青海省滩间山地区内生金属矿产成矿作用研究
发布时间：2018-09-12 13:13
【摘要】：研究区(滩间山地区)位于青藏高原柴达木盆地北缘西部,柴达木盆地北缘为我国继秦岭—大别之后的又一条超高压变质带,这条超高压变质带具有独特的地质构造背景和地质演化过程,同时,形成了中国又一条复合造山带。在漫长的地质演化时期,形成了与不同地质构造环境相对应的矿床组合,为中国西部重要的成矿带之一。在柴北缘成矿带上有著名的锡铁山超大型铅锌矿床、滩间山金龙沟大型金矿床和青龙沟金矿床等较多矿床(点)。本论文通过对研究区域内大量地质资料和科研成果的综合分析和研究,运用造山带理论对柴达木盆地北缘不同地质历史时期的地球动力学背景和演化过程进行了详细的探讨和重新厘定,建立了柴达木盆地北缘地球动力学演化模型。同时,科学的运用地学研究的现代测试方法和技术,以现代的成矿理论为指导,对所研究区域内的典型矿床进行了详细的野外地质调查工作和室内研究工作,依据所研究的结果系统的总结了柴达木盆地北缘在不同的地质历史时期和不同的区域动力学背景下的成矿作用特征。通过本文的研究结果表明:柴达木盆地北缘在新元古代即存在一个古大洋(以下简称柴北缘洋),而非部分学者认为的大陆裂谷环境,该古大洋应是始特提斯洋构造域的一部分,夹持于柴达木陆块和欧龙布鲁克微陆块之间。两个陆块并非是华北板块裂解的产物,应是罗迪尼亚大陆裂解的产物,通过分析比对已有的研究资料,我们认为,柴北缘洋打开时限至少在新元古代开始,依据Murphy的造山带理论,柴北缘洋可能存在南北双向俯冲,限于柴北缘南部柴达木盆地的巨厚沉积物覆盖,暂时未能查证到向南侧俯冲有效的证据,而向北俯冲的证据明显。新元古代大洋的形成阶段,大陆边缘主要表现为被动陆缘,新元古代末期至加里东期,柴北缘洋进入始特提斯洋构造域,洋壳俯冲作用开始体现为被动陆缘向活动陆缘的转换,形成了沟-弧-盆体系,加里东晚期大洋开始闭合,表现为由西向东的“剪刀式”闭合,发生弧陆碰撞和陆陆碰撞,同时洋壳拖拽陆壳深俯冲并开始碰撞造山,华力西期全面进入了陆内造山作用,后期发生碰撞后伸展作用。通过对滩间地区的典型矿床研究,我们进一步确认了金龙沟金矿床受变质核杂岩控矿的特征,同时在该区域通过野外地质工作首次识别并论证了受变质核杂岩控矿的独树沟金矿。金龙沟金矿床受变质核杂岩控矿的认识改变了前人认为的逆冲推覆构造控矿的观点,该变质核杂岩中与成矿密切相关的花岗斑岩年龄为356±2.8Ma,表明晚华力西期伸展构造背景下形成了与矿化密切相关的变质核杂岩。受变质核杂岩控矿的独树沟金矿成矿作用应与金龙沟金矿床一致。明确了本区内的青龙滩含铜硫铁矿为早期热水沉积成矿期与晚期矽卡岩期两期成矿作用形成的叠生矿床。万洞沟铁矿为矽卡岩型矿床,对与矿化有关的斜长花岗斑岩的进行LA-ICP-MS锆石U-Pb测年结果显示为467±3Ma,为加里东期岩浆活动的产物。青龙沟金矿为本区内晚加里东期和晚华力西期—印支期陆陆碰撞和陆内造山的结果,受多期次造山叠加作用的影响,属浅成中温造山型金矿床。红柳沟金矿床同样经历了加里东期和华力西期—印支期复合造山作用的影响,属于浅成中温造山型金矿床。加里东期与华力西期为本研究区重要成矿期:青龙滩含铜硫铁矿与万洞沟铁矿及研究区外围的锡铁山铅锌矿形成于洋壳和加里东期洋壳俯冲的构造环境;红柳沟金矿与青龙沟金矿为晚加里东期碰撞造山的过程中形成;华力西期形成了与造山后伸展作用背景下的金龙沟金矿与独树沟金矿。
[Abstract]:The study area (intertidal mountain area) is located in the western part of the northern margin of the Qaidam Basin on the Qinghai-Tibet Plateau. The northern margin of the Qaidam Basin is another ultra-high pressure metamorphic belt after Qinling-Dabie in China. This ultra-high pressure metamorphic belt has a unique geological tectonic setting and geological evolution process. At the same time, another complex orogenic belt has been formed in China. During the geological evolution period, the mineral deposit associations corresponding to different geological and tectonic environments were formed, which is one of the important metallogenic belts in Western China.There are many famous Xitieshan super-large lead-zinc deposits, Tanjianshan Jinlonggou large-scale gold deposits and Qinglonggou gold deposits in the metallogenic belt of northern Qaidam Basin. Based on the comprehensive analysis and study of geological data and scientific research achievements, the geodynamic background and evolution process of the northern margin of Qaidam Basin in different geological periods are discussed and redefined in detail by using the theory of orogenic belt, and the geodynamic evolution model of the northern margin of Qaidam Basin is established. Guided by modern metallogenic theory, this paper has carried out detailed field geological survey and laboratory research on typical deposits in the studied area, and systematically summarized the metallogenesis of the northern margin of Qaidam basin in different geological and historical periods and under different regional dynamic backgrounds. The results of this study show that there was an ancient ocean in the northern margin of Qaidam basin during Neoproterozoic (hereinafter referred to as the northern margin ocean of Qaidam basin), not a continental rift environment that some scholars believe. The ancient ocean should be a part of the Euthyan Tethyan tectonic domain, sandwiched between the Qaidam block and the Eulongbrook microcontinental block. The North Qaidam Plate is not the product of the North China Plate cracking, but the product of the Rodinia continent cracking. By analyzing and comparing the existing research data, we think that the opening time of the northern Qaidam Margin Ocean began at least in the Neoproterozoic. According to Murphy's theory of orogenic belt, the northern Qaidam Margin Ocean may have a north-south two-way subduction, which is limited to the southern Qaidam Basin in the northern Qaidam During the formation stage of the Neoproterozoic ocean, the continental