【摘要】：偏巖子金礦床是康定金礦田的主要礦床之一,康定金礦田為丹巴-康定金礦帶重要的組成部分。震旦系上統(tǒng)燈影組中段一亞段第二層中部為礦體的產(chǎn)出層位,塊層狀的富藻白云巖為賦礦巖石。含金礦脈呈近南北向成帶狀分布。氟鎂石為主要的載金礦物之一,尤其是粒狀氟鎂石。金屬礦物主要有黃鐵礦、方鉛礦、砷硫銻鉛礦、車輪礦、黝銅礦等;非金屬礦物主要為石英、氟鎂石、白云石、絹云母、螢石、方解石等。礦石的結(jié)構(gòu)主要有結(jié)晶結(jié)構(gòu)、交代結(jié)構(gòu)等。礦石構(gòu)造主要有浸染狀構(gòu)造、脈狀構(gòu)造、晶簇狀構(gòu)造、晶洞狀構(gòu)造、梳狀構(gòu)造等。蝕變類型主要為黃鐵礦化、硅化、絹云母化、碳酸鹽化、鈉長(zhǎng)石化、綠泥石化。成礦過(guò)程分為金-黃鐵礦-石英階段(I);金-氟鎂石階段(Ⅱ);金-硫化物-氟鎂石-石英階段(Ⅲ);黃鐵礦-白云石-石英階段(Ⅳ),其中Ⅱ、Ⅲ階段為主成礦階段。通過(guò)對(duì)包裹體巖相學(xué)特征觀察、溫度測(cè)定、成分分析、熱力學(xué)計(jì)算等,研究成礦流體特征。本礦床流體包裹體類型主要為H_2O溶液包裹體、CO_2包裹體、CO_2-H_2O包裹體,含石鹽包裹體,流體包裹體組合顯示了流體不混溶的特征。含石鹽包裹體僅在第I階段分布,第Ⅱ、Ⅲ階段幾乎全為CO_2-H_2O包裹體、CO_2包裹體。流體包裹體的均一溫度范圍為147.0~400℃,鹽度范圍為0.43~36.4wt%NaCl。從Ⅰ到Ⅳ階段,包裹體的均一溫度、鹽度、壓力、pH值由高到低的趨勢(shì)演化,而氧化性有所增強(qiáng)。富CO_2相CO_2-H_2O包裹體的均一溫度、完全均一壓力范圍分別為218.6~342.3℃、98.6~132.6MPa;富H_2O相CO_2-H_2O包裹體的均一溫度、完全均一壓力范圍分別為216.4~315.8℃、107.6~214.7MPa,兩種類型CO_2-H_2O包裹體的溫壓基本一致,說(shuō)明它們是同時(shí)期捕獲的CO_2-H_2O不混溶流體包裹體組合。地幔流體沿著郭達(dá)山斷裂和偏巖子斷裂等導(dǎo)礦斷裂向上運(yùn)移,當(dāng)它進(jìn)入次級(jí)斷裂、層間破碎帶等容礦構(gòu)造時(shí),由于壓力的驟然降低,致使CO_2在成礦溶液中的溶解度降低,流體發(fā)生不混溶作用。流體不混溶作用導(dǎo)致CO_2逸度降低、pH升高,致使金的硫氫絡(luò)合物溶解度降低在成礦流體中快速沉淀成礦。
[Abstract]:Metamorphic gold deposit is one of the main deposits in Kangding gold ore field, and Kangding gold ore field is an important part of Danba-Kangding gold deposit belt. The middle part of the second layer of the first submember of the Dengying formation of the Upper Upper Series of Sinian is the producing horizon of the orebody, and the algae-rich dolomite of the block layer is the ore-bearing rock. The gold-bearing veins are distributed in the near-north-south direction. Fluorite is one of the main gold-bearing minerals, especially granular magnesium fluoride. Metallic minerals are mainly pyrite galena arsenic antimony lead wheel ore tetrahedrite etc. Non-metallic minerals are mainly quartz fluorite dolomite sericite fluorite calcite and so on. The structure of ore mainly includes crystal structure, metasomatic structure and so on. Ore structure mainly includes disseminated structure, vein structure, cluster structure, crystal cavity structure, comb structure and so on. The alteration types are mainly pyrite silicification sericite carbonization albite and green-mud fossilization. The ore-forming process can be divided into (I); gold-fluoromagnesite stage (鈪，

本文編號(hào)：2181997