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1.
煤系砂岩裂隙水是煤矿重要的充水水源之一,以淮北煤田桃园煤矿二叠纪煤系为研究对象,在分析该矿水害注浆治理以来煤系水水化学特征的基础上,阐明了地下水水文地球化学作用机理及其控制因素。结果表明:注浆治理期间,煤系水中主要阳离子为Na+,主要阴离子为SO42-;阳离子质量浓度由大到小为Na+、Ca2+、Mg2+,阴离子质量浓度由大到小为SO42-、HCO3-、Cl-;通过Durov水化学图分析,注浆治理期间煤系水化学类型以Na-SO4和Na-HCO3为主;煤系水中存在黄铁矿氧化或碳酸盐、硫酸盐溶解作用,并伴随着一定程度的阳离子交换作用与脱硫酸作用,特别是在注浆治理工程实施期间,阳离子交换作用增强;大型突水、注浆治理防治水工程、地质构造背景及采矿活动等均不同程度地影响了煤系水水岩作用,且随注浆治理范围增大,影响程度增大。该研究成果对于煤矿涌（突）水水源识别及水害防治具有重要意义,为类似条件下的其他煤矿（区）在突水或注浆治理扰动下的地下水水文地球化学研究及应用提供参考。   相似文献   

2.
Abstract. Fluid inclusion and oxygen isotope studies are performed to obtain temperatures and oxygen isotopic compositions of hydrothermal fluids for the vein-type tungsten-copper deposit at Takatori in Ibaraki Prefecture, Japan. Temperatures of the hydrothermal fluids are calculated from fluid inclusion data. The calculation incorporates the effects of the salinity, gas concentration, and fluid pressure. The fluid temperatures range from 370 to 460C. For these calculations, this study obtains a density equation for H2O-NaCl-CO2 solution at the vapor-liquid two-phase boundary. Then the present study combines the obtained equation with the equation of state by Bowers and Helgeson (1983).
The fluid temperatures determined in this study are applied to the calculation of oxygen isotopic compositions of the hydrothermal fluids. The calculation of the oxygen isotopic compositions is based on the oxygen isotope analyses of vein quartz. The oxygen isotopic compositions of vein quartz range from +13.5 to +14.4 % relative to SMOW. Then, the oxygen isotopic compositions of the hydrothermal fluids in equilibrium with the vein quartz are calculated to be from +9.7 to +10.5 %. These δ18Ofluid values agree with those of magmatic fluids derived from the ilmenite-series granitic rock, which is related to the mineralization. Keywords: Takatori tungsten-copper deposit, fluid inclusion, oxygen isotope, vein quartz, H2O-NaCl-CO2 solution, density  相似文献   

3.
罗河铁矿水文地球化学特征及成因   总被引：2，自引：0，他引：2       下载免费PDF全文
龚星  陈植华  罗朝晖 《地球科学》2014,39(3):293-302
作为庐枞盆地较早开展勘探工作的罗河铁矿, 矿区揭露的地下水可分为潜水和承压水2类, 潜水表现为弱碱性HCO3--Ca+·Mg2+型水; 区域构造和凝灰岩阻隔了潜水和承压水的水力联系, 承压水以SO42--Ca2+型微咸温水为主, 水化学成分不受外界因素变化影响.离子比例系数和相关性分析说明承压水中主要水化学反应包括硫酸盐矿物溶解和阳离子交换.PHREEQC反向模拟SO42--Ca2+型承压水的成因主要是砖桥组下段次生石英岩中大量硬石膏、石英和水云母的原位溶解; 与此同时, 地下水中沉淀生成了方解石和绿泥石, 石膏溶解的Ca2+离子吸附交换粘土矿物中的Na+离子, 少量黄铁矿还发生了氧化还原反应.分析结果验证了罗河铁矿深部地下水相对封闭, 补给有限, 以静储量为主.   相似文献   

4.
在分析南极乔治王岛冰帽大冰穹顶部降水和成冰条件的基础上,利用冰芯上部层物理特征参数确定的5个年层及其附近气象站相应的降水记录,结合多年降水资料将大冰穹45m冰芯划分为15个年层.应用此年层剖面,证实了微粒含量的两个异常峰值分别对应于1987年Deception岛和1980年的SealNunataks两次火山喷发.乔治王岛冰帽属于温性冰帽,大、小冰穹冰芯阴阳离子受沉积后融水渗浸淋溶作用的影响.对冰芯阴阳离子的淋溶次序分析显示,大冰穹为SO42->Mg2+>Ca2+>K+>Cl->Na+>NO3->Br-,而小冰穹为Mg2+>Ca2+>SO42->K+>Cl->Br->Na+.  相似文献   

