本文選題：斑巖銅鉬礦床 + 拉抗俄　； 參考：《地學(xué)前緣》2017年05期

【摘要】：西藏岡底斯成礦帶拉抗俄斑巖銅鉬礦床位于西藏特提斯構(gòu)造域拉薩地塊東段中南部。拉抗俄斑巖銅鉬礦床黑云母分為巖漿黑云母和熱液黑云母。巖漿黑云母和絹英巖化帶的熱液黑云母屬于鎂質(zhì)黑云母,鉀化帶的熱液黑云母屬于鎂質(zhì)黑云母和金云母,具有富鎂的特征,是斑巖銅多金屬礦床的一個典型特征。成礦巖體花崗閃長斑巖,屬于造山帶鈣堿性巖系,具殼幔混源的成因特點,并且其黑云母與角閃石共生。與鉀化帶和絹英巖化帶的熱液黑云母相比,巖漿黑云母具有較高的BaO和TiO2含量。與巖漿黑云母和絹英巖化帶熱液黑云母相比,鉀化帶熱液黑云母具高Si和Mg(XMg),低Fe;而絹英巖化帶的熱液黑云母又比巖漿黑云母較高M(jìn)g(XMg)。巖漿黑云母溫度為706~746℃,平均值725℃;鉀化帶熱液黑云母溫度為396~453℃,平均值422℃;絹英巖化帶熱液黑云母278~372℃,平均值331℃。拉抗俄礦床黑云母氧逸度較高,均為NNO,有利于銅鉬礦化形成;從巖漿黑云母到鉀化帶熱液黑云母氧逸度升高,有利于銅鉬成礦物質(zhì)的運移,而從鉀化帶熱液黑云母到絹英巖化帶熱液黑云母氧逸度降低,溫度和氧逸度的變化可能是銅鉬沉淀的一個原因。巖漿黑云母和絹英巖化帶熱液黑云母遵循"F-Fe avoidance"結(jié)晶化學(xué)規(guī)則,而鉀化帶熱液黑云母F與XMg不遵循"F-Fe avoidance"結(jié)晶化學(xué)規(guī)則。巖漿黑云母、鉀化帶和絹英巖化帶熱液黑云母Cl與XMg均不遵循"Mg-Cl avoidance"結(jié)晶化學(xué)規(guī)則。黑云母化學(xué)成分記錄了巖漿結(jié)晶過程中流體成分的變化。從巖漿黑云母到鉀化帶熱液黑云母,再到絹英巖化熱液黑云母,Ⅳ(F)和Ⅳ(F/Cl)逐漸減小,Ⅳ(Cl)逐漸增大。巖漿向熱液演化過程中,F和Cl含量不斷增加。巖漿-成礦熱液F和Cl的含量的變化,對成礦物質(zhì)運移和沉淀具有重要的作用。從巖漿黑云母到鉀化帶熱液黑云母,再到絹英巖化帶熱液黑云母,lg(fHF/fHCl)逐漸減小,lg(fH2O/fHCl)和lg(fH2O/fHF)逐漸增大。巖漿熔體和熱液流體存在很大差別;并且絹英巖化熱液流體與鉀化熱液流體也不同,黑云母鹵素化學(xué)也不代表一種單一的流體;絹英巖化熱液流體混合大氣水。本文研究結(jié)果顯示,黑云母化學(xué)成分可以反映巖漿的性質(zhì)和化學(xué)成分以及結(jié)晶過程中的物理化學(xué)條件。
[Abstract]:The Lakon Russian porphyry copper-molybdenum deposit in the Gangdis metallogenic belt, Tibet, is located in the central and southern part of the eastern Lhasa block in the Tethys tectonic domain, Tibet. Biotite from the copper molybdenum deposit of Lakon porphyry is divided into magmatic biotite and hydrothermal biotite. The hydrothermal biotite of magmatic biotite and sericite zone belongs to magnesia biotite, and the hydrothermal biotite of potash zone belongs to magnesia biotite and phlogopite, which is a typical feature of porphyry copper polymetallic deposit. The granodiorite porphyry belongs to calc-alkaline series of orogenic belt and has genetic characteristics of crust-mantle mixing and its biotite and hornblende are symbiotic. The magmatic biotite has higher BaO and TiO2 contents than the hydrothermal biotite in the potash zone and sericite zone. Compared with the magmatic biotite and sericite zone, the hydrothermal biotite in the potash zone is characterized by high Si and MgO XMgO and low Fe, while the hydrothermal biotite in the sericite zone is higher than that in the magmatic biotite zone. The temperature of magmatic biotite is 706 ~ 746 鈩，

本文編號：1845019