantle fluids which move upward with the magma or along the deep faults, and mix with the meteoritic brine in the crust to result in large-scale deposition.

  20. Evolution of Ore-forming Fluids in the Anqing Copper-iron Deposit, Anhui Province, and Its Ore-forming Implications%安徽安庆铜铁矿床成矿流体演化特征及其成矿意义

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      安庆铜铁矿床是长江中下游成矿带内重要的矽卡岩型矿床之一。本文对该矿床中的成矿流体进行了系统研究,分析了成矿流体性质、来源及其演化过程,探讨了成矿机制。流体包裹体岩相学观察显示,矿床中的包裹体类型有Ⅰ型含子矿物三相包裹体(L+V+S)、Ⅱ型气液两相包裹体(L+V)及少量Ⅲ型气相包裹体(V);气成-高温热液期的透辉石与石榴子石中流体包裹体数量相对较少,以Ⅰ型包裹体为主;而热液期的石英与方解石中流体包裹体大量发育,以Ⅱ型包裹体为主。激光拉曼探针分析和流体包裹体显微测温结果表明,成矿流体可近似地看作不饱和的NaCl-H2O体系。从早矽卡岩阶段至碳酸盐阶段,成矿流体经历了从高温(456.1~578.1℃)、高盐度(39.37%~54.58% NaCleq)向低温(112.3~312.4℃)、低盐度(7.59%~31.75% NaCleq)的持续演化。演化过程中经历了流体沸腾作用和岩浆热液与大气降水的混合作用,其中,早矽卡岩阶段的水-岩作用、沸腾作用与矽卡岩成岩作用有关,水-岩作用,而石英-硫化物阶段的沸腾作用与混合作用可能是铜矿形成的重要机制。氢、氧同位素研究表明气成-高温热液期的成矿流体以岩浆水为主,而在热液期中石英-硫化物阶段至碳酸盐阶段大气降水在成矿流体中的比重逐渐增大。%Anqing copper-iron deposit is one of the most important skarn-type deposits along the Middle and Lower Yangtze River metallogenic belt. In this study, the ore-forming fluids of this deposit are systematically researched by analyzing their properties, and evolution, and discussing the ore-forming mechanism. The petrographic observation of fluid inclusions shows that inclusions of the deposit consist of I-type daughter mineral-bearing three-phase inclusions (L+V+S), II-type gas-liquid two-phase inclusions (L+V), and a few

  1. 新疆阿尔泰托莫尔特铁(锰)矿床成矿流体研究%A study of ore-forming fluids of Tuomoerte Fe-(Mn) deposit in Altay, Xinjiang

    Institute of Scientific and Technical Information of China (English)

    张志欣; 杨富全; 黄承科; 刘锋; 柴凤梅; 耿新霞

    2012-01-01

    托莫尔特铁(锰)矿床赋存于上志留统一下泥盆统康布铁堡组上亚组变质火山-沉积岩系中.矿床的形成经历了火山沉积期、岩浆热液叠加改造期和区域变质期,火山沉积期为铁和锰主要成矿期.火山沉积期石英中流体包裹体类型以气液两相包裹体为主,均一温度集中于170~300℃,峰值为190℃,流体的ω(NaClq)为3.23%~22.71%,密度为0.62~ 1.09 g/cm3,气相和液相成分表明成矿流体富含Na+、Cl和H2O,为中-低温、中-低盐度、中-低密度的H2O-NaCl体系.区域变质期石英中以发育含液体CO2包裹体为特征,完全均一温度介于210~523℃,w(NaCleq)为4.80%~11.33%,密度为0.85~1.05 g/cm3,气相和液相成分表明流体富含Na+、Cl、SO2-4、CO2、CH4、C2H6和N2,显示成矿流体为中-高温、中-低盐度、中-低密度的H2O-CO2-CH4-N2-NaCl体系.氢和氧同位素特征表明,火山沉积期成矿流体为海水和岩浆水的混合,区域变质期成矿流体主要为变质水混合深循环的大气降水.%The Tuomoerte Fe-(Mn) deposit occurs in metavolcanic-sedimentary sequence within the upper subforma-tion of Upper Silurian-Lower Devonian Kangbutiebao Formation. Field evidence and petrographic observation indicate three periods of metallogenesis, i. e. , volcano-sedimentation, magmatic-hydrothermal activity and regional metamorphism. The majority of the Fe-Mn metallogenic activity occurred during the volcano-sedimentation period. The homogenization temperatures of the liquid inclusions in quartz of the volcano-sedimentation period are concentrated between 170℃ and 300℃, with a peak temperature of 190℃, the salinities range from 3.23 % to 22.71 % , and the densities range from 0.62 to 1.09 g/cm3. The vapor and liquid composition of fluid inclusions in this period show that the ore-forming fluid was rich in Na+ , Cl and H2O, indicating that the ore-forming fluid was of moderate-low temperature, moderate-low salinity and

  2. Subsurface plumbing and fluid expulsion from sedimentary basins: evidence from the sedimentary record offshore West Africa (Invited)

    Science.gov (United States)

    Huuse, M.

    2010-12-01

    Many petroliferous basins around the world show evidence for fluid expulsion and seepage on the land surface or seafloor. However, not all fluid expulsion features are evidence of a working hydrocarbon systems and one needs to carefully evaluate fluid expulsion features and their associated geology and in particular their plumbing systems before inferring the nature of the expelled fluids. Geochemical fingerprinting of the migrating fluids may be sampled directly or via carbonate cements secreted in association with focus fluid conduits and may help determine the nature of the expelled fluids including their stratigraphic origin. When such evidence is unavailable, one may have to rely on remote sensing, including 3D seismic characterization in order to assess the nature of expelled fluids and links with hydrocarbon migration and/or ‘normal’ diagenetic fluid expulsion. This paper presents 3D seismic case studies of pockmarks, fluid flow pipes and polygonal fault systems which show evidence of both deep and shallow sources of expelled fluids and discuss the different controls on their occurrence and significance. Importantly, there is evidence of both conducting and sealing behaviours of polygonal fault sytems. Bottom-Simulating Reflections from interfaces between free gas and overlying gas hydrate occur in a variety of manifestations and may be linked with both deep and shallow sources of methane. Their depth of occurrence relative to seafloor depth may be used to infer local geothermal gradients and it is shown that underlying salt causes BSRs to shallow, indicative of a doubling of the geothermal gradient above salt structures compared to the adjacent salt mini basins. It is further suggested that salt structures on the middle slope serve a dual purpose as trap and leak-forming features, with traps focused on the down-dip side of overhanging diapirs and leaks located on the updip side and flanks. Associated leakage phenomena include gas and gas hydrate

  3. Mixing from below in hydrothermal ore deposits

    Science.gov (United States)

    Bons, Paul D.; Gomez-Rivas, Enrique; Markl, Gregor; Walter, Bejamin

    2014-05-01

    Unconformity-related hydrothermal ore deposits typically show indications of mixing of two end-member fluids: (a) hot, deep, rock-buffered basement brines and (b) colder fluids derived from the surface or overlying sediments. The hydromechanics of bringing these fluids together from above and below remain unclear. Classical percolative Darcy-flow models are inconsistent with (1) fluid overpressure indicated by fracturing and brecciation, (2) fast fluid flow indicated by thermal disequilibrium, and (3) strong fluid composition variations on the mm-scale, indicated by fluid inclusion analyses (Bons et al. 2012; Fusswinkel et al. 2013). We propose that fluids first descend, sucked down by desiccation reactions in exhumed basement. Oldest fluids reach greatest depths, where long residence times and elevated temperatures allow them the extensively equilibrate with their host rock, reach high salinity and scavenge metals, if present. Youngest fluids can only penetrate to shallower depths and can (partially) retain signatures from their origin, for example high Cl/Br ratios from the dissolution of evaporitic halite horizons. When fluids are released from all levels of the crustal column, these fluids mix during rapid ascent to form hydrothermal ore deposits. Mixing from below provides a viable hydromechanical mechanism to explain the common phenomenon of mixed shallow and deep fluids in hydrothermal ore deposits. Bons, P.D., Elburg, M.A., Gomez-Rivas, E. 2012. A review of the formation of tectonic veins and their microstructures. J. Struct. Geol. doi:10.1016/j.jsg.2012.07.005 Fusswinkel, T., Wagner, T., Wälle, M., Wenzel, T., Heinrich, C.A., Markl, M. 2013. Fluid mixing forms basement-hosted Pb-Zn deposits: Insight from metal and halogen geochemistry of individual fluid inclusions. Geology. doi:10.1130/G34092.1

  4. Origin and evolution of ore-forming fluids from Jiama copper polymetallic deposit in Tibet%西藏甲玛铜多金属矿床成矿流体来源及演化

    Institute of Scientific and Technical Information of China (English)

    周云; 张继超; 汪雄武; 唐菊兴; 秦志鹏; 彭惠娟; 李爱国; 杨科; 王华; 李炯

    2011-01-01

    A study of the homogenization temperature and characteristics of melt inclusions and fliud inclusions in the Jiama copper polymetallic deposit shows that the formation temperature of the porphyry body was 634~887℃,and the exsolution pressure of the fluids was 59.1 MPa.The temperature of five ore-forming stages was 170~540℃, the salinity concentration was 15%~50%, and the density was 0.9233~1.0805 g/cm3.The oreforming fluids were mainly of the NaCl-H2O system.The early ore pressure was higher than 31.8 MPa, and the early mineralization occurred below 1.1778 km.The ratios and illustration diagrams of ion compositions and gas compositions and the analyses of oxygen and hydrogen isotopes indicate that the ore-forming fluids of the Jiama copper polymetallic deposit were derived from magma, with the mixing of precipitated water in the late period.The formation and evolution of the ore-forming fluids experienced exsolution of magma, phase separation of supercritical fluid, decompression and boiling, the filling or metasomatism between magmatic hydrothermalvolatile fluids and carbonate wall rocks.The metallogenic elements selectively entered the volatile and were transported.The decompression, boiling and mixing resulted in the eventual precipitation of metallogenic elements.The ore deposit is genetically of magmatic-hydrothermal mineralization in the unified porphyry-skam-epithermal ore-forming system.%对斑岩、矽卡岩及角岩矿物中石英的熔融包裹体和流体包裹体进行测温,得到甲玛铜多金属矿床斑岩体形成温度为634~887℃,斑岩体中流体开始出溶的压力为59.1 MPa.从岩浆阶段、岩浆-热液阶段、矽卡岩阶段、矽卡岩退变质阶段到石英-硫化物阶段,温度范围为170~540℃,盐度集中在15%~50%范围内,密度为0.9233~1.0805 g/cm3,成矿流体主要为NaCl-H2O体系.早期最低成矿压力为31.8MPa,最浅成矿深度为1.1778 km.通过流体包裹体的离子成分、气相成

  5. Geology and geochemistry of the Macheng Algoma-type banded iron-formation, North China Craton: Constraints on mineralization events and genesis of high-grade iron ores

    Science.gov (United States)

    Wu, Huaying; Niu, Xianglong; Zhang, Lianchang; Pirajno, Franco; Luo, Huabao; Qin, Feng; Cui, Minli; Wang, Changle; Qi, Min

    2015-12-01

    The Macheng iron deposit is located in the eastern Hebei province of the North China Craton (NCC). It is hosted in Neoarchean metamorphic rocks of Baimiaozi formation in the Dantazi Group, consisting of biotite-leptynite, plagioclase-gneiss, plagioclase-amphibolite, migmatite, migmatitic granite and quartz schist. Geochemical analyses of the host biotite leptynite and plagioclase amphibolites show that their protoliths are both volcanics, inferred to be trachytic basalt and basaltic andesite, respectively. Based on the geochemical signature of the host rocks, together with geology of the iron deposit, it is inferred that the Macheng BIF is an Algoma-type iron exhalative formation, formed in an arc-related basin in the Neoarchean. Post-Archean Australian Shale (PAAS)-normalized rare earth elements (REEs) plus yttrium (Y) concentrations of different BIF ores with gneissic, striated and banded structure in the Macheng deposit, show similar patterns with depletions in light rare earth elements (LREEs) and middle rare earth elements (MREEs) relative to heavy rare earth elements (HREEs) and with apparently positive La, Y and Eu anomalies. Y/Ho ratios of the gneissic, striated and banded BIF ores vary from 37 to 56. These geochemical features of the BIF ores reveal their affinity with the sea water and the presence of a high-temperature hydrothermal component, indicating that both the seawater and high temperature hydrothermal fluids derived from alteration of oceanic basalts and komatiites may contribute to formation of the Macheng BIF. Geological, mineralogical and geochemical studies of the Macheng deposit recognized two kinds of high-grade iron ores. One is massive oxidized high-grade ore (Fe2O3T = 74.37-86.20 wt.%), mainly consisting of hematite with some magnetite, which shows geochemical characteristics of the gneissic, striated and banded BIF ores. The other type is magnetite high-grade ore, also massive and consisting of magnetite, with distinct characteristics

  6. Composition and source of salinity of ore-bearing fluids in Cu-Au systems of the Carajás Mineral Province, Brazil

    Science.gov (United States)

    Xavier, Roberto; Rusk, Brian; Emsbo, Poul; Monteiro, Lena

    2009-01-01

    The composition and Cl/Br – NaCl ratios of highly saline aqueous inclusions from large tonnage (> 100 t) IOCG deposits (Sossego, Alvo 118, and Igarapé Bahia) and a Paleoproterozoic intrusion-related Cu-Au-(Mo-W-Bi-Sn) deposit (Breves; < 50 Mt)) in the Carajás Mineral Province have been analysed by LA-ICP-MS and ion chromatography. In both Cu-Au systems, brine inclusions are Ca-dominated (5 to 10 times more than in porphyry Cu-Au fluids), and contain percent level concentrations of Na and K. IOCG inclusion fluids, however, contain higher Sr, Ba, Pb, and Zn concentrations, but significantly less Bi, than the intrusion-related Breves inclusion fluids. Cu is consistently below detection limits in brine inclusions from the IOCG and intrusion-related systems and Fe was not detected in the latter. Cl/Br and Na/Cl ratios of the IOCG inclusion fluids range from entirely evaporative brines (bittern fluids; e.g. Igarapé Bahia and Alvo 118) to values that indicate mixing with magma-derived brines. Cl/Br and Na/Cl ratios of the Breves inclusion fluids strongly suggest the involvement of magmatic brines, but that possibly also incorporated bittern fluids. Collectively, these data demonstrate that residual evaporative and magmatic brines were important components of the fluid regime involved in the formation of Cu-Au systems in the Carajás Mineral Province.

  7. The physical hydrogeology of ore deposits

    Science.gov (United States)

    Ingebritsen, Steven E.; Appold, M.S.

    2012-01-01

    Hydrothermal ore deposits represent a convergence of fluid flow, thermal energy, and solute flux that is hydrogeologically unusual. From the hydrogeologic perspective, hydrothermal ore deposition represents a complex coupled-flow problem—sufficiently complex that physically rigorous description of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC modeling) continues to challenge our computational ability. Though research into these coupled behaviors has found only a limited subset to be quantitatively tractable, it has yielded valuable insights into the workings of hydrothermal systems in a wide range of geologic environments including sedimentary, metamorphic, and magmatic. Examples of these insights include the quantification of likely driving mechanisms, rates and paths of fluid flow, ore-mineral precipitation mechanisms, longevity of hydrothermal systems, mechanisms by which hydrothermal fluids acquire their temperature and composition, and the controlling influence of permeability and other rock properties on hydrothermal fluid behavior. In this communication we review some of the fundamental theory needed to characterize the physical hydrogeology of hydrothermal systems and discuss how this theory has been applied in studies of Mississippi Valley-type, tabular uranium, porphyry, epithermal, and mid-ocean ridge ore-forming systems. A key limitation in the computational state-of-the-art is the inability to describe fluid flow and transport fully in the many ore systems that show evidence of repeated shear or tensional failure with associated dynamic variations in permeability. However, we discuss global-scale compilations that suggest some numerical constraints on both mean and dynamically enhanced crustal permeability. Principles of physical hydrogeology can be powerful tools for investigating hydrothermal ore formation and are becoming increasingly accessible with ongoing advances in modeling software.

  8. Crustal fluid and ash alteration impacts on the biosphere of Shikoku Basin sediments, Nankai Trough, Japan.

    Science.gov (United States)

    Torres, M E; Cox, T; Hong, W-L; McManus, J; Sample, J C; Destrigneville, C; Gan, H M; Gan, H Y; Moreau, J W

    2015-11-01

    We present data from sediment cores collected from IODP Site C0012 in the Shikoku Basin. Our site lies at the Nankai Trough, just prior to subduction of the 19 Ma Philippine Sea plate. Our data indicate that the sedimentary package is undergoing multiple routes of electron transport and that these differing pathways for oxidant supply generate a complex array of metabolic routes and microbial communities involved in carbon cycling. Numerical simulations matched to pore water data document that Ca(2+) and Cl(1-) are largely supplied via diffusion from a high-salinity (44.5 psu) basement fluid, which supports the presence of halophile Archean communities within the deep sedimentary package that are not observed in shallow sediments. Sulfate supply from basement supports anaerobic oxidation of methane (AOM) at a rate of ~0.2 pmol cm(-3) day(-1) at ~400 mbsf. We also note the disappearance of δ-Proteobacteria at 434 mbsf, coincident with the maximum in methane concentration, and their reappearance at 463 mbsf, coinciding with the observed deeper increase in sulfate concentration toward the basement. We did not, however, find ANME representatives in any of the samples analyzed (from 340 to 463 mbsf). The lack of ANME may be due to an overshadowing effect from the more dominant archaeal phylotypes or may indicate involvement of unknown groups of archaea in AOM (i.e., unclassified Euryarchaeota). In addition to the supply of sulfate from a basement aquifer, the deep biosphere at this site is also influenced by an elevated supply of reactive iron (up to 143 μmol g(-1)) and manganese (up to 20 μmol g(-1)). The effect of these metal oxides on the sulfur cycle is inferred from an accompanying sulfur isotope fractionation much smaller than expected from traditional sulfate-reducing pathways. The detection of the manganese- and iron-reducer γ-Proteobacteria Alteromonas at 367 mbsf is consistent with these geochemical inferences.

  9. The Ancient Ore-forming Fluids Study of Neglasari Mine in West Java, Indonesia%印度尼西亚西爪哇内格拉萨金矿区古成矿流体研究

    Institute of Scientific and Technical Information of China (English)

    徐晓璐; 高建国; 张利军

    2012-01-01

    通过对比研究各种类型矿石的化学组分、矿物共生组合、围岩蚀变特征,以及包体测温数据,初步认为金在古成矿流体在中低温、低氧逸度、pH值接近中性的物理化学环境中,以硫氢络合物(Au(HS))的形式迁移.流体物理化学环境的骤变是引起矿质元素沉淀的内因;而诱发物理化学环境改变的主要外界因素是流体的沸腾作用和硫化作用.基于研究区的大地构造背景、区域成矿带及矿区地质特征,提出“本区矿床属于火山-次火山杂岩成矿体系,相应的热液系统为与火山-次火山杂岩有关的岩浆-大气降水热液系统”的假设,并利用该假设解释本区矿床的成因.%In terms of the chemical composition, symbiotic mineral complexes of various ores, the characteris tics of wall-rock alteration, and homogenization temperature data of fluid inclusions, it is preliminarily concluded that gold in ancient ore-forming fluids migrated as ( Au ( HS) 2 ) under the condition which is low temperature, hy-poxia fugacity and pH close to neutral. The sudden change of physical chemistry condition is the essential cause that leaded gold in hydrothermal fluids to precipitation. And the outer inducement factors that caused physical chemistry environment change are primary fluids boiling and sulfuration. Based on the tectonic setting , regional metallogenic belt and geological characteristics of the mining area, one hypothesis deposit in mining area a part of a volcano-subvolcano complex metallogenic system. And the corresponding hydrothermal system is volcanic-subvocan-ic magma-ground water hydrothermal system is committed. It is easy to interpreter the genesis of this deposit in this mining area with this hypothesis.

  10. Structural and fluid-density controls on the flow system in the Paleozoic arches and basins of the Midwest

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, N.; Bair, E.S. (Ohio State Univ., Columbus, OH (United States). Dept. of Geological Sciences)

    1992-01-01

    Although many conceptual, theoretical, and field studies document the effects of topographic driving forces and the effects of variations in hydraulic conductivity on regional flow patterns, few studies document the effects of fluid-density-related driving forces on regional flow patterns. These few studies indicate that variations in the density of formation fluids in large sedimentary basins are common and can have a pronounced effect on the interpretation of flow directions and flow velocities. The authors goal is to develop an understanding of the influence of fluid-density variations on regional groundwater flow patterns in the Cambrian Mt. Simon Sandstone in the midwestern United States. This was accomplished using data contained in various geologic and hydrologic reports, results of drill-stem tests and core analyses, and information in petitions submitted by waste-injection operators as part of the federal LANDBAN program. These data were incorporated into a regional, three-dimensional, steady-state, finite-difference flow model used to simulate flow of variable-density fluids in the Mt. Simon Sandstone and in 10 overlying hydrostratigraphic units. The model covers an area of approximately 275,000 square miles, including all or parts of 8 states. Simulations were performed using equivalent-freshwater heads and using variable-fluid densities in a 12-layer model representing the entire stratigraphic sequence from the basal Cambrian Sandstone through the Pennsylvanian System and Pleistocene deposits. The results indicate that structural features such as the Cincinnati Arch and surrounding basins control the locations of ground-water divides and flow velocities. In areas of high fluid densities, flow directions and velocities show significant differences compared with flow directions and velocities based on freshwater heads.

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

    Science.gov (United States)

    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.

  12. Oil shales, evaporites and ore deposits

    Science.gov (United States)

    Eugster, Hans P.

    1985-03-01

    elevated temperatures and with carbonates as principal host rocks. The Pine Point deposits are cited for their close association with evaporites. Alkaline, metal-rich brines are postulated for the HYC deposit of McArthur River, Australia. Such brines are known from the Green River Formation and deposits formed from such brines constitute the GRT class. They can be recognized by the presence of Magadi-type cherts and zeolite-analcime-K-spar tuffs. The Cu-Co ore bodies of Outokumpu, Finland, might also belong to this type. A new classification of sedimentary ore deposits is proposed, based on their geochemical environment. KST and MVT are formed from acid ore fluids, while GRT and CT (Creede type) are derived from basic ore fluids. pH of the fluids is best evaluated not from the ores themselves, but from their effect on the host-rocks.

  13. Tectonomagmatic Metallogenic System of Dexing Ore Field, Jiangxi, China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    13 ore deposits and a large number of ore occurrences cluster in Dexing ore field which is 20 km long and 12 km wide. The tectonic evolution, magmatism, as well as the metallogeny are controlled by the Northeast Jiangxi deep-seated fracture belt (NJDFB). The source is believed to have been derived from the Meso-Neoproterozoic marine volcanism. The magmatic activity of Mesozoic I-type granite could have provided the metal elements, thermal fluid, heat, and the space for ore-forming processes. A unified geological model is proposed, which combines the tectonism, magmatism and metallogeny as the basic control of the giant metal mineralizations.

  14. Fluid flow in the northern Broad Fourteens Basin during Late Cretaceous inversion

    NARCIS (Netherlands)

    Oude Essink, Gualbert

    2003-01-01

    A basin-scale hydrogeological study of the inverted northern Broad Fourteens Basin, Netherlands offshore, has resulted in a reconstruction of geological evolution, an estimate of Late Cretaceous topography and model scenarios of syn-inversion meteoric water infiltration. This study was performed in

  15. 甘肃拾金坡金矿床成因:来自40Ar/39Ar定年、成矿流体及H-O-S同位素证据%Ore Genesis of the Shijinpo Gold Deposit in Gansu Province, NW China:40Ar/39Ar Dating, Ore-Forming Fluid and H-O-S Isotopes Constrains

    Institute of Scientific and Technical Information of China (English)

    朱江; 吕新彪; 莫亚龙; 曹晓峰; 陈超

    2013-01-01

    , variably coexisting with minor amounts of galena, sphalerite and chalcopyrite. Laser incremental heating 40Ar/39Ar analysis of hydrothermal sericite yields a plateau age of (364. 6 ± 3) Ma (2σ) , which suggests that the gold mineralization took place in the late Devonian period. The comprehensive fluid inclusion study shows that there are three major types of fluid inclusions in the early stage: liquid-rich, gas-rich aqueous and CO2-bearing fluid inclusions, with intermediate homogenization temperature (280 - 325℃) , and low salinity (7. 86%- 9. 21% NaCl eqv). The fluid boiling is evidenced by the co-existence of three types of fluid inclusions with similar homogenization temperatures. There is only liquid-rich aqueous fluid inclusions in the late stage, with hqmogenization temperatures and salinities varying from 160℃ to 230℃ , 9. 47% to 11. 10%Nacl equivalent. Fluid pressures declined from ca. 113 MPa to ca. 11 MPa through the early stage to the late stage, and the ore-forming fluids are assumed to undergo boiling in a transitional setting (from compression to extension). Oxygen and hydrogen isotopic contents in the ore-forming fluid range from 1. 39%o to 3. 39%o and - 71%o to -99%o, respectively, suggesting that the ore-forming fluid was mainly derived from the metamorphic water, and mixed by the meteoric water in the late stage. The measured δ34 S values in sulfide minerals range from 4. 44%o to 11. 33%o. Both the Precambrian metamorphic rock and granitic wall-rock might be the sulfur sources. Based on the paper and the regional geologic data, we conclude that the Shijinpo gold deposit belongs to the orogenic-type gold deposit.

  16. Source of ore-forming material for the Huangtuliang gold deposit, Hebei Province and ore prospecting in the deep periphery

    Institute of Scientific and Technical Information of China (English)

    NIU Shuyin; SUN Aiqun; WANG Baode; HAN Yuchou; WEI Minghui; ZHANG Hai; ZHANG Ge; SHI Ping; WANG Wenxing

    2008-01-01

    The Huangtuliang gold deposit is characterized by its wide and large ore belt, stable extension and closely spaced orebodies. Unfortunately, no orebody was found by deep drilling. As a result, ore prospecting in this region was once put into dilemma. Detailed analysis of ore-forming and ore-controlling structures in the mining district by the authors has revealed that the ore-forming and ore-controlling structure in this mining district is a steeply dipping (85°-110°/∠70°-85° N-NNE), spade-shaped ductile shear zone, and the ore-controlling structures are a series of nearly erected second-ordered faults which are developed in the upper part of the ductile shear zone, intersecting with the ductile shear zone. Deep cutting of the ductile shear zone made it possible the ascending of ore fluids from the mantle plume at depth and these ore fluids would migrate upwards along the ductile shear zone under certain temperature and pressure conditions. Along their ascending path, the ore fluids would extract ore-forming elements from the country rocks and the extracted ore-forming elements would be deposited as ores in the hanging-wall second-ordered faults. The reason why no orebody was found in early prospecting at depth is that northward-dipping drilling in the southern part of the shear zone extended so deeply as to be beneath the shear zone. Only shallow-level orebodies could be found by southward-dipping drilling practice in the northern part of the shear zone.The location where deep-seated orebodies occurred shifted northwards and the orebodies occurred at greater depth.Therefore, it is natural that no orebody could be found when drill core passed through the shear zone. After the ore-forming and ore-controlling structures were well understood, the focus of ore prospecting was placed on the deep-level, northward-penetrating veins. In this way a number of new blind orebodies of great thickness have been found. On the basis of research development in the mining

  17. Sequential extraction and compositional analysis of oil-bearing fluid inclusions in reservoir rocks from Kuche Depression, Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The free oils, adsorbed oils and oil-bearing fluid inclusions have been extracted separately and analyzed by GC and GC-MS in reservoir rock samples collected from the Kuche Depression. The results demonstrate that the molecular compositions of oil-bearing fluid inclusions are significantly different from those of the free oils (the current oils). Compared with the current oil, the oil-bearing fluid inclusions are characterized by relatively high values of parameters Pr/nC17and Ph/nC18, low values of Pr/Ph, hopanes/steranes, C30-diahopane/C30-hopane and Ts/Tm, low content of C29Ts terpane and high maturities as indicated by C29 steranes 20S/(20R+20S). In addition, the oil-bearing fluid inclusions correlate very well with the oils in northern and central Tarim Basin, which were derived from Cambrian-Ordovician marine source rocks. The adsorbedoils appear to be an intermediate type between free oils and oil-bearing fluid inclusions. The above analytical data indicate that there are at least two oil-charging episodes for these reservoir rock samples. The early charging oils were derived from Cambrian-Ordovician marine source rocks, and the later charging oils, from Triassic-Jurassic terrestrial source rocks. The primary marine oils were overwhelmingly diluted by the following terrestrial oils.

  18. Modeling fluid flow and heat transfer at Basin and Range faults: preliminary results for Leach hot springs, Nevada

    Science.gov (United States)

    López, Dina L.; Smith, Leslie; Storey, Michael L.

    1994-01-01

    The hydrothermal systems of the Basin and Range Province are often located at or near major range bounding normal faults. The flow of fluid and energy at these faults is affected by the advective transfer of heat and fluid from an to the adjacent mountain ranges and valleys, This paper addresses the effect of the exchange of fluid and energy between the country rock, the valley fill sediments, and the fault zone, on the fluid and heat flow regimes at the fault plane. For comparative purposes, the conditions simulated are patterned on Leach Hot Springs in southern Grass Valley, Nevada. Our simulations indicated that convection can exist at the fault plane even when the fault is exchanging significant heat and fluid with the surrounding country rock and valley fill sediments. The temperature at the base of the fault decreased with increasing permeability of the country rock. Higher groundwater discharge from the fault and lower temperatures at the base of the fault are favored by high country rock permabilities and fault transmissivities. Preliminary results suggest that basal temperatures and flow rates for Leach Hot Springs can not be simulated with a fault 3 km deep and an average regional heat flow of 150 mW/m2 because the basal temperature and mass discharge rates are too low. A fault permeable to greater depths or a higher regional heat flow may be indicated for these springs.

  19. Ores and Climate Change - Primary Shareholders

    Science.gov (United States)

    Stein, Holly J.; Hannah, Judith L.

    2015-04-01

    Many in the economic geology community concern themselves with details of ore formation at the deposit scale, whether tallying fluid inclusion data to get at changes in ore-forming fluids or defining structures that aid and abet mineralization. These compilations are generally aimed at interpretation of events at the site of ore formation, with the goal being assignment of the deposit to a sanctioned ore deposit model. While providing useful data, this approach is incomplete and does not, by itself, serve present-day requirements for true interdisciplinary science. The ore-forming environment is one of chaos and disequilibrium at nearly all scales (Stein, 2014). Chaos and complexity are documented by variably altered rocks, veins or disseminated mineralization with multi-generational fluid histories, erratic and unusual textures in host rocks, and the bitumen or other hydrocarbon products entwined within many ore deposits. This should give pause to our drive for more data as a means to find "the answer". The answer lies in the kind of data collected and more importantly, in the way we interpret those data. Rather than constructing an ever-increasing catalog of descriptive mutations on sanctioned ore deposit models (e.g., IOGC or Iron-Oxide Copper Gold deposits), the way forward is to link source and transport of metals, sulfur, and organic material with regional and ultimately whole Earth chemical evolution. Important experimental work provides chemical constraints in controlled and behaved environments. To these data, we add imagination and interpretation, always tying back to field observations. In this paper, several key points are made by way of ore deposit examples: (1) many IOCG deposits are outcomes of profound changes in the chemistry of the Earth's surface, in the interplay of the atmosphere, hydrosphere, biosphere, and lithosphere; (2) the redox history of Fe in deep earth may be ultimately expressed in the ore-forming sequence; and (3) the formation of

  20. The Vein-type Zn-(Pb, Cu, As, Hg) mineralization at Fedj Hassene ore field, North-Western Tunisia: Mineralogy, Trace Elements, Sulfur Isotopes and Fluid Inclusions; Le champ filonien a Zn-(Pb, Cu, As, Hg) du district minier de Fedj Hassene (Nord Ouest de la Tunisie): Mineralogie, Elements en traces, Isotopes du Soufre et Inclusions Fluides

    Energy Technology Data Exchange (ETDEWEB)

    Bejaouil, J.; Bouhlel, S.; Barca, D.; Braham, A.

    2011-07-01

    The Fedj Hassene district is localized at the edge of the Tuniso-Algerian border 10 km of Ghardimaou area. It consists of a Zn-Pb vein type with minor amounts of Cu-As-Hg. The total Zn reserves are about 370.000t. The mineralization occurs within sub parallel fractures to the Ain El Kohla ESE-WNW fault. Host rocks consist of limestones and marly limestones of the Middle Turonian. In the principal lode of Fedj Hassene, the mineralization occurs as vein filling of massive and brecciated brown sphalerite and minor galena ore with gangue. Other trace minerals are pyrite, chalcopyrite, orpiment, realgar, smithsonite and cerussite. LA-ICP-MS analyses in sphalerites show mean contents of 0,84 wt% Fe, 0,14 wt% Cd and 0,02 wt% Mn Ore. Fluid inclusions study in calcite and sphalerite reveals one mineralizing fluid characterized by an average salinity 23% wt NaCl with decreasing homogenisation temperature. In fact the temperature shows decrease from sphalerite to calcite. The fluid density that corresponds to trapping pressure ranges between 1.00 g/cm{sup 3} and 1.11 g/cm{sup 3} and pressure close to 200 bars. Micro thermometric data in fluid inclusion hosted by gangue mineral presented by calcite show an average temperature of formation around 194 degree centigrade. These inclusions homogenized to the liquid phase between 156 degree centigrade and 210 degree centigrade and salinities values ranging from 22 to 28 wt% NaCl and an average around 23% wt NaCl. The {delta}{sup 3}4S (VCDT) values of sphalerite are in the range of + 4,6% to 6,4% (average=5,6%). Thermochemical reduction of Triassic sulfate by reaction with hydro-carbons is the most probable source for the heavy and the narrow range of the d{delta}{sup 3}4S values. Mineralogical, geochemical of trace elements, fluid inclusions and sulfur isotopes studies allow to include the vein-type ore field of Fedj Hassene in the polymetallic (Pb-Zn-As-Hg) vein mineralization of the nappe zone in northern Tunisia and north eastern

  1. Metallization of oxide-ore-containing wastes with the use of brown coal semicoke from Berezovsky deposit of the Kansk- Achinsk Basin

    Science.gov (United States)

    Anikin, A. E.; Galevsky, G. V.; Nozdrin, E. V.; Rudneva, V. V.; Galevsky, S. G.

    2016-09-01

    The research of the metallization process of the roll scale and sludge after gas treatment in the BOF production with the use of brown coal semicoke mined in Berezovsky field of the Kansk-Achinsk Basin was carried out. A flow diagram of “cold” briquetting using a water-soluble binder was offered. The reduction of iron from its oxide Fe2O3 with brown coal semicoke in the laboratory electric-tube furnace in the argon atmosphere was studied. The mathematical models of dependence of the metallization degree on variable factors were developed. The optimal values of technological factors and essential characteristics of the obtained metallized products were revealed.

  2. Isotopic Characteristics of Mesozoic Au-Ag Polymetallic Ore Deposits in Northern Hebei and Their Ore-Forming Materials Source

    Institute of Scientific and Technical Information of China (English)

    王宝德; 牛树银; 孙爱群; 李红阳

    2003-01-01

    It has long been a controversy about the source of ore-forming materials of Au-Agpolymetallic deposits both in metallogenic theory and in ore-searching practice. In terms of alarge wealth of the isotopic statistics data from Indosinian-Yanshanian endogenic ore deposits innorthern Hebei (generally referring to the areas along the northern part of Taihang Mountainsand northern Hebei, the same below) , it is considered that the ore-forming materials came fromthe deep interior of the Earth, which had migrated through plumes to the Earth surface while ex-perienced multi-stage evolution and then emplaced progressively in favorable structural loci toform ores. Their isotope data show that 559 sulfur isotopic data from 40 ore deposits are, for themost part, within the range of - 5‰ - 5‰, with a high degree of homogenization, indicatingthat the sulfur is derived mainly from magma; 200 lead isotope data from 37 ore deposits indi-cate that the ore-forming materials are principally of mantle source though some crust-source ma-terial was involved; 96 oxygen, hydrogen and carbon isotope data from 34 ore deposits illustratethat the ore-forming fluids are dominated by magmatic water while other sources of water wouldbe involved. It may therefore be seen that the formation of endogenic deposits has nothing to dowith the strata.

  3. Diagenesis and Fluid Flow History in Sandstones of the Upper Permian Black Jack Formation, Gunnedah Basin, Eastern Australia

    Institute of Scientific and Technical Information of China (English)

    BAI Guoping; John B. KEENE

    2007-01-01

    The fluid flow history during diagenesis of sandstones in the Upper Permian Black Jack Formation of the Gunnedah Basin has been investigated through integrated petrographic observations, fluid inclusion investigations and stable isotope analyses. The early precipitation of mixed-layer illite/smectite, siderite, calcite, ankerite and kaolin proceeded at the presence of Late Permian connate meteoric waters at temperatures of up to 60℃. These evolved connate pore waters were also parental to quartz, which formed at temperatures of up to 87℃. The phase of maximum burial was characterized by development of filamentous illite and late calcite at temperatures of up to ~90℃. Subsequent uplifting and cooling led to deep meteoric influx from surface, which in turn resulted in dissolution of labile grains and carbonate cements, and formation of second generation of kaolin. Dawsonite was the last diagenetic mineral precipitated and its formation is genetically related to deep-seated mamagtic sourced CO2.

  4. Methane-rich fluid inclusions and their hosting volcanic reservoir rocks of the Songliao Basin, NE China

    Institute of Scientific and Technical Information of China (English)

    WANG Pu-Jun; HOU Qi-jun; CHENG Ri-hui; LI Quan-lin; GUO Zhen-hua; HUANG Yu-long

    2004-01-01

    Methane-rich fluids were recognized to be hosted in the reservoir volcanic rocks as primary inclusions.Samples were collected from core-drillings of volcanic gas reservoirs with reversed δ12C of alkane in the Xujiaweizi depression of the Songliao Basin. The volcanic rocks are rhyolite dominant being enriched in the more incompatible elements like Cs, Rb, Ba, Th, U and Th with relative high LREE, depleted HREE and negative anomalies of Ti and Nb,suggesting a melt involving both in mantle source and crustal assimilation. Primary fluids hosted in the volcanic rocks should have the same provenance with the magma. The authors concluded that the enclosed CH4 in the volcanics are mantle/magma-derived alkane and the reversed δ13C of alkane in the corresponding gas reservoirs is partly resulted from mixture between biogenic and abiogenic gases.

  5. Coincidence or not? Interconnected gas/fluid migration and ocean-atmosphere oscillations in the Levant Basin

    Science.gov (United States)

    Lazar, Michael; Lang, Guy; Schattner, Uri

    2016-08-01

    A growing number of studies on shallow marine gas/fluid systems from across the globe indicate their abundance throughout geological epochs. However, these episodic events have not been fully integrated into the fundamental concepts of continental margin development, which are thought to be dictated by three elements: tectonics, sedimentation and eustasy. The current study focuses on the passive sector of the Levant Basin on the eastern Mediterranean continental margin where these elements are well constrained, in order to isolate the contribution of gas/fluid systems. Single-channel, multichannel and 3D seismic reflection data are interpreted in terms of variance, chaos, envelope and sweetness attributes. Correlation with the Romi-1 borehole and sequence boundaries constrains interpretation of seismic stratigraphy. Results show a variety of fluid- or gas-related features such as seafloor and subsurface pockmarks, volumes of acoustic blanking, bright spots, conic pinnacle mounds, gas chimneys and high sweetness zones that represent possible secondary reservoirs. It is suggested that gas/fluid migrate upwards along lithological conduits such as falling-stage systems tracts and sequence boundaries during both highstands and lowstands. In all, 13 mid-late Pleistocene sequence boundaries are accompanied by independent evidence of 13 eustatic sea-level drops. Whether this connection is coincidental or not requires further research. These findings fill gaps between previously reported sporadic appearances throughout the Levant Basin and margin and throughout geological time from the Messinian until the present day, and create a unified framework for understanding the system as a whole. Repetitive appearance of these features suggests that their role in the morphodynamics of continental margins is more important than previously thought and thus may constitute one of the key elements of continental margin development.

  6. Inclusiones fluidas e isotopos estables en la ganga de los yacimientos de manganeso del norte de la provincia de Córdoba Fluid inclusions and stable isotopes in non-ore minerals of the manganese ore deposits in the north of the Córdoba province

    Directory of Open Access Journals (Sweden)

    P.R. Leal

    2002-09-01

    Full Text Available En este trabajo se analizan las características físico-químicas asociadas a la precipitación de la ganga de yacimientos epitermales de manganeso. Estos minerales fueron formados principalmente durante la etapa póstuma del sistema, el cual es posible dividir espacialmente en tres sectores en función del mineral más abundante. En esta oportunidad se estudia el sector austral donde el mineral más común es la calcita. El análisis microtermométrico de las inclusiones fluidas sobre muestras de calcita, baritina y fluorita, hizo posible obtener salinidades del fluido de 2,7 y 4% eq. en peso NaCl y temperaturas inferiores a 100°C. Los estudios de isótopos de 13C, 18O y 34S en calcita y baritina permitieron determinar la fuente meteórica de los fluidos asociados a su precipitación. Al mismo tiempo los valores de d13C en calcita se consideran el resultado de un fluido en equilibrio con CO2 atmosférico y cantidades menores de carbono producto de la disolución de compuestos orgánicos. Por otro lado, los valores de d34S de la baritina pueden ser explicados por un fluido con H2S que resulta de la disolución de sulfuros de las rocas de caja. Finalmente, se postula la presencia de dos fluidos. Un fluido ascendente fue el responsable de la precipitación de la baritina en la zona donde el H2S se oxida a SO4=; al mismo tiempo, éste pudo también formar fluorita y variedades de sílice conforme su temperatura desciende. La existencia de un fluido descendente permite explicar la generación de calcita por calentamiento del mismo.In this paper the non-ore minerals of the southern sector of this deposit are studied. Microthermometric analysis on calcite, barite and fluorite show fluid salinities of 2.7 and 4% wt eq. NaCl, and temperatures below 100°C. Isotopes of 13C, 18O and 34S allow to determine a meteoric source for the fluids associated to their precipitation. The d13C values obtained in calcite are considered the result of a fluid in

  7. Variability in the microbial communities and hydrothermal fluid chemistry at the newly discovered Mariner hydrothermal field, southern Lau Basin

    Science.gov (United States)

    Takai, Ken; Nunoura, Takuro; Ishibashi, Jun-Ichiro; Lupton, John; Suzuki, Ryohei; Hamasaki, Hiroshi; Ueno, Yuichiro; Kawagucci, Shinsuke; Gamo, Toshitaka; Suzuki, Yohey; Hirayama, Hisako; Horikoshi, Koki

    2008-06-01

    A newly discovered hydrothermal field called the Mariner field on the Valu Fa Ridge in the southern Lau Basin was explored and characterized with geochemical and microbiological analyses. The hydrothermal fluid discharging from the most vigorous vent (Snow Chimney, maximum discharge temperature 365°C) was boiling at the seafloor at a depth of 1908 m, and two distinct end-member hydrothermal fluids were identified. The fluid chemistry of the typical Cl-enriched and Cl-depleted hydrothermal fluids was analyzed, as was the mineralogy of the host chimney structures. The variability in the fluid chemistry was potentially controlled by the subseafloor phase-separation (vapor loss process) and the microbial community activities. Microbial community structures in three chimney structures were investigated using culture-dependent and -independent techniques. The small subunit (SSU) rRNA gene clone analysis revealed that both bacterial and archaeal rRNA gene communities on the chimney surfaces differed among three chimneys. Cultivation analysis demonstrated significant variation in the culturability of various microbial components among the chimneys, particularly of thermophilic H2-oxidizing (and S-oxidizing) chemolithoautotrophs such as the genera Aquifex and Persephonella. The physical and chemical environments of chimney surface habitats are still unresolved and do not directly extrapolate the environments of possible subseafloor habitats. However, the variability in microbial community found in the chimneys also provides an insight into the different biogeochemical interactions potentially affected by the phase separation of the hydrothermal fluids in the subseafloor hydrothermal habitats. In addition, comparison with other deep-sea hydrothermal systems revealed that the Mariner field microbial communities have unusual characteristics.

  8. Natural gas generation model and its response in accumulated fluids in the Yinggehai basin

    Institute of Scientific and Technical Information of China (English)

    郝芳; 邹华耀; 黄保家

    2003-01-01

    The natural gases found in the Yinggehai basin have nitrogen gas content ranging from 3.5% to 35%, and carbon dioxide content ranging from 0.1% to 93%. The nitrogen and CO2 contents show a wide variation even in the same gas field. The natural gas generation and evolution model has been established based on the relationship among the contents of nitrogen, carbon dioxide and hydrocarbon gases in the discovered gas fields, and the results of simulation experiments. The thickness of the Tertiary and Quaternary in the Yinggehai basin is over 17 km, and gas generation stages from diagenesis (microbial methane) to metamorphism have been developed. Nitrogen in this basin is organic in origin, and has been generated mainly in the catagenetic stage, roughly synchronous with hydrocarbon gases. Carbon dioxide is mainly inorganic in origin, and has been generated from high-temperature decomposition of carbonates in the metamorphic stage. The Dongfang gas field shows strong inter-reservoir compositional heterogeneities, and different gas reservoirs have recorded the products of gas generation at different stages. It has been confirmed that the complexity in natural gas composition in the Yinggehai basin is the combined results of multi-stage natural gas generation and multi-stage gas injection and accumulation.

  9. Fluid Flow History in Lower Triassic Bulgo Sandstone, Central Sydney Basin, Australia

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The fluid flow history during diagenesis of the Lower Triassic Bulgo sandstone has been investigated through integrated analyses of petrography, stable isotope and fluid inclusion. Combined application of these techniques was intended to constrain the temperature, timing, chemistry and source of pore fluids during diagenetic cementation events in the Lower Triassic Bulgo sandstone. The dlagenesis proceeded in two different flow regimes: early dynamic fluid flow regime and late slow static fluid flow regime. The former was characterized by a slight increase of δ(18O) of pore waters form estimated -15 × 10-3 to -14 × 10-3 with the temperature increasing from ~ 10 ℃ to ~ 75 ℃. During early diagenesis, early clays and pore filling carbonates precipitated from the pore waters. The late slow flow/static fluid regime was characterized by a rapid 18O-enrichment process. δ(18O) of pore waters increased from -14× 10-3 to -5× 10-3 with the temperature increasing from 75 ℃ to 110 ℃. During the late diagenesis, kaolin (generation Ⅲ ), quartz and illite crystallized. Oil migrated to the sandstones of the Bulgo sandstone during quartz cementation.

