内蒙古虎拉林金矿地质特征及成因分析

虎拉林金矿床位于漠河盆地西部边缘,地质、地球化学特征与盆地其他金矿床具有明显的区别,金矿(化)体赋存于近南北向角砾岩带及张性断裂中。虎拉林金矿成矿作用可以划分为5个阶段,分别为星点状黄铁矿-石英阶段(Ⅰ)、黄铁矿±闪锌矿-石英阶段(Ⅱ)、黄铁矿+闪锌矿±黄铜矿-石英阶段(Ⅲ)、多金属硫化物-石英阶段(Ⅳ)和碳酸盐-石英阶段(Ⅴ),主要成矿阶段为Ⅱ、Ⅲ和Ⅳ。含金石英脉中流体包裹体发育有气液两相、CO_2三相、含子矿物三相和少量纯气相包裹体等。均一温度依次出现了401℃～590℃、313℃～388℃和228℃～246℃三个区段,含子矿物包裹体盐度总体介于48.4%～64.52%(NaCleqv),其他介于5.7%～21.80%(NaCleqv),属中高温、中高盐度H_2O-CO_2-NaCl流体。初步认为虎拉林金矿床成矿物质来源于深部岩浆,成矿时代为早白垩世早期,属中高温热液隐爆角砾岩型金矿床。     

青海省四角羊沟铅锌多金属矿床流体包裹体特征及成因探讨

四角羊沟矿区位于我国著名成矿带之一的东昆仑造山带西段,矿体位于矽卡岩带内,矿床类型为矽卡岩型铅锌矿。流体包裹体研究表明,矿区内的包裹体为水溶液两相包裹体。根据显微测温结果,早期硫化物阶段的流体包裹体均一温度在209~411℃,盐度介于3.06~11.46%（质量分数,NaCl equiv,下同）之间;晚期硫化物阶段样品的均一温度在151~396℃,盐度介于0.18~6.3%。晚期流体中的Ca＋含量的增高,显示出围岩中低温高Ca2＋流体的混入,致使流体温度和盐度的下降,导致金属矿物的沉淀富集。     

浅成低温热液型金矿成矿流体特征

本文总结了浅成低温热液金矿床的成矿流体特征,其流体的均一温度低于300℃,属于低温低盐度体系。流体中含有大量的CO2组分以及Na+、K+、Ca2+、Mg2+等离子。重点讨论了浅成低温热液金矿床与斑岩型矿床的关系,认为浅成低温热液金矿床与斑岩型矿床是一套完整的斑岩-浅成低温热液成矿流体体系。     

内蒙古库伦旗卧力吐铅锌矿床地质特征及成因研究

卧力吐铅锌矿床是大兴安岭南段地区近年来发现的一处小型铅锌矿床,本文通过系统的矿床地质特征、矿相学及成矿机制的研究,表明卧力吐铅锌矿床属岩浆期后热液填充—交代矿床,可划分为毒砂-石英阶段—铅、锌、银硫化物-石英阶段—碳酸盐-石英3个成矿阶段,矿床成因与燕山期黑云母花岗岩密切相关。     

东天山地区晚古生代成矿规律总结

晚古生代是新疆东天山地区最重要的成矿时代,在晚古生代东天山地区经历了绝罗榙格地区裂陷槽形成和康古尔塔格韧性剪切带形成。其构造演化伴随了大量矿产的形成,时间和空间上具有明显的分布规律,早石炭世以Cu-Pb-Zn矿化为特色,主要形成了火山一次火山作用有关的热液型铜、铅、锌矿床;晚石炭世以火山一次火山热液型和岩浆熔离型成矿最为发育,其中火山—次火山热液型矿床以铜、金矿化为主,岩浆熔离型矿床以铜镍硫化物矿床为主,早二叠世是东天山的成矿高峰期,成矿作用主要与中酸性岩浆活动和动力变质热液活动有关,其中岩浆热液型以金铜矿床为主;晚二叠世仅见有动力变质热液型叠加金矿化。空间上吐哈盆地南缘(北带)铜矿带,康古尔(中带)金矿带,阿齐山—雅满苏(南带)铁、铜、银多金属成矿带以及中天山地块铁、铅锌、银成矿带。     

