Detailed description of specific features of tephra has recently disclosed a number of tephras spread over extensive areas in and around Japan. The present paper gives an overview of such widespread tephras of late Quaternary in Japan and discusses their significances in several problems regarding the Japanese archaeology. 1) Widespread tephras can be classified into three types: large-scale plinian airfall pumice, large-scale ignimbrite and coignimbrite ash falls. The third type of tephra should be the dominant class of widespread tephra. Fine-grained vitric ashes of this type, represented by the Kikai-Akahoya (K-Ah), Aira-Tn (AT) and Aso-4 ashes, cover most of the Japanese islands and adjacent areas, forming important time-markers in the upper Quaternary sequences. 2) The characterization of tephras for identification is made from various viewpoints. However, accurate determination of refractive indices of volcanic glass shards and phenocrysts, together with chemical data and other criteria, have enabled most successful characterization of the tephra layers and interregional correlation. 3) Of the widespread tephra occurring in and around Japan two are alkalic in componitin and are the products of the two Korean volcanoes of the Holocene age: the Baegdusan-Tomakomai (B-Tm) and Ulreung-Oki (U-Oki) ashes. The B-Tm is recognized on Hokkaido and the northern part of Honshu, where a reliable archaeological age is given around the 11th century. The U-Oki occurs on central Honshu, where five radiocarbon ages of around 9.300y.B.P. were obtained. 4) Recognition of the widespread tephras in archaeological sites, especially the AT and K-Ah ashes, has compelled us to revise some former views on archaeological chronology, bh in the neolithic and paleolithic ages. A number of archaeological assemblages were reacovered from below AT (21, 000-22, 000y.B.P., determined from 24 radiocarbon dates). Diversity in technological traditions and rapid cultural change, however, appear to begin immediately after the eruption of AT. The neolithic Jomon ceramic culture began about 10, 000y.B.P., during which K-Ah ash (6, 300y.B.P., determined from 41 radiocarbon dates) provides the definite datum plane in the archaeological sequence. The K-Ah eruption would have given heavy impacts on the Japanese Jomon world. Some K-Ah event and was reoccupied several hundred years ago by bearers of the different cultural tradition.
In Kyushu Upper-Paleolithic culture, which is mainly based on knife-blades, can be divided into five periods from the earliest to the latest according to the stratigraphy of the volcanic ash, sets of stone tools, and the typology and technology of stone tools. It has been suggested that AT, which resulted from a wide range of tephra, accumulated from 21, 000 to 22, 000 years ago. Previous to this the Upper-Paleolithic culture is to be divided into the earlies and the early period, and on and after that the middle, the late and the latest. As for the earliest period, little has been known about stone tools due to lack of data. On the other hand, with regard to the latest period, obscrity connected with stone tools still remains for the knife-blade industry seems to have blended with the following micro-blade industry. In the early period various kinds of knife-blades were existent, hence the industry of knife-blades was probably at its height. Points is a characteristic found in the middle period in Higashi Kyushu, and that period seems to have a close relation with the Inland Sea and the Kinki districts. On the other hand, a variety of trapezoides developed in Nishi Kyushu, and they seem to have formed the nucleus of the set of stone tools together with the knife-blades. That is, in the middle period two distinctive localized stone tools developed: Higashi Kyushu Type and Nishi Kyushu Type. Although this regionalism was handed down to the late period, it became somewhat obscure with the lapse of time. It seems to be the case that in Kyushu differences in the stone tools found in the industries of knife-blades have a close connection with flora and fauna in different environments and with human life based on these flora and fauna. Centering around Kyushu the analysis of stone tools in Paleolithic times in southwestern Japan has been conducted by means of multivariate analysis. The results show that after AT, localization took place in northwestern Kyushu and central and eastern Kyushu. Differences in the sets of the stone tools suggest that different life styles were evolving between the two regions. However, it seems to be the case that at least in the early and at a certain stage of the late period of Phase II, the standardization of the stone tools between the two regions was in progress and that the standardized culture spread over a wide area of southwestern Japan. On the other hand, stone tools in the middle period in east Kyushu are different in quality, and the cultural traits seem to have spread not only over northwestern Kyushu but also all over Japan proper. Moreover, in the Kanto district has bien absirned there were some similarities in stone tools not only between the earliest and the middle period but also between the early and the late period. Thus, it seems that there was a correlation beteen these temporal and regional changes of stone tools and natural environments. That is, it can be hypothesized that in the early and at a certain stage of the late period of Phase II, the stone-tool culture based on hunting such as wild boars and food gathering was in progress in somewhat humid forest environments. And as for the east Kyushu stone tools in the middle period, it can be assumed that they were correlated with the coldness, dryness and deforestation and that hunting ctivities aiming at grassland animals such as horses and bison were under way.
