【正文】 青海錫鐵山鉛鋅礦礦床成因研究 Study on genesis of Xitieshan leadzinc deposit, in Qinghai Province 摘 要 錫鐵山鉛鋅礦床產(chǎn)于青海省柴達(dá)木盆地北緣早古生代烈焰的中基性火山 沉積巖系中，發(fā)育一套完整的噴流沉積系統(tǒng)，包括管道相，近噴口相以及噴流沉積相，是我國規(guī)模最大的鉛鋅礦床之一。礦體中產(chǎn)有非層狀和層狀礦體兩類礦體，其中非層狀礦體鉛鋅礦體呈不規(guī)則狀產(chǎn)于大理巖中，是錫鐵山礦床的主要礦體類型，非層狀礦體產(chǎn)于大理巖邊部，規(guī)模較小。本文的成礦 流體初步研究表明，代表噴流管道相的網(wǎng)脈狀蝕變巖的溫度，鹽度范圍非常寬，多期次的流體活動強烈，具有噴流系統(tǒng)管道相的明顯特征。代表近噴口相的產(chǎn)于厚層狀大理巖中的非層狀鉛鋅礦體旁側(cè)的碳酸鹽中包裹體個體大，溫度高，亦有明顯的形成于未噴出海底的中 高溫?zé)嵋夯顒犹卣?。碳酸鹽（大理巖）與網(wǎng)脈狀蝕變巖有相同的 H2ONaClCO2流體類型，溫度稍低，流體從管道相流向非層狀礦體，具有繼承性。層狀礦體流體的均一溫度及冷凍溫度范圍與非層狀礦體基本相同。流體包裹體的溫度、鹽度、氣液相成分測試以及同位素組地球化學(xué)研究證明錫鐵山礦床 形成于噴流沉積系統(tǒng)。管道相成礦流體以深源為主，深源流體的CO2等氣相組分溢出及深源流體與海水的混合作用導(dǎo)致了成礦物質(zhì)沉淀。結(jié)合成礦模式認(rèn)為，礦床鉛同位素具有造山帶與上地殼混合來源的特點。顯示噴流成礦過程中鉛及成礦金屬物質(zhì)主要有噴流鹵水提供，少量物質(zhì)來源于海水。層狀礦體與非層狀礦體均屬于形成于噴流沉積過程，非層狀礦體屬未噴出海底的熱液礦體。 關(guān)鍵詞 礦床地質(zhì)特征；流體包裹體；同位素特征；噴流沉積型；錫鐵山鉛鋅礦 Abstract The Xitieshan leadzine deposit in Qinghai Province,China occurs in an Early Paleozoic sequence of intermediatebasic volcanic rocks and sediments developed in the northern margin of the Qaidam basin,It has been recognized that there is a plete exhalation sedimentary system that includes breccias pipestockwork,nonbedded andbedded ores and marble from exhalation is one of the biggest leadzine dsposits in leadzine orebody contained in marble can be divided into two types, . unstratified and bedded ones. The unstratfied orebody occurs unconformably in the main preliminary study of oreforming fluids shows that fluid inclusions is quartz form altered stockwork rocks that represent the pipe facies have a wide range of temperature and intense fluid activities are characteristics of the pipe facies of the exhalative inclusions in carbonates near the unstratified ore badies hosted in thickbedded marble which represents ventproxinmal facies are large in size and have moderate to high represent unerupted subseafloor fluid activity. Fluids in altered stockwork rocks and carbonates have similar H2ONaClCO2 system and higher temperature,both belonging to the sedimentaryexhalative fluids migrate from the pipe facies to the unstratified ore homogenization temperature and freezing temperature of sluid inclusions from stratifid ore bodies are similar with unstatified ore bodis,but lack the inclusions of great gas/liquid ratio and containing daughter minrals and CO2 ponent in fluid and the homogenization temperature is slightly lower .That is to say their fluid is deposit is evidenced an sedimentary exhalative on system by isotope geochemical study and fluid in feeders were deeply of deeplysourced gaseous ponnts such as CO2 and mixing of deelysourced fluids with seawater caused precipitation of oreforming materials. A study of Pb isotope geochemistry suggests that the first array, consisting of most of the ore samples, represents a twoponent mixing line in which the less radiogenic ponent can be identified as orogenic lead reservoir probably ing from Tianjianshan Group through the exhalation brine. The radiogenic endmember can be identified as upper crust lead reservoir probably derived from seawater. Keywords ： Geologicalfeatures。 Fluid inclusions。 Isotopic characteriestics。 Sedimentaryexhalative type。 Xitieshan lead – zinc deposit 目 錄 1 前言 .................................................................................................................................. 1 研究的目的及意義 ................................................................................................ 1 位置與交通、自然地理及經(jīng)濟狀況 .................................................................... 1 位置與交通 ..................................................................................................... 1 自然地理 及經(jīng)濟狀況 ......................................................................................... 1 以往工作評述 ....................................................................................................... 2 2 區(qū)域地質(zhì)特征 .................................................................................................................. 3 地層 ........................................................................................................................ 4 地質(zhì)構(gòu)造 ................................................................................................................ 5 構(gòu)造層劃分 ..................................................................................................... 5 褶皺構(gòu)造 ......................................................................................................... 6 斷裂構(gòu)造 ......................................................................................................... 6 巖漿活動 ................................................................................................................ 6 侵入巖 ............................................................................................................ 6 火山巖 ............................................................................................................ 6 區(qū)域地質(zhì)演化 ........................................................................................................ 7 區(qū)域物、化探特征 ................................................................................................ 8 區(qū)域航磁場特征 .............................................................................................. 8 區(qū)域布伽重力場特征 ....................................................................................... 8 區(qū)域化探特征 .................................................................................................. 8 區(qū)域礦產(chǎn)概括 ....................................................................................................... 9 3 礦區(qū)及礦床地質(zhì)、地球化學(xué)特征 .................................................................................. 9 礦區(qū)地質(zhì)特征 ........................................................................................................ 9 地層 ...........................