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1.
安徽和县香泉独立铊矿床的地质地球化学特征及成因探讨 总被引：7，自引：2，他引：7
安徽和县香泉铊矿床位于长江中下游成矿带北侧的皖东地区,是目前为止发现的罕见独立铊矿床。和县地区位于扬子板块、华北板块和大别造山带之间的过渡带,区内无岩浆岩出露。矿床的赋矿围岩为奥陶系下统仑山组微晶灰岩、泥灰岩和泥岩,主要控矿构造为断裂和褶皱。矿床主要由一个矿体组成,矿体总体上为似层状和透镜状,分布与地层走向大体一致。矿床中铊高度富集,黄铁矿是铊的主要载体矿物,铊主要以类质同象形式替代铁进入黄铁矿晶格,其次以纳米级、次纳米级铊矿物颗粒形式产出。矿床的围岩主要蚀变类型有萤石化、重晶石化、硅化和碳酸盐化等。矿床的地质地球化学特征研究表明,铊矿床的形成经历了两个成矿期,即海底热水沉积成矿期和低温热液改造成矿期。奥陶纪海底热水形成含铊黄铁矿建造,早白垩纪低温成矿流体对黄铁矿建造进行叠加改造,并使铊进一步活化富集。香泉铊矿床的发现和研究表明,分散元素铊不仅可以富集形成伴生型多元素矿床,还可以形成单一元素的独立铊矿床。 相似文献
2.
分散元素铊成矿作用的相关研究近年来已经取得了重要进展,但矿床中铊的赋存状态研究仍有待深入.香泉独立铊矿床位于长江中下游成矿带北侧的皖东地区,该矿床中铊的赋存状态研究对拓展铊元素成矿研究具有重要意义.本文通过矿相学、微量元素地球化学、电子探针分析和X射线粉晶分析等方法,确定了香泉铊矿床中黄铁矿是铊的主要载体矿物.铊在黄铁矿中主要以类质同象形式替代铁进入黄铁矿晶格,其次以纳米级、次纳米级铊矿物颗粒形式产出. 相似文献
3.
长江中下游地区首例低温独立铊矿床的Sm Nd同位素定年及其意义 总被引：1，自引：0，他引：1
为了确定长江中下游地区首例独立铊矿床—安徽和县香泉铊矿床的热液改造期成矿时代,对矿床中早晚两阶段10件萤石样品进行了SmNd同位素测定,得出早、晚两阶段萤石的等时线年龄分别为131.6±3.0Ma和79±11Ma。结合矿床地质地球化学特征,认为该独立铊矿床低温热液成矿作用发生在晚燕山期,并在燕山期末发生过一期热(泉)活动的叠加。该矿床的发现指示在长江中下游地区存在晚燕山期低温成矿事件和可能的低温成矿域。长江中下游地区燕山期以铊为代表的低温热液成矿作用和以铜(铁)金为代表的中高温热液成矿作用之间可能存在着密切的成因关系,为同一热液流体系统的产物。 相似文献
4.
贵州兴仁生物成因红铊矿及其地质意义 总被引：4，自引：0，他引：4
贵州兴仁滥木厂铊矿床中主要工业矿物红铊矿(lorandite )是在沉积成岩时由生物富集形成的铊矿物,在铊矿石中可见到大量的微古动物化石,其中有孔虫和苔藓虫类占绝大部分。绝大部分微古动物化石都被含铊矿液交代,形成保留生物假像的红铊矿物斜硫砷汞铊矿。生物成因红铊矿的发现为矿床成矿模式和成矿时代的厘定提供新的证据。生物富集成矿和热液改造成矿是该矿床最主要的成矿特征。对生物群时限,硫同位素组成和生物富集成矿现象分析表明,生物富集成矿阶段发生在晚二叠世,即海西晚期,而热液改造成矿阶段则发 生在中三叠世,即印支早期。在热液改造成矿阶段形成的矿石中见不到生物假像铊矿物,其完全被典型热液铊矿物所替代。 相似文献
