Earth-scientific features of the Tateiwa-type stone harvesting knives from the Tateiwa Sites

Abstract

Major and trace elements and rare earth elements and X-ray diffraction analyses were conducted on stone harvesting knives from the Shimonokata Site and Yakenosyo Site as well as the Tateiwa Sites. Additionally, analyses were performed on gravels of red purple mudstone from the Wakino Subgroup, Kanmon Group in the northern Kyushu. The stone harvesting knives are made from a combination of red purple - gray mudstone and very fine sandstone including calcic concretions. Red purple mudstones from the Yakiyama River indicate higher Ni content, higher total rare earth elements content and lower As content than that of red purple mudstones from the Murasaki River. This suggests that it is possible to detect differences in the source of the stone materials by using these chemical compositions. Chemical compositions of stone harvesting knives from the Tateiwa Sites fall within the composition ranges of the Yakiyama River. This suggests that the source of the stone materials is the Sengoku Gorge area of the Yakiyama River.