内蒙古西乌珠穆沁旗哈日根台矿区银锌多金属矿矿床地质特征及成因初探

哈日根台矿区位于大兴安岭中南段西坡银多金属成矿带,矿体产于林西组(P2l)变质(泥质)粉砂岩中,受近南北向张性断裂构造控制。根据野外脉体穿插关系和矿石结构构造特征可以将成矿分为4个阶段,即毒砂-黄铁矿-石英阶段、黄铁矿-黄铜矿-闪锌矿阶段、银多金属硫化物阶段及锡石-石英阶段。结合区域成矿地质背景和矿床地质特征,认为该矿床是一受构造控制的、与燕山早期酸性岩浆活动有关的中高温热液矿床。     

论钾盐矿床的物质来源和找矿指示

讨论了钾及其有关物质的理化性质和行为规律,钾盐的物质来源,盐卤的变质,结晶分异,成矿条件和机制,认为富钾热液是形成钾盐矿床的重要的物质来源之一。矿物岩石流体包裹体的富钾成分、富钾热泉、富钾盐湖均是找寻钾盐矿床的重要指示。     

新疆查岗诺尔铁矿地质特征及成矿期次划分

新疆和静县查岗诺尔铁矿床位于伊犁微板块北缘博罗科努岛弧带.矿区广泛出露石炭纪火山岩.该矿床由6个矿体组成,其中FeⅠ矿体为该铁矿床的主要矿体.主要矿石矿物磁铁矿的化学成分组成中,Fe2O3含量与SiO2含量大致呈此消彼长关系.矿区的主要矿物共生组合为磁铁矿+石榴石+阳起石(绿帘石)组合.矿床大致可以分为2个成矿时期和5个成矿阶段,即隐爆-矿浆成矿时期的矿浆成矿阶段和热液成矿阶段;隐爆-热液成矿期的磁铁矿-石榴石阶段、阳起石-绿帘石阶段和石英-碳酸盐阶段.矿床成因属于受到热液作用叠加改造的火山岩型铁矿床.     

内蒙古三河铅锌矿床同位素特征与矿床成因探讨

三河铅锌矿床主要产于北西西向的构造裂隙中,矿体多呈脉状、透镜状,严格受构造的控制,矿床成因类型为中低温岩浆热液型铅锌矿床。该矿床处于得尔布干成矿带的北段,构造发育,岩浆活动频繁。铅同位素数据指示成矿金属来自地幔和地壳,硫同位素δ34SCDT在+1.6‰~+6.2‰之间,具有幔源岩浆热液来源的特征。成矿热液的主体是以岩浆水和大气降水的混合水为主。     

湖北夷陵花岩钼矿床地质特征及开采条件分析

花岩钼矿床位于鄂西黄陵背斜,属斑岩型钼矿。钼矿主要产出在第一岩浆旋回晚期过渡相的含钼的石英脉及其蚀变带中与成矿有关的围岩蚀变以中低温热液蚀变为主。区内水文地质、工程地质为简单类型,环境地质条件中采空区引发地面变形和矿山排泄物污染水、土的问题,需要采取相应措施处理和预防,环境地质类型为第二类,该矿床开采技术条件勘查类型为Ⅱ-3,即环境地质问题为主的矿床。     

The role of fluid inclusions in mineral exploration—An attempt on the Bihar Mica Belt of India