5.
Abstract: In order to know the cause of the high δ34S values of the Korean ore deposits (Ishihara et al., 2000), Geumseong molybdenum skarn deposit and related Jurassic granitoids and Cambro-Ordovician carbonates were selected for the δ34S analyses. Two sulfide samples occurring in hydrothermal veins in fresh granitoids quarry at Songhaksan yielded δ34S values of +6.9 and +8.8 permil. These are slightly higher than +5.3 permil δ34S of the averaged rock sulfides for the Jurassic Daebo granitoids. Pyrite and molybdenite from the Geumseong deposit vary from +8.6 to +11.5 permil (average + 10.7 permil). The intruded carbonates contain very low amount of SSS (structurally substituted sulfate) as 2.9 to 8.1 ppm with high δ34S values between +28.8 and + 40.0 permil, and sulfides sulfur of 52 to 779 ppm with variable δ34S values between +3.2 and +22.5 per–mil. It is concluded that sulfur of the host carbonates was extracted and migrated into the skarn deposit at the time of the granitoid intrusion and the related hydrothermal convection, on the basis of the location of the skarn deposit occurring between the carbonates and Jurassic granitoids, and of very low contents of SSS sulfur in the carbonates. A part of SSS possibly contaminated into the Jurassic granite.  相似文献   

6.
Abstract. In order to know the behaviors of radioactive elements such as cesium and strontium during a hydrothermal alteration of borosilicate glass of radioactive waste, some alumino-borosilicate glasses belonging to the systems Na2O-Al2O3-B2O3-SiO2-SrO, Na2O-Al2O3-B2O3-SiO2-Cs2O and Na2O-Al2-O3-B2O3-SiO2-SrO-Cs2O have been treated hydrothermally at 200C under a vapor pressure of 1.54 MPa. The result shows that all glasses are changed into crystalline phases with running time up to 60 days, and that analcime-type zeolite is formed as a major product. The formed zeolite is shown to contain cesium and/or strontium. Considering the fact that natural zeolite occurs in wide physicochemical conditions including hydrothermal one, the analcime-type zeolite is expected to fix stably the radioactive elements in the disposal site. Since aluminum is necessary for the formation of the analcime-type zeolite, the waste glass should have aluminum as one of major components.  相似文献   

7.
Liqiang Yang    Jun Deng    Chunying Guo    Jing Zhang    Shaoqing Jiang    Bangfei Gao    Qingjie Gong    Qingfei Wang 《Resource Geology》2009,59(2):181-193
The Dayingezhuang gold deposit is located in the central part of the Zhaoping Fault Zone, which is one of the most important gold-hosting faults in the Jiaodong gold province of China. Dayingezhuang is a typical large-scale shear zone-hosted disseminated gold deposit with superimposed silver mineralization. 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 silver mineralization. Microthermometry data of FI indicated that ore-forming fluids are characterized by low salinity and low density. Homogenization pressures of FI are estimated at 20 × 105–220 × 105 Pa. The change in ore-forming fluids from K2SO4 type to NaCl type indicates the superposition of two hydrothermal mineralizing events. Ore-forming fluids were dominated by magmatic components in the early mineralization period, and affected by meteoric waters in the late period. Gold may have been transported as Au-S or Au-Cl complexes, whereas silver was transported as Ag-Cl complexes. Early fluid boiling and later fluid mixing are thought to be two of the main factors causing the deposition and superimposing of gold and silver to form the large deposit.  相似文献   

8.
A ternary solid solution model for omphacite with the end-members jadeite (NaAlSi2O6), diopside (CaMgSi2O6) and hedenbergite (CaFeSi2O6) was derived from experimental data from the literature. The subregular solution model, fitted by linear programming, is best suited to omphacites with very little aegirine component in common eclogites. Applying this solution model to the calculation of equilibrium phase diagrams of eclogites from the Adula nappe (Central Alps, Switzerland) results in large stability fields for common eclogite assemblages (garnet+omphacite+quartz+H2O±kyanite). Within this field the compositions of garnet and omphacite show very little variation. A precise determination of the peak-pressure and temperature is not possible. The occurrence of amphibole, overgrowing the peak-pressure assemblage in fresh eclogite, suggests retrograde re-equilibration, still under eclogite facies conditions. The computation of isopleths for garnet and pyroxene end-members allows the estimation of the pressure and temperature conditions of this re-equilibration event (19–21  kbar, c .  700 °C).  相似文献   

