縄文時代の石器に使われた岩石および鉱物について　石器製作における石材の選択とその背景

Comprehending patterns of raw material utilization for stone implements can be a key to the solution of questions concerning cultural tradition, cultural behavior, culture areas and trade in prehistoric times. The materials of stone implements reflected “knowledge of requirements (specificastion)” of the tool-makers, and this point is exemplified by stone implements of the Middle Jomon period, the Neolithic period in Japan.<BR>Patterns of raw material utilization for stone implements, at that time, were different among tool types. Evidence is presented which supports the view that Jomon people intentionally selected raw materials according to their “knowledge of tool requirements” (relating to the size and the shape of the tools). In addition, utilization of raw materials for sometypes of stone tools varied between districts. However, such differences confirmed to the intentional hypothesis.<BR>Eight types of stone implements in the Middle Jomon period, arrowheads (sekizoku), drills (ishikiri), points (sentouki, sentoujyousekki), pounding stones (tatakiishi), ground or pitted stones (suriishi, kubomiishi), querns (ishizara), roughly chipped ax-like stone tools (daseisekifu) and polished ax-like stone tools (maseisekifu), have been divided into three categories (1, 2, 3) according to the pattern of raw material utilization.<BR>Category 1 : Arrowheads, drills and points. All these are small light thin and sharp pointed tools which were made from thin flakes and hard compact silicious materials, predominantly obsidian or shale. There were two regional spheres of raw material utilization, the shale area and the obsidian area. Near the producing areas of obsidian in Chubu and Kanto districts, Jomon people tended to use this material. However, in the shale producing district, Tohoku district, Jomon people used often shale (silicious shale and hard shale).<BR>Category 2 : Pounding stones, ground or pitted stones, and querns. These stone implements are big heavy round lumpish tools which were made from round stones and primarily either andesite or sandstone. In every site in Eastern Honshu, these implements were predominantly made of one of these two rock types regardless of region. In addition, such characteristic materials used for category 1, such as obsidian and shale (silicious shale or hard shale), were rarely utilized for this category.<BR>Category 3 : Roughly chipped ax-like stone tools and polished ax-like stone tools. These are the middle weight-thickness implements for which various kinds of raw materials were used, except for obsidian and shale (silicious shale or hard shale). The typical regional patterns of raw material utilization could not be found among the sites.