地质学报2025，Vol.99Issue(6)：1928-1946,19.DOI:10.19762/j.cnki.dizhixuebao.2025142
华北克拉通乌拉山地区新太古代晚期—古元古代早期石榴子石花岗岩的成因及地质意义
Late Neoarchean-early Paleoproterozoic garnet granites from the Wulashan area,North China Craton:Genesis and geological significance
摘要
Abstract
Wulashan is located in the middle section of the Khondalite Belt,western North China Craton,with well-developed supracrustal rocks mainly composed of garnet-biotite gneiss.They underwent strong metamorphism,deformation and anateixs,resulting in the formation of garnet granite.This study conducted field geological,geochemical,and zircon SHRIMP U-Pb geochronological studies on the garnet granite.There are often transitional relationships between garnet-biotite gneiss,anatectic garnet-biotite gneiss and garnet granite,with the garnet granite exhibiting in situ to semi in situ properties.Four garnet granite samples have the metamorphic-anatectic zircon ages of 2463～2442 Ma.Considering the strong overprinting of late Paleoproterozoic tectonothermal event,it is reasonable to tentatively set the formation age of garnet granite between 2.45 and 2.5 Ga or closer to 2.5 Ga.This supports the conclusion that garnet-biotite gneiss formed in the late Neoarchean.The garnet granite shows large variations in elemental composition,with SiO2,TFeO+MgO,Na2O,and K2O contents of 66.41％～73.79％,0.22％～5.59％,2.96％～5.27％,and 1.54％～5.27％,respectively.TREE,(La/Yb)N,and Eu/Eu*are 83.45×10-6～262.44 × 10-6,11.2～182.6 and 1.15～3.62,respectively.They have whole rock εNd(t)of-0.18 to 1.65 and tDM2(Nd)of 2.77 to 2.60 Ga,while metamorphic-anatectic zircons have εH((t)of-0.86 to 4.54 and tDM2(Hf)of 3.04～2.69 Ga.The significant variation of garnet granite in elemental composition largely reflect the differences in the composition of their source regions and the garnet differentiation degree during their formation process.The source rocks are late Neoarchean meta-clastic sedimentary rocks with different maturity(mainly garnet-biotite gneiss).The formation of the garnet granite marks a transition of the tectonic regime from compression to extension in the late Neoarchean to the early Paleoproterozoic,as well as the initial stabilization of the metamorphic basement.关键词
石榴子石花岗岩/乌拉山/SHRIMP U-Pb锆石定年/地球化学/新太古代晚期—古元古代早期Key words
garnet granite/Wulashan area/zircon SHRIMP U-Pb dating/geochemistry/late Neoarchean-early Paleoproterozoic引用本文复制引用
黄道袤,柯珊,李鹏川,董春艳,李曙光,万渝生..华北克拉通乌拉山地区新太古代晚期—古元古代早期石榴子石花岗岩的成因及地质意义[J].地质学报,2025,99(6):1928-1946,19.基金项目
本文为国家自然科学基金项目(编号 42372236)和中国地质调查局项目(编号 DD20221645)联合资助的成果. （编号 42372236）
