文章基本信息

标题：Mysterious abrupt carbon-14 increase in coral contributed by a comet
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作者：Yi Liu ; Zhao-feng Zhang ; Zi-cheng Peng 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2014
卷号：4
DOI：10.1038/srep03728
出版社：Springer Nature
摘要：A large and sudden increase in radiocarbon (¹⁴C) around AD 773 are documented in coral skeletons from the South China Sea. The ¹⁴C increased by ~ 15‰ during winter, and remain elevated for more than 4 months, then increased and dropped down within two months, forming a spike of 45‰ high in late spring, followed by two smaller spikes. The ¹⁴C anomalies coincide with an historic comet collision with the Earth's atmosphere on 17 January AD 773. Comas are known to have percent-levels of nitrogen by weight, and are exposed to cosmic radiation in space. Hence they may be expected to contain highly elevated ¹⁴C/¹²C ratios, as compared to the Earth's atmosphere. The significant input of ¹⁴C by comets may have contributed to the fluctuation of ¹⁴C in the atmosphere throughout the Earth's history, which should be considered carefully to better constrain the cosmic ray fluctuation.