used for Palaeolithic stone artefacts
Late Palaeolithic *stone artefacts. It is well-known that in this area such andesite is present in several places; Mt. Hotaka, Mt. Arafune, Mt. Happu, and the Takeshi River area. Mt. Hotaka is located on the northern part of Gunma Prefecture. We found that at this place there are several lava flow layers containing this andesite. Mt. Arafune and Mt. Happu are situated on the western part of the same Prefecture. We noticed that each of these mountains has only one lava flow layer containing andesite. The Takeshi River flows through the northern part of Tochigi Prefecture. We observed that in this river area there are many cobbles of the same quality.
In this article we indicated the specimens of black glassy andesite sampled at each of these sources. All samples were studied under a polarising microscope.
In conclusion it was found that we can classify each of the source specimens by identifying the structure of ground mass, the quantity of glass and magnetite, the size of pyroxene, and the existence of microscopic holes. The sourcing method based on polarising microscopic observation is thought to have sufficient reliability for the sourcing of stone tools made by this andesite. It is hoped that with further studies the stone implements manufactured by this method can help us identify the sources.
* Equivalent to the European Upper Palaeolithic
