Establishment of a standard high-resolution Plio-Pleistocene stratigraphy using a detrital marine sequence distributed in the Boso Peninsula, Japan.

本课题组对分布于日本博索半岛南部的上更新世千仓群进行了磁性地层学和氧同位素地层学的重建。结果表明，从高斯型臭氧序列到松山型臭氧序列具有可比性，LR04标准曲线得到的氧同位素曲线在MISG16-93之间具有可比性。根据岩性、矿物成分和玻璃碎屑的化学成分，确定了15个Tephra层，命名为Okr1-Okr15，其中8个层为日本中部广泛分布的关键Tephra层。本研究层序的Matuyama/Gauss边界位于MIS103上，而不是LR04时间标度中描述的MIS104上。

Our research group has reconstructed magnetostratigraphy and oxygen isotopic stratigraphy for the Plio-Pleistocene Chikura Group distributed on the southern Boso Peninsula, Japan. The results indicate that, the studied sequence is comparable from the upper Gauss chronozone including the Kaena sub-chronozone to the lower Matuyama chronozone, and the oxygen isotopic curve is correlated between from MIS G16 through 93, which are derived by the LR04 standard curve. We define 15 tephra layers, named as from Okr1 to Okr15, in which 8 layers are identified as key tephra layers widely distributed in central Japan by means of lithologies, mineral asembrages and chemical compositions of glass shards. The Matuyama/Gauss boundary at this studied sequence is situated on MIS 103, not on MIS 104 that is described in the LR04 time scale.