胶东三山岛金矿床黄铁矿原位微区微量元素特征及对矿床成因的指示     

林祖苇  赵新福  熊乐  朱照先 《地球科学进展》2019,(4):399-413

胶东地区是我国最大金成矿聚集区,其金矿床的成因长期以来一直存在很大争议,三山岛金矿床是胶东地区最大的金矿床,通过采用LA-ICP-MS分析不同阶段黄铁矿中微量元素组成,可以探讨成矿流体演化及成矿物质来源。根据野外地质特征及岩相学观察,结合SEM结构分析将三山岛金矿床的黄铁矿分为3个阶段,6个亚类,即黄铁绢英岩化带(Py1)中包裹大量绢云母和石英的Py1-a和表面光滑的Py1-b,石英—黄铁矿±菱铁矿脉(Py2)中富含矿物包裹体的Py2-a和与菱铁矿共生且表面光滑的Py2-b,石英—多金属硫化物脉(Py3)中有很多细粒多金属硫化物包裹体的Py3-a和表面光滑的Py3-b。3个阶段黄铁矿晶格中金含量均很低,大部分小于1×10^-6,金主要以可见金形式存在。从早阶段到晚阶段黄铁矿中Au与Ag,Cu,Pb,Sb有较好的正相关性,且含量有逐渐增加的趋势。最早阶段黄铁矿中Co+Ni的含量很高(最高为9268×10^-6),反映了早期黄铁矿可能来源于岩浆岩源区,后期Co/Ni值逐渐降低,暗示了成矿流体温度逐渐降低。结合地质特征和黄铁矿微量元素研究,表明三山岛金矿床成矿物质可能来源于深部岩浆热液储库,通过地震泵机制沿断裂构造多次侵位成矿。  相似文献   

Geochemical Characteristics and Genetic Significance of Datangpo‐Type Manganese Ore Deposits during the Cryogenian Period     

Jiafei Xiao  Jingyang He  Haiying Yang  Chengquan Wu  Jianbin Xu  Yantao Li 《Resource Geology》2019,69(3):227-248

The Datangpo‐type manganese ore deposits, which formed during the Nanhuan (Cryogenian) period and are located in northeastern Guizhou and adjacent areas, are one of the most important manganese resources in China, showing good prospecting potential. Many middle‐to‐large deposits, and even super‐large mineral deposits, have been discovered. However, the genesis of manganese ore deposits is still controversial and remains a long‐standing source of debate; there are several viewpoints including biogenesis, hydrothermal sedimentation, gravity flows, cold‐spring carbonates, etc. Geochemical data from several manganese ore deposits show that there are positive correlations between Al₂O₃ and TiO₂, SiO₂, K₂O, and Na₂O, and strong negative correlations between Al₂O₃ and CaO, MgO, and MnO in black shales and manganese ores. U, Mo, and V show distinct enrichment in black shales and inconspicuous enrichment in Mn ores. Ba and Rb show strong positive correlations with K₂O in manganese ores. Cu, Ni, and Zn show clear correlations with total iron in both manganese ores and black shales. ∑REE of manganese ores has a large range with evident positive Ce anomalies and positive Eu anomalies. The Post Archean Australian Shale (PAAS) normalized rare earth element (REE) distribution patterns of manganese ores present pronounced middle rare earth element (MREE) enrichment, producing “hat‐shaped” REE plots. ∑REE of black shales is more variable compared with PAAS, and the PAAS‐normalized REE distribution patterns appear as “flat‐shaped” REE plots, lacking evident anomaly characteristics. δ¹³C values of carbonate in both manganese ores and the black shales show observable negative excursions. The comprehensive analysis suggests that the black shales formed in a reducing and quiet water column, while the manganese ores formed in oxic muddy seawater, which resulted from periodic transgressions. There was an oxidation–reduction cycle of manganese between the top water body and the bottom water body caused by the transgressions during the early Datangpo, which resulted in the dissolution of manganese. Through the exchange of the euphotic zone water and the bottom water, and episodic inflow of oxygenated water, the manganese in the bottom water was oxidized to Mn‐oxyhydroxides and rapidly buried along with algae. In the early diagenetic stage, Mn‐oxyhydroxides were reduced and dissolved in the anoxic pore water and then transformed into Mn‐carbonates by reacting with HCO₃^? from the degradation of organic matter or from seawater. In the intervals between transgressions, continuous supplies of terrigenous clastics and the high productive rates of organic matter in the euphotic zone resulted in the deposition of the black shales enriched in organic matter.  相似文献   

