R6: Plutonic rocks, volcanic rocks and subduction factory

[R6P-05] Petrological features of the Early Miocene Hachiya Formation in the Chuno Area , Gifu Prefecture, Japan

*Seiya Saijo¹, Toshiro Takahashi² (1. Niigata Univ. Sci., 2. Niigata Univ. Fac. Sci.)

Keywords:Hachiya Formation, adakate, slab melting

The Early Miocene Hachiya Formation is distributed in Chuno area, Gifu Prefecture, is composed mainly of pyroclastic rocks. The Hachiya Formation is considered to the product of igneous activity on the volcanic front or forearc side at the Early Miocene. The Hachiya volcanic rocks can be divided into three groups: rhyolite, dacite, and basalt to andesite. Especially, this dacite indicate similar petrological features to adakite, and andesites are like to the Iwaine Formation andesites.