新疆大地构造单元划分及成矿作用

【研究目的】新疆横跨古亚洲洋、特提斯洋两大构造成矿域,长期的洋-陆转换过程造就了独具特色的地壳增生史和复杂多样成矿作用。作为中国能源、有色、铁矿、钾盐和非金属的重要资源基地,截止2019年底,新疆已发现矿产152种,建设矿山3000余座,形成了一批以石油、天然气、煤炭、铁、锰、铅、锌、铜、镍、金、锑、铀、稀有金属、萤石、钾盐等优势矿种为主的勘查开发基地。为进一步解析新疆多阶段、多旋回的地壳生长过程与成矿作用的耦合关系,亟需开展新疆大地构造单元划分研究,以期更精准地开展成矿预测评价,更好地服务国家能源资源安全战略。【研究方法】在对全疆沉积建造、火山建造、侵入岩建造、变质建造、构造变形、成矿规律等方面综合分析的基础上,以“洋板块地质学思想”为统领、以增生造山过程的解析为主要手段,结合不同构造背景下的成矿响应,提出新的全疆构造单元划分方案。【研究结果】全疆划分出一级构造单元6个、二级构造单元14个、三级构造单元32个以及四级构造单元99个。提出以塔里木克拉通为界,以北属古亚洲洋构造域,以南属特提斯洋构造域。并根据新疆地壳演化与成矿作用关系,划分出4个构造-成矿阶段。【结论】将全疆构造-成矿旋回划分为太古宙—古元古代古陆核的形成与铁-铜成矿阶段、中元古代—新元古代中期塔里木古陆及古生代洋中陆块基底的形成与铁-铅锌-磷灰石-石棉-宝石-石英岩成矿阶段、南华纪—三叠纪大陆地壳的增生与聚合及石油-天然气-金-铜-镍-铅锌-铁-锰-锑-钨-钼-稀有金属-石棉-石墨-云母-红柱石-宝石成矿阶段、侏罗纪至今的盆山构造形成与演变及石油-天然气-煤-铀-铅锌-盐类成矿阶段。创新点：（1）以洋板块地质学理论为指导,结合不同构造环境的成矿专属性,提出了新疆“三系两带一块”的大地构造新格局。（2）新疆矿床类型以岩浆热液型、生物化学沉积型、化学沉积型、海相火山岩型、岩浆型、变成型等为主。（3）全疆划分出4个构造-成矿阶段,提出了“三系两带一块一缘”的成矿理论新认识,认为中生代成矿作用是新疆今后地质勘查找矿的主攻成矿期。

Subdivision of tectonic units and its metallogenesis in Xinjiang

This paper is the result of mineral exploration engineering.Objective]Stretched across the Paleo-Asian Ocean and the Paleo-Tethys Ocean, the long-term ocean-land transformed process of Xinjiang Region has created a unique history of crustal accretion and diverse mineralization. As an important resource base for energy, nonferrous metals, iron ore, potash, and non-metals in China, there are 152 kinds of minerals had been discovered and over 3000 mines had been built in Xinjiang. Furthermore, abundant exploration and development bases, dominated by dominant minerals including oil, natural gas, coal, iron, manganese, lead, zinc, copper, nickel, gold, antimony, uranium, rare metals, fluorite, potassium salt, etc, have been formed by the end of 2019. For further analyzing the coupling relationship between multi-stage and multi-cycle crustal growth process and mineralization in Xinjiang, the research on division of tectonic units in Xinjiang is expected for more accurate metallogenic prediction and evaluation, and is urgent for better serving the national energy and resource security strategy.Methods]Based on the comprehensive analysis of sedimentary formation, volcanic formation, intrusive formation, metamorphic formation, structural deformation, and metallogenic regularity in Xinjiang, a new division scheme of tectonic units in Xinjiang is put forward under the guidance of "Ocean Plate Geology" and the analysis of accretionary orogenic process, combined with the metallogenic response under different tectonic backgrounds.Results]The new structural unit division scheme includes 6 primary structural units, 14 secondary structural units, 32 tertiary structural units, and 99 quaternary structural units. It is proposed that the Tarim craton is bounded by the Paleo-Asian Ocean tectonic domain in the north and the Tethys Ocean tectonic domain in the south. According to the relationship between crustal evolution and mineralization in Xinjiang, the metallogenic theory of "three systems, two belts, one block, and one edge" is creatively proposed.Conclusions]Four tectonic metallogenic stages in Xinjiang are systematically proposed, including the formation of the Archean to Paleoproterozoic ancient continental core with iron-copper metallogenic stage, the formation of the middle-Proterozoic to middle-Neoproterozoic Tarim ancient basement and the Paleozoic ocean continental block with iron-lead-zinc-apatite-asbestos-gem-quartzite metallogenic stage, the accretion and aggregation of continental crust in Nanhua to Triassic with oil-gas-gold-copper-nickel-lead-zinc-iron-manganese-antimony-tungsten-molybdenum-rare metals-asbestos-raphite-mica-andalusite-gem metallogenic stage, and the formation and evolution of basin mountain structures from Jurassic to present with oil-gas-coal-uranium-lead-zinc-salt metallogenic stage.Highlights: (1) Guided by "the theory of Ocean plate geology" and combined with the metallogenic specificity of different tectonic environments, a new tectonic pattern of "three systems, two belts, and one block" in Xinjiang is put forward. (2) The deposit types in Xinjiang are mainly magmatic hydrothermal type, biochemical sedimentary type, chemical sedimentary type, marine volcanic rock type, magmatic type, and metamorphic type. (3) There are four tectonic metallogenic stages are divided, and a new metallogenic theory of "three systems, two belts, one block, and one edge" is creatively proposed in Xinjiang. The Mesozoic mineralization is considered as the main metallogenic period of geological exploration and prospecting in Xinjiang in the future.