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南华砷铊矿床元素地球化学和成矿模式 总被引：29，自引：3，他引：26
南华砷铊矿床位于云南省南华县城东南,北距县城５５ｋｍ。矿床产于上侏罗统江边组雄黄厂段（Ｊ３＾１ｃ）,以砷和铊元素组合为特征,属于典型的低温热液改造矿床。通过矿床地质、稀土元素和成矿模式的研究,对矿床成矿作用进行讨论。卤素,尤其氯是铊富集成矿的矿化剂,铊价态变化在富集成矿过程中具有重要作用。成矿流体是具有Ｃｅ和Ｅｕ负异常的酸性溶液,基本保留了矿源层的稀土分布模式。在成矿过程中亲石元素和亲硫元素均不同 相似文献
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凭祥地区金矿床受断层构造与酸性火山岩的双重控制。围岩蚀变为黄铁矿化、绢云母化、硅化等。矿床的形成经历了两个成矿期：热液成矿期与表生氧化期。热液成矿期金由热液迁移至围岩，被黄铁矿与毒砂吸附。表生氧化期黄铁矿与毒砂氧化形成氧化铁矿物，金被吸附到氧化铁矿物之上得到富集。对矿化岩石与围岩的微量元素与稀土元素分析结果表明，本区金矿以Au-As-Sb-Hg组合为特征，As是金的找矿指示元素。根据金矿床的矿物组合与微量元素特征以及矿床地质条件推测，本区金矿床属低温热液矿床，形成时代为燕山期。 相似文献
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云南维西大宝山铜多金属矿床位于青藏高原东南缘哀牢山-金沙江构造带之“三江”成矿带中,为一处典型受构造控制的浅成热液矿床。矿床内不同矿段具有不同的矿石组合类型,相同矿段不同埋深亦具有不同的矿石组合类型。其中望香台矿段由深至浅主要为辉铜矿、白云石(铁白云石)组合,辉铜矿(铜蓝)、孔雀石、白云石组合及孔雀石、蓝铜矿、辉铜矿、褐铁矿、石英组合;滑石板矿段由深至浅主要为黄铜矿、黄铁矿、石英组合,辉铜矿、白云石(铁白云石)组合类型。依据矿石组合类型将矿床成矿期划分为岩浆期、浅成低温热液成矿期及表生期三个成矿期和黄铁矿阶段、黄铜矿阶段、辉铜矿阶段、硫化矿混合阶段及氧化矿阶段五个成矿阶段。综合分析认为,矿体形成于含矿岩浆热液沿构造裂隙上移过程中,随着外部环境变化及外来物质的参与,富含铜、银等元素的成矿流体在有利部位富集成矿,且后期发生了强烈的次生富集及氧化还原作用。 相似文献
8.
扬子板块周缘MVT型铅锌矿床闪锌矿微量元素组成特征与指示意义:LA-ICPMS研究 总被引：3，自引：1，他引：2
扬子板块周缘铅锌多金属成矿带内分布着数以百计的沉积岩容矿型铅锌矿床,它们不仅是我国主要的铅锌矿产地,同时也是重要的稀散元素(Ge、Ga等)生产基地。本次研究采用LA-ICPMS技术分别测定了扬子板块西南缘的会泽铅锌矿床、金沙厂铅锌矿床、大梁子铅锌矿床,扬子板块北缘的马元铅锌矿床以及扬子板块东南缘的凤凰茶田锌(铅)汞矿床中闪锌矿的微量元素组成,以揭示闪锌矿中微量元素(稀散元素)的富集规律和赋存状态,并为矿床成因类型的厘定及稀散元素矿产资源综合利用提供更多依据。