Fluid and melt inclusion evidence for the origin of idiomorphic quartz crystals in topaz-bearing granite from the Salmi batholith, Karelia, Russia   总被引：1，自引：0，他引：1  

M. Poutiainen  T. F. Scherbakova 《Lithos》1998,44(3-4):141-151

Idiomorphic quartz crystals in topaz-bearing granite from the Salmi batholith contain primary inclusions of silicate melt and abundant mostly secondary aqueous fluid inclusions. Microthermometric measurements on melt inclusions give estimates for the granite solidus and liquidus of 640–680°C and 770–830°C, respectively. Using published solubility models for H₂O in granitic melts and the obtained solidus/liquidus temperatures from melt inclusions, the initial water concentration of the magma is deduced to have been approximately 3 wt.% and the minimum pressure about 2 kbar. At this initial stage, volatile-undersaturation conditions of magma were assumed. These results indicate that the idiomorphic quartz crystals are magmatic in origin and thus real phenocrysts. During subsolidus cooling and fracturing of the granite, several generations of aqueous fluid inclusions were trapped into the quartz phenocrysts. The H₂O inclusions have salinities and densities of 1–41 wt.% NaCl eq. and 0.53–1.18 g/cm³, respectively.  相似文献   

Determination of characteristics of steam reservoirs by Radon-222 measurements in geothermal fluids     

F. D'Amore  J. C. Sabroux  P. Zettwoog 《Pure and Applied Geophysics》1978,117(1-2):253-261

The authors conducted a Rn²²² survey in wells of the Larderello geothermal field (Italy) and observed considerable variations in concentrations. Simple models show that flow-rate plays an important part in the Rn²²² content of each well, as it directly affects the fluid transit time in the reservoirs. Rn²²² has been sampled from two wells of the Serrazzano area during flow-rate drawdown tests. The apparent volume of the steam reservoir of each of these two wells has been estimated from the Rn²²² concentration versus flow-rate curves.List of symbols Q Flow-rate (kg h^–1) - Decay constant of Rn²²² (=7.553×10^–3 h^–1) - Porosity of the reservoir (volume of fluid/volume of rock) - ₁ Density of the fluid in the reservoir (kg m^–3) - ₂ Density of the rock in the reservoir (kg m^–3) - M Stationary mass of fluid filling the reservoir (kg). - E Emanating power of the rock in the reservoir (nCi kg _rock ^–1 h^–1). - P Production rate of Rn²²² in the reservoir: number of atoms of Rn²²² (divided by 1.764×10⁷) transferred by the rock to the mass unit of fluid per unit time (nCi kg _fluid ^–1 h^–1). - N Specific concentration of Rn²²² in the fluid (nCi kg^–1) - Characteristic time of the steam reservoir at maximum flow-rate (=M/Q)  相似文献   

普朗斑岩铜矿包裹体、同位素研究及成矿时代     

胡清华  黄定柱  李冰  杨丽梅  尹光候 《云南地质》2010,29(3):351-357

普朗斑岩铜矿产于印支-燕山早期普朗复式斑岩体中。成矿流体来源广、盐度高,成矿温度从高温440℃到低温120℃,集中在160℃-240℃、280℃-320℃、340℃-380℃三阶段,多期次、多阶段性,与斑岩成矿作用特征一致。硫同位素3δ4SCDT‰T为（-2.23-3.75）‰,显示单一深源岩浆硫。岩体黑云母等40Ar-39Ar和矿石石英-辉钼矿Re-Os同位素年龄为206.4M a-213±3.8M a,属岛孤斑岩型铜矿床。  相似文献   

