新疆东天山玉海铜矿蚀变矿化特征及SWIR勘查应用研究
Alteration and Mineralization of the Yuhai Cu Deposit in Eastern Tianshan,Xinjiang and Applications of Short Wavelength Infra-Red (SWIR) in Exploration

玉海铜矿位于东天山大南湖-头苏泉岛弧带的东段，是新疆有色地勘局704队近年来发现的一中型铜矿床，但人们对其蚀变和矿化分布特点、矿床成因类型依然知之甚少.基于详细的矿床地质、黑云母和绢云母Ar-Ar同位素定年及短波红外光谱(SWIR)研究，结果表明矿区蚀变主要有黑云母-磁铁矿化、绢英岩化及绿泥石化.其中，黑云母-磁铁矿化在矿区石英闪长岩中均有分布；绢英岩化出现在石英闪长岩中，呈带状分布；绿泥石化在石英闪长岩中均有分布，但在黑云母-磁铁矿化与绢英岩化接触部位，绿泥石化最强.黄铜矿化主要以黄铜矿-黄铁矿-磁铁矿、绿帘石-黄铜矿组合的形式出现，前者与黑云母-磁铁矿化关系密切，后者与绢英岩化关系密切.黑云母及绢云母40Ar/39Ar定年得到的年龄为324～314 Ma，与矿区出露的花岗岩年龄(325.4±2.5Ma)在误差范围内相似，但地质条件表明矿区黑云母及绢云母Ar-Ar体系均可能被后期岩浆作用重置，结合前人研究成果，玉海铜矿化可能形成于360～350Ma.此外，矿区绿泥石Fe-OH特征峰位值(Pos2250)的高值 (＞2 253nm)主要分布在绢英岩化带及其附近，且与矿体位置相近，可作为玉海矿区找矿勘查的标志.
The Yuhai Cu deposit, recently discovered by the No.704 Geological Party of Xinjiang Geological Exploration Bureau for Nonferrous Metals, is located in the eastern part of the DananhuTousuquan island arc belt, eastern Tianshan. The alteration and mineralization features, and metallogenesis of the Yuhai deposit are still controversial. Detailed studies on ore geology, biotite and sericite ArAr isotopic dating, and short wavelength infrared (SWIR) indicate that biotitemagnetite, phyllic and chlorite alteration are well developed at Yuhai. The biotitemagnetite alteration extensively occurs in the quartz diorite, the phyllic alteration zone mainly occurs in the quartz diorite, and the chlorite alteration mainly occurs in the transitional zone of biotitemagnetite and phyllic alterations belts. Chalcopyrite mineralization occurs as chalcopyritepyritemagnetite and epidotechalcopyrite assemblages, and the former is closely related to the biotitemagnetite alteration, while the latter is associated with the phyllic alteration. The results of biotite and sericite40Ar/39Ar dating are ca. 324-314Ma, consistent with the age of Yuhai granite (325.4±2.5Ma) in errors. Integrating with local geology, biotite and sericite ArAr systems were likely reset after their formation. Combined with previous studies, the biotitemagnetite and phyllic alterations were likely formed at 360-350 Ma, related with the emplacement of the Yuhaixi gneissic granite (or other coeval intrusions). Short wavelength infrared (SWIR) research at Yuhai reveals that high values (＞2253nm) of chlorite Fe-OH absorption peak (Pos2250) mainly occur in the phyllic alteration zone and its adjacent areas, pointing to the Cu bodies, which can be used as a potential exploration tool in depositscale