margin was mainly passive. From the late Neoproterozoic to the Caledonian, the northern Qaidam margin ocean entered the Eotectic oceanic tectonic domain, and the oceanic crust subduction began to be passive. The transition from continental margin to active continental margin resulted in the formation of a trench-arc-basin system, and the ocean began to close in the late Caledonian, showing a "scissor-like" closure from west to east, arc-continent collision and continental collision. At the same time, the oceanic crust dragged the continental crust into deep subduction and began collision orogenesis. Through the study of typical deposits in the intertidal area, we have further confirmed the characteristics of the Jinlonggou gold deposit controlled by the metamorphic core complex, and for the first time identified and demonstrated the Dushugou gold deposit controlled by the metamorphic core complex in this area through field geological work. The understanding of the Jinlonggou gold deposit controlled by the metamorphic core complex has changed. The age of granite porphyry closely related to mineralization in the metamorphic core complex is 356 2.8 Ma, indicating that the metamorphic core complex closely related to mineralization was formed under the Late Variscan extensional tectonic setting. The mineralization of Dushugou gold deposit controlled by the metamorphic core complex should be one of Jinlonggou gold deposit. The Qinglongtan copper-bearing pyrite deposit in this area is a superimposed deposit formed by early hydrothermal sedimentary metallogenesis and late skarn metallogenesis. The Wandonggou iron deposit is a skarn type deposit. The LA-ICP-MS zircon U-Pb dating of the mineralization-related plagioclase granite porphyry shows that it is 467+3 Ma and is Caledonian magmatic activity. Qinglonggou gold deposit is the result of continental collision and intracontinental orogeny in Late Caledonian and Late Variscan-Indosinian epochs in this area. It is a epithermal orogenic gold deposit influenced by multi-stage orogeny and superimposition. Hongliugou gold deposit also underwent Caledonian and Variscan-Indosinian orogeny. The Qinglongtan copper-bearing pyrite and Wandonggou iron deposit and the Xitieshan lead-zinc deposit in the periphery of the study area were formed in the tectonic environment of oceanic crust and Caledonian oceanic crust subduction; the Hongliugou gold deposit and Qinglonggou gold deposit were collisional orogenic in the late Caledonian. During the Variscan period, Jinlonggou gold deposit and Dushugou gold deposit were formed under the background of post-orogenic extension.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.2
，
本文编号：2239110
[Abstract]:The study area (intertidal mountain area) is located in the western part of the northern margin of the Qaidam Basin on the Qinghai-Tibet Plateau. The northern margin of the Qaidam Basin is another ultra-high pressure metamorphic belt after Qinling-Dabie in China. This ultra-high pressure metamorphic belt has a unique geological tectonic setting and geological evolution process. At the same time, another complex orogenic belt has been formed in China. During the geological evolution period, the mineral deposit associations corresponding to different geological and tectonic environments were formed, which is one of the important metallogenic belts in Western China.There are many famous Xitieshan super-large lead-zinc deposits, Tanjianshan Jinlonggou large-scale gold deposits and Qinglonggou gold deposits in the metallogenic belt of northern Qaidam Basin. Based on the comprehensive analysis and study of geological data and scientific research achievements, the geodynamic background and evolution process of the northern margin of Qaidam Basin in different geological periods are discussed and redefined in detail by using the theory of orogenic belt, and the geodynamic evolution model of the northern margin of Qaidam Basin is established. Guided by modern metallogenic theory, this paper has