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格兰尼特山位于落矶山成矿省的南部,是拉拉米造山运动抬升的几个前寒武基底地块的组成部分。大多数前寒武地块向北、北西倾,但是,由许多不连续的丘岭构成的格兰尼特山则呈东-西向带状展布。该带出露长约110 km,宽20 km,其面积约为2 200km~2。怀俄明州格兰尼特山的花岗岩岩石提供了美国怀俄明州Crooks Gap,Gas山和Shirley盆地铀矿床的铀源。格兰尼特山的前进热液蚀变岩石包括绢云母化-绿泥石化-钠黝帘石化花岗岩和钠长石化花岗岩和硅化-绿帘石化花岗岩。它们的全岩平均δ~(18)O值分别为7.1‰(17个样品),6.3‰(6个样品),4.7‰(26个样品)。6个绢云母化-绿泥石化-钠黝帘石化花岗岩样品的单矿物δ~(18)O值平均为石英8.9‰,长石6.4‰。3个相应的钠长石化花岗岩的石英和长石的δ~(18)O分别为8.1‰和5.6‰;而4个硅化-绿帘石化花岗岩得出的δ~(18)O平均值石英为5.6‰,长石为3.2‰。蚀变花岗岩~(18)O亏损表明,与低~(18)O的流体(可能是大气降水)的相互作用有关,该流体为后期事件从花岗岩中淋滤铀造成了先决条件。△_(石英-长石)同位素分馏显示,热液蚀变是在温度为363±50℃的条件下产生的,热液流体的δ~(18)O估计为—6.9‰,水/岩比值约为O.4。格兰尼特山的热液蚀变事件很可能对铀的迁移造成重大的影响。在深达426.7 m的钻孔剖面中发现,强烈的破碎带、低的δ~(18)O值,热液蚀变矿物组合与铀的高度富集之间有密切的关系,说明部分铀的活化是由热液蚀变事件引起的。
Located in the southern Rocky Mountain metallogenic province, the Granite Mountain is part of several Precambrian basements uplifted by the Lalami orogeny. Most Precambrian blocks are north-west and north-west-drained, but the Granit Hills, formed by many discontinuous mounds, exhibit an east-west band. The belt is about 110 km long and 20 km wide with an area of about 2 200 km ~ 2. Granite rocks in the Granite Hills of Wyoming provide uranium sources for uranium deposits in the Crooks Gap, Gas Hills and Shirley basins of Wyoming. The advancing hydrothermal alteration rocks of the Granite Mountain include sericitized-chlorite-sodium zoisite granites and albite granites and silicified-epidote granites. The average δ 18 O values of their whole rocks are 7.1 ‰ (17 samples), 6.3 ‰ (6 samples) and 4.7 ‰ (26 samples) respectively. The single δ 18 O values of 6 sericite-chlorite-sodium zoisite granites are 8.9 ‰ quartz and 6.4 ‰ feldspar. The δ ~ (18) O of quartz and feldspar of the three corresponding albite rocks are 8.1 ‰ and 5.6 ‰, respectively. The mean values of δ ~ (18) O derived from four silicified-epidote granites are 5.6 ‰, feldspar is 3.2 ‰. The alteration of granite ~ (18) O depletion indicates a correlation with low ~ (18) O fluid (possibly atmospheric precipitation) interactions that preconditioned the leaching of uranium from granite for later events. △ _ (quartz-feldspar) isotopic fractionation showed that the hydrothermal alteration was produced at a temperature of 363 ± 50 ℃. The δ 18 O of the hydrothermal fluid was estimated to be -6.9 ‰, and the water / rock ratio About O.4. The hydrothermal alteration in the Granit Hills is likely to have a significant impact on uranium migration. In the drilling section up to 426.7 m deep, it is found that there is a close relationship between strong crustal zones, low δ 18 O values, hydrothermal alteration mineral assemblages and highly enrichment of uranium, indicating that some uranium Activation is caused by hydrothermal alteration events.