  10. 云南毛坪铅锌(银、锗)矿床流体包裹体特征及成矿流体来源%Features of fluid inclusions and sources of ore-forming fluid in the Maoping carbonate-hosted Zn-Pb-( Ag-Ge) deposit, Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    韩润生; 邹海俊; 胡彬; 胡熠昭; 薛传东

    2007-01-01

    The Maoping Zn-Pb-(Ag-Ge) deposit is an important representative of the medium-to large-sized carbonate-hosted Zn-Pb-(Ag) deposits in northeast Yunnan, occurring in the Sichuan-Yunnan-Guizhou Zn-Pb Ore-forming Zone. The spatial distribution of ore bodies were controlled by the NE-extending interstratified fault belts and inverted Maomaoshan fold. Generally, fluid inclusions within the major gangue minerals, as ferro-calcite, calcite and dolomite are dominated by two kinds of small inclusions (3~15 μm) including pure-liquid and liquid. The inclusions exist in concentrated groups along the crystal planes of the gangue minerals. The ore-forming fluids belong to the Na+ -K+ -Ca2+ -Cl- -F - type, are characterized by temperatures of 180 ~ 218 ℃, medium salinity in 4. 1 wt% ~ 9.5wt% NaCl, and medium pressure at 406×105~570×105 Pa. The ratios of Na+/K+ (1.54~4.53 ) and Cl-/F- (0.72 ~ 156.33 ) in the fluid inclusions of gangue minerals are relatively high, while those of Na+/K+ (0. 32 ~ 8.36 ) and Cl-/F- (1.06 ~ 16.77) in the inclusions of barite are relatively low. The waters of fluid inclusions have δD values from -23‰ to -64‰. The δ18OV.SMOWvalues of the ore-forming fluids range from 0. 3‰ to 6.2‰ for galena, -9.0‰ to 3.4‰ for sphalerite, and -6.8‰ to -12.7‰ for pyrite. δ13CV-PDBvalues range from -1.1 to -3.7 for gangue minerals. These data better demonstrate that the ore-forming fluids were the compositing results of the magma water, metamorphic water and hosted water, and mainly derived from magmatic hot fluid and hosted formation water, in relation to the sedimentation, the metamorphism of the Kunyang Group in the basement and magmatic hydrothermalism. The deposit itself might have resulted from ascending cycles along metallogenic structures of ore-forming fluid, enriched in Pb, Zn and Ag. The deposit is related to carbonate-hosted Zn-Pb sulphides.%云南毛坪铅锌(银、锗)矿床是川滇黔成矿域滇东北地区以碳

  11. Fluids preserved in variably altered graphitic pelitic schists in the Dufferin Lake Zone, south-central Athabasca Basin, Canada: implications for graphite loss and uranium deposition

    Science.gov (United States)

    Pascal, Marjolaine; Boiron, Marie-Christine; Ansdell, Kevin; Annesley, Irvine R.; Kotzer, Tom; Jiricka, Dan; Cuney, Michel

    2016-06-01

    The Athabasca Basin (Canada) contains the highest grade unconformity-type uranium deposits in the world. Underlying the Athabasca Group sedimentary rocks of the Dufferin Lake Zone are variably graphitic, pelitic schists (VGPS), altered to chlorite and hematite (Red/Green Zone: RGZ). They were locally bleached near the unconformity during paleoweathering and/or later fluid interaction. Overall, graphite was lost from the RGZ and the bleached zone relative to the original VGPS. Fluid inclusions were examined in different generations of quartz veins, using microthermometry and Raman spectroscopy, to characterize and compare the different fluids that interacted with the RGZ and the VGPS. In the VGPS, CH4-, and N2-rich fluid inclusions, which homogenize into the vapor phase between -100 and -74 °C, and -152 and -125 °C, respectively, and CO2-rich fluid inclusions, homogenizing either into vapor or liquid between 20 and 28 °C, are present. Carbonic fluids could be the result of the breakdown of graphite to CH4 + CO2, whereas N2-rich fluid is interpreted to be the result of breakdown of feldspars/micas to NH4 ++N2. In the RGZ, the presence of fluid inclusions with low ice melting temperature (-38 to -16 °C) reflect the presence of CaCl2, and fluid inclusions with halite daughter minerals that dissolve between 190 and 240 °C indicate the presence of highly saline fluids. These fluids are interpreted to be derived from the Athabasca Basin. The circulation of carbonic fluids and brines occurred during two different events related to different P-T conditions of trapping. The carbonic fluids interacted with basement rocks during retrograde metamorphism of the basement rocks before deposition of the Athabasca Basin, whereas the brines circulated after the deposition of the Athabasca Basin. These latter fluids are similar to brines related to uranium mineralization at McArthur River and thus, in addition to possibly being related to graphite depletion in the RGZ, they could

  12. Thermodynamic Modeling of Fluid-Bearing Natural Gas Inclusions for Geothermometer and Geobarometer of Overpressured Environments in Qiongdongnan Basin, South China Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    It is a very difficult problem to directly determine fluid pressure during hydrocarbon migration and accumulation in sedimentary basins. pVt modeling of coupling hydrocarbon fluid inclusion of its coeval aqueous fluid inclusion provides a powerful tool for establishing the relationship of formation pressure evolution with time. Homogenization temperature of fluid inclusion can routinely be measured under microthermometric microscopy. Crushing technique has been employed to obtain the composition of fluid inclusions, and the commercial software VTFLINC easily and rapidly completes the construction of p-t phase diagram. The minimum trapping pressure of hydrocarbon fluid inclusion would be then determined in the p-t space. In this paper, three samples of YC21-1-1 and YC21-1-4 wells at YC21-1 structural closure, Qiongdongnan basin, South China Sea, were selected for the pVt modeling practice, and the formation pressure coefficient (equals to fluid pressure/hydrostatic pressure) changing trend with time has primarily been established. The modeling results also indicate that the reservoirs of Lingshui and Yacheng formations in YC21-1 structure are within a very high potential system and would have undergone a discharging of thermal fluids through top seal rupture, which depicts that there is a very high risk for natural gas exploration in this area.

  13. Three-dimensional simulation of pore scale fluid flow in granular ore media with realistic geometry%基于真实模型的矿岩散体三维孔隙流数值模拟

    Institute of Scientific and Technical Information of China (English)

    杨保华; 吴爱祥; 王春来; 牛文鑫; 刘金枝

    2012-01-01

    利用X光CT技术采集矿岩散体图像,结合数字图像处理技术和有限元技术构建了表征介质真实孔隙结构的三维物理模型,利用此模型进行颗粒间孔隙流的三维数值模拟,分析堆浸散体孔隙内溶液流速和压力分布规律,并计算出介质的水力传导系数.模拟结果表明溶液流动行为在很大程度上受到孔隙大小及拓扑结构的制约,介质内同时存在明显的优势流和浸出盲区,最高流速出现在具有高压降的细小孔隙处.根据模拟结果计算出的水力传导系数与室内实验测试结果具有相同数量级,说明了模型的有效性.实现了细观尺度与宏观尺度的结合,所构建的模型能应用于堆浸过程其它规律的计算机模拟.%The images of granular ore media were captured by X-ray CT scanner.Combined with digital image processing and finite element techniques,the three-dimensional geometrical model,which represents the realistic pore structure of the media,was constructed.With this model,three dimensional pore scale fluid flow among particles was simulated.Then the distributions of fluid flow velocity and pressure were analyzed and the hydraulic conductivity was calculated.The simulation results indicate the fluid flow behaviors are mainly dominated by the volume and topological structure of pore space.There exist obvious preferential flow and leaching blind zones simultaneously in the medium.The highest velocities generally occur in those narrow pores with high pressure drops.The hydraulic conductivity obtained by simulation is the same order of magnitude as the laboratory test result,which denotes the validity of the model.The pore-scale and macro-scale are combined and the established geometrical model can be used for the simulations of other phenomena during heap leaching process.

  14. Determination of paleo-pressure for a natural gas pool formation based on PVT characteristics of fluid inclusions in reservoir rocks--A case study of Upper-Paleozoic deep basin gas trap of the Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    MI Jingkui; XIAO Xianming; LIU Dehan; SHEN Jiagui

    2004-01-01

    It has been proved to be a difficult problem to determine directly trapping pressure of fluid inclusions. Recently, PVT simulation softwares have been applied to simulating the trapping pressure of petroleum inclusions in reservoir rocks, but the reported methods have many limitations in practice. In this paper, a method is suggested to calculating the trapping pressure and temperature of fluid inclusions by combining the isochore equations of a gas-bearing aqueous inclusion with its coeval petroleum inclusions. A case study was conducted by this method for fluid inclusions occurring in the Upper-Paleozoic Shanxi Formation reservoir sandstones from the Ordos Basin. The results show that the trapping pressure of these inclusions ranges from 21 to 32 MPa, which is 6-7 MPa higher than their minimum trapping pressure although the trapping temperature is only 2-3℃ higher than the homogenization temperature. The trapping pressure and temperature of the fluid inclusions decrease from southern area to northern area of the basin.The trapping pressure is obviously lower than the state water pressures when the inclusions formed. These data are consistent with the regional geological and geochemical conditions of the basin when the deep basin gas trap formed.

  15. MAGnetiC AnoMAly feAtureS of the MAbiAnShAn iron ore DepoSit in the northern pArt of the lu-ZonG volCAniC bASin AnD ore-proSpeCtinG proGnoSiS%庐枞火山岩盆地北部马鞭山铁矿床磁异常特征及找矿预测

    Institute of Scientific and Technical Information of China (English)

    尚世贵

    2014-01-01

    The Mabianshan iron ore deposit lies at northern fringe of the Lu-Zong volcanic basin and is hosted in the Dongmaanshan (T2d) iron-bearing and calcareous muddy siltstone. Aeromagnetic map shows that gradient zone is locally overlapped with anomaly, and the local anomaly is regular in form with its trend generally parallel to the zone. Ground magnetic and aeromagnetic features are well matched, without decomposed anomaly. Ground magnetic profile curve is continuous, complete, with pairs of negative and positive and gentle. Wavelet transformation well separates out mineralized anomaly. Local gentle magnetic anomalies on the west and north sides of the basin are important indicators for seeking this kind of iron ore deposit.%马鞭山铁矿处于庐枞火山岩盆地北部边缘,其赋矿层位为东马鞍山(T2d)含铁质、钙质泥质粉砂岩。航磁为梯度带上叠加局部异常、局部异常形态规则,其走向与梯度带大致平行;地磁与航磁对应较好,异常未分解;地磁异常剖面曲线连续完整且正负伴生、具低缓特征。小波变换较好地分离出了矿致异常。盆地西侧和北侧二条航磁梯度带上局部低缓磁异常系寻找该类铁矿的重要指示信息。

  16. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    ZHU RuKai; ZOU CaiNeng; ZHANG Nai; WANG XueSong; CHENG Rong; LIU LiuHong; ZHOU ChuanMin; SONG LiHong

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity.The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas.Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites)→ first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores→ dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→ intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation.Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth.In a long-term closed system, only feldspars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation.This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally.The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  17. Diagenetic fluids evolution and genetic mechanism of tight sandstone gas reservoirs in Upper Triassic Xujiahe Formation in Sichuan Basin, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity. The general physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas. Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites) →first quartz overgrowth→chlorite coatings→dissolution of feldspars and debris→chlorite linings→ second quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores)→dissolution→third quartz overgrowth (quartz filled in intergranular and intragranular solution pores)→intergrowth (ferro) calcites→dolomites→ferro (calcites) dolomites→later dissolution→veins of quartz and calcites formation. Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth. In a long-term closed system, only feld-spars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation. This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally. The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs.

  18. Diagenesis and fluid flow in the San Juan Basin, New Mexico - regional zonation in the mineralogy and stable isotope composition of clay minerals in sandstone.

    Science.gov (United States)

    Whitney, G.; Northrop, H.R.

    1987-01-01

    The Westwater Canyon Member of the Upper Jurassic Morrison Formation is a relatively homogeneous, hydrologically continuous 100-m-thick sequence of massive fluvial sandstone, bounded above and below by relatively heterogeneous, hydrologically discontinuous units and has served as a primary conduit for fluids within this stratigraphic interval. Patterns of mineral-fluid reactions suggest a basinwide hydrologic regime in which warm, evolved fluids migrated up-dip from the center of the basin under the influence of a regional hydraulic head. -from Authors

  19. Ore-Forming Fluid Geochemical Characteristics and Genesis of Pb-Zn Deposit in Hongling,Inner Mongolia%内蒙古红岭铅锌矿床成矿流体地球化学特征及矿床成因

    Institute of Scientific and Technical Information of China (English)

    李剑锋; 王可勇; 陆继胜; 张雪冰; 权鸿雁; 王承洋; 魏良民

    2015-01-01

    Hongling lead-zinc deposit is one of the representative large deposits in southeastern Inner Mongolia.Presently,there’s very little research on geochemical characteristics and evolution of ore-form fluids,and ore genesis.The fluid inclusions are systemly re-searched in this paper,The results show that there are three types of primary fluid inclusions in garnet of garnet-skarn stage (Ⅰ)inclu-ding halite-bearing three-phase,aqueous two-phase as well as vapor-rich two-phase;there are two types of primary fluid inclusions in quartz of stage (Ⅱ)including aqueous two-phase as well as vapor-rich two-phase.It is found in our microthermometric study that the ore-forming fluid is of high temperature,high salinity and immiscible NaCl-H2 O type solutions and the boiling process plays important role in the precipitation of Pb,Zn,and Cu.Quartz of mineralization stage Ⅲ to Ⅳ of quartz-sulfide epochs contains only aqueous two-phase of fluid inclusions.The homogenization temperature of this type of fluid inclusions is obviously lower than that of skarn epoch, while the salinity does not obviously change.The homogenization temperatures of fluid inclusions show a rising trend with salinities dis-playing a dropping trend of stage Ⅳ,and it may be caused by adding of high temperature,low salinity type fluid.The dropping of homogenization temperatures and salinities of ore-forming fluids from mineralization stages Ⅴ to Ⅵ suggests that meteoric water contin-uously joining into the ore-forming fluid.Overall,the ore-forming fluids of quartz-sulfide epoch is of medium-low temperature and low salinity NaCl-H2 O type solutions.C,H,O isotope study of fluid inclusions shows that the ore-forming fluids of skarn epoch mainly came from magmatic water and that of quartz-sulfide epoch came from mixed magmatic water and meteoric water,whereas at the latest stage of mineralization,the ore-forming fluids mainly came from meteoric water.The study of S,Pb isotopes implies that the ore

  20. Salt tectonics and associated fluid migration and entrapment in the western part of the Norwegian-Danish Basin

    Science.gov (United States)

    Sørig, Simon A.; Clausen, Ole R.; Andresen, Katrine J.

    2016-04-01

    The western part of the Norwegian-Danish Basin is part of the Northern Permian Basin and encompasses a variety of Zechstein salt structures (pillows, rollers, diapirs and salt walls). The area has been studied for decades with respect to HC prospectively associated to salt structures as well a focus area for studies on conceptual evolution of salt structures and faults associated with the salt structures. Previous local studies on fluid migration and Direct Hydrocarbon Indicators (DHI's) in the area show a close relation between halo kinetics and local fluid migration. In the present study we have used3D seismic data (approximately 3500 km2) to identify and describe A: large diapirs which have been active until the youngest Cenozoic, B: medium sized diapirs being active until the early Cenozoic, C: salt relicts creating small non active pillows, and D: small satellite structures related to type A. The salt structures are evenly distributed across the studied area, and we conclude that the structures were initiated during the late Triassic due to depositional controlled differential loading combined with differential subsidence. DHI's are identified at various stratigraphic and structural settings associated to the salt structures and each structure type has different types of DHI's associated. The DHIs observed at the type A and B diapirs are located above or at the stem of the diapirs and are here interpreted as classic structural hydrocarbon traps associated with rising salt deforming the strata. However, the DHI's associated to type C salt pillows have a relatively small lateral extent, stratigraphically restricted to the Mesozoic succession; they are located above the apex of the pillow and have in general a seismically disturbed zone located beneath the DHI. The seismically disturbed zone resembles gas chimneys, but may also be related to minor deformation of the Mesozoic strata overlying the type C pillows. A biogenic origin of the gas in at least some of the

  1. Basin-scale transport of heat and fluid induced by earthquakes

    Science.gov (United States)

    Wang, C.; Manga, M.; Wang, L.; Chen, C.

    2013-12-01

    Large earthquakes are known to cause widespread changes in groundwater flow at distances thousands of kilometers away from the epicenter, yet their relation to subsurface transport is unknown. Since groundwater flow is effective in transporting subsurface heat, studies of earthquake-induced changes in groundwater temperature may be useful for better understanding earthquake-induced heat transport. Here we report systematic changes in groundwater temperature after the 1999 Mw 7.6 Chi-Chi earthquake in central Taiwan, recorded by a dense network of monitoring wells over a large (1,800 km2) alluvial fan near the epicenter. The data documented a clear trend of increase from negative changes (temperature decrease) near the upper rim of the fan near the ruptured fault to positive changes (temperature increase) near the coast. Analysis of the data reveals a hitherto unknown system of earthquake-triggered basin-wide groundwater flow, which scavenges geothermal heat from depths, changing groundwater temperature across the basin. The newly identified earthquake-triggered groundwater flow may have significant implications on post-seismic groundwater supply and quality, contaminant transport, underground repository safety, and hydrocarbon production.

  2. The uranium ore deposits in Ciudad Rodrigo Phyllites. about the possibility of new deposits

    International Nuclear Information System (INIS)

    The main features of the genesis of uranium deposits of the Fe mine type, are discussed in this paper. Pitchblende ore is related with phyllites bearing organic material and with geomorphological level, fossilized by eocene sediments. As a result, new uranium ore deposits are possible under Ciudad Rodrigo tertiary basin, tertiary cover depth being little more than three hundred feet. (Author)

  3. Types, Evolution and Pool-Controlling Significance of Pool Fluid Sources in Superimposed Basins: A Case Study from Paleozoic and Mesozoic in South China

    Institute of Scientific and Technical Information of China (English)

    Xu Sihuang; Mei Lianfu; Yuan Caiping; Ma Yongsheng; Guo Tonglou

    2007-01-01

    Having multiple tectonic evolution stages, South China belongs to a superimposed basin in nature. Most marine gas pools became secondary pools. The pool fluid sources serve as the principal pool-controlling factors. On the basis of eight typical petroleum pools, the type, evolution in time-space,and the controlling of petroleum distribution of pool fluid sources are comprehensively analyzed. The main types of pool fluid sources include hydrocarbon, generated primarily and secondly from source rocks, gas cracked from crude oil, gas dissolved in water, inorganic gas, and mixed gases. In terms of evolution, the primary hydrocarbon was predominant prior to Indosinian; during Indosinian to Yenshanian the secondary gas includes gas cracked from crude oil, gas generated secondarily, gas dissolved in water, and inorganic gas dominated; during Yenshanian to Himalayan the most fluid sources were mixed gases. Controlled by pool fluid sources, the pools with mixed gas sources distributed mainly in Upper Yangtze block, especially Sichuan (四川) basin; the pools with primary hydrocarbon sources distributed in paleo-uplifts such as Jiangnan (江南), but most of these pools became fossil pools; the pools with secondary hydrocarbon source distributed in the areas covered by Cretaceous and Eogene in Middle-Lower Yangtze blocks, and Chuxiong (楚雄), Shiwandashan (十万大山), and Nanpanjiang (南盘江) basins; the pools with inorganic gas source mainly formed and distributed in tensional structure areas.

  4. Sill intrusion driven fluid flow and vent formation in volcanic basins: Modeling rates of volatile release and paleoclimate effects

    Science.gov (United States)

    Iyer, Karthik; Schmid, Daniel

    2016-04-01

    Evidence of mass extinction events in conjunction with climate change occur throughout the geological record and may be accompanied by pronounced negative carbon isotope excursions. The processes that trigger such globally destructive changes are still under considerable debate. These include mechanisms such as poisoning from trace metals released during large volcanic eruptions (Vogt, 1972), CO2 released from lava degassing during the formation of Large Igneous Provinces (LIPs) (Courtillot and Renne, 2003) and CH4 release during the destabilization of sub-seafloor methane (Dickens et al., 1995), to name a few. Thermogenic methane derived from contact metamorphism associated with magma emplacement and cooling in sedimentary basins has been recently gaining considerable attention as a potential mechanism that may have triggered global climate events in the past (e.g. Svensen and Jamtveit, 2010). The discovery of hydrothermal vent complexes that are spatially associated with such basins also supports the discharge of greenhouse gases into the atmosphere (e.g. Jamtveit et al., 2004; Planke et al., 2005; Svensen et al., 2006). A previous study that investigated this process using a fluid flow model (Iyer et al., 2013) suggested that although hydrothermal plume formation resulting from sill emplacement may indeed release large quantities of methane at the surface, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative δ13C excursions observed in the fossil record over short time scales observed in the fossil record. Here, we reinvestigate the rates of gas release during sill emplacement in a case study from the Harstad Basin off-shore Norway with a special emphasis on vent formation. The presented study is based on a seismic line that crosses multiple sill structures emplaced around 55 Ma within the Lower Cretaceous sediments. A single well-defined vent complex is interpreted above the termination of the

  5. 西藏邦铺钼铜矿区He、Ne和Ar同位素及成矿流体示踪%He, Ne and Ar Isotopic Composition and Origin of Ore-forming Fluids of Bangpu Mo-Cu Mine Area, Tibet

    Institute of Scientific and Technical Information of China (English)

    温泉; 温春齐; 霍艳; 周雄; 费光春; 黄于鉴

    2012-01-01

    Bangpu Cu—Mo ore area is located in the east oi the Gangdisi porphyry copper zone in Tibet. It is a typical copper-molybdenum metal ore deposit with large type porphyry. Noble gas isotopes in the fluid inclusions in the molybdenite of Mo-Cu ore body and in the pyrite of Pb-Zn ore body were tested. The results show that the contents of 4He, 20Ne, 40Ar, 34Kr and 132Xe in the fluid inclusions of the molybdenite in Mo-Cu ore body are higher than these of the pyrite in Pb-Zn ore body. The partial ratio in the former is lower than that in the latter, such as 3He/4He is 0.347 and 5.80, 21Ne/22Ne is 0.027 2 and 0.045 8, 40Ar/36Ar is 381.9 and 743.3, respectively. It shows that the fluid of the deposit may belong to crust-mantle mixed source, the fluid source of molybdenite maybe come from the crust-derived fluid or atmospheric water, pyrite fluid source mayhe come from mantle -derived fluid. This result is consistent with the investigation of the quartz fluid inclusions of hydrogen and oxygen isotopes.%邦铺钼铜多金属矿区位于西藏冈底斯斑岩铜矿带东段,是典型的大型斑岩型钼铜多金属矿床.对该矿床钼铜矿体和铅锌矿体的辉钼矿和黄铁矿流体包裹体进行了稀有气体同位素测试.测试显示,辉钼矿流体包裹体中4He,20Ne,40Ar,84Kr和132Xe含量均高于铅锌矿体的黄铁矿;但部分比值前者却低于后者,3He/4He分别为0.347和5.80,21Ne/22Ne分别为0.0272和0.0458,40Ar/36Ar分别为381.9和743.3.研究认为,该矿床流体可能属壳幔混源,辉钼矿流体来源以壳源流体或大气水为主,黄铁矿流体来源以幔源流体为主.这与石英矿物流体包裹体氢氧同位素研究一致.

  6. Fluid Chemistry Dynamics Before and After Fire in the Jemez River Basin Critical Zone Observatory

    Science.gov (United States)

    Chorover, J.; Perdrial, J. N.; Field, J. P.; Pelletier, J. D.; Pohlmann, M. A.; Losleben, M. V.; Lasharr, K.; Amistadi, M.; Brooks, P. D.; McIntosh, J. C.; Meixner, T.; Gallery, R.; Rich, V. I.; Rasmussen, C.; Schaap, M. G.; Breshears, D. D.

    2013-12-01

    The largest wildfire in New Mexico state history (prior to the Whitewater-Baldy fire of 2012) burned the eastern portion of the Jemez River Basin Critical Zone Observatory (JRB CZO) in June-July 2011. This Los Conchas fire burned large stands of ponderosa pine and mixed conifer (MC) forest within the East Fork Jemez River watershed generating massive post-fire erosion. We asked the question: What are the implications of wildfire on pulsed carbon and other bio-active element redistributions in impacted soils and catchments? As soon as possible following the fire, our research group installed sensor and sampler instrumentation in soil profiles in an intensively burned zero order basin (ZOB), enabling the initiation of comparisons to a similarly instrumented, unburned MC ZOB. The signal of biomass combustion was propagated through soil and stream. Post-burn solute fluxes were dominated by highly-aromatic character DOM, as well as elevated DIC, sulfate, chloride and non-hydrolyzing cation (Ca, Mg, K) concentrations deriving from biomass combustion. Supporting an apparent trend of increasing wildfire in western montane forests, the Thompson Ridge wildfire burned MC forest throughout much of the western previously unburned portion of the Valles Caldera National Preserve in June 2013, including the (until then) "unburned" MC ZOB sites comprising CZO sensor and sampler network arrays. Post-burn soil samples were collected for geochemical, physical, and microbial composition characterizations. Solute and gas fluxes were monitored in situ to compare CZ response following this high intensity burn to three years of pre-burn data. Results indicate that the post-fire pulse of water soluble, biomass-derived ions and carbon into underlying and downslope soils is generating landscape-scale element distribution that could affect recolonization by biota in the ensuing secondary succession.

  7. Light Hydrocarbon Composition of Fluid Inclusions and Its Constraints on Ore Genesis:A Case Study of the Songxi Ag(Sb) Deposit,Eastern Guangong%流体包裹体轻烃有机气体组成及对矿床成因的制约——以嵩溪大型银(锑)矿为例

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Songxi is a newly-discovered large-size Ag(Sb) deposit.Using a suite of high vacuum quardrupole gas mass spectrometer systems,the authors recognized many kinds of light hydrocarbons in fluid inclusions of minerals.These hydrocarbons are mainly composed of C1-C4 saturated alkanes,while the contents of C2-C4 unsaturated alkenes and aromatic hydrocarbons are quite low,suggesting that the metallogenic processes seem not to have been affected by magmatic activities.Chemical equilibrium studies show that these hydrocarbons may be mixture of organic gases generated by microorganism activity and thermal cracking of Type Ⅱ kerogens (kukersite) in sedimentary host rocks,and the former may constitute more than two-thirds,implying that microorganism might have played an important role in the metallogenesis.The equilibrium temperature of the latter is about 300℃,which is much higher than the geothermal temperature at the estimated depth of metallogenesis.Thus,the hight hydrocarbons generated by thermal cracking of kerogens probably originated in the deep part of the sedimentary basins and then migrated through a long distance to the shallow position of the basin.The analystical data presented in this paper support from ore aspect the genetic model that Songxi may be a sedimentary hot brine transformed deposit instead of being a submarine basic volcanic exhalation and low-medium temperature volcanic hydrothermal fluid filling deposit proposed by most previous researchers.%嵩溪银(锑)矿是一个新发现的大型独立银矿。矿物流体包裹体超高真空四极气相质谱系统测定显示,该矿成矿流体中存在多种轻烃有机气体,主要由C1-C4饱和烷烃组成,仅含微量C2-C4不饱和烯烃和芳烃,说明成矿过程基本未受到高温岩浆作用的影响。化学平衡研究表明,这些轻烃气体为微生物成因和沉积岩围岩中Ⅱ类干酪根热解成因的混合气体,其中前者占2/3以上,说明成矿中微生物活

  8. Infiltration of late Palaeozoic evaporative brines in the reelfoot rift: A possible salt source for Illinois Basin formation waters and MVT mineralizing fluids

    Science.gov (United States)

    Rowan, E.L.; De Marsily, G.

    2001-01-01

    Salinities and homogenization temperatures of fluid inclusions in Mississippi Valley-type (MVT) deposits provide important insights into the regional hydrology of the Illinois basin/Reelfoot rift system in late Palaeozoic time. Although the thermal regime of this basin system has been plausibly explained, the origin of high salinities in the basin fluids remains enigmatic. Topographically driven flow appears to have been essential in forming these MVT districts, as well as many other districts worldwide. However, this type of flow is recharged by fresh water making it difficult to account for the high salinities of the mineralizing fluids over extended time periods. Results of numerical experiments carried out in this study provide a possible solution to the salinity problem presented by the MVT zinc-lead and fluorite districts at the margins of the basin system. Evaporative concentration of surface water and subsequent infiltration into the subsurface are proposed to account for large volumes of brine that are ultimately responsible for mineralization of these districts. This study demonstrates that under a range of geologically reasonable conditions, brine infiltration into an aquifer in the deep subsurface can coexist with topographically driven flow. Infiltration combined with regional flow and local magmatic heat sources in the Reelfoot rift explain the brine concentrations as well as the temperatures observed in the Southern Illinois and Upper Mississippi Valley districts.

  9. Iron Ore Spies

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China has begun to attack industrial spies to prevent state security from being compromised Four employees of Rio Tinto, including Hu Shitai, former head of Rio’s Shanghai office and Rio’s China iron ore division, were detained in Shanghai on July 5, on charges of espionage. A senior executive of

  10. Petroleum migration and mixing in the northwestern Junggar Basin (NW China): constraints from oil-bearing fluid inclusion analyses

    Energy Technology Data Exchange (ETDEWEB)

    Jian Cao; Suping Yao [Nanjing University (China). Dept. of Earth Sciences; Zhijun Jin [Exploration and Production Research Institute, Beijing (CN)] (and others)

    2006-07-15

    Abundant oil-bearing fluid inclusions are present in four reservoir sandstone samples from the slope and fault zone areas in the northwestern margin of the Junggar Basin (NW China). Free oil in intergranular pores, adsorbed oil on grain surfaces, and petroleum in inclusions hosted by mineral grains of these samples were analyzed by gas chromatography and gas chromatography-mass spectrometry. Analytical results indicate similar biomarker distributions in the three bitumen fractions of the samples collected from the slope area, which correlate well with characteristic of the source rocks in the Lower Permian Fengcheng Formation. This is in contrast to the fault zone, where the three bitumen fractions vary significantly in their geochemical signatures, suggesting that all of the three Permian source sequences rocks (including the Lower Permian Jiamuhe and Fengcheng formations, and the Middle Permian Lower Wuerhe Formation) have been mature and contributed to the oils in the fault zone. The presence of an unresolved hydrocarbon hump and a full range of unaltered n-alkanes in the gas chromatograms of samples collected from the fault zone indicate an earlier hydrocarbon biodegradation and subsequent injection of fresh oils, distinctly different from that in the slope area. Petrographic and microthermometric investigations of oil-bearing fluid inclusions suggest a single oil charge in the slope area (to the Lower Triassic reservoir, occurring during the Late Triassic to Early Jurassic time). In the fault zone, oil migration and mixing took place mainly during the Late Triassic to Early Jurassic and Cretaceous, followed by gas migration in the Tertiary period. The different petroleum migration and mixing histories in the slope and fault zones are attributed to the effect of fault-controlled oil and gas migration. (author)

  11. Physical-chemical conditions of ore deposition

    Science.gov (United States)

    Barton, Paul B.

    Ore deposits form under a wide range of physical and chemical conditions, but those precipitating from hot, aqueous fluids-i.e. the hydrothermal deposits-form generally below 700°C and at pressures of only 1 or 2 kbar or less. Natural aqueous fluids in rocks may extract metal and sulfur from a variety of rock types or may acquire them as a residual heritage from a crystallizing silicate magma. Ore-forming hydrothermal fluids never appear as hot springs (except in deep, submarine situations) because they boil, mix with surface waters, and cool, thereby losing their ore-bearing ability before reaching the surface. Mineral systems function as chemical buffers and indicators just as buffers and indicators function in a chemical laboratory. By reading the record written in the buffer/indicator assemblages of minerals one can reconstruct many aspects of the former chemical environment. By studying the record of changing conditions one may deduce information regarding the processes functioning to create the succession of chemical environments and the ore deposits they represent. The example of the OH vein at Creede, Colorado, shows a pH buffered by the K-feldspar + muscovite + quartz assemblage and the covariation of S 2 and O 2 buffered by the assemblage chlorite + pyrite + quartz. Boiling of the ore fluid led to its oxidation to hematite-bearing assemblages and simultaneously produced an intensely altered, sericitic capping over the vein in response to the condensation of vapors bearing acidic components. The solubility of metals as calculated from experimental and theoretical studies of mineral solubility appears too low by at least one or two powers of ten to explain the mineralization at Creede. In contrast to Creede where the mineral stabilities all point to a relatively consistent chemistry, the Mississippi Valley type deposits present a puzzle of conflicting chemical clues that are impossible to reconcile with any single equilibrium situation. Thus we must

  12. Temporal evolution of magmatic-hydrothermal systems in the Manus Basin, Papua New Guinea: Insights from vent fluid chemistry and bathymetric observations

    Science.gov (United States)

    Reeves, E. P.; Thal, J.; Schaen, A.; Ono, S.; Seewald, J.; Bach, W.

    2015-12-01

    The temporal evolution of hydrothermal fluids from back-arc systems is poorly constrained, despite growing evidence for dynamic magmatic-hydrothermal activity, and imminent commercial mining. Here we discuss surveys of diverse vent fluids from multiple hydrothermal fields in the Manus back-arc basin, Papua New Guinea, sampled in 2006 and 2011. Effects of host rock composition, and dynamic magmatic volatile inputs on fluid chemistry are evaluated to understand changes in these systems. Highly acidic and SO4-rich moderate temperature fluids (~48-215°C), as well as SO4-poor black smoker fluids (up to 358°C), were collected at the PACMANUS, SuSu Knolls and DESMOS areas in 2006 and 2011. Acidic, milky white SuSu and DESMOS fluids, rich in elemental S and SO4, exit the seafloor with Na, K, Mg, and Ca diluted conservatively up to 30% relative to seawater, implying subsurface mixing of seawater with SO2-rich aqueous fluids exsolved from magma, analogous to subaerial fumarole discharge. SO2 disproportionation during cooling and mixing of magmatic fluids contributes acidity, SO4, H2S and S(0)(s), as well as widespread S outcrops on the seafloor. Nearby black smoker fluids indicate entrainment and reaction of magmatic fluid into convecting fluids at depth, and additional hybrid-type fluids appear to consist of evolved seawater and unreacted magmatic fluid SO2 derivatives. Fluids at DESMOS in 2006 indicate increased magmatic SO2 relative to 1995, despite constant low venting temperatures (~120°C). In contrast, dramatic changes in bathymetry and seafloor morphology point to substantial continuous eruption of volcaniclastic material between 2006 and 2011 at SuSu Knolls, burying fumarolic vents from 2006. Compositions of new 2011 acidic, sulfate-rich fluids there suggest reaction with less altered, fresher rock. At the PACMANUS area, farther from the arc, direct magmatic degassing to the seafloor is not occurring presently, but entrainment and reaction of similar acid

  13. Diagenetic Reactions in Reservoir Strata and Geochemical Properties of Pore Fluid and Its Origin in Songlian Basin

    Institute of Scientific and Technical Information of China (English)

    楼章华; 蔡希源; 等

    1998-01-01

    The reservoirs of the SOngliao Basin are composed of typical unstable sandstones,with high percentages of volcanic fragments and feldspar,In the course of sedimentation and burying,a series of physical and chemical reactions took place between minerals and pore water and water-rock reactions and ion exchange caused changes in ion assemblage of pore water,Hydration-hydrolysis,dissolution and the albitization of feldspar made many ions free from their framework and inter into the pore water,and induced the precipitation of a large amount of authigenic minerals such as smectite and chlorite,During the diagenesis of sandstone.diagenetic reactions involved several stages with increasing depth,and so did the precipitation of authigenic minerals and the transformaiton of minerals.The migration of ions is related with the precipitation,transformation and dissolution of authigenic minerals.Thus,to deepen our study on sandstone diagenesis is an important link for the analysis of ion migration in the evolution of pore water ,the origin and evolution of pore water could be tracked in terms of the geochemistry of fluid inclusions in authigenic minerals.And the isotopic composition of the authigenic mineral calcite can provide its genetic information.

  14. Dose calculations for intakes of ore dust

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, R.S

    1998-08-01

    This report describes a methodology for calculating the committed effective dose for mixtures of radionuclides, such as those which occur in natural radioactive ores and dusts. The formulae are derived from first principles, with the use of reasonable assumptions concerning the nature and behaviour of the radionuclide mixtures. The calculations are complicated because these `ores` contain a range of particle sizes, have different degrees of solubility in blood and other body fluids, and also have different biokinetic clearance characteristics from the organs and tissues in the body. The naturally occurring radionuclides also tend to occur in series, i.e. one is produced by the radioactive decay of another `parent` radionuclide. The formulae derived here can be used, in conjunction with a model such as LUDEP, for calculating total dose resulting from inhalation and/or ingestion of a mixture of radionuclides, and also for deriving annual limits on intake and derived air concentrations for these mixtures. 15 refs., 14 tabs., 3 figs.

  15. Geochemistry of formation waters from the Wolfcamp and “Cline” shales: Insights into brine origin, reservoir connectivity, and fluid flow in the Permian Basin, USA

    Science.gov (United States)

    Engle, Mark A.; Reyes, Francisco R.; Varonka, Matthew S.; Orem, William H.; Lin, Ma; Ianno, Adam J.; Westphal, Tiffani M.; Xu, Pei; Carroll, Kenneth C.

    2016-01-01

    Despite being one of the most important oil producing provinces in the United States, information on basinal hydrogeology and fluid flow in the Permian Basin of Texas and New Mexico is lacking. The source and geochemistry of brines from the basin were investigated (Ordovician- to Guadalupian-age reservoirs) by combining previously published data from conventional reservoirs with geochemical results for 39 new produced water samples, with a focus on those from shales. Salinity of the Ca–Cl-type brines in the basin generally increases with depth reaching a maximum in Devonian (median = 154 g/L) reservoirs, followed by decreases in salinity in the Silurian (median = 77 g/L) and Ordovician (median = 70 g/L) reservoirs. Isotopic data for B, O, H, and Sr and ion chemistry indicate three major types of water. Lower salinity fluids (100 g/L), isotopically heavy (O and H) water in Leonardian [Permian] to Pennsylvanian reservoirs (2–3.2 km depth) is evaporated, Late Permian seawater. Water from the Permian Wolfcamp and Pennsylvanian “Cline” shales, which are isotopically similar but lower in salinity and enriched in alkalis, appear to have developed their composition due to post-illitization diffusion into the shales. Samples from the “Cline” shale are further enriched with NH4, Br, I and isotopically light B, sourced from the breakdown of marine kerogen in the unit. Lower salinity waters (3 km depth), which plot near the modern local meteoric water line, are distinct from the water in overlying reservoirs. We propose that these deep meteoric waters are part of a newly identified hydrogeologic unit: the Deep Basin Meteoric Aquifer System. Chemical, isotopic, and pressure data suggest that despite over-pressuring in the Wolfcamp shale, there is little potential for vertical fluid migration to the surface environment via natural conduits.

  16. Geochemistry and ore prospecting

    International Nuclear Information System (INIS)

    Applied geochemistry is a new technique which helps the geologist in detecting ore deposits. Some deposits, even when they are covered with rather thick surface structures, form around these zones where the infinitesimal content of some elements of soils or waters is notably different. These 'anomalies' may be contemporaneous to the deposit-structure (primary dispersion) or may have occurred later (secondary dispersion). Various factors rule these anomalies: ore-stability, soil homogeneity, water conditions, topography, vegetation, etc... Applied geochemistry is in fact the study of analysis techniques of metal traces in soils as well as the geological interpretation of observed anomalies. This report gives practical data on sampling methods, yields, costs and also on special problems of uranium geochemistry. (author)

  17. Large-scale Migration of Fluids toward Foreland Basins during Collisional Orogeny:Evidence from Triassic Anhydrock Sequences and Regional Alteration in the Middle-Lower Yangtze Area

    Institute of Scientific and Technical Information of China (English)

    HOU Zengqian; YANG Zhusen; LI Yinqing; ZENG Pusheng; MENG Yifeng

    2004-01-01

    The middle-lower Yangtze area underwent a series of complex tectonic evolution, such as Hercynian extensional rifting, Indosinian foreland basining, and Yanshanian transpression-transtension, resulting in a large distinctive Cu-Fe-Au metallogenic belt. In the tectonic evolution, large-scale migration and convergence of fluids toward foreland basins induced during the collisional orogeny of the Yangtze and North China continental blocks were of vital importance for the formation of the metallogenic belt. Through geological surveys of the middle-lower Yangtze area,three lines of evidence of large-scale fluid migration are proposed: (1) The extensive dolomitic and silicic alteration penetrating Cambrian-Triassic strata generally occurs in a region sandwiched between the metallogenic belt along the Yangtze River and the Dabie orogenic belt, and in the alteration domain alternately strong and weak alteration zones extend in a NW direction and are controlled by the fault system of the Dabie orogenic belt; it might record the locus of the activities of long-distance migrating fluids. (2) The textures and structures of very thick Middle-Lower Triassic anhydrock sequences in restricted basins along the river reveal the important contribution of the convergence of regional hot brine in restricted basins and the chemical deposition or their formation. (3) Early-Middle Triassic syndepositional iron carbonate sequences and Fe-Cu-Pb-Zn massive sulfide deposits alternate with anhydrock sequences or are separated from the latter, but all of them occur in the same stratigraphic horizon and are intimately associated with each other,being the product of syndeposition of high-salinity hot brine. According to the geological surveys, combined with previous data, the authors propose a conceptual model of fluid migration-convergence and mineralization during the Dabie collisional orogeny.

  18. Fault-related CO2 degassing, geothermics, and fluid flow in southern California basins---Physiochemical evidence and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Boles, James R. [Univ. of California, Santa Barbara, CA (United States); Garven, Grant [Tufts Univ., Medford, MA (United States)

    2015-08-04

    Our studies have had an important impact on societal issues. Experimental and field observations show that CO2 degassing, such as might occur from stored CO2 reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.

  19. Evidence of slumping/sliding in Krishna-Godavari offshore basin due to gas/fluid movements

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.; Dewangan, P.; Ramana, M.V.; Mazumdar, A.; Karisiddaiah, S.M.; Ramya, E.R.; Sriram, G.

    The Krishna-Godavari (KG) offshore basin is one of the promising petroliferous basins of the eastern continental margin of India. Drilling in this basin proved the presence of gas hydrate deposits in the shallow marine sediments beyond 750 m water...

  20. Processing of lateritic ores

    International Nuclear Information System (INIS)

    Highly weathered or lateritic ores that contain high proportions of fine clay minerals present specific problems when they are processed to extract uranium. Of perhaps the greatest significance is the potential of the fine minerals to adsorb dissolved uranium (preg-robbing) from leach liquors produced by processing laterites or blends of laterite and primary ores. These losses can amount to 25% of the readily soluble uranium. The clay components can also restrict practical slurry densities to relatively low values in order to avoid rheology problems in pumping and agitation. The fine fractions also contribute to relatively poor solid-liquid separation characteristics in settling and/or filtration. Studies at ANSTO have characterised the minerals believed to be responsible for these problems and quantified the effects of the fines in these types of ores. Processing strategies were also examined, including roasting, resin-in-leach and separate leaching of the laterite fines to overcome potential problems. The incorporation of the preferred treatment option into an existing mill circuit is discussed. (author)

  1. Fluid-assisted particulate flow of turbidites at very low temperature: A key to tight folding in a submarine Variscan foreland basin of SW Europe

    Science.gov (United States)

    Marques, F. O.; Burg, J.-P.; Lechmann, S. M.; Schmalholz, S. M.

    2010-04-01

    The problem addressed in this article is how sedimentary formations like turbidites in a foreland basin, which include layers with apparently great competence contrast, can be tightly folded in a regular manner under very low temperature and pressure. This raises two major issues: the rheological behavior of the rocks at the time of folding and the role played by fluids. In order to understand very low temperature folding and the structural evolution of a submarine foreland basin, we carried out detailed structural work in turbidites with alternating sandstone and shale, for which estimated peak temperature conditions were top diagenetic to very low grade metamorphism. Folds are tight to isoclinal, with local collapsed hinges, which implies that the incompetent shale was mobile enough to flow away from strongly flattened areas. We did not find evidence for cataclastic flow or crystal plasticity at mesoscopic and microscopic scales. Other structures (mostly boudins, foliations, conjugate brittle faults, and quartz veins) associated with folds denote anisotropic compaction by fluid extraction during regional shortening. This is possible if the folded rocks were unconsolidated, fluid-saturated sediments. The estimated low peak temperature is consistent with the shale being unlithified. Poorly cemented grains are free to slide past one another under shallow burial or high pore pressure conditions. Following this line of thought, we consider independent particulate flow assisted by fluids under very low confining pressure (bean bag analogy) as the rock deformation mechanism active during the described intense folding. Similar deformation is likely occurring (and has occurred) in other submarine accretionary wedges.

  2. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  3. Evolution of ore forming fluid of Daping gold deposit in Ailaoshan tectonic zone, Southeast Tibet%青藏高原东南缘哀牢山大坪金矿成矿流体演化

    Institute of Scientific and Technical Information of China (English)

    朱路华; 戚学祥; 彭松柏; 李志群

    2011-01-01

    Daping gold deposit is a large quartz-vein gold deposit in Ailaoshan tectonic zone, made of north and south fields. Fluid inclusion homogenization temperatures range from 187t to 329t (average is 2811) in north field, and from 168℃ to 338℃ (average is 264℃) in south field, respectively. Corresponding, the δDV-SMOW values range from -70‰to -81‰ and from -71‰to-86‰, and the 518OH2O values rang from 2. 9‰ to 9. 8‰ and from 3. 5‰ to 5. 1‰, respectively. All samples plotted at the field between magmatic water and underground water in the plots of 5D vs. δ18OH2O, and that for north field are near magmatic water area, and for south field are near underground water area. The sulfur isotopic compositions (834 S) for north and south fields are 0. 7‰ ~ 15. 5‰ and 10. 6‰ ~ 15. 8‰, respectively. The vapour compositions in fluid inclusions are H2O, CO2 and N2, with a little of CH4 , C2H2, C2H4, C2H6 and CO. The ion compositions in fluid inclusions are K+ , Na+ , Ca2+ , Cl- and SO42- , with a little of NO3 - , F- , Br- and Mg2-. ESR dating data for quartz in gold-bearing quartz veins from north and south fields are 27. 2 - 29. 1 Ma and 17.3~22. 1Ma, respectively. All above show, that the ore forming fluids are mixing of postmagmatic solution and underground water, from north to south, deep to shallow fields and from earlier to later stage, the contents of the postmagmatic solution and sulfur are decreasing, and that of the underground water is increasing, and the age of minerallization is youngling, gradually.%大坪金矿是青藏高原东南缘哀牢山构造带中的大型石英脉型金矿床,由北矿区和南矿区组成.北矿区和南矿区的成矿流体包裹体均一温度及其氢、氧、硫同位素、气液相成份的测试结果表明其成矿温度为:187~329℃(平均为281℃)和168~338℃(平均为264℃)、氢同位素组成(δDV-SMOW)为:-70‰~-81‰和-71‰~-86‰、氧同位素组成(δ18OH2o)为:2.9‰~9.8

  4. Primary migration and secondary alteration of the Upper Paleozoic gas reservoir in Ordos Basin,China―Application of fluid inclusion gases

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The composition of fluid inclusions(FI)often represents the initial geochemical characteristics of palaeo-fluid in reservoir rock.Influence on composition and carbon isotopic composition of gas during primary migration,reservoir-forming and subsequent secondary alterations are discussed through comparing fluid inclusion gas with coal-formed gas and natural gas in present gas reservoirs in the Ordos Basin.The results show that primary migration of gas has significant effect on the molecular but not on the carbon isotopic composition of methane.Migration and diffusion fractionation took place during the secondary migration of gas in Upper Paleozoic gas reservoir according to carbon isotopic composition of methane in FIs.Composition and carbon isotopic composition of natural gas were nearly unchanged after the gas reservoir forming through comparing the FI gases with the natural gas in present gas reservoir.

  5. Therm odynamics of Diagenetic Fluid and Fluid/Mineral Reactions in the Eogene Xingouzui Formation,Oil Field T,Jianghan Basin

    Institute of Scientific and Technical Information of China (English)

    倪师军; 罗扬棣; 等

    1994-01-01

    This study focuses on the thermodynamics of diagenetic fluid from the Eogene Xingouzui Forma-tion which represents the most important reservoir in Field Oil T in the Jianghan Basin.The meas-ured homegenizagion temperatures(110-139℃)of fluid inclusions in diagenetic minerals fall within the range of 67-155℃ at the middle diagenetic stage .The pressure of diagenetic fluid is estimated at 10.2-56 Mpa .The activity of ions in the fluid shows a tendency of Ca2+>Mg2+>Na+>K+>Fe3+>Fe2+ for cations, and HCO3->SO22->F->Cl->CO22- for anions. For the gaseous facies, there is a tendency of CO2>CO>H2S>CH4>H2. According to the thermodynamic calculations,the pH and Eh of the fluid are 5.86-6.47 and -0.73-0.64V, respectively. As a result of the interaction between such a diagenetic fluid and minerals in the sedi-ments,feldspars were dissolved or alterated by other minerals. The clay mineral kaolinite was instable and hence was replaced by illite and chloritoid.

  6. Intra-field variability in microbial community associated with phase-separation-controlled hydrothermal fluid chemistry in the Mariner field, the southern Lau Basin

    Science.gov (United States)

    Takai, K.; Ishibashi, J.; Lupton, J.; Ueno, Y.; Nunoura, T.; Hirayama, H.; Horikoshi, K.; Suzuki, R.; Hamasaki, H.; Suzuki, Y.