Study of the paleolithic culture based on the stratigraphy had begun with an excavation of the Iwajuku site, Gunma Prefecture, and advanced after 1968, when so-called “After Tsukimino-Nogawa” cultural stratigraphy was established. More than 10 cultural layers are found from the Tachikawa Loam which is 3 to 7m thick and devided into 6 or 8 strata by tephras. Four main industries can be distinguished in the cultural layers; (1) industry mainly composed of becs industry, (2) knife-like backed blade industry, (3) microblade industry and industry mainly composed of points. Paleolithic materials in the Kanto district were examined on the following 7 items; (1) scale of the site based on the number of artifacts, (2) concentration of artifacts, (3) distribution of fired pebble heaps, (4) stone tool assemblages, (5) lithic composition, (6) types of knife-like backed blade and (7) blade technique and its blanks. These analyses enabled to make a correspondence between cultural layers among sites in upper Nogawa River on the Musashino upland, and analysed sites were classified into 3 types; (a) the site with a single cultural layer, (b) the site composed of continuous cultural layers, (c) the site composed of several discontinuous cultural layers. The continuous cultural layers had a tendency to produce bigger amount of artifacts than the discontinuous cultural layers. Changes in the lithic feature of discontinuous cultural layers seem to be rapid, suggesting an intermittent occupation of the site. This phenomenon can be recognized not only successive cultural layers in a site, but also cultural layers of the same strata among different sites. Comparison between the cultural layers below the AT (Aira-Tn ash) and those above the AT showed that lithic features changed remarkably at the AT boundary. It is interesting that changes of the lithic tradition had a close correlation with the environmental change.
A large shell mound called Mazukari shell-mound (YAMASHITA, 1978) was found in 1978 to be buried 12m under the ground surface, at Utsumi Town in the south part of the Chita Peninsula, Aichi Prefecture in Central Japan. Several hundred pieces of Kozanji-type pottery (the middle Earliest Stage of Jomon Age) are included in the collected remains. Tegillara granosa, dated at 8, 330±260y.B.P. (GaK-7950) occurred with these potteries. Many kinds of fossil shells, foraminifers as well as Akahoya Tephra (about 6, 300y.B.P.) were found in the Mazukari shell mound. These features and the 14C dating suggest that the sediments were formed by Jomon Transgression. There are Hayashinomine shell-mound, Shimizunoue shell-mound, Otofukudani remains and Shimobessho are near the Mazukari shell-mound. The following sea-level changes since 9, 000y.B.P. are deduced from the elevation of these remains and the upper limit of marine the sediments. ca. 9, 000y.B.P. ca-14m ca. 7, 000y.B.P. ca+1m ca. 6, 000y.B.P. ca+4.5-5.0m ca. 4, 500y.B.P. ca+1m ca. 3, 000y.B.P. ca+2m
The Juno Peaty Site is situated on the Shibakawa lowland in the eastern part of Omiya City, Saitama Prefecture, and was investigated on the field from 1977 to 1981. The investigation was conducted to examine the natural environment of this site by the cooporation of archaeologist, geologist and many biologists. As the results, archaeological remains were found abundantly and useful observations were carried out, and many samples for scientific analysis were obtained to reconstruct the Juno's natural environment. This paper deals with a summary of the Juno Peaty Site with mainly geological evidences and several points of the problem to reconstruct of natural environment of this site. Especially, height and age of the highest sea level on the Holocene Transgression (Jomon Transgression) and palaeovegetation in the Jomon Age are described. Rising of sea level of Jomon Transgression in this site stagnated temporarily in the Kurohama stage (ca. 5, 700y.B.P.) showh by Kurohama Sand Bed with wave cut platform and trace fossils at 1m height on recent sea level, and thereafter, more risen sea level reached ca. 3m height on recent sea level in Moroiso-a stage. This 3m height indicates a upper limit of marine deposit in the highest sea level stage. Therefore it is presumedthat the highest sea level of Jomon Transgression stay on 3m height or more in the Moroisoa stage (ca. 5, 300y.B.P.) of Early Jomon Age. On the palaeovegetation in Jomon Age it is thought generally that the laurel forest (Cyclobalanopsis) had covered on the Pacific coast of Japan from Early Jomon Age downward. In the site, however, it was found out that the deciduous broad-leaved forest (Lepidobalanus) was dominant during the Jomon Age. This aspect is in contrast with the viewpoint that the laurel forest covered on the area of the Pacific coast in Japan, and it is characteristic feature found over the central part of Kanto Plain.