青海循化地区区域地质特征及成矿地质背景研究

发布时间：2018-03-26 22:31

本文选题：秦祁结合部　切入点：循化地区　出处：《长安大学》2015年硕士论文

【摘要】：青海省循化地区处于中央造山系中段祁连造山带与西秦岭造山带接合部位,在早古生代与晚古生代-早中生代经历了复杂、多期的构造-岩浆-沉积作用,为多种金属成矿作用提供了有利的地质背景条件及成矿环境。成矿作用具有多期、多矿种和多类型的特点。该区段矿种多,矿床类型复杂,成矿时代跨度大,成矿地质条件独特,已发现了矿(化)点十余处,是青海省东部地区重要的金属矿产地之一。论文以板块构造和区域成矿理论为指导,通过实地野外考察,并结合研究区内以往地质矿产资料,开展对循化地区区域地质特征和成矿地质背景研究,系统总结了循化地区不同地质时期、不同动力学背景下矿床的成矿地质条件、控矿因素,探讨其成矿地质背景及成矿规律,指出本区的重要找矿标志,对进行区域成矿预测有着重要的地质意义。主要取得以下认识和进展:1、对研究区内主要含矿层位重新划分。将区内化隆岩群划分为两个岩性段,并于其中厘定出一套变火山岩系,暂归为寒武系六道沟组;将三叠系隆务河组地层沉积组合划分为灰岩段、砾岩段、细碎屑岩段、韵律组合段、粉砂质板岩段五段。将成矿关系密切的加里东期、印支期岩浆岩划分为若干侵入体。2、研究区横跨祁连、秦岭两大成矿带,北部南祁连化隆微地块以加里东期为主要的成矿期,主要发育岩浆熔离型铜镍矿床、伟晶岩型稀有金属、非金属矿床,其成矿作用与俯冲地质背景密切相关。南部西秦岭西段北缘以印支期为主要成矿期,主要发育斑岩型、矽卡岩型、构造蚀变岩型多金属矿床,形成于中-晚三叠世活动大陆边缘向陆-陆碰撞造山的构造转换体制之下。3、北部南祁连化隆微地块内矿床主要分布在侵位于变质地层(化隆岩群)中的镁铁—超镁铁岩带及伟晶岩脉内,以镁铁—超镁铁岩及脉岩为直接找矿标志;西秦岭西段北缘矿床主要分布于中酸性岩体外围,及其与围岩接触带部位,以中酸性侵入岩与碳酸盐岩接触带、北西向与北东向断裂交汇部位及岩脉为重点找矿方向。二者均受地层、构造、岩浆岩的综合控制。综合研究认为,南祁连化隆微地块化隆镁铁—超镁铁岩带为岩浆熔离型铜镍矿成矿远景区,西秦岭西段北缘岗察一带为斑岩型、矽卡岩型铜、金、铁矿成矿远景区。
[Abstract]:The Xunhua area of Qinghai Province is located at the junction of the Qilian orogenic belt and the West Qinling orogenic belt in the central orogenic system, and has experienced complex and multi-stage tectonic-magmatic sedimentary processes in the early Paleozoic and the late Paleozoic to early Mesozoic. It provides favorable geological background and metallogenic environment for many kinds of metallization. The metallogeny has the characteristics of multi-period, multi-type and multi-type. This section has many kinds of ore, complex deposit types and a long span of metallogenic epoch. The ore-forming geological conditions are unique and more than ten ore (chemical) points have been discovered, which is one of the important metal mineral deposits in eastern Qinghai province. The paper is guided by plate tectonics and regional metallogenic theory, and through field investigation, Combined with the past geological and mineral resources data in the study area, the regional geological characteristics and metallogenic geological background of the Xunhua area are studied, and the metallogenic geological conditions of the deposits in different geological periods and different dynamic backgrounds in the Xunhua area are systematically summarized. The ore-controlling factors are discussed, the metallogenic geological background and metallogenic regularity are discussed, and the important prospecting marks in this area are pointed out. It is of great geological significance for regional metallogenic prediction. The following knowledge and progress have been obtained. The main ore-bearing strata in the study area have been reclassified. The Hualong rock group in this area is divided into two lithologic segments. The sedimentary assemblages of the Triassic Longwuhe formation are divided into limestone, conglomerate, fine clastic rock and rhythmic assemblage, and a set of metamorphic rocks is determined, which is temporarily classified into the Liudaogou formation of Cambrian, and the stratigraphic sedimentary assemblage of Longwuhe formation of the Triassic system. The magmatic rocks of Caledonian and Indosinian periods, which are closely related to mineralization, are divided into several intrusions. The study area spans Qilian, Qinling two major metallogenic belts, and the Caledonian stage is the main metallogenic stage in the South Qilian Hualong microblock in the north. Magmatic melting type copper-nickel deposit, pegmatite type rare metal deposit and nonmetallic deposit are mainly developed. Their mineralization is closely related to the subduction geological background. The northern margin of the western part of the western Qinling Mountains in southern China is dominated by the Indosinian epoch and the porphyry type. Skarn type, structural altered rock type polymetallic deposit, Formed under the framework of tectonic transformation from the active continental margin to the continental collision orogeny in the Middle and late Triassic, the deposits in the Hualong microblock, South Qilian, in the north, are mainly distributed in the magnesite supercharged in the transgressive metamorphic strata (the Hualong rock group). In the mafic belt and pegmatite veins, Taking the mafic ultramafic rock and dike rock as the direct prospecting marker, the deposits in the northern margin of the western Qinling Mountains are mainly distributed in the periphery of the intermediate-acid rock mass and its contact zone with the surrounding rock, and the contact zone between the intermediate-acid intrusive rock and the carbonate rock, and the contact zone between the intermediate-acid intrusive rock and the carbonate rock. The intersection of NW and NNE faults and the dike are the key prospecting directions. Both of them are controlled comprehensively by strata, structures and magmatic rocks. Magnesium-ultramafic rock belt of Hualong micro-block in South Qilian is a magmatic melting type copper-nickel metallogenic area, the northern part of west Qinling is porphyry type, skarn type copper, gold and iron ore metallogenic area.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P56;P612

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