Characterizing the Provenance Signatures and Geochemical Behaviors of Turquoise in Copper Deposits:Comparative Case Studies of Meiduk,Iran,and Tongling,China  

作　　者：Bahareh Shirdam Mingxing Yang Jia Liu Ling Liu Andy Hsitien Shen 

机构地区：[1]Gemmological Institute,China University of Geosciences,Wuhan 430074,China [2]Hubei Jewelry Engineering Technology Research Center,Wuhan 430074,China

出　　处：《宝石和宝石学杂志（中英文）》2024年第S01期71-73,共3页Journal of Gems & Gemmology

摘　　要：Turquoise, a hydrous phosphate of copper and aluminum, is highly valued for its unique colour and historical significance. The similarity in colour, quality, and pattern between turquoises from different localities may lead to confusion in determining their origins. This is particularly evident in the case of turquoises from Meiduk in Iran and Tongling in China(Fig.1).In Iran, turquoise deposits are typically associated with magmatic zones, specifically in the Meiduk mine, located 85 kilometers northwest of the Sar Cheshmeh porphyry copper deposit in Kerman Province. The deposit is hosted by Eocene volcanic rocks of andesitic-basaltic composition with porphyry-type mineralization associated with two Miocene calc-alkaline intrusive phases. Five distinct zones of the hypogene alteration include potassic, potassic-phyllic, phyllic, and propylitic zones, which are rich in magnetite. Mineralization processes include stockwork, dissemination, veinlets, and veins rich in garnet, chalcopyrite, magnetite, and anhydrite. Turquoise is found in transitional, leached, and supergene zones, primarily as fracture and seam fillers. In contrast, Chinese turquoises are more often found in sedimentary rocks, with significant exceptions in places like the Tongling mine in Anhui Province, which are hosted within magmatic rocks. The turquoise from Tongling is found in the Tongling area within the Middle-lower Yangtze Metallogenic Belt, an area characterized by complex tectonics and intense magmatic and metallogenic activities. The turquoise deposits are associated with iron-copper polymetallic mineralization within Early Cretaceous volcanic rocks.The turquoise from Meiduk exhibited a specific gravity range of 2.22 g/cm^(3)to 2.71 g/cm^(3), SWUV fluorescence from none to medium, and LWUV fluorescence from faint to strong, indicating diverse mineralogical compositions. SEM examination of turquoise from Meiduk reveals a variety of mineral morphologies. The turquoise displays closely packed arrays of elongated needle-like crystals, measuri

关 键 词：TURQUOISE copper mine origin determination Meiduk Iran Tongling China 

分 类 号：P618.41[天文地球—矿床学] P619.28[天文地球—地质学]