9.
Abstract: The sulfur isotopic ratios (δ34S) of ore minerals from the Toyoha deposit, Hokkaido, one of the largest Pb–Zn–Ag polymetallic vein-type deposits in Japan, were studied. More than 90% of the δ34S values of the studied sulfide minerals collected from the Toyoha deposit range from +5 to +9%, with an average of approximately +7% irrespective of the mineral species, veins, elevations, depth, mineralization stages and mineral assemblages. Relatively uniform δ34S values obtained in this study suggest that the reduced aqueous sulfur species predominated over the oxidized sulfur in the ore solution throughout the mineralization stages. Thus, the source of sulfur for the ore sulfides is postulated to be magmatic.
The temperature obtained from the fluid inclusion study and the temperature of the sulfur isotopic geothermometer are not consistent. This suggests that each mineral precipitated under disequilibrated conditions with respect to the sulfur isotope.
The change in redox conditions presumably encountered between the mineralization stages did not account for the isotopic fluctuations since the isotopic exchanges between the oxidized and reduced aqueous sulfurs are much slower than the rate of oxidation of the ore solution.  相似文献   

10.
Abstract. The Cibaliung deposit is a low-sulfidation type epithermal gold deposit situated about 70 km west of the Bayah dome complex. The gold-bearing quartz veins are hosted by basaltic andesite of the Honje Formation, which is comparable to the host rock of gold deposits at the Bayah dome complex.
In order to clarify the timing of the mineralization and the volcanism at the Cibaliung area, two radiometric dating methods were applied. First, 40Ar/39Ar dating was conducted on six adularia samples to elucidate the age of mineralization. Second, K-Ar method was applied to two samples of the host rock, andesite and the Cibaliung tuff, in order to reveal the timing of volcanism.
The 40Ar/39Ar dating determined mineralization ages in the range from 11.18 to 10.65 Ma while the K-Ar dating indicated the age of the andesite and the Cibaliung tuff to be 11.4±0.8 Ma and 4.9±0.6 Ma, respectively. These results imply that the epithermal gold mineralization in the Cibaliung area is related to the volcanic activity that produced the Honje Formation, while the Cibaliung tuff played an important role in the preservation of the Cibaliung deposit. The Cibaliung deposit is the oldest epithermal gold deposit yet discovered in western Java.  相似文献   

11.
Abstract. Granitic rocks related to the formation of Haobugao Zn-Pb-Cu-Sn skarn deposit, Inner Mongolia, China, show unusual low whole-rock δ18O values down to -8.8 % (V-SMOW), whereas separated quartz crystals from those rocks give positive δ18O values of+4.1 to +9.9 %. Chemical analyses and microscopic observation of those granitic rocks confirm that they suffered hydrothermal alteration. Some skarn specimens and quartz from the Haobugao deposit also show negative δ18O values. The isotopic evidence indicates that intensive meteoric water circulation occurred at the time of granitic intrusion, and caused the pervasive hydrothermal alteration of granitic rocks and the precipitation of skarn deposit in this area.  相似文献   

12.
Nuclear waste that bore 90Sr2+ was accidentally leaked into the vadose zone at the Hanford site, and was immobilized at relatively shallow depths in sediments containing little apparent clay or silt-sized components. Sr2+, 90Sr2+, Mg2+, and Ca2+ was desorbed and total inorganic carbon concentration was monitored during the equilibration of this sediment with varying concentrations of Na+, Ca2+. A cation exchange model previously developed for similar sediments was applied to these results as a predictor of final solution compositions. The model included binary exchange reactions for the four operant cations and an equilibrium dissolution/precipitation reaction for calcite. The model successfully predicted the desorption data. The contaminated sediment was also examined using digital autoradiography, a sensitive tool for imaging the distribution of radioactivity. The exchanger phase containing 90Sr was found to consist of smectite formed from weathering of mesostasis glass in basaltic lithic fragments. These clasts are a significant component of Hanford formation sands. The relatively small but significant cation exchange capacity of these sediments was thus a consequence of reaction with physically sequestered clays in sediment that contained essentially no fine-grained material. The nature of this exchange component explained the relatively slow (scale of days) evolution of desorption solutions. The experimental and model results indicated that there is little risk of migration of 90Sr2+ to the water table.  相似文献   