carried out detailed field geological survey and laboratory research on typical deposits in the studied area, and systematically summarized the metallogenesis of the northern margin of Qaidam basin in different geological and historical periods and under different regional dynamic backgrounds. The results of this study show that there was an ancient ocean in the northern margin of Qaidam basin during Neoproterozoic (hereinafter referred to as the northern margin ocean of Qaidam basin), not a continental rift environment that some scholars believe. The ancient ocean should be a part of the Euthyan Tethyan tectonic domain, sandwiched between the Qaidam block and the Eulongbrook microcontinental block. The North Qaidam Plate is not the product of the North China Plate cracking, but the product of the Rodinia continent cracking. By analyzing and comparing the existing research data, we think that the opening time of the northern Qaidam Margin Ocean began at least in the Neoproterozoic. According to Murphy's theory of orogenic belt, the northern Qaidam Margin Ocean may have a north-south two-way subduction, which is limited to the southern Qaidam Basin in the northern Qaidam During the formation stage of the Neoproterozoic ocean, the continental margin was mainly passive. From the late Neoproterozoic to the Caledonian, the northern Qaidam margin ocean entered the Eotectic oceanic tectonic domain, and the oceanic crust subduction began to be passive. The transition from continental margin to active continental margin resulted in the formation of a trench-arc-basin system, and the ocean began to close in the late Caledonian, showing a "scissor-like" closure from west to east, arc-continent collision and continental collision. At the same time, the oceanic crust dragged the continental crust into deep subduction and began collision orogenesis. Through the study of typical deposits in the intertidal area, we have further confirmed the characteristics of the Jinlonggou gold deposit controlled by the metamorphic core complex, and for the first time identified and demonstrated the Dushugou gold deposit controlled by the metamorphic core complex in this area through field geological work. The understanding of the Jinlonggou gold deposit controlled by the metamorphic core complex has changed. The age of granite porphyry closely related to mineralization in the metamorphic core complex is 356 2.8 Ma, indicating that the metamorphic core complex closely related to mineralization was formed under the Late Variscan extensional tectonic setting. The mineralization of Dushugou gold deposit controlled by the metamorphic core complex should be one of Jinlonggou gold deposit. The Qinglongtan copper-bearing pyrite deposit in this area is a superimposed deposit formed by early hydrothermal sedimentary metallogenesis and late skarn metallogenesis. The Wandonggou iron deposit is a skarn type deposit. The LA-ICP-MS zircon U-Pb dating of the mineralization-related plagioclase granite porphyry shows that it is 467+3 Ma and is Caledonian magmatic activity. Qinglonggou gold deposit is the result of continental collision and intracontinental orogeny in Late Caledonian and Late Variscan-Indosinian epochs in this area. It is a epithermal orogenic gold deposit influenced by multi-stage orogeny and superimposition. Hongliugou gold deposit also underwent Caledonian and Variscan-Indosinian orogeny. The Qinglongtan copper-bearing pyrite and Wandonggou iron deposit and the Xitieshan lead-zinc deposit in the periphery of the study area were formed in the tectonic environment of oceanic crust and Caledonian oceanic crust subduction; the Hongliugou gold deposit and Qinglonggou gold deposit were collisional orogenic in the late Caledonian. During the Variscan period, Jinlonggou gold deposit and Dushugou gold deposit were formed under the background of post-orogenic extension.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.2
，
本文编号：2239110
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