Petrological characteristics of serpentinite mélange from southwest Japan: Nagato tectonic belt and metamorphic terrance of north Kyushu

Abstract

The metamorphic rocks accompanied by serpentinite melange in the Tenzan area. Saga Prefecture consists of low-P/T type metamorphic rocks lacking high-P/T type metamorphic rocks. On the other hand, serpentinite melange from the Nagato Tectonic belt in Yamaguchi Prefecture contains high-P/T type metamorphic rocks and meta-trondhjemite as blocks in the serpentinite matrix. The metamorphic rocks from the Tenzan area and the Nagato Tectonic belt have been considered as a member of the Sangun belt. Considering of geochemistry of metamorphic rocks and compositions of chromite in serpentinite, the metamorphic rocks of the Tenzan area can be correlated with those of the Higo metamorphic terrane.