本文關(guān)鍵詞： 沱沱河地區(qū) 多才瑪?shù)V床 中低溫?zé)嵋好}型礦床 礦床成因 礦化富集規(guī)律　出處：《吉林大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：在沱沱河地區(qū),多才瑪鉛鋅礦床是近年來新發(fā)現(xiàn)的超大型礦床。據(jù)最新的報告顯示,礦體儲量已經(jīng)超過600萬噸,并且找礦潛力仍有待挖掘。但是目前礦床類型尚存爭議,礦化富集規(guī)律不明,這些因素嚴(yán)重制約了下一步的找礦工作。因此急需對該礦床進(jìn)行系統(tǒng)且全面的研究,旨在為沱沱河地區(qū)找礦突破提供新的資料。本文基于野外的實地考查,結(jié)合沱沱河地區(qū)的區(qū)域地質(zhì)背景、對多才瑪?shù)V區(qū)的地質(zhì)特征和礦體特征進(jìn)行了詳細(xì)的研究,并進(jìn)行了構(gòu)造地質(zhì)學(xué)、流體地質(zhì)學(xué)、地球化學(xué)等方面的研究,查明了礦體特征、流體特征和演化規(guī)律,礦化富集規(guī)律并確定了礦床成因。多才瑪鉛鋅礦床大地構(gòu)造分區(qū)屬于青藏高原上羌塘地塊的東北部,北部是松潘-甘孜地塊,南部是拉薩地塊,區(qū)域上NWW向的大型斷裂構(gòu)造帶主導(dǎo)著礦體的形成與展布。礦體主要賦存在九十道班組,其次是沱沱河組和五道梁組,巖性主要為碎屑灰?guī)r、泥晶灰?guī)r和粉砂巖中。礦體呈脈狀和透鏡狀產(chǎn)于北西西向的張性的構(gòu)造破碎帶內(nèi)。南北向的斷裂構(gòu)造切斷礦體,造成差異性抬升的現(xiàn)象。礦石礦物主要以方鉛礦、閃鋅礦、黃鐵礦和黃銅礦為主,脈石礦物主要以方解石、石英和重晶石為主,礦石的結(jié)構(gòu)主要是粒狀結(jié)構(gòu)、碎裂結(jié)構(gòu)和交代結(jié)構(gòu),礦石構(gòu)造主要是塊狀構(gòu)造、脈狀構(gòu)造和浸染狀構(gòu)造。礦體和賦礦圍巖的碳酸鹽化、硅化和重晶石化明顯,體現(xiàn)了中低溫?zé)嵋何g變的特征。成礦可以大致分成以下3個階段,石英-黃鐵礦階段,玉髓—重晶石—碳酸鹽—方鉛礦階段,碳酸鹽-石膏階段。流體包裹體的測溫結(jié)果顯示多才瑪?shù)V區(qū)主要以氣液兩相的鹽水溶液包裹體為主,成礦流體具有中低溫(108～423.6℃)、中低鹽度(1.2～17.1%)、中低密度(0.58g/cm3～1.03g/cm3)的特征,從早到晚溫度、壓力和鹽度逐漸降低,成礦晚期流體有大氣降水的參與,主成礦壓力范圍9.87～26.03MPa,成礦深度0.99～2.60km。碳氧同位素結(jié)果表明起源于深部的流體在上升的過程中與圍巖發(fā)生了水巖反應(yīng)。硫同位素特征表明成礦流體主要來自巖漿熱液和地層硫的細(xì)菌還原作用。鉛同位素結(jié)果表明,鉛具有混合鉛特征,以殼源鉛為主混合少量深源地幔鉛。成礦流體溫度逐漸降低,不同流體的混合以及以灰?guī)r為主的圍巖消耗掉H+使得成礦流體PH增加是成礦物質(zhì)卸載沉淀成礦的主要機(jī)制。綜合分析認(rèn)為,多才瑪鉛鋅礦床屬于中低溫?zé)嵋好}型礦床,成礦時間在40～20Ma之間,晚于區(qū)域逆沖推覆構(gòu)造的形成時間,成礦構(gòu)造背景是印度-亞洲大陸的晚碰撞階段。
[Abstract]:In Tuotuohe area, the Duocima Pb-Zn deposit is a newly discovered superlarge deposit in recent years. According to the latest report, the ore body reserves have exceeded 6 million tons, and the prospecting potential is still to be excavated. However, the type of deposit is still controversial. The regularity of mineralization and enrichment is unknown, these factors seriously restrict the next prospecting work. Therefore, it is urgent to carry out systematic and comprehensive research on the deposit, in order to provide new information for the breakthrough of prospecting in Tuotuohe area. This paper is based on field investigation in the field. Combined with the regional geological background of Tuotuo River area, the geological characteristics and orebody characteristics of Duocima mining area are studied in detail, and structural geology, fluid geology, geochemistry and other aspects are studied, and the orebody characteristics are found out. Fluid characteristics and evolution rules, mineralization and enrichment rules, and the genesis of the deposit have been determined. The tectonic zoning of the Docima Lead-Zinc deposit belongs to the northeast of the Qiangtang block on the Qinghai-Xizang Plateau, the Songpan-Ganzi block in the north and the Lhasa block to the south. The formation and distribution of orebodies are dominated by the large fault structural belts of NWW direction in the region. The orebodies mainly occur in the 90 Daban formation, followed by Tuotuohe formation and Wudaoliang formation, and the lithology is mainly clastic limestone. In mudstone and siltstone, the orebody is veined and lenticular in the extensional structural fracture zone of NW direction. The fault structure of the north and south direction cuts off the orebody, which results in the differential uplift. The ore minerals are mainly galena and sphalerite, the main ore minerals are galena and sphalerite, and the ore minerals are mainly galena and sphalerite. Pyrite and chalcopyrite are dominant, gangue minerals are mainly calcite, quartz and barite, ore structure is mainly granular structure, cataclastic structure and metasomatic structure, ore structure is mainly block structure. Vein structure and disseminated structure. Carbonation, silicification and barite formation of orebody and ore-bearing rock show the characteristics of hydrothermal alteration at middle and low temperature. Ore formation can be divided into the following three stages, quartz pyrite stage. The temperature measurement results of fluid inclusions show that the fluid inclusions are mainly composed of gas-liquid two-phase saline solution inclusions in the chalcedone-barite-carbonate-galena stage, carbonate gypsum stage, and carbonate-gypsum stage, and the temperature measurement results of fluid inclusions show that the fluid inclusions are mainly gas-liquid brine solution inclusions. The ore-forming fluid has the characteristics of moderate and low temperature (108U 423.6 鈩，

本文編號：1527721