【作者】 刘伟；

【导师】 戴塔根；

【作者基本信息】 中南大学 ， 国土资源信息工程， 2007， 博士

【摘要】 论文以地洼学说成矿学理论为指导，从石湖金矿区域成矿地质背景分析入手，应用岩石学、构造地质学、矿床学、同位素地球化学、矿床地球化学等多学科知识对石湖金矿床地质特征、矿床地球化学特征、矿床成因进行了系统和深入的研究，并在全面总结成矿规律的基础上，开展了成矿预测研究工作。首次论证了石湖金矿区经历了前地槽、地台及地洼三个大的构造发展演化阶段。前地槽主要为沉积期，构成了阜平群的原岩地层；吕梁期，区域上升成为地台；燕山期，地台活化，进入地洼阶段，区域发生大规模构造、岩浆活动，为石湖金矿床的重要形成时期。对矿床的近矿围岩、岩浆岩、以及矿石的微量元素、稀土元素地球化学特征进行了系统的研究，揭示了微量元素和稀土元素在成岩、成矿过程中所反映的地球化学行为特征，表明成矿元素金主要来源于矿源层(阜平群团泊口组)。硫、铅、碳同位素分析显示硫、铅、碳来源于地幔，矿石中石英包裹体气液相成分和氢氧同位素分析显示成矿流体为岩浆水和大气降水的混合流体。成矿物理化学特征表明矿床形成于超浅成、相对偏氧化的弱碱性中温成矿环境。运用爆裂法测温在石湖金矿进行成矿流体运移方向的研究。通过测定101-4主矿体各部位的爆裂温度、编制矿体垂直等温线图(纵投影图)，判断出石湖金矿成矿流体是自矿区南端深部流向矿区北端浅部。对成矿流体运移方向的研究，从微观上解释了石湖金矿101-4矿体向南侧伏的形成机制。将矿床成矿作用与大地构造演化阶段联系起来，详细地阐述了石湖金矿床的成矿机理，认为矿床的形成具多大地构造演化阶段，多成矿物质来源、多控矿因素、多成矿作用和多成因类型的特点，提出石湖金矿床属产于太古代中级变质岩系、受断裂破碎带控制的燕山期岩浆改造混合热液型多因复成金矿床，并建立了与之相适应的成矿模式图。通过对控矿因素分析，总结出石湖金矿区断裂破碎带赋存工业矿体的条件为：①发育于阜平群团泊口组，因团泊口组为矿区的矿源层；②具有一定的规模，沿走向一般应在1000m以上；倾向延伸应大于400m；③须经历多期次多阶段的活动，活动次数多易形成多阶段矿化叠加；④伴有石英闪长玢岩脉的侵入，岩脉的侵入使断裂破碎带成为构造薄弱带，有利于成矿流体的进入和沉淀；⑤位于岩体外接触带的放射状断裂系统中，断裂破碎带走向为NW或NNW至SN向时最有利成矿。通过编制矿体厚度、品位等值线图，发现金矿化富集部位的连线同矿体的侧伏方向一致；研究发现石英矿物爆裂法测温的α—β相转变峰的出现率在矿体中具有一定的分布规律，从矿体浅部到深部α—β相转变峰出现率由高到低变化，据此规律预测矿床180m中段以下深部还具有很好的找矿前景。通过对成矿规律的研究，以矿体的侧伏规律、成矿流体的运移方向以及矿化在空间上所表现的各种富集变化规律为主要预测依据，提出了在101矿带的深部和南部具有良好的找矿前景，并经EH-4电导率成像系统勘查，圈出了101矿带南部和沿现有矿体侧伏方向的深部两个预测靶区，找矿潜力巨大。矿山近期对南部预测区进行了坑道工程验证，在180m、220m、260m三个中段均揭露到了厚度大、品位富的工业矿体。更多还原

