【作者】 李根军；

【导师】 吴国学； 姜琦刚；

【作者基本信息】 吉林大学 ， 矿产普查与勘探， 2012， 硕士

【摘要】 安第斯成矿带是环太平洋成矿带的重要组成部分，其成岩成矿时代晚，主要集中在中-新生代。形成的矿床遭到外力的影响作用小，在遥感图像上能够清晰的反映矿床所在区域的成矿地质环境，尤其在玻利维亚托波西地区东北部，各类型矿床呈带状分布明显，集中产出于东科迪勒拉褶皱带与普纳高原的接触带及其两侧。故选择玻利维亚托波西地区东北部为研究区，进行遥感地质信息提取及成矿预测研究。本文在总结玻利维亚波托西地区区域地质资料的基础上，运用ETM+/ASTER遥感数据，解译研究区的线性构造、环形构造、岩体及地层等遥感地质信息，并且通过遥感图像处理技术提取矿化蚀变信息，深入分析该区域斑岩型矿床的控矿因素和遥感找矿标志，重点研究典型矿床的遥感地质特征，总结成矿规律，建立斑岩型矿床的地质-遥感找矿模型，进行成矿预测。通过系统地分析研究，得出以下成果：1.区域遥感线性构造以近南北向和北北西向为主。在遥感图像上，近南北向断裂构造表现为火山岩体呈直线状排列，为火山岩带与沉积地层的接触带，控制着地层和岩体的展布，是研究区内主要的导矿构造；北北西向断裂表现为直线状沟谷，切割深，走向稳定，是地层在压应力作用下形成的压扭性断裂，为主要的控矿构造。北东东向断裂，其规模小，在遥感图像上表现为地层的错位，根据断裂之间的切割关系，为晚期的平移断层。火山穹丘内部的放射状断裂呈”V”字形，其沟谷切割深，是主要的容矿构造。2.在研究区内，环形构造是由岩浆活动形成的火山穹丘。在遥感图像上，表现为突起的正地形，环形影像表现的很明显。火山穹丘中心部位的岩体为中酸性斑岩体，时代为新近纪，斑岩体与早期形成的岩体发生强烈的蚀变作用，形成明显的矿化蚀变分带。外围岩体中放射状的线性构造显示出，早期的侵入岩体受到晚期侵入体的侵位作用，致使其发生破裂。这些放射状的裂隙为成矿物质的聚集提供了有利的场所。3.研究区东部和西北部的褶皱构造很发育，向斜构造的核部主要为新近纪和第四纪的松散堆积物构成，两翼地层由志留纪和白垩纪的砂岩及粉砂岩地层构成。该区域的沉积型矿床和层控型矿床明显受到褶皱构造的控制，表现出顺层展布的特点。4.运用ASTER数据，采用波段比值和主成分分析的方法提取出类蚀变信息：铁氧化物类蚀变、泥化类蚀变和青磐岩化蚀变。在研究区的中部，侵入岩和火山熔岩产出的部位，铁氧化物类蚀变很强烈，呈带状近南北向分布；泥化类蚀变在火山穹丘和研究区东部的白垩系地层中很强烈；青磐岩化蚀变的分布与铁氧化物类蚀变相同，主要分布在火山熔岩及中酸性侵入岩体产出的部位。5.在对研究区线性构造、环形构造，岩体和地层的分析以及蚀变信息提取的基础上，结合区域矿产分布，对研究区各种类型矿床的空间分布特征进行了分析，发现斑岩型矿床明显受到构造-岩浆作用的制约，其成矿地质条件在遥感图像上能清晰、准确地解译出。故选择普拉卡约斑岩型银-多金属矿床为典型矿床，分析其地质及遥感影像特征，总结斑岩型矿床的成矿规律，并在此基础上，建立斑岩型矿床的地质-遥感找矿模型。6.对研究区内成矿地质条件及遥感找矿标志优异的地区进行成矿预测，圈定位于普拉卡约矿区正北方向约2公里处的火山穹丘为成矿预测区。更多还原

