関東平野中央部，埼玉県菖蒲町で掘削された350mボーリングコア(GS-SB-1 )の層相と堆積物物性

摘要

A 350-m-long sediment core, the GS-SB-1, was recovered at Shobu Town, central Kanto plain. Thiscore was obtained to achieve a standard stratigraphy of the Lower to Upper Pleistocene subsurface geology inthe central Kanto plain. This paper describes basic lithofacies, tephras and physical properties of the GS-SB-1.Physical properties including density, elastic wave velocity, spontaneous potential, and electric resistivity weremeasured. Sixty-nine facies units (unit 1 to unit 69 in descending order) were identified and their relation tophysical properties was discussed. Thirty-nine tephras were found from GS-SB-1 core, and two of them correlateto the Ontake Pm-1 tephra (9.90-10.90m in depth, ca 100ka), and the Ks5 tephra (182.85-182.87m in depth).Stratigraphic boundary between the Shimosa Group and the Kazusa Group is situated between 165m and 184m indepth. Nine marine deposits were identified based on sedimentary facies and diatom assemblages reported by Nayaet al. (2009).