13.
Calcium hydroxyapatite and calcite precipitates around bacteria were observed in 2-week-old alluvial topsoil (Roussillon area, SE France). This observation prompted a laboratory study of Ca2+ and PO43− incorporation into hydroxyapatite and Ca2+ into calcite mediated by bacteria using similar topsoil material, but free from apatite and calcite. Subsamples were prepared using three different grain sizes, and experiments were undertaken using sucrose and different contents of Ca2+ and PO43−. Mineralization experiments proceeded over 5 days. Calcium and PO43− sorption onto clay influenced the Ca/P ratio in the solutions. Hydroxyapatite and calcite precipitation only occurred in unsterilized samples. The presence of clay minerals promoted biomineralization.  相似文献   

14.
Abstract: A strange, unidentified, Cu-Fe bearing zinc sulfide occurs in the Laloki massive sulfide deposit, Papua New Guinea. The mineral is optically uniform in texture but is chemically variable and zoned even within a single grain. Copper contents vary from 0.1 up to 8.85 wt%. Iron reaches 18.31 wt% at maximum and decreases as Cu increases. It is remarkable, however, that the total Fe+Cu remains essentially unchanged between roughly 18 and 20 wt%. Zn and S are least variable, giving 45.85–47.84 wt% and 33.48–34.58 wt%, respectively. Other trace elements such as Cd and Mn are in general less than 0.2 wt%. It is strongly suggested that the mineral in question constitutes a unique Fe-Cu substitutional solid solution series belonging essentially to the Zn–Fe–Cu–S system.
The ideal chemical formula of the solid solution series can well be presented as Zn10(Fe, Cu)5S15 or Zn2(Fe, Cu)S3, where Fe is always greater than Cu. It is intriguing that chalcopyrite blebs are recognizable restrictively only in nearby portions of the Cu-rich end member with the ideal composition close to Zn10Fe3Cu2S15. It has been confirmed by vacuum-sealed heating experiments that this mineral is decomposed to produce chalcopyrite and Fe-bearing normal sphalerite at temperatures below 200C. This would provide another evidence for the existence of such distinct phase as suggested here.  相似文献   

15.
ABSTRACT
The mineralogy and isotope geochemistry of carbonate minerals in the Coorong area are determined by the water chemistry of different depositional environments ranging from seawater to evaporitically modified continental water. The different isotopic compositions of coexisting calcite and dolomite suggest that each of the above two minerals was formed from water of composition and origin unique to that specific mineral. In addition, the dolomite was not formed by simple solid state cation exchange.
The occurrence of two types of dolomite was shown by isotope analysis and SEM observations. The dolomite, which is isotopically light (δ13C = -1 to -2% 0 ; δ18O=+3 to +5%0) and of fine grain size (˜ 0·5 μm) probably precipitated under the influence of evaporitically modified continental water. Coarser grained dolomite (up to 4 μm) is isotopically heavier (δ13C=+3 to +4%0; δ18O=+5 to + 6%0) contains Mg in excess of Ca and was formed in or close to equilibrium with atmospheric CO2 probably by the dolomitization of aragonite.  相似文献   

16.
Abstract Two Archaean synvolcanic stocks with contact aureoles occur in the Wawa greenstone belt near Wawa, Ontario, Canada. The Gutcher Lake and Jubilee stocks consist mainly of granitoid trondhjemite with feldspar laths mottled by white mica + calcite + epidote and rimmed by clear albite. Biotite is partly or wholly pseudomorphosed by chlorite + sphene; some epidote is partly altered to calcite + chlorite. The granitoid phase grades into a foliated phase of quartz + albite + white mica + calcite + chlorite near fracture zones traversing the stocks.
The alteration of the Gutcher Lake stock along its foliated margin involved addition of K2O, H2O + CO2, MnO, plus Rb; loss of CaO plus Sr; and a shift in Fe+2/Fet from 0.66 to 0.81. The alteration of the Jubilee stock along the Darwin Shear involved addition of H2O + CO2; loss of Sr; and no significant shift in Fe+2/Fet. The greenschist alteration also modified the contact aureoles bordering both stocks.
One interpretation is that regional metamorphism in the Archaean overprinted a greenschist assemblage on both stocks. The alteration was intense near fracture zones and sporadic remote from fractures. Lower integrated water to rock ratios along the Darwin Shear compared to the margin of the Gutcher Lake stock may explain the comparatively lower perturbation of the element abundances and redox state of iron.  相似文献   

