Sedimentary rocks (sandstone and mudstone) originated from the Shimanto and Chichibu Belt, and schists (psammitic schist, pelitic schist, siliceous schist and greenschist) of the Sanbagawa Belt are dominant. Greenstones (weakly metamorphosed basalt) of the Mikabu Belt are also commonly observed. Some amounts of chert and rare serpentinite are also found, which used to be blocks in sandstone and mudstone matrix of the Shimanto Belt.

Sandstone
Composed mainly of quartz, feldspars and lithic fragments with minor amount of micas. Component grains of this sandstone are generally angular and poorly sorted.
(upper: single-polar, lower: crossed-polars)

Silicious Schist
A rock mainly composed of quartz (ex. chert) deformed due to differential stress during subduction and exhumation. In this picture, horizontally elongated quartz grains due to vertical compression are characteristic under the single-polar. These quartz grains look as single grains under single-polar, but crossed-polars photo shows that they are actually aggregates of fine-grained quartz.
(upper: single-polar, lower: crossed-polars)

Quartz is dominant, followed by subordinate albite (Ca-free plagioclase), muscovite, clinopyroxene, plagioclase (except for albite) and chlorite. Plagioclase and muscovite are considered to be derived from accretionary complex of the Shimanto belt, albite and chlorite are from the Sanbagawa metamorphic belt, and clinopyroxene is from the Mikabu greenstone belt, respectively.

Heavy Minerals

Hornblende and clinopyroxene occupy the dominant proportion, which are followed by metamorphic minerals such as epidote, actinolite and chlorite. Hornblede and clinopyroxene are considered to be derived from the Mikabu greenstone belt, and metamorphic minerals are from the Sanbagawa metamorphic belt.
A remarkable aspect of the Aridagawa is a lack of orthopyroxene, which is one of the representative minerals of volcanic tephras. This infers that there is little or no ash fall in this area.

To be analyzed