9:15 AM - 9:30 AM
[SGL28-02] Tectonic significance of new Zircon U-Pb ages of sedimentary complexes in the northern Hidaka Belt, central Hokkaido, northern Japan
Keywords:Depositional age, Hidaka Belt, Hidaka Supergroup, LA-ICP-MS, zircon U-Pb age, collision complex
(1) Clastic rocks (Hidaka Supergroup) distributed in the Hidaka belt are within the age of Paleocene ~ early Eocene.
(2) The Hidaka belt is distributed widely across the east-west width of more than 100 km. However, its internal structure and age differences are not clear, and it can not be explained by the accretionary growth model which becomes younger in the eastward.
(3) There is no significant age difference in the eruption age of the three bands of in situ basalts (N-MORB) recognized in the Hidaka belt (Miyashita et al., 1997), and if this is explained by the ridge subduction model, It can be explained only one event.
(4) The Hidaka Supergroup was a sedimentary body mainly composed of turbidite facies filled in the sea area between the Paleo-Japan arc and the Paleo-Kuril arc in Paleocene ~ early Eocene age. After 47 Ma, according to the joining of two arc-trench systems, significant deformation was occurred it. So, it is considered to be "collision complex".
This work was supported by JSPS KAKENHI Grant Number 16K05585.
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