Mineralization Styles and Genesis of the Yinkeng Au-Ag-Pb-Zn-Cu-Mn Polymetallic Orefield, Southern Jiangxi Province, SE China: Evidence from Geology, Fluid Inclusions, Isotopes and Chronology

The Yinkeng orefield in Yudu County,Jiangxi Province,SE China,is a zone of concentrated Au-Ag-Pb-Zn-Cu-Mn polymetallic ores.Based on summing up basic geology and ore geology of the orefieid,the polymetallic deposits in the orefield have been divided into seven major substyles according to their occurring positions and control factors.The ore-forming fluid inclusion styles in the orefield include those of two-phase fluid,liquid CO2-bearing three-phase and daughter mineral-bearing multi-phase.The homogenization temperatures range from 382° to 122℃,falling into five clusters of 370° to 390°,300° to 360°,230° to 300°,210° to 290° and 120° to 200°,and the clusters of 300° to 360°,230° to 300° and 120° to 200° are three major mineralization stages,with fluid salinity peaks from 4.14% to 7.31%,2.07% to 7.31% and 0.53% to 3.90%,respectively.The ore-forming fluids are mainly type of NaCl-H2O with medium to high density （0.74-1.02 g/cm3）,or CO2-bearing NaCl-H2O with medium to low density （0.18-0.79 g/cm3）.The fluid salinity and density both show a decline tendency with decreasing temperature.According to the measurement and calculation of Hand O-isotopic compositions in the quartz of the quartz-sulfide veins,δDV-SMOW of the ore-forming fluid is from-84‰ to-54‰,and δ18OV-SMOW of that is from 6.75‰ to 9.21‰,indicating a magmatic fluid.The δ34SV-CDT of sulfides in the ores fall into two groups,one is from-4.4‰ to 2.2‰ with average of-1.42‰,and the other from 18.8‰ to 21.6‰ with average of 19.8‰.The S-isotopic data shows one peak at-4.4‰ to 2.2‰ （meaning-1.42‰） suggesting a simple magmatic sulfur source.The ore Pbisotopic ratios are 206pb/204pb from 17.817 to 17.983,207pb/204pb from 15.470 to 15.620 and 208pb/204pb from 38.072 to 38.481,indicating characteristics of mantle-derived lead.The data show that the major ore deposits in the orefield have a magmatic-hydrothermal genesis and that the SHRIMP zircon age of the granodiorite porphyry,closely related to the mineralization,is 151.2±4.2 Ma （MSWD =1.3）,which can represent the formation ages of the ores and intrusion rocks.The study aids understanding of the ore-forming processes of the major metallic ore deposits in the orefield.

Application of Fluid Inclusions in Tectonic Geology

The release of thermal fluids is expected during tectonic movement. These thermal fluids may be trappedby minerals (newly formed or recrystallized)to form fluid inclusions. The aim of this paper is to discuss thetectonic relations between the North China Platform and the Qinling Geosyncline based mainly on the fluidinclusion data. Some preliminary conclusions have been drawn as follows:1. Recognized between the platform and tbe geosyncline are several tectonic belts, each of whch hasdifferent characteristics with respect to fluid inclusions.2. Various tectonic beits are bounded by the fault, on both sides of which fluid inclusions found areconsiderably different.3. Research on fluid inclusions provides further information on the history of tectonic evolution of theNorth China Platform and the Qinling Geosyncline.This work is an initial attempt to the study of tectonic geology in terms of fluid inclusion data.

Ore-Forming Conditions and the Process of Gold Mineralization of Wendeng Gold Deposit, Shandong──Application of Cathodo-Luminescence in Fluid Inclusion Studies

The Wendeng gold deposit is located 30 km northwest of Wendeng City,Shandong Province, occurring in a brecciated alteration zone in the foot wall of the NNE-striking fault(F1). It consists of quedz, pyrite, specularite, potash feldspar, sericite,carbonates and chlorite hosted in Proterozoic biotite-plagiclasee gneiss.Three generations of quartz are recognized based on cathodoluminescence and micromorphology. Systematic studies sf fluid inclusions provide data to establish P-T-V-Xrelations for the fluid evolution in mineralization procee. It is concluded that the ore-forming solution was evolved from meteoric water through thermal events during Mesozoictectonics. The precipitatfon of gold was related to two boiling events.

