Sedimentary facies, physical properties, and radiocarbon dates of the GS-KM-1 cores from Komatsugawa district, Tokyo Lowland, central Japan.

Abstract

The latest Pleistocene to Holocene deposits, filling incised valleys carved during the last glacial age, are distributed beneath the Tokyo Lowland, Tokyo Metropolis, central Japan. The GS-KM-1 cores (GS-KM-1A, GS-KM-1B and GS-KM-1C) were drilled at a central part of the Tokyo Lowland, and sedimentary facies, AMS radiocarbon dates and physical properties of the cores were analyzed in detail for clarifying stratigraphy, sedimentary environments and the relationship between sedimentary environment and sediment properties on incised valley fills in the Tokyo Lowland. The latest Pleistocene to Holocene deposits of GS-SK-1 cores consist of fluvial to shallow marine succession as follows, in ascending order: (1) fluvial channel fills of pebble to pebbly sand, (2) flood plain, fluvial channel fills influenced by tidal current and muddy tidal flat deposits, which are characterized by alternation of sand and mud, (3) sandy tidal flat to sand shoal deposits of sand containing blackish to marine shell fragments, (5) inner bay (prodelta to delta front) deposits of massive mud intercalated by thin ripple sand and abundant burrows, and (6) fluvial channels fills to flood plain deposits in deltaplain of alternation of sand and mud. The AMS radiocarbon dates of 21 numbers, covering 11,090 to 2,350 yrBP in radiometric 14 C ages, indicate that the incised valley fills were formed by a set of transgression and regression. Sediment properties, such as N-value, mud contents, bulk densities, magnetic susceptibility, water contents, luminosity and color contrasts tend to vary with horizon and sedimentary facies

Stratigraphic and sedimentologic analyses of the latest Pleistocene to Holocene sediment cores GS-HTB-1 and GS-HTB-2 recovered from the Ishikari coastal plain, Kawashimo, Tobetsu, Hokkaido, Japan

“…Gentaro Kawakami , Junko Komatsubara , Tsumoru Sagayama , Kenji Nishina , Wataru Hirose , Sunao Ohtsu and Katsumi Kimura , 2006, 2004a, 2004b, 2004;, 2006a, 2006b, 2009, 2008b, 2008, 2006, 2008a200619791990 , 2010 Kramer and Lange-Bertalot 1986, 1988, 1991a, 1991b 1250 1 100 Fig. 4 1972Fig.…”