Hongliugou moyite outcropped in western Hongliugou-Lapeiquan complex belt belongs to high K cal-alkalire granites,characterized by SiO2＞69.0％, A12O3＞13.0％, (K2O+Na2O)＞7.0％, K2O/Na2O＞1, 1＜A/CNK＜1.1, enrichment of LILE and depletion of HFSE (Nb, Ta, Sr, P and Ti). The REE distribution patterns show features of low ΣREE (128.47×10-6～150.67×10-6), negative anomaly of Eu, relative enrichment of LREE, and obvious fractionation between HREE and LREE. The Nb/Ta and Zr/Hf ratios are close to ratios of the upper crust, the εH (t) values of zircon range from -7.13～-5.12, with TDM2 ages between 1786～1912Ma. These characteristics suggest that the source rock might have been derived fr-om ancient crust. Diagrams for discriminating compositions of source rocks and the feature Al2O3/TiO2＜100 imply that the rock came from partial melting of arenitic metasediments in the middleupper crust. The LA-ICP-MS in situU-Pb age is 500.3±1.2Ma for zircons characterized by oscillatory zoning and Th/U＞0.4, and hence this age can be regarded as the formation age of the moyite. Combined with regional geological characteristics, the authors consider that the formation of the rock was related to the subduction of the oceanic crust, with the tectonic setting being continental margin arc.%出露于阿尔金构造带北缘红柳沟-拉配泉混杂岩带西段的红柳沟钾长花岗岩,SiO<,269.0%,AL<,2>O<,313.0%,(K<,2>O+Na<,2>O)>7.0%,K<,2>O/Na<,2>O>1,A/CNK介于1.04～1.08之间,属高钾钙碱性系列的弱过铝质岩石.该岩石富集大离子亲石元素(LILE),亏损Nb、Ta、Sr、P、Ti等高场强元素(HFSE);ΣREE偏低(128.47x10<'-6>～150.67x10<'-6>),Eu负异常中等(δEu=0.59～0.67),LREE相对富集,轻重稀土元素分馏明显,其Nb/Ta、Zr/Hf比值接近上地壳,锆石具有负的ε<,Hf>(t)值(-7.13～-5.12),两阶段Hf模式年龄(T<,DM2>)变化范围为1786～1912Ma,反映其源区物质主要来源于古老她壳.源岩判别图解和Al<,2>O<,3>/TiO<,2><100指示其为中上地壳变质砂屑质沉积岩部分熔融的产物.LA-ICP-MS锆石U-Pb年龄为500.3Ma±1.2Ma,结合锆石CL图像具有岩浆环带特征和Th/U>0.4,推断该年龄为花岗岩的形成年龄.综合区域地质背景,认为该岩石形成于与洋壳俯冲作用有关的陆缘火山弧环境.
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