辛后田, 邢德和, 刘超, 刘航, 王文清, 李永飞, 刘琦, 杨佳林. 辽吉构造带钴-镍成矿地质背景及找矿方向[J]. 地质与资源, 2024, 33(4): 447-466. DOI: 10.13686/j.cnki.dzyzy.2024.04.003
    引用本文: 辛后田, 邢德和, 刘超, 刘航, 王文清, 李永飞, 刘琦, 杨佳林. 辽吉构造带钴-镍成矿地质背景及找矿方向[J]. 地质与资源, 2024, 33(4): 447-466. DOI: 10.13686/j.cnki.dzyzy.2024.04.003
    XIN Hou-tian, XING De-he, LIU Chao, LIU Hang, WANG Wen-qing, LI Yong-fei, LIU Qi, YANG Jia-lin. GEOLOGICAL SETTING AND PROSPECTING DIRECTION OF COBALT-NICKEL MINERALIZATION IN LIAONING-JILIN TECTONIC BELT[J]. Geology and Resources, 2024, 33(4): 447-466. DOI: 10.13686/j.cnki.dzyzy.2024.04.003
    Citation: XIN Hou-tian, XING De-he, LIU Chao, LIU Hang, WANG Wen-qing, LI Yong-fei, LIU Qi, YANG Jia-lin. GEOLOGICAL SETTING AND PROSPECTING DIRECTION OF COBALT-NICKEL MINERALIZATION IN LIAONING-JILIN TECTONIC BELT[J]. Geology and Resources, 2024, 33(4): 447-466. DOI: 10.13686/j.cnki.dzyzy.2024.04.003

    辽吉构造带钴-镍成矿地质背景及找矿方向

    GEOLOGICAL SETTING AND PROSPECTING DIRECTION OF COBALT-NICKEL MINERALIZATION IN LIAONING-JILIN TECTONIC BELT

    • 摘要: 针对辽吉构造带内钴-镍矿找矿问题,从古元古代构造-建造等成矿地质条件入手,在充分分析前人资料和总结前期研究成果的基础上,对辽吉构造带钴-镍成矿物质来源、典型矿床(点)矿体特征、成矿作用进行了系统论述. 研究表明,原辽河群浪子山组到高家峪组是由稳定大陆边缘、活动大陆边缘乃至沟弧盆体系背景形成的复杂造山带增生岩系,不同成因岩片间均为构造接触,显示“总体无序、局部有序”的构造地层特点;上覆大石桥组-盖县组为稳定的残余海盆沉积,与下伏“地层”非整合接触,显示有序地层的特点. 总体来看,该套“地层”既不能按有序地层简单划分,也不能以变质变形程度进行区域对比,一些变质岩石的原岩建造及其形成的大地构造环境仅依靠地球化学数据、图解来判断也是极不可靠的. “辽吉花岗岩(条痕状或条带状花岗岩)”是相对成熟的陆缘弧、岛弧岩石组合,主体显示TTG特征,其控矿意义尚不清楚;造山期后伸展作用下形成的侵入岩多为同构造期的深熔(重熔)的(含)石榴石花岗岩或花岗质片麻岩(S型)和造山晚期加厚背景下的具埃达克性质的花岗闪长岩. 区域铜钴镍矿的成矿物质主要来源于基性岩脉(墙)、陆壳火山碎屑岩、古洋壳残余的俯冲增生杂岩及远洋沉积岩等4种类型. 在辽吉洋俯冲消亡过程中,原始矿源层受造山作用、变质作用影响再富集成矿,伸展作用下的基性-超基性成矿,除此之外,远洋环境中较高的碳质和盐度(海底热卤水)对矿产的富集也是不可或缺的因素. 结合区域地球化学特征,在辽吉构造带划分出3个钴-镍矿成矿带及6个找矿靶区,提出了辽吉构造带钴-镍的找矿标志及找矿方向,分析了成矿潜力,为后期区域找矿突破战略行动提供了新思路.关键词:辽吉构造带;钴-镍矿;古元古代;沟-弧-盆体系;辽吉洋;找矿预测

       

      Abstract: The paper focuses on the prospecting of cobalt-nickel deposits in Liaoning-Jilin tectonic belt, on the basis of metallogenic geological conditions such as Paleoproterozoic structure-formation, to analyze previous data and research results and systematically discuss the sources of cobalt-nickel ore-forming material, characteristics of typical ore deposits or occurrences and mineralization process in Liaoning-Jilin tectonic belt. The results show that the Langzishan Formation to Gaojiayu Formation of former Liaohe Group is a complex orogenic accretionary series formed under the stable continental margin, active continental margin and even trench-arc-basin system. There is structural contact between the rock slices of different origin, showing the tectonic formation characteristics of overall disorder and locally order. The overlying Dashiqiao Formation-Gaixian Formation is stable residual sea basin sediment, which are in non-conformable contact with the underlying strata, showing the characteristics of ordered strata. Overall, the set of formation can neither be simply divided as ordered strata, nor be regionally correlated by metamorphic deformation degree. It is quite unreliable to judge the protolith formation of some metamorphic rocks and the tectonic environment in which they formed only by geochemical data and diagrams. The Liao-Ji granite(streaky or banded granite) formed by relatively mature continental margin arc, and the rock assemblage of the island arc generally displays the characteristics of TTG, but its ore-controlling significance is still unclear. The intrusive rocks formed under post-orogenic extension are predominantly syntectonic garnet granites or granitic gneisses which were deeply melted or remelted S-type granite. Additionally, there are adakitic granitic diorites that emerged in the context of late orogenic thickening. The ore-forming materials of the Cu, Co and Ni deposits are primarily sourced from basic dykes, continental crust pyroclastic rocks, subduction accretion complexes and abyssal sedimentary rocks. In the process of subduction and extinction for the Liao-Ji Ocean, besides the re-enrichment of original mineral source layer by orogeny and metamorphism, and the mineralization of basic-ultrabasic rocks under extensional action, the high carbonaceous quality and salinity in pelagic environment(seafloor thermal brines) are essential factors for mineral enrichment. In conjunction with regional geochemistry, three cobalt-nickel mineralization zones and six target areas are delineated within the Liaoning-Jilin tectonic belt. With an evaluation for the mineralization potential, the prospecting indicators and directions for cobalt-nickel deposits in the belt are proposed, which offer a novel approach to the prospecting breakthrough strategic action in the region.

       

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