湘南宝山铅锌多金属矿区花岗闪长斑岩及其暗色包体成因：锆石U-Pb年代学、岩石地球化学和Sr-Nd-Hf同位素制约   总被引：8，自引：4，他引：4  

谢银财  陆建军  马东升  章荣清  高剑峰  姚远 《岩石学报》2013,29(12):4186-4214

本文对湘南宝山铅锌多金属矿区花岗闪长斑岩及其暗色包体进行了系统的锆石U-Pb年代学、岩石地球化学和Sr-Nd-Hf同位素研究,探讨其岩石成因和构造意义。LA-ICP-MS锆石U-Pb定年表明,宝山花岗闪长斑岩成岩年龄为156~158Ma,暗色包体的形成年龄为155.2±1.4Ma,与寄主岩的成岩年龄一致。宝山花岗闪长斑岩为准铝质花岗岩,富集K、Rb、U等大离子亲石元素,亏损Nb、Ti、P等元素,Nb/Ta平均比值为11.3,（⁸⁷Sr/⁸⁶Sr）_i值为0.7095~0.7115,ε_Nd（t）值为-7.3~-5.0,t_2DM（Nd）值为1.35~1.54Ga,锆石ε_Hf（t）值为-14.0~-9.0。暗色包体呈细粒结构,具浑圆的外形,与寄主花岗闪长斑岩接触界线清晰,具暗色的冷凝边,常见针状磷灰石。暗色包体具较低的SiO₂含量（55.46%~57.30%）,较高的K₂O含量（5.86%~6.90%）,富集Rb、Ba、Th、U等大离子亲石元素,亏损Nb、Ta、Ti等元素,Nb/Ta平均比值为15.3,（⁸⁷Sr/⁸⁶Sr）_i值为0.7062~0.7063,ε_Nd（t）值为-2.1~-1.9,锆石ε_Hf（t）值为-12.1~-4.7。与寄主花岗闪长斑岩相比,暗色包体含有较高的Fe、Mg、V、Cr等相容元素。主微量元素和同位素特征表明,宝山花岗闪长斑岩是由来自经俯冲沉积物熔体交代过的富集岩石圈地幔且富水富钾的底侵基性岩浆与由其引起的下地壳部分熔融形成的长英质岩浆发生混合形成,暗色包体则是来自该底侵基性岩浆与少量长英质岩浆发生混合形成。Sr-Nd同位素模拟表明,宝山花岗闪长质岩浆由大约20%~30%的富集地幔物质和70%~80%的地壳物质组成。892±20Ma继承锆石核的ε_Hf（t）值为+6.0,t_DM（Hf）年龄为1.21Ga,与江南造山带东段新元古代岛弧岩浆的Hf同位素特征一致,推断在花岗闪长斑岩的源岩部分熔融过程中有新元古代岛弧岩浆岩物质的加入,新元古代岛弧岩浆带及扬子与华夏陆块弧陆碰撞带从萍乡向南延伸部分可能与郴州-临武断裂相接。在燕山早期（190~150Ma）,受古太平洋板块俯冲作用影响,南岭地区处于岩石圈伸展-减薄的构造环境,由于地幔玄武质岩浆底侵至古老地壳源区,诱发地壳发生部分熔融作用,伴随着壳幔岩浆混合作用,形成了该区众多花岗质岩石。  相似文献   

滇西北地区斑岩含矿性评价的常量元素标志探讨     

刘洪滔  张兴林  颜自给 《矿产与地质》2013,(1):76-82

文章介绍了滇西北地区斑(玢)岩分布情况、主要斑(玢)岩体的岩石化学特征,并利用常量元素标志对岩体的铜金含矿性进行评价,认为滇西北地区的斑(玢)岩体可分为五个岩带,金矿成矿有利岩体和铜矿成矿有利岩体两大类型,指出滇西地区具有广阔的斑岩找矿前景。  相似文献   

地质统计学及其在云南金宝山铂钯矿的应用   总被引：2，自引：0，他引：2  

刘方成  秦德先  燕永锋  李保珠  秦来勇  洪托 《地质与资源》2005,14(4):293-296

应用地质统计学的理论和方法,编制了矿床数学-经济模型软件包,并使用该软件建立了金宝山铂钯矿矿床数学经济模型,计算了矿石储量,为提高矿山生产的经济效益、充分合理利用矿产资源提供了科学依据.  相似文献   

