Provenance analysis based on detrital zircon U−Pb ages from the Sanbagawa Metamorphic Rocks in eastern Kii Peninsula

<p> Introduction: Detrital zircon U−Pb dating is not available only to constrain depositional age, but also to infer its provenance. However, provenance has not been discussed in these previous studies. In this study, provenance analysis for the Sanbagawa Metamorphic Rocks in the eastern Kii Peninsula based on detrital zircon U–Pb dating was carried out.Analytical methods and Result: U–Pb dating of detrital zircons from psammitic rocks of the Sanbagawa Belt in eastern Kii Peninsula, Japan was carried out. Tectonic unit was divided based on lithology and the YZ (youngest age of single grain) and YC1σ (weighted mean age of the youngest cluster). Four sedimentary types are distinguished according to zircon age proportions: Cretaceous type, Permain–Jurassic type, Precambrian type and mixed type. Combining age data with geological characteristics of the area and compare with previous studies (Jia and Takeuchi, 2020), we divide into four complexes: Kayumi Complex (Cretaceous and mixed types), Haze Complex (Precambrian type), Hachisu Complex (Cretaceous and mixed types) and Mayoidake Complex (Permian–Jurassic type) with their deposition–accretion ages estimated as 98–79, 75–72, 89–79, and 155–96 Ma, respectively.Discussion: The provenance of the Precambrian type zircons (mainly 1900 Ma) is considered to derived from the North China Block and the Korean Peninsula. The Permian to Jurassic zircons may have been supplied from Permian to Jurassic volcanic arc in the eastern margin of Asian continent including the Hida Belt in Japan and northeastern China. The provenance of Cretaceous zircons (110–70 Ma) is considered to be Late Cretaceous volcanic arc on the eastern margin of the Eurasian continent such as the Ryoke Belt in Japan island. We conclude as follows. When volcanic activity is strong during 90–85 Ma and 82–78 Ma, the Cretaceous igneous rocks cover on the surface and Cretaceous batholith is uplifted, preventing contact with other places. During the mild volcanic period during 85–82Ma and 78–72Ma, the influx pathway to depositional basins of the sediments recovered due to the erosion.Reference: Jia, S. and Takeuchi, M. 2020, Journal of Asian Earth Sciences, 196, 104342.</p>