最古老海啸有何记录？国际最新研究发现逾亿年前琥珀或保存痕迹

Core Insights - The research published in the open-access journal "Scientific Reports" suggests that amber deposits found in ancient deep-sea sediments may represent one of the oldest tsunami records known to date [1][3] Group 1: Research Findings - The study indicates that large amber deposits discovered in Hokkaido, Japan, may have been transported into the ocean by one or more tsunamis occurring approximately 116 to 114 million years ago [1][3] - The authors highlight the difficulty in identifying ancient tsunami traces due to the ability of waves to reshape coastlines, making it challenging to distinguish tsunami deposits from those caused by other high-energy events like storms [3][4] - The research team analyzed silica sediments rich in amber from the Nakagawa quarry, which formed around 115 million years ago during the Early Cretaceous period when the area was deep-sea seabed [3][4] Group 2: Methodology and Observations - Using fluorescence imaging technology, the authors observed significant deformation in the amber samples, exhibiting a "flame structure," which indicates that the amber was still in a softened state during deposition and underwent deformation before fully hardening [4] - This deformation suggests that a large amount of amber was likely washed into the sea by one or more tsunamis, briefly exposed to air before sinking and being covered by sediment, thus preserving it [4][7] Group 3: Implications - The authors conclude that amber and other terrestrial sediments transported to open waters may hold significant value for investigating ancient large-scale destructive events such as tsunamis [7]