Geochronology and mineralogy of the Weishan carbonatite in Shandong province,eastern China     

《地学前缘(英文版)》2019,10(2):769-785

The Weishan REE deposit is located at the eastern part of North China Craton (NCC), western Shandong Province. The REE-bearing carbonatite occur as veins associated with aegirine syenite. LA-ICP-MS bastnaesite Th-Pb ages (129 Ma) of the Weishan carbonatite show that the carbonatite formed contemporary with the aegirine syenite. Based on the petrographic and geochemical characteristics of calcite, the REE-bearing carbonatite mainly consists of Generation-1 igneous calcite (G-1 calcite) with a small amount of Generation-2 hydrothermal calcite (G-2 calcite). Furthermore, the Weishan apatite is characterized by high Sr, LREE and low Y contents, and the carbonatite is rich in Sr, Ba and LREE contents. The δ¹³C_V-PDB (−6.5‰ to −7.9‰) and δ¹³O_V-SMOW (8.48‰–9.67‰) values are similar to those of primary, mantle-derived carbonatites. The above research supports that the carbonatite of the Weishan REE deposit is igneous carbonatite. Besides, the high Sr/Y, Th/U, Sr and Ba of the apatite indicate that the magma source of the Weishan REE deposit was enriched lithospheric mantle, which have suffered the fluid metasomatism. Taken together with the Mesozoic tectono-magmatic activities, the NW and NWW subduction of Izanagi plate along with lithosphere delamination and thinning of the North China plate support the formation of the Weishan REE deposit. Accordingly, the mineralization model of the Weishan REE deposit was concluded: The spatial-temporal relationships coupled with rare and trace element characteristics for both carbonatite and syenite suggest that the carbonatite melt was separated from the CO₂-rich silicate melt by liquid immiscibility. The G-1 calcites were crystallized from the carbonatite melt, which made the residual melt rich in rare earth elements. Due to the common origin of G-1 and G-2 calcites, the REE-rich magmatic hydrothermal was subsequently separated from the melt. After that, large numbers of rare earth minerals were produced from the magmatic hydrothermal stage.  相似文献   

湘南地区“黄沙坪式”铅锌矿床地质特征及找矿方向   总被引：9，自引：0，他引：9  

黄革非 《湖南地质》1999,(Z1)

“黄沙坪式”铅锌矿是实现湘南地区新一轮铅锌找矿重大突破的主攻类型。本文系统介绍了这类矿床的地质特征和成矿规律,指出了主要找矿标志和优选靶区,并提出了下步工作建议  相似文献   

八庙-青山金红石矿床地球化学特征   总被引：6，自引：0，他引：6  

徐少康 《矿产与地质》1999,13(5):293-298

金红石矿床含矿岩石常量元素总体上与玄武岩接近,但以低硅,高钛,高ＣＯ２,高碱度为特征。矿床微量元素与地壳的差别显著,稀土元素较高,分布模式呈轻稀土富集型,Ｅｕ一般为正常型与碧玄岩最接近,Ｔｉ与Ｂａ,Ｃｏ,Ｐｂ,Ｓｒ,Ｔｈ,Ｖ,Ｙ及稀土元素呈正相关与Ｃｒ和Ｎｉ呈负相关,δ＾３４Ｓ多数与（超）铁镁质岩石接近,最大值小于且靠近现代海水。  相似文献   