    2006-12-01

    A newly discovered hydrothermal field called the Mariner field at the northernmost central Valu Fa Ridge (VFR) in the Lau Basin was explored and characterized by geochemical and microbiological surveys. The hydrothermal fluid (max. 365 u^C) emitting from the most vigorous vent site (Snow chimney) was boiling just beneath the seafloor at a water depth of 1908 m and two end-members of hydrothermal fluid were identified. Mineral and fluid chemistry of typical brine-rich (Snow chimney and Monk chimney) and vapor-rich (Crab Restaurant chimney) hydrothermal fluids and the host chimney structures were analyzed. Microbial community structures in three chimney structures were also investigated by culture-dependent and - independent analyses. The 16S rRNA gene clone analysis revealed that both bacterial and archaeal rRNA gene communities at the chimney surface zones were different among three chimneys. The bacterial and archaeal rRNA gene communities of the Snow chimney surface were very similar with those in the dead chimneys, suggesting concurrence of metal sulfide deposition at the inside and weathering at the surface potentially due to its large structure and size. Cultivation analysis demonstrated the significant variation in culturability of various microbial components, particularly of thermophilic H2- and/or S-oxidizing chemolithoautotrophs such as the genera Aquifex and Persephonella, among the chimney sites. The culturability of these chemolithoautotrophs might be associated with the input of gaseous energy and carbon sources like H2S, H2 and CH4 from the hydrothermal fluids, and might be affected by phase-separation- controlled fluid chemistry. In addition, inter-fields comparison of microbial community structures determined by cultivation analysis revealed novel characteristics of the microbial communities in the Mariner field of the Lau Basin among the global deep-sea hydrothermal systems.

  7. New isotopic evidence bearing on bonanza (Au-Ag) epithermal ore-forming processes

    Science.gov (United States)

    Saunders, James A.; Mathur, Ryan; Kamenov, George D.; Shimizu, Toru; Brueseke, Matthew E.

    2016-01-01

    New Cu, S, and Pb isotope data provide evidence for a magmatic source of metal(loid)s and sulfur in epithermal Au-Ag deposits even though their ore-forming solutions are composed primarily of heated meteoric (ground) waters. The apparent isotopic discrepancy between ore metals and ore-forming solutions, and even between the ore and associated gangue minerals, indicates two different sources of epithermal ore-forming constituents: (1) a shallow geothermal system that not only provides the bulk of water for the ore-forming solutions but also major chemical constituents leached from host rocks (silica, aluminum, potassium, sodium, calcium) to make gangue minerals and (2) metals and metalloids (As, Te, Sb, etc.) and sulfur (±Se) derived from deeper magma bodies. Isotopic data are consistent with either vapor-phase transport of metal(loids) and sulfur and their subsequent absorption by shallow geothermal waters or formation of metallic (Au, Ag, Cu phases) nanoparticles at depth from magmatic fluids prior to encountering the geothermal system. The latter is most consistent with ore textures that indicate physical transport and aggregation of nanoparticles were significant ore-forming processes. The recognition that epithermal Au-Ag ores form in tectonic settings that produce magmas capable of releasing metal-rich fluids necessary to form these deposits can refine exploration strategies that previously often have focused on locating fossil geothermal systems.

  8. Tracking the source of mineralisation in the Tampere Basin (southern Finland), insights from structure, sedimentology and geophysics studies

    DEFF Research Database (Denmark)

    Moreau, Julien; Torvela, Taija; Kalliomäki, Henrik;

    2013-01-01

    The ancient basins are of a wide interest to geoscientists as they archive the early development of plate tectonics, life, and ore-bearing systems. Several basins, especially those involving volcanic-derived materials, contain ore and mineral deposits. The formation of these ores is often related...

  9. Geochemical and visual indicators of hydrothermal fluid flow through a sediment-hosted volcanic ridge in the Central Bransfield Basin (Antarctica.

    Directory of Open Access Journals (Sweden)

    Alfred Aquilina

    Full Text Available In the austral summer of 2011 we undertook an investigation of three volcanic highs in the Central Bransfield Basin, Antarctica, in search of hydrothermal activity and associated fauna to assess changes since previous surveys and to evaluate the extent of hydrothermalism in this basin. At Hook Ridge, a submarine volcanic edifice at the eastern end of the basin, anomalies in water column redox potential (E(h were detected close to the seafloor, unaccompanied by temperature or turbidity anomalies, indicating low-temperature hydrothermal discharge. Seepage was manifested as shimmering water emanating from the sediment and from mineralised structures on the seafloor; recognisable vent endemic fauna were not observed. Pore fluids extracted from Hook Ridge sediment were depleted in chloride, sulfate and magnesium by up to 8% relative to seawater, enriched in lithium, boron and calcium, and had a distinct strontium isotope composition ((87Sr/(86Sr = 0.708776 at core base compared with modern seawater ((87Sr/(86Sr ≈ 0.70918, indicating advection of hydrothermal fluid through sediment at this site. Biogeochemical zonation of redox active species implies significant moderation of the hydrothermal fluid with in situ diagenetic processes. At Middle Sister, the central ridge of the Three Sisters complex located about 100 km southwest of Hook Ridge, small water column E(h anomalies were detected but visual observations of the seafloor and pore fluid profiles provided no evidence of active hydrothermal circulation. At The Axe, located about 50 km southwest of Three Sisters, no water column anomalies in E(h, temperature or turbidity were detected. These observations demonstrate that the temperature anomalies observed in previous surveys are episodic features, and suggest that hydrothermal circulation in the Bransfield Strait is ephemeral in nature and therefore may not support vent biota.

  10. Large ore-concentrated area of uranium deposits and uranium metellogeny

    International Nuclear Information System (INIS)

    The formation of large ore-concentrated are results from the anomalous concentration of multi-mineral resources and large amount of ore materials during the process of geologic evolution history. Different ore-concentrated areas are characterized by different typical mineral resources and typical ore deposits. By taking uranium deposit as an example, the author recognizes 14 large ore-concentrated areas of uranium deposit in the world, and studies the time-space constraints of large ore-concentrated areas of uranium deposits and their relation with geodynamic evolution, and on the above basis, discusses the unusual concentration of ore elements in large ore-concentrated areas of uranium deposits, as well as proposes the characteristics of 'unusual concentration in certain points and areas' and 'explosion metallogeny in a short period of time' of multiple mineral resources. According to the three basic 'links', i.e. 'source, transportation and precipitation', the author proposes the metallogeny of large ore-concentrated areas of uranium deposits. Of them, the study on the deep-source metallogeny, water-rock intereaction of special alkaline fluid and precipitation environment has made a foundation for the establishment of prospecting model of large uranium ore-concentration areas

  11. Hunting for Iron Ore Bargains

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    One of China’s leading steel mills has turned to smaller mines for long-term, lowcost iron ore supplies china’s oldest steel producer is looking to South America to fulfill its iron ore needs in the face of rising prices from

  12. Paragenetic and minor- and trace-element studies of Mississippi Valley-type ore deposits of the Silesian-Cracow district, Poland

    Science.gov (United States)

    Viets, J.G.; Leach, D.L.; Lichte, F.E.; Hopkins, R.T.; Gent, C.A.; Powell, J.W.

    1996-01-01

    Paragenetic and minor- and trace-element studies were conducted on samples of epigenetic ore and gangue minerals collected from mines and drill core in the Silesian-Cracow (S-C) district of southern Poland. Four discrete mineral suites representing four mineralizing stages can be identified throughout the district. The earliest epigenetic minerals deposited during stage 1 consist of a late dolomite cement together with minor pyrite and marcasite. Stage 2 was the first ore-forming stage and included repetitive deposition of sphalerite and galena in a variety of morphologies. Stage 3 abruptly followed the first ore stage and deposited marcasite and pyrite with variable amounts of late sphalerite and galena. In the samples studied, minerals deposited during stage 3 are predominately marcasite-pyrite with minor sphalerite and galena in the Pomorzany and Olkusz mines, whereas, at the Trzebionka mine, stage 3 mineralization deposited mostly galena and sphalerite with little marcasite or pyrite. Stage 4 minerals include contains barite, followed by calcite, with very minor pyrite and a rare, late granular sphalerite. Compared to other major Mississippi Valley-type (MVT) districts of the world, the Silesian-Cracow district contains sphalerite with the second largest range in Ag concentrations and the largest range in Fe and Cd concentrations of any district. Unlike in other districts, very wide ranges in minor- and trace-element concentrations are also observed in paragenetically equivalent samples collected throughout the district. This wide range indicates that the minor- and trace-element content of the ore-forming environment was highly variable, both spatially and temporally, and suggests that the hydrologic system that the ore fluids traversed from their basinal source was very complex. Throughout the district, a significant increase in Tl, Ge, and As concentrations is accompanied by a lightening of sulfur isotopes between stage 2 and stage 3 minerals. This change

  13. Coontail fluorite rhythmites of southern Illinois: evidence for episodic basin dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, C.A.; Kelly, W.C.; Wilkinson, B.H.

    1985-01-01

    Stratiform coontail ore of the Cave-in-Rock fluorite district, southern Illinois, display conspicuous, rhythmic banded textures similar to those reported in many MVT deposits throughout the world (e.g., east Tennessee, USA; Silesian-Cracow Region, Poland; and northern Baffin Island, Canada). Banding is expressed by the rhythmic alteration of two types of layers: detrital layers of fluorite mottled with particulate gangue dolomite and quartz, and layers of clear, crystalline fluorspar. Both are now composed principally of fluorite but differ in color, fabric and outline. In the past, this rhythmic banding has generally been attributed to fine-scale replacement of a primary host rock stratification or to cyclic replacement of host carbonates by a fluid of oscillating chemistry. Detailed megascopic and microscopic studies of these ores and their carbonate host real that ore bands were not derived by fine-scale in situ limestone replacement. Detrital bands contain hydraulically transported, sorted and graded, allochthonous debris derived by dissolution and disaggregation of host limestone and overlying shale. The banded fabric thus represents a cyclic interplay of chemical and hydraulic processes active during hydrothermal ore mineralization. Coontail ore bodies evidently formed in a hydrothermal spelean system, whose laterally sinuous trace reflects localization of hydrothermal activity where feeder faults intersected relatively impermeable roof-rock shales. The banded nature of these ores testifies to the ability of Mississippi Valley-type hydrothermal solutions to both create and fill their own open spaces. Moreover, the rhythmic nature of coontail ores suggests a prolonged and pulsating mineralization best explained by episodic dewatering of the Illinois Basin.

  14. Evidences of early to late fluid migration from an upper Miocene turbiditic channel revealed by 3D seismic coupled to geochemical sampling within seafloor pockmarks, Lower Congo Basin

    Energy Technology Data Exchange (ETDEWEB)

    Gay, A. [Challenger Division for Seafloor Processes, National Oceanography Centre of Southampton, Southampton (United Kingdom); Lopez, M.; Seranne, M. [Laboratoire Dynamique de la Lithosphere, Universite Montpellier 2, Montpellier (France); Cochonat, P. [Laboratoire Environnements Sedimentaires, Departement Geosciences Marines, IFREMER, Brest (France); Levache, D.; Sermondadaz, G. [TOTAL, Pau (France)

    2006-04-15

    Using high quality 3D seismic data within the Lower Congo Basin (LCB), we have identified pockmarks that are aligned above the sinuous belt of a buried turbiditic palaeo-channel, 1000m beneath the seafloor. Geochemical analyses on cores (GC traces), taken in the centre of four of these pockmarks along this channel, show no clear evidence for migrated oil. But, some features of the GC traces, including elevated baselines (UCM>34{mu}g/g) and a broad molecular weight range of n-alkanes with little odd-even preference, may be interpreted as indicating the presence of thermogenic hydrocarbons in the cores. Seismic profiles show that these pockmarks developed above two main features representative of pore fluid escape during early compaction: (1) closely spaced normal faults affecting the upper 0-800ms TWT of the sedimentary column. This highly faulted interval (HFI) appears as a hexagonal network in plane view, which is characteristic of a volumetrical contraction of sediments in response to pore fluid escape. (2) Buried palaeo-pockmarks and their underlying chimneys seem to be rooted at the channel-levee interface. The chimneys developed during early stages of burial and are now connected to the HFI. This study shows that the buried turbiditic channel now concentrates thermogenic fluids that can migrate through early chimneys and polygonal faults to reach the seafloor within some pockmarks. Using a multidisciplinary approach within the Lower Congo Basin, combining 3D seismic data and geochemical analyses on cores, we trace the fluid history from early compaction expelling pore fluids to later migration of thermogenic hydrocarbons. (author)

  15. Green line fracturing systems fluids in Campos Basin, Brazil; Sistemas de fluidos de fraturamento na Bacia de Campos: evolucao em beneficio do meio ambiente

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Alexandre B. de; Araujo, Cosme J.C. de; Martinho, Flavio M.; Gaspar, Fernando [BJ Services do Brasil, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The constant demand for Services Companies in Oil and Gas Industry to reduce the environmental impacts has led to a race in search of new cleaner technologies. Fluids with low toxicity are the target of research and development by the companies which are committed to ensure the aspects of quality, health, safety and environment from manufacturing up to the use in the final destination of these products. The replacement of these fluids is happening at a larger speed than in the past on the based in two factors: greater awareness on the part of these companies in relation to the environmental and by new environmental laws. The fluids systems used in fracturing operations are not an exception to this rule. Service companies today are in the process of replacing their formulations with systems less aggressive to the environment so-called 'green' systems. In this context the new technological developments of fracturing fluids are of fundamental importance to assist the new environmental requirements of both operators and government regulatory bodies and also to ensure better effectiveness of these products. This paper reports the research, development and application of new environmentally acceptable fracturing fluids technology, reviews the pioneering case histories in offshore operations and the benefits experienced in the Campos Basin - Brazil. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico

    International Nuclear Information System (INIS)

    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

  18. Reservoir quality and diagenetic evolution of Upper Mississippian rocks in the Illinois Basin; influence of a regional hydrothermal fluid-flow event during late diagenesis

    Science.gov (United States)

    Pitman, Janet K.; Henry, Mitchell E.; Seyler, Beverly

    1998-01-01

    Conventional reservoir quality data for more than 300 wells provided by the Illinois and Indiana State Geological Surveys were analyzed to determine the factors governing porosity and permeability in the Upper Mississippian Bethel Sandstone and Cypress Sandstone, two of the principal producing units in the Illinois Basin. In addition, approximately 150 samples of the Bethel Sandstone-Cypress Sandstone interval from about 80 wells in the Illinois Basin were collected for mineralogical and geochemical analysis to reconstruct the burial and diagenetic history and to establish the timing of diagenesis relative to the entrapment of hydrocarbons. One aspect of the study involved linking inorganic and organic diagenesis to late Paleozoic tectonism and hydrothermal fluid-flow events in the region.

  19. Episodic fluid movements in superimposed basin:Combined evidence from outcrop and fluid inclusions of the Majiang ancient oil reservoir,Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Combined evidence from the outcrop and the fluid inclusion assemblage (FIA) analysis indicates that there exist two episodes of fluid flow controlled by the tectonic activity. The first episode was recorded mainly in the reservoir rock of the Honghuayuan Formation,representing the fluid flow of hydrocarbon charging. The second episode occurred mainly along the fault systems,representing the fluid move-ment when the ancient oil reservoir was destroyed. The host mineral morphology,homogeneous tem-perature,and salinity of the FIAs record an episodic fluid movement. Characters of high homogenous temperature,low salinity and a quick temperature variation of the first episode fluid flow may indicate an early-stage fluid eruption,and correspondingly,fine-grained calcite was formed. Temperature of the erupted fluid tended to decrease during its mixing with the upper formation fluid and finally had the same temperature as the upper formation. From then on,the temperature was rather steady and fa-vored the growth of the coarse calcite. Due to this character of the temperature variation of the episodic fluid flow,we can use the homogenous temperature of the FIA of the coarse calcite to date the forma-tion and the destruction time of the Majiang ancient oil reservoir. Episodic fluid flow was known for its inhomogeneous trapping,which resulted in the failure of dating according to the burial history. But taking a close look at its temperature variation,we think that the latest stage of fluid flow,characterized by steady state temperature and grow of the coarser crystals,can be used for dating. It will be of great value if this method is proved to be effective. The formation and the destruction time of the Majiang ancient oil reservoir were dated to be in the Indosinian Period and the late Yanshan-early Hymalayan Period respectively. This conclusion is in great discrepancy with the common accepted idea that the Majiang ancient oil reservoir was formed and destroyed during the

  20. Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

    Science.gov (United States)

    Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

    1996-01-01

    as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

  1. Studies on uranium ore processing

    International Nuclear Information System (INIS)

    For the exploitation of domestic uranium ore deposit, comprehensive studies on uranium ore processing of the Geum-San pit ore are carried out. Physical and chemical characteristics of the Geum-San ore are similar to those of Goe-San ore and the physical beneficiation could not be applicable. Optimum operating conditions such as uranium leaching, solid-liquid separation, solvent extraction and precipitation of yellow cake are found out and the results are confirmed by the continous operation of the micro-plant with the capacity of 50Kg, ore/day. In order to improve the process of ore milling pilot plant installed recently, the feasibility of raffinate-recycle and the precipitation methods of yellow cake are intensively examined. It was suggested that the raffinate-recycle in the leaching of filtering stage could be reduced the environmental contamination and the peroxide precipitation technique was applicable to improve the purity of yellow cake. The mechanism and conditions the third phase formation are thoroughly studied and confirmed by chemical analysis of the third phase actually formed during the operation of pilot plant. The major constituents of the third phase are polyanions such as PMosub(12)Osub(40)sup(3-) or SiMosub(12)Osub(40)sup(4-). And the formation of these polyanions could be reduced by the control of redox potential and the addition of modifier. (Author)

  2. Kinetics of cyaniding of gold comprising ores

    International Nuclear Information System (INIS)

    Present article is devoted to kinetics of cyaniding process of gold comprising ores. Thus in laboratory conditions the researches on leaching of gold and silver from ores of various deposits of Tajikistan by means of cyaniding were conducted. The results of laboratory researches on cyaniding of ores of various deposits are presented. The flowsheet of cyaniding of gold comprising ores was elaborated.

  3. Evidence for metasomatic mantle carbonatitic magma extrusion in Mesoproterozoic ore-hosting dolomite rocks in the middle Kunyang rift, central Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Kunyang rift lying on the western margin of the Yangtze platform is a rare Precambrian Fe-Cu mineralization zone. Wuding- Lufeng basin that is an important part of the zone is located on the west edge in the middle of the rift. The most important ore-hosting rocks are Mesoproterozoic dolomite rocks in the basin controlled by a ring fracture system, which is a fundamental structure of the basin. Plenty of silicate minerals and acicular apatite, feldspar phenocrysts and small vesicular, flown line and flown plane structures, melt inclusion and high temperature fluid inclusion found in most ore-hosting dolomites suggest that this kind of rocks could not be sedimentary dolomite, marble or hydrothermal carbonate rocks. The Zr/Hf and Nb/Ta values of the rocks are identical with those of associated mantle-derived rocks, and vary widely. For the monomineral dolomite, δ18OSMOW‰=+5.99 to +18.4 and δ13CPDB‰=-3.01to+0.94, which fall within the range for all carbonatitic volcanic rocks of the world. As for the accessory minerals, the values of δ18OSMOW‰ of magnetite (=+3.47 to +5.99%0) are close to that of the mantle (<5.7%), and the δ34S‰ values of sulfides (-5.09 to+5.78, averaging+1.50) are close to that of meteorite. For all the ore-bearing dolomite rocks, εNd = +0.19 to +2.27, and the calculated Isr = 0.699143, while for the associated mantle-derived rocks, εNd = +3.18 to +3.72. All the data suggest that the mineral assemblage is not only igneous but also of metasomatic mantle origin. And the presence of acicular apatite indicates that the rocks were formed by magma rapidly cooling. And the phenocryst texture and vesicular, flown and ropy and pyroclastic structures suggest that the igneous rocks were extrusive. Therefore, the ore-bearing dolomite rocks are carbonatitic volcanic rocks. This conclusion implies that most iron and copper ore deposits hosted in the dolomite rocks should be of the carbonatitc type.

  4. Modelling the coupled fluid and heat transport in a geothermal site: First results from Groß Schönebeck, NE-German Basin

    Science.gov (United States)

    Cherubini, Y.; Cacace, M.; Scheck-Wenderoth, M.; Lewerenz, B.

    2010-05-01

    Predicting the temperature distribution in the subsurface becomes increasingly important in the course of recently intensified exploration for geothermal energy. Numerical models considering both the physical processes controlling heat transfer as well as the structural setting of the subsurface are an important option to assess variations in the temperature distribution. The geothermal in-situ laboratory "Groß Schönebeck" located 40 km north of Berlin is one of the key sites of geothermal exploration studies in the North German Basin. 3D numerical simulations of coupled fluid flow and heat transfer processes are carried out to investigate the geothermal field. The Goal of the study is to quantify the impact of variable rock parameters and geological structures on the resulting thermal distribution. The Zechstein salt as a prominent feature in the North German Basin is of particular interest in this context because it locally modifies the geothermal field. Our first attempts to model coupled fluid flow and heat transfer processes confirm the strong impact of the Upper Permian Zechstein salt. Furthermore, our results indicate that conduction is an important heat transfer mechanism below the Middle Triassic layers. Conversely, the more than 3000 m thick and permeable sediments above the Middle Triassic Muschelkalk unit favour the formation of convection cells. Here, especially high degrees of coupling result in remarkable convective heat transport. We assess the sensitivity of these results, and discuss implications for temperature predictions.

  5. An investigation of Water-gas interface migration of the upper Paleozoic gas pool of the Ordos Basin using reservoir fluid inclusion information

    Institute of Scientific and Technical Information of China (English)

    MI Jingkui; XIAO Xianming; LIU Dehan; LI Xianqing; SHEN Jiagui

    2004-01-01

    There is a particular characteristic in the for-mation of the Upper Paleozoic gas pool in the Ordos Basin that is its water-gas interface migrated regional during geological history.However,there has been lack of detailed research on this paper,the formation time of hte fluid inclusions formed in the water-gas transition zone of the gas pool was deduced using their trapping temperatures and combining of the burial with geothermal history of the basin.On the basis of this,the isochrone of water-gas interface migration for the gas pool was mapped .The result shows that the gas pool began to form around the yanan Area at about 165Ma,and then developed and enlarged toward the north direction.The gas pool finally formed at about 129 Ma.Since the basin uplifted from the late Cretaceous and gas supply decreased,the water-gas interface of the gas pool migratec back to the present position.

  6. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

    S. K. Kawatra; T. C. Eisele; K. A. Lewandowski; J. A. Gurtler

    2006-03-31

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.

  7. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

    S. K. Kawatra; T. C. Eisele; J. A. Gurtler; K. Lewandowski

    2005-09-30

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.

  8. NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

    Energy Technology Data Exchange (ETDEWEB)

    S.K. Kawatra; T.C. Eisele; J.A. Gurtler; C.A. Hardison; K. Lewandowski

    2004-04-01

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking.

  9. Shallow burial dolomitisation of Middle-Upper Permian paleosols in an extensional tectonic context (SE Iberian Basin, Spain): Controls on temperature of precipitation and source of fluids

    Science.gov (United States)

    Benito, M. Isabel; De la Horra, Raúl; López-Gómez, José; Barrenechea, José F.; Luque, Javier; Arche, Alfredo

    2011-06-01

    This work is focused on carbonate paleosols developed in three stratigraphic sections (Landete, Talayuelas and Henarejos) of the Middle-Late Permian Alcotas Formation in the SE Iberian Basin. The Alcotas Formation, of alluvial origin, was deposited in semi-connected half-grabens developed during the early stages of the Permian-Triassic rifting stage that affected the Iberian Basin. The studied sections were located in two of these half-grabens, the Henarejos section being much closer to the basin boundary fault than the other two sections. The mineralogy and texture of the carbonate precursor of paleosols in the three studied sections are not preserved because original carbonate is replaced by coarse crystals of dolomite and/or magnesite. Dolomite crystals are typically euhedral, displaying rhombohedral shapes and reddish luminescence, although in the Henarejos section dolomite displays non-planar boundaries and frequently saddle habit. Micas are deformed and adapted to dolomite crystals, which, in turn, are affected by stylolites, suggesting that dolomite precipitated before mechanical and chemical compaction. Carbon and oxygen isotopic compositions of dolomite from the three sections show different values (δ 13C VPDB mean values = - 6.7‰, - 5.5‰ and - 7.5‰; δ 18O VPDB mean values = - 4.0‰; -5.6‰ and - 8.2‰, at Landete, Talayuelas and Henarejos sections, respectively). The 87Sr/ 86Sr ratios are similar in the three sections yielding values between 0.71391 and 0.72213. The petrographic and geochemical features of dolomite in the three studied sections suggest precipitation from similar fluids and during shallow burial diagenesis. Assuming that the minimum temperature for dolomite precipitation in the Henarejos section was 60 °C (as suggested by the presence of non-planar saddle habit), and that the dolomitizing fluid had similar δ 18O values at the three localities, then dolomite in the Talayuelas and Landete sections precipitated at temperatures

  10. Liassic U-Pb age of the Rabejac pitchblende. Isotopic arguments for a Permian uraniferous preconcentration in the Lodeve basin (Herault)

    Energy Technology Data Exchange (ETDEWEB)

    Lancelot, J.; Vella, V.

    Located in the basal part of the Saxonian formations of he Lodeve basin, the massive pitchblendes of the Rabejac ore deposit provide an age of 183 +- 4 Ma (Pb-Pb isochron), consistent with a Liassic mobilization of uranium in southern Massif central previously dated in the U ore deposits of Lodeve (Herault), Bertholene (Aveyron) and Pierres-Plantees (Lozere). This mobilization is related to the circulation of rather hot saline fluids (3-14%, 130-250/sup 0/C) induced by the tectonic phase of continental crust thinning (horsts, grabens, tilted blocks) which preceded the opening of the Ligurian-Piemontais ocean. Using Concordias diagrams we discuss the isotopic composition of the initial lead incorporated into the Rabejac pitchblendes during their cristallization which appears to have been radiogenic. This constitutes the first isotopic argument in favour of a primary U concentration during Permian times in the Lodeve basin.

  11. Agribusiness geothermal energy utilization potential of Klamath and Western Snake River Basins, Oregon. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.

    1978-03-01

    Resource assessment and methods of direct utilization for existing and prospective food processing plants have been determined in two geothermal resource areas in Oregon. Ore-Ida Foods, Inc. and Amalgamated Sugar Company in the Snake River Basin; Western Polymer Corporation (potato starch extraction) and three prospective industries--vegetable dehydration, alfalfa drying and greenhouses--in the Klamath Basin have been analyzed for direct utilization of geothermal fluids. Existing geologic knowledge has been integrated to indicate locations, depth, quality, and estimated productivity of the geothermal reservoirs. Energy-economic needs and balances, along with cost and energy savings associated with field development, delivery systems, in-plant applications and fluid disposal have been calculated for interested industrial representatives.

  12. Fluid inclusion and vitrinite-reflectance geothermometry compared to heat-flow models of maximum paleotemperature next to dikes, western onshore Gippsland Basin, Australia

    Science.gov (United States)

    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. METHODS FOR PALEO-FLUID PRESSURE BUILD-UP IN BASINS%盆地中古流体压力的恢复方法

    Institute of Scientific and Technical Information of China (English)

    王爱国

    2011-01-01

    为了优化古流体压力恢复的技术途径,结合国内外的研究进展对盆地中古流体压力的恢复方法进行了梳理、分析和讨论.恢复方法主要包括泥岩声波时差法、盆地模拟法和流体包裹体法.泥岩声波时差法廉价、快速,但只能恢复最大埋深时的古流体压力,而不适于欠压实以外其他异常压力形成机制;盆地模拟方法可恢复压力的演化史,但其地质模型复杂、参数繁多且不确定性较强,结果的准确度较低;流体包裹体法不必考虑复杂的地质历史和压力形成机制,但目前在绝多数情况下获得的是均一压力或最小捕获压力.进一步研究盐水包裹体的等容线,可提高古流体压力的准确度.每种恢复方法都有其优缺点,对其局限性进行了重点讨论,并指出了发展方向.%In order to optimize the technical methods of paleo-fluid pressure build-up, the methods for paleo-fluid build-up in basins are sorted out, compared, analyzed and discussed based on the research progresses at home and abroad. The build-up methods mainly include mudstone acoustic travel time method, basin modeling method and fluid inclusion method. Mudstone acoustic travel time method is cheap and rapid. However, it can only recover the paleo-fluid pressure at the maximum burial depth, and it is not suitable for other abnormal pressure formation mechanism except for uncompaction. Basin modeling method can recover the evolutionary history. But in this method, its geological model is complex and has many parameters, moreover many of which have relatively high uncertainty, therefore the accuracy of result obtained by this method is relatively low. Fluid inclusion method can get paleo-fluid pressure without considering the complex geologic history and pressure formation mechanism. However, in most cases ,this method can only obtain homogeneous pressure or minimum trapping pressure at present. The further study on isometric line of saline

  14. A new exhalite type——siderite-sericite chert formed in fault-controlled lacustrine basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of geological, fabric, lithographical and mineralogical study, a new exhalite type, called 'siderite-sericite chert' according to its mineral assemblage, was reported for the first time. It was formed in a fault-controlled lacustrine basin and closely associated with sulfide ore characteristic of complex metal assemblage of Sn-Ag-Cu-Pb-Zn. Its geological setting, mineral assemblage, as well as associated ores are quite unique, and therefore worthy of detailed research. In the Dajing deposit, Linxi County, Inner Mongolia, it is this very exhalite that is regarded as a kind of acidic subvolcanic dike till now, and because of this, a genetic model of hydrothermal epigenetic filling by subvolcanic fluid prevails over the Dajing deposit. It is demonstrated again that any geochemical study might be senseless without support of detailed geological and lithographical investigations. This is of particular importance at the present time when one is readily confused by various modern techniques.

  15. Underground leaching of uranium ores

    International Nuclear Information System (INIS)

    Large amounts of low-grade U ore, not worth processing by conventional methods, are to be found at many sites in mine pillars, walls, and backfilling. Many proven deposits are not being mined because the geological conditions are difficult or the U ore is of relatively low grade. Factors such as radioactive emission, radon emanation, and the formation of radioactive dust give rise to health hazards. When U ores are treated above ground, enormous quantities of solid and liquid radioactive waste and mining spoil accumulate. The underground leaching of U is a fundamentally different kind of process. It is based on the selective dissolving of U at the place where it occurs by a chemical reagent; all that reaches the ground surface is a solution containing U, and after extraction of the U by sorption the reagent is used again. The main difficult and dangerous operations associated with conventional methods (excavation; extraction and crushing of the ore; storage of wastes) are avoided. Before underground leaching the ore formation has to be fractured and large ore bodies broken down into blocks by shrinkage stopping. These operations are carried out by advanced machinery and require the presence underground of only a few workers. If the ore is in seams, the only mining operation is the drilling of boreholes. The chemical reagent is introduced under pressure through one set of boreholes, while the U bearing solution is pumped out from another set. The process is monitored with the help of control boreholes. After extraction of the U by sorption, the reagent is ready to be used again. Very few operations are involved and insignificant amounts of dissolved U escape into the surrounding rock formations. Experience has shown that underground leaching reduces the final cost of the U metal, increases productivity, reduces capital expenditure, and radically improves working conditions

  16. Strontium isotope geochemistry of the Lemachang independent silver ore deposit, northeastern Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Sr isotope geochemical studies (the 87Sr/86Sr and ?18O-87Sr/86Sr systems) on the wall rocks and ores from the Lemachang independent Ag deposit in northeastern Yunnan provide strong evidence that the ore-forming fluids had flown through radiogenetically Sr-enriched rocks or strata prior to their entry into the locus of ore precipitation, and water-rock interaction is the main mechanism of Ag ore precipitation. The radiogenetically Sr-enriched source region may be the Proterozoic basement (the Kunyang and Hekou groups). Moreover, the theoretical modeling of the Sr isotopic system indicates that the ore-forming fluids contain as much as 3×10?6 Sr with isotopic composition of Sr being 0.750 and that of oxygen 7.0‰. The ore-forming temperatures were estimated at 150-250℃ for the carbonate rock-type ores and at 200-260℃ for the clastic rock-type.

  17. TWO-DIMENSIONAL AXISYMMETRIC MODELING OF COMBUSTION IN AN IRON ORE SINTERING BED

    DEFF Research Database (Denmark)

    Lafmejani, Saeed Sadeghi; Davazdah Emami, Mohsen; Panjehpour, Masoud;

    2013-01-01

    A twodimensional model, based on conservation of mass, momentum and energy equations, is represented in this paper in which the coke combustion process, for iron ore sintering in a packed bed, is simulated numerically. The aforementioned packed bed consists of iron ore, coke, limestone and moisture...... of species are solved numerically by using a computational fluid dynamics code in a discrete solving domain. Modeling of iron ore sintering has complex and various features like coke combustion, complicated physical changes of solid phase particles and different modes of heat transfer, for example convection...

  18. Characteristics of the ore-forming fluid of typical gold deposits in Xiaoshan area of Henan and their enlightenment to further prospecting works%河南省崤山地区典型金矿床的成矿流体特征及其对进一步找矿工作的启示

    Institute of Scientific and Technical Information of China (English)

    徐文超; 王通; 常云真; 周奇明; 贾慧敏; 赵留升

    2016-01-01

    Xiaoshan area is located inside the middle-west part of Xiaoqinling-Xiaoshan-Xiong’ershan-Waifang-shan Au-Ag-Mo polymetallic metallogenic belt in western Henan.However,the measured reserves of gold ores is far less than that of Xiaoqinling area and eastern Xiong’ershan area.Therefore,the prospecting po-tential in Xiaoshan area attracts great attention of related industrial sectors.Combined with previous work, this paper put forth the theory that the gold ores in the area were predominated by fracture zone alteration rock type and quartz vein type.According to the analysis of typical deposits,the paper concluded that the mineralization of gold ores could be divided into four stages from early to late:(1)quartz-pyrite (arsenopy-rite)stage,(2)pyrite-quartz stage,(3)quartz-polymetallic sulfide stage,and (4)quartz-carbonate stage. Among the four stages,stage (2)and (3)are the main stages of mineralization.The author conducted analy-sis on the content,homogenization temperature and S-H-O-Pb isotope composition of the fluid inclusions in the quartz crystals in each ore-forming stage.It indicates that the fluid was CO 2-rich aqueous fluid with nu-merous dissolved Na+ and Ca2 + ions.The homogenization temperature of fluid inclusions ranges from 243℃to 285℃,and it suggests that the gold deposits in Xiaoshan area are mainly intermediate temperate hydro-thermal deposits being short of fluid inclusions of high temperature stage.The δ34 S value of metal sulfide ranges from -0.5‰ to 5.4‰ and it shows the characteristics of deep source sulfur.And its δ1 8 O H2 O value ranges from 0.1‰ to 9.4‰ and δ1 8 D value ranges from - 134.9‰ to 24.3‰,and it shows that the ore-forming fluid occurs mainly as magmatic water with lesser atmospheric precipitation and metamorphic water. Based on the comparison between outcrop area of granitic intrusive rocks in Xiaoshan area and that in Xiao-qinling area,it appears that the unsatisfactory prospecting results in Xiaoshan area

  19. Geochemical characteristics of the fluid inclusions in the Gangxi Fault Belt, Huanghua Depression, Bohai Bay Basin, China

    Institute of Scientific and Technical Information of China (English)

    DING Wei-wei; DAI Jin-xing; CHU Feng-you; HAN Xi-qiu

    2007-01-01

    We studied the geochemical characteristics of the fluid inclusions in the Ordovician carbonates and the Oligocene Shahejie Formation sandstones from 15 wells in the Gangxi Fault Belt, Huanghua Depression. The fluid inclusions are all secondary with gas/liquid ratio of 5%~10%. Base on Raman they are mainly composed of H2O, CO2 and CH4. The homogenization temperatures, combined with burial and geothermal history of the host rock, indicate that the fluid flows in the Shahejie Formation and the Ordovician carbonates were trapped in Neocene. Using a VG5400 mass spectrometer, the helium isotopic compositions were analyzed. Interpretation of results suggested a significant amount of mantle-derived helium mainly accumulating in the intersections of the NWW trending Xuzhuangzi and NE trending Gangxi faults. The maturity of hydrocarbon decreases from the intersection to the outside pointing out that the fluid related to the NWW trending Xuzhuangzi and NE trending Gangxi faults.These factors implied the fluid inclusions have a close relationship to the local tectonic setting. Gangxi Fault Belt experienced intensive Neo-tectonic activities in Cenozoic. Widespread faulted-depressions and strong volcanic eruptions manifested its tectonic status of extensional stress field. Mantle uplift caused the movement of magma that carried mantle-derived gases and deep heat flows, the deep-rooted tension faults provided the passages for the gases and heat flows to shallow crust levels.

  20. Fluids in distal Zn-Pb-Ag skarns: Evidence from El Mochito, Honduras

    Science.gov (United States)

    Samson, I. M.; Williams-Jones, A. E.; Ault, K.; Gagnon, J. E.; Fryer, B. J.

    2009-05-01

    Zn-Pb-Ag mantos, chimneys, and skarns represent a spectrum of carbonate-hosted sulfide mineral deposits that have been collectively termed carbonate replacement deposits. Most such deposits cannot be related to plutons and, particularly for distal skarns, the role of magmatic versus other fluids (basinal brines and meteoric waters) has been uncertain. The El Mochito Zn-Pb-Ag deposit, Honduras, is an example of a large distal skarn, and comprises mantos and chimneys hosted mainly by limestones of the Early Cretaceous Tepemechin Formation. Previous isotopic studies indicate a magmatic source for the S and Pb and involvement of both magmatic and meteoric fluids in ore formation. The ore is hosted by garnet, magnetite, and pyroxene skarns, which developed sequentially from grandite- to andradite- to magnetite- and hedenbergite- rich skarns. Sphalerite and argentiferous galena occur interstitially to, or replace, the skarn minerals, with Fe- poor sphalerite (S1) principally associated with garnet skarn and Fe-rich (S2) sphalerite associated with pyroxene. Data from primary fluid inclusions show that the salinity of the mineralizing fluids decreased from ˜10-18 wt. % during the formation of garnet skarn and S1 sphalerite to ˜2-13 wt. % during pyroxene skarn formation and S2 sphalerite precipitation. Early, high-salinity fluids (˜33 wt. %) are represented by rare halite-saturated inclusions in garnet. Temperature increased from ˜ 365°C to ˜ 365°C from garnet/S1 sphalerite to pyroxene/S2 sphalerite, assuming a pressure of 500 bars. GC analyses indicate that the total concentrations of COv(2), CH4, and N2 were < 1 mole %. LA-ICPMS analyses were conducted mainly on inclusions in grandite and S1 sphalerite. The principal dissolved elements in the inclusions are Ca and Na, followed by K and Mn. The ore metals, Zn, Pb, and Ag, are present in high concentrations, with median values of 6000, 900, and 50 ppm, respectively. Element concentrations in fluid inclusions hosted

  1. Novel Binders and Methods for Agglomeration of Ore

    Energy Technology Data Exchange (ETDEWEB)

    S. K. Kawatra; T. C. Eisele; K. A. Lewandowski; J. A. Gurtler

    2006-12-31

    Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that will work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking. This project has identified several acid-resistant binders and agglomeration procedures that can be used for improving the energy efficiency of heap leaching, by preventing the ''ponding'' and ''channeling'' effects that currently cause reduced recovery and extended leaching cycle times. Methods have also been developed for iron ore

  2. The distribution and evolution of fluid pressure and its influence on natural gas accumulation in the Upper Paleozoic of Shenmu-Yulin area, Ordos Basin

    Institute of Scientific and Technical Information of China (English)

    WANG; ZhenLiang; CHEN; HeLi

    2007-01-01

    On the basis of measuring the pressure distribution and analyzing its origin in the Carboniferous and Permian of Shenmu-Yulin area, the evolution history of ancient pressure is restored mainly by means of the basin numerical simulation technique, in which the paleo-pressure has been constrained by the compaction restoration and the examination of fluid inclusion temperature and pressure. Then the development and evolution history of abnormal pressure and its effect on gas migration and accumulation are investigated. Studies show that the pressure in southeastern and northwestern parts of studied area is near to hydrostatic pressure, whereas in the remainder vast area the pressure is lower than the hydrostatic pressure, which is caused by difficulty to measure pressure accurately in tight reservoir bed, the calculating error caused by in-coordinate between topography relief and surface of water potential, pressure lessening due to formation arising and erosion. There are geological factors beneficial to forming abnormal high pressure in the Upper Palaeozoic. On the distraction of measured pressure, paleo-pressure data from compaction restoration and fluid inclusion temperature and pressure exa- mining, the evolution history of ancient pressure is restored by the basin numerical simulation technique. It is pointed out that there are at least two high peaks of overpressure in which the highest value of excess pressure could be 5 to 25 MPa. Major gas accumulated in main producing bed of Shanxi Fm (P1s) and lower Shihezi Fm (P2x), because of two-fold control from capillary barrier and overpressure seal in upper Shihezi Fm (P2s). In the middle and southern districts, the two periods of Later Jurassic to the middle of Early Cretaceous, and middle of Later Cretaceous to Palaeocene are main periods of gas migration and accumulation, while they belong to readjustment period of gas reservoirs after middle of Neocene.

  3. Petrophysical analysis of regional-scale thermal properties for improved simulations of geothermal installations and basin-scale heat and fluid flow

    CERN Document Server

    Hartmann, Andreas; Clauser, Christoph

    2008-01-01

    Development of geothermal energy and basin-scale simulations of fluid and heat flow both suffer from uncertain physical rock properties at depth. Therefore, building better prognostic models are required. We analysed hydraulic and thermal properties of the major rock types in the Molasse Basin in Southern Germany. On about 400 samples thermal conductivity, density, porosity, and sonic velocity were measured. Here, we propose a three-step procedure with increasing complexity for analysis of the data set: First, univariate descriptive statistics provides a general understanding of the data structure, possibly still with large uncertainty. Examples show that the remaining uncertainty can be as high as 0.8 W/(m K) or as low as 0.1 W/(m K). This depends on the possibility to subdivide the geologic units into data sets that are also petrophysically similar. Then, based on all measurements, cross-plot and quick-look methods are used to gain more insight into petrophysical relationships and to refine the analysis. Be...

  4. Tectonic ore-controlling in the middle southern segment of Da Hinggan Ling, Northeast China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Studies on geotectonic evolution, regionally geological characteristics and ore-forming and ore-controlling structures have shown that since the Mesozoic the Da Hinggan Ling region has entered the typical intercontinental orogenic stage, which appears to be closely related to mantle plume activities. Da Hinggan Ling is a typical mantle branch structure and possesses obvious magmatic-metamorphic complexes in the core, detachment slip beds in the periphery and overlapped fault depression basins. Moreover, all these are the principal factors leading to ore formation and ore controlling in the region. This paper also further explores the mechanism of mineralization in the middle-southern segment of Da Hinggan Ling,summaries the rules of mineralization, puts forward the models of mineralization and points out the oresearch orientations in the future time.

  5. Implication for horizontally-elongated fluid flow inferred from heat flow measurements in the Iheya-North hydrothermal field, Okinawa Trough back-arc basin

    Science.gov (United States)

    Masaki, Yuka; Kinoshita, Masataka; Kawada, Yoshifumi

    2010-05-01

    The Okinawa Trough is a back-arc basin located in the southwestern part of Japan. It is considered to be in the initial stage of rifting of continental crust, and the activity generates volcanic edifices in this area, accompanied by hydrothermal circulation. The Iheya-North is one of the most active hydrothermal fields among them. As a proposed drilling site for the Integrated ocean Drilling Program, extensive geophysical surveys have been carried out including single-channel seismic imaging, and precise side-scan sonar imaging by using autonomous underwater vehicle 'Urashima' of Japan Agency for Marine-Science and Technology. In the recent few years, we have measured heat flow in and around the Iheya-North hydrothermal field to understand the spatial of hydrothermal circulation in detail. 78 measurements show that heat flow is higher than 10 W/m2 with in 0.5 km of the hydrothermal vent complex, that it gradually decrease eastward to vs. ~a few hundreds meters vertical). We performed numerical calculations of fluid flow and heat transportation to give constraints on the depth of hydrothermal circulation, the magnitude of darcy velocity, and the permeability at depth. The simulated results will be compared with measured heat flow distribution and will be checked for the larger or smaller circulation scale proposed from heat flow or fluid geochemistry data.

  6. Microthermometric measurement of fluid inclusions and its constraints on genesis of PGE-polymetallic deposits in Lower Cambrian black rock series, southern China

    Institute of Scientific and Technical Information of China (English)

    WANG Min; SUN Xiaoming; MA Mingyang

    2005-01-01

    Systematic microthermometric measurements of fluid inclusions in the PGE-polymetallic deposits hosted in the Lower Cambrian black rock series in southern China were performed, and the results suggest: (1) there exist two types of fluid inclusions. TypeⅠis of NaCl-H2O system with low-medium salinity, and its homogenization temperatures (Th) and salinities are 106.9- 286.4℃ and ( 0.8- 21.8) wt%NaCl eq. respectively; TypeⅡ is of CaCl2-NaCl-H2O system with medium-high salinities, and its homogenization temperatures and salinities range from 120.1℃ to 269.6℃ and ( 11.4- 31.4) wt%NaCl eq., respectively. The typeⅡ fluid inclusions have been discovered for the first time in this kind of deposits; (2) two generations of ore-forming fluids were recognized. Characteristics of fluid inclusions in the PGE-polymetallic ores and carbonate-quartz stockworks in the underlying phosphorites are almost of no difference, they may represent ore-forming fluids at the main metallogenic stage. The peak value of homogenization temperature of those fluid inclusions is about 170℃, while their salinities possess a remarkable bimodal distribution pattern with two peak values of (27-31) wt%NaCl eq. and (4-6) wt%NaCl eq. On the contrary, fluid inclusions in the carbonate-quartz veins in the hanging wall may represent ore-forming fluids at the post-metallogenetic stage. The homogenization temperatures and the peak values of salinities are mostly 130-170℃ and (12-14) wt%NaCl eq., respectively; (3) nobel gas isotopic composition analyses in combination with the microthermometric measurements of fluid inclusions suggest that the ore-forming fluids at the main metallogenetic stage were probably derived from mixing of basinal hot brines with the CaCl2-NaCl-H2O system and seawater with the NaCl-H2O system; (4) in the Early Cambrian, the basinal hot brines were trapped in the Caledonian basins, which were distributed along the southern margin of the Yangtze Craton, and where giant thick

  7. Research on Magnesite Ore Purification

    Directory of Open Access Journals (Sweden)

    Berisha, K.

    2009-12-01

    Full Text Available Magnesite ore, consisting mainly of magnesite, MgCO3 is a chief mineral source for production of high quality refractory materials based on highly pure MgO. However, the presence of calcium and silicium mineral impurities in the ore adversely affect refractoriness. The removal of silicate minerals is now a routine process but it is not so for calcium minerals impurities. In this work, the new method for the removal of calcium mineral impurities from magnesite ore has been investigated. It is based on extraction of calcium hydroxide from the calcined hydrated ore with the solution of magnesium nitrate. The results show that it is possible to remove up to 65–83 % of calcium oxide (CaO within five minutes, and up to 88–95 % within an hour. The process itself is complex, but mainly under mass transfer control. It is possible to use waste materials produced as fertilizer in agriculture thus helping in environmental protection.

