Subsurface structure of oblique impact craters

倾斜撞击坑的地下结构

基本信息

批准号：
18879389
负责人：
Professor Dr. Thomas Kenkmann
金额：
--
依托单位：
Lehrstuhl Allgemeine Geologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2012-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/18879389?language=en
关键词：
Subsurface structure oblique impact craters

项目摘要

Impacts of asteroids on planetary surfaces usually occur obliquely with an average impact angle of 45°. The impact vector can be analysed by the uneven distribution of ejecta. On Earth ejecta blankets of meteorite craters are very rare and incompletely preserved, but different degrees of erosion often allow to study the crater floor in detail. The working hypothesis of this proposal is that the crater floor flow field is capable to provide direct evidence for oblique impacts via momentum transfer from projectile to the target. The objective is to determine the impact vector of terrestrial craters from the subsurface crater structure and to infer the structural inventory of oblique impacts. For this purpose a field study is planned at the Spider impact crater in Western Australia, which is believed to have been formed by an oblique impact. In a thorough structural analysis deviations from a radial symmetry of the crater floor structure including a study on shock and damaging in different sectors of the crater will be deduced. A kinematic analysis will be performed to quantify dominant flow trajectories which are relevant for reconstruction of the projectile s vector. The analysis will be linked to 3D numerical modeling of the crater floor flow in an oblique impact scenario, A comparison of the Spider structure with other craters is planned to test if structural elements indicative for oblique impacts can be generally applied and to infer the incidence of impact.

小行星对行星表面的影响通常倾斜，平均冲击角为45°。可以通过射出不平衡的分布来分析影响向量。在地球上，陨石石陨石坑的喷射覆盖物非常罕见且不完全保存，但是不同程度的侵蚀通常可以详细研究陨石坑。该提案的工作假设是，火山口地板流场能够通过从弹丸到目标的动量转移来直接证明斜影响。目的是从地下陨石坑结构中确定陆地陨石坑的影响向量，并推断倾斜影响的结构清单。为此，计划在西澳大利亚州的蜘蛛撞击火山口进行实地研究，据信这是由倾斜影响形成的。在彻底的结构分析中，将推导火山台结构的径向对称性，包括对火山口不同部门的冲击和破坏的研究。将进行运动学分析，以量化与弹丸S向量重建相关的主要流动轨迹。该分析将与在倾斜冲击方案中的3D数值建模有关，计划将蜘蛛结构与其他陨石坑进行比较，以测试是否通常可以应用指示倾斜影响的结构元素并推断出影响的事件。