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

宇宙源放射性核素^&lt；14&gt；C主要由宇宙射线与氮的相互作用在地球大气中产生。由于宇宙线通量受到地磁和日磁屏蔽的调制，~(14)&gt；C的记录提供了过去太阳活动和地磁场强度的变化信息，在氧化成~(14)&gt；CO_2(放射性碳)后，它成为全球碳循环的组成部分，大气、生物圈和海洋之间的交换。因此，对过去大气碳浓度的分析为探测全球碳循环的变化提供了可能。然而，由于大气中的CO_2浓度对产量的变化很敏感，所以我们需要根据独立的数据来验证过去的产量。本研究以宇宙源放射性核素~(14)Be为研究对象，通过比较~(14)&Gt；C和~(14)Be的丰度来研究其过去的碳循环。一般来说，过去的重建都是从冰芯分析中进行的。从沉积速率较高的湖泊沉积和泥炭沉积等陆相沉积中，我们找到了一种重建陆相沉积的方法。随着对湖泊沉积物10Be分析研究的深入，湖泊沉积物中10Be的浓度明显受地表10Be循环、大气和河流物质供应的影响。基于这一事实，我们在此完成了以下解释：开发了陆相沉积物浓缩方法，扩展了摆动匹配法以确定沉积速率，基于对碧瓦湖岩芯的分析，在地球表面进行了以下解释。

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.