  8. Joint inversion of PP and PS AVAZ data to estimate the fluid indicator in HTI medium: a case study in Western Sichuan Basin, China

    Science.gov (United States)

    Pan, Bei; Sen, Mrinal K.; Gu, Hanming

    2016-10-01

    The existence of fractures in an otherwise isotropic medium induces anisotropy in the medium. Because of existing in situ stress, most fractures are often aligned close to vertical, rendering a reservoir azimuthally anisotropic in character. Joint interpretation of PP and PS seismic data generally provides greater details in resolution of the estimated subsurface rock properties and geological structures than conventional PP seismic data. Here we report on the applicability of PP and PS azimuthal amplitude variation with offset (AVAZ) data in fracture characterization. The theory is based on a linear slip model and the Born formula such that PP- and PS-reflection coefficients are sensitive to fracture weaknesses. First we demonstrate numerical experiments with synthetic PP-AVAZ, PS-AVAZ and joint inversion to estimate fluid indicator. Results show that when the fractures have low saturation of gas, the fluid indicator estimated from PP-AVAZ data is fairly accurate. However, when gas saturation reaches up to 70%, joint inversion can help to improve the resulting poor quality in PP-AVAZ data inversion. For high values of gas-saturation, both PP inversion and joint inversion are sensitive to errors in background Poisson’s ratio. Based on the result of our numerical experiment with synthetic data, we analyze a field dataset from the Western Sichuan Basin in China. The inversion result is consistent with well log based interpretation. All known reservoirs are accurately depicted by the estimated fluid indicator while the false gas zones interpreted by other methods are eliminated. When displayed as an inline section, the distribution of reservoirs appears consistent with the interpretation of the stratigraphy and geological structures.

  9. Organic Geochemistry Characteristics in Ores and Host Rocks from Qixiashan Lead-Zinc Deposit, Nanjing, China

    Institute of Scientific and Technical Information of China (English)

    Xie Shucheng; Wang Hongmei; Guo Jianqiu; Liang Bin; Zhou Xiugao

    2003-01-01

    Organic matter, associated with ores, host rocks, ore source rocks and present in fluid inclusions in the Qixiashan lead-zinc polymetallic deposit hosted in Upper Carboniferous dolomites and limestones in East China, was systematically analyzed using Fourier transform infrared spectroscopy, gas chromatography (GC), GC/mass spectrometry and proton-induced X-ray emission. The biomarker ratios of nC-21-/nC+22-alkanes, C23-tricyclic/C30-hopane and the tricyclic terpane parameters including C21/C23, C19-20/C21-29 and C19-25/C26-29 can effectively discriminate ores from host rocks. Extractable organic matter present in fluid inclusions displays similarities to those enclosed in the ore source rocks in the biomarker ratios, suggesting that a proportion of organic matter was introduced into the deposit from the ore source strata. The presence of copper and zinc in stage Ⅱ pyrobitumen indicates that some metals may have been transported by an organic fluid or removed from an aqueous fluid by organic matter.

  10. 四川省牦牛坪稀土矿床成矿流体与碳酸岩-正长岩杂岩体成因联系评述%Genetic Relation of Ore-Forming Fluids and Carbonatite- Syenite Complex in Maoniuping REE Deposit, Sichuan Province, China:A Review

    Institute of Scientific and Technical Information of China (English)

    许成; 黄智龙; 漆亮

    2004-01-01

    The Maoniuping REE deposit is the second largest primary light REE deposit in China.Fluorite is one of main gangue minerals in the orefield. Carbonatites and syenites are spatially and temporally associated with rare earth mineralization. Based on the previous geochemical studies of fluorite and carbonatite-syenite complex, we review the genetic relation of REE ore-forming fluids and carbonatite-syenite complex. It shows that carbonatites and syenites have similar REE distribution patterns, (87Sr/86Sr)0, (143Nd/144Nd)0, 206Pb/204Pb, 208Pb/204Pb ratios, and plot to the area between the mantle end-member EM1 and EM2. They were formed in orogenic setting. Fluorites associated with REE mineralization display different REE distribution patterns, but their Sr, Nd, Pb isotopic ratios are uniform, and are similar to those of carbonatites and syenites. This suggests that the different REE fluorites were products of the same source, and REE ore-forming fluids were related to carbonatite and syenite magmas.%四川省牦牛坪稀土矿床是中国第二大原生轻稀土矿床,萤石是矿区主要脉石矿物之一,碳酸岩和正长岩在空间和时间上与稀土成矿存在密切联系.在过去萤石和碳酸岩-正长岩杂岩体地球化学研究的基础上,评述了稀土成矿流体与碳酸岩-正长岩杂岩体的成因联系.矿区碳酸岩和正长岩具有相似的REE配分模式、(87Sr/86Sr)0,(143Nd/144Nd)0,206Pb/204Pb,208Pb/204Pb同位素比值,位于地幔端元EM1和EM2之间,它们是造山环境的产物.与稀土矿化共生的萤石显示不同的稀土配分模式,但是它们具有一致的Sr、Nd、Pb同位素比值,与碳酸岩和正长岩相似.这些表明不同稀土特征的萤石来自相同的源区,稀土成矿流体与碳酸岩和正长岩岩浆存在密切联系.

  11. Extraction of uranium from its ores

    International Nuclear Information System (INIS)

    The ore is ground and mixed with sulphuric acid to give a moist ore containing a sulphuric acid concentration of less than 4N without forming a continuous liquid phase. The moist ore is cured at from 500 to 1000 while passing an oxidising gas through it. Using this method it is possible to achieve uranium extractions of % or better in 24 hours or less. This invention provides an improved method for acid leaching of uranium from its ores and especially from those ores which contain uranium as a finely-diaseminated refractory material, such as brannerite or uraninite. (LL)

  12. Method of continuous pressure leaching of ores

    International Nuclear Information System (INIS)

    Ore leaching, especially suspensions of ground ore or fine ore fractions from physical treatment was divided into two operations. The former, i.e., ore mixing with technical grade concentrated sulfuric acid proceeded in a separate mixer. The mixture was then transported into an autoclave where the actual leaching proceeded for 2 to 4 hours. The extracted mixture was discharged through the autoclave bottom. The leaching autoclave used can be without any inner structures. The separation of mixing from the actual leaching allows processing ores with high levels of clay components, increasing operating reliability of the facility, reducing consumption of special structural materials and energy, and increasing process efficiency. (E.S.)

  13. Origin of Gold-Bearing Fluid and Its Initiative Localization Mechanism in Xiadian Gold Deposit, Shandong Province

    Institute of Scientific and Technical Information of China (English)

    邓军; 王庆飞; 孙忠实

    2002-01-01

    The composition of quartz inclusions and trace elements in ore indicate that gold bearing fluid in the Xiadian gold deposit, Shandong Province, stemmed from both mantle and magma, belonging to a composite origin. Based on theoretical analysis and high temperature and high pressure experimental studies, gold-bearing fluid initiative localization mechanism and the forming environment of ore-host rocks are discussed in the present paper. The composite fluid extracted gold from rocks because of its expanding and injecting forces and flew through ore-conducive structures, leading to the breakup of rocks. The generation of ore-host faults and the precipitation of gold-bearing fluid occurred almost simultaneously. This study provides further information about the relationships between gold ore veins and basic-ultrabasic vein rocks and intermediate vein rocks, the spatial distribution of gold ore veins and the rules governing the migration of ore fluids.

  14. Fluid-mediated metal transport in subduction zones and its link to arc-related giant ore deposits: Constraints from a sulfide-bearing HP vein in lawsonite eclogite (Tianshan, China)

    Science.gov (United States)

    Li, Ji-Lei; Gao, Jun; John, Timm; Klemd, Reiner; Su, Wen

    2013-11-01

    High-pressure (HP) veins in eclogites provide insight into element mobility during fluid-rock interaction in subduction zones. Here, we present a petrological-geochemical study of a sulfide-bearing HP vein and its massive lawsonite eclogite host rock from the Chinese Tianshan (ultra-)high-pressure/low-temperature metamorphic belt. The omphacite-dominated vein is enveloped by a garnet-poor, sulfide-bearing eclogite-facies reaction selvage. Lawsonite, garnet, omphacite, glaucophane and other HP minerals occur as inclusions in pyrite porphyroblasts of the selvage rock, indicating that the selvage formed prograde under eclogite-facies conditions. Relicts of wall-rock garnet (Grt_I) cores in recrystallized selvage garnet (Grt_II) close to the wall rock and the Ca distribution in Grt_II, which images the overgrown selvage matrix, indicate that the selvage formed due to dissolution-precipitation processes as a consequence of fluid-rock interaction of the wall rock eclogite with the vein-forming fluid. The peak metamorphic P-T conditions of the wall-rock eclogite are estimated at ca. 590 °C and 23 kbar. Mass-balance calculations indicate that the reaction selvage experienced: (1) a depletion of the large-ion lithophile elements (K-Rb-Ba) of up to 100% relative to their concentrations in the wall-rock eclogite; (2) a moderate depletion of the HREE and some transition metal elements including Fe, Cu, Ni, Zn, Co, Cr, and Mn (10-40%); (3) a significant enrichment of CaO (up to 50-80%), Sr (up to ˜200%), Pb (up to ˜170%) and S (up to ˜210%); (4) a slight to moderate enrichment of the LREE (10-20%) and MREE (0-40%); whereas (5) the HFSE show no significant variations.

  15. Numerical models of carbonate hosted gold mineralization, Great Basin Nevada

    Science.gov (United States)

    Person, M.; Hofstra, A.; Gao, Y.; Sweetkind, D.; Banerjee, A.

    2006-12-01

    The Great Basin, Nevada contains many modern hydrothermal system and world class gold deposits hosted within Paleozoic carbonate rocks. Temperature profiles, fluid inclusion studies, and isotopic evidence suggest that modern geothermal and fossil hydrothermal systems associated with gold mineralization share many common features including the absence of a clear magmatic source, flow restricted to fault zones, and remarkably high temperatures at shallow depth. While the plumbing of these systems is not well understood, geochemical and isotopic data suggest that fluid circulation along fault zones is relatively deep (greater than 5 km) and comprised of relatively unexchanged Pleistocene meteoric water with small (less than 2.5 per mill) shifts from the MWL. Many fossil ore-forming systems were also dominated by meteoric water, but are usually exhibit shifts of 5 to 15 per mill from the MWL. Here we present two-dimensional numerical models to reconstruct the plumbing of modern geothermal and Tertiary hydrothermal systems in the Great Basin. Multiple tracers are used in our models, including O- and C-isotopic compositions of fluids/rocks, silica transport/ precipitation, and temperature anomalies, to constrain the plumbing of these systems. Our results suggest that both fossil hydrothermal and modern geothermal systems were probably driven by natural convection cells associated with localized high basal heating. We conclude that the fault controlled flow systems responsible for the genesis of Carlin gold mineralization and modern geothermal systems had to be transient in nature. Permeability changes within the carbonate reservoir was probably associated with extensional tectonic events.

  16. 滇西北红山铜矿床成矿流体地球化学特征及矿床成因%Geochemical characteristics of ore-forming fluids and genesis of Hongshan copper deposit in northwestern Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    李文昌; 王可勇; 尹光侯; 秦丹鹤; 余海军; 薛顺荣; 万多

    2013-01-01

    The Hongshan copper deposit is a large porphyry-skarn type polymetallic deposit in northwestern Yunnan Province. It occurred in quartz diorite porphyry of Indo-Chinese Period and quartz monzonite porphyry of Yanshanian Period as well as their neighbouring wall rocks. The formation of it experienced superimposition of mutiphases/stages hydrothermal mineralization. Comprehensive study on petrography, microthermometry and carbon-hydrogen-oxygen isotope of fluid inclusions showed that the ore-forming fluids of early metallogenic stages are of medium to high temperature, high salinity NaCl-H2 O type solutions and mainly came from arc magmatism of Indo-Chinese Period, they were responsible for the formation of skarn type mineralization. The ore-forming fluids of later metallogenic stages are of medium to high temperature, high salinity NaCl-CO2 -H2 O type solutions and mainly came from the buried granitic magmatism of post orogenic extension environment, and they played important role in the formation of porphyry type Cu, Mo and relevant Pb, Zn mineralization. So the Hongshan copper deposit is of superimposed poyphyry-skarn type deposit that originated from the metallogenic superimposition of two phases of magmatic hydrothermal fluids.%红山铜矿床为滇西北地区一大型斑岩-矽卡岩型铜多金属矿床,它产于印支期石英闪长玢岩及燕山期石英二长斑岩体内及其周边地层中,其形成经历了多期次热液叠加成矿作用过程.流体包裹体岩相学、显微测温及碳、氢、氧稳定同位素综合研究表明,矿区早期成矿流体为中高温、高盐度NaCl-H2O体系热液,主要来源于印支晚期岛弧型岩浆活动,对区内矽卡岩型矿化形成起了重要作用;晚期成矿流体为中高温、高盐度NaCl-CO2-H2O体系热液,主要来源于隐伏的燕山期后造山伸展型花岗质岩浆侵入体,形成了区内斑岩型Cu、Mo及相关的Pb、Zn多金属矿化.因此,红山铜矿床是

  17. An evaluation of the dissolution process of natural uranium ore as an analogue of nuclear fuel

    International Nuclear Information System (INIS)

    The assumption of congruent dissolution of uraninite as a mechanism for the dissolution behaviour of spent fuel was critically examined with regard to the fate of toxic radionuclides. The fission and daughter products of uranium are typically present in spent unreprocessed fuel rods in trace abundances. The principles of trace element geochemistry were applied in assessing the behaviour of these radionuclides during fluid/solid interactions. It is shown that the behaviour of radionuclides in trace abundances that reside in the crystal structure can be better predicted from the ionic properties of these nuclides rather than from assuming that they are controlled by the dissolution of uraninite. Geochemical evidence from natural uranium ore deposits (Athabasca Basin, Northern Territories of Australia, Oklo) suggests that in most cases the toxic radionuclides are released from uraninite in amounts that are independent of the solution behaviour of uranium oxide. Only those elements that have ionic and thus chemical properties similar to U4+, such as plutonium, americium, cadmium, neptunium and thorium can be satisfactorily modelled by the solution properties of uranium dioxide and then only if the environment is reducing. (84 refs., 7 tabs.)

  18. The source of ore-forming fluids in the Bolong copper mine area, Tibet%西藏波龙铜矿区成矿流体来源示踪

    Institute of Scientific and Technical Information of China (English)

    周玉; 多吉; 温春齐; 费光春; 何阳阳

    2015-01-01

    波龙铜矿床是西藏地质五队近年来在青藏高原中部发现的最大的斑岩型矿床。为了查明波龙铜矿区成矿流体来源,对采自矿区的黄铁矿及石英流体包裹体样品进行了 He、Ar同位素与气相成分测试。测试结果显示黄铁矿流体包裹体3 He/4 He分别为3.03和8.51,40 Ar/36 Ar为214.94和284.23,表明成矿流体可能来源于壳幔混源;石英包裹体气相成分以H2 O为主,次为CO2,还有少量的N2、C H4、C2 H6、H2 S及A r气体,部分样品中还含有O2成分,表明成矿流体中混有高氧逸度组分;结合矿区石英包裹体H‐O同位素显示成矿流体以岩浆源为主、并混有大气成分分析,波龙铜矿区成矿流体应属壳幔混源,早期成矿流体以深源为主,晚期随着流体的演化有部分大气降水的加入。具高氧逸度特征的怒江洋壳俯冲板片携带大量成矿物质俯冲进入羌塘‐三江复合板片南缘深部,熔融交代上覆地幔楔,发生壳幔混合,形成初始岩浆,在上升过程中混染下地壳物质,并受到深循环大气降水的影响最终侵位到上部地壳形成波龙铜矿床。%The Bolong porphyry copper deposit was founded the largest copper deposits in central Tibet Plateau in recent years by No .5 Geological Party ,Tibet Bureau of Geology and Mineral Exploration and Development .In order to identify Source of Ore‐Forming Fluids in the Bolong copper mine and samples of fluid inclusions in pyrite and quartz form Copper Mine Area were Sampled to test their noble gas isotope or gas composition .Testing has shown that 3 He/4 He were 3 .03 and 8 .51 ,and 40 Ar/36 Ar were 214 .94 and 284 .23 ,it showed that ore‐forming fluid may be come from the crust‐mantle mixed source .Gaseous composition of fluid inclusion mainly composed of H 2 O ,followed by CO2 ,in addition to a small amount of N2 ,CH4 ,C2 H6 ,H2 S and Ar ,Portion of the sample composition also contains

  19. Faults-fluids filling rules and ore deposited space selection take Xiaoqinling Gold Deposit for example%断裂-流体充填律与储矿空间选优--以小秦岭金矿带为例

    Institute of Scientific and Technical Information of China (English)

    王美娟; 陈祥; 关连绪

    2014-01-01

    Based on further study ,the faults-fluids filling rules of auriferous fluids divided into three .The frist rule consists filling sequence of fluids in the flat undulate fault ( Fb ) that is from free space to screen space; the second rule:the second sequence is from center wave to nearly similar wave of a single F b;the third law:the third sequence is from major Fb to the nth or the nth side Fb of a Fb group.Based on the filling rule,the selection method for the filling space of endogenous vein type deposits was determined ,including for fault zone(groups) or vein zone(groups),for a Fb(vein) group and many Fb(vein) groups,for wave selection in a single Fb(vein),for wave band selection in the same wave and for the seceond section .The select method for prospecting takes less time ,strength and money than tra-ditional methods .Take Xiaoqinling gold deposit for an example ,the sub-mine zone ,vein group ,vein and center wave are selected.%断裂-流体充填律是在含金流体充填定律基础上,进一步深入研究,升华为3个充填规律:流体在舒缓波状断层( Fb )中充填顺序,由自由空间→屏蔽空间,为第一个充填规律;到1条Fb的中心波→近相似波,为第二个充填规律;再到1组Fb的主Fb→第n对或第n个侧翼Fb ,为第三个充填规律。根据充填律研究出内生脉型矿床空间的选优方法,包括断裂带(群)或矿脉带(群)选优,1组、多组Fb (矿脉)选优;1条Fb (矿脉)的波形选优和同一波形中的波段选优及第二轮选优。选优法找矿比传统法省时、省工、省钱。以小秦岭金矿带为例选优出次级矿带、矿脉组、矿脉和中心波。

  20. Helium isotopic compositions in fluid inclusions of the Gangxi fault belt in the Huanghua Depression, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    DING Weiwei; DAI Jinxing; YANG Chiyin; TAO Shizhen; HOU Lu

    2005-01-01

    The authors obtained 30 core samples from 15 wells in Gangxi fault belt, Huanghua Depression. Using a VG5400 mass spectrometer, the helium isotopic compositions in fluid inclusion of these samples were analysed. Interpretation of results suggests a significant amount of mantle-derived helium in the inclusions, which were likely trapped during Neocene. Mantle-derived helium have mostly accumulated in the intersections of the NWW trending Xuzhuangzi and NE trending Gangxi faults, and decreased away from the intersections. This pattern implied a close relationship to the local tectonic setting. Gangxi fault belt experienced intensive neo-tectonic activities in the Cenozoic. Widespread faulted-depressions and strong volcanic eruptions manifested its tectonic status of extensional stress field. Mantle uplift caused the movement of magma that carried mantle-derived gas, and the deep-rooted tension faults provided the passages for the gases to shallow crust levels. High-content abiogenic CO2 pools occurred in the study area, hence, using the helium isotopic compositions is of great significance to the exploration of abiogenic natural gases.

  1. Discovery and Significance of High CH4 Primary Fluid Inclusions in Reservoir Volcanic Rocks of the Songliao Basin, NE China

    Institute of Scientific and Technical Information of China (English)

    WANG Pujun; HOU Qijun; WANG Keyong; CHEN Shumin; CHENG Rihui; LIU Wanzhu; LI Quanlin

    2007-01-01

    Comparing compositions of the fluid inclusions in volcanic rocks to the contents and isotopes of the gases in corresponding volcanic reservoirs using microthermometry, Raman microspectroscopy and mass spectrum analysis, we found that: (1) up to 82 mole% methane exists in the primary inclusions hosted in the reservoir volcanic rocks; (2) high CH4 inclusions recognized in the volcanic rocks correspond to CH4-bearing CO2 reservoirs that are rich in helium and with a high 3He/4He ratio and which show reversed order of δ13C in alkane; (3) in gas reservoirs of such abiotic methane (>80%)and a mix of CH4 and CO2, the enclosed content of CH4 in the volcanic inclusions is usually below 42mole%, and the reversed order of δ13C in alkane is sometimes irregular in the corresponding gas pools;(4) a glassy inclusion with a homogeneous temperature over 900℃ also contains a small portion of CH4although predominantly CO2. This affinity between gas pool and content of inclusion in the same volcanic reservoirs demonstrates that magma-originated gases, both CH4 and CO2, have contributed significantly to the corresponding gas pools and that the assumed hydrocarbon budget of the bulk earth might be much larger than conventionally supposed.

  2. Processing of low grade uranium ores

    International Nuclear Information System (INIS)

    Four types of low-grade ores are studied: (1) Low-grade ores that must be extracted because they are enclosed in a normal-grade deposit. Heap leaching is the processing method which is largely used. (2) Normal-grade ores contained in low-amplitude deposits. They can be processed using in-place leaching as far as the operation does not need any large and expensive equipment. (3) Medium-grade ores in medium-amplitude deposits. A simplified conventional process can be applied using fast heap leaching. (4) Low-grade ores in large deposits. The report explains processing possibilities leading in most cases to the use of in-place leaching. The operating conditions of this method are laid out, especially the selection of the leaching agents and the preparation of the ore deposit

  3. Measurement of moisture in mill feed ore

    Energy Technology Data Exchange (ETDEWEB)

    Timm, A.R.; Moench, P.; Moisel, E. (Council for Mineral Technology, Randburg (South Africa))

    1985-04-01

    The control of the moisture in the feed to a mill is very important for efficient mill operation. Water is added continuously to the ore fed to a mill to maintain a suitable mix of ore and moisture in the mill. However, problems arise because of the large variation in the moisture content of the ore, which affects the efficiency of the grind. If too little moisture is present, the mill is unable to grind the ore finely enough, creating instead a thick 'porridge' that causes the mill to choke up. On the other hand, too much moisture results in inefficient grinding because the ore is flushed through the mill too quickly. Several techniques are available for measuring moisture and Mintek undertook an investigation in an attempt to develop a reliable robust moisture meter suitable for monitoring the moisture content of ore, which include the following: neutron backscattering, infrared absorption, microwaves, capacitance and moisture as a function of conductivity.

  4. Sintering Characteristics of Indian Chrome Ore Fines

    Science.gov (United States)

    Nandy, Bikash; Chaudhury, Manoj Kumar; Paul, Jagannath; Bhattacharjee, D.

    2009-10-01

    Chrome ore concentrate consists of high-temperature melting oxides such as Cr2O3, MgO, and Al2O3. The presence of these refractory constituents makes the ore a very high melting mineral. Hence, it is difficult to produce sinter from chrome ore by a pyrometallurgical route. Currently, chrome ore is ground to below 75 μm, pelletized, heat hardened through carbothermic reaction at 1300 °C to 1400 °C, and then charged into a submerged electric arc furnace (EAF), along with lumpy ore for ferrochrome/charge-chrome production. Electricity is a major cost element in this extraction process. This work explores the sinterability of chrome ore. The objective of this study was to: (1) determine whether chrome ore is sinterable and, if so, (2) ascertain ways of achieving satisfactory properties at a low temperature of sintering. Sintering of the raw material feed could be a way to reduce electricity consumption, because during sintering a partial reduction of minerals is expected along with agglomeration. Studies carried out by the authors show that it is possible to agglomerate chrome ore fines through sintering. The chrome ore sinter thus produced was found to be inferior in strength, comparable to that of an iron ore sinter, but strength requirements may not be the same for both. Because the heat generation during chrome ore sintering is high owing to some exothermic reactions, compared with iron ore, and because chrome ore contains a high amount of fines, shallow-bed-depth sinter cake production was attempted in the laboratory-scale pot-sintering machine. The sintered product was found to be a good conductor of electricity because of the presence of phases such as magnetite and maghemite. This characteristic of the chrome ore sinter will subsequently have a favorable impact in terms of power consumption during the production of ferrochrome in a submerged EAF. The sinter made was melted in the arc furnace and it was found that the specific melting energy is comparable to

  5. Mineralogy and geochemistry of banded iron formation and iron ores from eastern India with implications on their genesis

    Indian Academy of Sciences (India)

    Subrata Roy; A S Venkatesh

    2009-12-01

    The geological complexities of banded iron formation (BIF) and associated iron ores of Jilling–Langalata iron ore deposits, Singhbhum–North Orissa Craton, belonging to Iron Ore Group (IOG) eastern India have been studied in detail along with the geochemical evaluation of different iron ores. The geochemical and mineralogical characterization suggests that the massive, hard laminated, soft laminated ore and blue dust had a genetic lineage from BIFs aided with certain input from hydrothermal activity. The PAAS normalized REE pattern of Jilling BIF striking positive Eu anomaly, resembling those of modern hydrothermal solutions from mid-oceanic ridge (MOR). Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The ubiquitous presence of intercalated tuffaceous shales indicates the volcanic signature in BIF. Mineralogical studies reveal that magnetite was the principal iron oxide mineral, whose depositional history is preserved in BHJ, where it remains in the form of martite and the platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Removal of silica from BIF and successive precipitation of iron by hydrothermal fluids of possible meteoric origin resulted in the formation of martite-goethite ore. The hard laminated ore has been formed in the second phase of supergene processes, where the deep burial upgrades the hydrous iron oxides to hematite. The massive ore is syngenetic in origin with BHJ. Soft laminated ores and biscuity ores were formed where further precipitation of iron was partial or absent.

  6. 内蒙古达茂旗哈力齐金矿床地质和流体包裹体特征及成因类型%Characteristics of ore geology and fluid inclusion of the Haliqi gold deposit, Damao County,Inner Mongolia,and its metallogenic type

    Institute of Scientific and Technical Information of China (English)

    吴兆剑; 韩效忠; 祁才吉; 郑宇舟; 王明太; 郑云龙

    2013-01-01

    With a 3-year investigation,the Haliqi gold deposit in Inner Mongolia ,a quartz vein type gold deposit, was recently found in Damao Banner ,Inner Mongolia.It is controlled by a fault north Wude magmatic tectonic melange belt and hosted in the Lower Devonian Chaganhebu group epimetamorphic rocks .Mineralization types include quartz vein type and mylonitic alteration type.The ore-forming minerals mainly consist of quartz ,sericite,pyrite,limonite, hematite,arsenopyrite and native gold.Ores mainly take form of vein structure and are occasionally in the form of miar-olitic structure.Textures of ores are metasomatic corona textures ,metasomatic harbor-like textures,limonite relict tex-tures and zonal textures.The wall-rock alterations are dominated by silicification,sericitization,and argillation.The hy-drothermal ore-forming process includes three stages,namely the early stage characterized by pyrite-bearing quartz vein,the main stage characterized by quartz-pyrite-arsenopyrite-native gold process and the late stage characterized by carbonate-quartz veinlets.The study of fluid inclusions in quartz indicates that in the main stage fluid inclusions are dominated by aqueous solution inclusions and pure CO 2 inclusions,with densities of 0.85-0.9 g/cm 3 ,trapping tem-peratures of 190-370 ℃and pressures of 61-183 MPa,and mineralization depth of 6.1-6.9 km.The study indi-cates that Haliqi deposit is a low density and low salinity epithermal gold deposit with features of orogenic type depos -its.%  通过近3年的多金属普查工作,在内蒙古达茂旗哈力齐地区发现了一个石英脉型金矿床。金矿床产于下泥盆统查干合布组浅变质岩中,受乌德岩浆构造混杂带北侧断层控制,矿化类型有石英脉型和糜棱状蚀变岩型两类。矿石的组成矿物主要有石英、绢云母、黄铁矿、褐铁矿、赤铁矿、毒砂、自然金等。矿石构造主要为脉状构造,偶见晶洞构造;矿石结构为

  7. BIOREMEDIATION OF LOW GRADE ORES

    OpenAIRE

    Rashmi Mishra*

    2016-01-01

    The research work presented in this paper is on a Bioremediation for the recovery of zinc from mining waste i.e. Low grade ore of Hindustan Zinc Limited. They are waste product for the mines, as the recovery process is expensive compared to the recovery product moreover it causes lots of pollution   Bioleaching Studies were carried out at different pH using mixed culture grown from mine water. Recovery of zinc in control set (without culture) was 8% in 37 days and at the same pH ...

  8. Temporal and spatial distribution of Au-Ag polymetallic ore deposits and source of ore-forming materials in the Zhangjiakou-Xuanhua mantle-branch metallogenetic zone

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Zhangjiakou-Xuanhua area is a mineral resource-concentrated area for gold-silver polymetallic ore deposits. The temporal and spatial distribution and origin of mineral resources have been argued for a long time. Based on the comprehensive studies of geochronology and sulfur, lead, oxygen, carbon and noble gas isotopes, it is considered that the temporal and spatial distribution of mineral resources in this area is obviously controlled by the Zhangjiakou-Xuanhua mantle branch structure, as is reflected by the occurrence of gold deposits in the inner parts and of Ag-Pb-Zn polymetallic ore deposits in the outer parts. The mineralization took place mainly during the Yanshanian period. Ore-forming materials came largely from the deep interior of the Earth, and hydrothermal fluids were derived predominantly from Yanshanian magmatism.

  9. The uranium ore deposits in Ciudad Rodrigo Phyllites. about the possibility of new deposits; Los yacimientos uraniferos en las pizarras paleozoicas de Ciudad Rodrigo. sobre la posible existencia de nuevas mineralizaciones

    Energy Technology Data Exchange (ETDEWEB)

    Mingarro Martin, E.; Marin Benavente, C.

    1969-07-01

    The main features of the genesis of uranium deposits of the Fe mine type, are discussed in this paper. Pitchblende ore is related with phyllites bearing organic material and with geomorphological level, fossilized by eocene sediments. As a result, new uranium ore deposits are possible under Ciudad Rodrigo tertiary basin, tertiary cover depth being little more than three hundred feet. (Author)

  10. Fault Networks in the Northwestern Albuquerque Basin and Their Potential Role in Controlling Mantle CO2 Degassing and Fluid Migration from the Valles Caldera

    Science.gov (United States)

    Smith, J. R.; Crossey, L. J.; Karlstrom, K. E.; Fischer, T. P.; Lee, H.; McGibbon, C. J.

    2015-12-01

    The Rio Grande rift (RGR) has Quaternary and active volcanism and faulting that provide a field laboratory for examining links between mantle degassing and faults as fluid conduits. Diffuse and spring CO2 flux measurements were taken at 6 sites in the northwestern Albuquerque Basin (NWAB) and Valles caldera geothermal system. All sites progress to the southwest from the 1.25 Ma Valles caldera, down the rift-related Jemez fault network, to intersect with the Nacimiento fault system. Mantle CO2 and He degassing are well documented at 5 of 6 sites, with decreasing 3He/4He ratios away from the caldera. The instrument used to measure CO2 flux was an EGM-4 CO2 gas analyzer (PP systems) with an accumulation chamber. Carbonic springs at Penasco Springs (PS) and San Ysidro (SY), and the carbonate-cemented Sand Hill Fault (SHF) were targeted, all near the western border of the RGR. The SHF has no spring activity, had the smallest maximum flux of all the sites (8 g/m2d), but carbonate along the fault zone (network. The maximum diffuse flux recorded at SY (297 g/m2d) and PS (25 g/m2d) are high, especially along the fault and near springs. At SY and PS the instruments capacity was exceeded (2,400 g/m2d) at 6 of 9 springs. Interpretations indicate a direct CO2 flux through a fault-related artesian aquifer system that is connected to magmatic gases from the caldera. Maximum diffuse flux measurements of Alamo Canyon (20,906 g/m2d), Sulphur Springs (2,400 g/m2d) and Soda Dam (1,882 g/m2d) at Valles caldera geothermal sites are comparable to Yellowstone geothermal systems. We use geospatial analysis and local geologic mapping to examine relationships of CO2 flux to structure. Travertine mounds can create impermeable barriers that modify near-surface degassing patterns, making it difficult to decipher where CO2 and fluids preferentially migrate up the damage zones in the hanging-wall or footwall. Future work will utilize grids to more accurately assess the localized affect fault

  11. Estimating gold-ore mineralization potential within Topolninsk ore field (Gorny Altai)

    Science.gov (United States)

    Timkin, T.; Voroshilov, V.; Askanakova, O.; Cherkasova, T.; Chernyshov, A.; Korotchenko, T.

    2015-11-01

    Based on the results of ore and near-ore metasomatite composition analysis, the factors and indicators of gold-ore mineralization potential were proposed. Integration of the obtained data made it possible to outline magmatic, structural, and lithological factors, as well as direct and indirect indicators of gold-ore mineralization. Applying multidimensional analysis inherent to geochemical data, the spatial structure was investigated, as well as the potential mineralization was identified. Based on the developed and newly-identified mineralization, small (up to medium-sized) mineable gold-ore deposits in skarns characterized by complex geological setting was identified.

  12. Effects of non-aqueous fluids-associated drill cuttings discharge on shelf break macrobenthic communities in the Campos Basin, Brazil.

    Science.gov (United States)

    Santos, Maria Fernanda L; Silva, Janete; Fachel, Jandyra M G; Pulgati, Fernando H

    2010-08-01

    This paper assesses the effects of non-aqueous fluids (NAF)-associated drill cuttings discharge on shelf break macrobenthic communities in the Campos Basin, off the southeast Brazilian coast, Rio de Janeiro State. Samples were taken with a 0.25-m2 box corer from surrounding two oil and gas wells on three monitoring cruises: before drilling, three months after drilling, and 22 months after drilling. Statistical methodologies used Bayesian geostatistical and analysis of variance models to evaluate the effects of the NAF-associated drill cuttings discharge and to define the impact area. The results indicated that marked variations were not observed in the number of families between cruises, though there were changes in the fauna composition. The changes seen in biological descriptors in both control and background situation areas were not considered significant, showing a temporal homogeneity in means. The impact area presented changes in biological descriptors of communities and trophic structure during the three cruises and such changes were correlated to chemical and physical variables related to the drilling activities, as a result of the mix of drill cuttings and sediment and the anoxic conditions established in the substrate. In that area, three months after drilling, a decrease in diversity and an increase in density, motile deposit-feeders and Pol/Crp ratio, and dominance of opportunistic organisms, such as the capitellid Capitella sp., were observed and, 22 months after drilling, an increase of diversity, reduction of dominance of capitellid polychaete, changes in the fauna composition, and a dominance of opportunistic burrowing and tube-building organisms were observed, indicating an ecological succession process. PMID:20524059

  13. Fuzzy Comprehensive Appraisal of Concealed Ore Deposits

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the transformation from the fuzzy to the accurate process is exemplified by the Jiaodong gold ore deposits concentrated region where the mathematical analysis is used to appraise and forecast regional concealed gold ore deposits. In this sense, this paper presents a new way to the appraisal of the non-traditional mineral resources.

  14. Iron from Zealandic bog iron ore -

    DEFF Research Database (Denmark)

    Lyngstrøm, Henriette Syrach

    2011-01-01

    og geologiske materiale, metallurgiske analyser og eksperimentel arkæologiske forsøg - konturerne af en jernproduktion med udgangspunkt i den sjællandske myremalm. The frequent application by archaeologists of Werner Christensen’s distribution map for the occurrence of bog iron ore in Denmark (1966...... are sketched of iron production based on bog iron ore from Zealand....

  15. The Luster of Iron Ore Prices

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China battles its way out of an iron ore stalemate by finding alternative supplier After months of seesawing, China’s iron ore negotiators appear to be breaking through the tight encirclement of suppliers. On August 17, the China Iron and Steel Association (CISA) announced that Fortescue

  16. Geochemical Characteristics of Two Types of Ores from Jinshan Shear Zone—hosted Gold Deposit,Jiangxi,with a Discussion on the Mechanism of Two—stage Mineralization

    Institute of Scientific and Technical Information of China (English)

    季峻峰; 刘英俊; 等

    1995-01-01

    Two types of gold ores,siliceous mylonite and quartz vein,formed at the first and second stages of mineralization respectively, can be clearly recognized in the shear zone-hosted gold deposit at Jinshan, Jiangxi.Similarity in REE and trace elements between the siliceous mylonite and the country rocks indicates that the ore metals were supplied by the surrounding strata during the first stage of mineralization.On the other hand, as indicated by fluid inclusion data,the ore-forming fluid at the second stage was of meteoric origin and the precipitation of gold was caused by phase separation.

  17. A Study on the Geological—Geochemical Dynamics of Hydrothermal Ore Deposition as Exemplified by the Muping—Rushan Gold Deposit Belt,Eastern Shandong,China

    Institute of Scientific and Technical Information of China (English)

    赵伦山; 高太忠; 等

    1996-01-01

    This paper presents a method of establishing a hydrothermal ore-forming reaction system.On the basis of the study of four typical hydrothermal deposits,the following conclusions concerning geochemical dynamic controlling during hydrothermal mineralization have been sions concerning geochemical dynaamic controlling during hydrothermal mineralization have been drawn:(1)The regional tectonic activities control the concentration and dispersion of elements in the ore-forming process in terms of their effects on the thermodynamic nature and conditions of the ore-forming reaction system.(2)During hydrothermal mineralization the activites of ore-bearing faults can be divideb into two stages:the brittle splitting stage and the brittle-tough tensing stage,which would create characteristically different geodynamic conditions for the geochemical thermodynamic ore-forming system.(3)The hydrothermal ore-forming reaaction system is an open dynamic system.At the brittle splitting stage the system was so strongly supersaturated and unequilibrated as to speed up and enhance the crystallization and differentiation of ore-forming fluids.And at the brittle-tough tensing stage,the ore-forming system was in a weak supersaturated state;with decreasing temperature and pressure the crystallization of oreforming material would show down,and it can be regarded as an equilibrated state.(4)In the lates stages of hydrothermal evolution,gold would be concentrated in the residual ore-forming solution.The pulsating fracture activite in this stage led to the crush of pyrite ore and it was then filled with gold-enriched solution,forming high-grage“fissure”gold ore.This ore-forming process could be called the coupling mechanism of ore formation.

  18. Sulfur isotope evidence for penetration of MVT fluids into igneous basement rocks, southeast Missouri, USA

    Science.gov (United States)

    Shelton, K. L.; Burstein, I. B.; Hagni, R. D.; Vierrether, C. B.; Grant, S. K.; Hennigh, Q. T.; Bradley, M. F.; Brandom, R. T.

    1995-08-01

    Previous studies of galena and sphalerite from Paleozoic MVT deposits in the Viburnum Trend, southeast Missouri documented large variations in δ34S values throughout the ore-forming event. The present study of Cu-Fe-sulfides reveals a similar δ34S variation that reflects two end-member sulfur reservoirs whose relative importance varied both temporally and spatially. More 34S-enriched sulfides (δ34S approaching 25‰) indicate introduction of sulfur from basinal sedimentary sources, whereas more 32S-enriched sulfides (δ34S Precambrian, igneous-hosted FeCu mineralization in southeast Missouri (West and Central Domes of Boss-Bixby) were investigated to elucidate their relationship to Cu-rich MVT orebodies hosted nearby within the overlying Cambrian Bonneterre Dolomite. Mineralization at Boss-Bixby is composed of an early phase of iron oxide deposition followed by Cu-Fe-sulfides. The Central Dome is faulted and its mineralization is more fracture-controlled than the typically podiform ores of the West Dome. The δ34S values of West Dome sulfides are 0.9 to 6.5‰ and pyrite-chalcopyrite indicate a temperature of 525° ± 50 °C. These data indicate an igneous source of sulfur during Precambrian ore deposition. In contrast, δ34S values of Central Dome sulfides are 9.4 to 20.0‰ and pyrite-chalcopyrite indicate temperatures of 275° ± 50 °C. Similar δ34S values are obtained for chalcopyrite from the overlying MVT deposits. We speculate that deeply circulating, basin-derived MVT fluids mobilized sulfur and copper from the underlying igneous basement and redeposited them in overlying Curich MVT orebodies, as well as overprinting earlier Precambrian sulfides of the Central Dome with a later, Paleozoic MVT sulfur isotope signature. Many models for MVT fluid circulation in the Midcontinent region of North America assume that igneous basement rocks are an impermeable boundary, but in southeast Missouri, evidence exists for structurally controlled MVT fluid movement

  19. 西藏努日铜钼钨矿床辉钼矿微量元素、稀土元素地球化学特征--对矿床成矿流体性质的约束%Geochemical Characteristics of Trace Elements and REE of Molybdenites from the Nuri Cu-Mo-W Deposit,Tibet:Constraint on Nature of the Ore-Forming Fluid

    Institute of Scientific and Technical Information of China (English)

    闫国强; 丁俊; 黄勇; 李光明; 王欣欣; 戴婕; 白景国

    2015-01-01

    为厘清努日铜钼钨矿床的成矿时代,以矿床中的辉钼矿为研究对象,用 ICP-MS 分析方法,开展了稀土元素和微量元素地球化学研究。结果显示,辉钼矿具有典型的轻重稀土分馏、轻稀土元素(LREE)富集的右倾配分模式,辉钼矿稀土元素具有强烈的 Ce 负异常和 Eu 负异常,前者可能为成矿流体本身具有高温高氧逸度导致,后者可能是与矽卡岩矿化有密切关系的黑云母花岗闪长岩浆在分离结晶过程中大量的斜长石晶出引起的,同时岩体蚀变过程中对成矿流体体系亏损铕有一定贡献。辉钼矿中 Pb、Ba、V、Ni、Sr、Rb 含量相对较高,U、Th 含量非常低,Hf/Sm、Th /La 远小于1,Nb /La 远大于1,表明成矿流体早期以富 F 的来自于深部幔源的岩浆热液为主,而Y /Ho、Zr/Hf、Nb /Ta 变化范围存在不同幅度的差异。表明主成矿期成矿流体在该阶段不同程度的混入了部分外来流体而富 Cl,但总体特征仍以早期成矿流体为主。%Geochemical characteristics of rare earth and trace elements in the molybdenite were studied with ICP-MS method to identify the metallogenic epoch of the Nuri Cu-Mo-W Deposit.The results showed that the light and heavy REEs were fractionated obviously,molybdenite was low with negative cerium and europium anomalies that was characterized by enrichment in light REE.The former found ore-forming fluid had the characteristics of high temperature and high oxygen fugacity,and the latterwas caused by plagioclase crystal in the process of biotite monzonitic granite magma separation and crystallization which had close contact with the skarn,meanwhile gain the contribution from the process of rock alteration. The contents of Pb,Ba,V,Ni,Sr and Rb were relatively high but contents of U and Th were very low.The enrichment indexes of LREE,Hf/Sm and Th /La were far less than 1 while that of Nb /La was greater than 1,indicating

  20. Modeling of the fault-controlled hydrothermal ore-forming systems

    International Nuclear Information System (INIS)

    A necessary precondition for the formation of hydrothermal ore deposits is a strong focusing of hydrothermal flow as fluids move from the fluid source to the site of ore deposition. The spatial distribution of hydrothermal deposits favors the concept that such fluid flow focusing is controlled, for the most part, by regional faults which provide a low resistance path for hydrothermal solutions. Results of electric analog simulations, analytical solutions, and computer simulations of the fluid flow, in a fault-controlled single-pass advective system, confirm this concept. The influence of the fluid flow focusing on the heat and mass transfer in a single-pass advective system was investigated for a simplified version of the metamorphic model for the genesis of greenstone-hosted gold deposits. The spatial distribution of ore mineralization, predicted by computer simulation, is in reasonable agreement with geological observations. Computer simulations of the fault-controlled thermoconvective system revealed a complex pattern of mixing hydrothermal solutions in the model, which also simulates the development of the modern hydrothermal systems on the ocean floor. The specific feature of the model considered, is the development under certain conditions of an intra-fault convective cell that operates essentially independently of the large scale circulation. These and other results obtained during the study indicate that modeling of natural fault-controlled hydrothermal systems is instructive for the analysis of transport processes in man-made hydrothermal systems that could develop in geologic high-level nuclear waste repositories

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

    Science.gov (United States)

    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 (modified basinal brines that have reacted and equilibrated with intercalated siliciclastic rocks. Magnesite formation is genetically linked to regional hydrothermal dolomitisation associated with lithospheric delamination, late-Variscan high heat flow and extensional tectonics in the NW Iberian Belt. A comparison with genetic models for the Puebla de Lillo talc deposits suggests that the formation of hydrothermal replacive magnesite at Rubian resulted from a metasomatic column with magnesite forming at higher fluid/rock ratios than dolomite. In this study, magnesite generation took place via the local reaction of hydrothermal dolostone with the same hydrothermal fluids in very high permeability zones at

  2. Iron Ore Talks, A Prolonged Race

    Institute of Scientific and Technical Information of China (English)

    Zang Kejia

    2009-01-01

    @@ At press time,Chinese steel makers and the World's biggest iron ore minersstill did not reach the final agreement upon the iron ore price,past the original deadline June 30.Since Rio Tinto and Japan's Nippon Steel Corp.reached the 33percent price cut,the iron ore negotiation went into the even harder period.The China Iron and Steel Association (CISA)issued the statement several times that they would not accept the 33 percent cut,but adhere to 40 percent,however,with the negotiation approaching to the end,the situation for China becomes more unoptimistic.

  3. Modelling a uranium ore bioleaching process

    International Nuclear Information System (INIS)

    A dynamic simulation model for the bioleaching of uranium ore in a stope leaching process has been developed. The model incorporates design and operating conditions, reaction kinetics enhanced by Thiobacillus ferroxidans present in the leaching solution and transport properties. Model predictions agree well with experimental data with an average deviation of about ± 3%. The model is sensitive to small errors in the estimates of fragment size and ore grade. Because accurate estimates are difficult to obtain a parameter estimation approach was developed to update the value of fragment size and ore grade using on-line plant information

  4. Rare Earth Element Geochemistry on Magmatic Rocks and Gold Deposits in Shizishan Ore-Field of Tongling, China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    REE geochemical characteristics of the magmatic rocks and gold deposits in Shizishan ore-field of Tongling were studied. Three types of the magmatic rocks have almost the same chondrite-normalized REE patterns, Eu and Ce anomalous values, and ΣREE, ΣLREE/ΣHREE regular changes, which indicates that their magmas come from the same source and their digenetic mechanism is fractional crystallization. In three gold deposits, the mineral ores and related altered rocks have similar chondrite-normalized REE patterns and sharp Eu positive anomalous values. The REE contents reduced from the magmatic rocks to skarnization or alteration magmatic rocks, skarn type ores, sulphide type ores, wall-rocks limestone or marble. The REE geochemical characteristics of the ores and related rocks show that primary fluids originated from magmatic differentiation in lower pressure of shallow crust, ore-forming hydrothermal solutions gained REE and mineralization elements further from leaching the magmatic rocks, then superimposed and reformed the limestones or marbles and deposited ore-forming material.

  5. Fluids in the Palaeogene Formation of Gaoyou Sag in the Southern Part of North Jiangsu Basin, China: Evidence for Hydrocarbon Migration and Accumulation

    Science.gov (United States)

    LI, M.; Lou, Z.; Zhu, R.; Jin, A.

