本文關(guān)鍵詞： 林子宗群陸相火山巖 Ag-Pb-Zn礦 Si-H-O同位素 古熱泉噴口 低硫化淺成低溫?zé)嵋盒虯u-Ag礦　出處：《地質(zhì)學(xué)報》2017年04期 　論文類型：期刊論文

【摘要】：拉薩地塊南木林盆地林子宗群火山機(jī)構(gòu)內(nèi)發(fā)育有斯弄多隱爆角礫巖型、熱液脈型Ag-Pb-Zn礦床,該礦床金屬礦物為閃鋅礦、方鉛礦,少量黃銅礦和輝銀礦,蝕變礦物為絹云母、伊利石、玉髓、蒙脫石、碧玉、方解石、菱錳礦和菱鐵礦,符合低硫型淺成低溫?zé)嵋旱V床的基本特征。本次研究對陸相火山巖中熱泉噴口的硅質(zhì)條帶及穿切礦體石英脈進(jìn)行了Si、H、O同位素測試,結(jié)果表明:(1)硅質(zhì)條帶的石英單礦物δ~(30)Si_(NBS-28)為-1.2‰~-0.4‰,記錄有熱水沉積Si同位素地球化學(xué)特征,為古熱泉硅華成因;(2)受后期火山熱液作用改造的熱水沉積硅質(zhì)條帶全巖δ~(30)Si_(NBS-28)為-0.2‰~+0.3‰,顯示火山巖與熱水沉積巖混合特征;(3)穿切礦體石英脈δ~(30) Si_(NBS-28)值為-0.8‰~-0.1‰,與熱水沉積硅質(zhì)條帶石英單礦物Si同位素組成一致,顯示低溫成因高Δ30Si同位素分餾值特征;(4)石英脈和硅質(zhì)條帶全巖的流體包裹體氫氧同位素特征顯示大氣水與火山巖發(fā)生了水-巖交換作用的"氧同位素漂移"現(xiàn)象,說明成礦流體在火山巖地層中經(jīng)歷了長期的循環(huán)作用。因此,Si-H-O穩(wěn)定同位素指示:礦區(qū)內(nèi)仍保留有古熱泉噴口,表明礦區(qū)自古新世火山巖噴發(fā)和成礦后,剝蝕程度低,"缺位"尋找低硫化淺成低溫?zé)嵋盒虯u-Ag礦床的勘查潛力較大,低δ~(30)Si_(NBS-28)值石英脈和硅化是重要找礦標(biāo)志。
[Abstract]:In the volcanic mechanism of Linzizong Group in the South Mulin Basin of Lhasa block, there are Ag-Pb-Zn deposits of the Srundo cryptoexplosive breccia type and hydrothermal vein type. The metallic minerals of the deposit are sphalerite, galena, a small amount of chalcopyrite and pyroxene, and the altered minerals are sericite. Illite, chalcedony, montmorillonite, Jasper, calcite, rhodochrosite and siderite, In accordance with the basic characteristics of low-sulfur type epithermal hydrothermal deposits, the siliceous bands of hot spring vents in continental volcanic rocks and the quartz veins of penetrating orebodies have been measured by Si-H _ 2O isotopic measurements. The results show that the quartz monomineral 未 ~ (30) S _ (S _ (28)) of the siliceous belt is -1.2 鈥，

本文編號：1497829