龙首山铀成矿带成矿规律与成矿模式     

施文静  胡俊祯 《铀矿地质》1993,(3)

龙首山成矿带查明有两个重要的铀成矿系列:与中条期混合岩化、岩浆作用有关的多阶段、多来源、复成因铀成矿系列,及与加里东晚期花岗岩浆演化有关的铀成矿系列。前者产出伟晶白岗岩型铀矿床,后者产出钠交代型和硅质脉型铀矿床。它们是该区地壳发展演化特定阶段的产物,成矿作用与花岗岩浆、热液演化及围岩条件关系密切,矿化在空间上受不同级别构造控制。  相似文献   

安徽省庐枞地区地球物理场分布特征与铀矿化的关系     

陈卫红 《铀矿地质》1993,(4)

庐枞地区重磁场特征,能够较好地反映区域地质背景和主要构造格架。1—4号航磁场区分别反映了沉积岩、火山岩、二长岩带和碱性正长岩带,而2—4号航磁场区又和本区3条成矿亚带相对应。中低重磁场区及其变异部位和中高辐射场梯度带是铀矿化产出的有利部位。  相似文献   

Late Cenozoic evolution of epithermal gold metallogenic provinces in Kyushu, Japan     

Yasushi Watanabe 《Mineralium Deposita》2005,40(3):307-323

Kyushu Island, Japan, is located at the junction of the Southwest Japan arc and the Ryukyu arc. There are two major late Cenozoic epithermal gold-silver provinces in Kyushu, which are termed the Northern and Southern provinces. The provinces are characterized by: 1) Pliocene volcanism dominated by calc-alkaline andesite, followed by Quaternary volcanism including extrusion of both calc-alkaline and tholeiitic magmas; 2) formation of extensional grabens; 3) Pliocene to Pleistocene mineralization, which was dominated by abundant low sulfidation (LS) epithermal deposits with a few high sulfidation (HS) examples. The two epithermal gold-silver provinces have evolved differently since about 5 Ma; the Northern province has exhibited diminished hydrothermal activity from the Pliocene to Pleistocene, whereas the Southern province has witnessed increased hydrothermal activity mainly in easterly and northerly directions. Changes of tectonic setting from the Pliocene to Pleistocene account for the variable trends in epithermal gold deposit formation. Westward oblique subduction of the Philippine Sea plate beneath the Southwest Japan arc caused development of the Hohi graben and arc-related volcanism at about 6 Ma. This was associated with widespread LS mineralization in and surrounding the Hohi graben, as is represented by the Bajo and Taio deposits. The subduction of the relatively buoyant Kyushu-Palau ridge during the early Pliocene strengthened the coupling between the slab and overriding Ryukyu arc, leading to polygenetic andesite volcanism with associated HS (Kasuga, Iwato, and Akeshi) and LS (Kushikino) mineral deposits forming in the Southern province. A change of the subduction direction of the Philippine Sea plate, from west to north-northwest in the early Pliocene, increased the orthogonal convergence rate between the Southwest Japan arc and the Philippine Sea plate, resulting in a decrease of volcanic and hydrothermal activity in the Hohi graben of the Northern province. The more northerly subduction of the Philippine Sea plate shifted the locus of the Kyushu-Palau ridge subduction northward, resulting in underplating of the older (85–60 Ma), negatively buoyant Amami basin oceanic slab in the Southern province, rather than continued subduction of the young (27–15 Ma), buoyant Shikoku basin slab. This replacement caused steepening of the slab angle and slab-rollback in the Southern province, which was associated with regional extension, an eastward shift of the Ryukyu volcanic front, and development of the Kagoshima and Shimabara grabens, as well as the Okinawa trough. Rhyolite and basalt volcanism, in addition to andesite volcanism, have occurred since 2 Ma in the area of the Ryukyu back arc; coincident LS mineralization at Hishikari and Ohkuchi was affiliated with the rhyolite volcanism. Another change of the subduction direction of the Philippine Sea plate to the northwest occurred at 2–1 Ma. The forearc sliver of the Southwest Japan arc shifted westward, in association with right-lateral strike-slip faulting along the Median tectonic line, due to the increase of the westward convergence rate. This shift resulted in shortening and cessation of graben development in the Hohi area, restricting the subsequent volcanism and related hydrothermal activity to the central part of the graben.  相似文献   

江西银山金、铜多金属矿床构造动力-火山岩浆同步一体成矿热结构模式     

刘丹英  冯志文  夏卫华  莫测辉 《矿产与地质》1998,(6)