    2013-12-01

    Gaoyou Sag, lying in the middle of the Dongtai Depression in the North Jiangsu basin, China, has a well developed fault system and is characterised by structurally complicated oil and gas fields. Its oil-water relationship is very complicated. In the present study, we present the distribution of formation water chemistry, crude oil density, formation pressures and fluid potential in the Palaeogene formation of the Gaoyou Sag . The purpose of this article is to: (1) analyse the cause of hydrochemical diversity; (2) identify the flow pattern and evolution; and (3) understand the interplay between the flow of formation water and hydrocarbon migration and accumulation. The results showed that large variances in formation water chemistry occur in different oilfields of the Gaoyou Sag (Figure 1) due to dilution by meteoric water recharge, concentration by membrane filtration and complexity of geological structure. The low salinity (mean values from 8.53 g/L to 9.67 g/L) of the formation water and heavy crude oil density (up to 0.94g/cm3) in the Xuchuang oilfield indicate influence from meteoric water infiltration; the deep depression areas are mainly of connate origin. Geofluids in the Xuchuang, Zhenwu and Yang'an oilfields mainly flow vertically through the Zhenwu and Hanliu faults, while geofluids in the Shanian oilfield mainly migrate laterally through the reservoirs and are adjusted vertically along some cutting faults. Palaeo-hydrodynamic evolution had an affinity with the generation, migration, accumulation and preservation of hydrocarbons. In the depositional stages of the Dainan and Sanduo formations, formation water was expelled outward and upward from lacustrine mudstones of the deep depression into shallow sands of nearby oilfields, driven by compaction and overpressure. Hydrocarbon migrated with formation water and gathered in appropriate traps, forming primary reservoirs. During the Zhenwu and Sanduo movements, there were tectonic uplifts and the strata

  6. Giant Mineral Deposits and Their Geodynamic Setting in the Lanping Basin, Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    XUE Chunji; LIU Shuwen; CHEN Yuchuan; ZENG Rong; ZHAO Shihua

    2004-01-01

    There are giant mineral deposits, including the Jinding Zn-Pb and Baiyangping Ag-Co-Cu, and other important mineral deposits (e.g., Baiyangchang Ag-Cu, Jinman Cu deposits, etc.) in the Lanping Mesozoic-Cenozoic Basin, Yunnan Province, China. The tabular ore-bodies and some veins hosted in terrestrial clastic rocks of the MesozoicCenozoic age and no outcropping of igneous rocks in the giant deposits lead to the proposal of syngenetic origin, but the giant mineral deposits are not stratabound (e.g. MVT, sandstone- and Sedex-type). They formed in a continental red basin with intense crust movement. The mineralization is controlled by structures and lithology and occurs in different strata,and no sedimentary nature and no exhalative sediments are identified in the deposits. The deposits show some relations with organic matter (now asphalt and petroleum) and evaporates (gypsum). The middle-low-temperature (mainly 110℃ to 280℃) mineralization took place at a depth of about 0.9 km to 3.1 km during the early Himalayan (58 to 67 Ma). The salinity of ore-forming fluids is surprisingly low (1.6% to 18.0 wt% (NaCl)eq). Affected by the collision of the Indian and Eurasian plates, the mantle is disturbed under the Lanping Basin. The large-scale mineralization is closely linked with the geodynamics of the crust movement, the mantle and mantle-flux upwelling and igneous activity. Giant mineral deposits and their geodynamic setting are unique in the Lanping Basin.

  7. The solubility of a metallic mineral with other coexisting minerals and the ore-forming processes of metallic sulfides

    Institute of Scientific and Technical Information of China (English)

    CEN; Kuang; (岑况); YU; Chongwen; (於崇文)

    2001-01-01

    Most metallic minerals in ore deposits are sulfides. When a sulfide mineral coexists with rock-forming minerals, its solubility is distinctly different from itself alone. The change in dissolution character of a mineral with coexisting rock-forming minerals leads to particular geochemical be-havior. The concept of solubility of a metallic mineral with coexisting rock-forming minerals and its theory and model of calculation are put forward. Taking Tianmashan Cu-Au ore deposit of sulfide minerals in Tongling district as an example, solubilities of some metallic minerals with other coex-isting minerals, such as pyrite or chalcopyrite with quartz (representing sandstone) or calcite (rep-resenting limestone), are calculated. The results show the mechanism of ore-forming processes. As the ore-forming fluid flows through sandstone, it dissolves pyrite in the sandstone at first, then transports the iron and sulfur to the interface between sandstone and limestone and eventually precipitates them on the interface.

  8. Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

    Science.gov (United States)

    Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

    1999-01-01

    -ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

  9. Geological Characteristics of Epithermal Ore Concentrated Areas and Epithermal Ore Deposits in China

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore-control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long-time and wide-scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous-bearing and paleo-pool-bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.

  10. Research of Geochemical Associations of Nephelin Ores

    Science.gov (United States)

    Vulf, M.; Simonov, K.; Sazonov, A.

    The instant paper concerns research of distribution petrogenic chemical members in urtit ore body of Kia-Shaltyrsk deposit. Rocks of the deposit are ore for producing alum earth. Actuality of the subject based on outlooks of detection noble metal ore-bearing (Au, Pt, Pd, Rh, Ru) in alkaline rocks of Siberia, including rocks of Kia-Shaltyrsk deposit (Kuznetsk Alatau). The main purpose of analysis of distribution of members is directed to detection of a non-uniformity of distribution of substance and segments enriched with alum earth and noble members. The basic solved problems are following: o Creation regression models of ore body; o Definition of cumulative distribution functions of members in a contour of ore body; o The analysis of the obtained outcomes in geologic terms. For construction regression models the full-scale data was used, which was presented by the results of the spectral and silicate analyses of gold and petrogenic members containing 130 assays arranged in ore body. A non-linear multiparameter model of the ore body based on components of nephelin ore using neural net approach was constructed. For each member the corresponding distribution function is produced. The model is constructed on the following members: Au, Al2O3, SiO2, Fe2O3, CaO, MgO, SO3, R2O ((Na2O+K2O) -1) and losses of burning. The error of model forecasting membersS concentrations was from 0.02 up to 20%. Large errors basically connected with assays located near contact of ore body and ad- jacent strata or with very high concentrations of members; also they can be connected with different genesis of rocks or superposition of other processes. The analysis of concentrations of members and normalised absolute errors of the fore- cast has shown, that all members can be sectioned into two groups: first: Al2O3, SiO2, R2O, Fe2O3 and second: Au, losses of burning, CaO, MgO, SO3. The distribution of 1 gold is tightly connected with calcium and losses of burning and spatially linked with zones

  11. Sea-level changes and hydrothermal sedimentary mineralization of large-superlarge ore deposits among Sinian to Triassic in South China

    Institute of Scientific and Technical Information of China (English)

    CHEN; Duofu(陈多福); CHEN; Xianpei(陈先沛); CHEN; Guangqian(陈光谦)

    2003-01-01

    Among the Sinian to Triassic strata in South China, the stratiform, quasi-stratiform and lenticular metallic deposits in association with hydrothermal sedimentation mainly occur in the four periods: (1) the Sinian Datangpo interglacial period, (2) the early period of Early Cambrian, (3) the late period of Middle Devonian to early period of Late Devonian,and (4) the late period of Early Permian. The four mineralization periods all happened around the maximum flooding period in the third-order seal-level cycle during the ascending stage in the first-order sea-level cycle. The deep seawater layer, starved and non-compensatory basin, low sedimentary rate, and low energy and anoxic environment during the maximum flooding period are very suitable for the formation and preservation of large to superlarge hydrothermal sedimentary deposits. The maximum flooding period also coincided with the intensified regional tectonism, extensive deep magmatism and hydrothermal sedimentation, which provide, for the formation of large to superlarge hydrothermal sedimentary deposits through the rapid accumulation of hydrothermal sediments, the needed dynamics, ore-forming materials and favorable passway for hydrothermal fluids to enter the basin.

  12. Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA

    Science.gov (United States)

    Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.

    2008-09-01

    Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with

  13. Contrasting hydrological processes of meteoric water incursion during magmatic-hydrothermal ore deposition: An oxygen isotope study by ion microprobe

    Science.gov (United States)

    Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Bouvier, Anne-Sophie; Baumgartner, Lukas; Heinrich, Christoph A.

    2016-10-01

    Meteoric water convection has long been recognized as an efficient means to cool magmatic intrusions in the Earth's upper crust. This interplay between magmatic and hydrothermal activity thus exerts a primary control on the structure and evolution of volcanic, geothermal and ore-forming systems. Incursion of meteoric water into magmatic-hydrothermal systems has been linked to tin ore deposition in granitic plutons. In contrast, evidence from porphyry copper ore deposits suggests that crystallizing subvolcanic magma bodies are only affected by meteoric water incursion in peripheral zones and during late post-ore stages. We apply high-resolution secondary ion mass spectrometry (SIMS) to analyze oxygen isotope ratios of individual growth zones in vein quartz crystals, imaged by cathodo-luminescence microscopy (SEM-CL). Existing microthermometric information from fluid inclusions enables calculation of the oxygen isotope composition of the fluid from which the quartz precipitated, constraining the relative timing of meteoric water input into these two different settings. Our results confirm that incursion of meteoric water directly contributes to cooling of shallow granitic plutons and plays a key role in concurrent tin mineralization. By contrast, data from two porphyry copper deposits suggest that downward circulating meteoric water is counteracted by up-flowing hot magmatic fluids. Our data show that porphyry copper ore deposition occurs close to a magmatic-meteoric water interface, rather than in a purely magmatic fluid plume, confirming recent hydrological modeling. On a larger scale, the expulsion of magmatic fluids against the meteoric water interface can shield plutons from rapid convective cooling, which may aid the build-up of large magma chambers required for porphyry copper ore formation.

  14. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  15. Magmatic Conduit Metallogenic System - A New Model for the Origin of Ore-deposits

    Science.gov (United States)

    Su, S.; Tang, Z.; Wu, G.; Deng, J.; Xiao, Q.; Luo, Z.; Cui, Y.

    2013-12-01

    Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral

  16. The regional distribution regularities of ore-hosting horizon, deposit type and mineralization age of China's sandstone-hosted uranium deposits

    International Nuclear Information System (INIS)

    The sandstone-hosted uranium deposits widespread in China's Meso-Cenozoic sedimentary basins are obviously different from each other in ore-hosting horizon, deposit type (ore-forming process) and in the spatial distribution of mineralization ages. All the above changes are originated from the specific characteristics of the tectonic evolution of each tectonic domain where the deposits occur, obeying the affect resulting from the collision of Indian plate and the subduction of Pacific plate respectively. Basins and sandstone-hosted uranium deposits in the Central domain are effected of both Indian and Pacific plates, and are of characteristics of the two metallogenic systems. (authors)

  17. Geology and D-O-C Isotope Systematics of the Tieluping Silver Deposit,Henan,China:Implications for Ore Genesis

    Institute of Scientific and Technical Information of China (English)

    CHEN Yanjing; Franco PIRAJNO; SUI Yinghui

    2005-01-01

    The Tieluping silver deposit, which is sited along NE-trending faults within the high-grade metamorphic basement of the Xiong'er terrane, is part of an important Mesozoic orogenic-type Ag-Pb and Au belt recently discovered. Ore formation includes three stages: Early (E), Middle (M) and Late (L), which include quartz-pyrite (E),polymetallic sulfides (M) and carbonates (L), respectively. The E-stage fluids are characterized by δD=-90‰,δ13Cco2=2.0‰ and δ18O=9‰ at 373℃, and are deeply sourced; the L-stage fluids, with δD=-70‰,δ13Cco2=-1.3‰ and δ18O=-2‰, are shallow-sourced meteoric water; whereas the M-stage fluids, with δD=-109‰,δ13Cco2=0.1‰ and δ18O=2‰, are a mix of deep-sourced and shallow-sourced fluids. Comparisons of the D-O-C isotopic systematics of the Estage ore-forming fluids with the fluids derived from Mesozoic granites, Archean-Paleoproterozoic metamorphic basement and Paleo-Mesoproterozoic Xiong'er Group, show that these units cannot generate fluids with the measured isotopic composition (high δ18O and δ13C ratios and low δD ratios) characteristic of the ore-forming fluids. This suggests that the E-stage ore-forming fluids originated from metamorphic devolatilization of a carbonate-shale-chert lithological association, locally rich in organic matter, which could correspond to the Meso-Neoproterozoic Guandaokou and Luanchuan Groups, rather than to geologic units in the Xiong'er terrane, the lower crust and the mantle. This supports the view that the rocks of the Guandaokou and Luanchuan Groups south of the Machaoying fault might be the favorable sources. A tectonic model that combines collisional orogeny, metallogeny and hydrothermal fluid flow is proposed to explain the formation of the Tieluping silver deposit. During the Mesozoic collision between the South and North China paleocontinents, a crustal slab containing a lithological association consisting of carbonate-shale-chert, locally rich in organic matter (carbonaceous

  18. Contrasting REE Signatures on Manganese Ores of Iron Ore Group in North Orissa, India

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The distribution pattern of Rare Earth Elements (REE) in three categories of manganese ores viz.stratiform, stratabound-replacement, and detrital of Precambrian Iron Ore Group from north Orissa, India was reported.These categories of Mn-ore differed in their major and trace chemistry and exhibited contrasting REE signature.The stratiform ores were relatively enriched in REE content (697 μg·g-1) and their normalized pattern showed both positive Ce and Eu anomalies, whereas the stratabound-replacement types were comparatively depleted in REE content (211 μg·g-1) and showed negative Ce and flat Eu signatures.The detrital categories showed mixed REE pattern.The data plotted in different discrimination diagrams revealed a mixed volcaniclastic and chemogenic source of material for stratiform categories, and LREE (Light Rare Earth Elements) and HREE (Heavy Rare Earth Elements) are contributed by such sources, respectively.In contrast, the stratabound ore bodies were developed during the remobilization of stratiform ores, and associated Mn-containing rocks under supergene condition followed by the redeposition of circulating mineralized colloidal solutions in structurally favorable zones.During this process, some of the constituents were found only in very low concentration within stratabound ores, and this is attributed to their poor leachability/mobility.The detrital ores did not exhibit any significant characteristic in respect of REE as their development was via a complex combination of processes involving weathering, fragmentation, recementation, and burial under soil cover.

  19. Evidence for deep sea hydrothermal fluid-mineral equilibrium from multiple S isotopes

    Science.gov (United States)

    McDermott, J. M.; Ono, S.; Tivey, M. K.; Seewald, J.

    2010-12-01

    The multiple sulfur isotope systematics of hydrothermal fluids and associated sulfide mineral deposits collected in 2006 in the eastern Manus Basin, Papua New Guinea, provide an opportunity to better understand the processes of mineral precipitation, pore fluid composition, chemosynthetic energy sources, and metal-rich ore deposition in a felsic-hosted back arc hydrothermal system. Recent advances in multiple-stable isotope analytical techniques now enable the precise determination of all four stable isotopes of sulfur in hydrothermal vent fluids and co-precipitated sulfide mineral deposits, which may be used as a tracer to distinguish between sulfide derived from igneous rock, microbial sulfate reduction, and thermochemical reduction of seawater sulfate [1]. Multiple-stable isotopes of sulfur may also help constrain the relative contribution of sulfur derived by degassing of magmatic SO2 and sedimentary sulfide mineral inputs, as either process could generate the isotopically light δ34S (sulfur collected at Manus Basin. We have analyzed the sulfur isotopic composition of high temperature black smoker vent fluid and associated chalcopyrite lining the inner walls of active conduits from two vent fields within the Manus Basin, including PACMANUS, located on the neovolcanic Pual ridge, and vents on discrete volcanic domes at SuSu Knolls. Preliminary results yield vent fluid δ34SH2S values ranging from -4.89 ± 0.02 to 5.41 ± 0.01, which closely match coexisting inner wall δ34Schalcopyrite values, ranging from -4.43 ± 0.01 to 5.64 ± 0.01. These results contrast with previous studies that report systematic differences in vent fluid δ34SH2S and sulfide minerals from the inner conduits of chimney structures [1, 2, 3]. The Δ33SH2S values of vent fluids range from -0.031 ± 0.027 to 0.011 ± 0.016, and those of chalcopyrite range from -0.042 ± 0.012 to 0.012 ± 0.010. Preliminary results in 7 out of 8 fluid-mineral pairs show sulfur isotope exchange at 300-400

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

    Science.gov (United States)

    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

  1. Precipitation of lead-zinc ores in the Mississippi Valley-type deposit at Treves, Cevennes region of southern France

    Science.gov (United States)

    Leach, D.; Macquar, J.-C.; Lagneau, V.; Leventhal, J.; Emsbo, P.; Premo, W.

    2006-01-01

    The Trèves zinc–lead deposit is one of several Mississippi Valley-type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ34S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to −21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur-rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced

  2. 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)

    Science.gov (United States)

    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

  3. Radiometric sorting of Rio Algom uranium ore

    International Nuclear Information System (INIS)

    An ore sample of about 0.2 percent uranium from Quirke Mine was subjected to radiometric sorting by Ore Sorters Limited. Approximately 60 percent of the sample weight fell within the sortable size range: -150 + 25 mm. Rejects of low uranium content (2 (2 counts/in2) but only 7.6 percent of the ore, by weight, was discarded. At 0.8-0.9 counts/cm2 (5-6 counts/in2) a significant amount of rejects was removed (> 25 percent) but the uranium loss was unacceptably high (7.7 percent). Continuation of the testwork to improve the results is proposed by trying to extend the sortable size range and to reduce the amount of fines during crushing

  4. Economic evaluation of preconcentration of uranium ores

    International Nuclear Information System (INIS)

    The economics of two options for the preconcentration of low-grade uranium ores prior to hydrochloric acid leaching were studied. The first option uses flotation followed by wet high-intensity magnetic separation. The second option omits the flotation step. In each case it was assumed that most of the pyrite in the ore would be recovered by froth flotation, dewatered, and roasted to produce sulphuric acid and a calcine suitable for acid leaching. Savings in operating costs from preconcentration are offset by the value of uranium losses. However, a capital saving of approximately 6 million dollars is indicated for each preconcentration option. As a result of the capital saving, preconcentration appears to be economically attractive when combined with hydrochloric acid leaching. There appears to be no economic advantage to preconcentration in combination with sulphuric acid leaching of the ore

  5. Aluminum substitution in goethite in lake ore

    Directory of Open Access Journals (Sweden)

    Carlson, L.

    1995-06-01

    Full Text Available The extent of substitution of Fe by Al in goethite in 32 lake ore samples collected from 11 lakes in Finland varied between 0 and 23 mol-%. The data indicated a negative relationship between Al-substitution and the particle size of lake ore. Differences in the Al-substitution were apparent between sampling sites, suggesting that kinetic and environmental variation in lake ore formation influences the substitution. Non-substituted goethite is formed in coarse-grained sediments with locally high concentrations of Fe due to iron-rich springs. Unit cell edge lengths and volumes of goethite varied as function of Al-subsitution but deviated from the Vegard relationship towards higher values.

  6. A new radiation shielding material: Amethyst ore

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Turgay, E-mail: turgaykorkut@hotmail.co [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Korkut, Hatun [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Karabulut, Abdulhalik; Budak, Goekhan [Faculty of Science, Department of Physics, Atatuerk University, Erzurum (Turkey)

    2011-01-15

    This paper describes a new radiation shielding material, amethyst ore. We have determined the elemental composition of amethyst using WDXRF spectroscopy technique. To see the shielding capability of amethyst for several photon energies, these results have been used in simulation process by FLUKA Monte Carlo radiation transport code. Linear attenuation coefficients have been calculated according to the simulation results. Then, these values have been compared to a fine shielding concrete material. The results show that amethyst shields more gamma beams than concrete. This investigation is the first study about the radiation shielding properties of amethyst ore.

  7. METALLOGENIC SYSTEM OF DACHANG TINPOLYMETALLIC ORE FIELD

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-bin; DAI Ta-gen; WANG Zhi-bin; FANG Sheng-kui

    2001-01-01

    The Dachang tin-polymetallic ore field in northern Guangxi,China,lies in a mid-late Paleozoic rift that borders up the southern boundary of the Jiangnan-Xuefeng Massif.As a giant ore deposit,it deposited in middle of the Nandang-Hechi metallogenic zone.The orehosting strata are of the Devonion,which shows the evident characteristics of polymetallic elements,i.e: ,Sn,Zn,Pb,Sb,As,Cu,Ag,In,Ge,Cd,et al.,and over 1 000 000 t tin reserves.

  8. High-grade iron ore deposits of the Mesabi Range, Minnesota-product of a continental-scale proterozoic ground-water flow system

    Science.gov (United States)

    Morey, G.B.

    1999-01-01

    The Mesabi Range along the north edge of the Paleoproterozoic Penokean orogen in northern Minnesota has produced 3.6 billion metric tons of ore since its discovery in 1890. Of that amount, 2.3 billion metric tons were extracted from hematite- or geothite-rich deposits generally referred to as 'high-grade' ores. The high-grade ores formed as the Biwabik Iron-Formation was oxidized, hydrated, and leached by solutions flowing along open faults and fractures. The source of the ore-forming solutions has been debated since it was first proposed that the ores were weathering products formed by descending meteoritic ground-water flowing in late Mesozoic time. Subsequently others believed that the ores were better explained by ascending solutions, possbily hydrothermal solutions of pre-Phanerzoic age. Neither Wolff nor Gruner could reconcile their observations with a reasonable source for the solutions. In this paper, I build on modern mapping of the Mesabi Range and mine-specific geologic observations summarized in the literature to propose a conceptual model in which the high-grade ores formed from ascending solutions that were part of continent-scale topographic or gravity-driven ground-water system. I propose that the ground-water system was active during the later stages of the development of a coupled fold and thrust belt and foreland basin that formed during the Penokean orogen.

  9. The non-destructive analysis of fluid inclusions in minerals using the proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, C.G.; Van Achterbergy, E. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience; Heinrich, C.A. [ETH Zentrum, Zurich, (Switzerland). Department Erdwissenschaften; Mernagh, T.P. [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany); Zaw, K. [Tasmania Univ., Sandy Bay, TAS (Australia)

    1996-12-31

    The study of ore forming fluids trapped as fluid inclusions in minerals is the key to understanding fluid flow paths at the time of ore formation and to predicting the location of ore bodies within large-scale magmatic hydrothermal systems. The large penetration depths and the predictable nature of MeV proton trajectories and X-ray absorption enables reliable modelling of PIXE yields and the development of standardless quantitative analytical methods. This permits quantitative microanalysis of minerals at ppm levels, and more recently has enabled the development of methods for quantitative trace-element imaging and the quantitative, non-destructive analysis of individual fluid inclusions. This paper reports on recent developments in Proton Microprobe techniques with special emphasis on ore systems and fluid inclusion analysis. 6 refs., 2 figs.

  10. Practice and prospect on bioleaching of uranium ore in China

    International Nuclear Information System (INIS)

    Developing situation on bioleaching of uranium ore in China is introduced. The selection and domestication of bacteria, development and application of biocntact oxidation tank, and practice on bioleaching of uranium ore in China are retrospeted and prospected. (authors)

  11. Study on ore stacking after blasting for stope leaching uranium

    International Nuclear Information System (INIS)

    Geology of ore deposits, technical conditions, mining methods and blasting parameters of in-situ leaching uranium after blasting for an outcrop ore body are introduced. Long hole blast is beneficial technique and can bring better economic benefits

  12. Partitioning properties of rare earth ores in China

    Institute of Scientific and Technical Information of China (English)

    CHI Ru'an; LI Zhongjun; PENG Cui; ZHU Guocai; XU Shengming

    2005-01-01

    The properties of rare earth partitioning in Chinese industrial rare earth ores were analyzed. Rare earth ores can be divided into the single-mineral type ore with bastnaesite, the multi-mineral type ore with bastnaesite and monazite, and the weathering crust type. Both the Bayan Obo rare earth ore and the Zhushan rare earth ore are a kind of mixed ore, consisting of bastnaesite and monazite. Their rare earth partitionings are strongly enriched in light rare earths, where CeO2 is 50% and the light rare earth partitioning is totally over 95%. The Mianning rare earth ore as well as the Weishan rare earth is a kind of rare earth ore only having bastnaesite. Their rare earth partitionings are also strongly enriched in light rare earths,in which CeO2 is 47% and the light rare earth partitioning is totally over 94%. For the weathering crust type rare earth ore,there are the Longnan rare earth ore, the Xunwu rare earth ore, and the middle yttrium and rich europium ore. In the Longnan rare earth ore, which is strongly enriched in heavy rare earths, Y2O3 is 64.83%, and the heavy and light rare earth partitionings are 89.40% and 10.53%, respectively. In the Xunwu rare earth ore, which is strongly enriched in light rare earths, CeO2 is 47.16%, and the light rare earth partitioning is totally 93.25%. Y and Eu are enriched in the middle yttrium and rich europium ore. Its middle rare earth partitioning is totally over 10%, and Eu2O3 and Y2O3 are over 0.5% and 20%,respectively, which are mainly industrial resources of the middle and the heavy rare earths.

  13. Quantification of heat and fluid flow through time by 3D modeling : an example from the Jeanne d'Arc basin, offshore eastern Canada

    OpenAIRE

    Baur, Friedemann Ulrich Maximilian

    2010-01-01

    Demand for energy is growing rapidly, causing worldwide concerns on security of supply. Petroleum systems modeling in 4 dimensions (cube + time) predicts generation, migration, and quality/quantity of accumulated hydrocarbons in reservoirs, incorporating temperature and pressure through the entire evolution of the basin. A petroleum systems model thus provides the only means to combine all physical aspects (source, trap, seal, and reservoir) and timing (charge) to reduce exploration risk and ...

  14. Making a black shale shine: the interaction of hydrothermal fluids and diagenetic processes

    Science.gov (United States)

    Gleeson, Sarah; Magnall, Joe; Reynolds, Merilie

    2016-04-01

    Hydrothermal fluids are important agents of mass and thermal transfer in the upper crust. This is exemplified by shale-hosted massive sulphide deposits (SHMS), which are anomalous accumulations of Zn and Pb sulphides (± barite) in sedimentary basins created by hydrothermal fluids. These deposits occur in passive margin settings and, typically, there is no direct evidence of magmatic input. Recent studies of Paleozoic deposits in the North American Cordillera (MacMillan Pass and Red Dog Districts) have shown that the deposits are formed in a sub-seafloor setting, where the potential for thermal and chemical gradients is high. Mineralization is characterized by the replacement and displacement of unconsolidated, partially lithified and lithified biosiliceous mudstones (± carbonates), and commonly the sulphide mineralization post-dates, and replaces, bedded barite units in the sediments. The Red Dog District (Alaska, USA) contain some of the largest Zn-Pb deposits ever discovered. The host-rocks are dominantly carbonaceous mudstones, with carbonate units and some radiolarites. The ore forms massive sulphide bodies that replace pyritized mudstones, barite and carbonate units. Lithological and textural relationships provide evidence that much of the ore formed in bioturbated, biosiliceous zones that may have had high primary porosity and/or permeability. Sediment permeability may have been further modified by aging of the silica rich sediments and the dissolution/replacement of carbonate and barite beds. At the Tom and Jason deposits (MacMillan Pass, Yukon) the fault-controlled hydrothermal upflow zone is uniquely preserved as an unequivocal vent complex. Here, the metal bearing fluids are hot (300°C), low salinity (6 wt% NaCl equiv.) and acidic (pH Red Dog deposits, reduced sulphur was generated during open system diagenesis and euxinic conditions were not present at the time of mineralization. Furthermore, the formation of diagenetic barite provided an important

  15. Extreme light rare earth element mobilization by diagenetic fluids in the geological environment of the Oklo natural reactor zones, Franceville basin, Gabon

    Science.gov (United States)

    Cuney, Michel; Mathieu, Régis

    2000-08-01

    The anomalously high Th/La ratio (˜1.14) of the Early Proterozoic silicified sandstones of the Franceville basin (Gabon), compared to Archean and Proterozoic metasedimentary rocks (Th/La ˜0.27), results from extreme light rare earth element (REE) migration during diagenesis. Monazite, which represents the main light REE-bearing phase in the sandstones, was altered by diagenetic brines at 140 °C and 1 kbar. The alteration phase is a microcrystalline Th-silicate phase, indicating low Th solubility at these conditions. Light REEs are simultaneously leached out together with P and U. The increase in Th/La from detrital monazite to residual Th-silicate phase indicates that about 76% of the light REEs were leached out, corresponding to a global amount of 2.01 × 109 metric tons at the scale of the FA Formation in the Franceville basin. Uranium was also leached during monazite alteration and may have contributed significantly to the genesis of the high-grade uranium deposits of the Franceville basin that host the natural nuclear reaction zones.

  16. Geology and geochemistry of the Reocín zinc-lead deposit, Basque-Cantabrian Basin, Northern Spain

    Science.gov (United States)

    Velasco, Francisco; Herrero, Jose Miguel; Yusta, Inaki; Alonso, Jose Antonio; Seebold, Ignacio; Leach, David

    2003-01-01

    fluids responsible for sulfide deposition and the infilling of karst cavities were broadly contemporaneous, indicating a post-Albian age. Vitrinite reflectance data are consistent with previously measured fluid inclusion temperatures and indicate temperatures of ore deposition that were less than 100??C. Carbon and oxygen isotopic data from samples of regional limestone, host-rock dolostone and ore-stage dolomite suggest an early hydrothermal alteration of limestone to dolostone. This initial dolomitization was followed by a second period of dolomite formation produced by the mixing of basinal metal-rich fluids with local modified seawater. Both dolomitization events occurred under similar conditions from fluids exhibiting characteristics of basinal brines. The ??34S values of sulfides are between -1.8 and +8.5 per mil, which is consistent with thermochemical sulfate reduction involving organic matter as the main source of reduced sulfur. Galena lead isotope compositions are among the most radiogenic values reported for Zn-Pb occurrences in Europe, and they are distinct from values reported for galena from other Basque-Cantabrian deposits. This suggests that a significant part of the lead was scavenged from the local underlying Asturian sediments. The stratigraphic and structural setting, timing of epigenetic mineralization, mineralogy, and isotopic geochemistry of sulfide and gangue minerals of the Reoci??n deposit are consistent with the features of most of Mississippi Valley-type ore deposits.

  17. Heap leaching of clay ish uranium ores

    International Nuclear Information System (INIS)

    This paper describes an experimental facility, built near El Lobo mine. In it we study the beneficiation of low-grade uranium ore. The mineral has a great amount of clay and fines. The flow-sheet used has four steps: head leaching, ph-ajustement, ion-exchange and participation. We show, also, the most interesting results. (Author)

  18. HANDLING, STORAGE AND IRON ORE QUALITY

    Directory of Open Access Journals (Sweden)

    Fabiana Fonseca Fortes

    2012-06-01

    Full Text Available This paper aims to identify handling and storage impact in iron ore quality, in their physical and chemical characteristics most important for a mining. It is tried to show the interferences in iron ore quality caused by the handling equipment and stockpiling. The research is restricted to Complexo Vargem Grande (Vale. The timeline was demarcated based on the formation of stockpiling. The fieldwork enables data collection and distinction of the routine procedures of casual operations handling. The quantitative analysis is conducted by the statistical method. As a conclusion, handling and storage identified are able to insert changes in physical and chemical characteristics of iron ore. Storage contributes to reduce variability of silica and alumina concentrations, but contributes too particle size deterioration. The handling induces degradation and segregation. However, there is the possibility to decrease handling of the ore and to establish the ideal size of stocks on the system in study, improving the efficiency of the system and consequent in global costs.

  19. Crust-Mantle Structures and Gold Enrichment Mechanism of Mantle Fluid System

    Institute of Scientific and Technical Information of China (English)

    邓军; 孙忠实; 王庆飞; 韦延光

    2003-01-01

    Gold enrichment mechanism of ore-forming fluid is the essence of gold metallization.This paper summarizes the distinguishing symbols of mantle fluid and effect of crust-mantlestructure on fluid movement. Fluid moving processes include osmosis, surge, gas-liquid alterna-tion and mutation of fluid speed. During fluid movement, gold will be enriched gradually. Final-ly, a layered circulatory system is illustrated in this paper.

  20. Mining and processing of uranium ores at the Streltsovsky ore field

    Energy Technology Data Exchange (ETDEWEB)

    Ovseytchuk, V.A.; Litvinenko, V.G.; Kultishev, V.I. [Joint Stock Company, Priargunsky Industrial Mining and Chemical Union, Krasnokamensk, Chita Region (Russian Federation)

    2000-07-01

    The uranium deposits of Streltsovsky ore fields provide raw materials for Russian nuclear industry. For this region, it is important to achieve continued and increased activities in the recovery of mineral resources of uranium. Similarly, maintaining the mining and processing of uranium ores ensures the supply of raw materials for the nuclear industry. With the current operations, increasing the mining and processing activities would increase the cost of production of uranium oxides due to decreasing grades of ore body. After a review of the existing economic, technological and natural factors, a solution was proposed based on the joint application of underground mining and ore enrichment and processing with the help of hydrometallurgical process, in-situ leaching. Reduction of operation coasts and creation of radiation-safe working conditions could be achieved with the application of these systems involving concrete hardening in the mines and in-situ leaching of ore. With the help of economic-mathematical modeling, methods for rational application of various technologies could be determined and their processing parameters were specified. A reduction of coasts could be obtained and favorable conditions could be established for improvement in the treatment of lower grade ores by heap leaching. Application of purification of mine waters and tailing pond reduces the influence of the radiation and the impact on the natural environment. (author)

  1. Probing ore deposits formation: New insights and challenges from synchrotron and neutron studies

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Joel, E-mail: joel.brugger@adelaide.edu.a [Division of Mineral, South Australian Museum, Adelaide (Australia); School of Earth and Environmental Sciences, University of Adelaide, Adelaide (Australia); Pring, Allan [Division of Mineral, South Australian Museum, Adelaide (Australia); School of Earth and Environmental Sciences, University of Adelaide, Adelaide (Australia); Reith, Frank [School of Earth and Environmental Sciences, University of Adelaide, Adelaide (Australia); Ryan, Chris; Etschmann, Barbara; Liu, Weihua [CSIRO Exploration and Mining, Melbourne (Australia); O' Neill, Brian; Ngothai, Yung [School of Chemical Engineering, University of Adelaide, Adelaide (Australia)

    2010-02-15

    The understanding of the physico-chemical processes leading to the formation and weathering of ore deposits plays an increasingly important role in mineral exploration. Synchrotron, neutron, and nuclear radiation are contributing to this endeavour in many ways, including (i) support the modelling of ore transport and deposition, by providing molecular-level understanding of solvent-solute interaction and thermodynamic properties for the important metal complexes in brines, vapours, and supercritical fluids over the range of conditions relevant for the formation of ore deposits (i.e., temperature 25-600 deg. C; pressure 1-10{sup 9} Pa; and fluid compositions varying from hypersaline (e.g., >50 wt% NaCl) to volatile-rich (e.g., CO{sub 2}, CH{sub 4}, and H{sub 2}S)); (ii) track the fluids that travelled through rocks and predict their ore-forming potential by analysing hydrothermal minerals and remnants of those fluids trapped in these minerals as 'fluid inclusions'; (iii) characterize the biochemical controls on metal mobility in soils to predict the geochemical footprint of a buried mineral deposit. X-ray fluorescence (XRF), particle-induced X-ray emission (PIXE), and X-ray absorption spectroscopy (XAS) are the most common techniques used in support of mineral exploration. Analytical challenges are related to (i) the complexity of heterogeneous natural samples, which often contain only low concentrations of the elements of interest; (ii) beam sensitivity, especially for redox-sensitive elements in aqueous fluids or biological samples; (iii) extreme sample environments, e.g., in-situ study of fluids at high pressure and temperature. Thus, critical improvements need to be made on a number of fronts to: (i) develop more efficient detectors, able to map large areas in heterogeneous samples (e.g., 10{sup 6}-10{sup 8} pixels per map), and also to collect a maximum number of photons to limit sample exposure and beam damage; (ii) integrate techniques (e.g., XRF

  2. Oxidizing roasting enhances extraction of uranium from some refractory ores

    International Nuclear Information System (INIS)

    Roasting in an oxidizing environment improves extraction of uranium from some refractory ores. Roasting of the ore tested also tends to reduce reagent costs and handling problems. Ores that may benefit from roasting include those of low uranium extractability that contain oxidizable organic materials or clay minerals. Roasting improves the porosity of ores by removing carbonaceous material and dehydrating clays, and it may even break down agglomerates of a clay-silica-organic nature. The result is better access of the leaching agent to the uranium-containing fractions of the ore

  3. Study on the Physical and Chemical Conditions of Ore Formation of Hetai Ductile Shear Zone-Hosted Gold Deposit and Discovery of Melt Inclusions

    Institute of Scientific and Technical Information of China (English)

    李兆麟; 翟伟; 李文; 石贵勇; 文拥军

    2002-01-01

    The Hetai ductile shear zone-hosted gold deposit occurs in the deep-seated fault mylonite zone of the Sinian-Silurian metamorphic rock series. In this study there have been discovered melt inclusions, fluid-melt inclusions and organic inclusions in ore-bearing quartz veins of the ore deposit and mylonite for the first time. The homogenization temperatures of the various types of inclusions are 160℃, 180 - 350℃, 530℃ and 870℃ for organic inclusions, liquid inclusions, two-phase immiscible liquid inclusions and melt inclusions, respectively. Ore fluid is categorized as the neutral to basic K+ -Ca2+ -Mg2+ -Na+ - SO2- 4-HCO3-Cl- system. The contents of trace gases follow a descending order of H2O>CO2>CH4>(or < ) H2>CO>C2H2>C2I-I6>O2>N2.The concentrations of K , Ca2 + ,SO2-4,HCO3-,Cl- H2O and C2H2 in fluid inclusions are related to the contents of gold and the Au/Ag ratios in ores from different levels of the gold deposit. This is significant for deep ore prospecting in the region. Daughter minerals in melt inclusions were analyzed using SEM. Quartz, orthoclase, wollastonite and other silicate minerals were identified. They were formed in different mineral assemblages.This analysis further proves the existence of melt inclusions in ore veins. Sedimentary metamorphic rocks could form silicate melts during metamorphic anatexis and dynamic metamorphism, which possess melt-solution characteristics. Ore formation is related to the multi-stage forming process of silicate melt and fluid.

  4. Algal—Bacterial Fabrics of Ores and Their Genetic Implications in the Longtang Lead—Zinc Deposit at Yanbian,Sichuan

    Institute of Scientific and Technical Information of China (English)

    帅德权; 张寿庭; 等

    1995-01-01

    The Longtang Pb-Zn deposit occurs in the Upper Sinian Guanyinyan For-mation.The host rocks include sandy shale,cherty limestone and dolomitic limestone.The deposit is a typical one of thallogen origin.The mineral assemblage in the ore is made up of sphalerite, galena, pyrite, enargite, tennantite, seligmannite, asphalt, etc.The ore-forming process is possessed of multi-episode and multi-stage characters. Generally, sphalerites exhibit algal stromatolitic, bac-terial and algal colloidal textures, providing evidence for the direct involvement of alage and bacteria in mineralization of ore-forming elements during sedimentary diagenesis. This is the first transmigration of ore-forming elements.However, pyrite embracing bac-teria and galena replacing/filling trichomes are typical organic textures, which are related to organic carbon and bitumen that can adsorb or reduce ore-forming elements. This is an indirect process of organic mineralization ,ie.,the second transmigration of ore-forming elements.&34S values are all greater than 5%o,indicating the dominance of the heavy sulfur isotopes.The ore-forming temperature deduced from fluid inclusions ranges from 100℃to 150℃±.All this goes to show that the Longtang Pb-Zn deposit is of thallogen origin.

  5. High-rate behaviour of iron ore pellet

    Science.gov (United States)

    Gustafsson, Gustaf; Häggblad, Hans-Åke; Jonsén, Pär; Nishida, Masahiro

    2015-09-01

    Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

  6. High-rate behaviour of iron ore pellet

    Directory of Open Access Journals (Sweden)

    Gustafsson Gustaf

    2015-01-01

    Full Text Available Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

  7. Hydraulic Conductivity of Compacted Laterite Treated with Iron Ore Tailings

    Directory of Open Access Journals (Sweden)

    Umar Sa’eed Yusuf

    2016-01-01

    Full Text Available The objective of this study was to investigate the effect of iron ore tailings (IOT on hydraulic conductivity of compacted laterite. The IOT conforms to ASTM C 618-15 Type F designations. In the present study, soil was admixed with 0–20% IOT and compacted at moulding water content ranging from 10 to 25% using four types of compactive efforts. Hydraulic conductivities of the compacted soil-IOT mixtures were determined using deionized water and municipal solid waste leachate as the permeant fluids, respectively. Deionized water was the reference permeant fluid. Results of this study showed that hydraulic conductivity decreased with increase in IOT content as a result of improvement in mechanical properties of the soil. Permeation of the soil-IOT mixtures with leachate caused the hydraulic conductivity to drop to less than 1 × 10−9 m/s especially at higher compactive efforts. Also, bioclogging of the soil pores due to accumulation of biomass from bacteria and yeast present in the leachate tends to significantly reduce the hydraulic conductivity. From an economic point of view, it has been found from the results of this study that soil specimens treated with up to 20% IOT and compacted at the British Standard Light (BSL compactive effort met the maximum regulatory hydraulic conductivity of less than or equal to 1 × 10−9 m/s for hydraulic barrier system.

  8. Thermal Fluid Flow in Sedimentary Basins and Its Significance to Pool-form ing Dynamics%沉积盆地热流体活动及其成藏动力学意义

    Institute of Scientific and Technical Information of China (English)

    叶加仁; 杨香华

    2001-01-01

    Based on the analysis and some typical data of petroleum basins in China and world, it discusses some important expression forms and majo r research methods of thermal fluid flow, and emphasized its enhancement to orga nic-matter maturation and hydrocarbon generation in this paper. According to t he major controlling factor, passage of fluid migration, to thermal fluid flow, it divides thermal fluid flow into four types: (1)lithologic-type, (2)conformity -t ype, (3)fault-type and (4) compound-type. Finally, it also discusses the sign ifi cance of thermal fluid flow to pool-forming dynamics:(1)provides a new ex planation way to abnormal vitrinite reflectance, which can enlarge the fields of hydrocarbon exploration and development; (2)provides some important evidences to research of hydrocarbon migration, which support to choose exploration targ e ts; and (3)provides means to study diagnesis and porosity evolution of reservo ir rocks, which can be used to predict the development units of deep reservoir s.%在分析、总结国内外一些含油气盆地的典型资料的基础上,论述了热流体活动的若干重要表现形式及主要研究方法,强调了热流体活动对有机质热演化和油气生成的强化作用。根据控制热流体活动的主要因素之一--流体活动通道,将沉积盆地内的热流体活动类型划分为岩性型、不整合型、断裂型和复合型四大类。最后,探讨了热流体活动对成藏动力学研究的重要意义,认为其可为有机质演化异常提供新的成因解释途径,扩大油气勘探领域;为油气运移的研究提供线索,优化勘探目标选择;为成岩-孔隙演化的动态研究提供依据,预测深部储层发育层段。

  9. A Study on the Role of Pre-Gelatinized Starch (PGS in the Non Damaging Drilling Fluid (NDDF for the Tipam Sand of Geleki Oilfield of Upper Assam Basin

    Directory of Open Access Journals (Sweden)

    Prasenjit Talukdar

    2015-06-01

    Full Text Available The drilling of the wells from surface to target location with conventional drilling fluids may impair production and ultimate recovery by failing to adequately connect the reservoir with the wellbore by damaging the producing interval. One of the most common ways of damaging a formation is the filtration loss. Non Damaging Drilling Fluid (NDDF is a clay and barite free environmental friendly polymer mud system mostly used in pay zone sections of development wells and specifically in horizontal drilling to avoid formation damage. Starches [(C6H10O5 n] are an environment-friendly drilling mud additive for water-base drilling fluids used to control the filtration loss. This paper reports the effect and optimum composition of Pre-Gelatinized Starch (PGS as a filtration control component in the NDDF. PGS is a high-quality nonionic polysaccharide having the Chemical Formula: C27H48O20 and Molecular Weight: 692.658020 [g/mol] which controls the filtration loss by sealing the walls of the borehole due to its long chains of monosaccharide. Some clay specifically the montmorillonite a member of the smectite group that generally also found in the payzones of Geleki Oilfield of Upper Assam Basin absorb hydrogen ions into their structure when comes in contact with fresh water and causing swelling of the clay resulting in a reduction of the pore volume and possibly plug in the pore throats. Therefore the filtration loss should be as low as possible by forming high quality low permeable mud cake of as thin as possible. In this work, an attempt has been made to study the effect of varying composition of PGS on the different mud properties of laboratory formulated NDDF and to choose its optimum composition based on the required mud parameters of the study area.

  10. Geological characteristics of siderites from Longqiao iron deposit in Luzong volcanic basin and their genetic significance%庐枞盆地龙桥铁矿床中菱铁矿的地质特征和成因意义

    Institute of Scientific and Technical Information of China (English)

    段超; 周涛发; 范裕; 袁峰; 丁铭; 尚世贵; 张乐骏

    2009-01-01

    The Longqiao iron deposit is one of the most important large ore deposits in Luzong basin, one of the ore-concentrated area in the Middle and Lower Yangtze Valley metallogenic belt. The genesis of this ore deposit remains a problem of much controversy. Based on careful and detailed field investigation and mineral association research, this paper has reported some new achievements concerning siderite minerals in this deposit. There exist two types of siderites in the ores: one occurs in the lamellar ores, and the other assumes the veined form. Petrographic and electron probe analyses as well as C-O, H-O isotope geochemical characteristics of the siderites in the lamellar ore all show that siderites of this kind were formed earlier than magnetite and other minerals associated with magnetite, and that they occurred in a marine sedimentary environment. Some siderites were transformed into magnetite by later hydrothermal activities, resulting in the formation of residual and metasomatic textures in the ores. The lamellar iron ores are composed of sedimen-tary siderite and hydrothermal minerals such as magnetite, garnet, pyrite and phlogopite as a result of the water-rock interaction be-tween the hydrothermal fluids evolved from the Mesozoic magmatic intrusion and the siderite-beating Early Mesozoic (Middle Trias-sic) marine sedimentary rocks. Most of the magnetites in the ore deposit, espeeiaUy in the massive iron ores, were precipitated direct-ly from the magmatic water-dominated hydrothermal system. The metallogenic process of the Longqiao iron deposit can be divided in-to the early (Middle Triassic) sedimentary ore-forming stage characterized by the deposition of siderite-beating rocks and the late (Early Cretaceous or Yanshanian) hydrothermal ore-forming stage characterized by the formation of magnetites associated with other hydrothermal minerals.%龙桥铁矿床是庐枞火山岩盆地中的一个大型的铁矿床,多年来对其矿床成因的认识存在较大

  11. Uranium deposits of the Sierra Pena Blanca: Three examples of mechanisms of ore deposit formation in a volcanic environment

    International Nuclear Information System (INIS)

    The Nopal and Escuadra Formations (welded vitroclastic tuffs) contain the uranium deposits of Sierra Pena Blanca (Chihuahua, Mexico). These Tertiary formations (between 44 and 38 million years) overlie Cretaceous limestones. With mineralogical, petrographical, geochemical and fluid inclusion studies of the non-altered rocks of the uraniferous mineralization and the associated alteration three genetic types of ore deposits have been identified. Hydrothermal ore deposits (Nopal I). These ore deposits are linked to faults or a breccia pipe. They are mainly located in the Nopal Formation. Their history is complex and begins soon after the deposition of tuff. They are considered hydrothermal, even if some supergene alteration occurs during late stages. Oxidized mineralization (uranophane) succeeds reduced ore (uranium oxides-ilmenite and pitchblende-pyrite associations). The associated kaolinite has a high temperature habitus. The montmorillonite-zeolite association is local and occurs after kaolinization. Supergene ore deposit (Puerto III). Puerto III is a stratiform-shaped deposit. The only oxidized mineralization lies in the upper part of the Nopal Formation and is located under a silicified bed interpreted as a palaeosoil. Mixed ore deposit (Las Margaritas). This uranium-molybdenum deposit is located in the Escuadra Formation. The alteration products are kaolinite with a middle temperature habitus and alunite. The intensity of this alteration is lower than in the first hydrothermal type, but the volume of altered rock is greater. Uranium mineralizations (silicates, phosphates, vanadates) are associated with molybdenum minerals (sulphides and molybdates). This deposit is considered to be the result of an interaction, in a tectonic valley, between hydrothermal volcanic fluids and underground waters. (author)

  12. Constraining the period of hydrocarbon accumulation by fluid inclusion, molecular biomarker and ESR dating techniques: A case study from the Tazhong 45 well, Tarim Basin%塔中45井油气藏成藏期的厘定

    Institute of Scientific and Technical Information of China (English)

    张鼐; 张宝收; 赵瑞华; 杨晓光; 南燕云; 赵澄雨

    2012-01-01

    在塔中45井的萤石中发现两期烃包裹体:第Ⅰ期烃包裹体为产于萤石中的发黄色弱荧光的原生液相烃包裹体,沿萤石生长纹分布,与萤石同生;第Ⅱ期烃包裹体为产于萤石中的发蓝白色强荧光的次生气液相烃包裹体,分布在萤石的愈合缝中,晚于萤石形成.烃包裹体组分分析和赋存矿物测年结果表明,第Ⅰ期油来源于中上奥陶统,是一期成熟油的充注;第Ⅱ期油应形成于喜马拉雅期,主要来源于高成熟的寒武系烃源岩,是由寒武系原油裂解后再一次大规模轻质油侵入而形成的,第Ⅱ期是奥陶系萤石层段的油气藏主要成藏期.%Two distinct generations of hydrocarbon inclusions are found in vein fluorite from the Ordovician carbonate reservoirs in the Tazhong 45 well, Tarim Basin. The first generation of inclusions is characterized by weak yellow fluorescence, liquid phase, and distribution along the fluorite growth bands. The second generation of inclusions is of strong white fluorescence, gas-liquid phase, and occurrence in the suture lines of fluorite. Based on an integrated investigation of trapping temperature, formation water salinity, molecular compositions of the aqueous and petroleum fluid inclusions, and isotope and ESR dating of the host minerals, it is concluded that: (1) the fluorite vein was formed by a deep fluoride-rich fluid brought into the Ordovician carbonate formation through deep faults during the Permian; (2) the fluoride-rich fluid was a low temperature hydrothermal fluid probably generated from an acidic magmatic activity in the region during the Late Hercynian; (3) the charge of mature liquid hydrocarbons from the Middle-Upper Ordovician source rock was concomitant with the fluorite crystallization in the Tazhong 45 carbonate reservoirs, which resulted in the formation of the first generation of petroleum inclusions in the fluorite growth bands; (4) the second generation of hydrocarbon inclusions

  13. Introduction - Acid decomposition of borosilicate ores

    International Nuclear Information System (INIS)

    The complex processing of mineral raw materials is an effective way for the extraction of valuable components. One of these raw materials are borosilicate ores from which the boric acid, aluminium and iron salts and building materials can be obtained. In the Institute of Chemistry of the Academy of Sciences of the Republic of Tajikistan the flowsheets of the processing of borosilicate raw materials by acid and chloric methods were elaborated. The acid methods of decomposition of borosilicate ores of Ak-Arkhar Deposit were considered in present monograph. The carried out researches on elaboration of physicochemical aspects and technological acid methods allowed to define the optimal ways of extraction of valuable products from borosilicate raw materials of Tajikistan.

