New evidence for the presence of Changbaishan Millennium eruption ash in the Longgang volcanic field, Northeast China

The Changbaishan Millennium eruption (similar to 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, and C-14 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. (C) 2015 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.