共查询到20条相似文献，搜索用时 62 毫秒
1.
蓬莱地区金矿床以石英脉型为主，其次是蚀变岩型；成矿条件与著名的玲珑金矿床相似。金主要产于黄铁矿和多金属硫化物石英脉中。流体包裹体研究表明，金矿床中主要存在两种类型的流体包裹体：CO2-H2O包裹体和中低盐度的NaCl—H2O溶液包裹体。CO2-H2O包裹体气相以CO2为主，可含少量CH4、H2S、CO。其中，黄铁绢英岩的石英中含有丰富的CO2-H2O包裹体，而黄铁矿石英脉和多金属硫化物石英脉中富CO2与富H2O的CO2-H2O包裹体共存。显微测温结果显示，黄铁绢英岩中的CO2-H2O包裹体的均一温度范围为230℃～300℃；而黄铁矿和多金属硫化物石英包裹体的均一温度为220℃-390℃，鉴于这些包裹体是从不混溶的CO2-H2O流体中捕获的，因此它们的温度下限220℃～250℃左右，应该看作是它们的形成温度。成矿早期流体为富含挥发份（流体密度0．92～0.985g／cm^3）、中低盐度（4．15％～5.23％NaCleqv）的流体：到主成矿期逐渐演化为温度升高，盐度变化范围大（1.02％～15.5％NaCleqv），水溶液以NaCl为主，气体仍以CO2为主，但可含少量的CH4、H2S、CO及有机质等的流体（流体密度0.32～0.99g／cm^3）；成矿期后的流体盐度、温度及CO2含量降至最低。本区矿床中石英的占δ^18O值变化在13.8‰-18.3‰，成矿流体的占δ^18O值在4、9‰-10.9‰之间，流体包裹体中占D变化范围很小，从-78‰变化到-101‰，主要集中在-78‰～-88‰之间。由此表明成矿流体以岩浆水为主，伴有大气降水的参与。在主成矿期成矿流体表现出明显的多期、多来源特征。温度降低和流体不混溶是导致金等成矿元素沉淀和富集的重要机制。 相似文献
2.
西秦岭造山带内的甘肃阳山金矿是我国最新发现的规模最大的金矿床。矿床受EW韧脆性剪切带控制，赋矿围岩为泥盆系碳质碳酸盐-千枚岩-板岩和侵入其中的花岗斑岩脉。流体成矿过程包括：形成石英-绢云母-黄铁矿组合的早阶段，形成石英-黄铁矿-毒砂和石英-毒砂-黄铁矿以及石英-碳酸盐-辉锑矿-自然金组合的主戍矿阶段，形成碳酸盐-石英网脉的晚阶段。早阶段流体包裹体以含CO2包裹体为主，CO2含量为7．3％-21．5mol％，均一温度集中于270℃～300℃，盐度〈3wt．％NaCleqv；主阶段发育纯CO2包裹体、水溶液包裹体和少量含CO2包裹体，均一温度集中于210℃～270℃，盐度集中在〈2wt，％NaCleqv和3～5wt，％NaCleqv两个范围；晚阶段只发育水溶液包裹体，均一温度集中在160℃-210℃，盐度〈3wt．％NaCleqv。主阶段流体包裹体类型的多样性、相似的均一温度和流体盐度的双峰特征均指示流体沸腾现象的存在，其流体包裹体捕获温度为210℃～375℃，压力为85～222MPa；赋矿断层的阀门式活动导致主阶段流体系统交替于静岩和静水压力之间，成矿深度为8．5km左右，成矿流体系统发育在早侏罗世大陆碰撞造山过程。矿床地质特征类似于卡林型金矿，但赋存于蚀变花岗斑岩中矿体既非造山型，也不同于卡林型，成矿流体具造山型矿床特征。因此，阳山金矿可能代表一种新的金矿类型，建议称为“阳山型金矿”。 相似文献
3.
玲珑金矿位于胶东半岛招．掖成矿带东部，是我国典型的超大型含金石英脉型金矿。成矿过程可划分为早、中、晚三个阶段，金主要在中阶段沉淀。早阶段流体包裹体为纯CO2型（LCO2＋VCO2〉90％）和富CO2型（10％≤LCO2＋VCO2≤90％），中阶段为纯CO2型、富CO2型、富H2O型，晚阶段为水溶液包裹体。从早到晚，包裹体均一温度分别集中在240℃～360℃、220℃-360℃、180℃-260℃和80℃-180℃，盐度分别集中在3．4％-10．4％、3．0％-10．2％、4．0％-14．6％和2．4％-5．0％NaCleqv；早、中阶段流体盐度随温度降低而升高。中阶段第一世代石英中大量水溶液包裹体和富CO2包裹体共生，指示流体强烈沸腾。从早到晚，流体包裹体的变化记录了成矿流体性质和构造环境的演化。早阶段石英中沿X型节理发育面型包裹体群，既记录了石英脉遭受的剪切变形事件，又记录了同构造流体作用。而充填于张性裂隙的黄铁矿为主的多金属硫化物．石英组合则表明主成矿期构造环境由压性向张性转化，成矿流体系统减压沸腾、逐步开放，并导致金等成矿物质大量沉淀。结合区域构造演化和成矿时间，认为玲珑金矿成矿系统发育在应力场由挤压向伸展转换的构造背景，流体压力变化滞后于构造应力场变化，流体成分以低盐度、富CO2为特征，应属典型的造山型金矿系统。 相似文献
4.