  14. Bioleaching of a manganese and silver Ore

    International Nuclear Information System (INIS)

    The bioleaching with a strain of Thiobacillus thiooxidans of the ore of Farallon Negro (Catamarca, Argentina) was studied in order to estimate its application to the solution and recovery of the manganese, and to improve the silver extraction. The State company which works the mine has not yet found an economical process to extract the manganese and has only reached a 30% efficiency in the recovery of silver by cianuration. The effects of pulp density variations and the addition of different quantities of FeS were analysed looking for the best working conditions. 74 μm (mesh Tyler 200) of ore particles were used because that is the size used in this plant for the cianuration process. (Author)

  15. The giant Bayan Obo REE-Nb-Fe deposit, China:Controversy and ore genesis

    Institute of Scientific and Technical Information of China (English)

    Hong-Rui Fan; Kui-Feng Yang; Fang-Fang Hu; Shang Liu; Kai-Yi Wang

    2016-01-01

    Bayan Obo ore deposit is the largest rare-earth element (REE) resource, and the second largest niobium (Nb) resource in the world. Due to the complicated element/mineral compositions and involving several geological events, the REE enrichment mechanism and genesis of this giant deposit still remains intense debated. The deposit is hosted in the massive dolomite, and nearly one hundred carbonatite dykes occur in the vicinity of the deposit. The carbonatite dykes can be divided into three types from early to late:dolomite, co-existing dolomite-calcite and calcite type, corresponding to different evolutionary stages of carbonatite magmatism based on the REE and trace element data. The latter always has higher REE content. The origin of the ore-hosting dolomite at Bayan Obo has been addressed in various models, ranging from a normal sedimentary carbonate rocks to volcano-sedimentary sequence, and a large carbonatitic intrusion. More geochemical evidences show that the coarse-grained dolomite represents a Mesoproterozoic carbonatite pluton and the fine-grained dolomite resulted from the extensive REE mineralization and modification of the coarse-grained variety. The ore bodies, distributed along an EeW striking belt, occur as large lenses and underwent more intense fluoritization and fenitization. The first episode mineralization is characterized by disseminated mineralization in the dolomite. The second or main-episode is banded and/or massive mineralization, cut by the third episode consisting of aegirine-rich veins. Various dating methods gave different mineralization ages at Bayan Obo, resulting in long and hot debates. Compilation of available data suggests that the mineralization is rather variable with two peaks at w1400 and 440 Ma. The early mineralization peak closes in time to the intrusion of the car-bonatite dykes. A significant thermal event at ca. 440 Ma resulted in the formation of late-stage veins with coarse crystals of REE minerals. Fluids involving in

  16. Thirty years of ore processing in Spain

    International Nuclear Information System (INIS)

    Spain's experience with the processing of uranium ores covers pegmatitic ores, vein-type deposits, sandstone ores, enrichments in metamorphic sediments, radioactive coals and nonconventional sources such as phosphoric acid and copper waters. Studies have also been conducted for the treatment of very poor ores, such as palaeozoic quartzites. The recovery of by-products (copper) is included in this experience. The technologies employed range from physical concentration, combustion and calcination to conventional treatment with acids and alkalis and leaching under pressure, static leaching and bacterial leaching. Special attention has been devoted to the recovery of uranium from liquids and the development of equipment for this purpose (especially for solvent extraction and continuous ion-exchange techniques). This activity has not been limited to conventional-size plants of 500-3000t/d. Interest in the development of small or remote mines has led to the creation of transportable and re-usable modular plants. Reducing the environmental impact is another aspect of interest. The purification of uranium concentrates and the manufacture of products of nuclear purity, both by wet (nitric acid - TBP) and by dry processes (fluidized beds), is another field in which Spain has made progress. The experience acquired in these 30 years of research and industrial practice and the innovative projets set up for the future could well serve as a good basis for other medium-sized countries wishing to establish a uranium industry. A description of the Spanish experience, indicating what is worth pursuing and what should be avoided, may help new countries to join the circle of uranium producers. (author)

  17. Geological and geochemical studies of the Shujiadian porphyry Cu deposit, Anhui Province, Eastern China: Implications for ore genesis

    Science.gov (United States)

    Wang, Shiwei; Zhou, Taofa; Yuan, Feng; Fan, Yu; White, Noel C.; Lin, Fengjie

    2015-05-01

    Most porphyry deposits in the world occur in magmatic arc settings and are related to subduction of oceanic plates. A small proportion of porphyry deposits occur in intracontinental settings, however they are still poorly understood. Shujiadian, a newly-discovered porphyry Cu deposit, is located in the Middle-Lower Yangtze River Valley metallogenic belt and belongs to the intracontinental class. The deposit has classic alteration zones defined by a core of potassic alteration and local Ca-silicate alteration, which is overprinted by a feldspar-destructive alteration zone and cut by veins containing epidote and chlorite. Wallrocks of the deposit are unreactive quartz-rich sedimentary rocks. Three main paragenetic stages have been recognized based on petrographic observations; silicate stage, quartz-sulfide stage, and sulfide-carbonate stage. Quartz + pyrite + chalcopyrite ± molybdenite veins, and quartz + chalcopyrite + pyrite veins of the quartz-sulfide stage contribute most of the copper, and chalcopyrite + chlorite ± pyrite ± pyrrhotite ± quartz ± illite veins of the sulfide-carbonate stage also contribute part of the copper; all the mineralized veins are associated with feldspar-destructive alteration. Investigations on the fluid inclusions in Shujiadian indicate that the ore-forming fluids had four evolutionary episodes: immiscibility and overpressure in the silicate stage, boiling in the quartz-sulfide stage and mixing with meteoric water in the sulfide-carbonate stage. Sulfur and strontium isotope studies suggest that ore metals were mainly derived from magmatic-hydrothermal fluids, and combined with our study of fluid inclusions, we infer that decompression, changes in oxygen fugacity and sulfur content were the main factors that caused Cu precipitation. Compared with porphyry deposits in magmatic arc settings, there are some differences in the ore-bearing rock, alteration, and the composition of ore-forming fluids.

  18. Study of fluid inclusion from uranium deposit No.302 in north Guangdong

    International Nuclear Information System (INIS)

    The temperature of fluid inclusions in gangue minerals such as calcite, quartz, fluorite was measured and carbon isotope composition of Calcite was studied for uranium deposit No.302 in north Guangdong in this paper. It shows that the homogeneous temperature and salinity decreased from the early ore-forming period to late ore-forming period, and the early ore-forming period had at least two-staged fluid process with medium-high temperature and salinity. The carbon isotopic composition of δ13CPDB of calcites of different stages are: -0.614%--0.971% which indicates that the carbon maybe came from deep crust. (authors)

  19. Characteristics of sulfur isotope during the epigenetic alteration of oil-gas and coalbed methane in the southeastern Songliao Basin

    International Nuclear Information System (INIS)

    Through studying the characteristics of pyrite and sulfur isotope in the rock of Upper Cretaceous Quantou Formation, Yaojia Formation and Nenjiang Formation in the southeastern Songliao Basin, occurrence features of pyrite and characteristics of sulfur isotope in gray and grayish-green sandstone produced by epigenetic reducing decoloration of Quantou Formation and Yaojia Formation indicate the characteristics of organic fluid composition in deep-seated oil-gas and coalbed methane. δ34SV-CDT of sulfur isotope in original sedimentary diagenite is positive, δ34SV-CDT of organic fluid in oil-gas and coalbed methane is negative. Reduction of oil-gas and coalbed methane not only makes mottled and purplish-red original oxidized sandstone reduce to grey and grayish-green reducing sandstone, which makes the reducing capacities of rocks increase greatly, but also uranium is superimposed and enriched during the interaction of rocks with organic fluid of oil-gas and coalbed methane and uranium content increases generally, which results in the forming of uranium anomaly and mineralization in some areas. Stockwork damouritization is discovered in the ore-bearing sandstone of Yaojia Formation in Menda area at the first time, which shows the uranium mineralization is characterized by low temperature hydrothermal alteration and is related with low temperature hydrothermal fluid. (authors)

  20. Pros and Cons,Iron Ore Price Hikes

    Institute of Scientific and Technical Information of China (English)

    Tang Jingtao

    2008-01-01

    @@ Backaround Baostecl and CVRD reached an agreement on the price hikes of 65 percent and 71 percent in February.And in June Baosteel and Rio Tinto which is the largest iron ore company in Australia reached an agreement on the price hikes of 79.88 percent on the iron ore fines and 96.5 percent on the iron ore lumps.This is the first time that two kinds of the iron ore price grew at the same time in Asian market.

  1. Sulfuric acid leaching of mechanically activated manganese carbonate ore

    Directory of Open Access Journals (Sweden)

    Kenan Yıldız

    2010-06-01

    Full Text Available Acidic leaching of mechanically activated manganese ore from Denizli – Tavas was investigated. The ore was activated mechanically in a planetary mill and the amorphisation in manganese structure was analyzed with X-ray diffraction. The parameters in acidic leaching of the ore were milling time, acid concentration and time. All experiments were performed at 25°C with solid to liquid ratio: 1/10. The activation procedure led to amorphization and structural disordering in manganese ore and accelerated the dissolution of manganese in acidic media.

  2. Study on the Physical and Chemical Conditions of Ore Formation of Hetai Ductile Shear Zone—Hosted Gold Deposit and Discovery of Melt Inclusions

    Institute of Scientific and Technical Information of China (English)

    李兆麟; 翟伟; 等

    2002-01-01

    The Hetai ductile shear zone-hosted gold deposit occurs in the deep-seated falut mylonite zone of the Sinian-Silurian metamorphic rock series.In this study there have been discovered melt inclusions,fluid-melt inclusions and organic inclusions in ore-bearing ruartz veins of the ore deposit and mylonite for the first time.The homogenization temperatures of the various types of inclusions are 160℃,180-350℃,530℃and 870℃ for organic inclusions,liquid inclsions two-phase immiscible liquid inclusions and melt inclusion,respectively,Ore fluid is categoriezed as the neutral to basic K+-Ca2+-Mg2+-Na+-SO42--HCO3-Cl- system.The contents of trace gases follow a descending order of H2O>CO2>CH4>(orCO>C2H2>C2H6>O2>N2.The concentrations of K+,Ca2+,SO42-,HCO3-,Cl-,H2O and C2H2 in fluid inclusions are related to the contents of gold and the Au/Ag ratios in from different levels of the gold deposit.This is significant for deep ore prospecting in the region.Daughter minerals in melt inclusions were analyzed using SEM.Quartz,orthoclase,wollastonite and other silicate minerals were identified.They were formed in different mineral assemblages.This analysis further proves the existence of melt inclusions in ore veins.Sedimentary metamophic rocks could form silicate melts during metamorphic anatexis and dynamic metamorphism,which possess melt-soulution characteristics.Ore formation is related to the multi-stage forming process of silicate melt and fluid.

  3. Deep ancient fluids in the continental crust and their impact on near-surface economic, environmental and biological systems.

    Science.gov (United States)

    Ballentine, Christopher; Warr, Oliver; Sutcliffe, Chelsea; McDermott, Jill; Fellowes, Jonathan; Holland, Greg; Mabry, Jennifer; Sherwood Lollar, Barbara

    2016-04-01

    With a few exceptions the mobility of water, oil and gas, provides for an ephemeral view of subsurface fluids relative to geological or planetary timescales. Aquifers supplying water for drinking and irrigation have mean residence ages from hundreds to tens of thousands of years; Hydrothermal systems can be active for hundreds of thousands to millions of years forming key mineral reserves; Sedimentary basin formation expels fluids during compaction and generates oil and gas on times scales of millions to hundreds of millions of years. Within these exemplar systems biological activity can play a crucial role by mediating system oxidation state: releasing arsenic into shallow groundwaters; precipitating ore bodies; generating methane; and biodegrading oil. It is becoming increasingly apparent that fluids resident in fractures and porespace in the crystalline basement underlying many of these systems can have a mean residence time that ranges from tens to hundreds of millions of years [1,2] to billions of years [3,4]. These fluids are highly saline and trace element rich; they are abundant in nitrogen, hydrogen, methane and helium and can contain microbes that have uniquely adapted to these isolated environments [5]. We are actively expanding discovery of sites with fluids exhibiting extreme age and have recently shown that these systems contribute to half of the terrestrial hydrogen production; a key component in biosphere energy and carbon cycles [6]. Tectonic or thermal release of these fluids can result in helium deposits; possible ore body generation and the inoculation of near-surface systems with microbial biota protected in the deep surface; the controls and rate of fluid release to shallow systems can fundamentally change the nature of some shallow systems. These deep ancient fluids represent a little tapped scientific resource for understanding how life survives and evolves in such isolation, how life is transported and communicates in extremis together and

  4. Role of ore mineralogy in optimizing conditions for bioleaching low-grade complex sulphide ores

    Institute of Scientific and Technical Information of China (English)

    P. A. OLUBAMBI; S. NDLOVU; J. H. POTGIETER; J. O. BORODE

    2008-01-01

    The role that ore mineralogy plays in understanding and optimizing the conditions favouring the bioleaching of complex sulphide ore containing high amounts of siderite was studied using mixed cultures of mesophilic bacteria, with emphasis on zinc,lead and copper recoveries. The influencing parameters investigated include particle size, stirring speed, volume of inoculum, pulp density, and pH. The results show that the mixed mesophilic cultures can extract about two and a half times the amount of zinc than copper over an equivalent period of time. The highest zinc and copper recoveries of 89.2% and 36.4% respectively are obtained at particle size of 75 μm, stirring speed of 150 r/min, pulp density of 10% (w/v), 12% (v/v) inoculum concentration, and a pH of 1.6. Variations in elemental composition within different particle sizes resulting from the mineralogy of the ore account for the bioleaching behaviour at varying particle sizes. The dissolution at varying pulp density, volume of inoculum, solution pH and the low solution potential observed are also influenced by ore mineralogy.

  5. Mercury exposure aboard an ore boat.

    OpenAIRE

    Roach, Richard R; Busch, Stephanie

    2004-01-01

    Two maritime academy interns (X and Y) were exposed to mercury vapor after spilling a bottle of mercury on the floor in an enclosed storeroom while doing inventory aboard an ore boat. During a 3-day period, intern Y suffered transient clinical intoxication that resolved after he was removed from the environment and he showered and discarded all clothing. His initial serum mercury level dropped from 4 ng/mL to < 0.05 ng/mL. Intern X had an initial level of 11 ng/mL, which continued to rise to ...

  6. Upgrading of boron ores and colemanite flotation

    International Nuclear Information System (INIS)

    Processes applied for the processing and upgrading of sodium and calcium borates in Turkey are described. Details of froth flotation study where a low grade colemanite ore containing calcite and clays as a gangue minerals are given. It has been found that, at the natural pH of a colemanite-containing pulp (pH=9,2) it is possible to float colemanite selectively using dodecyl benzene sulphonate or its combinations with a non-polar reagent or naphthenic acids. (author)

  7. Geochemistry and S, Pb isotope of the Yangla copper deposit, western Yunnan, China: Implication for ore genesis

    Science.gov (United States)

    Yang, Xi-An; Liu, Jia-Jun; Cao, Ye; Han, Si-Yu; Gao, Bing-yu; Wang, Huan; Liu, Yue-Dong

    2012-07-01

    The Yangla copper deposit, situated in the middle section of Jinshajiang tectonic belt between Zhongza-Zhongdian block and Changdu-Simao block, is a representative and giant copper deposit that has been discovered in Jinshajiang-Lancangjiang-Nujiang region in recent years. There are coupled relationships between Yangla granodiorite and copper mineralization in the Yangla copper deposit. Five molybdenite samples yielded a well-constrained 187Re-187Os isochron age of 233.3 ± 3 Ma, the metallogenesis is therefore slightly younger than the crystallization age of the granodiorite. S, Pb isotopic compositions of the Yangla copper deposit indicate that the ore-forming materials were derived from the mixture of upper crust and mantle, also with the magmatic contributions. In the late Early Permian, the Jinshajiang Oceanic plate was subducted to the west, resulting in the formation of a series of gently dipping thrust faults in the Jinshajiang tectonic belt, meanwhile, accompanied magmatic activities. In the early Late Triassic, which was a time of transition from collision-related compression to extension in the Jinshajiang tectonic belt, the thrust faults were tensional; it would have been a favorable environment for forming ore fluids. The ascending magma provided a channel for the ore-forming fluid from the mantle wedge. After the magma arrived at the base of the early-stage Yangla granodiorite, the platy granodiorite at the base of the body would have shielded the late-stage magma from the fluid. The magma would have cooled slowly, and some of the ore-forming fluid in the magma would have entered the gently dipping thrust faults near the Yangla granodiorite, resulting in mineralization.

  8. Isotope Geochemistry of Gold Ore Deposits in the Gezhen Shear Zone, Qiongxi, Hainan Island

    Institute of Scientific and Technical Information of China (English)

    夏勇

    2004-01-01

    Gold deposits hosted in the Gezhen shear zone at Qingxi, Hainan Island occur in the Precambrian metamorphic rock series and are regionally developed in the N-E direction along the tectonic zone. From northeast to southwest are distributed the Tuwaishan-Baoban gold mining district, the Erjia gold mining district and the Bumo gold mining district, making up the most industrially important gold metallogenesis zone on the Hainan Island. Isotope geochemical studies of the typical gold deposits in this metallogenesis zone indicate that their ore-forming materials stemmed largely from the Baoban Group migmatite series, though the involvement of some plutonic materials could not be ruled out. The ore fluids are the mixture of migmatitized hydrothermal solutions and meteoric waters in addition to the involvement of local magmatic hydrothermal solutions. The superimposition of plutonic materials and magmatic hydrothermal solutions is controlled by the deformation environment of the shear zone and later magmatic activities. Obvious variations are noticed in isotopic composition in the region studied, probably related to tectonic deformation, metamorphism and other evolutionary characteristics. This study is of great significance in understanding the relationship between the shear zone and gold metallogenesis, the rules of gold metallogenesis and gold ore prognosis.

  9. REE characteristics of Shannan deposit district in Xiangshan uranium ore field and its geological significance

    International Nuclear Information System (INIS)

    REE geochemical characteristics of rock and ore are studied in Shannan deposit district of Xiangshan Uranium orefield. The mean values of Σ REE of both basement schist and volcanic rock are approximately equal. Σ REE gradually increases from rock, common ore to bonanza. REE distribution patterns of rocks are right declined type to light REE. REE distribution patterns of volcanic rock series are parallel and concordant, the volcanic rock series are homologous, and products of pulsating events of same magma chamber. Eu depletes remarkably in volcanic rock series and ores. On its way to surface, magma underwent high fractionation and crystallization, based on feature of REE component ratio, triangle diagram of light medium and heavy REE, and diagram of LREE/HREE-(Eu/ΣREE) × 100. U and REE enriched in hydrothermal solution of post-magmatism to provide substances for uranium metallogenesis. Both diagenesis of volcanic rock series and uranium metallogenesis in the mining district are constrained by volcano-magmatism. Metallogenic fluid is rich in volatiles, such as F, Cl, CO2 etc. Metallogenic substances are unloaded in reduction environment. Metallogenic temperature is probably less than 250℃. Genesis of bonanza is more complicated and likely superimposed by multi-metallogenesis. (authors)

  10. Helium-argon isotopic tracing for the Pb-Zn-Ag polymetallic ore deposits in the central-south segment of the Da Hinggan Ling Range

    Institute of Scientific and Technical Information of China (English)

    WANG Baode; NIU Shuyin; SUN Aiqun; HU Huabin; LIU Yaming; GUO Lijun; WANG Shuo

    2008-01-01

    In recent years big strides have been made in the exploration of ores in the central-south segment of the Da Hinggan Ling Range, though some debates still exist on the metallogenesis and sources of ore-forming materials.Pyrite and other sulfides in direct relation to the Pb-Zn-Ag ore deposits were chosen for the He and Ar isotopic analysis of ore-forming fluids, and the first He and Ar isotope data have been obtained from the study region.3He/4He ratios in 14 samples collected from 7 mining districts are 2.17x10-6-12.52×10-6, averaging 6.86×10-6 and their R/Ra ratios are 1.56-9.01 Ra, averaging 4.37 Ra. By projecting the data points onto the 3He-4He concentrations diagram, all the points fall near the mantle helium area. The calculated mantle-source helium ratios are within the range of 19.58%-76.96%, with an average of 49.52%. Argon isotopic characteristics are close to those of mantle source, indicating that the ore-forming material was transport upwards via the multi-stage evolution of mantle plume and concentrated as ores in the favorable loci of mantle branch structures.

  11. Hydrocarbon-mediated gold and uranium concentration in the Witwatersrand Basin, South Africa

    Science.gov (United States)

    Fuchs, Sebastian; Williams-Jones, Anthony; Schumann, Dirk; Couillard, Martin; Murray, Andrew

    2016-04-01

    The Witwatersrand deposits in South Africa represent the largest repository of gold in the World and a major resource of uranium. The genesis of the gold and uranium ores in the quartz-pebble conglomerates (reefs), however, is still a matter of considerable discussion. Opinion has been divided over whether they represent paleo-placers that have been partly remobilised by hydrothermal fluids or if the mineralisation is entirely hydrothermal in origin. In addition, recently published models have proposed a syngenetic origin for the gold involving bacterially-mediated precipitation from meteoric water and shallow seawater. An important feature of the gold and uranium mineralisation in the reefs is the strong spatial association with organic matter. In some reefs, up to 70% of the gold and almost the entire uranium resource is spatially associated with pyrobitumen seams, suggesting a genetic relationship of the gold-uranium mineralisation with hydrocarbons. Here we report results of a study of the Carbon Leader Reef, using high-resolution scanning and transmission electron microscopy (SEM / TEM) and LA-ICP-MS that provide new insights into the role of hydrocarbons in the concentration of the gold and uranium. A detailed examination revealed gold monocrystals containing numerous rounded or elliptical inclusions filled with pyrobitumen. We interpret these inclusions to record the crystallisation of the gold around droplets of a hydrocarbon liquid that migrated through the Witwatersrand basin, and was converted to pyrobitumen by being heated. We propose that the gold was transported in a hydrothermal fluid as a bisulphide complex and that this fluid mixed with the hydrocarbon liquid to form a water-oil emulsion. The interaction between the two fluids caused a sharp reduction in fO2 at the water-oil interface, which destabilised the gold-bisulphide complexes, causing gold monocrystals to precipitate around the oil droplets. In contrast to the gold, uraninite, the principal

  12. Origin of Gold—Bearing Fluid and Its Initiative Localization Mechanism in Xiadian Gold Deposit,Shandong Province

    Institute of Scientific and Technical Information of China (English)

    邓军; 孙忠实; 等

    2002-01-01

    The composition of quartz inclusions and trace elements in ore indicate that gold-bearing fluid in the Xiadian gold deposit,Shandong Province,stemmed from both mantle and magma,belonging to a composite origin.Based on theoretical analysis and high temperature and high pressure experimental studies,gold-bearing fluid initiative localization mechanism and the forming environment of ore-host rocks are discussed in the present paper.The composite fluid extracted gold from rocks because of its expanding and injecting forces and injecting forces and flew through ore-conducive structures,leading to the breakup of rocks.The generation of ore-host faults and the precipitation of gold-bearing fluid occurred almost simultaneously.This study provides fur-ther information about the relationships between gold ore veins and basic-ultrabasic vein rocks and intermediate vein rocks,the spatial distribution of gold ore veins and the rules governing the migration of ore fluids.

  13. Distribution and Control Factors of Fluids in Ordovician Reservoirs in Tahe Oil Field, Tarim Basin%塔河油田奥陶系油气藏流体分布与受控因素

    Institute of Scientific and Technical Information of China (English)

    丁勇

    2016-01-01

    Fluids are varied and complex in physical property due to greatly different longitudal and lateral distribution of the fluids in Ordovician reservoirs in Tahe Oil Field, Tarim Basin. It is shown that the early hydrocarbon accumula-tion and placement and the later charging and adjustment are the main mechanism of forming the Ordovician reservoirs in this field. The sealing condition of cap rock is the important control factor. The local lateral blocking of compact limestone and controlling of large faults are the cause of regional differentiation in hydrocarbon property and reservoir types. Correspondingly independent fracture-cavity system and multi-phased hydrocarbon accumulation lead the fluids greatly different in plane and vertical extent. Hydrocarbon is generally lighter in the upper and heavier in the lower of the reservoirs, and it is commonly lighter in the south and the east of the field and it is heavier in the north and the west. The depth of bottom water is evidently different in every fracture-cavity system because of the trap evolvement and the dynamic condition.%塔河油田奥陶系油气藏流体类型复杂,流体分布纵横向差异较大。通过分析流体分布的受控因素,认为早期成藏改造、晚期充注调整是塔河油田奥陶系油气藏重要的成藏机制,成藏封闭条件的形成与演化是油气成藏的重要控制因素。局部受致密石灰岩侧向封挡和大型断裂分割的控制,造成不同区域油气性质及油气藏类型存在差异;相对独立的缝洞系统,以及受油气藏多期成藏所控制,造成流体性质在平面上及纵向上差异较大;受盖层完整性及后期多期改造程度的影响,造成各区及区内流体性质的差异;受圈闭演化以及各成藏期动力条件变化的影响,各缝洞系统油藏底部水体深度差异明显。

  14. Mineral paragenesis, geochemistry and geochronology investigations of the Carlin-type gold deposits at the Goldstrike property, northern Nevada: Implications for ore genesis, igneous petrogenesis and mineral exploration

    Science.gov (United States)

    Almeida, Carolina Michelin De

    The Goldstrike property is located in northern Nevada and contains one of the largest and highest-grade Carlin-type gold deposits. The majority of the Eocene Au mineralization (e.g., Ore I) is hosted in intensely altered Paleozoic lower plate impure carbonate rocks, and is characterized by strong to moderate silicification, higher calculated pyrite and ore-related element concentrations (e.g., As, Cu, Hg, Ni, Tl, Sb, W, and Zn) than Ore II, which is weakly altered. However, both ore types contain similar Au concentration in whole rock and pyrite chemistry analyses. Lithogeochemical and microprobe data suggest that the Paleozoic sedimentary rocks may have been a major source of Cd, Mo, Ni, U, V, and Zn and minor As, Cu, Hg, and Se. The Jurassic lamprophyre dikes might have been a significant source of Ba, Co, and Se, and minor Au, and some of the Jurassic and Eocene intrusive rocks may have provided some Fe. Moreover, the Eocene magmas are interpreted to be the main source of auriferous mineralizing fluids. Trace element abundances and ratios of the Jurassic intrusive rocks suggest that they are shoshonitic and formed from a metasomatized mantle-derived magma, crystal fractionation, and crustal contamination. The Eocene dikes, also shoshonitic, are considerably more evolved and contaminated than the studied Jurassic rocks. Furthermore, Ar-Ar results show that the Jurassic rocks were negligibly affected by the Eocene thermal event, and that temperature of mineralizing fluids were below the closure temperature of biotite (gold deposits at the studied area. In this model, Au and the ore-related elements were exsolved along with volatiles by degassing of a deep and large plutonic complex during its early stage of crystallization. As these magmatic-hydrothermal fluids moved upward along major conduits (e.g., NNW-striking faults), they may have interacted with a Fe-rich fluid, pervasively altering the Paleozoic impure carbonate rocks (e.g., carbonate dissolution

  15. Juuru Mihkli Kiriku Oreli Fond võttis endale uue ülesande / Tauno Kibur

    Index Scriptorium Estoniae

    Kibur, Tauno

    2009-01-01

    Oreli fond on võtnud ülesandeks restaureerida koguduse ajalooline pastoraat. Hoone eskiisi tegi Raivi Juks. Oreli restaureerimist ja tulemust jääb fikseerima Juuru oreli plaat, mille muusikapalad mängis sisse Kristel Aer

  16. Ore-bearing hydrothermal metasomatic processes in the Elbrus volcanic center, the northern Caucasus, Russia

    Science.gov (United States)

    Gurbanov, A. G.; Bogatikov, O. A.; Dokuchaev, A. Ya.; Gazeev, V. M.; Abramov, S. S.; Groznova, E. O.; Shevchenko, A. V.

    2008-06-01

    Precaldera, caldera, and postcaldera cycles are recognized in the geological evolution of the Pleistocene-Holocene Elbrus volcanic center (EVC). During the caldera cycle, the magmatic activity was not intense, whereas hydrothermal metasomatic alteration of rocks was vigorous and extensive. The Kyukyurtli and Irik ore-magmatic systems have been revealed in the EVC, with the former being regarded as the more promising one. The ore mineralization in rocks of the caldera cycle comprises occurrences of magnetite, ilmenite, pyrite and pyrrhotite (including Ni-Co varieties), arsenopyrite, chalcopyrite, millerite, galena, and finely dispersed particles of native copper. Pyrite and pyrrhotite from volcanics of the caldera cycle and dacite of the Kyukyurtli extrusion are similar in composition and differ from these minerals of the postcaldera cycle, where pyrite and pyrrhotite are often enriched in Cu, Co, and Ni and millerite is noted as well. The composition of ore minerals indicates that the hydrothermal metasomatic alteration related to the evolution of the Kyukyurtli hydrothermal system was superimposed on rocks of the caldera cycle, whereas the late mineralization in rocks of the postcaldera cycle developed autonomously. The homogenization temperature of fluid inclusions in quartz and carbonate from crosscutting veinlets in the apical portion of the Kyukyurtli extrusion is 140-170°C and in quartz from geyserite, 120-150°C. The temperature of formation of the chalcopyrite-pyrite-pyrrhotite assemblage calculated using mineral geothermometers is 156 and 275°C in dacite from the middle and lower portions of the Malka lava flow and 190°C in dacite of the Kyukyurtli extrusion. The hydrothermal solutions that participated in metasomatic alteration of rocks pertaining to the Kyukyurtli ore-magmatic system (KOMS) and formed both secondary quartzite and geyserite were enriched in fluorine, as evidenced from the occurrence of F-bearing minerals-zharchikhite, ralstonite,

  17. PRACTICAL AND PREDICTIVE MODELLING OF ORE DEPOSITS IN HYDROTHERMAL SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chong-bin; B.E.Hobbs; H.B.Muhlhaus; A.Ord

    2001-01-01

    @@ Over the past five years,we have been making efforts to develop a practical and predictive tool to explore for giant ore deposits in hydrothermal systems.Towards this goal,a significant progress has been made towards a better understanding of the basic physical and chemical processes behind ore body formation and mineralization in hydrothermal systems.

  18. Excited response of granular ores in vibrating field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dynamical theory was utilized to probe into the law of the excited response of granular ores generated by the exciting action of exciter and the influence of wave propagation in vibrating field. The exciter with double axes was presented as an example, and the principle of exciter and its mathematical expression of the excitation force were given. The granular ores have viscidity and damping speciality, on the basis of which the motion equation of excited response of ores was established and the approximate expression of mode-displacement by harmonic excitation and the steady effect solution of coordinate response were deduced. Utilizing the step-by-step integration method, the recursion relation matrix of displacement, velocity and acceleration of the excited response of ores were obtained, and the computational flow chart and a computational example were given. The results show that the excited response can change the dynamical character and the flowing characteristic of granular ores.

  19. Mineralogy and trace element geochemistry of the Co- and Cu-bearing sulfides from the Shilu Fe-Co-Cu ore district in Hainan Province of South China

    Science.gov (United States)

    Wang, Zhilin; Xu, Deru; Zhang, Zhaochong; Zou, Fenghui; Wang, Li; Yu, Liangliang; Hu, Mingyue

    2015-12-01

    Hosted within the metamorphosed, neritic siliciclastic rocks and sedimentary carbonates of the Proterozoic Shilu Group, the Shilu Fe-Co-Cu ore district in Hainan Province of South China comprises the upper Fe- and the lower Co-Cu ore layers. Combined with the field observation, the mineralogical and geochemical studies of sulfides using electron microprobe and laser ablation ICP-MS analyses recognized three types of Co-Cu ores. Type I is represented by massive ores and mainly comprises the first generation of pyrite (PyI) which occurred either as recrystallized, subhedral to euhedral microcrystal aggregates (PyIa) or as elongated, fine-grained euhedral grains (PyIb) with an orientated alignment parallel to S1 foliation. Type II is banded, disseminated and brecciated ores, and composed of the second generation of pyrite (PyII) which displays internal rhythmic growth zoning, the first generations of chalcopyrite (CcpI) and pyrrhotite (PoI), and associated Co-(Ni)-(As)-sulfide minerals. Type III occurring as veins or veinlets mainly consists of the third generation of pyrite (PyIII) and the second generations of chalcopyrite (CcpII) and pyrrhotite (PoII), of which PyIII appears as subhedral to euhedrall grains or as rims of composite pyrite. The moderate Co and As, and high Ni contents as well as the low Co/Ni ratios (∼2-5) in PyI indicate a sedimentary-metamorphic origin for Type I ores. The higher Co, Ni and As concentrations in PyIb relative to PyIa likely was related to an inhomogeneous deformation-metamorphism. The highest Co (av. 51,195 ppm) in PyII and Ni (av. 3374 ppm) in PoI most likely were linked to the preferred incorporation of Co into pyrite and Ni into pyrrhotite. Combined with the high Ag concentrations in CcpI (av. 266 ppm) and PyII (av. 13.32 ppm), the high Co/Ni ratios in PyII (av. 1241) suggest the derivation of Type II ores from a Co-Cu-Ni-Ag-rich hydrothermal fluid. Further, up to 9 wt.% Co concentrations in PyII show a temperature condition of

  20. Application of low-temperature thermochronology to hydrothermal ore deposits: Formation, preservation and exhumation of epithermal gold systems from the Eastern Rhodopes, Bulgaria

    Science.gov (United States)

    Márton, István; Moritz, Robert; Spikings, Richard

    2010-03-01

    New low-temperature thermochronological data have been used to quantify the protracted, Eocene-Miocene cooling histories of upper and lower plate rocks of the Kesebir-Kardamos extensional dome, Eastern Rhodopes, Bulgaria. 40Ar/ 39Ar and apatite fission-track data reveal that the lower plate has experienced continuous cooling and exhumation, since the Late Eocene. Muscovite 40Ar/ 39Ar plateau ages of 36.90 ± 0.16 Ma and 37.28 ± 0.19 Ma (2 σ) from metamorphic rocks of the footwall reveal the approximate time span during which they cooled below ˜ 350 °C during exhumation caused by detachment faulting. The sedimentary rock-hosted gold mineralization, which represents a thermal event at ˜ 250-220 °C, developed during the early stage of basin formation between 34.71 ± 0.16 Ma and 35.36 ± 0.21 Ma (adularia 40Ar/ 39Ar plateau ages; 2 σ). The termination of hydrothermal mineral deposition at Ada Tepe occurred contemporaneously with the earliest phase of calc-alkaline type magmatism at Iran Tepe (33.97 ± 0.36 Ma to 34.62 ± 0.46 Ma, hornblende and biotite 40Ar/ 39Ar plateau ages, 2 σ). Thermal history modelling of apatite fission-track data shows that the lower plate rocks cooled through ˜ 120 °C at ˜ 18.3 ± 1.9 Ma (1 σ). A time-temperature model obtained from zircon and apatite fission-track data from the upper plate reveals that it was being buried during the late Eocene. At ˜ 33-30 Ma, a dramatic change of the time-temperature path was caused by the initiation of horst-graben structures, resulting in rapid exhumation of the upper plate. Our new thermochronological data reveal many aspects of the mechanisms of formation of sedimentary rock-hosted gold deposits. The heat accumulated during sedimentary burial of the upper plate is a plausible heat source to drive hydrothermal fluid circulation and ore formation. The development of large half-graben basins in the hanging walls of detachment faults, accompanied by a favourable climate, may have created a

  1. Summary of the mineralogy of the Colorado Plateau uranium ores

    Science.gov (United States)

    Weeks, Alice D.; Coleman, Robert Griffin; Thompson, Mary E.

    1956-01-01

    In the Colorado Plateau uranium has been produced chiefly from very shallow mines in carnotite ores (oxidized vanadiferous uranium ores) until recent deeper mining penetrated black unoxidized ores in water-saturated rocks and extensive exploration has discovered many deposits of low to nonvanadiferous ores. The uranium ores include a wide range from highly vanadiferous and from as much as one percent to a trace of copper, and contain a small amount of iron and traces of lead, zinc, molybdenum, cobalt, nickel, silver, manganese, and other metals. Recent investigation indicates that the carnotite ores have been derived by progressive oxidation of primary (unoxidized) black ores that contain low-valent uranium and vanadium oxides and silicates. The uranium minerals, uraninite and coffinite, are associated with coalified wood or other carbonaceous material. The vanadium minerals, chiefly montroseite, roscoelite, and other vanadium silicates, occur in the interstices of the sandstone and in siltstone and clay pellets as well as associated with fossil wood. Calcite, dolomite, barite and minor amounts of sulfides, arsenides, and selenides occur in the unoxidized ore. Partially oxidized vanadiferous ore is blue black, purplish brown, or greenish black in contrast to the black or dark gray unoxidized ore. Vanadium combines with uranium to form rauvite. The excess vanadium is present in corvusite, fernandinite, melanovanadite and many other quadrivalent and quinquevalent vanadium minerals as well as in vanadium silicates. Pyrite and part or all of the calcite are replaced by iron oxides and gypsum. In oxidized vanadiferous uranium ores the uranium is fixed in the relatively insoluble minerals carnotite and tyuyamunite, and the excess vanadium commonly combines with one or more of the following: calcium, sodium, potassium, magnesium, aluminum, iron, copper, manganese, or barium, or rarely it forms the hydrated pentoxide. The relatively stable vanadium silicates are little

  2. Monitoring of natural radioactivity in manganese ore

    International Nuclear Information System (INIS)

    The natural radionuclides (238U, 232Th, and 40K) contents of Manganese ore collected by Sinai Manganese Company in Egypt-Cairo have been determined by low background spectroscopy using hyper-pure germanium (HPGe) detector. The mean activities due to the three radionuclides (238U, 232Th, and 40K) were found to be 3543 ± 106, 222 ± 6.6 and 3483 ± 104 Bq/kg, respectively. The absorbed dose rates due to the natural radioactivity in samples under investigation ranged from 1522 ± 45 to 1796 ± 53 nGy/h. The radium equivalent activity varied from 3807 ± 114 to 4446 ± 133 Bq/kg. Also, the representative external hazard index values for the corresponding samples were estimated.

  3. Rigid Ideals and Radicals of Ore Extensions

    Institute of Scientific and Technical Information of China (English)

    Chan Yong Hong; Tai Keun Kwak; S. Tariq Rizvi

    2005-01-01

    For an endomorphism σ of a ring R, Krempa called σ a rigid endomorphism if aσ(a) = 0 implies a= 0 for a ∈ R. A ring R is called rigid if there exists a rigid endomorphism of R. In this paper, we extend the σ-rigid property of a ring R to an ideal of R. For a σ-ideal Ⅰ of a ring R, we call Ⅰ a σ-rigid ideal if aσ(a) ∈Ⅰ implies a ∈Ⅰ for a ∈ R. We characterize σ-rigid ideals and study related properties. The connections of the prime radical and the upper nil radical of R with the prime radical and the upper nil radical of the Ore extension R[x; σ, δ], respectively, are also investigated.

  4. Ceramic colorant from untreated iron ore residue.

    Science.gov (United States)

    Pereira, Oscar Costa; Bernardin, Adriano Michael

    2012-09-30

    This work deals with the development of a ceramic colorant for glazes from an untreated iron ore residue. 6 mass% of the residue was added in suspensions (1.80 g/cm(3) density and 30s viscosity) of white, transparent and matte glazes, which were applied as thin layers (0.5mm) on engobeb and not fired ceramic tiles. The tiles were fired in laboratory roller kiln in a cycle of 35 min and maximum temperatures between 1050 and 1180°C. The residue and glazes were characterized by chemical (XRF) and thermal (DTA and optical dilatometry) analyses, and the glazed tiles by colorimetric and XRD analyses. The results showed that the colorant embedded in the transparent glaze results in a reddish glaze (like pine nut) suitable for the ceramic roof tile industry. For the matte and white glazes, the residue has changed the color of the tiles with temperature. PMID:22795839

  5. Alternative leaching processes for uranium ores

    International Nuclear Information System (INIS)

    Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

  6. Mercury exposure aboard an ore boat.

    Science.gov (United States)

    Roach, Richard R; Busch, Stephanie

    2004-06-01

    Two maritime academy interns (X and Y) were exposed to mercury vapor after spilling a bottle of mercury on the floor in an enclosed storeroom while doing inventory aboard an ore boat. During a 3-day period, intern Y suffered transient clinical intoxication that resolved after he was removed from the environment and he showered and discarded all clothing. His initial serum mercury level dropped from 4 ng/mL to footwear earlier than intern Y. Intern X's continued exposure due to mercury in the contaminated boots during the 2 weeks before hospitalization was presumed to be the cause. Removing his footwear led to resolution of his toxic symptoms and correlated with subsequent lowered serum mercury levels. Chelation was initiated as recommended, despite its uncertain benefit for neurologic intoxication. Mercury is used in the merchant marine industry in ballast monitors called king gauges. New engineering is recommended for ballast monitoring to eliminate this hazard. PMID:15175181

  7. ANALYSIS ON THE ORE-FORMING CONDITIONS OF THE SANDSTONE TYPE URANIUM DEPOSIT IN THE NORTHEAST UPLIFT OF SONGLIAO BASIN%松辽盆地东北隆起区砂岩型铀矿成矿条件分析

    Institute of Scientific and Technical Information of China (English)

    杨海波; 钟延秋

    2011-01-01

    运用水成矿理论,对松辽盆地东北隆起区砂岩型铀矿成矿的铀源、构造、沉积、水文地质、古气候等条件进行了分析,认为该区具有良好的砂岩型铀矿成矿地质条件.具体表现在区内存在受构造运动影响地层隆起遭受剥蚀的构造天窗,在盆地边缘发育向南西倾斜的斜坡带;有利铀成矿的河流相、三角洲相砂体发育;泥岩-砂岩-泥岩结构层发育良好,有含水透水层和隔水层;补-径-排机制较完善,水动力条件较好,具有渗入型自流水盆地特征.该区具有良好的勘探前景.%With the theory of hydrogenic uranium deposit, the conditions of uranium source, geological structure, hydrology, sedimentation and paleo-climate for the metallogenesis of sandstone type uranium deposits in the northeast uplift of Songliao Basin are analyzed. The following geological conditions are considered favorable for the metallogenesis of sandstone type uranium deposits in this area: Influenced by tectonic movements, stratum uplifting and erosion, a structural inlier is formed in the area; A SW-trending slope belt is developed in the margin of the basin; The well developed sand bodies of fluvial facies and delta facies are deposited; an interlayer zone of mudstone-sandstone-mudstone is developed with permeable bed and impermeable bed; The supply-passage-discharge system is complete with favorable hydraulic condition and the characteristics of secondary seeping artesian basin. As a result, the prospects of uranium in the northeast uplift of Songliao Basin are encouraging.

  8. Fluid structure interaction in piston diaphragm pumps

    OpenAIRE

    Van Rijswick, R.; Van Rhee, C.

    2013-01-01

    Piston diaphragm pumps are used world-wide for the transport of aggressive and/or abrasive fluids in the chemical, mining and mineral processing industries. Figure 1 shows a cross section of a piston diaphragm pump as is used in the mining and mineral processing industries for the transport of mineral ores and tailings in the from of a solid water mixture, called a slurry.

  9. Direct Biohydrometallurgical Extraction of Iron from Ore

    Energy Technology Data Exchange (ETDEWEB)

    T.C. Eisele

    2005-10-01

    A completely novel approach to iron extraction was investigated, based on reductive leaching of iron by anaerobic bacteria. Microorganisms were collected from an anaerobic bog where natural seepage of dissolved iron was observed. This mixed culture was used to reduce insoluble iron in a magnetite ore to the soluble ferrous (Fe{sup +2}) state. While dissolution rates were slow, concentrations of dissolved iron as high as 3487 mg/l could be reached if sufficient time was allowed. A factorial study of the effects of trace nutrients and different forms of organic matter indicated that the best dissolution rates and highest dissolved iron concentrations were achieved using soluble carbohydrate (sucrose) as the bacterial food source, and that nutrients other than nitrogen, phosphorus, potassium, sodium, and acetate were not necessary. A key factor in reaching high levels of dissolved iron was maintaining a high level of carbon dioxide in solution, since the solubility of iron carbonates increases markedly as the quantity of dissolved carbon dioxide increases. Once the iron is dissolved, it has been demonstrated that the ferrous iron can then be electroplated from solution, provided that the concentration of iron is sufficiently high and the hydrogen ion concentration is sufficiently low. However, if the leaching solution is electrolyzed directly, organic matter precipitates at the cathode along with the metallic iron. To prevent this problem, the ferrous iron should be separated from the bulk solution in a more concentrated, purified form. One route to accomplishing this is to take advantage of the change in solubility of ferrous iron as a function of carbon dioxide concentration. By cycling the concentration of carbon dioxide in solution, it is possible to produce an iron-rich concentrate that should be suitable for electrolysis. This represents the first viable hydrometallurgical method for leaching iron directly from ore and producing metallic iron.

  10. The mineralogical characteristics of the hydrothermal types alteration from Nistru ore deposit, Baia Mare metallogenetic district

    Directory of Open Access Journals (Sweden)

    Floarea Damian

    2003-04-01

    Full Text Available The hydrothermal alteration types, which have affected intrusive and volcanic rocks from Nistru ore deposit, are related to fluids composition varied in their evolution within hydrothermal systems. The early stage of the hydrothermal activity has produced extensive propylitisation and potassic alteration (orthoclase, biotite, sericite associated with the central part of the quartz-micromonzodioritic porphyry stock. The late stage of the fluids differentiation is determined by the hydrogen-ion metasomatism (phyllic alteration, argillic alteration, characterized by a large vertical variation. The hydrogen-ion metasomatism is associated with the bor metasomatism, generated by acid solutions and at a high temperature. The vertical and lateral zoning character of the hydrothermal alterations is related to differences in rock composition and variation in physical-chemical conditions during the periods of subvolcanic intrusion and mineralization.

