Spatio-Temporal Distributions of Middle to Late Jomon Pithouses in Oyumino, Chiba (Japan)

Abstract

Oyumino is a residential area of ca. 605 hectares located in proximity to the western shores of the Tokyo Bay and on the southern end of the Shimousa tableland in the Bosō peninsula (Kantō region, Central Japan). Topographically it is characterised by a series of short and narrow fluvial valleys cross-cutting an upland with an average elevation of ca. 30-50 meters. From an administrative viewpoint, the district is part of the Chiba prefecture, a region which has been intensely excavated from the 60s onward as part of an urban development plan encompassing the entire southern Kantō region (the national archaeological site database of the Nara National Research Institute for Cultural Properties has 24,749 archaeological sites recorded for Chiba).The geographic combination of the Shimousa tableland and the rich intertidal zones of the Tokyo bay has been often linked to the extraordinary high density of settlements attributed to the Jōmon period (ca. 16,000 -2500 cal BP), an archaeological phase characterised by the presence of hunter-gatherers with a rich material culture and comparatively high levels of sedentism. About one third of the identified sites can be attributed to this archaeological phase, and Chiba offers one of the best contexts for studying these prehistoric hunter-gatherers, due to a considerable number of settlements associated to shellmiddens, which offer invaluable information concerning the subsistence strategies of the Jōmon communities. 7,8 The Jōmon settlements of Oyumino have been investigated between 1974 and 2001 with a series of emergency excavations related to the development of the "Chiba South-East New Town Area". The archaeological investigations have identified 19 Jōmon settlements; most of them have been extensively excavated, yielding over 380 round-shaped dwellings dug into the ground (pithouses) with a diameter between 4 and 8 meters. This offers an incomparable dataset for studying patterns between the traditional intra-site (< 200m) and regional (> 5km) scale of analysis and to switch the basic unit of analysis from arbitrary defined concepts such as "site" or "settlement" to the single residential feature.The dataset focuses on the interval between the Middle and Late Jōmon periods (ca. 5500-3200 cal BP) which, with 364 identified pithouses, represents the largest portion of this rich settlement data. Residential features of this period are often distributed following an annular plan (along with other features such as storage pits, shell deposits, etc.) with an unoccupied central plaza in the middle. The Oyumino dataset shows how these large settlements (known as kanjōshūraku in Japanese 8 ) were associated to smaller clusters of residential features. The typical inter-distance between the kanjōshūraku and these satellite settlements were extremely small -often within the range of 100-200 meters 4 -, suggesting how a "site" or "settlement" based analytical units are not suitable in this case. Data paperSpatio-Temporal Distributions of Middle to Late Jomon Pithouses in Oyumino,...