Hydrocarbon Generation, Migration, and Accumulation in the Eocene Niubao Formation in the Lunpola Basin, Tibet, China: Insights from Basin Modeling and Fluid Inclusion Analysis

The Eocene Niubao Formation is the primary research target of oil exploration in the Lunpola Basin.Crude oil was extracted from Well Z1 on the northern margin of the basin in 1993.In this study,an integrated evaluation of the source rock geothermal,and maturity histories and the fluid inclusion and fluid potential distributions was performed to aid in predicting areas of hydrocarbon accumulation.Due to the abundance of organic matter,the kerogen types,maturity,and oil-sources correlate with the geochemical data.The middle submember of the second member of the Niubao Formation(E2n^2-2)is the most favorable source rock based on the amount of oil produced from the E2n^2-3and E2n^3-1reservoirs.One-and twodimensional basin modeling,using BasinMod software,shows that the E2n^2-2source rock started to generate hydrocarbon at 35-30 Ma,reached a maturity of Ro=0.7%at 25-20 Ma,and at present,it has reached the peak oil generation stage with a thermal maturity of Ro=0.8%to less than Ro=1.0%.By using fluid inclusion petrography,fluorescence spectroscopy,and microthermometry,two major periods of oil charging have been revealed at 26.1-17.5 and 32.4-24.6 Ma.The oil accumulation modeling results,conducted by using the Trinity software,show a good fit of the oil shows in the wells and predict that the structural highs and lithologic transitions within the Jiangriaco and Paco sags are potential oil traps.

Study on Hydrological Engineering Geological Conditions and Anti- leakage Measures

With the continuous development of economy and society, people's ability to transform society has been improved. To break the constraints of hydrological and climatic conditions, some hydrology and water conservancy projects were constructed to meet the needs of human activities. In the construction of hydrological engineering, geological conditions are first surveyed to determine whether there are significant geological structure problems, in order to enhance the stability of hydrological engineering and reduce the probability of hydrological engineering leakage.

内蒙古格鲁其堆山铅锌矿床地质特征及流体包裹体研究

格鲁其堆山铅锌矿床是近年来新发现具有较大找矿潜力的铅锌矿床,位于得尔布干断裂中段西侧,矿化体赋存于额尔古纳河组、佳疙疸组等地层中,铅锌矿化与闪长岩、闪长玢岩具有密切的生成关系,受北东向断裂控制。热液期成矿作用大致可划分为黄铁矿±方铅矿-石英阶段(Ⅰ),方铅矿、闪锌矿±黄铜矿-石英阶段(Ⅱ),少硫化物-碳酸盐阶段(Ⅲ)。流体包裹体研究结果表明,石英中仅发育气液两相包裹体,成矿流体为简单中低温、低盐度的NaCl-H2O热液体系,早期成矿流体应以岩浆热液为主。主成矿阶段(Ⅱ)完全均一温度峰值集中在200℃~250℃,平均值230.2℃,盐度峰集中在2%~6%,捕获时静水压力集中在14.00~25.27 MPa,估算成矿深度为1.40~2.53 km。综合分析认为,格鲁其堆山铅锌矿床与中酸性浅成侵入体具有密切时空关系,成因类型属中温热液脉型。

Hydrological response characteristics of landslides under typhoon-triggered rainstorm conditions