Fluid inclusions and melt inclusions have been considered as possible guides for mineral exploration by many researchers. However, the minuteness of the fluid inclusions and the multiplicity of generations within the same deposit have always posed serious problems in the proper utilization of fluid-inclusion data in prospecting.Fluid inclusions preserve a valid and comprehensive record of the fluids coexisting with host minerals at the time of crystallization. A careful comparison of fluid-inclusion parameters and deposit characteristics enables one to distinguish between economically significant and insignificant zones of pegmatites.A systematic study of different pegmatites in an area of about 100 km² in the central part of the Bihar Mica Belt, India, was made. Mineralogical, fluid-inclusion, and melt-inclusion data of the principal mineral constituents like quartz, beryl, and apatite were collected. Thirty-three occurrences were chosen for the study. Pegmatites were grouped into economically significant (commercial) and barren (noncommercial) types. The fluid-inclusion parameters used in this study are size, population, presence of liquid carbon dioxide, salinity, and temperature of homogenization.Economically significant pegmatites and barren pegmatites have distinctly different populations of fluid inclusions. Economic pegmatites show a preponderance of highly saline, polyphase fluid inclusions, commonly with liquid carbon dioxide; these fluid inclusions homogenize over a wide range of temperature. Their size ranges from 50 m to 10 m. On the other hand, quartz of barren pegmatites is characterized by the preponderance of vapor-rich biphase inclusions, which homogenize at a relatively narrower but higher range of temperature. Fluid inclusions that contain halite daughter crystals are rare. The average size of the fluid inclusions in barren pegmatites is smaller (5 m to 20 m). Melt inclusions are more abundant in the barren pegmatites.     

南极乔治王岛长城站地区火山岩中矿物包裹体的研究

本文主要讨论了长城站地区第三纪火山岩系的透辉石和斜长石中熔融包裹体的特征、均一温度、挥发组分、玻璃和子矿物的化学成分。透辉石中熔融包裹体均一温度为1070～1170℃,斜长石中熔融包裹体均一温度m≥1100℃。透辉石和斜长石熔融包裹体气泡中组分CO_2为45～93％,H_2S为微量～35％,CH_4为2～20％和CO为2～14％,少量为N_2,O_2,H_2O和H_2。这些组分从火山喷发早期至晚期呈规律性变化。对熔融包裹体的玻璃和子矿物进行成分测定,其子矿物为钙铁橄榄石。     

Fluid inclusions as constraints in a three‐dimensional hydro‐thermo‐mechanical model of the Paris basin,France

Fluid inclusion homogenization temperatures and three‐dimensional hydro‐thermo‐mechanical modelling were combined to constrain fluid flow, solute and heat transport in the Paris basin, France, focusing on the two main petroleum reservoirs i.e. the Dogger and the Triassic (Keuper) formations. The average homogenization temperatures of two‐phase aqueous inclusions in different samples range from 66 °C to 88 °C in the Dogger calcite cement, from 106 °C to 118 °C in the Keuper dolomite cement and from 89 °C to 126 °C in the Keuper quartz and K‐feldspar cements. The maximum homogenization temperatures for inclusions in the Keuper quartz and K‐feldspar cements were 17–47 °C higher than present‐day temperatures in the boreholes at similar depths. Processes that might explain higher temperatures in the past were examined through numerical simulations and sensitivity tests. A warmer climate in the Late Cretaceous–Early Tertiary resulted in a temperature rise of only 8 °C. Late Cretaceous chalk had a thermal blanketing effect that resulted in simulated temperatures as high as 15–20 °C above the present day ones. An additional 300 m deposition and subsequent erosion of chalk, not taken into account so far, has to be considered to simulate the high palaeo‐temperatures recorded by fluid inclusions in both reservoirs. In view of the simulated thermal history of the basin, in the Keuper, an age of about 85 Ma is consistent with quartz/K‐feldspar temperatures and an age of about 65 Ma is in agreement with the precipitation temperature of the dolomite cement. Our models suggest an age of about 50 Ma for the Dogger calcite cementation.     

Basin evolution,diagenesis and uranium mineralization in the Paleoproterozic Thelon Basin,Nunavut, Canada

