【摘要】：架底金礦位于揚子準地臺西南緣與華南褶皺帶接合部位的蓮花山背斜南東翼北東向強構(gòu)造變形區(qū),是貴州省地質(zhì)礦產(chǎn)勘查開發(fā)局一○五地質(zhì)大隊在貴州西部峨眉山玄武巖分布區(qū)繼大麥地金礦之后新發(fā)現(xiàn)的又一個中型原生金礦床。本文在前人研究基礎(chǔ)上,采用光薄片鏡下鑒定、X射線熒光光譜、ICP-MS和Linkam THMSG600型冷-熱臺分別對架底金礦的礦床地質(zhì)、元素地球化學特征和流體包裹體地球化學特征等進行研究,并與區(qū)內(nèi)典型的水銀洞金礦進行對比,探討區(qū)域成礦模式及找礦前景,對區(qū)內(nèi)原生型金礦找礦預測具有重要意義。通過研究取得了如下主要成果:(1)金礦體產(chǎn)出于茅口組與峨眉山玄武巖組之間的構(gòu)造蝕變體(SBT)和峨眉山玄武巖組第二段火山碎屑巖中,容礦巖石主要為凝灰?guī)r、玄武質(zhì)凝灰?guī)r和玄武質(zhì)火山角礫巖。礦體呈似層狀、透鏡狀,其形態(tài)簡單—中等,礦體平均品位為3.17×10-6。(2)礦石結(jié)構(gòu)主要有碎裂結(jié)構(gòu)、半自形—它形結(jié)構(gòu)和交代結(jié)構(gòu)等;礦石構(gòu)造主要有浸染狀、塊狀、條帶狀和細脈狀等。圍巖蝕變主要以硅化、黃鐵礦化為主,另有少量毒砂化、粘土化。(3)常量元素地球化學特征研究表明,該金礦石的常量元素地球化學特征與峨眉山玄武巖相似,可能與其容礦巖石為峨眉山玄武巖有關(guān)。(4)微量元素地球化學特征顯示,礦石中Au、As、Sb、Hg、Tl相對圍巖異常富集,反映Au、As、Sb、Hg、Tl為熱液作用所帶入。(5)稀土元素地球化學特征顯示,礦石與圍巖的REE含量和特征參數(shù)存在一定差異,但其球粒隕石標準化曲線則相當吻合,總體表現(xiàn)出負Ce異常、無明顯Eu異常,富輕稀土、貧重稀土、配分曲線平緩右傾的特征,可能說明成礦流體尚未能導致巖石的稀土元素發(fā)生變化。(6)流體包裹體地球化學研究顯示,成礦流體的均一溫度范圍為193~227℃,平均值為211℃、鹽度變化為4.03~8.28wt%NaCl,平均值為6.3wt%NaC1、密度變化為0.87~0.92 g/cm3,平均值為0.9g/cm3,具中-低溫度、低鹽度和中等密度的特點。初步顯示架底金礦具中-低溫熱液成礦的特征。(7)對比研究發(fā)現(xiàn),架底金礦地質(zhì)特征、地球化學特征與水銀洞卡林型金礦相似,說明架底金礦與水銀洞卡林型金礦可能具有相似的礦床成因,同屬于一個成礦體系。綜上所述,架底金礦受有利的巖性組合、背斜構(gòu)造和構(gòu)造蝕變體(SBT)所控制,與水銀洞卡林型金礦具有相同的成礦模式,可能顯示貴州西部峨眉山玄武巖區(qū)具有巨大的找礦前景。
[Abstract]:The Jaidi gold deposit is located in the strong tectonic deformation area of the south east wing of the Lianhuashan anticline at the junction between the southwestern margin of the Yangtze quasi platform and the South China fold belt. It is a new medium primary gold deposit discovered by the 105th geological team of Guizhou Provincial Geological Exploration and Development Bureau in the basalt distribution area of Emeishan, west of Guizhou Province, after the barley gold deposit. On the basis of previous studies, ICP-MS and Linkam THMSG600 type cold-hot platform were used to identify the deposit geology, elemental geochemical characteristics and fluid inclusion geochemical characteristics of Gedi gold deposit, respectively. Compared with the typical Shuiyindong gold deposit in this area, the regional metallogenic model and prospecting prospect are discussed, which is of great significance for the prospecting and prediction of the primary gold deposits in the region. The main results are as follows: (1) among the structural alteration (SBT) and the second member of the Emeishan basalt formation, the host rocks are mainly tuff, which occurred between the Maokou formation and the Emeishan basalt formation. Black Tortoise tuff and Black Tortoise volcanic breccia. The ore body is layered, lenticular, simple to medium in shape, with an average grade of 3.17 脳 10 ~ (-6). (2) the ore structure mainly consists of cataclastic structure, hemiform-isomorphic structure and metasomatic structure, and the ore structures are mainly disseminated and massive. Stripes and veins, etc. The main alteration of the surrounding rock is silicification, pyritization, and there are a little arsenopyrite and clay. (3) the geochemical characteristics of the major elements of the gold ore are similar to those of the Emeishan basalt. It may be related to the ore-bearing rock is Emeishan basalt. (4) the geochemical characteristics of trace elements show that the ore is abnormally enriched in relation to the surrounding rock, which indicates that the Au-As-SbSbSbHgTl is brought into the ore by hydrothermal process. (5) the geochemical characteristics of rare earth elements show that, There are some differences in REE content and characteristic parameters between ore and surrounding rock, but the normalized curve of chondrites is quite consistent, showing negative ce anomaly, no obvious EU anomaly, rich in light rare earth, poor in heavy rare earth, and the distribution curve is gently right tilting. It may indicate that the ore-forming fluid has not been able to cause the change of rare earth elements in rocks. (6) the geochemical study of fluid inclusions shows that the homogenization temperature range of ore-forming fluid is in the range of 1931 ~ 227 鈩，

本文編號：2145086