How big was the Chesapeake Bay impact? Insight from numerical modeling
How big was the Chesapeake Bay impact? Insight from numerical modeling
复制标题
切萨皮克湾的影响有多大？
DOI：
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复制
发表时间：
2005
期刊：
影响因子：
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通讯作者：
K. Wünnemann
中科院分区：
文献类型：
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作者：
G. Collins;K. Wünnemann
弗吉尼亚州切萨皮克湾撞击结构是美国最大的撞击坑。形成陨石坑的撞击器有多大，这个重要的问题仍然没有答案。这主要是由于地震勘探揭示的陨石坑结构的特殊性，使其与其他陆地和地外陨石坑的比较复杂化。切萨皮克湾陨石坑异常结构的一个潜在解释是，撞击时目标的流变变化影响了陨石坑的形成过程。通过数值模拟，我们发现，对于切萨皮克湾撞击现场沉积单元和结晶单元在物质强度上的充分对比，我们可以产生与观测约束一致的最终陨石坑模型，从而可以推断撞击过程中释放的能量；1.753106Mt.在没有目标强度变化的情况下，最终的陨石坑直径很可能是40公里，而不是观察到的80-90公里。
The Chesapeake Bay impact structure, Virginia, is the largest impact crater in the United States. The important question of how large the impactor was that formed the crater remains unanswered. This is primarily due to peculiarities of the crater structure, revealed by seismic exploration, that complicate comparisons with other terrestrial and extraterrestrial craters. One potential explanation for the unusual structure of the Chesapeake Bay crater is that the cratering process was affected by rheologic variations in the target at the time of impact. Using numerical modeling, we find that for a sufficient contrast in material strength between the sedimentary and crystalline units at the Chesapeake Bay impact site, we can produce a model of the final crater that is consistent with observational constraints, and hence we can infer the energy released during the impact, ;1.75 3 10 6 Mt. In the absence of target strength variations, the final crater diameter is likely to have been ;40 km, rather than the observed 80‐90 km.