辽宁卧龙泉金矿地质特征及成因     

黄海波康志勇  温晓春 《地质找矿论丛》2005,20(8):71-74

文章通过成矿物质来源、成矿作用与岩浆岩及构造的关系、成矿阶段的划分等方面的研究，认定卧龙泉金矿为多阶段、多成因、多来源的中-低温热液矿床。进而确定了卧龙泉金矿床的成矿模式。  相似文献   

Characteristics of Gold Mineralization at the Ciurug Vein, Pongkor Gold-Silver Deposit, West Java, Indonesia     

Syafrizal    Akira Imai    Yoshinobu Motomura  Koichiro Watanabe 《Resource Geology》2005,55(3):225-238

Abstract. The Pongkor Gold‐Silver Mine, Bogor district, West Java, is approximately 80 km southwest of Jakarta. The gold and silver mineralization in the area is present in a deposit consisting of an epithermal vein‐system named individually as the Pasir Jawa, Gudang Handak, Ciguha, Pamoyanan, Kubang Cicau, and Ciurug veins. In the area studied, rocks of basaltic‐andesitic composition are dominated by volcanic breccia and lapilli tuff, with andesite lava and siltstone present locally. The hydrothermal alteration minerals in the Ciurug area are typical of those formed from acid to near‐neutral pH thermal waters, where the acid alteration is distributed from the surface to shallow depth, while the near‐neutral pH alteration becomes dominant at depths. The Ciurug vein shows four main mineralization stages where each discrete stage is characterized by a specific facies; these are, from early to late: carbonate‐quartz, manganese carbonate‐quartz, banded‐massive quartz and gray sulfide‐quartz facies. The major metallic minerals are pyrite, sphalerite, chalcopyrite and galena; they occur in almost each mineralization stage. Bornite was observed only in the southern part of the Ciurug vein at a depth of 515 m, and the occurrence of this mineral is reported here for the first time. Electrum and silver sulfides (mostly acanthite) are minor, whereas silver sulfosalts, stromeyerite and mckinstryite, and covellite are in trace amounts. The silver sulfosalts have compositional ranges of pearceite, antimon‐pearceite and polybasite. Most of the electrum occurs coexisting with other sulfide minerals, as inclusions in pyrite grains, with very little as inclusions in chalcopyrite or sphalerite. Gold grades within the Ciurug vein vary from 1.2 to hundreds of ppm, where the highest gold grade occurs in the latest mineralization stage in a thin sulfide band in vein quartz. Fluid inclusion microthermometry of calcite and quartz indicates deposition throughout the mineralized veins in the range from 170 to 230d?C and from low salinity fluids (predominantly lower than 0.2 wt% NaCl equiv.). Fluid inclusions occur with features of boiling.  相似文献   

江苏省县域城镇规模变动研究   总被引：2，自引：0，他引：2  

高珊  张小林 《地理与地理信息科学》2005,21(5):64-67,F0003

由于乡镇企业等集体经济的创业优势不再重现，江苏省小城镇发展需要反思和重新定位。以20世纪90年代江苏省县域城镇规模变动为研究对象，指出数量变化显著、等级分化加剧、区域分异明显等客观事实。针对行政干预过多、人口吸纳力不足、基础设施滞后、用地方式粗放、城建资金匮乏等问题，从制度、经济和社会结构角度分析影响县域城镇规模变化的动力机制，提出县域城镇发展需要制度创新、提升城镇功能、实行区域差异政策等。  相似文献   

