Precise correlation of Miocene to early pleistocene in Japanese Islands by means of widespread tephra beds

以日本中部新泻地区为例，研究了日本列岛中新世-早更新世火山灰标志层及其广域对比。新新泻地区早更新世鱼名群中的SK 110和SK 100火山灰层与房总半岛Kiwada组中的Kd 25和Kd 24火山灰层相对应。新泻地区晚上新世西山组的Thw-3和Ftj火山灰层分别与富山湾附近冰见群的YT 4和UN火山灰层对比。此外，还尝试了中新世火山灰层的对比，但很少成功。即中新世Kdg、Gtm.柴田市内须川组中的Skhq和Jng火山碎屑层可与Sng、Stm. Tmhq和Snsg火山灰层分别位于津川地区野村组。这些成果不仅可以为地层记录提供准确的时间标志，而且可以为进一步的环境史研究提供参考。

The Miocene to early Pleistocene tephra marker beds and their widearea correlation were examined in the Japanese Islands, especially based on the Niigata region, central Japan. The early Pleistocene SK110 and SK100 Tephra Beds in the Uonuna Group in the Niigata region were corralated to the Kd25 and Kd24 Tephra Beds in the Kiwada Formation in the Boso Peninsula. The late Pliocene Thw-3 and Ftj Tephra Beds in the Nishiyama Formation in the Niigata region were correlated to the YT4 and UN Tephra Beds in the Himi Group around Toyama Bay respectively. Furthermore, correlation of the Miocene tephra beds were attempted, which have been scarcely successful. Namely, the Miocene Kdg, Gtm. Skhq and Jng Tephra Beds in the Uchisugawa Formation in Shibata City can be correlated to the Sng, Stm. Tmhq and Snsg Tephra Beds in the Nomura Formation in the Tsugawa area respectively. These results will be made in use for not only the exact time marker in the stratigraphic records, but also for the further research of environmental history.