Radiocarbon and Stable Isotope Analyses on the Earliest Jomon Skeletons from the Tochibara Rockshelter, Nagano, Japan

Abstract

This study presents the results of carbon and nitrogen isotopic analyses of six human skeletons excavated from the Tochibara rockshelter (Nagano, Japan). The human skeletons were reported to be accompanied by "Oshigata-mon" type pottery dating to the Earliest Jomon period (8900 BP approximately 6600 BP). A radiocarbon determination from charcoal associated with the human remains was reported to be 8650 +/180 BP (GaK-1056). However, the depositional context of human skeletons was uncertain because they were recovered by excavations that were dug by prescribed levels. Our results indicated that these skeletons date to the Earliest Jomon period; the 14C determinations place these remains between 8260 +/100 BP (TERRA-b030799ab38) and 8580 +/100 BP (TERRA-b011300a35). This coincides with the archaeological evidence that these specimens are some of the oldest Jomon skeletal materials. Furthermore, delta-13C and delta-15N values provide evidence for the first reconstruction of the diet of an inland Earliest Jomon population. Although the distribution of data indicated a possibility that they had exploited small amounts of seafood, the isotopic data point to this group having relied heavily on a terrestrial ecosystem based on C3 plants.