【Abstract】 Guided by Diwa metallogenic theory, starting from analyses ofregional metallogenic background of Shihu gold deposit, thecharacteristics of geology geochemistry and the genesis of deposit inShihu gold deposit are studied systematically and deeply by using theknowledge of petrology, structural geology, mineral deposit, isotopegeochemistry, geochemistry of mineral deposits, etc. On the basis ofsummarizing of metallogenic regularities in detail, researches ofprospecting prognosis have been done.The author, for the first time, has proved that Shihu mining area hasundergone three big developing evolution stages, ie. Pregeosyncline,platform and Diwa stages. The pregeosyncline is a main sedimentationperiod in which the protolith stratum of Fuping group was formed; duringLvliang movement period, the region was arised and platform formed;when Yanshan movement period, the platform was moved into Diwastage by activating, large-scale tectonic and magmatic activities happenedin that region, which was considered as the significant forming stage ofShihu gold deposit.The geochemical feature of the microelement and the rare earthelement of the country rock near orebody, magmatite and ore are studiedsystemactically, these reveales the geochemical action feature of themicroelement and rare earth element in the ore-forming process anddiagenetic stage, and the main ore—forming element Au is derived fromthe source bed (Tuanbokou formation of Fuping group). The data ofsulfur, lead and carbon isotopes show that sulfur, lead and carbon arederived from the mantle, the data of the compositions of gas and liquidphases in quartz inclusion and hydrogen, oxygen isotopes suggest that ore—forming fluids is a mixture of magmatic hydrothermal fluids andmeteoric water. The physical chemical features suggest that the depositemplaced in a near—surface, relative oxidized and weakly alkaline ore—forming environment.The moving direction of the ore—forming fluids is studied by means of decrepitation temperature in the Shihu gold deposit. Measure ofdecrepitation temperature and the vertical isothermal diagram of quartzinclusions at different levels in orebody 101-4 suggests that ore—formingfluids moved from south to north and from deep to shallow, whichexplains microcosmically the forming mechanism of pitch to south.Contacting the ore—forming process with the stage of geotectonicevolution, the mechanism of mineralization in Shihu gold deposit isstudied in detail. The author puts forward that the forming of the Shihugold deposit is of the characteristics of multistage geotectonic evolution,multisource ore- forming materials, multiore- controlling factors,multimineralization, multigenesis typle. Controlled by the fault belt, theShihu gold deposit is a polygenetic compound ore deposits which wasformed in the Archean mesometamorphic rock and reconstructed bymixed hydrothermal in Yanshan Epoch. And a related minerogeneticmodel has been set up.Through the analyses of ore—controlling factors, the conditions ofthe ore—beating fault belt are put forward as follows: 1) it developed inthe Tuanpokou formation of Fuping group which is the source bed of themining area; 2) it has a certain scale, which is over 1,000m along thestrike and 400m along at the dip; 3) it should undergo multistage andmultiphase movements, more movements number, easily formedmultistage mineralization pile; 4) accompanying intrusion of the quartzdiorite veins, it made that the fault belt became the structural weak zone,which is favourable for the access and precipitation of the ore fluid; 5) itis the best to mineralization when the fault belts locate in radiating faultsystem and their strike is NW—trending or NNW to SN—trending.The isogram of thickness and grade of the orebody suggests that theconnection line of the mineral concentration area is coinciding with thepitch direction of the orebody; and the appearing rate ofα—βpeak ofquartz decrepitation temperature has a distribution regulation, whichchanges from high to low with the depth of the orebody. This regulationsuggests that the deposit bellow the 180m bears a good prospectingperspective.Through the study of metallogenic regularities of the gold deposit, based mainly on the pitch regularity of the orebody, the moving directionof the ore—forming fluids and various mineral concentration regularity, itis supposed that deep and south domains of the deposit bear a goodprospecting perspective. Then two forecasting targets at the south of theorebelt 101 and depth along the pitch direction of the present orebody areoutlined integrating with the methods of EH-4 electrial conductivityimage system. Through the verfication of ore—searching by the tunnel,industrial orebody with big thickness and high grade, has been foundrecently at 180m, 220m and 260m level in the south forecasting area.更多还原