(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙 410083；
3. 河南省有色金屬礦產(chǎn)探測(cè)工程技術(shù)研究中心，鄭州 450016；
4. 河南省有色金屬地質(zhì)勘查總院，鄭州 450052)
摘 要: 姚沖斑巖型鉬礦床位于東秦嶺-大別山鉬成礦帶，礦體產(chǎn)于花崗巖外接觸帶大別片麻雜巖中。礦體下部的隱伏巖體巖性主要為二長(zhǎng)花崗巖和花崗斑巖。LA-ICP-MS鋯石U-Pb定年結(jié)果表明：二長(zhǎng)花崗巖和花崗斑巖的侵位年齡分別為(139.6±2.0) Ma和(139.8±2.2) Ma，形成于晚侏羅世-早白堊世。鋯石Hf同位素分析結(jié)果表明：姚沖鉬礦區(qū)花崗巖的εHf(t)值范圍為-30~-22.8，位于地幔演化線之下，tDM2值范圍為2.21~2.60 Ga，表明其源于揚(yáng)子板塊北緣的古老地殼，其組成類似于揚(yáng)子板塊北緣TTG型巖漿巖。姚沖鉬礦床形成于晚侏羅世-早白堊世構(gòu)造體制從擠壓收縮向區(qū)域性伸展的大轉(zhuǎn)換階段，揚(yáng)子板塊拆沉作用導(dǎo)致軟流圈上涌，誘發(fā)加厚下地殼部分熔融產(chǎn)生的花崗質(zhì)巖漿，為姚沖鉬礦床成巖成礦作用提供了物質(zhì)來(lái)源。
關(guān)鍵字: 大別山；姚沖鉬礦床；LA-ICP-MS鋯石；U-Pb年齡；Hf同位素
（1. Key Laboratory of Nonferrous Metal Ore Forecast, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info physics, Central South University, Changsha 410083, China;
3. Non-Ferrous Mineral Exploration Engineering Research Center of Henan Province, Zhengzhou 450016，China;
4. Henan Institute of Geological Exploration for Non-ferrous Metal, Zhengzhou 450052, China）
Abstract:Yaochong Mo deposit is located at Qinling-Dabie metallogenic belt, the deposit is produced in Dabie metamorphic complex at the exocontact zone. Yaochong concealed stock consists of the monzogranite and granite porphyry, which yield LA-ICP-MS zircon U-Pb ages (139.6±2.0) Ma and (139.8±2.2) Ma, respectively, indicating that Yaochong granite was formed at the Late Jurassic-Early Cretaceous magmatism. According to zircon Hf isotope analyses, the εHf(t) values of the granite range from -30 to -22.8, which is located below the depleted mantle line. The tDM2 values range from 2.21 Ga to 2.60 Ga, which indicates the granite was formed from the lower crust of Yangtze Block. The component of the granite porphyry is similar to Neoproterozoic TTG magmatic rocks. The mineralization of Yaochong Mo deposit was formed in the Late Jurassic-Early Cretaceous period of the transformation of tectonic regime. The granitic magma was derived from the patial melting of ancient crust triggered by asthenosphere upwelling, which probably provides diagenesis and ore-forming material of Yaochong Mo deposit.
Key words: Northern Dabie Mountain; Yaochong Mo deposit; LA-ICP-MS zircon; U-Pb age; Hf isotope
