东昆仑古特提斯造山过程与金成矿作用

发布时间：2018-03-04 19:40

  本文选题：东昆仑造山带　切入点：古特提斯　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：东昆仑古特提斯造山带独特的大地构造位置、复杂的构造环境、频繁的岩浆活动及不同程度的变质作用,不但清晰地记录了区域构造-岩浆-成矿作用的造山旋回过程,而且造就了该带多样的金属矿化类型和丰富的矿产资源,成为研究造山过程中金属超量富集的理想场所,也是揭示壳幔物质交换与成矿耦合机制的窗口。本文通过野外地质调研、同位素定年和地球化学分析,再造了东昆仑古特提斯造山带构造-岩浆-成矿的演化过程,揭示了重大构造事件与大规模成矿的耦合关系,构建了金成矿的深部动力学机制,破解了东昆仑古特提斯造山带金成矿之谜。研究认为,东昆仑古特提斯造山带经历了从板片俯冲(278～240 Ma)到陆-陆碰撞(240～228 Ma)及后碰撞伸展(228～210 Ma)等完整的造山演化过程;相伴发生了～240 Ma同碰撞期中酸性岩浆活动、～228 Ma后碰撞镁铁质岩浆活动等重大构造-岩浆事件;与构造-岩浆活动相对应,发生了 2次大规模成矿事件(～240 Ma、～228 Ma),形成以大场、五龙沟、坑得弄舍、沟里、托克妥等为代表的一系列重要的矿床。其中,巴颜喀拉的大场金矿床为类卡林型金矿,是后碰撞伸展阶段成矿作用的产物;昆南的坑得弄舍金铅锌矿床是喷流沉积叠加改造成矿作用的产物;昆中的五龙沟金矿床是多期次成矿叠加的产物,造山型金矿集中于220～237 Ma,金主成矿期与区内的韧性剪切带和脆性断裂的活动时代相吻合,矽卡岩型矿化主要发生在～240Ma;昆中的托克妥斑岩型铜金(钼)矿床是板块俯冲阶段的典型产物,形成于232 Ma,是板块俯冲流体交代的产物。昆北的斑岩-矽卡岩型多金属矿床成矿作用连续,以中-晚三叠世为主。可以看出,东昆仑古特提斯成矿带不但具有密集成带、分布集中,多种类型和多期次叠加成矿的特点,而且大规模成矿事件与造山过程中同碰撞和后碰撞构造体制转换期相吻合,而岩浆底侵和壳幔岩浆的混合是造山带成矿作用的驱动机制。
[Abstract]:The unique tectonic location, complex tectonic environment, frequent magmatic activity and varying degrees of metamorphism in the Paleottes orogenic belt of East Kunlun not only clearly record the orogenic cycle of regional tectonic-magmatic mineralization, Moreover, it has brought up various types of metal mineralization and abundant mineral resources, and has become an ideal place to study the enrichment of metals in the orogenic process. It is also a window to reveal the coupling mechanism of material exchange and mineralization between crust and mantle. Through field geological investigation, isotopic dating and geochemical analysis, the evolution of tectonic-magma metallogenic process in the PaleoTethys orogenic belt of East Kunlun has been reconstructed. The coupling relationship between major tectonic events and large-scale mineralization is revealed, the deep dynamic mechanism of gold mineralization is constructed, and the mystery of gold mineralization in the ancient Tethys orogenic belt of East Kunlun is solved. The East Kunlun PaleoTethys orogenic belt has undergone a complete orogenic evolution from plate subduction to land- land collision (240 Ma) and post-collision extension (2285210Ma). It was accompanied by two major tectonic-magmatic events, such as tectonic-magmatic events, which occurred after the collision of 228Ma, and 2 large-scale metallogenic events, such as 240 Ma-228MaA, which were formed in a large field, and were associated with tectonic-magmatic activities and other major tectonic-magmatic events. The major tectonic-magmatic events occurred at 228Ma, corresponding to tectonic-magmatic activities. A series of important deposits represented by Wulonggou, Kendronsher, Gouli and Toktor. Among them, the Dachang gold deposit in Bayankala is a kind of Carlin type gold deposit, which is the product of metallogeny in the post-collision extensional stage. The Kunnan kununahe gold, lead-zinc deposit is the product of superposition and reformation of exhalation sedimentation, and the Wulonggou gold deposit in the middle of Kunn is the product of multi-stage ore-forming superposition. The orogenic gold deposits are concentrated at 220 ~ 237 Ma.The gold main metallogenic epoch coincides with the ductile shear zone and the active age of brittle faults in the area. The skarn type mineralization occurred mainly at 240 Ma.The toketoporphyry copper-gold (molybdenum) deposit in Kun is a typical product of plate subduction stage. The ore-forming process of porphyry skarn type polymetallic deposits in the northern part of Kunming is continuous, mainly in the Middle-Late Triassic. It can be seen that the paleoTethys metallogenic belt in East Kunlun not only has a dense metallogenic zone, The characteristics of concentrated distribution, multiple types and multiple periods of superimposed mineralization, and the large scale metallogenic events coincide with the transition period of the same collision and post-collision tectonic regime during orogeny. The mixing of magmatic underplating and crust-mantle magma is the driving mechanism of orogenic belt mineralization.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.51;P542
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本文编号：1567020