Lake Suigetsu varved sediment project: terrestrial radiocarbon calibration model and inter-regional comparison of climate changes

大气放射性碳的长期记录提供了丰富的信息，既可以作为环境中碳循环的记录，也可以作为所有14 C测年的基础。全新世大气放射性碳记录由树木年轮提供，被认为（几乎）是可靠的。而12410 ~ 26000 BP时期的沉积则是以海相沉积为基础的，受海相储层效应的影响。此外，缺乏26，000至50，000 BP期间的大气的相应信息。该项目将建立一个晚更新世（10，000/50，000 BP）的放射性碳校准模型，该模型基于从日本水月湖每年层积的湖相沉积物中回收的陆地材料，主要是不受海洋储层影响的落叶树叶化石。该项目还将利用高分辨率或超高分辨率的花粉记录，定量重建季风地区过去15万年的气候变化。将利用地磁偏移和火山灰层等连接点建立剖面。因此，该项目将有助于国际科学努力，利用放射性碳信息确定环境变化的时间和速度，并了解全球碳循环过去的变化。该项目还将有助于对气候变化的因果机制进行假设检验，特别是关于亚洲、北大西洋、南极洲和许多其他海洋和陆地记录中末次冰期-间冰期循环中D/O事件的相对时间。

Long term records of atmospheric radiocarbon provide a wealth of information, both as records of carbon cycling in the environment and as a basis for all 14C dating. The Holocene atmospheric radiocarbon record is provided by tree rings and is considered to be (almost) robust. However, that of the period from 12,410 to c.26,000 BP is based on marine sediments which are influenced by the marine reservoir effect. Also, the corresponding information for the atmosphere for the period 26,000 to 50,000 BP is lacking. This project will establish a radiocarbon calibration model for the Late Pleistocene (10,000 / 50,000 BP) based on terrestrial material, mostly deciduous tree leaf fossils which are free from marine reservoir effects, recovered from the annually laminated lacustrine sediments of Lake Suigetsu, Japan. The project will also produce quantitatively reconstructed climate changes of the Monsoon regions for the last 150,000 yeas using high or ultra-high resolution pollen records. The profile will be established using tie-points such as geomagnetic excursions and tephra layers. The project will therefore contribute to international scientific endeavour in using radiocarbon-based information to determine the timing and rates of environmental changes, as well as understanding past changes in the global carbon cycle. The project will also contribute to hypothesis testing about the causal mechanisms of climate change, especially concerning the relative timing of D/O events in Asia, North Atlantic, Antarctica and many other marine and terrestrial records through the last glacial-interglacial cycle.