R6: Plutonic rocks, volcanic rocks and subduction factory

[R6P-07] Sr-Nd isotopic composition of Miocene felsic volcanic rocks
in the Kamo area, Niigata Prefecture

*Naoki TAKAHASHI¹, Toshiro TAKAHASHI² (1. Niigata Univ. Sci, 2. Niigata Univ. Sci)

Keywords:Volcanic rocks, Felsic volcanic rock, NE Japan arc, Miocene

Miocene felsic volcanic rocks in the Kamo area, Niigata Prefecture, can be divided into two groups, E-group (17-14Ma) and D-group (11-8Ma), based on the age and the geochemical features. Sr-Nd isotopic compositions of the E-group rhyolite indicate that it may have been formed by partial melting of lower crust. On the other hand, the geochemical features of D-group rhyolite suggest that they were formed by differentiation from mafic magma and assimilation of crustal materials.