本文選題：沃溪金銻鎢礦床 + 流體包裹體　； 參考：《成都理工大學(xué)》2017年碩士論文

【摘要】：沃溪金銻鎢礦床地處湘西,位于雪峰構(gòu)造帶轉(zhuǎn)折部位。該礦床產(chǎn)于晚元古界板溪群馬底驛組濁積巖地層之中,受地層與構(gòu)造控制明顯,以金、銻、鎢均達(dá)到工業(yè)品位而聞名于世,是我國著名的大型金銻鎢礦床。礦體分為似層狀礦體及脈狀礦體,主要礦石礦物為自然金、輝銻礦和白鎢礦,圍巖蝕變類型主要有褪色化、黃鐵礦化以及硅化。本文在前人研究的基礎(chǔ)上,采用流體包裹體的研究方法對成礦流體進(jìn)行研究,采集不同期次不同階段的石英、白鎢礦和方解石樣品,進(jìn)行室內(nèi)觀察、描述、測試以及計(jì)算,得出如下結(jié)論:流體包裹體主要包括H_2O包裹體和CO_2-H_2O包裹體兩類,以H_2O包裹體為主。成礦作用包含四個(gè)階段,第一階段均一溫度變化范圍為117~185℃,平均157.6℃,成礦溫度介于173~214℃,鹽度介于3.85~6.52wt%Na Cl,平均5.25wt%Na Cl,pH值5.74,呈現(xiàn)出弱堿性,Eh值-0.0578,表現(xiàn)出弱還原性,f_(O2)值為10~(-50.84),f_(CO2)值為3.202,f_(S2)值為10~(-13.35);第二階段均一溫度變化范圍為120~182℃,平均157.5℃,成礦溫度介于185~210℃,鹽度介于1.24~7.14wt%Na Cl,平均4.95wt%Na Cl,pH值5.73,呈現(xiàn)出弱堿性,Eh值-0.0775,表現(xiàn)出弱還原性,f _(O2)值為10~(-50.66),f_(CO2)值為2.687,f_(S2)值為10~(-13.36);第三階段均一溫度變化范圍為125~170℃,平均150.0℃,成礦溫度介于183~201℃,鹽度介于3.53~6.17 wt%Na Cl,平均4.66wt%Na Cl,pH值5.73,呈現(xiàn)出弱堿性,Eh值-0.0596,表現(xiàn)出弱還原性,f_(O2)值為10~(-51.47),f_(CO2)值為3.521,f_(S2)值為10~(-13.55);第四階段均一溫度變化范圍為95~153℃,平均132.6℃,成礦溫度介于162~186℃,pH值5.73,呈現(xiàn)出弱堿性,Eh值-0.073,表現(xiàn)出弱還原性,f_(O2)值為10~(-54.23),f_(CO2)值為3.609,f _(S2)值為10~(-14.05)。通過CO_2-H_2O包裹體測得成礦壓力值介與293.1~505.8 bar,平均391.6 bar,對應(yīng)成礦深度為1.11~1.91km。成礦流體密度值介于0.936-0.982g/cm~3,各成礦階段密度無明顯變化。同位素證據(jù)表明,礦質(zhì)來源于殼源,介質(zhì)水來源于變質(zhì)水與大氣降水的相互混合。金主要以Au(HS)_2~-的形式進(jìn)行遷移,銻主要以硫絡(luò)合物HSb_2S_4~-的形式遷移,鎢主要以WO_4~(2-)和HWO_4~-的形式進(jìn)行遷移,金、銻、鎢沉淀的機(jī)制是溫度的降低,除此之外,鎢的沉淀還受第一階段pH值降低的影響,且溫度的降低可能與多種因素有關(guān)。
[Abstract]:Woxi gold-antimony-tungsten deposit is located in western Hunan, located at the turning point of Xuefeng structural belt. The deposit occurs in the late Proterozoic turbidite strata of the Madiyi formation of Banxi Group in the late Proterozoic and is obviously controlled by strata and structures. It is well known for its industrial grade of gold, antimony and tungsten, and is a famous large gold-antimony-tungsten deposit in China. The ore body is divided into stratiform ore body and vein ore body, the main ore minerals are natural gold, stibnite and scheelite, and the alteration types of surrounding rock are mainly fading, pyrite and silicification. On the basis of previous studies, the fluid inclusions are used to study the ore-forming fluids. Samples of quartz, scheelite and calcite at different stages are collected for laboratory observation, description, testing and calculation. The main conclusions are as follows: the fluid inclusions mainly consist of two types: s / H _ 2O inclusions and CO_2-H_2O inclusions, with H _ 2O inclusions as the main inclusions. The metallogenic process consists of four stages. In the first stage, the homogenization temperature ranges from 117 to 185 鈩，

本文編號：1859641