Many landslide disasters,which tend to result in significant damage,are caused by typhoon-triggered rainstorms.In this case,it is very important to study the dynamic characteristics of the hydrological response of landslide bodies since it enables the early warning and prediction of landslide disasters in typhoon periods.To investigate the dynamic mechanisms of groundwater in a landslide body under typhoon-triggered rainstorm conditions,the authors selected the landslide occurring in Zhonglin Village,Wencheng County,China(also referred to as Zhonglin Village landslide)as a case study.The transient seepage field characteristics of groundwater in the landslide body were simulated with two different rainfall models by using the finite element method(FEM).The research results show that the impact of typhoon-triggered rainstorms on landslides can be divided into three stages:(i)Rapid rise of groundwater level;(ii)infiltration of groundwater from the surface to deeper level,and(iii)surface runoff erosion.Moreover,the infiltration rate of groundwater in the landslide body is mainly affected by the intensity of typhoon-induced rainfall.It can be deduced that higher rainfall intensity leads to a greater potential difference and a higher infiltration rate.The rainfall intensity also determines the development mode of landslide deformation and destruction.

New high-resolution 2D seismic imaging of fluid escape structures in the Makran subduction zone,Arabian Sea

Seabed fluid escape is active in the Makran subduction zone,Arabian Sea.Based on the new highresolution 2D seismic data,acoustic blanking zones and seafloor mounds are identified.Acoustic blanking zones include three kinds of geometries:Bell-shaped,vertically columnar and tilted zones.The bellshaped blanking zone is characterized by weak and discontinuous reflections in the interior and upbending reflections on the top,interpreted as gas chimneys.Vertically columnar blanking zone is interpreted as side-imaged gas chimneys associated with focused fluid flow and topped by a seafloor anomaly expressed as a localized reflection discontinuity,which may together serve as a vent structure.Tilted acoustic blanking zone could be induced by accretionary thrust activity and rapid sedimentation surrounding slope.Seafloor mounds occur at the sites of bell-shaped acoustic blanking zone and may be associated with the material intrusion.Bottom simulating refectors(BSRs)are widely distributed and exhibit a series of characteristics including diminished amplitude,low continuity as well as local shoaling overlapping with these acoustic blanking zones.The large amount of gases dissociated from the gas hydrates migrated upwards and then arrived at the near-seafloor sediments,followed by the formation of the gas hydrates and hence the seafloor mound.

黄河中游沁河流域环境敏感性分析评价

【研究目的】沁河流域作为黄河流域重要的一级支流,也是黄河流域的重要水土保持功能区,当前面临着水环境遭受破坏以及土壤侵蚀这两个敏感环境问题,环境敏感性评价是用于表征外界干扰对自然生态系统可能造成结果的重要指标,对区域建立生态涵养区的环境政策以及有效进行区域生态建设具有重要作用。【研究方法】根据研究区面临的不同环境地质问题选取了层次分析法(AHP)与RUSLE模型的评价方法以及相关因子,并结合GIS空间数据技术强大的空间分析功能,将图形处理与空间数据运算结合,生成敏感性评价图,评价结果直观,为环境敏感性分析提供了技术支持。【研究结果】针对沁河流域的环境敏感性进行评价,并划分为轻度、中度、高度、极度4类敏感区域,进行统计分析,得出流域内以中、高度敏感区域占比最大,分别占总面积的33.43%、48.56%,同时以各支流流域为依托,针对各类敏感区域的主要环境问题,对其环境现状产生的原因及改善方法提出了相应的调整方案。【结论】依据各区域环境现状及敏感性程度提出了沁河全流域的生态环境保护修复思路,构建一个山地生态系统和平原生态系统有机结合的生态网络格局,致力于改善沁河流域的生态环境现状。

