【摘要】 辽吉硼矿带是世界级非金属成矿省,但其成矿时代研究薄弱,成因类型和构造环境认识分歧。本文报道新获得的后仙峪超大型硼镁矿床金云母⁴⁰Ar-³⁹Ar年龄,并厘定成矿时代。主矿体金云母氩-氩坪年龄为884.4±8.9Ma（MSWD=0.47）,正、反等时线年龄分别为885.0±7.5 Ma（MSWD=0.55）和885.8±7.3 Ma（MSWD=0.79）,表明主成矿事件发生在885Ma左右,可能与Rodinia超大陆汇聚事件有关。矿体与闪长岩脉接触带蚀变岩的金云母氩-氩坪年龄为386.5±3.9Ma（MSWD=1.4）,正、反等时线年龄分别为386.7±5.3 Ma（MSWD=2.6）和387.1±7.2 Ma（MSWD=3.9）,代表成矿后局部改造事件的年龄,后期改造与早泥盆世岩浆作用有关。更多还原

【Abstract】 The Liao-Ji giant boron belt is a world-class non-metallic ore province,but its metallogenic time has not been well constrained yet.The metallogenic type and tectonic setting of the Liao-Ji boron belt are still controversial.In this paper we present new ⁴⁰ Ar-³⁹ Ar phlogopite ages for the Houxianyu Boron deposit to time the boron mineralization.Phlogopite grains separated from the major ore-body yield ⁴⁰ Ar/³⁹ Ar plateau age of 884.4±8.9Ma（MSWD=0.47）,isochron age of 885.0±7.5Ma（MSWD=0.55） and antiisochron age of 885.8±7.3Ma（MSWD=0.79）,respectively.This shows that the boron mineralization mainly occurred at ca 885 Ma and might be genetically related to the assembly of the Rodinia supercontinent.Whilst the phlogopite grains separated from contact-zone metasomatite between ore-body and diorite dyke yield ⁴⁰ Ar/³⁹ Ar plateau age of 386.5±3.9 Ma（MSWD=1.4）,isochron age of 386.7±5.3 Ma（MSWD=2.6） and anti-isochron age of 387.1±7.2 Ma（MSWD=3.9）,respectively,reflecting a post-ore overprint event which was possibly related to the Early Devonian magmatism.更多还原