银山金铜多金属矿床位于赣东北深断裂的北西侧。矿区大面积出露前震旦系双桥山群浅变质岩,其上有零星不整合产出的上侏罗统鹅湖岭组火山碎屑岩—熔岩。矿区褶皱构造主体为双桥山群浅变质岩构成的银山背斜,沿背斜轴部发育一条斜贯全区的剪切带。区内主要发育燕山早期的火山碎屑岩、熔岩、次火山岩及隐爆角砾岩。大量事实表明,该矿床经历了构造动力热液成矿和火山－岩浆热液成矿,两种成矿作用在时间上具同期性,在空间上两者密切相关,构成了构造动力—火山岩浆同步一体的成矿体系。  相似文献   

西秦岭降扎地区金、铀矿床年代学对比研究   总被引：9，自引：0，他引：9       下载免费PDF全文

刘家军 《地质科学》1998,33(3):300-309

西秦岭降扎地区寒武、志留系中的金、铀矿床,是我国相当重要的碳硅泥岩型矿床。根据金矿床中岩石和矿石异常铅模式年龄、氩-氩同位素年龄和钾-氩同位素年龄等,获得了一批有益的年代学信息。金矿床的各种同位素年龄数据主要有2组:(1)242-186Ma;(2)137-47Ma.结合区域地质发展史、成矿热液脉与岩脉的穿切关系以及矿床产出的其它宏观特征等,确定金矿床的成矿时代为137-47Ma,与区域铀矿床形成的主要时代(117-55Ma)相比,二者成矿时间大体相同。  相似文献   

分形理论在成矿预测中的应用   总被引：15，自引：0，他引：15  

陈春仔  金友渔 《矿产与地质》1997,11(4):272-276

分形理论是人类进行思维和探索复杂性而定量描述的一种新方法，是研究大自然界中不规则现象的有力数学工具，在地质领域中的应用非常广泛。介绍Ｒ／Ｓ分析法原则，并结合实例来研究地质体和地质现象的分形特征，确定地质异常，建立地质异常分形模型。  相似文献   

新疆准噶尔盆地北西部层间氧化带砂岩型铀矿形成条件分析   总被引：3，自引：3，他引：3  

林双幸 《铀矿地质》1997,13(2):《铀矿地质》-1997年13卷2期,13(2)-97-97,13(2)页-《铀矿地质》-1997年13卷2期,13(2)-97-97,13(2)页

本文从盆地结构、沉积盖层构造特征、盆地沉积的岩相条件及岩石地球化学地特征、区域水文地质条件以及沉积盖层中的后生改造作用等方面，分析准噶尔盆地北西部层间氧化带砂岩型铀矿形成的地质条件。  相似文献   

伊犁盆地层间氧化带砂岩型铀矿成矿模式   总被引：38，自引：7，他引：38  

陈戴生  王瑞英 《铀矿地质》1997,13(6):327-335

本文通过对５１２、５１１矿床及其它矿点的铀源、地质构造、含矿主岩岩性、古气候、层间氧化带发育条件、成矿水文地质条件等方面的研究，提出了伊犁盆地层间氧化带砂岩型铀矿的成矿模式。  相似文献   

论衡东县东岗山矿田对顶帚状构造及其控矿作用     

王甫仁 《湖南地质》1989,8(1):13-20

衡东县东岗山矿田内发育着两个完美的对顶帚状构造,它们对东岗山和吊马垄两个锡铅锌矿床的形成和富集具有极其重要的控制作用。本文介绍了它们的发育特征,讨论了形成的边界条件,进行了构造应力场分析。在此基础上,较深入地论述了它们对成矿控制的若干规律,进而具体地指出了深部找矿最有利的部位,值得验证。  相似文献   

成矿系列的结构模型研究   总被引：1，自引：0，他引：1  

翟裕生  彭润民  王建平  邓军 《高校地质学报》2003,9(4):510-519

由单个矿床研究到成矿系列和成矿系统研究，是成矿学研究的重要进展。在成矿系列理论的探索中，成矿系列的结构尤需关注，因此将成矿系列的内部结构概括为物质的、空间的和时间的三类。其中物质结构包括各矿种、矿床类型间的同源性、多样性、继承性和互补性；空间结构包括各矿种、矿床类型间的共生性、分带性、过渡性、集约性和重叠性；而成矿系列的时间结构含各矿种、矿床类型间的时限性、阶段性、渐进性和突发性，并举例论述了这些结构性质的形成条件，对深入认识成矿规律和指导找矿预测均有参考意义。  相似文献