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

本课题组对分布在日本博索半岛南部的上新世-更新世千仓群进行了磁地层学和氧同位素地层学重建。结果表明，研究序列从上高斯时臭氧（包括Kaena次时臭氧）到下松山时臭氧具有可比性，从MIS G16到93的氧同位素曲线与LR04标准曲线具有相关性。通过岩性、矿物组分和玻璃碎片化学成分分析，确定了日本中部广泛分布的15层温层，命名为Okr1 ~ Okr15，其中8层为关键温层。本研究序列的Matuyama/Gauss边界位于MIS 103上，而不是LR04时间尺度中描述的MIS 104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.