新疆巴音铜矿床硫同位素地球化学研究     

徐文炘  李蘅  邓贵安  庞春勇 《中国岩溶》2004,23(4):339-343

采用硫同位素方法,对新疆巴音铜矿床硫化物和硫酸盐矿物进行硫同位素测定,获得硫化物和硫酸盐的δ34 S值在- 17. 5‰～ + 10. 0‰ ,硫同位素富集顺序为δ34 S重晶石> δ34 S黄铁矿> δ34 S辉铜矿> δ34 S黄铜矿。对矿床矿物包裹体测定及矿物稳定场进行物理化学计算,获得成矿温度约250℃ , log f O2为- 34. 37～- 38. 42;log f s2 为- 8. 59～-14. 0; log f CO2为-2. 3; pH值为3～6。对矿床δ34 S?S计算,获得δ34 S?S为+ 10‰ ,指示出矿石硫源来自岩浆与海水硫酸盐混合。   相似文献   

石英脉型钨多金属矿床的扇状成矿实例及找矿模型     

方贵聪  王登红  黄长帅  杨富强  许以明  冯佐海  李学彪  曾强  严长华 《矿床地质》2024,43(3):613-628

石英脉型钨矿床是中国数量最多的钨矿床类型,但保有储量消耗迅速,迫切需要创新找矿模型,指导找矿突破。文章结合二十余年的找矿实践,通过详细分析扇状成矿矿床实例,构建了石英脉型钨矿床新的找矿模型。该模型强调赋矿裂隙为岩浆动力成因,在花岗岩体顶部呈扇状分布型式,岩浆期后热液恰在裂隙张开时充填其中而形成扇状成矿系统;提出“就岩找矿”、“就矿找矿”、“就矿找岩”的地质、地球化学和地球物理标志,指导矿床尺度的勘查工程部署。截至目前,该模型已在广东禾尚田钨锡矿床、广西珊瑚钨锡矿床、广西社垌钨钼矿床、江西盘古山钨铋矿床等获得了验证,找矿成效显著。  相似文献   

Discovery of eclogite in the Bangong Co–Nujiang ophiolitic mélange,central Tibet,and tectonic implications     

《Gondwana Research》2016

An eclogite has been recently identified within ophiolitic mélange in the western segment of the Bangong Co–Nujiang suture zone, at Shemalagou in the Gaize area of central Tibet. The eclogite consists of garnet, omphacite, phengite, rutile, quartz, diopside, and amphibole. The omphacite, which has not been recognized in the suture zone until this study, occurs as rare relics within diopside grains in the eclogite. Phase equilibria modeling shows that the eclogite formed under P–T conditions of 22–28 kbar and 600–650 °C with a low geothermal gradient of ca. 8 °C/km, suggesting that it formed during the subduction of oceanic crust. The protoliths of the eclogite and coexisting garnet amphibolites have geochemical characteristics similar to those of normal mid-ocean ridge basalt (N-MORB), confirming that the eclogites formed from oceanic crust. The presence of high-pressure (HP) eclogite indicates that the ophiolitic mélange in the Bangong Co–Nujiang suture zone underwent oceanic subduction and was subsequently exhumed. We conclude that this ophiolitic belt represents a newly identified HP metamorphic belt in the Tibetan Plateau, adding to the previously recognized Songduo and Longmucuo–Shuanghu eclogite belts. This discovery will result in an improved understanding of the tectonic evolution of the Bangong Co–Nujiang suture zone and the Tibetan Plateau as a whole.  相似文献   

Early Mesozoic magmatism and tectonic evolution of the Qinling Orogen: Implications for oblique continental collision     

