Cosomogenic isotope production and global carbon cycles during the past 10,000 years

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The cosinogenic radionuclide ^<14>C is produced in the Earth's atmosphere mainly by the interaction of cosmic rays with nitrogen. Since the cosmic ray flux is modulated by geo-and heliomagnetic shieldings, records of ^<14>C provide information on variations in the solar activity and the geomagnetic field intensity in the past, After oxidation to ^<14>CO_2 (radiocarbon) becomes a constituent of the global carbon cycle, and exchanges between atmosphere, biosphere and the ocean. The analysis of the past atmospheric ^<14>C concentration therefore provides the possibility to detect change of global carbon cycle. However, since the atmospheric ^<14>CO_2 concentration is sensitive to changes in the ^<14>C production rate, we need to verify the past production rate from the independent data. In this study, we focused on a cosmogenic radionuclide, ^<10>Be, as a trace of.pastproduction changes.In this study, we aimed to investigate the past carbon cycle by the comparison of ^<14>C concentration with ^<10>Be abundance. In general, the past ^<10>Be reconstructions have carried out from ice core analyses. We had an approach to reconstruct the ^<10>Be change from the terrestrial deposition such as lake sediment and peat depositions with higher sedimentation rate. As research marches on 10Be analysis of the lake sediments, it became very obvious that the ^<10>Be concentration of the lake sediments can be strongly influenced by the ^<10>Be cycle on the earth's surface ; supply of the material form atmosphere and river. Based on the this fact, we here complete following interpretation into a report ; developed method of ^<10>Be concentration of the terrestrial sediments, extended wiggle matching method to determine the sedimentation rate, ^<10>Be on the earth's surface based on the analysis of a core from the lake Biwa.