胶东金青顶和大尹格庄金矿床花岗质围岩的蚀变地球化学研究   总被引：10，自引：5，他引：10  

凌洪飞  胡受奚  孙景贵  倪培  沈昆 《矿床地质》2002,21(2):187-199

研究了大尹格庄金矿床和金青顶金矿床的花岗质围岩及其恂变岩的主元素，微量元素和氧同位素等特征，结果表明郭家店花岗岩和金青顶花岗岩Nb,Ta,P,Ti相对亏损，εNd(t)值为-11.9-14.5，为前寒武纪地壳岩石熔融的产物，大尹格庄围岩蚀变较强，主要为沿断裂带发育的绢英岩化及深部的钾长石化，金青顶蚀变较弱，在绢英岩化和绢云母化蚀变过程中，两矿床Na2O和REE降低Au,Ag升高，金青顶变化幅度相对较小，热液带入的组分均为Au,Ag,As,Co,Cu,K2O等，在大尹格庄带入组分还包括Pb,Zn,Fe,SiO2。似伟晶状钾长石化均使两矿区K2O显著升高，Au和Ag略有程式高，其余组分降低，尤其轻稀土降低显著，引起大尹格庄矿床围岩发生绢英岩化和假伟晶状钾长石化的初始流体δ^18O值下限分别为3.3‰和4.4‰，以岩浆热液占主导；引起金青顶矿床围岩发生似伟晶状钾长石化和绢云母化的初始流体的δ^18O值下限分别为2.1‰和1.2‰，也以岩浆热液为主，但不排除有大气降水参与。  相似文献   

蚀变作用的多原岩系统及质量平衡   总被引：1，自引：0，他引：1  

张可清  杨勇 《地质科技情报》2002,21(2):61-64

介绍了造成岩石地球化学不均匀性的原因，主要有测量误差、闭合问题及岩石学方面的控制等。各有其不同的研究和解决方法。对于蚀变岩的多原岩系统，常用不相容高场强元素（HFSE）来描述岩石性质，用其作为监视器，可作出各相容元素（或成分）的分异线；用不活动元素蚀变线与分异线的产点来确定原始成分，并在此基础上进行蚀变岩质量变化的计算。  相似文献   

A Petrographic and Mineralogical Study of Volcanic Rocks from the Mayaxueshan Area, North Qilian Fold Belt, NW China     

HSU Ta-Wei  SHAU Yen-HongDepartment of Marine Resources  National Sun Yat-Sen University  Kaohsiung  China 《《地质学报》英文版》2002,76(1):15-30

The Ordovician volcanic rocks in the Mayaxueshan area have been pervasively altered or metamorphosed and contain abundant secondary minerals such as albite, chlorite, epidote, prehnite, pumpellyite, actinolite, titanite, quartz, and/or calcite. They were denoted as spilites or spilitic rocks in terms of their petrographic features and mineral assemblages. The metamorphic grades of the volcanic rocks are equivalent to that of the intercalated metaclastic rocks. This indicates that both the spilitic volcanic rocks and metaclastic rocks in the Mayaxueshan area have formed as a result of Caledonian regional metamorphism. We suggest that the previously denoted spilitic rocks or altered volcanic rocks should be re-denoted as metabasalts or metabasaltic rocks. The metamorphic grade of the volcanic rocks increases with their age: prehnite-pumpellyite facies for the upper part of the Middle Ordovician volcanic rocks, prehnite-pumpeilyite to lower greenschist facies for the lower part of the Middle Ordovician vol  相似文献   

Geoelectromagnetic Exploration For Natural Resources: Models, Case Studies And Challenges   总被引：6，自引：1，他引：6  