内蒙古白乃庙铜金矿床位于华北板块北缘增生型造山带，石英脉型和蚀变岩型矿体受EW向韧．脆性剪切带控制。成矿过程分为三个阶段：旱阶段石英-黄铁矿，乳白色石英和粗粒黄铁矿变形、破碎；中阶段多金属硫化物充填胶结旱阶段变形、破碎的石英角砾和黄铁矿裂隙；晚阶段为石英-碳酸盐细脉，穿切早中阶段脉体和矿物组合。冷热台显微测温结果显示．旱阶段石英中原生流体包裹体的均一温度为248℃～380℃，盐度为4．34％～6．59％，次生包裹体均一温度为180℃～260℃．盐度为3，23％～4．18％NaCleqv；中阶段石英中原生包裹体的均一温度变化范围为215℃～241℃，盐度为2．90％～4．18％NaCleqv，与旱阶段次生流体包裹体一致；晚阶段石英细脉和方解石中的流体包裹体均一温度为137℃～181℃，盐度为0．50％～2．00％NaCleqv。激光拉曼测试结果表明，流体包裹体气相成分为CO2、CH4和N2。成矿流体为低盐度、低密度、富CO2的流体，当这种流体到达剪切带时，由于压力骤然降低发生以CO2逸失为特征的沸腾作用，导致成矿流体过饱和，成矿物质快速沉淀下来形成矿床。白乃庙铜金矿床成矿流体及矿床地质特征与造山型矿床一致，确证了造山型铜矿的存在并提供了实例。 相似文献
5.
对瑶岗仙石英脉型钨矿床的石英、萤石和夕卡岩型钨矿床中石榴石流体包裹体的岩相学特征研究表明，与成矿有关的包裹体主要有三类：富液相、富气相和含子晶的多相包裹体。脉型钨矿床中石英包裹体均一温度范围为180℃-300℃，盐度O．88—6．45wt％NaCleqv；矽卡岩型钨矿床中石榴石包裹体的均一温度范围为190℃～300℃，盐度0．1～8．95wt％NaCleqv；成矿溶液的密度为0．81～0．89g／cm^3．表明形成这两种类型矿床的成矿流体均属于中温、低盐度、低密度的流体；成矿压力为120～160MPa，成矿深度约为7—9km，因此该矿床是在中高压力、中深成条件下形成的。激光拉曼探针分析表明，石英中包裹体的气相成分比石榴石中的更富含CH4、CO2和H2O等挥发份，说明流体是一种介于岩浆与热液之间的过渡性流体，具有上部偏液、下部偏浆的特点。由于该区自燕山期以来软流圈上隆，岩石圈经历了强烈的伸展、减薄作用和壳幔相互作用，而C-H还原性组分的增加，指示流体很可能来自于深部的地幔过渡带或者软流圈。 相似文献
6.
造山型金矿的成矿作用与H20-CO2流体有着密切的联系。然而对阿尔泰山南缘和穆龙套金矿的流体包裹体研究表明，无水的CO2-CH4流体在中亚成矿域中一些金矿床中具有同样重要意义。阿尔泰山南缘萨热阔布金矿包裹体的Xch4达0.20～0.23，穆龙套金矿的XCH4为0.07～0.23。CH4扩大了流体不混溶的范围，有利于对Au的富集沉淀。CO2流体在Au成矿中的重要作用至少包括了三方面的意义，即：缓冲流体PH值范围、提高流体中的Au含量并使其维持与还原硫的络合作用进行迁移；扩大超临界流体的温度范围；增加流体不混溶的区域。CH4的加入扩大了流体不混溶的范围，有利于对Au的富集沉淀。 相似文献
7.
