本文選題：矽卡巖　切入點：礦物學　出處：《巖石學報》2017年07期

【摘要】：義敦地體位于三江特提斯成礦域中北段,晚三疊世和晚白堊世斑巖-矽卡巖型Mo-Cu多金屬成礦作用強烈。銅廠溝Mo-Cu礦床位于義敦地體最南端,是近年來該區(qū)新探明的Mo-Cu礦床之一,已探明資源量142.5Mt。矽卡巖在銅廠溝礦區(qū)廣泛出露,是該礦區(qū)最主要的賦礦巖石。根據(jù)礦物組合及共生關(guān)系,可將矽卡巖劃分為石榴子石矽卡巖、透輝石矽卡巖和透閃石矽卡巖三種類型。通過詳細的地質(zhì)填圖和鉆孔巖心編錄,發(fā)現(xiàn)銅廠溝礦區(qū)矽卡巖礦物組合受花崗閃長斑巖體與大理巖空間分布的控制:(1)由大理巖向外依次發(fā)育透輝石矽卡巖→透閃石矽卡巖→石榴子石矽卡巖;(2)由淺至深,石榴子石粒度逐漸變大;③礦化與透閃石、綠簾石等退化蝕變礦物密切相關(guān),礦體多形成于外接觸帶。矽卡巖中最主要的礦物是石榴子石,多呈自形粒狀或粒狀集合體產(chǎn)出,顏色較深,均質(zhì)性,以鈣鋁榴石為主(62.2%~78.3%),其次為鈣鐵榴石(16.7%~34.2%),少量錳鋁榴石、鐵鋁榴石和鎂鋁榴石,屬于鈣鋁榴石-鈣鐵榴石固溶體系列(Gro62-78And17-34Spe+Pyr+Alm2-6)。石榴子石Fe~(2+)/Fe~(3+)比值變化范圍為0.00~0.20,平均值為0.06,指示石榴子石形成于酸性的氧化環(huán)境。石榴子石的δ~(18)OSMOW變化范圍為5.2‰~9.5‰,反映矽卡巖可能直接繼承斑巖體的氧同位素組成;金屬硫化物具有較為均一的S-Pb同位素范圍(δ~(34)S(CDT)=-0.7‰~1.4‰;~(206)Pb/~(204)Pb=18.332~18.694,~(208)Pb/~(204)Pb=38.454~39.088,~(207)Pb/~(204)Pb=15.588~15.663),表明成礦流體和成礦物質(zhì)均來源于殼源的長英質(zhì)巖漿。
[Abstract]:The Yidun terrane is located in the northern section of the Tethys metallogenic domain of Sanjiang, and the late Triassic and late Cretaceous porphyry skarn type Mo-Cu polymetallic mineralization is strong. The Tongchanggou Mo-Cu deposit is located at the southernmost tip of the Yidong terrane, and is one of the newly proved Mo-Cu deposits in the area in recent years. Skarn is widely exposed in Tongchanggou mining area and is the main ore-bearing rock. According to mineral assemblage and symbiotic relationship, skarn can be divided into garnet skarn. Three types of diopside skarn and tremolite skarn. Detailed geological mapping and drilling core cataloguing, It is found that the skarn mineral assemblage in Tongchanggou mining area is controlled by the spatial distribution of granodiorite and marble. The diopside skarn is developed from marble to outside in turn. 鈫扵remolite skarn. 鈫扚rom shallow to deep, the granularity of pomegranate is gradually larger. The mineralization is closely related to the degenerative alteration minerals such as tremolite and verdite, and the orebodies are mostly formed in the external contact zone. The most important mineral in skarn is pomegranate. Most of them are self-shaped granular or granular aggregates, with dark color and homogeneity, mainly calcium and aluminum garnet 62.2 and 78.3%, followed by calcium iron garnet 16.734. 2, a small amount of manganese and aluminum garnet, iron and aluminium garnet and magnesium aluminum garnet. It belongs to the series of calcium allogite and calcium iron garnet solid solution series Gro62-78 And17-34Spe Pyr Pyr Alm2-6. The ratio of pomegranate Fe~(2 / Feanzhu3) varies in the range of 0.000. 20 and the average value is 0. 06, indicating that the pomegranate is formed in an acidic oxidation environment. The 未 18 OSMOW of the pomegranate varies from 5.2 鈥，

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