Formation of central uplift structures in large, complex impact craters: Mechanical importance of pseudotachylitic breccia zones and prominent dislocations in the development of the Vredefort Dome, South Africa

大型复杂撞击坑中中央隆起结构的形成：假速岩角砾岩带和南非弗里德堡圆顶发育过程中显着位错的机械重要性

• 批准号: 30307603
• 负责人: Professor Dr. Wolf Uwe Reimold
• 金额: --
• 依托单位: Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung (MfN)
• 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 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/30307603?language=en
• 关键词: Formation; central; uplift; structures; large

Despite the fact that large meteorite impact belongs to the least understood processes in planetary geology, detailed structural studies of terrestrial impact structures, let alone of large complex ones, are still in their infancy. Considerable uncertainty centres around the formation of central uplifts, more specifically, the (1) geometric and kinematic significance of prominent dislocations, (2) the temporal and mechanical relationships between continuous and discontinuous deformation and (3) the mechanical role of voluminous pseudotachylitic breccia bodies in this process. These issues are addressed in a combined field-structural, laboratory and 3D geometric restoration analysis using the Vredefort Dome, a deeply eroded relic of a central uplift and best preserved natural laboratory on Earth for such study. The study will also test whether shock-induced melt, i.e., pseudotachylitic breccia, was transported from highpressure to low-pressure sites during formation of the central uplift, und thus pertains directly to solving the pseudotachylite controversy . Structural analyses proposed herein are intimately linked with the petrographic and geochemical and analyses of pseudotachylitic breccia delineated in the companion proposal by Prof. U. Reimold.

尽管大量的陨石影响属于行星地质学中最知名的过程，但陆地撞击结构的详细结构研究，更不用说大型复杂的结构仍处于起步阶段。大量不确定性集中在中央隆起的形成中，更具体地说，（1）突出脱位的几何和运动学意义，（（2）连续变形和不连续变形之间的时间和机械关系以及（3）在这个过程中大量伪型硫醇的机械作用。这些问题在使用Vredefort Dome的野外结构，实验室和3D几何恢复分析中解决了，Vredefort Dome是地球上中央隆升和最佳保存的天然实验室的深度侵蚀的遗物。该研究还将测试冲击诱导的熔体，即假硫代基质角度，在中央隆起的形成过程中从高压转移到低压位点，因此直接与解决伪谷链的争议直接相关。本文提出的结构分析与美国雷莫尔德教授的同伴建议中描述的假偶核角砾岩的岩石学和地球化学和分析密切相关。