【作者】 李蒙文；

【导师】 战明国； 毛景文；

【作者基本信息】 中国地质科学院 ， 构造地质学， 2006， 博士

【摘要】 矿床成矿系列是研究成矿作用在四维空间中的规律,探索在地球发展过程中成矿的时、空、物质的演化及其分布规律的科学理论体系。研究矿床成矿系列可以有效地指导找矿预测,促进矿产资源勘查工作的开展。本文选择天山-兴蒙造山带中段南蒙古-二连浩特-东乌旗地区和黄岗-甘珠尔庙地区开展内生金属矿床成矿系列与成矿预测研究。在充分整理和吸收消化前人大量研究成果的基础之上,选择重点矿床进行解剖,辅以岩石学和高精度同位素年代学研究,应用成矿系列理论来认识天山-兴蒙造山带中段多金属矿床的时空分布,以内生金属矿床时空分布样式作为大地构造环境的标志和限定,为天山-兴蒙造山带中段大型多金属矿集区的战略靶区优选提供理论依据。在详细分析前人研究成果的基础上,提出本区经历了新元古代至晚古生代末古亚洲洋盆形成与闭合阶段、中生代-新生代滨西太平洋大陆边缘板内构造发育阶段。在充分考虑成矿时间的统一性和时序的演化性、区域地质构造演化与区域成矿演化关系基础上,结合地质、地球物理、地球化学、遥感资料,对研究区进行了成矿区带划分,共划分两个成矿区带:北部为南蒙古-二连浩特-东乌旗铜、钼、金、铁、锌、钨、铅、铬成矿带;南部为黄岗-甘珠尔庙锡、钨、铜、铅、锌、铍、银、铁、铌(钽)成矿带。按照矿床成矿系列的学术指导思想,在二个成矿带内对矿床进行了研究,共划分为四个成矿系列,二个成矿亚系列。1、南蒙古-二连浩特-东乌旗成矿带划分了三个矿床成矿系列:Ⅰ、索伦山-贺根山晚泥盆世-早石炭世与洋壳超基性-基性岩(蛇绿岩)有关的岩浆岩型铬、铁矿床成矿系列(Ⅰ);Ⅱ、南蒙古地区晚泥盆世-早石炭世与中酸性侵入岩有关的铜、钼、金矿床成矿系列(Ⅱ);Ⅲ、二连浩特-东乌旗地区燕山期与花岗岩有关的铁、锌、铅、铜、金、钨、银矿床成矿系列(Ⅲ);2、黄岗-甘珠尔庙成矿带划分了一个矿床成矿系列,其中包含二个成矿亚系列:黄岗—甘珠尔庙地区燕山期与酸性—中酸性侵入岩有关的锡、钨、铜、铅、锌、铍、银、铁、铌(钽)矿床成矿系列(Ⅳ),该成矿系列包含二个成矿亚系列,即:①黄岗-甘珠尔庙地区燕山期与酸性侵入岩有关的钨、锡多金属矿床成矿亚系列;②黄岗-甘珠尔庙地区燕山期与中酸性侵入岩有关的铅、锌多金属矿床成矿亚系列。对研究区内不同成矿系列的典型矿床进行了解剖,详细描述了贺根山铬铁矿床、欧玉陶勒盖铜(金)矿床(蒙古国)、朝不楞矽卡岩型铁多金属矿床、沙麦热液型黑钨矿-石英脉钨矿床、大井锡多金属矿床和白音诺尔铅锌矿床的成矿区域地质构造背景、矿床地质、同位素、微量元素、稀土元素、包裹体测温等内容,论述了矿床之间的差异性和内在联系。根据控矿因素和成矿规律,确立了五个区域成矿模式。从成矿构造环境、深部流体、壳幔相互作用、地质事件等方面探讨了成矿的控制因素,并分析了矿床时空分布规律。研究认为深部流体的积极参与以及地幔物质不均一性与本区大型矿集区的形成在物质上具有耦合关系。中生代构造-岩浆岩带是矿床的集中分布区。矿床的时间分布规律清楚地表明研究区内矿床集中分布于晚泥盆世-早石炭世和晚中生代二个阶段。其中,晚中生代是最重要的成矿期,这与中国北方中生代140Ma左右的构造体制大转换和120Ma左右的岩石圈减薄过程密切相关。认为370～320Ma成矿事件与洋壳俯冲、削减作用之间的藕合构成了本区第一、第二成矿系列;140Ma左右成矿事件与构造体制大转换之间的藕合构成了本区第四成矿系列;120Ma左右成矿事件与岩石圈减薄过程之间的藕合构成了本区第三成矿系列。根据我国矿产资源的需求状况和本研究的主攻目标及内蒙古各成矿区带的实际,确定对金、银、铜、铅、锌、锡、钨、钼等进行成矿预测和远景评价。圈定了五个B类成矿预测区,即查干敖包庙铜(银)多金属成矿预测区(V-1)、达来庙铜(银)多金属成矿预测区(V-2)、奥尤特铜(银)多金属成矿预测区(V-3)、查干陶勒盖—朝不楞东银铜多金属成矿预测区(V-4)、黄岗-甘珠尔庙地区钨锡铅锌多金属成矿预测区(V-5)。将二连浩特-东乌旗一带的成矿地质条件同南蒙古地区进行了对比,认为二连浩特-东乌旗一带具有较好的成矿条件,但在成矿元素组合方面与南蒙古地区似有差异。南蒙古地区主要产出与晚古生代中酸性侵入岩有关的斑岩型铜(金)、铜(钼)矿床,矿床规模较大,成矿元素组合相对简单;而在二连浩特-东乌旗一带,从目前发现的矿床(点)来看,其成矿元素组合较为复杂,成矿时间主要为晚古生代与晚中生代,但以晚中生代矿床规模大、数量多,这可能与该区较南蒙古地区更多地受到滨西太平洋构造-岩浆-成矿事件的强烈叠加有关。因此,在该区开展找矿勘查工作即要看到与南蒙古地区的相似性,又要注意其特殊性。更多还原

【Abstract】 Metallogenic series study mainly is to reveal the laws of metallogenic processes in the four-dimension space, and deduce the relationship between the earth evolution and the distribution of the material constituting the earth. Such study has greatly improved our recognition of the global geologic laws, besides it also promoted exploration of the mineral resource. This dissertation mainly tries to study Metallogenic Series and Prognosis of Endogenetic Metallic Deposits in the South Mongolia-Erlianhaote-Dongwuqi district and the Huanggang-Ganzhuermiao district in the middle section of Tianshan-Xingmeng orogenic belt. My study based on the previous researches, conducting a detailed analysis on some important deposits where petrological and isotopic dating methods are employed to research the spatial and temporal distribution of the polymetallic deposits in the Tianshan-Xinmeng orogenic belt according to the metallogenic theory. The distribution pattern of various types of endogenic polymetallic deposits was thought as the marker and restriction condition of the variable tectonic setting, which