豫西杨山萤石矿床成因:萤石稀土元素组成和流体包裹体热力学制约

杨山萤石矿床是豫西栾川地区一处大型花岗岩容矿型矿床,其成矿期次和成矿流体特征研究的不足长期制约着对萤石淀积机理和区域成矿规律的深化认识。本文基于杨山矿床萤石的稀土元素及流体包裹体研究,阐释了成矿物质来源、成矿流体属性及矿床成因。第Ⅱ阶段萤石的ΣREE含量为22.61×10^(-6)~287.94×10^(-6),LREE/HREE比值为0.64~5.24,具Eu负异常(δEu=0.50~0.92)和Ce负异常(δCe=0.88~1.06)。随成矿深度的增大,萤石ΣREE减小,LREE/HREE和La_(N)/Yb_(N)增大,δEu和δCe无明显变化,指示总体成矿先后顺序为地下深部至地表浅部,且垂向上氧逸度较稳定。从紫色萤石到绿色萤石,ΣREE增大,LREE/HREE和La_(N)/Yb_(N)减小,δEu和δCe增大,表明萤石具有重新活化和重结晶的趋势。萤石的流体包裹体以气液两相为主,均一温度集中于80~155℃,盐度(NaCl_(eqv.))集中于0.3%~6.3%。综合分析认为,杨山萤石矿床成矿流体以岩浆水和大气降水混合型为主,属低温、低盐度和低密度的NaCl-H_(2)O流体体系;矿床可归属于中低温、低盐度热液型矿床。萤石的稀土元素和流体包裹体特征综合分析表明,萤石的沉淀可能受水-岩反应控制。

岩土工程地质勘查中水文工程地质问题研究

为深入探究水文工程地质问题,以某工程为例,指出其中存在的问题,提出水文工程地质钻探与地质勘查施工技术,明确地区矿区储量及上部含水层的水文地质环境,展开数据收集与分析,对矿层厚度及顶底板位置情况进行研究,获得了良好的应用效果,能够保障工程施工质量与安全,可为类似工程开展提供一定参考。

岩土工程地质勘查技术与质量控制研究

分析岩土工程中的地质勘查技术与质量控制措施。明确地质勘查技术在岩土工程项目中的应用原则;结合实际工程案例,梳理具体的地质勘查流程以及质量控制要素。通过地质勘查,可以获得岩土工程所在地区的地质构成情况、水文情况、历史上的地震发生情况以及地震的强度等信息。围绕这些信息进行综合考量,可提高岩土工程施工方案的编制科学性、可行性,是现代岩土工程中不可或缺的重要环节。

基于矿山水工环的地质灾害危险性研究及防治对策分析

研究了矿山水工环的地质灾害危险性及治理措施,分析了地下水、地震、滑坡、泥石流、塌陷等主要类型地质灾害的危险性,并针对地质灾害成因,提出了采取针对性的预防与治理措施,坚持预防为主、治理第一的基本原则,绿色、安全、高效地开采矿产资源,以避免重大生产安全事故的发生。

矿山水文地质工程钻探关键技术关键点分析

矿山水文地质工程钻探施工难度大,技术要求高,为保障矿山水文地质工程钻探施工的高效开展,需要把握关键技术与关键点。本文从矿山水文地质工程钻探施工设计与设备选择、地层压力预测、孔内事故预防与处理等方面入手,分析总结矿山水文地质工程钻探关键技术关键点,希望对提升矿山水文地质工程钻探施工质量、效率与安全等有所帮助。

矿山水工环地质灾害危险性及治理措施

随着我国社会经济的不断发展,人们对于矿产资源的需求越来越多,地质灾害资源和环境问题也越来越多地受到社会各界的关注,因此必须加强对矿山开采工作的研究和分析,提高矿山开采的安全性,从而降低对地质环境的不利影响.本文主要阐述了矿山水工环地质灾害危险性评估的主要因素和矿山水工环地质灾害的类型,分析了当前矿山水工环地质灾害危险性评估存在的问题,并提出了相关的治理措施,以期为生态环境的可持续发展提供一分助力.