  11. Geological and geochemical characteristics of silicified hydrothermal fluids in Well Shunnan 4 ,Tarim Basin%塔里木盆地顺南4井中硅化热液的地质与地球化学特征

    Institute of Scientific and Technical Information of China (English)

    李映涛; 叶宁; 袁晓宇; 黄擎宇; 苏炳睿; 周瑞琦

    2015-01-01

    塔里木盆地顺南4井奥陶系鹰山组灰岩取心段中发现有明显的热液蚀变现象和交代硅化特征,溶蚀缝洞、疏松硅质灰岩/硅质岩、热液脉体以及粗大石英晶簇异常发育. 通过对取心岩样的地质特征观察,针对热液脉体(方解石脉和石英脉)以及硅质岩样品进行了系统采样,用来进行包裹体测温与测盐、稀土元素和微量元素分析. 结果表明,热液流体具有混合性质,由岩浆活动提供热源,地层水提供主要的流体来源,岩浆热液与地层卤水混合后形成了中 -低温、高盐度的硅化热液. 稀土元素( REE)分析显示,铕异常δEu值为0.040~0.118,平均值为0.069,呈强烈负异常,指示了还原的成岩环境. Sm/Nd值为0.169~0.256,平均值只有0.194,可见成岩流体应该属于壳源流体. 样品REE平均值配分曲线与地壳REE配分曲线趋势高度相似,表明热源来自壳源岩浆,且从其贫Mg2+的特征来看属于上地壳(硅铝层). 微量元素特征中Ba/Sr值为0.43~19.76,平均值为6.70,变化范围较大,亦反应出流体的相对复杂性,U/Th值为0.35~4.76,平均值为2.14,Th/U值为0.21~2.88,平均值为1.03,Th/U-Y/Ho的相关性均显示硅化热液属于低温型热液.%Cores from the Ordovician Yingshan Formation limestone in the of Well Shunnan 4 of the Tarim Basin show remarkable signs of hydrothermal alteration and metasomatism of silicon .Dissolved fracture-cavity,loose siliceous lime-stone/siliceous rock ,hydrothermal veins and large quartz crystal cluster were abnormally developed .Observation of geo-logical characteristics of the samples and analyses of fluid inclusion /rare earth elements and trace element ,all suggested a mixed origin of the thermal fluids .It is believed that igneous activities provided energy and volcanic thermal fluid together with formation water formed a mixture of low-to-medium temperature and high salinity silicified hydrothermal fluid.REE analyses reveal that δEu values

  12. Leaching hydrodynamics of weathered elution-deposited rare earth ore

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Both porosity (φ) and permeability (k) of the weathered elution-deposited rare earth ores are basic hydrodynamic parameters for RE leaching. The relationship between k and φ of two typical rare earth ores of South China in the packed bed was investigated by measuring the flow (Q) under various leaching pressure difference (Δp). The experimental results show that the relationship between k and φ is unique, moreover the relationship between Q and Δp is in accord with the Darcy's law. The effects of the type of ores, the leaching reagents and its concentration, the granule ore size on the leaching permeability have also been investigated. It is demonstrated that kH (for heavy RE ore, kH=35.98 mm2)>kM-H (for middle-heavy RE ore,kM-H=28.50 mm2), whereas k(NH4NO3)>k(NH4Cl)>k[(NH4)2SO4], and the k value increases with increasing leaching reagents concentration and granule ore size(k0.60~0.75 mm=99.96 mm2,k0.125~0.60 mm=11.83 mm2, k0.074~0.125 mm=0.84 mm2).

  13. Chlorine/chloride based processes for uranium ores

    International Nuclear Information System (INIS)

    The CE Lummus Minerals Division was commissioned by The Department of Supply and Services to develop order-of-magnitude capital and operating cost estimates for chlorine/chloride-based processes for uranium ores. The processes are designed to remove substantially all radioactive consituents from the ores to render the waste products harmless. Two processes were selected, one for a typical low grade ore (2 lb. U3O8/ton ore) and one for a high grade ore (50 lbs U3O8 /ton). For the low grade ore a hydrochloric acid leaching process was chosen. For high grade ore, a more complex process, including gaseous chlorination, was selected. Capital cost estimates were compiled from information obtained from vendors for the specified equipment. Building cost estimates and the piping, electrical and instrumentation costs were developed from the plant layout. Utility diagrams and mass balances were used for estimating utilities and consumables. Detailed descriptions of the bases for capital and operating cost estimates are given

  14. METALLURGIC CHARACTERIZATION OF AN IMPORTANT BRAZILIAN MANGANESE LUMP ORE

    Directory of Open Access Journals (Sweden)

    Geraldo Lúcio de Faria

    2014-03-01

    Full Text Available This work proposes a study about important metallurgic parameters of Urucum manganese lump ore, which are: cold and hot particle disintegration mechanisms, heat decompositions and the pre-reduction behavior. A tone of the studied ore was received and representative samples were collected for characterization procedures. Aiming to study ore heat decompositions, it was proposed a quantitative index named Evolution of Heat Decomposition (EHD. Using this index, the chemical and mineralogical characterization data, it was possible to determine the main reactions of mineral decomposition. Two quantitative parameters were proposed to describe the ore solid state reduction; these indexes were named Pre-reduction Efficiency (PE and Pre-reduction Instantaneous Rate (PIR. Applying these parameters it was possible to conclude that Urucum lump ore has a great pre-reduction behavior. The characterization of particle disintegration was performed using three new indexes for manganese ores, which were: Cold Disintegration Index (CDI, Decrepitation Index (DI and Hot Disintegration Index (HDI. These indexes showed that the studied ore did not presents significant cold particle disintegration, but it is susceptive to decrepitation and hot particle disintegration.

  15. Super-Enrichment of Dispersed Elements and Associated Ore Deposits

    Institute of Scientific and Technical Information of China (English)

    高振敏; 姚林波

    2004-01-01

    Dispersed elements do not always occur as associated elements in the ore deposits of other elements. Instead, they can constitute independent ore deposits. The focus of this paper is placed on the mechanism of super-enrichment of the four dispersed elements TI, Ge, Se, and Te under favorable geological conditions, where their enrichment coefficients are so high that their abundances can reach n×103-n×104, sometimes even up to n×106 times (e. g. Te) those of the crust. As a result, they can form their independent ore deposits. Studies have shown that such independent ore deposits are mostly distributed in the southwestern part of China, most of which belong to low-temperature ore deposits, ranging in age from Yanshanian to Himalayan(Cretaceous to Cenozoic), with a significant time gap with the host strata. Moreover, this paper also deals with the existing forms (as independent minerals, occurring isomorphously and being adsorbed) of the dispersed elements in those independent ore deposits. The discovery of independent ore deposits of dispersed elements is a great breakthrough in the study of dispersed element metallogenesis.

  16. Source of ore-forming materials of the Cangpo carbonate replacement tin deposit in the Dachang tin field: evidence from oxygen, carbon and hydrogen isotopes

    International Nuclear Information System (INIS)

    The Dachang tin field with more than one hundred million tonnes of ore at 1% tin and 3% Zn is one of the largest tin fields in the world. The deposit hosted by middle Devonian limestone, argillaceous limestone and black shale, is genetically related to the Longxianggei granite. The oxygen, hydrogen and carbon isotope data of minerals, rocks and fluids suggest a magnatic fluid which evolved during the crystallization of the Longxianggei granite. Mass balance calculations show that the depletions observed in 180 and 13C values of calcites from the ore bodies to the country rocks were due to continous isotopic exchange reactions between the magmatic fluid and the marine limestones at different W/R ratios and between 300 and 600 deg.C. 7 refs., 4 figs

  17. Geochemical and Nd isotopic constraints on provenance and depositional setting of the Shihuiding Formation in the Shilu Fe-Co-Cu ore district, Hainan Province, South China

    Science.gov (United States)

    Yu, Liangliang; Zou, Shaohao; Cai, Jianxin; Xu, Deru; Zou, Fenghui; Wang, Zhilin; Wu, Chuanjun; Liu, Meng

    2016-04-01

    The Shihuiding Formation, a subordinate succession hosting the Fe-Co-Cu ores, is a suite of Neoproterozoic terrigenous clastic rocks occurring in the Shilu Fe-Co-Cu ore district of the Hainan Island, South China. Integrated petrographical, geochemical, and Nd isotopic analyses have been carried out on 23 sandstone specimens of the Shihuiding Formation in order to understand their provenance and the tectonic setting of their deposition. The samples can be divided into two groups, quartzose sandstones (13 samples) and ferruginous sandstones (10 samples). The ferruginous sandstones have average SiO2 and Fetotal contents of 77.23 wt.% and 18.09 wt.%, respectively, and this contrasts with the higher average SiO2 (94.04 wt.%) and lower Fetotal (2.67 wt.%) contents of the quartzose sandstones. The bivariant Th/Sc and Zr/Sc ratios indicate a predominantly recycled sedimentary provenance, and the low to medium degrees of weathering are commonly indicated by an average chemical index of maturity (CIM) of 81 and an average chemical index of alteration (CIA) of 68. The Shihuiding Formation sandstones have REE contents of 21-249 ppm, with LREE/HREE = 9.18 and δEu = 0.67. The εNd (970 Ma) values of -5.7 to -3.4, and model (TDM) ages of 2099-1773 Ma are compatible with a source mainly from the Paleo- to Mesoproterozoic Baoban Group, a suite of metamorphosed sedimentary rocks intruded by ca. 1450 Ma granites. Quantitative provenance modeling indicates that the Shihuiding Formation sandstones are best modeled with a mixture of 29% plagioclase-amphibole gneiss (29 P), 38% quartz-muscovite schist (38 Q), and 33% granite (33 G) detritus. Mixing the εNd values of the sandstones, calculated at 970 Ma, indicates that the sediment received 22-47% (average 34%) of its detritus from the Baoban Group quartz-muscovite schists. Components from hydrothermal fluids may also have been involved during deposition of the Shihuiding Formation sandstones, as revealed by a bivariant Al/(Al + Fe + Mn

  18. Intelligent Forecasting of Sintered Ore's Chemical Components Based on SVM

    Institute of Scientific and Technical Information of China (English)

    ZHONG Luo; WANG Qingbo; YUAN Jingling

    2011-01-01

    Using object mathematical model of traditional control theory can not solve the forecasting problem of the chemical components of sintered ore. In order to control complicated chemical components in the manufacturing process of sintered ore, some key techniques for intelligent forecasting of the chemical components of sintered ore are studied in this paper. A new intelligent forecasting system based on SVM is proposed and realized. The results show that the accuracy of predictive value of every component is more than 90%. The application of our system in related companies is for more than one year and has shown satisfactory results.

  19. Biosolubilization of uranyl ions in uranium ores by hydrophyte plants

    International Nuclear Information System (INIS)

    This paper investigated the bioleaching of uranyl ions from uranium ores, in aqueous medium by hydrophyte plants: Lemna minor, Azolla caroliniana and Elodea canadensis under different experimental conditions. The oxidation of U(IV) to U(VI) species was done by the atomic oxygen generated in the photosynthesis process by the aquatic plants in the solution above uranium ores. Under identical experimental conditions, the capacity of bioleaching of uranium ores decreases according to the following series: Lemna minor > Elodea canadensis > Azolla caroliniana. The results of IR spectra suggest the possible use of Lemna minor and Elodea canadensis as a biological decontaminant of uranium containing wastewaters. (author)

  20. Gold-silver-tellurium mineral assemblages in different ore styles of the Southern Urals VHMS deposits

    Science.gov (United States)

    Maslennikov, V. V.; Zaykov, V. V.; Maslennikova, S. P.; Tesalina, S. G.; Herrington, R. J.; Buschmann, B.; Becker, K.; Petersen, S.; Orgeval, J. J.; Leistel, M.

    2003-04-01

    VMS deposits of the South Urals generally show a continuum in degradation and reworking ranging from pristine steep-sided hydrothermal sulphide mounds to deposits dominated by layered strata of clastic sulphides. Four different deposits with varying degrees of degradation in order of increased reworking: (Yaman-Kasy longrightarrow Molodezhnoe longrightarrow Alexandrinskoe longrightarrow Balta-Tau) have been ranged. The influence of sulphide mound destruction and of sea-floor alteration on mineral assemblages was investigated In the pristine Yaman-Kasy sulphide mound gold and silver occur as altaite+tellurium+hessite-stuetzite+sylvanite and later galena+native gold+pyrite assemblages in chalcopyrite+isocubanite-rich linings of former chimney conduits. Chalcopyrite-dominated conduit fragments in clastic ore facies contain native tellurium+gold intergrowths. In the weakly reworked Molodezhnoe deposit gold-silver assemblages only occur in sea-floor altered clastic sulphides on the slope of massive sulphide mounds in bornite- and tennantite-rich ores in association with Cu-Ag sulfides such as jalpaite, mckinstryite, and stromeyerite and rare Au-Ag-tellurides (petzite). The Alexandrinskoe deposit is dominated by clastic ores and here native gold and rare hessite occur together with galena in tennantite-sphalerite-dominated veins of the footwall as well as in drusy sphalerite forming conduits of vent chimneys. An assemblage of electrum+galena+tennantite was observed in secondary chalcopyrite in the outer walls of chimneys. Native gold+stromeyerite are common in bornite-rich clastic sulphides while an assemblage of Ag-sulphosalts+electrum is common in barite-rich ores. In the reworked Balta-Tau deposit Ag-sulphosalts+electrum-kustelite occur often together with tennantite+galena+barite banded ores. Gold-silver-telluride mineralisation in these VMS deposits changes with degree of reworking from Au-tellurides, and native gold+galena+pyrite in pristine sulphide mounds to

  1. Silver-cobalt mineralization in the Upper Seymchan ore cluster, Northeastern Russia

    Science.gov (United States)

    Goryachev, N. A.; Gamyanin, G. N.; Prokof'ev, V. Yu.; Savva, N. E.; Velivetskaya, T. A.; Ignat'ev, A. V.

    2014-09-01

    Canyon Complex and enriched in the light isotope in its oxygen isotopic composition. The mineralization in the Upper Seymchan ore cluster, which is genetically linked to the Early Cretaceous calc-alkaline dike suite pertaining to the period of postcollision late orogenic extension, is formed from magmatic fluids diluted with meteoric water (salinity reaches 20 wt % NaCl equiv) at temperatures varying from 400-380°C to 220-150°C and under a pressure of 970 to 60 bar. The direct vertical mineral zoning is expressed in the change of mineral species with depth and in variable compositions and properties of particular minerals.

  2. 山东牟平宋家沟金矿床流体包裹体研究%Study on fluid inclusions of Songjiagou Gold Deposit in Muping,Shandong Province

    Institute of Scientific and Technical Information of China (English)

    王铎融; 王力; 陈扬

    2015-01-01

    宋家沟金矿床位于胶莱盆地东北缘,牟平—即墨断裂带内,控矿构造为陡倾断裂和裂隙密集带,赋矿围岩为莱阳群的灰白色砾岩,共出露4个矿体. 对区内主成矿阶段石英中的流体包裹体进行了岩相学、显微测温及单个包裹体成分激光拉曼光谱分析. 研究表明,矿石中的包裹体主要有纯CO2包裹体、气液二相包裹体和含CO2三相包裹体3种类型;矿石中的包裹体普遍富含CO2 ,成矿流体为CO2 -NaCl -H2 O 体系,成矿流体具有低盐度(5.0 %~14.42 %)、低密度(0.64 ~0.96 g/cm3 )的特点. 主成矿温度集中在220~240 ℃,成矿压力范围为40~62 MPa,对应的成矿深度为5 .01~6 .34 km. 结合前人研究的流体包裹体氢氧同位素分析认为,宋家沟金矿床的成矿流体以幔源流体为主,后期有少量的岩浆流体参与. 确定其矿床成因类型为受陡倾断裂和裂隙密集带联合控制的中温热液脉型金矿床.%Songjiagou Gold Deposit is located in in Muping-Jimo faults,northeast of Jiaolai Basin.The ore-con-trolling structure is steeply inclined fracture and fissure-intensive belt,the surrounding rocks are pale conglomerates with 4 outcrop orebodies.Petrographic,microthermometric and laser Raman microspectroscopic studies on fluid inclu-sions in quartz of main mineralization stages of Songjiagou Gold Deposit are carried out .The results show that there are three types of fluid inclusions:pure CO2 single-phase fluid inclusions,aqueous two-phrase fluid inclusions and CO2 -bearing fluid inclusions.CO2 are widespread in the fluid inclusions in ores.The fluids of main mineralization stages should be a CO2 -NaCl-H2 O system; The ore-forming fluids are with low salinity (5.0 % to 14.42 %) and low density(0.64 g/cm3 to 0.96 g/cm3 ); Mineralization temperature ranges between 220 ℃ and 240 ℃,mineralization pressure ranges from 40 MPa to 62 MPa,while mineralization depth ranges from 5.01 km to 6.34 km.The paper, based on hydrogen

  3. Evaluation des bassins par modélisation intégrée en deux dimensions des transferts techniques, de l'écoulement des fluides, de la genèse et de la migration des hydrocarbures Basin Evaluation by Integrated Two-Dimensional Modeling of Heat Transfer, Fluid Flow, Hydrocarbon Generation, and Migration

    Directory of Open Access Journals (Sweden)

    Chenet P. Y.

    2006-11-01

    transfer, compaction and water flow, hydrocarbon generation, and two-phase migration of fluids. The model reproduces the influence of conductivity variations and of transient heat transfer on paleotemperatures. Quantitative verification of the paleotemperature reconstruction and of the kinetic model of hydrocarbon generation may be obtained from present temperatures and geochemical data. Compaction-driven flows and overpressures are described by coupling a compaction law with Darcy's law for water flow and a criterion for natural hydraulic fracturing. This formulation allows modeling of overpressures in young deltalic sequences (e. g. , the Mahakam delta, Indonesia as well as in old rift basins (e. g. , the North Sea. An adapted two-phase Darcy's law reproduces primary and secondary migration. In particular, the model helps investigate the role of overpressures and fault behavior on hydrocarbon migration and entrapment. Our results confirm that basin models contribute to the synthesis of geological, geophysical, and geochemical data consistently. By defining parameters for petroleum evaluations, these models increase exploration efficiency.

  4. Sedimentary environment analysis of Yaojia formation--the ore-hosting stratum of Qianjiadian uranium deposit

    International Nuclear Information System (INIS)

    Qianjiadian uranium deposit is the first uranium deposit discovered in Songliao basin. In this paper, the sedimentary environment of Yaojia formation, the ore-hosting stratum of Qianjiadian uranium deposit and its relationship with uranium mineralization are studied from several aspects such as lithological combination, sedimentary structures, logging curves, thickness ratio of sandstone layer to mudstone layer, sedimentary petrology and petrological geochemistry. The sedimentary features are characterized by the average value 5.0 between thickness ratio of sandstone layer to mudstone layer of Yaojia formation, and typical tabular cross bedding and trough cross bedding. The lithology of Yaojia formation is mostly composed of intermediate to fine-grained sandstone and mudstone with less conglomerate, and the debris grains have moderate sorting and roundness. These indicate that the source area is far, and that the sediments underwent long-distance transportation before deposition. The large scale and stable extension sand body of the Yaojia formation demonstrated the sedimentary features ora large sedimentary basins. Therefore, the sedimentary environment of Yaojia formation in the study area should be far-sourced sandy braided stream in the united great Songliao basin. The uranium mineralization of Qianjiadian deposit is mainly controlled by the sand bodies of channel-bar and point-bar subfacies, and the scale of the mineralization is closely related to that of the sand bodies. (authors)

  5. Mineralogy and fluid inclusion studies in kalchoye Copper- gold deposit, East of Esfahan

    Directory of Open Access Journals (Sweden)

    Rezvan Mehvary

    2009-09-01

    Full Text Available Kalchoye Copper-gold deposit is located about 110 kilometers east of Esfahan province and within the Eocene volcano sedimentary rocks. Sandy tuff and andesite lava are important members of this complex.The form of mineralization in area is vein and veinlet and quartz as the main gangue phase. The main ore minerals are chalcopyrite, chalcocite, galena and weathered minerals such as goethite, iron oxides, malachite and azurite. Studies in area indicate that ore mineralization Kalchoye is low sulfide, quartz type of hydrothermal ore deposits and results of thermometry studies on quartz minerals low- medium fluid with low potential mineralization is responsible for mineralization in this area.

  6. Studies on Sulfating Roasting Process for Mianning Bastnasite and Baotou Mixed RE Concentrate Ore

    Institute of Scientific and Technical Information of China (English)

    Miao Guangli

    2004-01-01

    Some processes of sulfating roasting and water leaching of crude Mianning RE concentrate ore, of fine Mianning RE concentrate ore, of Baotou RE concentrate ore and of their mixture were investigated.The result shows that the mixture of Mianning and Baotou RE concentrate ore has the optimum leaching rate and rate of recovery when the mixture ratio is 1:4.The recovery rate of the mixture is higher by 14.76% than that of crude Mianning RE concentrate ore, by 5.0 % than that of Mianning fine RE concentrate ore and by 2.4 % than that of Baotou RE concentrate ore.

  7. Ore mineralogy of the Serra Pelada Au-Pd-Pt deposit, Carajás, Brazil and implications for ore-forming processes

    Science.gov (United States)

    Berni, Gabriel V.; Heinrich, Christoph A.; Lobato, Lydia M.; Wall, Vic

    2016-08-01

    Serra Pelada is a world-class hydrothermal Au-Pd-Pt deposit located at the eastern border of the Amazon craton, northern Brazil. The rocks at Serra Pelada have experienced intense tropical weathering for about 70 Ma, but drill core samples preserve the primary mineralogy and hydrothermal alteration features, with extreme grades of Au, Pd and Pt individually reaching hundreds of parts per million (ppm) by weight. Mineralization at Serra Pelada occurs in hydrothermally altered metasiltstones and dolomitic metasandstones at the hinge zone of a recumbent syncline, comprising zones of hematite, chlorite-carbon, argillic, and siliceous alteration. The main hydrothermal gangue minerals are quartz, kaolinite, sericite, amesite, hematite, monazite, florencite and variable amounts of highly reflective carbonaceous matter. Hydrothermal carbon input is evident from precipitated carbon occurring along crenulation planes and veinlets associated with the precious metals. Ore and accessory minerals include a variety of sulphide, selenide, arsenide, sulphate and oxide minerals, including gold with variable metal contents, palladian gold, fischesserite, sudovikovite, sperrylite, selenian braggite, isomertieite, mertieite-II and secondary Au-Pt-Pd alloys. The composition of fischesserite varies from the ideal formula (Ag3AuSe2) towards a more Ag-rich composition, indicating a disordered solid solution form that is stable only above 260 °C, consistent with the high thermal maturity of associated carbonaceous matter approaching graphite. Primary ore and gangue minerals at Serra Pelada comprise a suite of elements that are best transported in oxidising conditions and precipitated upon reduction. This suggests that fluid mixing between a highly oxidised (metal carrier) and a reduced fluid was a key process for high-grade noble metal precipitation at Serra Pelada.

  8. Potential for use of methylene blue index testing to enhance geotechnical characterization of oil sands ores and tailings

    Energy Technology Data Exchange (ETDEWEB)

    Boxill, Lois [SRK Consulting (Canada)

    2011-07-01

    At the CONRAD conference held in Edmonton in 2011, clay scientist expressed their concern over the variability of clay structures and its impact both on oil sands ores and on tailings. This paper discusses the potential for using methylene blue index testing to enhance geotechnical understanding of the impact of the cation exchange capacity of clay present in oil sands ores and both solid and fluid components of the tailings stream. A description of the methylene blue index test procedure is provided. This process is most commonly used for characterization in the oil sands industry. The requirements for obtaining consistency in the test results are discussed. The test is often used to enhance geotechnical characterization of clays in other areas. The potential for developing correlations between methylene blue index test results and other geotechnical parameters is also discussed. It can be concluded from the study that geotechnical data on soil indicate the effect of clay minerals on the overall plasticity of the soil.

  9. Pulmonary function evaluations of dogs exposed to uranium ore dust

    International Nuclear Information System (INIS)

    Pulmonary function evaluations were conducted on dogs exposed to carnotite uranium ore dust. Significant changes were detected in the slope of the single-breath N2 washout curve, suggesting an uneven distribution of ventilation

  10. Radioanalysis of RE enrichment of ion adsorption type RE ores

    CERN Document Server

    Zhao Shu Quan; Hu He Ping; Li Fu Sheng; Chen Ying Min; LiuShiMing

    2002-01-01

    Objective: To analyze the radioactivity in Rare Earth (RE) enrichment of ion adsorption type RE ores. Methods: Using HPGe-gamma spectrometer to analyze the activity ratio of gamma radionuclides in kind of samples, using FJ-2603 low background alpha, beta measurement apparatus to measure their total alpha and total beta activities, and using X-ray fluorescence spectrometer to analyze contents of La sub 2 O sub 3 and Y sub 2 O sub 3 , respectively. Results: HPGe gamma spectroscopy and X-ray fluorescence spectroscopy are simple, convenient and non-destructive methods of analyzing radionuclides and La sub 2 O sub 3 , Y sub 2 O sub 3 in RE enrichment of ion adsorption type RE ores, respectively. Conclusion: The basic data were provided for radiation protection and treatment of gas, liquid and solid waste in RE production of ion adsorption type RE ores; method and experience were provided for studying ion adsorption type RE ores

  11. ITABIRITE IRON ORE CONCENTRATION BY PNEUMATIC FLOTATION CELL

    Directory of Open Access Journals (Sweden)

    Angelo Quintiliano Nunes da Silva

    2015-06-01

    Full Text Available The main iron ore processing plants in Brazil operate through reverse cationic flotation. Many studies have been conducted in order to improve flotation efficiency by optimization process variables. The pneumatic flotation cell stands out due to the simplicity to and to the intense contact particle/bubble promoted by the pulp feeding system. In this study, laboratory scale and pilot were conducted using a sample of itabirite iron ore. The objectives are evaluating the performance of this device using low grade iron ore, and drawing a comparison with laboratory scale tests on conventional flotation cell. The results indicate the potential application of pneumatic flotation cell to the ore tested. Adjustments in the feed particle size and process optimizations can be performed on the concentrate, reaching Fe and SiO2 grades used by the industry

  12. Hydrogeochemistry of uranium, daughter products and associated elements (lanthanides), application to ore prospection

    International Nuclear Information System (INIS)

    The behavior in ground water of uranium, daughter products with long half life (U234, Th230, Ra226) and stable (radiogenic lead) and lanthanides is studied by two complementary methods: 1) In situ multielement tracing in fracturated granitic rocks and porous sedimentary rocks of low permeability allowing to understand interactions between hydrodynamics and geochemistry. 2) Study of the properties of U234 and Pb236 which are mineralization tracers and are relatively independent of redox conditions, on the contrary U 238 has a low solubility in reducing medium. Three areas are studied: Bazois and Lodeve basin (France) and Cigar Lake (Canada). Radioactive disequilibriums are thoroughly studied when required by ore/rock interaction. Adsorption-desorption phenomena are of great importance in proposed prospection models. If prospection models based on alpha activity ratio U234/U238 and lead isotope ratio in ground water can be applied, an integrated prospection model requires more in situ and laboratory experiments

  13. Discussion on fleet test method for radioactive ore sample

    International Nuclear Information System (INIS)

    Testing radionuclides in building materials sample with γ-ray spectrometry has become a commonly used laboratory method, in view of the activity of radioactive ore is ten times more than the building materials sample,its fleet test is possible. It discusses the fleet test method for radioactivity ore sample from the 'social production' point of view. Achieving the test quickly and effectively within error permission, so the method can enhance the efficiency of test and reduce the economic cost. (authors)

  14. Extraction of lithium Carbonate from Petalite Ore (Momeik District, Myanmar)

    International Nuclear Information System (INIS)

    The methods for preparing high purity lithium carbonate which can be used for pharmaceutical applications, electronic grade crystals of lithium or to prepare battery-grade lithium metal are disclosed. Lithium carbonate as commercially produced from mineral extraction, lithium containing brines or sea water. One method for the production of pure lithium carbonate from mineral source (petalite ore) obtained from Momeik District, Myanmar is disclosed. Method for mineral processing of ore concentrate is also disclosed.

  15. Uranium mobilization from low-grade ore by cyanobacteria

    International Nuclear Information System (INIS)

    Three cyanobacterial isolates (two LPP-B forms and one Anabaena or Nostoc species) from different environments could mobilize uranium from low-grade ores. After 80 days, up to 18% uranium had been extracted from coal and 51% from a carbonate rock by the filamentous cyanobacterium OL3, a LPP-B form. Low growth requirements with regard to light and temperature optima make this strain a possible candidate for leaching neutral and alkaline low-grade uranium ores. (orig.)

  16. Magnetic Characterization of Sulphide Ores: Examples From Sweden

    OpenAIRE

    Jirestig, J.; Forssberg, E.

    1992-01-01

    Diagrams of accumulativemagnetic susceptibility distribution are used to evaluate the suitability of four sulphide ores for magnetic methods of beneficiation. The investigated materials are Garpenberg, Aitik and Kedtrask. The samples were divided into susceptibility classes each of which was characterized by its mineral content. The results are presented as diagrams showing mineral appearance in the whole susceptibility range of the ore. The obtained accumulative susceptibility diagrams can b...

  17. PER - CONCENTRATION OF IRON ORE SLIME IN MAGNETIC SEPARATOR

    OpenAIRE

    Dr. Nirlipta Nayak

    2015-01-01

    Indian iron ore is generally friable in nature that results in generation of significant quantity of fines (around 35%) during mining and processing in the country. The ratio of lumps to fines produced in the country is 2:3. During washing and sizing of the ore, slimes with less than 0.21 mm size are generated and discarded into the tailing pond. It is estimated that around 10 million tons of slimes are being generated in every year during the proces...

  18. NRC's limit on intake of uranium-ore dust

    International Nuclear Information System (INIS)

    In 1960 the Atomic Energy Commission adopted an interim limit on the intake by inhalation of airborne uranium-ore dust. This report culminates two decades of research aimed at establishing the adequacy of that limit. The report concludes that the AEC underestimated the time that thorium-230, a constituent of uranium-ore dust, would remain in the human lung. The AEC assumed that thorium-230 in ore dust would behave like uranium with a 120-day biological half-life in the lung. This report concludes that the biological half-life is actually on the order of 1 year. Correcting the AEC's underestimate would cause a reduction in the permitted airborne concentration of uranium-ore dust. However, another factor that cancels the need for that reduction was found. The uranium ore dust in uranium mills was found to occur with very large particle sizes (10-micron activity median aerodynamic diameter). The particles are so large that relatively few of them are deposited in the pulmonary region of the lung, where they would be subject to long-term retention. Instead they are trapped in the upper regions of the respiratory tract, subsequently swallowed, and then rapidly excreted from the body through the gastrointestinal tract. The two effects are of about the same magnitude but in opposing directions. Thus the present uranium-ore dust intake limit in NRC regulations should provide a level of protection consistent with that provided for other airborne radioactive materials. The report recalculates the limit on intake of uranium-ore dust using the derived air concentrations (DAC) from the International Commission on Radiological Protection's recent Publication 30. The report concludes that the silica contained in uranium-ore dust is a greater hazard to workers than the radiological hazard

  19. Treatment of molybdenite ore with laboratory scale solar furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Coutures, J.P.; Benezech, G.; Renard, R.; Skaggs, S.R.

    1979-01-01

    The conventional method of extracting molybdenite concentrate (MoS/sub 2/) from raw ore consumes 145 x 10/sup 6/ Btu/ton of concentrate in fossil fuel equivalent energy. Processing the ore using a solar hear source could save 56% of this energy. Thermodynamic considerations indicate that MoS/sub 2/ is the easiest of the economically valuable ores to extract using a solar heat source. Oxidation of MoS/sub 2/ to molybdic oxide (MoO/sub 3/) is an exothermic process, and it should proceed autogenically if the concentration of MoS/sub 2/ is high enough. Experiments to measure the specific heat of the raw ore were conducted to determine the crossover point for concentration of molybdenite vs sensible heat of the reaction. The reaction temperatures were measured using a calorimeter, and three distinct reaction temperatures were found. These were identified as water and organic vapors, the oxidation of pyrite (FeS/sub 2/) which is present in the raw ore, and oxidation of the molybdenite. The production rate of SO/sub 2/ was measured for 0.5 g samples of three different concentrations of molybdenite: (1) 95% MoS/sub 2/ concentrate, (2) 10% concentrate mixed with the raw ore, and (3) the unadulterated raw ore. A crude mass balance was obtained between the reacted product (oxide) and the unreacted ore (sulfide) in the hearth. The curves of reacted product vs time look very similar to the curves of SO/sub 2/ gas production as a function of time. Both sets of curves show the reaction is more than 90% complete in one minute.

  20. Present methods for mineralogical analysis of uranium ores

    International Nuclear Information System (INIS)

    Most promising methods of mineralogic analysis of uranium and uranium-containing minerals, ores and rocks are considered. They include X-ray diffraction, electron microscopy and fluorescence spectroscopy methods. Principle physical basis and capabilities of each method are described; examples of its practical application are presented. Comparative characteristic of method for mineralogic analysis of radioactive ores and their reprocessing products is given. Attention is paid to the equipment and various devices for analysis

  1. Development of a process selection method for gold ores using case-based reasoning

    OpenAIRE

    Rintala, Lotta

    2015-01-01

    The ore grade, the geometry of an orebody as well as the mineralogical properties of the ore determine process selection for gold extraction. These factors have an effect on the metallurgical response of an ore to a proposed treatment scheme. The uniqueness of each ore deposit is the main challenge in the extraction process development for any ore. The mineralogical mode of occurrence of gold, gold grain size distribution, host and gangue mineral type, mineral associations and alterations all...

  2. Uranium and thorium recovery in thorianite ore-preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotte, Joao V.M. [Universidade Federal de Alfenas, Pocos de Caldas, MG (Brazil); Villegas, Raul A.S.; Fukuma, Henrique T., E-mail: rvillegas@cnen.gov.br, E-mail: htfukuma@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas

    2011-07-01

    This work presents the preliminary results of the studies aiming to develop a hydrometallurgical process to produce uranium and thorium concentrates from thorianite ore from Amapa State, Brazil. This process comprises two major parts: acid leaching and Th/U recovery using solvent extraction strategies. Thorianite ore has a typical composition of 60 - 70% of thorium, 8 - 10% lead and 7 - 10% uranium. Sulfuric acid leaching operational conditions were defined as follows: acid/ore ratio 7.5 t/t, ore size below 65 mesh (Tyler), 2 hours leaching time and temperature of 100 deg C. Leaching tests results showed that uranium and thorium recovery exceeded 95%, whereas 97% of lead ore content remained in the solid form. Uranium and thorium simultaneous solvent extraction is necessary due to high sulfate concentration in the liquor obtained from leaching, so the Primene JM-T primary anime was used for this extraction step. Aqueous raffinate from extraction containing sulfuric acid was recycled to the leaching step, reducing acid uptake around 60%, to achieve a net sulfuric acid consumption of 3 t/t of ore. Uranium and thorium simultaneous stripping was performed using sodium carbonate solution. In the aqueous stripped it was added sulfuric acid at pH 1.5, followed by a second solvent extraction step using the tertiary amine Alamine 336. The following stripping step was done with a solution of sodium chloride, resulting in a final solution of 23 g L-1 uranium. (author)

  3. Ferrite grade iron oxides from ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Iron oxyhydroxides and hydroxides were synthesized from chemically beneficiated high SiO2/Al2O3 low-grade iron ore (57.49% Fe2O3) rejects and heated to get iron oxides of 96–99.73% purity. The infrared band positions, isothermal weight loss and thermogravimetric and chemical analysis established the chemical formulas of iron-oxyhydroxides as -FeOOH.0.3H2O; -FeOOH.0.2H2O and amorphous FeOOH. The thermal products of all these were -Fe2O3 excepting that of -FeOOH.0.3H2O which gave mainly -Fe2O3 and some admixture of -Fe2O3. The hydrazinated iron hydroxides and oxyhydroxides, on the other hand, decomposed autocatalytically to mainly -Fe2O3. Hydrazine method modifies the thermal decomposition path of the hydroxides. The saturation magnetization, s, values were found to be in the range 60–71 emu g–1 which are close to the reported values for -Fe2O3. Mechanism of the -Fe2O3 formation by hydrazine method is discussed.

  4. Hydrodynamic modeling of magmatic-hydrothermal activity at submarine arc volcanoes, with implications for ore formation

    Science.gov (United States)

    Gruen, Gillian; Weis, Philipp; Driesner, Thomas; Heinrich, Christoph A.; de Ronde, Cornel E. J.

    2014-10-01

    Subduction-related magmas have higher volatile contents than mid-ocean ridge basalts, which affects the dynamics of associated submarine hydrothermal systems. Interaction of saline magmatic fluids with convecting seawater may enhance ore metal deposition near the seafloor, making active submarine arcs a preferred modern analogue for understanding ancient massive sulfide deposits. We have constructed a quantitative hydrological model for sub-seafloor fluid flow based on observations at Brothers volcano, southern Kermadec arc, New Zealand. Numerical simulations of multi-phase hydrosaline fluid flow were performed on a two-dimensional cross-section cutting through the NW Caldera and the Upper Cone sites, two regions of active venting at the Brothers volcanic edifice, with the former hosting sulfide mineralization. Our aim is to explore the flow paths of saline magmatic fluids released from a crystallizing magma body at depth and their interaction with seawater circulating through the crust. The model includes a 3×2 km sized magma chamber emplaced at ∼2.5 km beneath the seafloor connected to the permeable cone via a ∼200 m wide feeder dike. During the simulation, a magmatic fluid was temporarily injected from the top of the cooling magma chamber into the overlying convection system, assuming hydrostatic conditions and a static permeability distribution. The simulations predict a succession of hydrologic regimes in the subsurface of Brothers volcano, which can explain some of the present-day hydrothermal observations. We find that sub-seafloor phase separation, inferred from observed vent fluid salinities, and the temperatures of venting at Brothers volcano can only be achieved by input of a saline magmatic fluid at depth, consistent with chemical and isotopic data. In general, our simulations show that the transport of heat, water, and salt from magmatic and seawater sources is partly decoupled. Expulsion of magmatic heat and volatiles occurs within the first few

  5. Chapter 3. Chloric decomposition of aluminosilicate ores. 3.1. Features of chlorination of aluminium containing ores

    International Nuclear Information System (INIS)

    The features of chlorination of aluminium containing ores are considered in this article. Theoretical aspects of metals, oxides and natural compounds chlorination, specific features of synthesis of various chlorides are considered as well.

  6. KEY ROLE OF METALLOGENIC THEORY OF POLYGENETIC COMPOUND ORE DEPOSITS IN LOCATION PREDICTION OF HIDDEN ORE DEPOSITS IN DIWA REGIONS

    Institute of Scientific and Technical Information of China (English)

    PENG Sheng-lin; LIU Liang-ming; LAI Jian-qing

    2001-01-01

    The metallogenic theory of polygenetic compound ore deposit is the Important basis for location prediction of hidden ore deposits in diwa regions.It can play an important role in each step of prediction research,targeting procedure,acquiring information and integrating information.In this paper,the authors discusses how to construct geological concept by using of the metallogenic theory of polygenetic ore deposits for predicting targeting area,to arrange investigation and detection for getting enough useful information,and to analyze and integrate information for reaching a trustful prediction conclusion.According to these strategies,we conduct a successful prediction of location of hidden ore bodies in the outer of the Fenghuangshan copper mine,a principal producing mine in Tongling Cu-Au district.

  7. Fluid Mechanics.

    Science.gov (United States)

    Drazin, Philip

    1987-01-01

    Outlines the contents of Volume II of "Principia" by Sir Isaac Newton. Reviews the contributions of subsequent scientists to the physics of fluid dynamics. Discusses the treatment of fluid mechanics in physics curricula. Highlights a few of the problems of modern research in fluid dynamics. Shows that problems still remain. (CW)

  8. Sulfate Saturated Hydrous Magmas Associated with Hydrothermal Gold Ores

    Science.gov (United States)

    Chambefort, I.; Dilles, J. H.; Kent, A. J.

    2007-12-01

    -ICP-MS. Yanacocha anhydrite, hosted by amphiboles, are enriched in FeO (up to 0.6 wt%) and present positive anomalies in Eu and SrO (up to 8000ppm in anhydrite blebs hosted by high Al amphibole of the sample RC6). Anhydrite hosted by clinopyroxene (CPx) and low Al amphibole present higher Ce2O3 content (up to 2000ppm in CPx). In comparison, hydrothermal anhydrite analyzed from El Salvador, Butte and Ajo ore deposits contain less SrO (~ 2000 ppm) and no FeO. Pinatubo anhydrite phenocrysts and inclusions from the 1991 Pinatubo dacite yield low FeO contents, except anhydrite included in amphibole. These data suggest FeO in anhydrite is a product of subsolidus diffusion from the host. The breakdown of abundant anhydrite crystals "stored" in the magma may source of SO2-rich hydrothermal fluids that produced the sulfur enrichment (>500 M Tonnes) observed the Yanacocha hydrothermal gold deposits. The two populations of amphibole are evidence of magma mixing in the Yanacocha magmatic rocks. A sulfate-saturated oxidized dacitic magma chamber resided at about 4 to 8 km depth and 800°C was periodically underplated or fed by hydrous sulfate-rich oxidized basaltic-andesite magma. The shape of the irregular anhydrite blebs suggest that these inclusions could have been trapped as an immiscible sulfate- phosphate rich melt, despite the fact that anhydrite normally has a liquidus temperature of 1450°C and the host amphiboles crystallized at no more than 1050°C based on experiments on andesites and dacites.

  9. 新疆塔里木盆地北缘铀矿勘查中高分辨率遥感分析应用%Application of High Resolution Remote Sensing Technology to Uranium Ore Exploration in North Fringe of Tarim Basin, Xingjiang, China

    Institute of Scientific and Technical Information of China (English)

    叶发旺; 刘德长

    2012-01-01

    高分辨率遥感技术(包括高空间分辨率和高光谱分辨率)是新世纪以来地质勘查领域的重要新技术、新方法.本文以新疆塔里术盆地北缘巴什布拉克铀矿区和柯坪地区为例,研究了 Quickbird高空间分辨率卫星遥感技术和CASI(Compact Airborne Spectrographic Imager)/SASI(Shortwave infrared Airborne Spectrographic Imager)航空高光谱遥感技术在铀矿勘查中的应用.首先,介绍了 Quickbird和CASI/SASI高分辨率遥感数据的特点和处理方法;然后,分析了 Quickbird高空间分辨率遥感技术在新疆塔里木盆地北缘巴什布拉克铀矿区油气还原褪色蚀变识别与空间分布规律分析中的应用,为铀矿油气还原成因研究和外围找矿方向提供重要依据;并研究了Quickbird与CASI/SASI两种高分辨率遥感技术在新疆塔里木盆地北缘柯坪地区铀矿勘查中的应用,发现了萨拉姆布拉克铀矿化带及其铀矿化蚀变空间分布特征,确定了铀矿化蚀变类型,预测了铀矿找矿靶区,为该地区铀矿勘查的新突破提供了重要依据.上述应用表明,高分辨率遥感技术在铀矿地质勘查领域可以取得很好的应用效果,值得广大遥感地质工作者今后进一步深入挖掘其应用潜力.%High resolution remote sensing technology ( including high spatial resolution and hyper-spectral resolution) is an important new technology in field of geological exploration since the new century. In order to present the application of high resolution remote sensing technology in geological field, the Quick-bird high spatial resolution satellite remote sensing technology and CASI (Compact Airborne Spectro-graphic Imager)/SASI (Shortwave infrared Airborne Spectrographic Imager) airborne hyper-spectral remote sensing technology were used to mine the uranium exploration information in north fringe of Tarim Basin, Xingjiang, in this paper. In first part, the feature and processing method of Quickbird and CASI

  10. Fluorosilicone and silicone o-ring aging study.

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Robert; Gillen, Kenneth T.

    2007-10-01

    Fluorosilicone o-ring aging studies were performed. These studies examined the compressive force loss of fluorosilicone o-rings at accelerated (elevated) temperatures and were then used to make predictions about force loss at room temperature. The results were non-Arrhenius with evidence for a lowering in Arrhenius activation energies as the aging temperature was reduced. The compression set of these fluorosilicone o-rings was found to have a reasonably linear correlation with the force loss. The aging predictions based on using the observed curvature of the Arrhenius aging plots were validated by field aged o-rings that yielded degradation values reasonably close to the predictions. Compression set studies of silicone o-rings from a previous study resulted in good correlation to the force loss predictions for the fluorosilicone o-rings from this study. This resulted in a preliminary conclusion that an approximately linear correlation exists between compression set and force decay values for typical fluorosilicone and silicone materials, and that the two materials age at similar rates at low temperatures. Interestingly, because of the observed curvature of the Arrhenius plots available from longer-term, lower temperature accelerated exposures, both materials had faster force decay curves (and correspondingly faster buildup of compression set) at room temperature than anticipated from typical high-temperature exposures. A brief study on heavily filled conducting silicone o-rings resulted in data that deviated from the linear relationship, implying that a degree of caution must be exercised about any general statement relating force decay and compression set.

  11. Microbial Beneficiation of Salem Iron Ore Using Penicillium purpurogenum

    Science.gov (United States)

    Mishra, M.; Pradhan, M.; Sukla, L. B.; Mishra, B. K.

    2011-02-01

    High alumina and silica content in the iron ore affects coke rate, reducibility, and productivity in a blast furnace. Iron ore is being beneficiated all around the world to meet the quality requirement of iron and steel industries. Choosing a beneficiation treatment depends on the nature of the gangue present and its association with the ore structure. The advanced physicochemical methods used for the beneficiation of iron ore are generally unfriendly to the environment. Biobeneficiation is considered to be ecofriendly, promising, and revolutionary solutions to these problems. A characterization study of Salem iron ore indicates that the major iron-bearing minerals are hematite, magnetite, and goethite. Samples on average contains (pct) Fe2O3-84.40, Fe (total)-59.02, Al2O3-7.18, and SiO2-7.53. Penicillium purpurogenum (MTCC 7356) was used for the experiment . It removed 35.22 pct alumina and 39.41 pct silica in 30 days in a shake flask at 10 pct pulp density, 308 K (35 °C), and 150 rpm. In a bioreactor experiment at 2 kg scale using the same organism, it removed 23.33 pct alumina and 30.54 pct silica in 30 days at 300 rpm agitation and 2 to 3 l/min aeration. Alumina and silica dissolution follow the shrinking core model for both shake flask and bioreactor experiments.

  12. Flotation technology of refractory low-grade molybdenum ore

    Institute of Scientific and Technical Information of China (English)

    Du Shuhua; Luo Zhenfu

    2013-01-01

    Because of the low grade,high oxidation rate and the accumulation of little associated metal sulfide ore in the molybdenum concentrate during flotation,the Qingyang molybdenum ore is difficult to beneflciate.The experimental studies of grinding fineness,the amount of roughing modifier,depressant and collector were completed.In the cleaning process,the contrast experiments of one regrinding.the regrinding and scrubbing,two-stage regrinding was carried.The result shows that the grade of molybdenum ore concentrate is 45.31%,the recovery is 65.98% and the rich ore ratio reaches 20.59% by the regrinding and scrubbing seven cleaning,the regrinding of concentrations from middling of molybdenum-sulfur separation.The regularly-concentrated material from the apparatus was as the middling products.Hence,ideal beneficiation index can be obtained with a rational mineral processing,which offers new beneficiating technology for the refractory low-grade molybdenum ore in China.

  13. Techniques of copper recovery from Mexican copper oxide ore

    Institute of Scientific and Technical Information of China (English)

    CAO Zhan-fang; ZHONG Hong; LIU Guang-yi; ZHAO Shu-juan

    2009-01-01

    Mexican copper ore is a mixed ore containing mainly copper oxide and some copper sulfide that responds well to flotation. The joint techniques of flotation and leaching were studied. The results indicate that an ore containing 19.01% copper could be obtained at a recovery ratio of 35.02% by using sodium sulfide and butyl xanthate flotation. Over 83.33% of the copper oxide can be recovered from the tailings by leaching in suitable conditions, such as 1 h stirring at a temperature around 25 ℃ with a mixing speed of 500 r/min, an H2SO4 concentration of 1.0 mol/L and a mass ratio of the ore-slurry-liquid to solid (mL/mS) of 3. The overall yield of refined ore after flotation and leaching is over 89.18% of the copper, which is much better than sole flotation or leaching. A copper product containing more than 99.9% copper was obtained by using the process: flotation-agitation leaching-solvent extraction-electro-winning.

  14. On the use of bastnasite ore as a phosphor material

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, M., E-mail: manojm@barc.gov.in; Natarajan, V.; Rajeswari, B.; Dhobale, A.R.; Godbole, S.V.