provides a theoretical background to select optimum targeted large-scale polymetallic-intensive deposits in the middle section of the Tianshan-Xingmeng orogenic belt.The Tianshan-Xingmeng orogenic belt was formed mainly by the opening and closure of the Paleo-Asian Ocean from Neoproterozoic to Later Paleozoic, and then overprinted by the intra-plate structure along the continental margin of the west Circum-Pacific tectonic belt from Mesozoic to Cenozoic. Based on detailed analyses upon the tectonic and metallogenic evolution histories, we found a strong and complicated relationship between the tectonic evolution and metallogenic evolution both in space and time. As the result, we define two metallogenic belts in the area taking into account the geologic, geophysics and geochemistry, and remote sensing data: (1) Cu, Mo, Au, Fe, Zn, W, Pb, Cr metallogenic belt in the South Mongolia-Erlianhaote-Dongwuqi district to the north; and (2)Sn, W, Cu, Pb, Zn, Be, Ag, Fe, Nb(Ta) metallogenic belt in the Huanggang-Ganzhuermiao district to the south.After summarizing the characteristics of deposits and associated their tectonic setting, totally four metallogenic series and sub-metallogenic series are defined in the two metallogenic belts of the studied area according to the theory of metallogenic series:1. Three metallogenic series in the South Mongolia-Erlianhaote-Dongwuqi Metallogenic belt are as following:Ⅰ. The Later Devonian to the Early Carboniferous Magma-type Cr-Fe deposits complex related to ultramafic or mafic rock (ophiolite-type) in the Suolunshan -Hegenshan(Ⅰ).Ⅱ. The Later Devonian to Early Carboniferous Intermediate-acid granitoids-related Cu-Au-Mo deposits complex in the South Mongolia(Ⅱ).Ⅲ. The Yanshanian Granitoids-related Fe-Zn-Pb-Cu-Au-W-Ag deposits complex in the Erlianhaote-Dongwuqi district(Ⅲ).2. One metallogenic series is defined in the Huanggang-Ganzhuermiao Metallogenic belt, including two sub-metallogenic series.The Yanshanian Acid to intermediate-acid granitoids-related Sn-W-Cu-Pb- Zn-Be-Ag-Fe-Nb(Tb) deposits complex in the Huanggang-Ganzhuermiao district(Ⅳ), which is consisted of a Yanshanian Acid granitoids-related Sn-W deposits complex in the Huanggang-Ganzhuermiao district and a Yanshanian intermediate-acid granitoids-related Pb-Zn deposits complex in the Huanggang-Ganzhuermiao district.We carried out a detailed analysis of the typical deposits of different metallogenic series, especially the geological settings and ore-bearing structure in the Hegenshan Cr-Fe deposit, Oyu Tolgoi Cu-Au porphyry deposit, Chaobuleng skarn-type Fe polymetallic deposit, Shamai hydrothermal wolframite-quartz-vein W deposit, Dajing Sn polymetallic deposit, and Baiyinnuoer Pb-Zn deposit. Employing various methods of geological analyses such as isotopic geology, geochemistry, and inclusion-thermometric method, we documented the identity and differences of variable deposits.In the light of ore-control factors and metallogenic rules, Five regional metallogenic models have been established.From the view point of ore-controlling factors such as ore-bearing