LA-ICPMS微量元素测定结果显示闪锌矿中不同微量元素(稀散元素)分布不均匀,但这些矿床中闪锌矿总体以富集稀散元素Ge、Ga、Cd,贫In、Se、Tl、Te为特征,其Fe、Mn含量要明显低于与岩浆热液有关的高温闪锌矿,指示了扬子板块周缘铅锌矿床可能形成于中-低温成矿流体,而与岩浆热液无直接的成因联系,此外这些矿床中闪锌矿富Ge贫In的特征与其他的密西西比河谷型铅锌矿床(MVT)一致。同时,本次研究综合分析了闪锌矿中不同微量元素(稀散元素)之间的相关关系,并与闪锌矿微量元素LA-ICPMS时间分辨率特征相结合,研究表明:这些铅锌矿床中稀散元素Ge可能主要通过3Zn2+?Ge4++2(Cu+,Ag+)和2Zn2+?Ge4++□(晶体空位)的替代方式进入闪锌矿,Ga在闪锌矿中富集机理主要为2Zn2+?(Cu,Ag)++(Ga,As,Sb)3+。此外,为进一步揭示不同成因类型铅锌矿床中稀散元素的富集规律,本文还系统对比了全球范围内不同类型铅锌矿床闪锌矿的稀散元素(均为LA-ICPMS数据)组成特征,并初步探讨了造成不同成因闪锌矿中稀散元素(Ge、Ga和In)差异性富集的主要控制因素,研究表明:(1) Ge在中低温盆地卤水成矿系统(MVT和SEDEX矿床)和岩浆-火山热液成矿系统(浅成脉状铅锌矿床和VMS矿床)形成的闪锌矿中均可能富集成矿,但中低温浅成脉状矿床中Ge的富集程度要明显高于高温脉状矿床,指示了成矿温度是控制闪锌矿中Ge富集的一个重要因素。(2)铅锌矿床闪锌矿中In主要为岩浆来源,In倾向于在成矿温度较高的岩浆及火山热液成因铅锌矿床中富集成矿,而壳源的MVT和SEDEX型铅锌矿床中闪锌矿均贫In。可见除形成温度外,成矿物质来源是决定闪锌矿是否富In的关键因素。(3)除矽卡岩型铅锌矿床外,其他不同成因类型、不同形成温度的铅锌矿床中闪锌矿均可能富Ga。矽卡岩型铅锌矿床闪锌矿具有明显的贫Ga、Ge的特征,这可能是由于矽卡岩化过程中稀散元素Ga、Ge大量进入早期矽卡岩矿物,进而导致了成矿流体以及随后形成的闪锌矿中Ga、Ge的贫化。综上所述,闪锌矿中稀散元素富集与否和富集程度受成矿物质来源、成矿流体性质以及流体演化过程等多因素的综合控制。(4)扬子板块周缘铅锌矿床闪锌矿的微量元素(稀散元素)组成特征指示了它们形成于中低温成矿环境,稀散元素的富集规律与其它MVT型铅锌矿床类似。 相似文献
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蒙西斑岩铜钼矿床成矿阶段及成矿元素统计分析意义 总被引：2，自引：0，他引：2
蒙西斑岩铜钼矿位于东准噶尔北塔山-纸房-琼河坝岛弧带东段琼河坝地区,属形成于断裂背景下的斑岩型矿床.脉状矿化是该矿床主要矿化类型,不同脉体有一定生成顺序.早期钾化阶段形成磁铁矿钾长石石英脉、硫化物钾长石石英脉、及高温阶段磁铁矿碳酸盐脉.进入硅化作用阶段后,形成磁铁矿石英脉、辉钼矿石英脉、黄铜矿黄铁矿石英脉、黄铁矿石英脉及少硫化物石英脉.成矿作用后期形成不含或少含硫化物的石英脉、碳酸盐脉.结合矿化蚀变带内地化元素的聚类分析、因子分析特征,初步将蒙西铜钼矿成矿作用分为早期构造挤压作用成矿期和岩浆热液作用成矿期.岩浆热液成矿期是该矿床的主要成矿时期,可细分为高温成矿阶段和中低温成矿阶段,分别对应形成Mo,Cu的富集矿化. 相似文献
10.