江西银山铜多金属矿床成因再认识   总被引：5，自引：0，他引：5  

黄定堂 《矿产与地质》1999,13(4):199-203

从矿体形态、蚀变、矿化分带、稳定同位素和矿物包裹体等方面论述了矿床与本区岩浆活动在时间、空间和成矿物质来源等方面的关系,提出了银山铜多金属矿床是与燕山早期岩浆活动有关的火山—次火山热液矿床的新认识。  相似文献   

大水沟碲矿床成矿物理化学条件研究   总被引：11，自引：0，他引：11       下载免费PDF全文

李保华  曹志敏 《地质科学》1999,34(4):463-472

本文在对大水沟碲矿床各成矿阶段矿物共生分析、成矿温度、矿液成分研究的基础上,对成矿的其它物理化学条件,如pH、f_O2、f_S2、f_Te2等作了热力学计算,并结合矿床地质资料,计算与分析了成矿过程中碲的迁移形式及富集机理。  相似文献   

乌拉嘎金矿床地质地球化学特征研究   总被引：8，自引：3，他引：5  

王永祥  吴国学  白士俊  韩洪伟  吕志刚  汪振涌 《世界地质》2005,24(4):338-343

乌拉嘎金矿矿体赋存于燕山晚期的斜长花岗斑岩与黑龙江群下亚群接触带附近的近东西向展布的构造角砾岩中,围岩蚀变强烈;金矿化主要受角砾岩带控制。矿床成矿微量元素组合为Au、Hg、As、Sb,且含量均呈向下递增的趋势。LaN／YbN值变化范围为14．146～28．311,稀土元素配分模式为右倾的轻稀土富集型;∑LREE：165．76～62．68;∑HREE：45．82～15．2;LREE／HREE为6．09～4．124,为轻稀土富集型。岩体中流体包裹体以低盐、低压且有天水加入为特征,为典型的浅成低温热液型矿床。  相似文献   

新疆哈密卡拉塔格铜(锌)矿红石幅1∶50 000矿产地质图数据库          下载免费PDF全文

王丰丰  邓小华  李德东  卫晓锋  吕晓强  王燕超  李永胜 《中国地质》2020,47(S2):185-195

新疆哈密卡拉塔格铜(锌)矿红石幅(K46E009008)1∶50 000矿产地质图数据库是根据《固体矿产地质调查技术要求(1∶50 000)》(DD2019-02)和行业其他标准及要求,在充分利用1∶200 000、1∶50 000等区域地质调查工作成果资料的基础上,采用数字填图系统进行野外地质专项填图,并应用室内与室外填编图相结合的方法完成。本数据库将中-上奥陶统荒草坡群大柳沟组、下志留统红柳峡组和卡拉塔格组的建造类型进行了重新划分,把图幅内侵入岩时代划分为志留纪、泥盆纪、二叠纪等3期,建立了岩浆岩演化序列。图幅区内有大中小型矿床和矿点共8个,成矿时代集中分布在志留纪、石炭纪,赋矿围岩为火山碎屑岩和次火山岩,该区优势矿产以铜锌金为主,矿床类型以VMS型和次火山热液脉型矿床为主,分布在图幅东南一带。除金属矿产外,尚有膨润土矿床产出,具有较好的找矿潜力。本数据库包含5个地层单位和3期岩浆岩资料,数据量约为 15.1 MB。这些数据充分反映了该图幅 1∶50 000 矿产地质调查示范性成果,对该区矿产资源研究和勘查等具有参考意义。  相似文献   

云南广南县老寨湾金矿地质特征及找矿标志     

高李阳  顾雄  吴小梅 《云南地质》2020,(1):71-75

广南县老寨湾金矿位于滇、黔、桂“金三角”重要成矿区带上,金矿体矿体呈似层状赋存于断层构造破碎带或层间构造破碎带中,构造控矿明显。矿体围岩均为下泥盆统坡松冲组第一段(D1ps1)硅化石英砂岩;矿床成因属中-低温热液叠加改造型金矿床,断层构造、硅化等矿化蚀变及地球化学异常是重要的找矿标志。  相似文献