引用本文：段超,毛景文,谢桂青,陈志宽,马国玺,王志敏,陈焘,李伟.2016.太行山北段木吉村髫髻山组安山岩锆石U Pb年龄和Hf同位素特征及其对区域成岩成矿规律的指示[J].地质学报,90(2):250-266. DUAN Chao,MAO Jingwen,XIE Guiqing,CHEN Zhikuan,MA Guox,WANG Zhimin,CHEN Tao,LI Wei.2016.Zircon U Pb Geochronological and Hf Isotope Study on Tiaojishan Volcanic Formation, Mujicun, North Taihang Mountain and Implications for Regional Metallogeny and Magmatism[J].Acta Geologica Sinica,90(2):250-266.
中文摘要:太行山北段是中国东部中生代重要的成矿区带，髫髻山组火山岩记录了该地区中生代大规模成岩成矿事件发生的时代和有关岩浆作用源区的信息。髫髻山组安山岩中锆石大多具有明显的核幔结构， LA MC ICP MS测试得出，锆石幔部年龄为144~145Ma左右，核部年龄为208~265Ga。两组锆石年龄中，前者代表了髫髻山组火山岩的形成时代，两件样品加权平均年龄分别为14528±044Ma和14461±076Ma；后者年龄与华北克拉通在前寒武纪增生变质等演化时代一致，揭示出火山岩形成过程中华北克拉通古老地壳的参与。对应两组年龄，锆石Hf同位素特征也明显的分为两组，中生代εHf
Abstract:The North Taihangshan Mountain area is one of the most important metallogenic belts in the East China. In this area, the Tiaojishan volcanic formation recorded the metallogenic magmatism event times and resources in Mesozoic. The majority zircons from the andesite show the core mantle texture. By LA MC ICP MS U Pb geochronology dating on the core and mantle of zircons, two group ages have been gained. One is younger, with two weighted average ages as 14528±044Ma and 14461±
076Ma from two samples, which indicates the andesite forming time, and the other one is 208~
265Ga from the core of zircons, which indicates the old crustal material being in the magma forming. LA MC ICP MS in situ Hf isotopic analysis of zircons gains two different εHf(t) values ranges corresponded to the two group U Pb ages. For the younger group (~145Ma), the εHf(t) values are in the range of -25 to -10, which suggests the volcanic rocks originated from the interaction process (mixing or mingling) between the enrich mantle and the old crust; for the other group (208~265Ga), the εHf(t) values are in the range of 0 to 10, which indicate the core of zircon derived from juvenile crusts same with the major crustal growth of the North China Craton (NCC), and suggests the old crust material have been involved during this magmatism. Combined with the geochemistry studies, the Tiaojishan volcanic rocks might originate from partial melting of an enriched mantle, contaminated by the old NCC crustal component en route, then emplaced after fractional crystallization. This volcanic event was formed in Mesozoic metallogenic magmatism event, and it implicates the NCC tectonic changing by lithosphere extension in Late Mesozoic. Based on the geochronology data, we infer that there might be two major metallogenic events, one is characterized by the forming of porphyry Cu Mo deposits, and the other one is characterized by the forming of Au deposits.