生态环境保护大背景下水工环地质勘察

随着我国经济的进步和发展,在当今的社会发展背景下,相关单位在开展水工环地质勘察工作的过程中,应对原有观念进行优化和完善,采取各项措施有效提升水工环地质勘察工作的水平。该文就水工环地质勘察在环保大背景下的工作重点进行探讨,为业内提供有益参考。

水工环地质勘察技术与应用初探

地质勘察以及地质研究工作中,技术人员所能够应用的技术展览展现出创新化的发展趋势。并且,在全新的时代背景下,地质学方面的研究也逐渐突破了传统问题的局限,形成了较多的发展成果。但客观分析来看,现阶段我国经济在发展过程中,仍会对能源形成过度的需求,甚至呈现出逐年增加的情况。这一情况的存在必然会引发不良影响,所以需要从水工环地质勘察工作入手,以先进的技术更加全面地把控地质环境,降低需求对于资源形成的破坏。

栾川上房沟钼矿床流体包裹体特征及其地质意义

上房沟钼矿床位于栾川断裂带北侧的华北克拉通南缘,矿体赋存于晚元古代栾川群碎屑岩-碳酸盐建造中。钼成矿经历了早、中、晚3个阶段:早阶段为钾长石-石英-辉钼矿-黄铁矿组合,中阶段为石英-辉钼矿-多金属硫化物组合,晚阶段以方解石-石英-萤石脉为特征。流体包裹体可划分为富/含CO_2型、含子矿物型和NaCl-H_2O型3类。早、中成矿阶段发育较多CO_2-H_2O型和含子晶型包裹体,晚阶段为NaCl-H_2O型包裹体。早阶段流体具有高温(320℃～500℃)、高盐度(31.75～66.75wt%NaCl eqv.)、富CO_2的特点,显示浆控高温热液矿床的特征;中阶段流体具有中温(190℃～400℃)、中等盐度(2.07～12.85 wt%NaCl eqv.,个别超过30 wt%NaCl eqv.)、富/含CO_2特点;晚阶段为中低温(160℃～260℃)、低盐度(～4.8 wt%NaCl eqv.)、贫CO_2的NaCl-H_2O体系。早、中阶段流体沸腾作用强烈,造成CO_2不断逸失、流体氧化性降低、成矿物质大量沉淀,是成矿的重要机制。

成岩成矿深度:主要影响因素与压力估算方法

成岩成矿深度是金属矿床成矿地质体的重要空间参数,受到地质构造、岩浆岩、围岩等诸多因素的影响。初步讨论了成矿深度的主要影响因素:岩浆因素和构造因素。内生矿床,特别是岩浆热液矿床的形成深度与岩浆作用的深度有关,岩浆侵位深度限定了矿床形成深度的下限,而岩浆上升和侵位过程中分异出的热液的深度直接决定了成矿深度。构造变形直接控制了多孔介质的渗透率,渗透率制约了流体的流动,成矿流体运移和就位则直接与成矿深度相关联。还阐述了成岩成矿深度(压力)的估算方法,以流体包裹体温压计为主,结合其它矿物地质温度计和压力计,并综合考虑成矿地质构造、岩浆岩、围岩等因素,才能获得合理和符合地质实际的成矿深度,为找矿勘查提供经得起检验的深度参数。

云南巍山——永平矿集区流体地质填图的理论与实践

流体地质填图是一种全新的地质调查及找矿方法。本次研究选择云南巍山—永平矿集区进行流体地质填图试验,研究了矿集区的控矿地质要素、各种主要的矿床(点)特征、成矿流体子系统及流域、流体的盐度与均一温度、流体的气液相成分、微量元素含量、稳定同位素特征及成矿流体的浓集中心。得到的流体地质图基本反映了本区成矿流体的性质与状态,反映了两个成矿流体子系统的基本特征,圈定了2个成矿流体子系统的流域范围及7个成矿流体浓集中心。这些浓集中心与已知矿化点分布、化探异常及有利的地质条件基本吻合,成为该区进一步找矿预测的重要依据之一。本项目的实践表明,流体地质填图不失为一种有效的找矿手段。