The Paleoproterozoic (Statherian) Thelon Basin is located in the Churchill Province of the Canadian Shield, formed following the Trans‐Hudson Orogeny. Basin formation followed an interval of felsic volcanism and weathering of underlying bedrock. The diagenetic evolution of the Thelon lasted about one billion years and was punctuated by fluid movement influenced by tectonic events. Early quartz cements formed in well‐sorted, quartz‐rich facies during diagenetic stage 1; fluids in which these overgrowths formed had δ¹⁸O values near 0‰ (Vienna Standard Mean Ocean Water). Uranium‐rich apatite cement (P1) also formed during diagenetic stage 1 indicating that oxygenated, uranium‐bearing pore water was present in the basin early in its diagenetic history. Syntaxial quartz cement (Q1) formed in water with δ¹⁸O from ?4 to ?0.8‰ in diagenetic stage 2. Diagenetic stage 3 occurred when the Thelon Formation was at ca. 5 km depth, and was marked by extensive illitization, alteration of detrital grains, and uranium mineralization. Basin‐wide, illite crystallized at ～200 °C by fluids with δ¹⁸O values of 5–9‰ and δD values of ?60 to ?31‰, consistent with evolved basinal brines. Tectonism caused by the accretion of Nena at ca. 1600 Ma may have provided the mechanism for brine movement during deep burial. Diagenetic stage 4 is associated with fracturing and emplacement of mafic dikes at ca. 1300 Ma, quartz cement (Q3) in fractures and vugs, further illitization, and recrystallization of uraninite (U2). Q3 cements have fluid inclusions that suggest variable salinities, δ¹⁸O values of 1.5–9‰, and δD values of ?97 to ?83‰ for stage 4 brines. K‐feldspar and Mg‐chlorite formed during diagenetic stage 5 at ca. 1000 Ma in upper stratigraphic sequences, and in the west. These phases precipitated from low‐temperature, isotopically distinct fluids. Their distribution indicates that the basin hydrostratigraphy remained partitioned for >600 Ma.     

Deciphering some unique paleotemperature indicators in halite-bearing saline lake deposits from Death Valley, California, USA

Saline lake deposits are arguably the best source of mid- to low-latitude terrestrial paleoclimate data. Alternating clastic sediments and evaporites of different chemical composition have long been recognized as sensitive records of changes in inflow and aridity related to a variety of climate parameters. Several sources of paleotemperature information from a halite-bearing saline lake deposit are described here – pseudomorphs of a cold-temperature evaporite mineral, homogenization temperatures of fluid inclusions in halite, and stable-isotope compositions of fluid inclusions in halite. Examples of these paleoclimate data come from analysis of the lower half of a 185-m core drilled in Pleistocene saline lake deposits at Death Valley, California. Daily and seasonal temperature variations in saline lake waters create conditions for the appearance and disappearance of temperature-dependent mineral phases. In the Death Valley core, hexagonal-shaped halite crystals, probable pseudomorphs of the cold-temperature hydrous mineral, hydrohalite (NaCl2H₂O), provide evidence of brine temperatures below about 0 °C. Homogenization temperatures of fluid inclusions in primary halite offer an actual (not proxy) record of surface-brine temperatures. Samples with primary fluid-inclusion textures are carefully selected and handled, and data are collected from single-phase aqueous-brine inclusions chilled to nucleate vapor bubbles. Temperature variations are observable at scales of individual halite crystals (hours to days), single halite beds (weeks to months or years), and multiples of beds to entire facies (hundreds to tens of thousands of years). A ¹⁸O/D stable isotope record from the minute quantities of brines in fluid inclusions in halite is accessible using a method recently developed at the University of Calgary. The stable isotope record from the Death Valley core, a complex response to climate variables including temperature, humidity, storm patterns or seasons, and inflow sources, compliments and expands the interpretation emerging from the stratigraphy and homogenization temperatures.     

察尔汗盐湖钾盐矿床与晶间卤水分异的关系

通过钾盐矿床与晶间卤水分异特征及成因的分析对比，认为晶间卤水分异的过程也就是钾盐矿床形成的过程。胶结浸染状固体矿形成于晶间卤水分异初期的浓缩阶段，改造于分异后期的淡化阶段；晶间卤水矿和层状固体矿形成于淡化阶段。     

Three-dimensional geological environment simulation of submarine exhalative sediments