structure, mantle fluid, and interaction of crust and mantle, geological events, we have analyzed the spatial and temporal characteristics of ore distribution, concluding that the participation of the mantle fluid, as well as the heterogeneity of mantle-sourced material is strongly coupled in the ore mass-source with the formation of the large-scale deposit-intensive area. The Mesozoic tectono-magmati crock belt is a deposit-riched area. Geo-chronological data clearly demonstrated that the deposits formed mainly in two stages: Later Devonian to Early Carboniferous and Later Mesozoic. The later one is closely related to the Mesozoic tectonic transition event (140Ma) and the lithospheric thinning process (120Ma) in the North China. we consider that the coupling between the metallogenic event from 370Ma to 320Ma and the subduction of oceanic crust formed the first and second metallogenic series, and the coupling between the metallogenic event about in 140Ma and the large transition of tectonic system formed the fourth metallogenic series, and the coupling between the metallogenic event about in 120Ma and the process of lithospheric thinning formed the third metallogenic series in this area.In order to keeping up the Chinese requirement for mineral resource and the major goal of this study, we predicted and evaluated the prospect of Au, Ag, Cu, Pb, Zn, Sn, W and Mo deposits in the studied area based on the characteristics of the metallogenic belts in inner Mongolia. Total five B-grade potential areas, including Chaganaobaomiao Cu(Ag) polymetallic prospect(Ⅴ-1), Dalaimaio Cu(Ag) polymetallic prospect(Ⅴ-2), Aoyoute Cu(Ag) polymetallic prospect(Ⅴ-3), Chagantaolegai-Chaobuleng Ag-Cu polymetallic prospects(Ⅴ-4), Huanggang-Ganzhuermiao W-Sn, Pb-Zn polymetallic prospect(Ⅴ-5) are defined in the dissertation.Comparing the ore-froming geological conditions of the Eelianhaote-Dongwuqi area with those of the South Mongolia area, we believe that Erlianhaote-Dongwuqi area is also of advantage for economic ore deposits same as the South Mongolia. But their ore-forming elements assemblage is different. The deposits in the South Mongolia are mainly porphyry-related Cu(Au)-Cu(Mo) deposits hosted in the Later Paleozoic intermediate and acid granitoids with a much larger scale and relatively simple mineral assemblage. On the other hand, the deposits in the Erlianhaote-Dongwuqi area have a very complicated mineral assemblage and they were formed mainly in the Later Paleozoic and Later Mesozoic according to identified deposits and occurrences. The majority of economic deposits were mainly formed in Later Mesozoic, which is very likely related to the strong superimposing events of the west Circum-Pacific tectogenesis–magmatism–metallogenesis upon the eastern segment of the Paleozoic Tianshan-Xinmeng orogenic belt. In conclusion, during our reconnaissance in the Erlianhaote-Dongwuqi area, we should notice the similarities between the Erlianhaote-Dongwuqi and South Mongolia areas. More important, we also should pay more attention to the particularities in the Erlianhaote-Dongwuqi area.更多还原