对云南元阳县大坪大型金多金属矿床矿脉地质特征、流体包裹体和稳定同位素的研究表明，矿区内大量的矿脉是叠加成矿的产物，空间上具有并置、侧列（现）、再现等复杂关系，成矿可分石英．黄铁矿（主要形成金矿化）和石英．方铅矿（主要形成铜铅银矿化，并叠加有金矿化）两个阶段共7个亚阶段。石英-黄铁矿阶段流体包裹体以个体小，数量多。杂乱分布为特征，以二相气液包裹体为主，均一温度变化区间为165℃～393℃，平均258℃；流体密度为0．648—0．7984g／cm^3，盐度变化为13，72％～18．96％NaCleqv，平均17．13％NaCleqv，捕获压力为64MPa左右。流体为含CO2的NaCl-H2O体系，在成分上相对富集Na^＋、Cl^-、CH4和N2、NO3^-等组分，从早到晚，具有Na^＋、Ca^2＋、SO4^2-略有升高，而K^＋有所降低的趋势。石英方铅矿阶段流体包裹体大小混杂，杂乱分布或呈线性排列，以CO2包裹体为主，并有二相气液和少量单相包裹体。均一温度177℃～372℃，平均284℃，流体密度为0，7413～O．9518g／cm^3，盐度变化为10．86％～21．26％NaCleqv，平均14．16％NaCleqv，捕获压力为60MPa左右。流体属为NaCl-H2O-CO2体系，在成分上以相对富集Na^＋、K^＋、SO4^2-为特征，部分脉体的流体包裹体中还含有一定量的Ca^2＋、Mg^2＋等离子。矿区不同（亚）阶段矿石氧同位组成总体变化较小（2.65‰～6.0‰），氢同位素组成变化较大（-120％～-40‰），其中石英-黄铁矿阶段H、O同位素组成变化均较小，以岩浆源为主，而石英．方铅矿阶段氢同位素组成变化较大，表明有新的流体加入，但也以深源流体为主；石英-方铅矿阶段一个铁白云石的δ^13C值为-4．81％o，而石英．黄铁矿阶段晚期方解石碳同位素组成变化为-2．79‰～-4.34‰，平均-3．75‰。不同矿脉黄铁矿、方铅矿的硫同位素组成变化范围为0．3‰-4.4‰，其中石英-黄铁矿阶段为0.3‰～4．4‰，石英-方铅矿阶段为0.5～4.3‰，总体上与深源（地幔）碳、硫同位素组成基本一致。综合对比研究认为，大坪金多金属矿床为源于深部的多源成矿热液在同一容矿空间充填的结果，叠加成矿作用与区内长期的岩浆活动密切相关。矿床为中-高温热液硫化物．石英薄脉型金多金属矿床。 相似文献
8.
额尔古纳成矿带是中国东北重要的银、铅、锌、铜、钼多金属成矿带，它位于蒙古-鄂霍茨克造山带的东南缘。最近，额尔古纳成矿带西北部发现了砂宝斯、老沟、小伊诺盖沟等金矿床和一些金矿点。这些金矿受洛古河-二根河韧性剪切带和额尔古纳河韧性剪切带控制，矿体常赋存于韧性剪切带的次级张扭性断裂构造中。矿石中硫化物含量一般不超过3％，且硫化物以黄铁矿为主。流体包裹体有气液两相、含CO2三相和纯CO2包裹体3种类型。气相成分以H2O、CO2和N2为主，含少量H，S、CH4为特征。流体包裹体的盐度低，介于2.06～8、54％NaCleqv之间。老沟金矿流体包裹体均一温度介于171℃～452℃之间，平均295℃，小伊诺盖淘金矿包裹体均一温度为169℃～493℃，平均亦为295℃，均属中温热液矿床。老淘金矿成矿压力为61～122MPa，平均82MPa；小伊诺盖沟金矿成矿压力为38～172MPa，平均93MPa。前者成矿深度介于6～9km，平均7km；后者成矿深度为4～11km，平均8km。上述金矿床的地质-地球化学特征与世界造山型金矿类似，形成于蒙古-中朝板块与西伯利亚板块之间的陆-陆碰撞造山作用。 相似文献
9.
对夹皮沟地区夹皮沟群变质岩一斜长角闪岩及夹皮沟和二道沟金矿金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：金矿石中发育水溶液相、含CO2相及CO2相等三类包裹体，成矿过程中，流体经历了NaCl-H20．CO2体系的不混溶作用，各类包裹体均一温度157．2℃～440℃，盐度1．8％～11．6％NaCleqv，流体密度0．54—0．96g／cm^3；变质岩中以发育含子矿物多相包裹体为主，其均一温度为260℃～480℃，盐度为36．5％-54．8％NaCleqv，流体密度为1．06—1．17g／cm^3，反映了变质流体为一中温、高盐度、高密度均匀NaCl-H20热液体系。成矿流体与变质流体存在明显差异，表明该区金矿床成矿流体并非来自太古代变质热液。结合新近的流体包裹体氢、氧同位素分析结果和测年数据，认为本区金矿成矿流体以来自岩浆热液为主，矿床成因属中生代岩浆热液矿床。 相似文献
10.
招-平断裂是胶东招掖金矿带的主要控矿断裂，其上盘金矿床受NE向断裂构造控制，赋矿围岩为胶东群变质岩，金矿化以含金硫化物石英脉为主。通过首次对招远灵雀山金矿床富金石英脉石英流体包襄体Rb-Sr等时线年龄的测定，获得116±23Ma成矿年龄。从而说明招-平断裂带上盘金矿大规模成矿期发生于早白垩世的构造体系转折期。对富金石英脉石英流体包襄体同位素特征研究表明。该地区成矿热液均以幔源为主，具有与招掖金矿带其它金矿类似的成矿热液系统。由此可以看出招．平断裂带上盘也具有良好的成矿条件。 相似文献
11.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
13.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
15.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
16.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
17.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
18.
Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
19.
Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
20.
《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献