《Gondwana Research》2020

The Qinling Orogenic Belt in Central China is formed by an oblique continental collision between the North China and South China Blocks. In this review, we summarize the knowledge of the early Mesozoic magmatism, in combination with the coeval metamorphic characteristics, regional structural features and depositional history in the foreland and hinterland basins along the Qinling-Dabie Orogen. The early Mesozoic tectonic evolution of the Qinling is divided into four stages. Stage I (~250–235 Ma) is characterized by medium-K calc-alkaline magmatism in the western Qinling induced by slab roll-back. Meanwhile, ultrahigh-pressure metamorphism was triggered by continental subduction in the Sulu-Dabie, indicating a diachronous closure of the ocean. Stage II (~235–225 Ma) is recognized as a magmatic gap. Depositional variations of sedimentary facies and compressional deformations with an increased crustal thickness reflect the initial collision in the Qinling. Stage III (~225–210 Ma) is distinguished by a magmatic flare-up event. Abundant mantle-derived melts coupled with extensive crustal-derived melts were coeval with rapid uplift, strike-slip movement and regional crustal thickening in the Qinling as well as retrograde metamorphism in the Sulu-Dabie. The main tectonic driver was the propagating detachment of the subducted oceanic slab at gradually shallower depth from the Sulu-Dabie to the Qinling. Stage IV (~210–190 Ma) magmatism is dominated by high silica granites derived from metasedimentary rocks. The rapid denudation rates and extensional structures indicate gravitational collapse and regional delamination of the thickened crust. In addition to the strike-slip faults and block extrusion, the Qinling is characterized by asymmetric distribution patterns of magmatism and metamorphism, different melting mechanisms over time; diachronous depositions, differential uplift and non-uniform crustal thickening, and regional delamination of the thickened orogenic root. All these features are the result of the oblique collision, which is a common process in nature, and therefore could be applied to other orogens.  相似文献   

菌藻对碳酸盐颗粒的泥晶化作用研究─以滇西保山地区下石炭统研究为例   总被引：4，自引：0，他引：4  

韦龙明 《沉积学报》1995,13(3):89-97

碳酸盐颗粒泥晶化由真菌类和藻类的穿孔所引起，颗粒泥晶化可划分为四个阶段６种类型，泥晶套和泥晶铸型分别代表泥晶化的成长、成熟阶段。丰富的泥晶化颗粒为浅滩标志；泥晶化的深度与沉积速度成反比；泥晶化均匀程度与颗粒翻转次数成正比；颗粒泥晶化类型组合与风暴沉积有关；暴露环境出现溶蚀孔洞或负鲕。菌藻的泥晶化作用可加速海水及成岩压实作用对颗粒的破碎和细化并产生内碎屑和灰泥；鲕粒泥晶化后转变为辐射鲕和假鲕。  相似文献   

广西龙胜地区金矿地质特征及找矿方向     

黄杰  莫江平 《矿产与地质》2003,17(1):20-23

广西龙胜地区金矿属于脆-韧性剪切绿岩型,成矿物源主要为上元古界地层中的初始富集金,在“面状”渗秀性构造带的地质环境中,多次强烈的构造活动驱使地下热（卤）水、区域变质水等热水溶液渗秀、循环而形成成矿溶液,在构造动力作用下沿断裂、裂隙运移,在适宜构造场沉淀富集成矿。金矿化类型有石英脉型和构造蚀变岩型两类,前者分为细网脉型、脉带型、碎型石英脉型;后者分为细碎屑岩质构造蚀变岩型、碳硅质构造蚀型、基性-超基性岩质构造蚀变岩型。该区具有良好的找矿前景,提出了以构造活动强烈、构造形迹明显的较低级次的脆-韧性剪切断裂、裂隙带和浅变质泥质（粉砂）岩、浅变质含硅含碳泥质（粉砂）岩组合找矿的思路,并重视进行构造蚀变岩型金矿的找矿。  相似文献   

遥感与化探数据融合处理技术方法及应用研究   总被引：5，自引：2，他引：5  

吴德文  袁继明  张远飞  朱谷昌 《国土资源遥感》2005,16(3):44-47

遥感找矿信息与化探异常之间存在套合和藕合两种空间关系，通过数据融合处理，可以对其相关性作出正确的识别和判断，以达到综合找矿的目的。基于此，笔者以东天山地区作为试验区，进行了遥感与化探数据融合处理的技术方法研究及试验应用。  相似文献