Maxwell A. Meju 《Surveys in Geophysics》2002,23(2-3):133-206

This paper presents a tutorial review of electrical and electromagnetic(herein collectively called geoelectromagnetic) methods as applied in the search for natural resources. First, the paper discusses the technical problems and advances in geoelectromagnetic methods in the last decade. A scheme for integrating electrical and electromagnetic depth sounding data is suggested.Then, for natural resources exploration, it focuses on three themes: (1) understandinggeological models of resource targets, their physical properties, and the development of conceptual geoelectromagnetic exploration models, (2) overview of geoelectromagnetic case studies in resourceexploration, and (3) outstanding challenges in exploration. For brevity, model development is restricted to groundwater, geothermal and hydrocarbon resources, metallic ore-bodies (exemplified byvolcanogenic massive sulphides, porphyry coppers, and epithermal and Archaean greenstone belt gold deposits) and diamonds. In the treatment of resource exploration in this paper, the unifying themeis that geochemical processes of weathering and hydrothermal alteration form clayey products that may render natural resource targets directly or indirectly detectable by their resistivity characteristics.Since hydrated clays are an important feature of most resource types and are major causes of low resistivity anomalies in geoelectromagnetic exploration, they may be taken as providing detectable marker horizons or pathfinders and a basis for developing a consistent investigative approachfor natural resources. However, it is recognised that no single resource model or standard approach may be universally applicable. Natural resource systems are inherently 3D and require large numbers of depth soundings at high station densities to image adequately. Thus, developing methodsof increasing the productivity of data acquisition, the development of better 3D software tools and lowering costs are seen as the major challenges facing the use of geoelectromagnetic methods for naturalresource exploration.  相似文献   

胶东金矿床围岩蚀变带内云母类矿物、矿物化学-多型系列及其找矿信息          下载免费PDF全文

Francesco P.Sassi  杨敏之 《地质找矿论丛》2001,16(2):73-80

对胶东15个金放床围岩蚀变带内30个云母类矿物的地质产状，空间分带，与矿化关系地质调查基础上，着重对各类型金矿床蚀变带内云母类矿物进行了单矿物提纯，矿物化学定量分析，物理性质鉴定，X光衍射分析，差热分析，红外吸收光谱分析，晶格常数计算，形成条件等方面的系统研究，确定了蚀变岩带内有9种云母类矿物，5个矿物化学－多型系列，新鉴定出5种云母类矿物，绿鳞石（Celadonite),铁绿鳞石（Ferian Celadonite)，铁铝绿磷石（Ferian-Alumino Celadonite)，铝绿鳞石（Alumino Celadonite)和伊利石（Illite)，总结了云母类矿物各系列的演化特征，查明了金矿床各蚀变－矿化带内所出现的云母类矿物晕，指出了各云母类矿物晕的找矿信息。  相似文献   

济阳拗陷第三纪玄武岩的氧同位素   总被引：2，自引：0，他引：2  

金莹  沈渭洲  蔡元峰  赵连泽  赵明  孔庆友 《高校地质学报》2001,7(3):363-367

研究了山东刘阳拗陷29个第三纪玄武岩样品的氧同位素组成。结果表明，这些玄武岩的全岩氧同位素组成变化明显，δ^18○值为6．3‰－12．2‰。其中，蚀变轻微的晚第三纪玄武岩的δ^18○值为6．3‰－7．9‰，与正常大陆玄武岩的值（5．0‰－7．4‰）相似；而蚀变明显的早第三纪玄武岩的δ^18○值为6．3‰－12．2‰，并且90％以上样品的δ^18○值都大于7．5‰。结合岩石学与岩石化学研究，是第三纪玄武岩δ^18○值不同程度升高是由低温雨水热液蚀变（碳酸盐化）作用造成的。  相似文献   

新疆北部陆相火山岩型金矿床的主要特征   总被引：1，自引：1，他引：1  

刘家远 《黄金地质》2001,7(3):1-7,T001

陆相火山岩型金矿目前是新疆最为重要也最富有特色和发展前景的金矿新类型。与金矿有关的火山岩，主要是一套以玄武岩－安山岩－流纹岩及其相应火山碎屑岩组合为特征的陆相火山岩。新疆北部存在两期（华力西中期和中晚期－晚期）陆相火山岩，相应发育两期金矿化。矿床地质和地球化学的一系列特征表明，该类金矿是与陆相火山岩密切相关，形成于岛弧或活动大陆边缘型挤压造山环境及近地表条件下的浅成低温热液金矿床。成岩成矿物质具源自上地幔或下部地壳的深源特征。  相似文献