Fig. 14
From: Review of the Early–Middle Pleistocene boundary and Marine Isotope Stage 19
The Chiba section, Japan. (a) Location of the Chiba section on the Boso Peninsula showing major cities. (b) Schematic geology of the Kanto area showing the depth (metres below sea level) of the base of the Kazusa Group (from fig. 1 of Kazaoka et al. 2015). (c) Chiba section showing faint but discernible parallel bedding in this massive siltstone unit; the location of the GSSP is indicated by a red star (from fig. 10 of Suganuma et al. in press). (d) Detail of the Ontake-Byakubi-E (Byk-E) tephra bed in the Chiba section at the position of the GSSP, showing bioturbation. The GSSP is located at the base of the tephra bed (photo by the author). The GSSP has an astronomical age of 774.1 ± 5 ka and is 1.1 m below the directional midpoint of the Matuyama–Brunhes paleomagnetic reversal (Suganuma et al. in press)