The eastern extension of Paleozoic South China in NE Japan evidenced by detrital zircon

The South Kitakami belt is unique in exposing a thick, well-preserved Paleozoic shelf sequence in Japan in which Phanerozoic accretionary complexes dominate. Its origin with respect to continental blocks has been debated in regard of two options, i.e., as belonging to the margin of North China or South China. Present work on U–Pb detrital zircon dating has identified Neoproterozoic mineral grains from the Silurian and Carboniferous sandstones in the S. Kitakami belt, and proved the link between Paleozoic Japan and South China with dominant Proterozoic basements. South China likely extended further to the east from the mainland China.

北上南带（South Kitakami belt）是日本境内极具特殊性的地质出露带，其发育一套厚层且保存完好的古生代陆棚沉积序列（Paleozoic shelf sequence），区域主体被显生宙增生杂岩（Phanerozoic accretionary complexes）占据。关于该带与大陆地块（continental blocks）的成因归属问题，学界长期存在两种争议观点，即其可归属于华北地块或华南地块的大陆边缘。本次通过U-Pb碎屑锆石测年（U–Pb detrital zircon dating）对该带内的志留系与石炭系砂岩开展研究，从中识别出新元古代（Neoproterozoic）矿物颗粒，证实了古生代日本与以元古宙基底（Proterozoic basements）为主体的华南地块之间的成因联系。华南地块的分布范围可能曾向东延伸至中国大陆以东区域。