A steeply-inclined trajectory for the Chicxulub impact
A steeply-inclined trajectory for the Chicxulub impact
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DOI：
10.1038/s41467-020-15269-x
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发表时间：
2020-05-26
影响因子：
16.6
通讯作者：
Gulick, S. P. S.
中科院分区：
文献类型：
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作者：
Collins, G. S.;Patel, N.;Gulick, S. P. S.
对地球的大规模撞击的环境严重性受到其撞击轨迹的影响。撞击方向和撞击角度影响着蒸发靶的体积和起始深度，同时也影响着喷出物质的运动轨迹。小行星撞击形成了66 Ma的希克苏鲁布陨石坑，对地球环境产生了深远的灾难性影响，但撞击轨迹仍有争议。在这里，我们表明，影响的角度和方向，可以诊断的不对称的地下结构的希克苏鲁布陨石坑。对希克苏鲁伯撞击的三维数值模拟与地球物理观测结果的比较表明，希克苏鲁布陨石坑是由来自东北方向的陡峭倾斜（与水平成45-60度）撞击形成的;几条证据排除了低角度（< 30度）撞击的可能性。与非常浅的或接近垂直的撞击相比，陡峭倾斜的撞击产生几乎对称分布的喷出岩石，并释放更多的改变气候的气体。作者在这里提出了一个三维模型，模拟形成的希克苏鲁布撞击坑。根据希克苏鲁布陨石坑地下结构的不对称性，作者对撞击角度和方向进行了诊断，并认为撞击角度很大（与水平方向成60度角），来自东北方向。
The environmental severity of large impacts on Earth is influenced by their impact trajectory. Impact direction and angle to the target plane affect the volume and depth of origin of vaporized target, as well as the trajectories of ejected material. The asteroid impact that formed the 66 Ma Chicxulub crater had a profound and catastrophic effect on Earth's environment, but the impact trajectory is debated. Here we show that impact angle and direction can be diagnosed by asymmetries in the subsurface structure of the Chicxulub crater. Comparison of 3D numerical simulations of Chicxulub-scale impacts with geophysical observations suggests that the Chicxulub crater was formed by a steeply-inclined (45-60 degrees to horizontal) impact from the northeast; several lines of evidence rule out a low angle (< 30 degrees) impact. A steeply-inclined impact produces a nearly symmetric distribution of ejected rock and releases more climate-changing gases per impactor mass than either a very shallow or near-vertical impact. The authors here present a 3D model that simulates the formation of the Chicxulub impact crater. Based on asymmetries in the subsurface structure of the Chicxulub crater, the authors diagnose impact angle and direction and suggest a steeply inclined (60 degrees to horizontal) impact from the northeast.