【摘要】：滇西北云龍白洋廠Cu-Ag礦床位于蘭坪中-新生代盆地中南段。前人少量研究工作表明,區(qū)內(nèi)Cu-Ag礦床屬滲濾熱鹵水后生層控礦床或沉積-改造礦床。但本次調(diào)查發(fā)現(xiàn),礦區(qū)內(nèi)地層、構(gòu)造等地質(zhì)條件存在誤解,且區(qū)內(nèi)獨具特點的Cu-Ag礦床成礦作用及成因機制尚未被揭示。為此,本文在對白洋廠礦區(qū)進行系統(tǒng)的地層、構(gòu)造、礦化、蝕變填圖的基礎上,查明了Cu-Ag礦床(體)的基本地質(zhì)特征,約束了其成礦時代；借助構(gòu)造-巖相蝕變填圖、巖礦相學及同位素示蹤分析,重點查明了重晶石化的發(fā)育特征及時空分布規(guī)律,建立礦床的礦化-蝕變結(jié)構(gòu)模型,分析了礦床成因。論文主要取得以下成果和認識：(1)礦區(qū)主要表現(xiàn)為以近南北向緊閉背斜、開闊向斜及與背斜伴生的正斷層組合為發(fā)育特征的同沉積坳陷帶,并發(fā)育構(gòu)造垮塌體及含石膏砂泥底劈體；主要出露上白堊統(tǒng)南新組、虎頭寺組及古-始新統(tǒng)云龍組砂泥巖均發(fā)育多層次的發(fā)育軟沉積構(gòu)造巖層；近南北向的F1斷層為主要的導流控礦同沉積斷層。(2)主要Cu-Ag礦體呈浸染狀、細(網(wǎng))脈狀賦存于虎頭寺組淺色巖屑長石石英砂巖及破碎角礫巖帶中的淺色砂巖角礫中,伴生強烈的重晶石化及弱的方解石化與石膏化。地層巖性、同沉積斷層、褶皺變形、構(gòu)造垮塌體與含石膏砂泥底劈體的有機組合,控制了區(qū)內(nèi)Cu-Ag礦床成礦流體的遷移及沉淀成礦。成礦作用過程可劃分為成巖成礦期、熱液成礦期和表生富集期。(3)從礦體中心往邊部,重晶石化的產(chǎn)出形式依次為斑點狀—細脈狀—粗脈狀,并明確了重晶石化與伴生金屬硫化物礦化、方解石化的關系。(4)礦床的硫源具多來源性,并顯示復雜的同位素分餾過程；鉛源具有明顯的殼源特點；鍶來源于沉積巖圍巖地層；成礦流體具有多來源性和混合流體特征。(5)本礦床屬于沉積坳陷帶背景下受同沉積變形構(gòu)造控制的SSC型礦床,形成于虎頭寺期晚期—云龍期早期(K2～E1-2)區(qū)域性拉張盆地向走滑拉分盆地轉(zhuǎn)化階段,是深部富集H2S排泄流體與當時湖水或盆地鹵水遷移混合的產(chǎn)物。(6)提出白洋廠礦區(qū)南部是有利的找礦靶區(qū)。其中,上白堊統(tǒng)淺色砂巖中的斑點、細脈狀重晶石及伴生的方解石、石膏等組合,是重要的找礦指示性標志。
[Abstract]:The Yunlong Baiyang Chang Cu-Ag deposit in northwest Yunnan is located in the middle and south section of Lanping Mesozoic-Cenozoic basin. A few previous studies have shown that the Cu-Ag deposits in the area belong to percolation heat brine epigenetic stratabound deposits or deposition-modified deposits. However, it is found that there are misunderstandings in geological conditions such as strata and structures in the interior of the mining area, and the metallogeny and genetic mechanism of the Cu-Ag deposit with unique characteristics in the area have not been revealed. Therefore, based on the systematic mapping of strata, structures, mineralization and alteration in Baiyangchang mining area, the basic geological characteristics of the Cu-Ag deposit (body) have been found out and its metallogenic epoch has been restricted by the help of tectonic-lithofacies alteration mapping. Based on the petrographic and isotopic tracer analysis, the developmental characteristics and space-time distribution of barite are found out, the mineralization-alteration structure model of the deposit is established, and the genesis of the deposit is analyzed. The main achievements of this paper are as follows: (1) the main features of the mining area are synsedimentary depression, which is characterized by the closed anticline, the open syncline and the normal fault association associated with the anticline. And developed structural collapse and gypsum bearing sand and mud bottom split, mainly exposed the Upper Cretaceous Nanxin formation, Hutousi formation and Paleo-Eocene Yunlong formation sand and mudstone all developed multiple layers of soft sedimentary structural strata; The F _ 1 fault near the north-south direction is the main flow-controlling ore-controlling synsedimentary fault. (2) the main Cu-Ag orebody is dyed, and the fine (net) vein occurs in the shallow-colored lithic feldspar quartz sandstone of the Hutousi formation and in the shallow-colored sandstone breccia in the broken breccia belt. Accompanied by strong barite and weak calcite and gypsum. The organic combination of stratigraphic lithology, synsedimentary faults, fold deformation, structural collapse and gypsum bearing sand and mud bottom cleavage controls the migration of ore-forming fluids and the precipitation of ore-forming fluids in Cu-Ag deposits in the region. The process of mineralization can be divided into diagenetic metallogenic stage, hydrothermal metallogenic stage and supergenetic enrichment stage. (3) from the center to the edge of the orebody, barite occurs in the order of dotted, vein-like and coarse-vein. The relationship between barite mineralization and associated metallic sulphide mineralization and calcite is also clarified. (4) the sulfur source of the deposit has multiple sources and shows complex isotopic fractionation process, lead source has obvious characteristics of crust source, strontium comes from sedimentary rock surrounding rock strata, and strontium comes from sedimentary rock and surrounding rock strata. The ore-forming fluid has the characteristics of multi-source and mixed fluid. (5) the deposit belongs to SSC type deposit controlled by synsedimentary deformation structure in the background of sedimentary depression. It was formed in the transition stage from the regional extensional basin to the strike-slip extensional basin in the late Hutousi period and the early Yunlong period (K2~E1-2). It is the product of the migration and mixing of deep enriched H 2S discharge fluid with lake water or basin brine at that time. (6) it is suggested that the southern part of Baiyangchang mining area is a favorable prospecting target area. The combination of spots, veinaceous barites and associated calcite and gypsum in the light colored sandstone of upper Cretaceous is an important indicator for prospecting.
【學位授予單位】：昆明理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.41;P618.52

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