新疆阿尔泰克因布拉克铜锌矿床地质特征及成矿作用   总被引：4，自引：1，他引：3  

杨富全  毛景文  刘锋  董永观  柴凤梅  耿新霞 《岩石学报》2010,26(2):361-376

克因布拉克中型铜锌矿床赋存于早二叠世花岗岩外接触带的上志留统-下泥盆统康布铁堡组黑云石英片岩、变质石英砂岩中。矿床的形成经历了夕卡岩期、热液期和表生期,铜锌矿主要形成于热液期。矿石中石英和方解石流体包裹体划分为H_2O-NaCl型和H_2O-CO_2(±CH_4/N_2)-NaCl型。成矿温度变化于146～448℃,在170℃、270℃和350℃出现峰值;流体盐度变化于0.2%～46.9%NaCl_(eq),峰值为1.5%NaCl_(eq)和5.5%NaCl_(eq);流体的密度0.55～1.19g/cm~3。硫化物的δ~(34)S集中变化于-8.4‰～1.9‰,峰值为0‰,表明硫来自岩浆。石英和方解石δD_(SMOW)介于-130‰～-79‰,δ~(18)O_(SMOW)值介于8.0‰～11.6‰,δ~(18)O_(H2O)值为-1.7‰～4.43‰,表明成矿流体主要是岩浆水,混合大气降水。方解石中δ~(13)C_(PDB)变化于-5.3‰～-1.1‰,暗示碳来自花岗质岩浆。成矿时代为早中二叠世,成矿作用与花岗质岩浆期后的热液活动有关。  相似文献   

西拉沐伦钼矿带车户沟斑岩型钼-铜矿床成矿流体特征及其地质意义   总被引：9，自引：4，他引：5  

褚少雄  曾庆栋  刘建明  张伟庆  张作伦  张松  汪在聪 《岩石学报》2010,26(8):2465-2481

车户沟钼-铜矿床是华北克拉通北缘西拉沐伦钼矿带上典型的斑岩型Mo-Cu矿床,位于华北克拉通北缘断裂南侧。矿床赋存于成矿母岩花岗斑岩及其围岩中,矿化类型以细脉浸染状矿化为主,还存在隐爆角砾岩型矿化和石英脉型矿化。根据脉体类型和矿物组合将车户沟钼-铜矿床划分为四个成矿阶段,分别为(1)辉钼矿-黄铁矿-石英阶段、(2)黄铜矿+黄铁矿±辉钼矿+石英阶段、(3)黄铁矿+石英阶段、(4)石英+碳酸盐±萤石阶段。成矿流体寄主矿物石英中发育Ⅰ型含CO2三相包裹体(LCO2+VCO2+LH2O)、Ⅱ型含子晶三相(V-L+S)包裹体、Ⅲ型富气相(V-L)包裹体、Ⅳ型富液相(L-V)包裹体、Ⅴ型纯气相(V)包裹体和Ⅵ型纯液相(L)六种类型。流体包裹体类型从早到晚具有规律性演化特征,表现为阶段(1)、(2)以发育Ⅰ型含CO2三相包裹体(LCO2+VCO2+LH2O)和Ⅱ型含子晶三相(V-L+S)包裹体为特征,成矿晚期阶段(3)、(4)以发育Ⅲ型富气相(V-L)包裹体、Ⅳ型富液相(L-V)水溶液包裹体为特征。从早阶段到晚阶段成矿流体温度及盐度具有规律性演化特征。均一温度峰值分别为270～400℃、230～370℃、160～290℃、120～230℃,成矿温度逐渐降低;流体盐度,阶段(1)流体盐度分两组:3.39%～14.25%NaCleqv和31.01%～66.75%NaCleqv、阶段(2)流体盐度分两组:1.23%～12.85%NaCleqv和31.14%～64.33%NaCleqv、阶段(3)、(4)盐度分别介于1.05%～21.47%NaCleqv和2.07%～10.73%NaCleqv,盐度逐渐降低。激光拉曼显微探针(LRM)及群体包裹体成分分析结果表明,流体体系成分以H2O、CO2、Cl-、SO42-、Na+为主,贫F-、Ca2+、Mg2+为特征,特征离子比值暗示流体来源于岩浆流体。包裹体岩相学及包裹体测温表明,流体由早期的高温、高盐度、含二氧化碳NaCl-H2O-CO2体系岩浆流体在主成矿阶段(1)、(2)发生流体包裹体的沸腾作用和相分离,伴随流体沸腾、CO2逸失、温度降低等过程导致大量金属硫化物沉淀。成矿晚期阶段(3)、(4),成矿体系趋于开放,流体存在大气降水混入演化为晚期中-低温、中-低盐度贫CO2的NaCl-H2O流体体系。成矿作用机制上沸腾作用是导致主成矿期辉钼矿、黄铜矿沉淀成矿的重要机制。成矿作用晚期阶段(3)、(4)流体混合作用成为成矿作用的主导机制。  相似文献   

