Age spectra of detrital zircon of the Jurassic clastic rocks of the Mino-Tanba AC belt in SW Japan: Constraints to the provenance of the mid-Mesozoic trench in East Asia

•Detrital zircon of mid-Jurassic AC sandstone in SW Japan was dated by LA-ICPMS.•Most of zircon grains range in the Jurassic, Permo-Triassic, and middle Paleozoic.•Older grains of Paleoproterozoic and Neoarchean ages were likely from N. and S. China.•Mid-Jurassic trench in SW Japan developed along the Cathaysia margin of S. China.

U–Pb ages of detrital zircon grains were determined from an upper Middle Jurassic siliceous mudstone and two lower Upper Jurassic sandstones of the Mino-Tanba belt, Southwest Japan, by Laser-ablation ICPMS. The age spectra of detrital zircon grains of the three analyzed samples show multiple age clusters: 175–198 Ma (Early Jurassic), 202–284 Ma (Permian to Triassic), 336–431 Ma (Silurian to Carboniferous), and 1691–2657 Ma (Neoarchean to Paleoproterozoic). As per the Precambrian grains, the prominent peak exists around 1800–2000 Ma in all analyzed samples. The age clusters of 175–198 Ma, 202–284 Ma, and 336–431 Ma suggest that pre-Middle Jurassic Japan has exposed older granitic batholiths. The corresponding batholiths occur in the Cathaysian part of South China block. In contrast, the absence of them in modern Japan suggests that these batholiths were totally consumed by post-Jurassic tectonic erosion. The Neoarchean to Paleoproterozoic detrital zircon grains were derived from South China, North China, or possibly both of them; nonetheless, the circumstantial geologic lines of evidence point to South China, in particular to Cathaysia, rather than North China.

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