【作者】 周云满；

【导师】 毛景文；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2008， 博士

【摘要】 本文通过对小水井金矿床成矿地质背景、控矿构造特征、矿床地质特征、矿床化探异常和物探异常特征、成矿流体特征及与邻区金矿床进行对比研究,总结了区域成矿规律、矿床矿化富集规律、矿床成因类型和成矿模式、找矿模型、找矿预测准则和标志,对矿床及外围找矿前景进行了预测,为勘查工作的部署提供了科学依据。小水井金矿床处于扬子准地台与唐古拉-兰坪-思茅褶皱系两个一级大地构造单元的交接部位(哀牢山变质带及红河断裂)的东侧边缘。区域上有四个成矿期,分别形成了早元古代海相火山喷发-沉积-变质铁铜矿床,中元古代—中三叠世古风化壳型铁(金)矿床,燕山期-喜马拉雅早期构造破碎带热液蚀变脉状金矿床和铅锌(银)矿床,喜马拉雅晚期沉积-热液改造砂砾岩型金矿床等四种成因类型的矿床组合。构造控矿是本区金矿床的主要特点,多级断裂构造体系控制了区域金矿带、矿田、矿床、矿体及矿石类型的分布。小水井断裂(三级)控制了小水井金矿床的产出,更次级的断层、剪切裂隙破碎带、层间破碎带控制了矿体的空间产出位置。矿床控矿构造类型为脆-韧性剪切断裂构造。断裂产状变化地段、不同方向断层交切附近、破碎带的膨大部位,是厚大透镜状矿体富集的有利空间;破碎带变窄地段,矿体变薄、尖灭,形成脉状矿体。矿体的分布标高在2045～1740m范围。矿床成因类型属于浅成条件下,由中～低温混合热液流体在韧-脆性剪切构造带中形成的构造蚀变岩型金矿。矿床成矿模式为在基底地层和周边物源区岩石含金较高的背景下,由于剪切断裂构造及岩浆活动,驱动幔源流体上升和变质热液、天水-地下水形成的热液及岩浆热液沿断裂带运移,沿途不断促使地层中金活化、迁移,在浅部次级剪切断层破碎带较宽、产状由缓变陡的过渡地段逐步富集形成矿床。初步确立了矿床找矿模型,即构造对成矿的多级系统控矿模型,构造对矿化富集规律及矿体产状、形态的控矿模型,矿化蚀变分布模型,岩体与构造对矿化叠加控矿模型,成矿作用动力学模型以及物探、化探综合找矿模型。认为地质-化探-物探-钻坑工程等多种技术方法集成是发现和探明此类矿床的有效途径。预测小水井金矿北端14线以北和南端93线以南无找矿潜力,其间的14-93线长2km,1740m标高以上范围有较好的找矿前景,资源量可达10吨以上,但1740m标高以下找矿潜力有限。预测在小水井金矿之南的苏布及以北的大坎子—官郎山等地尚可发现有一定规模的矿床(金资源量10～20吨),是进一步找矿的靶区。更多还原

【Abstract】 Based on the studies of geological setting , ore-controlling geological structures, geological characteristics of ore deposits, geochemical and geophysical anomalies, metallogenic fluid characteristics and contrasted with neighboring gold deposit, the paper summarizes regional metallogenic regulations, mineralization enrichment rules, origin types of ore deposits, a metallogenic model, a prospecting model, regulations of ore prognosis and prospecting criteria . Gold prospective areas at Xiaoshuijing district and outskirt of it have been predicted. The study results provide scientific evidences for arrangement of prospection work.Xiaoshuijing gold deposit is located to the eastern margin of the conjunction of the Yangtze platform and Lanping-Simao fold belt, i.e. the eastern margin of Ailao Mountain metamorphic belt and Honghe shear zone. Regionally, there are four metallogenic stages which resulted in, respectively, early Proterozoic marine volcanic-sedimentary-metamorphic iron-copper deposits, lateritic iron (gold) deposits with their ages ranging from middle Proterozoic to Triassic, hydrothermal vein gold deposits and lead-zinc (silver) deposits controlled by shear zones formed in the period from Yanshanian to early Himalayan, late Himalayan sedimentary sandstone and conglomerate hosted gold deposit overlapped and modified by hydrothermal fluids. The deposits in the area are characterized by the ore deposit assemblage of the four mineralisation styles.The gold deposits in the area are dominated by the structurally controlled ore deposits. The structural systems at different orders respectively control the distribution of regional gold belts, ore fields, ore deposits, ore bodies and ore types. The Xiaoshuijing fault zone (at the third order) controls Xiaoshuijing gold deposit. The suborder fault zones, shear zones, interlayer fractures control distribution of ore bodies. The ore-controlling structures belong to brittle-ductile shear zones. The places where orientation of a fault zone changes or faults crosscut each other or a fault zone gets wide are favorable locations where the thick and lenticular gold ore bodies occurred. Ore bodies often get thin or thin out, or become veins in the places where an ore-controlling fault zone obviously becomes narrow. Gold ore bodies at Xiaoshuijing gold deposit occurred at the levels from 1740m to 2045m. The deposit formed in a ductile-brittle shear zone and resulted from a mixture of mesothermal and epithermal hydrothermal fluids cycling at the shallow parts of the shear zone. The deposit is an altered fault rock type gold deposit. The strata consisting of basement and adjacent source rocks are rich in gold. The tectonic activities forced fluids from the mantle to rise upward, and forced metamorphic hydrothermal fluids, hydrothermal fluids derived from meteoric water and groundwater, and magmatic fluids to pass through the fault zone. The cycling hydrothermal fluids activated gold in the strata along the passage and forced it to migrate. Gold precipitated from the hydrothermal fluids and was enriched in the locations where a fault zone gets wide or the orientation of a fault zone changes from the gentle to the steep.A model of mineralisation controlled by structures at different orders, a model of mineralisation enrichment regulations controlled by structures, a model of shapes and orientations of ore bodies controlled by structures, a model of mineralization and alteration zoning, a model of mineralization controlled jointly by rocks and structures, a dynamic model of mineralization, a comprehensive model of applying geophysical and geochemical techniques to search for mineral resources have been outlined. It is pointed out that the integration of multiple exploration methods involving geological, geochemical and geophysical techniques, and drilling and tunneling is an efficient way to discover and prove the gold deposit of this kind.It is predicated that there is no potentiality for prospecting gold in the northern part of the prospecting line 14 and in the southern part of the prospecting line 93 at Xiaoshuijing gold district. There is a good potentiality for prospecting gold in the zone between the line 14 and the line 93. The prospective zone with its elevation above 1740m is 2 kilometers long and the potential gold resources within the zone can reach more than 10 tones of gold, whereas there is a limited potentiality for prospecting gold beneath the elevation 1740m. It is also predicated that it is sure that new gold deposits can be discovered at Subu adjacent to Xiaoshuijing gold deposit and at the zone between Dakanzi and Guanlanshan in the northern part of Xiaoshuijing gold deposit. These areas are prospective targets for further prospection.更多还原