长江中下游池州地区矽卡岩-斑岩型W-Mo矿床流体包裹体与H、O、S同位素研究   总被引：7，自引：5，他引：2  

宋国学  秦克章  李光明 《岩石学报》2010,26(9):2768-2782

长江中下游池州地区区域构造上处于下扬子坳陷与江南古陆之间的过渡带上,近年来该区域内以钨钼为主的多金属矿床勘探方面取得了很大突破,鸡头山矽卡岩-斑岩型W-Mo矿、马头斑岩型Mo矿和百丈岩矽卡岩-斑岩型W-Mo矿是其中的三个代表性矿床。在鸡头山矿区和百丈岩矿区钨钼主要赋存于矽卡岩体中,已有工程探明二者的深部都有斑岩型矿体存在;在马头矿区钼主要以含钼石英脉和辉钼矿细脉的形式赋存于近接触带岩体与围岩中。流体包裹体研究表明,池州地区与钨钼矿有关的流体包裹体以水溶液包裹体(L+V)为主,同时发育含子矿物包裹体(L+V+S)和CO2包裹体(L+LCO2+VCO2)。成矿流体演化分为三个阶段:早阶段温度在350～500℃之间,深度约为1.5～2.5km,初始流体盐度为17%～25%NaCleqv,流体富H2O-CO2-CH4等气体,流体发生沸腾作用分离出高盐度流体和富气相低盐度流体;中阶段温度在170～360℃之间,深度约为0.5～1.7km,盐度为2%～24%NaCleqv,富H2O-CO2-CH4-H2S等气体,流体混合作用使得大量钨、钼、铅、锌等金属沉淀成矿;晚阶段温度在100～160℃之间,深度在约0.6km以下,盐度范围为1%～10%NaCleqv,与成矿作用无关。含矿石英脉H-O同位素和硫化物S同位素共同指示,池州地区与钨钼矿有关的成矿流体来自岩浆水、大气水和建造水的混合,流体混合是区域钨-钼-铅-锌成矿的主要机制。  相似文献   

构造应力环境对浅成岩体成矿系统的制约:从安庆月山岩体冷却过程动力学计算模拟结果分析   总被引：2，自引：0，他引：2  

刘亮明  周瑞超  赵崇斌 《岩石学报》2010,26(9):2869-2878

为探讨构造应力环境对浅成岩体成矿系统的制约,以安庆地区的月山岩体及其所形成的安庆铜矿床为例,在传统地质调查研究的基础上,通过假设不同的力学边界条件进行岩体冷却过程动力学的计算模拟实验研究。计算结果显示,在没有构造应力作用时,在岩体的接触带上不可能形成有利成矿定位的局部汇流扩容空间,挤压和拉伸作用都能够在岩体接触带形成局部汇流扩容空间,但二者的空间分布规律有着极大的差别,只有拉伸构造应力作用下的动力学计算模拟实验能在已发现矿体部位形成汇流扩容空间,表明构造应力环境对成矿定位的汇流空间的制约以及拉伸构造应力作用对月山岩体成矿的重要贡献。在拉伸构造应力和无构造应力作用时,接触带上的流体压力都是随着变形的进程而趋降低的,只有在挤压构造应力作用下,流体压力才会有一个超压的过程,流体超压是形成斑岩型矿床的重要机制。可见挤压环境才是一种有利于斑岩型矿床成矿的构造环境,铜陵-安庆地区缺乏与矽卡岩矿床相对应的斑岩型矿床主要原因之一是成矿时处于一种拉伸的构造应力作用环境。  相似文献   

山东金岭金矿床成矿流体地球化学特征   总被引：4，自引：0，他引：4  

王力  孙丰月  王佳良 《岩石学报》2010,26(12):3735-3744

对山东金岭金矿矿石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研究。结果表明:金矿石中发育含CO2相、气液两相和CO2相等三类包裹体,成矿过程中,流体经历了NaCl-H2O-CO2体系的不混溶作用;成矿流体具有低盐度(6.6%~10.8%NaCleqv)、低密度(0.54~0.93g.cm-3)的特点;成矿温度集中于280~300℃之间,成矿压力为70~119MPa,成矿深度为6.78~9.07km;矿石石英中流体包裹体成分普遍含CO2。结合新近的流体包裹体同位素分析结果和测年数据,认为成矿流体为地幔流体、岩浆流体和大气降水的混合产物,矿床成因类型为幔源流体参与成矿的造山型金矿床中成亚类。  相似文献   

Mud volcanism and fluid geochemistry in the Cheleken peninsula,western Turkmenistan     

