The mechanics of large meteoroid impacts in the Earth’s oceans
The mechanics of large meteoroid impacts in the Earth’s oceans
复制标题
大型流星体撞击地球海洋的机制
DOI：
10.1130/spe190-p121
复制
发表时间：
1982
影响因子：
5
通讯作者：
H. Melosh
中科院分区：
文献类型：
--
作者：
H. Melosh
大型流星体撞击海洋后发生的一系列事件在几个方面不同于撞击陆地。即使流星体大到足以在海底形成一个陨石坑（即直径大于几公里），水的存在也会影响早期事件的性质。陆地撞击和海洋撞击之间的主要区别是海洋撞击后冲击波蒸发的水的膨胀。流星体在目标上沉积能量后会发生蒸汽爆炸。冲击水从3到6兆巴的初始压力膨胀20-30公里/秒的影响，从蒸发的流星体喷射水蒸气和尘埃到大气层几百公里。如此形成的猛烈的蒸汽羽流可以解释以陨石成分为主的尘埃如何分散，形成一个世界范围的尘埃层，正如阿尔瓦雷斯假说所要求的。
The sequence of events subsequent to the impact of a large meteoroid in an ocean differs in several respects from an impact on land. Even if the meteoroid is large enough to produce a crater on the sea floor (that is, larger than a few km in diameter), the presence of water affects the character of the early-time events. The principal difference between land and oceanic impacts is the expansion of shock-vaporized water following an oceanic impact. A steam explosion follows the meteoroid's deposition of energy in the target. Shocked water expands from an initial pressure of 3 to 6 Mbar for 20-30 km/second impacts, ejecting water vapor and dust from the vaporized meteoroid several hundred km into the atmosphere. The violent vapor plume thus formed may explain how dust with a dominantly meteoritic composition can be dispersed to form a world-wide dust layer, as required by the Alvarez hypothesis.