On the basis of the major metal grades from the super-large Bainiuchang Ag-rich polymetallic ore deposit, enrichment evolution processes were divided into three populations by using a new multiple time-series model. Population 1 shows the highest temporal/spatial autocorrelation with the ore-forming processes. Population 3 is considered to be a white noise process. The lithologies of populations 1 and 2 are closely related to submarine exhalative hydrothermal sedimentation. By using a semi-Markov process and a dynamic lithologic ratio parameter model, the paleogeographic environment of the bathyal basin in which the Bainiuchang Agrich polymetallic ore deposit formed was simulated. The result of the simulation suggests that four major submarine exhalation cycles occurred during basin evolution. Hydrothermal sedimentary metallization took place in the middle stage of each cycle. Hydrothermal sedimentation in each of the four cycles suggests an evolution from weak to strong to stronger to weak. Debris and turbidity currents related to syndepositional faulting along the northwestern margin of the basin and submarine hydrothermal exhalation originated from vents and flowed from northwest to southeast. A three-dimensional, finite-element method was used to simulate quantitatively the dynamic evolution of the temperature field of heat fluid circulation. A model is proposed that allows for the submarine heat fluid circulation from seawater that percolates downward, the upflow along a syndepositional falut to exhalation on the seafloor, and the formation of lenticular ore bodies in a single tectonic pulse. Comparison of the simulated temperature field and the mixing population of thermometric data of fluid inclusions suggests that the major submarine exhalation took about 35,000 years and that after 15,000 years from the initial establishment of the temperature field, the temperature of heat fluid circulation at the vents reached a maximum of 280°C.     

乔治王岛东北海域大磷虾虾群构成分析

1985年1月在乔治王岛东北约25海里(水深460米)海域,曾观测到范围较大的大磷虾群.在约4海里范围内用垂直探鱼仪记录了虾群的映象,进行了水平拖网.对6网样品的分析结果表明,虾群组成相当均一.体长频数分布样品间的百分比相似性指数平均为84.3%,性成熟度组成频数分布的相似性指数平均为75.6%,说明这些样品属同一虾群.磷虾平均体长为46.8毫米,成体虾占群体的96.5%,表明它们为一生殖群体.群体分布水层在20—50米深,厚度一般为20米,平均密度为1400尾/千立方米.     

河南省罗山县陡坡花岗斑岩型钼矿床地质特征及成因探讨

陡坡钼矿床是一新发现的中型钼矿床,该矿床赋存于早白垩世灵山超单元岩体与围岩的接触带内侧,矿化类型主要为细脉浸染状。矿床中金属矿物主要为黄铜矿、辉钼矿、方铅矿、闪锌矿、黄铁矿、磁铁矿、赤铁矿,次为磁黄铁矿、斑铜矿等。灵山超单元花岗岩岩石类型属高硅富碱钙碱性(偏碱性)系列,SiO2含量72～77%,K2O+Na2O总量大于7.9%,K2O/Na2O大于1。矿床的围岩蚀变叠加组合主要为硅化——钾长石化——黄铁矿化组合、硅化——绿泥石化——黄铁矿化组合。该矿床属中高温热液斑岩型钼矿床,结合岩浆岩特征,成矿作用于与岩体关系密切,并可能受幔源岩浆混合作用的影响。     

利用ASTER资料估算黑河中游沙漠和绿洲地区夏季地表温度

利用美国宇航局地球观测系统EOS-Terra卫星所搭载高级空基热发射反射辐射计(ASTER)5个热红外通道遥感资料,并结合三种地表温度反演算法和可见近红外信息,估算2003年夏季黑河中游地区沙漠和绿洲景观下地表温度空间分布。分析发现三种方法估算的地表温度比较接近,且反演值与地面观测值较为一致,能够作为陆面过程研究输入数据。其中,估算的水体温度主要介于19.0~21.0℃,绿洲内农田温度分布于27.0~29.0℃,荒漠戈壁地表温度分布于40.0~60.0℃;在绿洲内,由植被覆盖度参数化比辐射率方法（Pv方法）所估算地表温度值最低,Alpha导出比辐射率方法(ADE方法)估算值最高,由温度比辐射率分离方法(TES方法)估算值介于二者之间;荒漠戈壁区域Pv方法地表温度估算值最高,ADE方法估算值最低,TES方法估算值仍然介于前两者之间;绿洲和荒漠戈壁均具有较大地表温度空间变率。利用有关比辐射率光谱库地物观测数据拟合出一个经验公式以获取地物宽通道比辐射率。分析计算表明,地物目标在较大地表环境温度变化范围内,利用地物宽通道比辐射率计算地表长波辐射最大绝对误差不超过8.0 W·m-2。