《Marine and Petroleum Geology》2014

A geological and geochemical study has been carried out to investigate the relationships between major mud volcano structures and deep fluid migration in the Cheleken peninsula, in the South Caspian Basin. The fluid geochemistry allowed the origin and migration of the saline waters and the hydrocarbons to be deduced along with the regional source and reservoir rocks. The emitted waters formed by the mixing of deep highly saline water from the main source rocks of the Maykop Fm with the Caspian-like pore water contained in the Pliocene reservoirs. The water composition is very similar to that emitted by the mud volcanoes in Azerbaijan, allowing comparisons to be done between the reservoirs in the western and eastern sides of the South Caspian Basin. The associated oil is derived from a mixed type II/III kerogen deposited in a sub-oxic marine environment and generated during the early oil window. The oil biomarkers indicate that the source rock is the Maykop Fm., as previously determined for the other areas of the South Caspian Basin.The spontaneous emissions, showing different morphologies, are mainly aligned along normal and transtensive fault systems, which provide effective pathways for rapid fluid ascent from deep reservoirs to the surface.  相似文献   

Geochronology and fluid inclusion study of the Yinjiagou porphyry–skarn Mo–Cu–pyrite deposit in the East Qinling orogenic belt,China     

《Journal of Asian Earth Sciences》2014

The Yinjiagou Mo–Cu–pyrite deposit of Henan Province is located in the Huaxiong block on the southern margin of the North China craton. It differs from other Mo deposits in the East Qingling area because of its large pyrite resource and complex associated elements. The deposit’s mineralization process can be divided into skarn, sulfide, and supergene episodes with five stages, marking formation of magnetite in the skarn episode, quartz–molybdenite, quartz–calcite–pyrite–chalcopyrite–bornite–sphalerite, and calcite–galena–sphalerite in the sulfide episode, and chalcedony–limonite in the supergene episode. Re–Os and ⁴⁰Ar–³⁹Ar dating indicates that both the skarn-type and porphyry-type orebodies of the Yinjiagou deposit formed approximately 143 Ma ago during the Early Cretaceous. Four types of fluid inclusions (FIs) have been distinguished in quartz phenocryst, various quartz veins, and calcite vein. Based on petrographic observations and microthermometric criteria the FIs include liquid-rich, gas-rich, H₂O–CO₂, and daughter mineral-bearing inclusions. The homogenization temperature of FIs in quartz phenocrysts of K-feldspar granite porphyry ranges from 341 °C to >550 °C, and the salinity is 0.4–44.0 wt% NaCl eqv. The homogenization temperature of FIs in quartz–molybdenite veins is 382–416 °C, and the salinity is 3.6–40.8 wt% NaCl eqv. The homogenization temperature of FIs in quartz–calcite–pyrite–chalcopyrite–bornite–sphalerite ranges from 318 °C to 436 °C, and the salinity is 5.6–42.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz–molybdenite stockworks is in a range of 321–411 °C, and the salinity is 6.3–16.4 wt% NaCl eqv. The homogenization temperature of FIs in quartz–sericite–pyrite is in a range of 326–419 °C, and the salinity is 4.7–49.4 wt% NaCl eqv. The ore-forming fluids of the Yinjiagou deposit are mainly high-temperature, high-salinity fluids, generally with affinities to an H₂O–NaCl–KCl ± CO₂ system. The δ¹⁸O_H2O values of ore-forming hydrothermal fluids are 4.0–8.6‰, and the δD_V-SMOW values are between −64‰ and −52‰, indicating that the ore-forming fluids were primarily magmatic. The δ³⁴S_V-CDT values of sulfides range between −0.2‰ and 6.3‰ with a mean of 1.6‰, sharing similar features with deeply sourced sulfur, implying that the sulfur mainly came from the lower crust composed of poorly differentiated igneous materials, but part of the heavy sulfur came from the Guandaokou Group dolostone. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb values of sulfides are in the range of 17.331–18.043, 15.444–15.575, and 37.783–38.236, respectively, which is generally consistent with the Pb isotopic signature of the Yinjiagou intrusion, suggesting that the Pb chiefly originated from the felsic–intermediate intrusive rocks in the mine area, with a small amount of lead from strata. The Yinjiagou deposit is a porphyry–skarn deposit formed during the Mesozoic transition of a tectonic regime that is EW-trending to NNE-trending, and the multiepisode boiling of ore-forming fluids was the primary mechanism for mineral deposition.  相似文献