Be-10 Variations in Dome Fuji Ice Core During the Last Deglaciation

HR: 1340h
AN: PP33A-1006 [Abstracts]
TI: Be-10 Variations in Dome Fuji Ice Core During the Last Deglaciation
AU: * Uchida, T
EM: tmk@dges.tohoku.ac.jp
AF: Institute of Geology and Paleontology, Graduate school of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan, Sendai, 980-8578, Japan
AU: Horiuchi, K
EM: kh@cc.hirosaki-u.ac.jp
AF: Department of Earth and Environmental Sciences Faculty of Science and Technology, Hirosaki University, 3 Bukyo-chou, Hirosaki, Aomori, 036-8561 Japan, Hirosaki, 036-8561, Japan
AU: Yasudomi, Y
EM: kh@cc.hirosaki-u.ac.jp
AF: Department of Earth and Environmental Sciences Faculty of Science and Technology, Hirosaki University, 3 Bukyo-chou, Hirosaki, Aomori, 036-8561 Japan, Hirosaki, 036-8561, Japan
AU: Sugawara, A
EM: kh@cc.hirosaki-u.ac.jp
AF: Department of Earth and Environmental Sciences Faculty of Science and Technology, Hirosaki University, 3 Bukyo-chou, Hirosaki, Aomori, 036-8561 Japan, Hirosaki, 036-8561, Japan
AU: Matsuzaki, H
EM: hmatsu@n.t.y-toyo.ac.jp
AF: MALT, Faculty of Technology, The University of Tokyo, 11-16 Yayoi 2-choume, Bunkyou-ku, Tokyo 113-0032 Japan, Tokyo, 113-0032, Japan
AU: Motoyama, H
EM: motoyama@pmg.nipr.ac.jp
AF: National Institute of Polar Research, 9-10, Kaga 1-choume, Itabashi-ku, Tokyo 173-8515, Japan, Tokyo, 173-8515, Japan
AU: Shibata, Y
EM: yshibata@nies.go.jp
AF: Environmental Chemistry Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan, Tsukuba, 305-8506, Japan
AU: Minoura, K
EM: minoura@mail.tains.tohoku.ac.jp
AF: Institute of Geology and Paleontology, Graduate school of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan, Sendai, 980-8578, Japan
AB: Cosmogenic Be-10 is produced in the atmosphere by an interaction of cosmic ray particles and nitrogen and oxygen atoms. The Be-10 is then quickly attached to aerosols and falls on the surface of the land and sea. Assuming Be-10 in an ice core reflects the variations of the production rate of the nuclide, it is possible to know the history of the cosmic ray flux from an ice core record of the nuclide. Several Be-10 records in the Holocene epoch have been obtained from ice cores from Greenland (Beer et al., 1988, 1990; Finkel and Nishiizumi, 1997) and Antarctica (Raisbeck et al., 1990; Steig et al., 1996, Bard et al., 1997; Horiuchi et al., 2007). The records show Be-10 variations relevant to the known periodicities and amplitudes of the solar activity, which, as well as the intensity of the earth’s magnetic field, controls the cosmic ray flux in the atmosphere (Lal and Peters, 1967; Masarik and Beer, 1999). However, the detailed Be-10 records of the last deglaciation are very few (Finkel and Nishiizumi, 1997) and much less investigated than those of the Holocene epoch. In this paper, we present a Be-10 record of the last deglaciation, which is obtained from an ice core retrieved from Dome Fuji station, Eastern Antarctica (77° 19・#338; S, 39° 42・#338; E). The Be-10 was analyzed by using an accelerator mass spectrometry (AMS) of MALT at the University of Tokyo, Japan. One of the problems that should be considered when we investigate the past changes in the cosmic rays by using the Be-10 variations is contamination of local meteorological signals. The last deglaciation was marked by large, hemispheric, millennial-scale climate variations: the Bølling-Allerød and Younger Dryas periods in the north and the Antarctic Cold Reversal in the south. Because these events were not coincident in the north and south (Blunier et al., 1998; Blunier and Brook, 2001), the nature of the Be-10 flux variations may be different in Greenland and Antarctica if climatic changes really influenced the Be-10 variations. However, the Be-10 flux variations in the Dome Fuji ice core show a fairly similar profile to those in the GISP2 (Greenland summit) ice core (Finkel and Nishiizumi, 1997). This fact strongly suggests that local effects are not significant for inland Antarctica (and Greenland summit), and shows a clear possibility of inter-hemispheric correlation between Greenland and Antarctica ice cores via Be-10 flux, even in drastic climatic transitions.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 4918 Cosmogenic isotopes (1150)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting