全新世四海龙湾玛珥湖显微火山灰年代学研究

东亚是地球上火山活动最为频繁的地区之一。首先，大规模的火山喷发会给周边居民生存带来威胁，另外，这些火山喷发产生的火山灰也可以为东亚季风演化研究提供绝佳的等时标志。迄今为止，对于东亚岛弧地区的火山喷发是否可以影响至东亚大陆内部，以及有多少火山灰层可作为东亚大区域等时标志尚存争论。本项目拟选用高质量四海龙湾全新世玛珥湖沉积物为研究对象，利用纹层年代学、Pb-Cs、AMS14C定年方法，建立精确的高分辨率时间标尺；利用显微火山灰年代学研究方法，确定显微火山灰层的数量与层位；利用电子探针和激光剥蚀等分析手段，判定各火山灰层的来源；利用高精度玛珥湖定年结果，限定各火山灰层的精确年龄，即对应源区火山喷发的年龄；与日本岛等地显微火山灰记录对比，确定全新世东亚地区广泛分布的火山灰层，为区域古气候研究提供等时参考。这不仅可以用来揭示东亚地区大规模的火山喷发历史，同时，也为区域古气候研究提供绝佳的等时标志。

East Asia is one of the most important volcanic region in the Earth, and those explosive eruptions bring a huge threat to the lives in this region. In addition, tephra from these eruptions can provide excellent marker beds to the studies of East Asia Monsoon. So far, if these eruptions from arc region can effect inland of East Asia, and how many of these tephras can form large area marker layers around East Asia are still in hot debate. In this project, we select high quality Holocene Sihailongwan maar lake sediment as the study object. We will construct a high-resolution precise age model by combination of varve chronology, 210Pb-137Cs, and AMS 14C dating method. Cryptotephra layers and positions will be achieved by using crypto-tephrochronological method. Sources of these tephra layers will be determined by EPMA and LA-ICP-MS analysis on volcanic glass shards. The ages of tephra layers corresponding to volcanic eruptions will be assigned by high-resolution precise age model of maar lake. In addition, Holocene regional tephra marker layers will be established by correlating tephras(and cryptotephras) recorded in the sedimentary archives from Japan. This project not only can reveal explosive eruptive history from this area, but also provide excellent marker horizons to the studies of East Asia Monsoon.