17.
Abstract. The Re-Os isotopic compositions of sulfide ores were analyzed for the Gacun, a volcanogenic massive sulfide deposit in southwestern China, to constrain the timing of mineralization. Sulfide ores from the deposit have a wide range of Re and Os concentrations, varying from 80.2 to 1543.2 ppb and from 0.307 to 8.83 ppb, respectively, and yielded a limited field of high 187Re/188Os and high 187Os/188Os ratios, ranging from 1452 to 3309 and from 5.77 to 13.24, respectively. All sulfide samples yielded an isochron with an age of 217±28 Ma and an initial 187Os/188Os ratio of around 0.52±0.73. The Re-Os isochron age agrees with ages previously constrained by the other isotopic dating of the host rocks and fossil strata for the deposit. The rhythmic variation in 187Os/188Os and 187Re/188Os ratios within massive sulfide zone records a complicated process for ore-forming fluids episodically vented into the brine pool on the Mesozoic seafloor.  相似文献   

18.
基于青藏高原昆仑山玉珠峰冰川Core 1冰芯钻取过程中所获得的相关资料,揭示出在该冰芯钻取点处的冰川内部34.34~34.64 m深度段存在一个富含水冰层,其未冻水(液态水)具有承压性质,水头高度至少可达到8.54 m. 该富含水冰层的存在不仅对冰川温度场带来了极大的影响,而且使该层中δ18O记录趋于均一化. 通过分析,揭示出该富含水冰层中可溶杂质离子浓度明显高于其上部冰层中的可溶杂质离子浓度,这是富含水冰层在形成初期其上部粒雪层融水下渗所引起的可溶杂质离子淋溶的结果. 同时,研究表明玉珠峰冰川粒雪中可溶杂质离子的优先淋溶顺序为NO3-> Mg2+> Na+> Cl-> K+> SO42-> Ca2+> NH4+. 提出可利用最易淋溶离子的浓度与最不易淋溶离子的浓度之比值,来判断冰雪层中可溶杂质离子浓度峰值是否与淋溶有关. 结合青藏高原其他地点冰芯钻取过程中发现的富含水冰层状况,认为青藏高原冰川内部富含水冰层不是在整个冰川区域内呈层状分布,而是在冰川内部呈透镜状分布. 冰川内部富含水冰层的存在,表明其形成初期气候相对较暖. 最后,阐明了青藏高原冰川中富含水冰层的形成机理与演化过程,并预测了其潜在的灾害效应.  相似文献   

19.
Abstract. Laser Raman microprobe analysis was performed on the fluid inclusions from the Honko-Sanjin zone in the Hishikari epithermal gold deposit, southern Kyushu, Japan. Gas concentrations of fluid inclusions through the zone were below detection limits (e.g., 5 mmole/kg H2O for CO2), with an exception at shallow portion in which the CO2/N2 mole ratio was determined to be 5.3. Boiling of hydrothermal solutions probably separated gases from ore fluids at the deep portion of the deposit, and migration of gases to shallow portion resulted in CO2-rich steam-heated water and related acid alteration.  相似文献   

20.
Abstract. Vein type tungsten mineralization at Degana is genetically and spatially associated with the Degana Granite. The deposit is characterized by pervasive wall rock alteration around the mineralized quartz veins. Laterally three different alteration zones, greisen, silicification and potassic zones, are marked based on the field features, mineral assemblages and geo-chemical characteristics. In the present paper, systematic mineralogical and chemical variation in these alteration zones is reported. Thick mono-mineralic (zinnwaldite) selvages around the veins characterize the deposit. Plagioclase and alkali feldspar are low in the greisen zones while K-feldspar shows more increase than plagioclase in the potassic zone. Quartz is uniformly high in all the alteration zones, but it shows an anomalous value in the silicification zone. Al2O3 concentration shows initial depletion in greisen zone with gradual increase away from the contact. MgO and FeO are higher in greisen zone than silicification and potassic zones. The potassic zone is characterized by the depletion of Na2O and higher value of K2O.
The common presence of topaz and fluorite as both primary and secondary minerals and fluorine-bearing micas suggest fluorine partitioning in substantial amount between granitic melt and coexisting aqueous fluid phase and higher HF activity during the evolution of hydrothermal fluid. The mutual relationship of the fluorine minerals (topaz and fluorite) in the different alteration zones suggests an increase in the Ca2+ activity and decrease of H+ activity during the fluid evolution from greisenization towards alkali-metasomatised granite and the fluid is assumed to change from low to high activity ratio of Ca2+/H+.  相似文献   

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