    2014-01-15

    Bastnasite ore obtained from Indian Rare Earth (IRE) was investigated for its possible use as a phosphor material. The material was characterized by X-ray diffraction (XRD), energy dispersive X-ray fluorescence (EDXRF), photoacoustic spectroscopy (PAS), photoluminescence (PL) and electron paramagnetic resonance spectroscopy (EPR) techniques. XRD studies revealed the semi processed ore to be consisting of single phase CeO{sub 2} with no other impurities. EDXRF studies revealed the presence of ‘Th’ and traces of ‘Sm’ along with ‘Ce’ in the sample. PAS studies revealed the presence of strong charge transfer from oxygen to cerium in the system. PL studies confirmed the presence of at least four trivalent rare earths, viz. Sm, Eu, Dy and Tb in the system in trace quantities. The emission spectrum and decay time data were evaluated. It was observed that the rare earth ions are situated at distorted sites in the system surrounded by defect centers. EPR studies confirmed the presence of Ce{sup 3+}in the system along with electron trapped in oxygen ion vacancies. CIE indices for the ore sample were evaluated and it was seen that the overall emission from the system was in the ‘magenta’ region of the visible spectrum. The emission intensities were also compared with that of commercial samples. -- Highlights: • Characterization of bastnasite ore as a phosphor material. • Role of RE impurities in the luminescence • CIE index of the bastnasite ore.

  15. Manual on laboratory testing for uranium ore processing

    International Nuclear Information System (INIS)

    Laboratory testing of uranium ores is an essential step in the economic evaluation of uranium occurrences and in the development of a project for the production of uranium concentrates. Although these tests represent only a small proportion of the total cost of a project, their proper planning, execution and interpretation are of crucial importance. The main purposes of this manual are to discuss the objectives of metallurgical laboratory ore testing, to show the specific role of these tests in the development of a project, and to provide practical instructions for performing the tests and for interpreting their results. Guidelines on the design of a metallurgical laboratory, on the equipment required to perform the tests and on laboratory safety are also given. This manual is part of a series of Technical Reports on uranium ore processing being prepared by the IAEA's Division of Nuclear Fuel Cycle and Waste Management. A report on the Significance of Mineralogy in the Development of Flowsheets for Processing Uranium Ores (Technical Reports Series No. 196, 1980) and an instruction manual on Methods for the Estimation of Uranium Ore Reserves (No. 255, 1985) have already been published. 17 refs, 40 figs, 17 tabs

  16. Utilisation of iron ore tailings as aggregates in concrete

    Directory of Open Access Journals (Sweden)

    Francis Atta Kuranchie

    2015-12-01

    Full Text Available Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength were tested. A controlled mix of concrete was also prepared in similar way using conventional materials and the results were compared with the tailings concrete. It was found that the iron ore tailings may be utilised for complete replacement for conventional aggregates in concrete. The iron ore tailings aggregates concrete exhibited a good mechanical strength and even in the case of compressive strength, there was an improvement of 11.56% over conventional aggregates concrete. The indirect tensile strength did not improve against the control mix due high content of fines in the tailings aggregates but showed 4.8% improvement compared with the previous study where the conventional fine aggregates was partially replaced by 20% with iron ore tailings.

  17. Existing State and Partitioning of Rare Earth on Weathered Ores

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The existing state and partitioning of rare earth (RE) on weathered ores in Longnan County (LN), Xingfeng County(XF) and Ninghua County(NH) were characterized systematically by standard geological analytical methods. It is found that RE in the weathered rare earth ores exist as four phases: (a) water soluble, (b) ion-exchangeable, (c) colloidal sediment (oxides), (d) minerals, in which mainly as ion exchangeable phase, accounting for nearly 80% of total RE,with about 20% in the form of colloid sediment phase and mineral phase, but very little as aqueous soluble phase. These rare earth partitioning were mainly chosen mid-heavy RE elements, occupying above 60%, but not equal in the four phases. The mid-heavy RE elements were primarily enriched in the ion exchangeable phase up to 40%, while the containment of cerium dioxide is below 2%. The cerium deficiency occurs in the ion exchangeable phase in weathered ore. It results from that the Ce3+ is oxidized into Ce4+ and changes into CeO2. For LN ore, the containment of Y is high in weathered ore because Y-minerals are abundant in original rock.

  18. Deformation and metamorphism of gold-sulphide lodes in the Bhukia–Jagpura gold prospect, Rajasthan: Implications for ore genesis

    Indian Academy of Sciences (India)

    S Deol; A Chattopadhyay; M Deb

    2014-02-01

    The role of polyphase deformation in controlling the emplacement of gold-quartz lodes in dilational regimes is demonstrated from the Proterozoic Bhukia–Jagpura gold prospect in south Rajasthan. Earlier researchers deciphered the gold-sulphide mineralisation event as synchronous to the second phase of deformation (D2) without convincing microstructural or metamorphic evidences. In this contribution, we correlate the deformation and metamorphic imprints in the host rocks with those in the gold-sulphide mineralised zone, and present a new interpretation for the relative timing of gold emplacement vis-á-vis deformation. The ore-forming process first involved layer-parallel influx of ore-bearing hydrothermal fluids along S1 schistosity in the host rocks, synkinematic with respect to the first phase of deformation (D1). This initial ore concentration experienced metamorphism isofacially (∼500° C at 5.3 kb) along with its host rocks during D1, and subsequently underwent extensive remobilisation, giving rise to gold-bearing silicified lodes along the hinges and axial surfaces of F2 folds during D2.

  19. 法国比利牛斯山Trimouns滑石-绿泥石矿床地质与成因%Geology and ore genesis of the Trimouns talc-chlorite ore deposit,Pyrénées,France

    Institute of Scientific and Technical Information of China (English)

    Ph de PARSEVAL; 蒋少涌; F FONTAN; 王汝成; F MARTIN; J FREEET

    2004-01-01

    位于法国比利牛斯山的nimouns矿床是世界上最大的滑石-绿泥石矿床之一.对该矿床形成的条件及滑石和绿泥石矿石的含量已较清楚.它是由不同类型的岩石通过热液交代蚀变而形成的,主要包括白云岩蚀变为滑石为主的矿石和硅铝质岩石(云母片岩和伟晶岩)蚀变为绿泥石为主的矿石.滑石矿石显示片理化结构(滑石片岩)或压实块状结构(块滑石).由伟晶岩蚀变而来的绿泥石矿石为呈绿色的球状矿体,而由云母片岩蚀变而来的绿泥石矿石呈块状或片理状、颜色为灰绿色和深灰色.本文对欧洲这个独一无二的滑石和绿泥石矿床的地质特征和成因进行了总结和讨论.流体包裹体研究表明成矿流体为高盐度(20 to30%eq.wt%NaCl)、中温(320℃)、压为为2.5kbars.磷钇矿和独居石的U-Pb定年结果表明,成矿年代为112~97Ma,成矿作用可能持续了16Ma以上.%The Trimouns deposit, in the French Pyr閚閑s, is one of the largest talc and chlorite exploitation in the world. The conditions of formation and concentration for talc and chlorite ores are now well known. The deposit consists the metasomatic alteration of various rocks, mainly dolostones altered into talc-dominant ore and silico-aluminous rocks (mica schists and pegmatites) into chlorite-dominant ore. The talc ore shows schisteous texture (talc schist) or in compact mass (steatite). The chlorite ore altered from pegmatite show green colors and ball bodies. The chlorite ores altered from mica schists are either massive or schisteous ores with graygreenish and dark gray colors. This paper summarizes the general geology and ore genesis of this exceptional talc and chlorite ore deposit in Europe. Fluid inclusion study shows high salinity of 20 to 30% eq. wt% NaCl, intermediate temperature of 320℃ and pressure of 2.5 kbars for the formation of Trimouns deposit. According to U-Pb dating on xenotime and monazite, the mineralization took

  20. Metallogeny, exploitation and environmental impact of the Mt. Amiata mercury ore district (Southern Tuscany, Italy)

    Science.gov (United States)

    Rimondi, V.; Chiarantini, L.; Lattanzi, P.; Benvenuti, M.; Beutel, M.; Colica, A.; Costagliola, P.; Di Benedetto, F.; Gabbani, G.; Gray, John E.; Pandeli, E.; Pattelli, G.; Paolieri, M.; Ruggieri, G.

    2015-01-01

    The Mt. Amiata mining district (Southern Tuscany, Italy) is a world class Hg district, with a cumulate production of more than 100,000 tonnes of Hg, mostly occurring between 1870 and 1980. The Hg mineralization at Mt. Amiata is younger than 0.3 Ma, and is directly related to shallow hydrothermal systems similar to present-day geothermal fields of the region. There is likely a continuum of Hg deposition to present day, because Hg emission from geothermal power plants is on-going. In this sense, the Mt. Amiata deposits present some analogies with “hot-spring type” deposits of western USA, although an ore deposit model for the district has not been established. Specifically, the source of Hg remains highly speculative. The mineralizing hydrothermal fluids are of low temperature, and of essentially meteoric origin.

  1. Uranium Rirang ore processing: extraction of uranium from Rirang ore digestion solution with tributyl phosphate

    International Nuclear Information System (INIS)

    Uranium is extracted from Rirang ore acid digestion solution containing rare earths. A mixture of tributyl phosphate solvent and kerosene diluent is employed. Several parameters of solvent extraction have been studied included aqueous to organic phase ratio, H2O2 reductor concentration and Tbp concentration in the solvent mixture, as well as the aqueous to organic phase ratio in the stripping process. The optimum conditions for the extraction step include the use of 25% H2O2 (v/v), one to one aqueous to organic ratio, and 40% Tbp in kerosene. The extraction recovery for U, RE, Th, and PO43- are 99%, 4%, 70%, and 30%, respectively. The stripping step optimum conditions include the use of one to five organic to aqueous phase ratio 0.24 N HNO3. and the stripping recovery for U, RE, Th, and PO43- are 84%, 80%, 72%, and 83%, respectively

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

    Science.gov (United States)

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

    2016-01-01

    simply by the evaporation of seawater to halite saturation and requires a dilution of more than two times by meteoric water. The higher K/Na values in fluid inclusions from barite suggest that the brines interacted with K-rich rocks in the basement or siliciclastic sediments in the basin. Carbonate gangue minerals (ankerite and calcite) have δ13C and δ18O values that are close to the carbonate host rock and indicate fluid equilibrium between carbonate host rocks and hydrothermal brines. The δ34S values for sphalerite and galena fall within a narrow range (1 to 10 ‰) with a bulk value of 7.5 ‰, indicating a homogeneous source of sulfur. The δ34S values of barite are also relatively homogeneous (22 ‰), with 6 ‰ higher than the δ34S of local and regional Triassic evaporites (15 ‰). The latter are believed to be the source of sulfate. Temperature of deposition together with sulfur isotope data indicate that the reduced sulfur in sulfides was derived through thermochemical sulfate reduction of Triassic sulfate via hydrocarbons produced probably from Late Cretaceous source rocks. The 87Sr/86Sr ratio in the Bou Jaber barite (0.709821 to 0.711408) together with the lead isotope values of Bou Jaber galena (206Pb/204Pb = 18.699 to 18.737;207Pb/204Pb = 15.635 to 15.708 and 208Pb/204Pb = 38.321 to 38.947) show that metals were extracted from homogeneous crustal source(s). The tectonic setting of the Bou Jaber ore deposit, the carbonate nature of the host rocks, the epigenetic style of the mineralization and the mineral associations, together with sulfur and oxygen isotope data and fluid inclusion data show that the Bou Jaber lead-zinc mineralization has the major characteristics of a salt diapir-related Mississippi Valley-type (MVT) deposit with superimposed events of fluorite and of barite deposition. Field relations are consistent with mineral deposition during the Eocene–Miocene Alpine orogeny from multiple hydrothermal events: (1) Zn

  3. 2.9-1.9 Ga paleoalterations of Archean granitic basement of the Franceville basin (Gabon)

    Science.gov (United States)

    Mouélé, Idalina Moubiya; Dudoignon, Patrick; El Albani, Abderrazak; Meunier, Alain; Boulvais, Philippe; Gauthier-Lafaye, François; Paquette, Jean-Louis; Martin, Hervé; Cuney, Michel

    2014-09-01

    The Archean granitoids in the Kiéné area, Gabon, are overlained by the Paleoproterozoic sediments of the Franceville basin (2.1 Ga). The basin is known for its high-grade uranium deposits among which some have been forming natural nuclear fission reactors. Most of the studies were dedicated to the FA-FB Paleoproterozoic sediments hosting these uranium deposits. Little is known on the Archean basement itself and specifically on the hydrous alteration events it experienced before and after the sediment deposition. The present work is focused on their petrographical, mineralogical and geochemical characterization. Dating the successive alteration events has been attempted on altered monazite crystals. Rocks in different alteration states have been sampled from eight drill cores crosscutting the Archean - Paleoproterozoic unconformity. The Archean granitoids observed in the deepest levels exhibit typical petrographical features of a propylitic alteration while they are intensely illitized up to the unconformity. The propylitic alteration is mainly pervasive but the original texture of the granitoïds is conserved in spite of the formation of new minerals: Mg-chlorite, allanite and epidote forming a typical paragenesis. The illitic alteration is much more invasive near the unconformity. The illitization process leads to the replacement of feldspars and the corrosion of quartz crysals by an illitic matrix while the ferromagnesian minerals are pseudomorphosed by a Fe-chlorite + phengite + hematite assemblage. The final fluid-rock interaction step is marked by fissural deposits of calcite and anhydrite. The δ13C isotopic data show that the fissural carbonates precipitated from diagenetic fluids enriched carbon products deriving from the maturation of organic matter. The U-Pb isotopic analyzes performed on monazite crystals have dated three distinct events: 3.0-2.9 Ga (magmatic), 2.6 Ga (propylitic alteration) and 1.9 Ga (diagenetic illitization). The calculation of

  4. Textured fluids

    OpenAIRE

    Guenther, Gerhard K.

    1995-01-01

    The rheology and development morphology of textured fluids have been investigated. The first fluid considered in this work was a liquid crystalline polymer consisting of isotropic and anisotropic solutions of poly-p-phenyleneterephthalamide (PPT) in sulfuric acid. The second textured fluid considered in this work was an immiscible polymer blend consisting of poly(ethylene terephthalate) (PET) and nylon 6,6. The role played by liquid crystalline order (LCO) and a polydomain ...

  5. Note: O-ring stack system for electron gun alignment

    International Nuclear Information System (INIS)

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications

  6. Phase transformation in suspension roasting of oolitic hematite ore

    Institute of Scientific and Technical Information of China (English)

    李艳军; 王儒; 韩跃新; 魏新超

    2015-01-01

    Suspension roasting followed by magnetic separation is a promising method to upgrade oolitic hematite ore. An oolitic hematite ore was roasted using suspension roasting technology at different temperatures. The phase transformation for iron minerals was investigated by XRD and Mossbauer spectrum, and the characteristics of roasted product were analyzed by VSM and SEM-EDS. Results indicate that the magnetic concentrate is of 58.73% Fe with iron recovery of 83.96% at 650 °C. The hematite is rapidly transformed into magnetite during the roasting with transformation ratio of 92.75% at 650 °C. Roasting temperature has a significant influence on the phase transformation of hematite to magnetite. The transformation ratio increases with increased temperature. After roasting, the magnetic susceptibility is significantly improved, while iron ore microstructure is not altered significantly.

  7. Environmental Mineralogy of the Kursk Iron Ore Deposit

    Science.gov (United States)

    Posukhova, Tatiana V.; Riakhovskaya, Sofiya K.

    The development of new technologies is one of the most effective ways to solve environmental problems related to ore-dressing. Complex mineralogical investigations are able to help in improving this process. In collaboration with researchers from the IPKON institute, we have developed an electrochemical method to improve the properties of crushed ores prepared for the wet magnetic separation. This article studies the samples before and after application of the electrochemical method. Surfaces of mineral grains investigated by the scanning electron microscopy show differences in flocculation. Measured polarization curves showed unequal electrochemical processes on surfaces of magnetite, hematite, and martite particles. X-ray analysis and Mössbauer data also confirmed the changes in compositions of the ores before and after using the electrochemical method. Magnetic properties of the studied species to be compared before and after the application of method showed relevant increase in parameters such as magnetic viscosity (Svo), breaking saturation field (Hcr), magnetic susceptibility (χ), and specific magnetization (Is).

  8. Spectral Reflectance Features of Rocks and Ores and Their Applications

    Institute of Scientific and Technical Information of China (English)

    杨柏林; 王兴理

    1991-01-01

    The spectral reflectance features of rocks and minerals are correlated with their composition,col-or,grain size and surface state.Different wall rocks,altered rocks and ores have their spectral reflectance features,which are very helpful for the explanation of remote sensing data and searching for mineral deposits by remote sensing.After the treatment of spectrum data and searching for mineral deposits by remote sensing.After the treatment of spectrum data of rocks and ores and physical and chemical parameters in the mathematical statistics,we analyzed the laboratorial spectrum dataand put forward better wave bands(520-590,650-710,730-760,770-860,1560-1760,2200 and 2300-2400nm) for distinguishing rocks and ores.

  9. Fossil bacteria in Xuanlong iron ore deposits of Hebei Province

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Discovered in Early Proterozoic Xuanlong iron ore deposits are six genera of fossil iron bacteria, i. e. sphere (coenobium of) rod-shaped (monomer) Naumanniella, ellipsoid elliptical Ochrobium, sphere spherical Siderocapsa and chain spherical Siderococcus, chain rod-shaped Leptothrix and Lieskeella, and six genera of fossil blue bacteria, namely sphere spherical Gloeocapsa, Synechocystis and Globobacter, chain spherical Anabaena and Nostoc, and constrictive septate tubular Nodularia. The biomineralized monomers and coenobia of the two categories of bacteria, together with hematite plates made up the bacteria pelletal, bacteria silky,bacteria fibrous and clasty bacteria pelletal textural lamina. The bacteria pelletal laminae combined with other bacteria laminae to make up oncolite, stromatolite and laminate. The precipitation of iron oxide was accelerated due to iron and blue bacteria cohabiting on microbial film or mat. The Xuanlong iron ore deposits are microbial binding ore deposits of ocean source.

  10. Investigation of chemical suppressants for inactivation of sulfide ores

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to investigate the effective control method of spontaneous combustion in the mining of sulfide ore deposits, This paper presents the testing results of several selected chemicals (water glass, calcium chloride, calcium oxide, magnesium oxide and their composites) as oxidation suppressants for sulfide ores. A weight increment scaling method was used to measure suppressant performance, and this method proved to be accurate, simple and convenient. Based on a large number of experiments, the test results show that four types of chemical mixtures demonstrate a good performance in reducing the oxidation rate of seven active sulfide ore samples by up to 27% to 100% during an initial 76 d period. The mixtures of water glass mixed with calcium chloride and magnesium oxide mixed with calcium chloride can also act as fire suppressants when used with fire sprinkling systems.

  11. A hybrid decision support system for iron ore supply

    Directory of Open Access Journals (Sweden)

    A. Samolejová

    2012-01-01

    Full Text Available Many European metallurgical companies are forced to import iron ore from remote destinations. For these companies it is necessary to determine the amount of iron ore that will have to be ordered and to create such a delivery schedule so that the continuous operation of blast-furnace plant is not disrupted and there is no exceedingly large stock of this raw material. The objective of this article is to design the decision support system for iron ore supply which would effi ciently reduce uncertainty and risk of that decision-making. The article proposes a hybrid intelligent system which represents a combination of diff erent artifi cial intelligence methods with dynamic simulation technique for that purpose.

  12. Calcination-Digestion-Desliming of Phosphorus Ore Bearing Rare Earth

    Institute of Scientific and Technical Information of China (English)

    Zhang Qin; Zhang Jie; Wang Jing; Qiu Yue qin

    2004-01-01

    The recoveries of phosphorus and RE of ore from Zhijin in Guizhou were studied.The influences of the calcination temperature, resident time, the digested time and water volume of the calcinating on concentrate yield by desliming were also investigated by orthogonal design.Appropriate calcination temperature is initial condition that makes carbonate mineral decomposition.The recovery of phosphorus is 83.02% and rare earth is 90.56% in phosphorus concentrate when calcined temperature is 900 ℃, other conditions include: calcined time is 30 min, digestion water volume is 300 ml, digestion time is 20 min.The results show that the pre-treatment of the ore is favorable for the separation and enrichment of rare earth from phosphorus ore, and a process of calcination-digestion-desliming was promised.

  13. Experimental Study of the Distribution of Au and Cu in Aqueous Vapor Phase at High Temperatures and Its Role on Ore-forming Transportation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ronghua; HU Shumin; ZHANG Xuetong

    2008-01-01

    This study focuses on experiments of Au and Cu dissolved in vapor phase in hydrothernmlfluids. Experiments prove that Au and Cu can re-distribute in vapor phase and liquid phase duringseparation of Au- and Cu-bearing supercriticai fluids to vapor and liquid phases. These experimentalresults can illustrate some ore geneses, where boiling phenomena of ore fluids were found. Au- and Cu-bearing NaHCO3-HCl solutions were heated up to more than 350℃ in the main vessel, and then passedthrough a phase separator in a temperature range from 250oC to 300℃, separated into vapor andliquid phases. We collected and analyzed the liquid and vapor samples separately, and found that Auand Cu dissolved and distributed in vapor phase. In some cases, the concentrations of Au and Cu invapor are higher than those in liquid phase. Those experiments are used to interpret field observationsof fluid inclusion data of some Au and Cu deposits, and demonstrate that some Au and Cu ore depositsare derived from metals transportation in vapor phase.

  14. Fluid mechanics

    CERN Document Server

    Kundu, Pijush K; Dowling, David R

    2011-01-01

    Fluid mechanics, the study of how fluids behave and interact under various forces and in various applied situations-whether in the liquid or gaseous state or both-is introduced and comprehensively covered in this widely adopted text. Revised and updated by Dr. David Dowling, Fluid Mechanics, 5e is suitable for both a first or second course in fluid mechanics at the graduate or advanced undergraduate level. Along with more than 100 new figures, the text has been reorganized and consolidated to provide a better flow and more cohesion of topics.Changes made to the

  15. Challenges facing the North American iron ore industry

    Science.gov (United States)

    Jorgenson, J.D.

    2005-01-01

    During the 20th century, the iron ore mining industries of Canada and the United States passed through several periods of transformation. The beginning of the 21st century has seen yet another period of transformation, with the economic failure of a number of steel companies, the acquisition of their facilities by more viable steelmakers, and the consolidation of control within the North American iron ore industry. Changes in Canadian and United States iron ore production and the market control structure involved are analysed. The consolidation of ownership, formation of foreign joint ventures within Nordi America, planned divestitures of upstream activities by steelmakers, and industry changes made to ensure availability of feedstocks will be reviewed. The ttaditional isolation of the Canadian and United States iron ore operations and their strong linkage to downstream steel production will be discussed in the context of a changing global economy. Management-labour conflicts that have taken place and agreements made during 2000 through 2004 will be discussed in the context of the economic environment leading up to these agreements. Cooperative agreements between competing Canadian and United States companies to resolve client needs in processing and blending will be examined. A joint industry-government project designed to use new technology to produce direct reduced iron nuggets of 96 - 98 per cent iron content using non-coking coals will also be assessed. Changes in iron ore transportation methods, ownership and infrastructure will be reviewed for both rail and inland waterway transport between Canadian and United States companies. A brief analysis of social and environmental issues relating to sustainable development of the Canadian-United States iron ore industry will be included.

  16. Isolation and identification of iron ore-solubilising fungus

    Directory of Open Access Journals (Sweden)

    Damase Khasa

    2010-09-01

    Full Text Available Potential mineral-solubilising fungi were successfully isolated from the surfaces of iron ore minerals. Four isolates were obtained and identified by molecular and phylogenetic methods as close relatives of three different genera, namely Penicillium (for isolate FO, Alternaria (for isolates SFC2 and KFC1 and Epicoccum (for isolate SFC2B. The use of tricalcium phosphate (Ca3(PO42in phosphate-solubilising experiments confirmed isolate FO as the only phosphate solubiliser among the isolated fungi. The bioleaching capabilities of both the fungus and its spent liquid medium were tested and compared using two types of iron ore materials, conglomerate and shale, from the Sishen Iron Ore Mine as sources of potassium (K and phosphorus (P. The spent liquid medium removed more K (a maximum of 32.94% removal, from conglomerate, than the fungus (a maximum of 21.36% removal, from shale. However, the fungus removed more P (a maximum of 58.33% removal, from conglomerate than the spent liquid medium (a maximum of 29.25% removal, from conglomerate. The results also indicated a potential relationship between the removal of K or P and the production of organic acids by the fungus. A high production of gluconic acid could be related to the ability of the fungus to reduce K and P. Acetic, citric and maleic acids were also produced by the fungus, but in lower quantities. In addition, particle size and iron ore type were also shown to have significant effects on the removal of potassium and phosphorus from the iron ore minerals. We therefore conclude that the spent liquid medium from the fungal isolate FO can potentially be used for biobeneficiation of iron ore minerals.

  17. 库车克拉2气田多期油气充注的古流体证据%Palaeo-fluid evidence for the multi-stage hydrocarbon charges in Kela-2 gas field, Kuqa foreland basin, Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    鲁雪松; 刘可禹; 卓勤功; 赵孟军; 柳少波; 方世虎

    2012-01-01

    The multi-stage hydrocarbon charge process of Kela-2 gas field in the Kuqa foreland basin was studied from the perspective of palaeo-fluid evidence by the analyses of fluid inclusions, fluorescence spectroscopy, FE-SEM (field emission scanning electron microscopy) observation, core micro-CT scanning, and hydrocarbon geochemistry. The result shows that the Kela-2 gas field has experienced three periods of hydrocarbon charge process: (1) charged with oil at the early-middle period of the Miocence (N1), (2) charged with high maturity oil & gas at the sedimentary period of the Pliocence Kuqa Formation (N2) and then destroyed by intense tectonic compression, and (3) charged with high-over maturity coal-derived gas since the Quaternary. The widely distributed residual dry bitumen, the occurrence of gas-liquid two-phase hydrocarbon inclusions, the residual oils observed in the nanopores, the higher QGF and QGF-E index, and the higher Si, S2 values of rock pyrolysis detected in both current gas zone and water zone, are the evidence of early oil charges. The residual dry bitumen, the occurrence of gas-oil-solid (bitumen) three-phase hydrocarbon inclusions, the loss of light n-alkanes and the relatively high content of aromatic hydrocarbons in the condense oil, and the abnormally high content of diamondoid hydrocarbons, are the strong evidence of gas flushing and deasphalting.%对库车前陆盆地克拉2气田储集层进行流体包裹体分析、荧光光谱分析、场发射扫描电镜观察、岩心显微CT扫描及油气地球化学分析,从古流体证据的角度综合研究克拉2气田多阶段油气充注过程.克拉2气田经历了中新世早中期(N1)原油充注、上新世库车组沉积期(N2)高成熟油气充注与破坏、第四系(Q1以来)高一过成熟煤成气充注的3期成藏过程.储集层中广泛分布的残余干沥青、较发育的气液两相烃包裹体、纳米孔中的残余油、现今气层和水层中较高的颗粒(抽提物)荧

  18. Analysis and Data Mining of Lead-Zinc Ore Data

    OpenAIRE

    Zanev, Vladimir; Topalov, Stanislav; Christov, Veselin

    2013-01-01

    This paper presents the results of our data mining study of Pb-Zn (lead-zinc) ore assay records from a mine enterprise in Bulgaria. We examined the dataset, cleaned outliers, visualized the data, and created dataset statistics. A Pb-Zn cluster data mining model was created for segmentation and prediction of Pb-Zn ore assay data. The Pb-Zn cluster data model consists of five clusters and DMX queries. We analyzed the Pb-Zn cluster content, size, structure, and characteristics. The set of the DM...

  19. Mining remittances corresponding to metalliferous ores: regulation and budget impact

    Directory of Open Access Journals (Sweden)

    N. Asaloș

    2016-04-01

    Full Text Available Economic statistics and forecasting show that Romania has a very favourable potential as far as the metalliferous ores are concerned. As these are owned by the state, once they are allowed to be exploited, they generate considerable amounts for the consolidated public budget. The present paper is meant to conduct a synthetic analysis on the topic of mining remittances from an economic perspective, by considering the juridical framework of capitalizing deposits of ferrous and non-ferrous ores, correlated with the general regulations concerning property and the specific existing regulations of the EU and of the countries that have experience and potential in the mining sector.

  20. A novel optical granulometry algorithm for ore particles

    Directory of Open Access Journals (Sweden)

    Junhao Y.

    2010-01-01

    Full Text Available This paper proposes a novel algorithm to detect the particle size distribution of ores with irregular shapes and dim edges. This optical granulometry algorithm is particularly suitable for blast furnace process control, so its result can be used directly as a reliable basis for control system dynamics optimization. The paper explains the algorithm and its concept, as well as its method, which consists of five steps to detect ore granularity and distribution. A series of comparative experiments under industrial environments proved that this novel algorithm, compared with conventional ones, improves the accuracy of granulometry.

  1. Bioleaching of copper oxide ore by Pseudomonas aeruginosa

    Science.gov (United States)

    Shabani, M. A.; Irannajad, M.; Azadmehr, A. R.; Meshkini, M.

    2013-12-01

    Bioleaching is an environmentally friendly method for extraction of metal from ores. In this study, bioleaching of copper oxide ore by Pseudomonas aeruginosa was investigated. Pseudomonas aeruginosa is a heterotrophic bacterium that can produce various organic acids in an appropriate culture medium, and these acids can operate as leaching agents. The parameters, such as particle size, glucose percentage in the culture medium, bioleaching time, and solid/liquid ratio were optimized. Optimum bioleaching conditions were found as follows: particle size of 150-177 μm, glucose percentage of 6%, bioleaching time of 8 d, and solid/liquid ratio of 1:80. Under these conditions, 53% of copper was extracted.

  2. Rotary hearth furnace technologies for iron ore and recycling applications

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, H.; Kopfle, J.; McClelland, J.; Ripke, J.

    2008-07-01

    Midrex Technologies and Kobe Steel offer the FASTMET, FASTMELT, and ITmk3 Technologies for processing iron ore and iron-containing by-products to produce DRI and pig iron products. These processes offer steelmakers methods for economically producing high quality iron products and recovering valuable mineral resources using fine ores, by-products, and coal. Several commercial FASTMET Plants have been operating successfully for a number of years, confirming the basic process concept. A number of new projects are under development worldwide for the three technologies. This paper provides technical details of the processes, reviews promising applications, and discusses current commercial developments.

  3. Utilisation of iron ore tailings as aggregates in concrete

    OpenAIRE

    Francis Atta Kuranchie; Sanjay Kumar Shukla; Daryoush Habibi; Alireza Mohyeddin

    2015-01-01

    Sustainable handling of iron ore tailings is of prime concern to all stakeholders who are into iron ore mining. This study seeks to add value to the tailings by utilising them as a replacement for aggregates in concrete. A concrete mix of grade 40 MPa was prepared in the laboratory with water–cement ratio of 0.5. The concrete were cured for 1, 2, 3, 7, 14 and 28 days. The properties of the concrete such as workability, durability, density, compressive strength and indirect tensile strength we...

  4. Occurrence and emplacement of chromite ores in Sindhudurg district, Maharashtra, India

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; Babu, E.V.S.S.K.; Mislankar, P.G.; Gujar, A.R.; Ambre, N.V.; Loveson, V.J.

    In the present study, the occurrence and emplacement of chromite ore deposits from two abandoned mines (Kankavali (Janoli) and Wagda) in the Sindhudurg district of Maharashtra, India are presented. These ores, that occurred as lenses...

  5. A study of the distribution of rare-metals in kuroko-type ore

    Energy Technology Data Exchange (ETDEWEB)

    Murao, S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience]|[Geological Survey of Japan, Tsukuba, Ibaraki (Japan); Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    We have performed PIXE analysis of kuroko-type ore from the JADE hydrothermal site of the Okinawa Trough, Japan using the proton microprobe (PIXEPROBE). We analysed five kinds of ores dredged from the sea floor: (I) barite ore with small sulfide dissemination; (2) sphalerite-pyrite chimney; (3) pyrite ore; (4) sulfide veinlets in strongly altered rock; and (5) pyrite megacrystals in strongly altered rock. The analyses revealed that the trace element distribution is regulated by the occurrence mode of the ore, and within each ore, by the crystal structure. The distribution suggests that the hydrothermal system for kuroko ore formation is quite heterogeneous and its chemistry is controlled by local factors such as difference in temperature, and that in-situ PIXE analyses are essential for effective beneficiation strategy for the rare-metals from kuroko-type ore. (authors). 10 refs., 1 tab.

  6. Geochemical discrimination of the geotectonic environment of basaltic-andesitic volcanic rocks associated with the Laochang polymetallic ore deposit at Lancang, Yunnan

    Institute of Scientific and Technical Information of China (English)

    GAO Jianguo

    2006-01-01

    The Laochang polymetallic ore deposit at Lancang is one of the well known ancient ore deposits associated with volcanic rocks in the Sanjiang (Tri-river) region of Southwest China. Volcanic rocks are dominated by alkali basalt and trachyte basalt. There has long been a controversy on the environment of formation of basalts. Some scholars hold that the basalts were formed in a continental environment, some thought they were formed in an oceanic environment and others considered that the basalts were emplaced in a back-arc basin. This study focuses on the geochemical characteristics of the basalts on the basis of their major elements, REEs and trace elements. At the same time, strongly incompatible elements such as Ta, Th and Hf and their ratios were used to differentiate the geotectonic settings of basalts. The results showed that the basalts in the region studied were formed in a continental rift environment.

  7. Fluid Dynamics

    DEFF Research Database (Denmark)

    Brorsen, Michael

    These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University.......These lecture notes are intended mainly for the 7th semester course "Fluid Dynamics" offered by the Study Committee on Civil Engineering, Aalborg University....

  8. Pegmatite Fluids of Different Origins and Their Implications for Mineralization

    Institute of Scientific and Technical Information of China (English)

    李兆麟; 杨荣勇; 等

    1999-01-01

    Characteristics of ore-forming fluids as inferred from detailed studies of inclusions indicate that pegmatites may have different origins.For example,the granitic pegmatite at Mufushan is originated from magma differentiation at 1100-200℃,while the No.3 Pegmatite Vein in Xinjiang may owe its origin to a pegmatitic magma produced via metamorphic anatexis at 1140-200℃.Pegmatite fluids of the above two types are a melt-liquid system and may evolve into a solid-melt or solid-liquid system that would have a critical bearing on metasomatism and intergranular solutions.The Minxi pegmatite,on the oter hand,resulted from metamorphic differentiation,with its fluid(formed at 400-180℃)exhibiting many features of metamorphism.Pegmatites of different origins are distributed in tectonic units of different characters and are different bot in the nature of ore-foming fluid and in the source of ore-metals.This concept of polygene launches a challenge to the traditional belief that pegmatite is exclusively originated from magma differentiation and may be helphfou for the establishment of a new theory of pegmatite genesis.

  9. Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield

    Science.gov (United States)

    Kalashnyk, Anna

    2015-04-01

    ,32-62,17%, MgO = 7,3-12,5%) allow us to estimate the depth of generation of kimberlite magmas more than 170-200 km. Ilmenites show two groups according to MgO, Cr2O3 and TiO2 content. Reconstructions of the mantle sections show also two intervals of pressures divided at 4.5 GPa, the upper part is highly metasomatized This high degree metasomatism is determined for almost all mantle columns. It is suggested that large-scale of uranium-bearing mantle fluids may be associated with the ancient degasation during the subduction which is highly enriched in U component . Analysis of the reasons for the marked association kimberlitic dykes and major industrial uranium deposits in carbonate-sodium metasomatic in the UkrSh led to the conclusion that hydrothermal uranium deposits are confined to the supply mantle fluid systems of mantle fault zones exercising brings sodium carbonate solutions enriched uranium from mantle sources. References: 1. Kalashnik A.A. New prognostic-evaluation criteria in technology prognosis of forming industrial endogenous uranium deposits of the Ukrainian Shield, 2014. Scientific proceedings of UkrSGRI, № 2, p. 27-54 (in Russian) 2. Stepanjuk L.M., Bondarenko S.V., Somka V.O. and other, 2012. Source of uranium and uranium-bearing sodium albitites for example of Dokuchaievskogo field of the Ingulsky megablock of the UkrSh: Abstracts of scientific conference "Theoretical issues and research practice metasomatic rocks and ores" (Kyiv, 14-16 March 2012), IGMOF, p.78-80. (in Ukrainian)

  10. Genesis and formation conditions of deposits in the unique Strel'tsovka Molybdenum-Uranium ore field: New mineralogical, geochemical, and physicochemical evidence

    Science.gov (United States)

    Aleshin, A. P.; Velichkin, V. I.; Krylova, T. L.

    2007-10-01

    The ambiguity of genetic interpretations of uranium ore formation at Mo-U deposits of the Strel’tsovka ore field led us to perform additional geochemical, mineralogical, and thermobarogeochemical studies. As a result, it has been established that closely related U and F were progressively gained in the Late Mesozoic volcanic rocks from the older basic volcanics (170 Ma) to the younger silicic igneous rocks (140 Ma). The Early Cretaceous postmagmatic hydrothermal epoch (140-125 Ma) is subdivided into preore, uranium ore, and first and second postore stages. The primary brannerite-pitchblende ore was formed in association with fluorite. At the first postore stage, this assemblage was replaced by a U-Si metagel, which was previously identified as coffinite. The metagel shows a wide compositional variation; its fine structure has been studied. The preore metasomatic alteration and related veined mineralization were formed under the effect of sodium (bicarbonate)-chloride solution at a temperature of 250-200°C. The uranium ore formation began with albitization and hematitization of rocks affected by supercritical fluid at 530-500°C; brannerite and pitchblende precipitated at 350-300°C. The chondrite-normalized REE patterns of pitchblende hosted in trachybasalt, trachydacite, and granite demonstrate a pronounced Sm-Nd discontinuity and a statistically significant tetrad effect of W type. These attributes were not established in REE patterns of rhyolites derived from the upper crustal magma chamber. This circumstance and a chronological gap of 5 Ma between silicic volcanism and ore formation do not allow us to suggest that uranium was derived from this magma chamber. According to the proposed model, the evolved silicic Li-F magma was a source of uranium. U4+, together with REE, was fractionated into the fluid phase as complex fluoride compounds. The uranium mineralization was deposited at a temperature barrier. It is suggested that hydromica alteration and the

  11. Research on Fluid Inclusions of the Yinshan Polymetallic Deposit,Jiangxi Province,China

    Institute of Scientific and Technical Information of China (English)

    张德会; 刘伟

    1999-01-01

    In this paper some new advances in the study of fluid inclusions of the Yinshan deposit in Jiangxi Province,China,are presented.The fluid inclusions of the deposit can be divided into four types:1) gas-rich inclusions;2)liquid-rich inclusions;3)salt-saturated H2O inclusions;and 4)single-phase or multiphase CO2-rich inclusions.Homogenization temperatures of the fluid inclusions range from 100 to 520℃,aminly in the range 120-400℃.The daughter crystal-bearing multiphase inclusions present in quartz porphyries(including Nos.13 and 4 dikes)have been observed.In ore veins,some daughter crystal-bearing multiphase inclusions have been observed.too.On the basis of the results of fluid inclusion research,the authors suggest that the ore-forming fluid must have a close genetic relation to magmatic hydrothermal solution.The ore-forming fluid was dominantly originated from the depth and the mixing of magmatic solution with meteoric water was enhanced during ascending of the fluid,accompanying immiscibility and boiling of fluid.Teher may be a conceales igneous body at the depth of the Yinshan deposity,which furnishes the scientific basis for metallogenic prognosis at th depth of the Yinshan deposit.

  12. A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia

    Science.gov (United States)

    Ingham, Edwina S.; Cook, Nigel J.; Cliff, John; Ciobanu, Cristiana L.; Huddleston, Adam

    2014-01-01

    The common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at Pepegoona, Pepegoona West and Pannikan, Lake Eyre Basin, South Australia. Combined chemical, isotopic and microstructural analysis of pyrite indicates variation in fluid composition, sulfur source and precipitation conditions during a protracted mineralization event. The results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low-temperature hydrothermal systems. In-situ micrometer-scale sulfur isotope analyses of pyrite demonstrated broad-scale isotopic heterogeneity (δ34S = -43.9 to +32.4‰VCDT), indicative of complex, multi-faceted pyrite evolution, and sulfur derived from more than a single source. Preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation. Authigenic pyrite underwent prolonged evolution and recrystallization, evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra. Secondary hydrothermal pyrite commonly displays hyper-enrichment of several trace elements (Mn, Co, Ni, As, Se, Mo, Sb, W and Tl) in ore-bearing horizons. Hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types. Irregular variation in δ34S, coupled with oscillatory trace element zonation in secondary pyrite, is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization. A late-stage oxidizing fluid may have mobilized selenium from pre-existing pyrite. Subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re-crystallization and precipitation of selenium as native selenium. These results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at Beverley North. Insights into

  13. Tectonic environment, geochemistry and petrology of the Tromsøysound iron ore

    OpenAIRE

    Pettersen, Eirik

    2013-01-01

    The geochemistry, mineralogy and associated basic rocks of the Tromsøysound iron ore field was studied for this thesis. The iron ore field is located in the Tromsø Nappe an ultra-high-pressure terrain in Troms, Northern-Norway, and has undergone some partial melting and metasomatism. The ore mineral is magnetite. The tectonic environment is investigated but inconclusive.

  14. 197Au Moessbauer study of gold ores, mattes, roaster products, and gold minerals

    International Nuclear Information System (INIS)

    The chemical state of gold in gold ores, mattes and roaster products has been studied by 197Au Moessbauer spectroscopy. Gold minerals were studied in order to provide reference data for the ore spectra. 57Fe Moessbauer spectroscopy was used to monitor the iron-compounds always present in gold ores and to follow their transformations caused by smelting and roasting. (orig.)

  15. 40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

    Science.gov (United States)

    2010-07-01

    ... uranium, radium and vanadium ores subcategory. 440.30 Section 440.30 Protection of Environment... SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory § 440.30 Applicability; description of the uranium, radium and vanadium ores subcategory. The provisions of this subpart C are applicable...

  16. Technological pretreatment of the synchysite non-oxidized ore

    Science.gov (United States)

    Munkhtsetseg, B.; Burmaa, G.

    2013-06-01

    Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

  17. Nonlinear Effects of Laser Surface Modification of Ore Minerals

    Directory of Open Access Journals (Sweden)

    N.A. Leonenko

    2015-12-01

    Full Text Available The effect of continuous laser radiation on complex ore minerals objects containing gold, not extracted by monerd methods was investigated. It was established the formation of different structural surfaces of gold, revealed general patterns of sintering and concentration of sub-micron gold.

  18. Shale-oil-recovery systems incorporating ore beneficiation. Final report.

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, M.A.; Klumpar, I.V.; Peterson, C.R.; Ring, T.A.

    1982-10-01

    This study analyzed the recovery of oil from oil shale by use of proposed systems which incorporate beneficiation of the shale ore (that is concentration of the kerogen before the oil-recovery step). The objective was to identify systems which could be more attractive than conventional surface retorting of ore. No experimental work was carried out. The systems analyzed consisted of beneficiation methods which could increase kerogen concentrations by at least four-fold. Potentially attractive low-enrichment methods such as density separation were not examined. The technical alternatives considered were bounded by the secondary crusher as input and raw shale oil as output. A sequence of ball milling, froth flotation, and retorting concentrate is not attractive for Western shales compared to conventional ore retorting; transporting the concentrate to another location for retorting reduces air emissions in the ore region but cost reduction is questionable. The high capital and energy cost s results largely from the ball milling step which is very inefficient. Major improvements in comminution seem achievable through research and such improvements, plus confirmation of other assumptions, could make high-enrichment beneficiation competitive with conventional processing. 27 figures, 23 tables.

  19. Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

    Science.gov (United States)

    Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

    2016-10-01

    With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

  20. Processing of domestic antimonite low grade ore by flotation

    OpenAIRE

    Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2003-01-01

    These investigations have developed an effective flotation method to recover antimony metal. In this paper will be shown bench-scale laboratory investigations for the possibility of th antimonite recovery from the domestic antimonite ore. The otimization of the technological process in these laboratory investigations provide the bulk antimonite and operating conditions.

  1. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James

    2013-08-01

    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  2. Carbothermal Reductive Upgrading of a Bauxite Ore Using Microwave Radiation

    Science.gov (United States)

    Lu, T.; Pickles, C. A.; Kelebek, S.

    2012-04-01

    The utilization of microwave radiation as the energy source for the carbothermal reductive upgrading of a bauxite ore was investigated. The bauxite ore was mechanically mixed with carbon and reacted in a quartz crucible in a multimode cavity. The iron oxide in the bauxite ore was reduced to magnetite and/or iron and the magnetic fraction was separated using a Davis Tube Tester. Three experimental arrangements were utilized: (i) microwaving of the mixture, (ii) microwaving of the mixture plus charcoal layers under ambient conditions and (iii) microwaving of the mixture plus charcoal layers in argon. The utilization of the charcoal layers resulted in more uniform heating of the sample. The effects of irradiation time, sample mass and incident power on the mass of the magnetic fraction were determined. Both the iron and the aluminum contents of the magnetic fraction were measured and using these values, the iron removal from the bauxite ore and the alumina recovery in the non-magnetic fraction were calculated. It was shown that under mildly reducing conditions, almost half of the iron could be removed as magnetite. However, the formation of hercynite limited the iron separation as magnetite and higher iron removals could only be achieved through the formation of metallic iron under more highly reducing conditions.

  3. Foetor ex ore und Halitosis. Was steckt hinter dem Mundgeruch?

    OpenAIRE

    Imfeld, T

    2009-01-01

    Rund jede vierte Person hat Mundgeruch. Dabei muss zwischen Foetor ex ore (90%, nur im Mundatem perzeptierbar) und Halitosis (10%, im Mund- und/oder Nasenatem feststellbar) unterschieden werden. Eine entsprechende Differentialdiagnose ist Voraussetzung für die Kausaltherapie. Prophylaxe und Therapie basieren auf der mechanischen und chemischen Reduktion der Erreger.

  4. Thermal investigations of direct iron ore reduction with coal

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gui-su [Niksa Energy Associates, 1745 Terrace Drive, Belmont, CA 94002 (United States); Strezov, Vladimir [Newbolds Applied Research, The University of Newcastle, Cnr Frith and Gavey Sts, Mayfield, NSW 2304 (Australia); Lucas, John A. [Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, University Drive, Callaghan 2308, NSW (Australia); Wibberley, Louis J. [BHP Billiton Newcastle Technology Centre, Off Vale Street, Shortland 2307, NSW (Australia)

    2004-02-09

    In this paper, fundamental mechanisms for iron ore reduction in coal-ore mixtures have been investigated using several advanced experimental techniques. Firstly, the thermal properties of coal-ore mixtures were studied and apparent specific heat of coal-ore mixtures against temperature was obtained at a heating rate of 10C/min. Several exothermic and endothermic peaks were observed which were related to the decomposition reactions and reduction. The flue gases from the mixture were analysed using a mass spectrometer. Secondly, the X-ray diffraction (XRD) and the iron phase analytical techniques were applied to identify the iron phase changes with the temperature. It has been found that coal devolatilisation and iron oxides reduction occur simultaneously during the heating of the mixture. H{sub 2} and CO gases produced from coal devolatilisation and char gasification were responsible for the reduction of iron oxides at these temperatures. Iron oxides undergo step-wise reduction over the whole process. The results in this work provide a fundamental understanding for the direct reduced ironmaking processes.

  5. Reduction Mechanism of Chromite Ore in Blast Furnace

    Institute of Scientific and Technical Information of China (English)

    LI Yi-wei; DING Wei-zhong; LU Xiong-gang; XU Kuang-di

    2004-01-01

    The structural changes and reduction degree of chromite ore in blast furnace were studied by optical micrograph analysis, scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDXA). The smelting reduction mechanism of chromite in blast furnace was primarily discussed.

  6. Radiation monitoring in the mining and milling of radioactive ores

    Interna