1. Mysterious abrupt carbon-14 increase in coral contributed by a comet.
- Author
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Yi Liu, Zhao-feng Zhang, Zi-cheng Peng, Ming-xing Ling, Chuan-Chou Shen, Wei-guo Liu, Xiao-chun Sun, Cheng-de Shen, Ke-xin Liu, and Weidong Sun
- Subjects
RADIOCARBON dating ,CARBON isotopes ,IMPACT of comets on Earth ,COSMIC rays ,ATMOSPHERE - Abstract
A large and sudden increase in radiocarbon (
14 C) aroundAD773 are documented in coral skeletons from the South China Sea. The14 C 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. The14 C 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 elevated14 C/12 C ratios, as compared to the Earth's atmosphere. The significant input of14 C by comets may have contributed to the fluctuation of14 C in the atmosphere throughout the Earth's history, which should be considered carefully to better constrain the cosmic ray fluctuation. [ABSTRACT FROM AUTHOR]- Published
- 2014
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