2017 Volume 123 Issue 8 Pages 637-652
We used cores drilled up to depths of 600 m from the central Kanto Plain, Japan, to examine the stratigraphy of the Kazusa and Shimosa groups, and correlate marine intervals with marine oxygen isotopic stages (MIS). Both groups contain sediments from the upper Pliocene (Gauss Chronozone), and the lower to upper Pleistocene. We recognized an unconformity in the Kazusa Group at around 1.6 Ma, which represents a 0.5-1.0 Myr hiatus in the sequence. Both groups comprise cyclic deposits of shallow marine and terrestrial sediments, and there was no significant hiatus after 1.6 Ma in either group. From the depths of correlated marine intervals, we infer that this part of the Kanto Plain, including the cities of Kuki and Kasukabe, was a center of tectonic subsidence around 1.6 Ma.
