Japan Geoscience Union Meeting 2015

Presentation information


Symbol S (Solid Earth Sciences) » S-GL Geology

[S-GL38] Lower-Middle Pleistocene Boundary GSSP in the Kazusa Group

Mon. May 25, 2015 11:00 AM - 12:45 PM 102B (1F)

Convener:*Makoto Okada(Department of Earth Sciences, Faculty of Science, Ibaraki University), Yusuke Suganuma(National institute of Polar Research), Osamu Kazaoka(Research Institute of Environmental Geology, Chiba), Chair:Yusuke Suganuma(National institute of Polar Research), Osamu Kazaoka(Research Institute of Environmental Geology, Chiba)

12:30 PM - 12:33 PM

[SGL38-P01] Invitation to the Tabuchi section, central Japan: A candidate GSSP for the Lower-Middle Pleistocene Subseries/Subepoch

3-min talk in an oral session

*Takeshi YOSHIDA1, Itaru OGITSU1, Osamu KAZAOKA1, Makoto OKADA2, Yusuke SUGANUMA3, Koji KAMEO4, Hisashi NIREI5, Nobuyuki AIDA6, Hisao KUMAI7, Naohisa NISHIDA8, Kentaro IZUMI9 (1.Reserch Institute of Environmental Geology, Chiba, 2.Ibaraki University, 3.National Institute of Polar Research, 4.Chiba University, 5.Japan Branch of Geoscience for Environmental Management, 6.Shumei University, 7.Osaka City University, 8.GSJ-AIST, 9.University of Tokyo)

Keywords:Tabuchi section, Lower and Middle Pleistocene

The Tabuchi section is a continuous marine sedimentary succession exposed in the Boso peninsula and is a Lower - Middle Pleistocene boundary GSSP candidate.
From the geological advantages and the easy access to the outcrops, the Tabuchi section seems to be the most suitable for the Lower - Middle Pleistocene boundary GSSP.

Geological characteristics
*Tabuchi section is only candidate representing the Pacific realm.
*Thick L - M Pleistocene sedimentary succession (>3000 m) (2.4 ? 0.5 Ma) .
*Well exposed along the Yoro River with high sed. rates (ca. 2 m/kyr) & no visible breaks.
*Well preserved calcareous nannofossils, planktonic foraminifera, diatoms.
*Standard section for Japanese Pleistocene tephrostratigraphy (>50 ash beds).
*Well established d18O isotope stratigraphy: Kokumoto Fm. corresponds to MIS 20?18.
*M?B boundary is located ca. 1 m above a distinctive, widespread tephra bed (Byk-E).
*High-precision U-Pb zircon age of the Byk-E.
Consistent with the latest astrochronology of marine sediments and Antarctic ice core.
*A basis for immediate comparisons between, magnetostratigraphy, biostratigraphy, O isotope stratigraphy, absolute ages (40Ar/39Ar & U-Pb), and astrochronology.
*Taking the M?B boundary as the primary guide to the L?M Pleistocene boundary, the Byk-E bed would serve as an appropriate level for the GSSP.

There are well developed public transportations. You can reach to Tabuchi section within 2 hours from Tokyo and 3 hours from both international airports. There are big car parks. There are lodge and toilet.
The access to the Tabuchi section is very easy and convenient by car, bus and train with very small walk.