Green mosses date the Storegga tsunami to the chilliest decades of the 8.2聽ka cold event

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• 作者：Stein Bondevik^a ; ^b ; ^{stein.bondevik@hisf.no} ; Svein Kristian Stormo^c ; Gudrun Skjerdal^d
• 关键词：Storegga tsunami ; Isolation basins ; Chlorophyll ; Radiocarbon dating ; 8.2 ka cold event
• 刊名：Quaternary Science Reviews
• 出版年：2012
• 期刊代码：78_02773791
• 类别：ear
• 出版时间：29 June, 2012
• 卷：45
• 期：Complete
• 页码：1-6
• 文件大小：1078 K

摘要

Chlorophyll in dead plants ordinarily decomposes completely before permanent burial through exposure to light, water and oxygen. Here we describe 8000-year-old terrestrial mosses that retain several percent of its original chlorophyll. The mosses were ripped of the land surface, carried 50-100聽m off the Norwegian coast of the time, and deposited in depressions on the sea floor by the Storegga tsunami. A little of the chlorophyll survived because, within hours after entraining it, the tsunami buried the mosses in shell-rich sediments. These sediments preserved the chlorophyll by keeping out light and oxygen, and by keeping the pH above 7鈥攖hree factors known to favour chlorophyll's stability. Because the green mosses were buried alive, their radiocarbon clock started ticking within hours after the Storegga Slide had set off the tsunami. Radiocarbon measurement of the mosses therefore give slide ages of uncommon geological precision, and these, together with a sequence of ages above and below the boundary, date the Storegga Slide to the chilliest decades of the 8.2聽ka cold event at 8120-8175 years before AD聽1950. North Atlantic coastal- and fjord- climatic records claimed to show evidence of the 8.2 cold event should be carefully examined for possible contamination and disturbance from the Storegga tsunami.