Tephrochronological study for Archaeological Ruins and Remains in the Izu Islands.

在伊豆诸岛，史前遗迹和遗迹夹在火山沉积物中。阐明了该火山矿床的地层学特征，从而探讨了火山活动的繁荣和时代。并取得了如下结果.在伊豆群岛的火山沉积物中发现了广泛分布的火山灰、Aira-Tn火山灰和K-Ah火山灰，并定义了广泛分布的火山灰。2.在八条岛，在东山破火山口的浮石流沉积物顶部发现了Aira-Tn火山灰。测定了浮岩流的C-14年龄. K-Ah灰烬在大岛的Takinokuchi遗址和八条岛的Yuhama遗址被发现。两者都与最新绳文时代的遗迹有关。在伊豆诸岛的火山沉积物中发现了一些玻璃灰，并对其进行了追踪。这些火山岩在不久的将来可能被视为重要的标志火山岩。

In Izu islands, prehistoric ruins and remains are sandwitched in volcanic deposits. Stratigraphy of this volcanic deposits clarifyed, thus prosperity and decay and age of the volcanic activities were examined. And obtained following results.1. Both widespread tephras, Aira-Tn ash and K-Ah ash were discovered in the volcanic deposits of Izu islands and the widespread tephras are defined.2. In Hachijo islnd, Aira-Tn ash discovered at the top of pumice flow deposits of Higashi-yama caldera. C-14 age of the pumice flow was measured.3. K-Ah ash were discovered in Takinokuchi ruins in Oshima island and Yuhama ruins in Hachijo island. Both relate with remains belongs to the latest Jomon Period.4. Some vitric ash discovered in volcanic deposits in the Izu islands and traced. These tephras could be treated as important marker-tephras in the near future.