New evidence for the presence of Changbaishan Millennium eruption ash in the Longgang volcanic field, Northeast China
New evidence for the presence of Changbaishan Millennium eruption ash in the Longgang volcanic field, Northeast China
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东北龙岗火山田存在长白山千年喷发灰的新证据
DOI：
10.1016/j.gr.2015.01.013
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发表时间：
2015
影响因子：
6.1
通讯作者：
Liu Jiaqi
中科院分区：
文献类型：
--
作者：
Sun Chunqing;You Haitao;He Huaiyu;Zhang Lei;Gao Jinliang;Guo Wenfeng;Chen Shuangshuang;Mao Qian;Liu Qiang;Chu Guoqiang;Liu Jiaqi
长白山千年喷发（约公元940年代）在东北亚周围产生了广泛分布的火山灰层。该火山灰层是格陵兰冰芯以及日本及周边地区海洋、湖泊、考古和海啸沉积物中的标记床。然而，长白山火山以西广泛的沉积物却很少受到关注。在这里，我们展示了来自中国东北龙岗火山田四海龙湾湖的varve沉积物的新地层、地球化学、varve年代学和14C地质年代学数据，该数据延伸到了这次喷发的西风边缘。火山玻璃的独特地球化学特征（从粗面岩到流纹岩）与近端和远端火山灰相似，证实了长白山千年喷发火山灰在湖中的存在，说明火山灰沉积物向西扩散扇。根据 varve 年表，该火山灰玻璃碎片的峰值浓度位置可追溯到公元 953 ± 37 年，该火山灰正上方的放射性碳样本给出的日期为公元 940-1020 年，与这次喷发的最近年龄重叠。该湖中长白山千年喷发灰的出现可以与玛珥湖、泥炭和海洋沉积物等东北亚其他高分辨率档案直接、精确地同步，从而为一系列沉积环境提供了等时标记。
The Changbaishan Millennium eruption (~ AD 940s) produced a widely distributed tephra layer around northeast Asia. This tephra layer serves as a marker bed in Greenland ice cores and in marine, lake, archeological and tsunami sediments in Japan and the surrounding region. However, little attention has been paid to the widespread sediments west of Changbaishan volcano. Here we present new stratigraphic, geochemical, varve chronology, and14C geochronological data from the varved sediments in Lake Sihailongwan, Longgang volcanic field, Northeast China, extending the westerly margin of this eruption. The distinctive geochemical characteristic of volcanic glass (ranging from trachyte to rhyolite), similar to those of proximal and distal tephra, confirmed the occurrence of Changbaishan Millennium eruption ash in the lake, illustrating the westward dispersal fan of the ash deposits. The position of the peak concentration of glass shards of this tephra was dated to 953 ± 37 AD by varve chronology, and the radiocarbon samples immediately above this tephra gave a date of 940–1020 AD, overlapping the most recent ages for this eruption. The occurrence of Changbaishan Millennium eruption ash in this lake enables a direct and precise synchronization with other high-resolution archives in Northeast Asia, such as maar lakes and peat and marine sediments, thus providing an isochronous marker for a range of sedimentary contexts.