Stratigraphy around Kansai International Airport - reconstruction of the Plio-Pleistocene Osaka Group in the southern Osaka Basin
Abstract
Tectonic sedimentary basin in Osaka is formed by the activation of fault system with E-W trending fault (MTL and AL) and N-S trending fault (Ikoma fault and Osaka wan fault). This sedimentary basin during Quaternary time is aligned in the central part of Japan (Takemura, 1985). In this basin, thick sedimentary sequences deposited and these are including marine clay deposit. These marine clay deposit are formed at least 15 layers. The stratigraphy of the Osaka Group in the hill areas was summarized on the basis of intercalation of marine clay bed and volcanic ash layers. The stratigraphy of submarine strata at Kansai International Airport is summarized based on correlation of four 400m deep cores obtained during 1994 and 1995, and previous results published by Nakaseko et. al., (1984). In 2007, deep borehole core drilling was carried out at Kansai Airport again. It over 1200m depth and this drilling point is most near central axis in Osaka sedimentary basin. In this study, we are analysis by micropaleontological, tephrochronological and magnetostratigraphical method, and correlated around borehole data. The sequences are called upper group (Kukojima) and lower group (Sennanoki) (Nakaseko et al., 1984). These Kukojima and Sennanoki formations are include marine deposit. In this study, we can analysis deeper part formation and it appeared that deeper deposits are formed in the lake. It means these are non-marine deposit not include marine clay and seems to big lake because of main grain size are silt and sand. In this poster, we would like to show the stratigraphy at center of Osaka basin and its characteristics.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMPP43C1540K
- Keywords:
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- 1520 Magnetostratigraphy;
- 1641 Sea level change (1222;
- 1225;
- 4556);
- 1861 Sedimentation (4863);
- 3022 Marine sediments: processes and transport;
- 8169 Sedimentary basin processes