(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)與地質(zhì)環(huán)境監(jiān)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. 有色金屬礦產(chǎn)地質(zhì)調(diào)查中心，北京 100012；
4. 中國(guó)科學(xué)院廣州地球化學(xué)研究所，廣州 510640)
摘 要: 江西永平十字頭鉬礦床為欽杭成礦帶北東段上新近發(fā)現(xiàn)的一個(gè)斑巖型鉬礦床，鉬礦體主要賦存于似斑狀黑云母花崗巖體與周潭組混合巖系的外接觸帶中，受巖體和構(gòu)造控制。本文對(duì)該礦床石英-硫化物脈中的輝鉬礦進(jìn)行了Re-Os同位素測(cè)年，獲得輝鉬礦Re-Os模式年齡為(156.9±2.2) Ma ~(158.5±2.4) Ma之間，加權(quán)平均值為(158±1) Ma，等時(shí)線年齡為(158.0±2.5) Ma。十字頭鉬礦床中輝鉬礦的Re含量為65.05×10-6~150.20×10-6，指示該礦床的成礦物質(zhì)來(lái)源具有殼幔混源的屬性。對(duì)比本區(qū)成巖與成礦的年齡，并結(jié)合該礦床的地質(zhì)特征及地球化學(xué)特征，認(rèn)為本區(qū)成礦與似斑狀黑云母花崗巖有密切的親緣關(guān)系，二者屬于相同地球動(dòng)力學(xué)背景下同一地質(zhì)-構(gòu)造-巖漿事件的產(chǎn)物。結(jié)合前人對(duì)欽杭帶北東段的研究成果，認(rèn)為欽杭北東段存在172~145Ma和140~130Ma兩期鉬的成礦事件。兩期成礦事件的時(shí)限與華南地區(qū)中晚侏羅世和白堊世兩大成礦高峰期一致，它們分別是對(duì)Izanagi板塊向歐亞大陸之下低角度俯沖有關(guān)的弧后局部伸展和Izanagi俯沖板塊沿NE方向快速走滑的響應(yīng)。
關(guān)鍵字: 十字頭鉬礦床；輝鉬礦；Re-Os同位素測(cè)年；成礦年齡；成巖成礦關(guān)系；成礦動(dòng)力學(xué)背景
（1. Key Laboratory of Metallogenic Prediction of Non-ferrous Metals and Geological Environment Monitoring(Central South University), Ministry of Education, , Changsha 410083, China;
2. School of Geo-sciences and Info-physics, Central South University, Changsha 410083, China;
3. China Non-ferrous Metals Geological Survey, Beijing 100012, China;
4. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China）
Abstract:The Shizitou Mo deposit in Yongping, Jiangxi is a recently discovered important deposit in the eastern section of the Qin-Hang metallogenic belt. The Mo deposit mainly occurs in the outer contact zone between the porphyraceous biotite granite and the Zhoutan group migmatite, and is mainly controlled by the rock body and structures. Re-Os dating of molybdenite gives a model age of (156.9±2.2) Ma-(158.5±2.4) Ma, with a weighed mean age of (158±1) Ma, and gives an isochron age of (158.0±2.5) Ma. The Re content of the molybdenite is 65.05×10-6-150.20×10-6, indicating that the ore-forming materials have mantle-crust mixed features. Based on the comparison between the ore-forming age and the rock-forming age of the deposit area, and by looking into the geological features and geochemical features of the deposit, it is concluded that the ore-forming process of the area is closely linked with the porphyraceous bioite granite rock body, and that both the deposit and the rock body are products of the same geological-tectonic-magmatic event under the same dynamic background. Based on previous studies in the northeastern section of the Qinhang metallogenic belt, it is believed that two episodes of Mo ore-forming events at 172-145 Ma and 140-130 Ma have occurred in the northeastern section of the Qinhang metallogenic belt. The time of the two episodes of ore-forming events corresponds with the two ore-forming peak periods in late Jurassic and Cretaceous, in response to the back-arc partial extension associated with the low-angle subduction of the Izanagi plate beneath the Eurasia plate and the quick NE striking slipping of the Izanagi subduction plate.
Key words: Shizitou molybdenum deposit; molybdenite; Re-Os isotopic chronology; metallogenic age; metallogenic- diagenetic relationship; metallogenic dynamic setting