【Abstract】 Andean mineralization belt is an important part of the circum Pacificmetallogenic belt,it’s rock metallogenic epoch is in Cenozoic.The formation of thedeposit small influenced by the externa,In remote sensing image,it can clearly reflectmetallogenic geological environment of the deposit, especially in northeast region ofBolivia’s Potosi,it is obviously zonal distributed for various types of deposits,isproduced for the eastern Cordillera fold belt and Puna plateau contact belt and its bothsides.I choose to Bolivia’s Posey area of northeast as the study area,extracte remotesensing geological information and metallogenic prediction.This article summed up regional geological data of Bolivia Potosi,applicatesETM+/ASTER remote sensing data, interpretation of linear structure, ringstructure, rock and strata geological remote sensing information, and through theremote sensing image processing technology to extract the information ofmineralization and alteration. Through these geological remote sensing information,in-depth analysis of the regional porphyry deposit ore-controlling factors and remotesensing prospecting marks, focuses on the study of typical deposit geological remotesensing characteristics, induction of porphyry type deposit geological remote sensingprospecting model,prediction understanding:1.Regional remote sensing linear structure display as nearly north-south andnorth-north-west,In remote sensing image, the south-north fracture structure displaysthat it is arranged linearly for the volcano rock,is the contact zone of the volcano rockbelt and sedimentary strata,control distribution of the formation and rock,is the mainore conducting structure in the study area; NNW trending fracture displays as thelinear valley, cuts deep,move toward stability, is transpressional faults that undercompressive stress for formation as the main ore controlling structure; in the remotesensing image, north-east-east fault that it’s small size displays as dislocation of theformation.According to the fracture cutting of the fracture,it is the latly strike-slipfault.Volcano dome of the radially inner fracture of volcano dome showed"V"shape,itcut deeply valley,is the mainly ore-bearing structures.2.In study area,the circular structure is the volcano dome that formed bymagmatic activity.In remote sensing image,it show the protruding positivelandform,annular image is obviously. the pluton that it is located the center of volcano dome is acidic porphyry,it’s time for the Neogene, porphyry and the early rockstrongly alter,formed apparent mineralization and alteration zoning. radial linearstructure of peripheral rock shows,early intrusion are emplaced by advancedintrusive,causing it to rupture.These radial fissure become favorable sites ofaggregation substance.3.The study area the eastern and northwestern of the study area have lots of foldstructure,the nuclear of the syncline structure by the Neogene and Quaternary loosedeposit composition.two strata by the Silurian and early Cretaceous sandstone andsiltstone strata composition.The sedimentary deposits and stratabound deposit of thisregional is obviously controlled by fold tectonic, showed bedding distribution.4.Using the ASTER data.It extract such alteration information by the band ratioand principal component analysis:Iron oxide type alteration, mudding type alterationand propylitization alteration.the middle of the study area,it is output parts of intrusiveand volcano lava,iron oxide type alteration is very strongly, it nearly north-southdistribute like the zonal;Mud type of alteration in the Cretaceous strata of the volcanodome and the east of a study area is very strongly;Propylitization altered distributionsame as iron oxide altered, mainly distributed in the site of the volcano lava andintermediate acid intrusive rock.5.Based on linear structure,ring structure, rock and stratum analysis andalteration information extraction of In the study area,combined with distribution ofmineral resources of the regional,it analyzed the spatial distribution of various typesof ore deposits in the study area,and discoveryed that the porphyry type deposits isobviously restricted by tectonism and magmatism, in remote sensing image,themetallogenic geological conditions can clearly, accurately interpret.So I choosepulacayo porphyry silver polymetallic deposit as a typical deposit, analysis of thegeology and the characteristics of remote sensing image, summary of metallogenicregularity of porphyry type deposit,and on this basis, establishment of geological-remote sensing prospecting model of porphyry type deposit.6.It is metallogenic forecasting for superior region of metallogenetic geologicalconditions and remote sensing prospecting of the study area,delineating the volcanodome that is located in the North approximately2km from pulacayo mining area asmetallogenic prospective area.更多还原