SGER: An Impact Event at the Onset of the Younger Dryas: Search for Evidence from the Western United States and Europe

SGER：新仙女木期开始时的影响事件：从美国西部和欧洲寻找证据

• 批准号: 0745840
• 负责人: Kenneth Verosub
• 金额: --
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0745840&HistoricalAwards=false
• 关键词: SGER; Impact; Event; Onset; Younger

The proposed work will test whether the onset of the Younger Dryas (about 12,900 years ago) was caused by a cometary impact over the Laurentide Ice Sheet. In particular, the team will seek to determine 1) whether the magnetic properties of iron spherules found at the based of the Younger Dryas at many sites are consistent with formation from a cometary impact, 2) whether evidence for ejecta from the impact event can be found in lacustrine sequences in the western United States where the Younger Dryas boundary is already known to be present but where evidence for an impact has not yet been sought, and 3) whether a dark layer at the base of unit in Europe that has correlated with the Younger Dryas contains material that would be consistent with the hypothesis.Scientific Merit: There is enough physical evidence for an impact at the onset of the Younger Dryas that careful additional work seems warranted. If the hypothesis is correct, it will produce such a fundamental change in our understanding of the causes of abrupt climate change.Broader Implications: The causes and consequences of large-scale, global climatic change are still not well-understood. Finding a new mechanism for an important, recent, global climate event will significantly advance our knowledge of the processes that drive climatic variations. It will also provide fundamental insights into how modern climatic variations will be affected by similar processes.

这项拟议中的工作将测试新仙女木（约12，900年前）的开始是否是由彗星撞击劳伦泰德冰盖造成的。特别是，该小组将寻求确定1）在新仙女木底部许多地点发现的铁球的磁性是否与彗星撞击形成的磁性一致，（二）是否可以在美国西部的湖泊序列中找到撞击事件喷出物的证据，那里已经知道新仙女木边界存在，但撞击的证据还没有3）在欧洲与新仙女木有关的一个暗层是否包含与假设相一致的物质。科学价值：有足够的物理证据表明在新仙女木开始时有一次撞击，因此需要进行进一步的仔细研究。如果这一假设是正确的，那么它将使我们对气候突变原因的认识发生根本性的变化。更广泛的影响：大规模的全球气候变化的原因和后果仍然没有得到很好的理解。找到一个重要的，最近的，全球气候事件的新机制将大大推进我们对驱动气候变化的过程的认识。它还将为现代气候变化如何受到类似过程的影响提供基本见解。