新疆哈密卡拉塔格块状硫化物矿床金银赋存状态研究 总被引：3，自引：0，他引：3
新疆哈密红海黄土坡VMS矿床位于东天山卡拉塔格隆起带,是卡拉塔格矿集区内新发现的块状硫化物矿床。矿体产于卡拉塔格隆起带核部火山沉积岩建造中,具有典型的VMS型矿床“上层下脉”二元结构特征。该矿床中含金硫化物矿石主要有块状黄铁矿黄铜矿、块状黄铁矿黄铜矿闪锌矿、块状黄铁矿闪锌矿黄铜矿和块状闪锌矿。文中在对各类含金硫化物矿石进行详细的矿相学研究基础上,结合扫描电子显微镜与能谱仪联用技术(SEM/EDS),对硫化物样品中金、银的赋存状态进行研究。结果表明,4种块状硫化物中的主要矿物形成于多个期次,主要包括VMS成矿期(黄铁矿阶段、闪锌矿黄铜矿黝铜矿方铅矿阶段、石英重晶石阶段)、热液叠加期(石英黄铁矿黄铜矿闪锌矿方铅矿阶段)和表生期(铜蓝纤铁矿阶段)。矿区首次发现4颗金银金属互化物(银金矿、碲银矿),其较大的化学成分差异指示了热液环境由中酸性中性转变为更有利于Au、Ag迁移沉淀的偏碱性。后期的偏碱性热液对VMS成矿期形成矿物产生了交代作用,使得Au、Ag活化再富集。由于后期热液叠加改造,红海VMS型矿床中Au、Ag不仅赋存于VMS成矿期后期中低温闪锌矿黄铜矿阶段,也赋存于VMS成矿期早期中高温黄铁矿阶段,并贯穿整个热液叠加期。各含金矿物组合中除4颗金银金属互化物外Au多呈显微不可见状态,推测Au、Ag主要以原子或离子形式赋存于矿物晶格中或矿物空位处。 相似文献
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Guboglo M. N. 《GeoJournal》1980,4(1):53-58
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen. 相似文献
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Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers 《《幕》》2008,31(3):315-318
The Global Stratotype Section and Point （GSSP） for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP. As a result, in 2000, the Subcommission on Silurian Stratigraphy （SSS） proposed undertaking a formal restu@ of this GSSP, which was subsequently approved by the International Commission of Stratigraphy （ICS）. The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob＇s Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the bios- tratigraphical definition of the boundary should be revised. The previously defined, basal Silurian grapto- lite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher E acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological Sciences. This is the first GSSP to undergo formal restudy and redefini- tion, and the proposal also included a recommended procedure for restudy of GSSPs. 相似文献
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Deviation of the major axis of the inertia ellipsoid of the Moon from the direction toward the Earth
B. P. Kondratyev 《Astronomy Reports》2017,61(8):709-714
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″. 相似文献
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东濮凹陷北部沙三中亚段广泛发育盐岩和烃源岩,这两个看似不能共存的物质却在这里互层共生。该时期研究区沉积特征为多盐韵律与多层烃源岩互层共生、连续沉积,单个盐韵律厚度从几米到十几米,烃源岩有机质丰度高、类型好。平面上,两者在湖盆沉积沉降中心共生;垂向上,高有机质丰度、好干酪根类型与高盐度地层具有较好的对应关系。因而成为恢复古气候和古环境的重要研究对象。通过岩石学、古生物学以及Sr/Ba、B/Ga、(V+Ni+Mn)、Fe/Mn、Sr/Cu、Mg/Ca、V/(V+Ni)、稀土元素含量和氯同位素等方法对凹陷北部沙三中亚段的沉积环境进行研究。结果表明,凹陷北部沙三中亚段为深水沉积的还原环境,古盐度较高,达到半咸水-咸水沉积;微量元素和孢粉化石特征表明研究区沙三中亚段为温暖潮湿的环境。 相似文献
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Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base. 相似文献
18.
Fouad N. Ibrahim Dr. 《GeoJournal》1988,17(1):133-141
Taking the example of W Sudan, an analysis of the climatic incidents leading to the two recent famine disasters is made. On this natural background, the human side is investigated. Focus is directed towards the fragile economic structure of the famine-prone population groups. An early-warning system for famine in the Sahelian Zone is proposed taking grain production and storage, livestock development and the relationship between the prices of livestock and grain as major indicators. 相似文献
19.
郯庐断裂南段研究进展与断裂性质讨论 总被引：13，自引：3，他引：13
据1：5万区域地质调查和专题研究资料，就郯庐断裂带是否南延与消失的原因，其与大别—苏鲁造山带交截形成的假位错效应，以及与中新生代沉积盆地形成演化的关系等作了新的阐述。在此基础上，讨论了郯庐断裂带是否为巨大的左行平移断层或转换断层。认为郯庐断裂带可能是在“古郯庐带”的基础上于早侏罗世重新活动、白垩纪强烈活动的地堑型枢纽断裂带。 相似文献
20.
The Importance of the Precipitation and the Susceptibility of the Slopes for the Triggering of Landslides Along the Roads 总被引：3，自引：1，他引：2
Clemente Irigaray Francisco Lamas Rachid El Hamdouni Tomás Fernández José Chacón 《Natural Hazards》2000,21(1):65-81
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning. 相似文献