Correlation of Late Permian basement rocks in the eastern margin of Asian continent on the basis of the CHIME dking

根据附属独居石和锆石的CHIME定年和全岩组成的XRF分析，对比了日本列岛和亚洲大陆东缘基底岩。主要结果如下：(1)北上南地体乌苏吉努砾岩的调质碎屑显示出258 ~ 247个锆石和独居石年龄，与晚二叠世化石年龄一致。如果以这些年龄作为源花岗岩就位年龄的代表，那么源区一定发生过快速剥蚀。锡霍特-阿林地区的花岗岩类显示出250 Ma左右的CHIME独居石年龄，可能是Usuginu砾岩的碎屑来源。(2)爱知县otoowa - honguusan地区硅线石质级Ryoke副长岩中的石英脉分为变形脉和非变形脉。变形脉呈边界结构，CHIME独居石年龄为95 ~ 90 Ma。未变形的脉体与清晰的断裂面不协调，推断出86 ~ 77 Ma的独居石年龄。年龄与脉体变形模式相结合，表明该区变质岩在90 ~ 86 Ma期间由韧性变形条件向脆性变形条件隆升。(3)中国东南部花岗岩类CHIME测年结果表明，在包括黄山、武公山在内的整个内陆地区，中晚侏罗世花岗岩较为突出，而中白垩世花岗岩主要分布在沿海地区。(4)筑代泽砾岩花岗岩碎屑显示178+/-3 Ma CHIME独居石年龄。这是首次证实米诺地块侏罗系地层砾岩中存在侏罗纪花岗岩类，为米诺地块碎屑岩的中生代烃源岩提供了更清晰的线索。(5)粟山花岗片麻岩锆石年龄为1.72 Ga。长期以来，它一直被认为是侵入了G^onggi地块的paragneisses。而CHIME测年结果表明，副长岩中的独居石和锆石比松山花岗片麻岩中的要年轻得多。副长岩与浅花岗岩脉折叠在一起，形成CHIME独居石和锆石，锆石年龄约为250 Ma。这表明朝鲜半岛晚二叠世变质作用强烈。(6)东古变质岩中独居石颗粒与变质峰期矿物组合处于结构平衡，平行于变质峰期形成的强烈矿物片理。所有独居石颗粒的CHIME年龄均为110 ~ 120 Ma。根据岩石学证据，认为独居石的年龄代表了变质和变形的时间。这一结论与认为东高片麻岩形成于二叠纪-三叠纪的研究结果相反。少

Basement rocks in the Japanese Islands and the eastern margin of Asian continent were correlated on the basis of the CHIME dating of accessory monazite and zircon and the XRF analyzes of whole-rock composition. The main results are as follows.(1) Tonalitic clasts in Usuginu conglomerate of the South Kitakami terrane show 258-247 zircon and monazite ages which are are consistent with the Late Permian fossil age. If these ages are taken as representing emplacement ages of the source granitoids, rapid denudation of the source areas must have occurred. Granitoids in the Sikhote-Alin area show CHIME monazite ages of around 250 Ma, and appear to be a likely source ofclasts in the Usuginu conglomerate.(2) Quartzofeldspathic veins in the sillimanite-grade Ryoke paragneiss in the Otowa-Honguusann area, Aichi Prefecture are classified into deformed and ndeformed veins. Deformed veins show boudinage structure, and give CHIME monazite ages of 95-90 Ma. Undeformed veins are discordant with a clear- … More cut boundary, and give 86-77 Ma monazite age. The ages coupled with the deformation pattern of veins suggest that the metamorphic rocks in the area had been uplifted from the ductile deformation condition to the brittle deformation conditions during the period of 90-86 Ma.(3) CHIME dating of granitoids in southeastern China disclosed that the middle to late Jurassic granites are prominent throughout the inland area including Huangshan and Wugongshan, whereas the middle Cretaceous granites are distributed mainly in the coastal region.(4) A granite clast from the Tsukiyozawa conglomerate shows 178+/-3 Ma CHIME monazite ages. This is the first authenticated document to unveil the existence of the Jurassic granitoid from the Jurassic intraformational conglomerate in the Mino terrane, and provides a clearer clue to the Mesozoic source rock for clastic rocks of the terrane.(5) The Sosan granite gneiss shows 1.72 Ga CHIME zircon age. It has long been considered to be a intrusion emplaced into paragneisses in the G^onggi massif. The CHIME dating, however, show monazite and zircon in the paragneiss are much younger that in the Sosan granite gneiss. The paragneisses were folded together with leucogranite veins which give CHIME monazite and zircon ages of c. 250 Ma. This suggests an intense Late Permian metamorphism in Korean Peninsula.(6) Monazite grains in Higo metamorphic rocks are in textural equilibrium with the peak metamorphic mineral assemblage, and are oriented parallel to a strong mineral foliation developed during peak metamorphism. All monazite grains yield CHIME ages of 110-120 Ma. On the basis of the petrographic evidence the monazite ages are interpreted as representing the time of metamorphism and deformation. This conclusion is contrary to studies which suggest that the Higo gneiss formed during the Permian-triassic. Less