兰坪金顶跑马坪铅锌矿床的三维地质结构与控矿构造  

3D geological architecture and ore-controlling structures of the Paomaping Zn-Pb deposit at the Jinding ore field,Lanping County,SE Tibetan Plateau

作　　者：薛力鹏 薛传东[1] 刘靖坤 王维 王宇 吕思猛 XUE LiPeng;XUE ChuanDong;LIU JingKun;WANG Wei;WANG Yu;LV SiMeng(Department of Earth Sciences,Kunming University of Science and Technology,Kunming 650093,China;Geological,Geophysical&Geochemical Exploration Institute of Yunnan Nonferrous Bureau,Kunming 650216,China)

机构地区：[1]昆明理工大学地球科学系,昆明650093 [2]云南省有色地质局地质地球物理化学勘查院,昆明650216

出　　处：《岩石学报》2022年第11期3531-3541,共11页Acta Petrologica Sinica

基　　金：自然资源部深地动力学重点实验室自主研究课题(J1901-4);国家重点研发计划项目(2016YFC06003、2021QZKK0301);国家自然科学基金项目(U09933605、42163007、41373049);中国地质调查局地质调查项目(1212011121065、1212011020000150011)联合资助.

摘　　要：滇西北金顶超大型铅锌矿田位于青藏高原东南缘兰坪中-新生代盆地中部,是三江成矿带中南段最典型的密西西比河谷型(MVT)矿床之一,其构造控矿和盆地流体成矿特征明显受控于印度-欧亚大陆碰撞有关的区域挤压构造。近年来,矿床浅部地质条件与资源状况已被充分揭露,但其深部地质结构、构造控矿差异性仍不清楚,这也制约了成矿预测和找矿新发现。本文以矿田东北部的跑马坪大型隐伏矿床为研究对象,利用三维地质建模及空间分析方法,识别矿化空间变化及其与断层、不整合面和地层岩性的配置关系,分析构造控矿规律及可能的流体运聚趋势。结果表明,跑马坪铅锌矿床的成矿作用与近E-W向挤压构造对中新统金顶砂泥岩(Mio-j)与上三叠统三合洞组(T_(3)s)不整合面的差异性破坏关系密切,近NS和NE向逆断层与NW向走滑-掀斜断层组合是最重要的控矿构造。其中,近NE向逆断层与不整合面是成矿流体运聚的主要通道,而近于平行的NW向走滑-掀斜断层上盘的T_(3)s高孔渗性角砾状灰岩、含灰岩角砾砂岩及裂隙带因为富含H_(2)S等还原性流体而成为与Mio-j富含金属氧化性盆地卤水混合和金属沉淀就位的最有利空间。由此,逆断层和走滑-掀斜断层组合、特定地层岩性与不整合面联合控制了流体汇聚与混合成矿作用,断层沟通了同位叠加的上三叠统油气藏储层和渐新统-中新统盆地卤水(带),这是铅锌成矿的关键。该成矿模型在金顶矿田及邻区与类似地区均具有普遍指导意义。最后,本文预测沿跑马坪矿区深部及其南北侧延伸区域还存在多条NE向隐伏控矿断层,其成矿潜力大,是下一步找矿勘查的有利靶区。The giant Jinding Zn-Pb ore field is located in the Meso-Cenozoic Lanping Basin,northwestern Yunnan Province.This is a typical Mississippi Valley-type(MVT)deposit in the central-southern segment of the Sanjiang metallogenic belt,SE Tibetan Plateau.The genesis of the ore is closely related to the compressional structures owing to the India-Eurasia continental collision.Furthermore,the compressional stress helps to bring the basinal brines to the mineralization sites.During the past six decades,numerous studies have revealed the surficial geological survey and metal-resources of the ore field,however,the deep structures and spatial variation in the ore-controlling structures of the deposits in this ore field are still unclear,which limits an effective potential prediction and/thus the finding of new metal-resources in this area.In this paper,we try to establish a 3D structural model of the concealed Paomaping Zn-Pb ore deposit,which is located in the northeastern part of the Jinding ore field.According to the varying trends of Zn,Pb concentrations,and the spatial correlation of these concentrations with the fault system,unconformities and lithological assemblages,we analyzed the mineralization sites and the probable migration pathways of the metal-bearing fluids in the deposit.The results demonstrate that all known orebodies are located in the brecciated limestones and limestone-pebble-bearing sandstones of the Upper Triassic Sanhedong Formation(T_(3)s)beneath the angular unconformity at the bottom of the Miocene Jinding sandstone-and-mudstone complex(Mio-j).The NS-or NE-trending reverse faults and their related tear faults are the major ore-controlling structures of the deposit.This fault system together with the unconformity constitute a conduit network for the mineralization fluids.The fractured rocks with high porosity and permeability of the T_(3)s along the hanging wall of the reverse faults are the most favorable traps for the mineral deposit,where episodic mixing of reduced H_(2)S-rich fluids and oxidized m

关 键 词：三维地质模型 空间分析 构造控矿 金顶跑马坪铅锌矿床 青藏高原东南缘 

分 类 号：P612[天文地球—矿床学]