矿田构造与岩浆热力构造的类型划分及青海实例分析

活动有一定联系，形成于岩浆岩体中或围岩地层中或远程热力作用影响区的一系列热力（含部分应力作用）形成的构造类型。在矿田、矿田地质和矿田构造的概念及类型划分研究基础上，提出了矿田构造和岩浆-热力构造的类型划分方案。按成矿期构造形成的主控作用方式，将矿田构造划分为：应力、热力、重力和复合转化4种构造类型。按照矿田岩浆活动-热力作用对成矿作用的控制影响深度、构造环境和成矿类型，将矿田岩浆-热力构造分为五大类24个亚类：①近地表热水喷流沉积-地热异常群集型；②热液型；③岩浆侵入-斑岩-矽卡岩-韧性剪切流变-热穹窿型；④岩浆通道-小岩体矿床-壳幔混合成矿型；⑤地幔热柱型。这些不同深度的岩浆-热力构造形成了不同类型的矿床，在壳幔岩浆-热力构造作用下，经常形成重要矿床类型组合和超大型矿床。对盐丘、岩浆热穹窿、地热异常、壳幔热柱等几种特殊类型的岩浆-热力构造进行了简要的特征分析。以青海祁漫塔格矿带景忍—虎头崖多金属矿田为实例，在矿田地质学指导下， 以矿田建造和构造-岩相填图为基础，剖析矿区岩浆-热力构造特征，归纳其岩浆-热力构造类型为斑岩型+矽卡岩型+断控热液型，认为晚三叠世岩浆侵入作用是该区多金属大规模成矿的主要内因，岩浆侵入作用与各时代碳酸盐岩接触带形成了矽卡岩矿床，并且显示出印支期岩浆侵入体、斑岩、矽卡岩带、多组断裂破碎带和热液蚀变带的发育与找矿富集中心紧密套合，不同方向断裂控矿作用不同，近EW向和NWW向断裂控矿显著，矿田中深部成矿潜力较大。

关键词： 矿田构造；岩浆-热力构造；成矿类型；成矿深度；找矿富集中心；景忍—虎头崖矿田

中图分类号： P613；P623.3；P548 文献标志码： A

Abstract： Based on a lot of orogenic belts and basin orefields in the western and middle parts of China， the characteristics of thermal action and thermal structure are extensive and special. Magma-thermodynamic structure is a series of thermal structure formed in magma body or wall rock stratum or the area influenced by remote thermal action， and connected with magmatic intrusions or volcanic eruption by controlling of magma-thermal action. Based on the concepts and type classification of orefield， orefield geology and orefield structure， the scheme for type classification of orefield structure and magma-thermodynamic structure were studied. According to the main controlled action formed by the structure in the epoch of mineralization， orefield structure was divided into stress， thermodynamic， gravity and combined transformed structures. According to the controlling effect of orefield magma-thermodynamic action on the mineralization depth， tectonic environment and metallogenic type， orefield magma-thermodynamic structure was divided into 5 categories and 24 sub categories. The 5 categories include： ①the near-surface sedimentary exhalative-geothermal anomaly cluster type； ②hydrothermal type； ③magma intrusion-porphyry-skarn-ductile shear-thermal dome type； ④magma conduit-small rock body deposit-crust mantle mixed metallogenic type； ⑤mantle plume type. These different depths of magma-thermodynamic structure actions form different types of deposits； under the action of crust mantle magma-thermodynamic structure， the important mineralization types and super large-scale ore deposits are usually formed. The magma-thermodynamic structure including salt dome， magma diapers thermal dome， geothermal abnormal， crust mantle plume were analyzed in brief. Jingren-Hutouya polymetallic orefield of Qimantage metallogenic belt of Qinghai， the western China was taken as an example. According to the theory of orefield geology， based on orefield formation and structure-lithofacies geological mapping， the characteristics of magma-hydrothermal structure in the mine are porphyry+skarn+hydrothermal controlled by faults. The results show that Late Triassic magma intrusions are the main internal factors of large-scale polymetallic mineralization； the magmatic intrusion and carbonate rock contact zones in different stages form the skarn deposit； Indosinian magmatic intrusions， porphyry， skarn， multigroup faulted fracture zones and hydrothermal alterations belts develop nearly in the same place with the mineralization eichment center； the ore-controlling effects of faults in different directions are not the same， and the near-EW and NWW faults are obvious； metallogenetic potentiality in the middle and deep parts of orefield is great.

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