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The similarity of fluidized ejecta blankets of double-layer ejecta (DLE) craters and long run-out landslides: morphometry and modeling

双层喷射物（DLE）陨石坑和长程滑坡的流化喷射物覆盖层的相似性：形态测量和建模

基本信息

批准号：
195366123
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：
2011
资助国家：
德国
起止时间：
2010-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/195366123?language=en
关键词：
similarity fluidized ejecta blankets double

项目摘要

The combined and comparative analysis of impact craters on Mars and Earth was a reasonable and successful way to investigate the effects of volatiles on the excavation process during impact cratering. Main questions raised in this former application could be answered. It could be demonstrated via three-dimensional reconstruction that the Ries crater´s ejecta blanket contains a massive intermediate rampart and is morphometrically similar to the Martian double layer ejecta (DLE) craters. Abundant indicators for the presence of water during deposition and flow were found in two boreholes of the Ries ejecta blanket. The fundamental flow kinematics as well as the spatial and temporal relationship of the ejecta layer deposition of DLE craters could be solved. In the course of the project it became obvious that the inner and outer ejecta layers move in different landslide modes. While the inner ejecta layer is formed by a translational slide that emanates from the crater rim and overruns the proximal parts of the outer ejecta facies the outer more fluid-rich layer moves in a debris flow or debris avalanche mode. We observed a strong topographic and morphologic resemblance between these ejecta facies, and Martian landslides as well as terrestrial long run-out rock avalanches. A first-order feature of the inner layer of DLE ejecta layers and landslides are radial (longitudinal) ridges and grooves parallel to the flow direction. Although such striations appear to be a fundamental phenomenon of fast mass movements their formation is so far poorly understood. We believe that their formation is key to understand the flow mechanism. Their geometry and spacing may even allow to constrain physical parameters of the flow. In the continuation project we will develop a mathematical model based on Voellmy´s equations that is aimed to simulate their formation. A rigorous morphometric analysis provides the basis of input parameters to that model. Likewise characteristic is the formation of extensional furrows and compressive ridges perpendicular to the flow that off-set the radial/longitudinal ridges and grooves. These features develop during the final increments of the flow when the moving masses regain strength. Our morphometric analysis includes these features. The outcome of this proposal is twofold and far-reaching: (i) The comparative quantitative morphometric analysis of surface features of ejecta blankets of DLE craters and landslides will prove or disprove the landslide characteristics of DLE craters. (ii) The fundamental phenomenon of the formation of longitudinal ridges and grooves on fast moving rock masses will be explained.

对火星和地球上的撞击坑进行联合和对比分析，是研究挥发分对撞击坑挖掘过程的影响的合理和成功的方法。在前一次申请中提出的主要问题可以得到回答。通过三维重建可以证明，里斯陨石坑的S喷流毯包含一个巨大的中间堡垒，在形态上类似于火星的双层抛射陨石坑。在里斯喷射层的两个钻孔中发现了大量的沉积和流动过程中存在水的指示器。可以解决DLE陨石坑喷射层沉积的基本流动运动学和时空关系。在工程实施过程中，内、外喷流层以不同的滑坡方式移动的现象日益明显。当内部喷射层是由从火山口边缘发出的平移滑动形成的，并溢出外部喷射相的近端部分时，外部更富流体的层以泥石流或碎屑雪崩的方式运动。我们观察到这些喷出相在地形和形态上与火星滑坡以及陆地上长时间的岩石崩塌有很大的相似之处。DLE喷射层和滑坡内层的一级特征是平行于流动方向的径向(纵向)山脊和沟槽。尽管这样的条纹似乎是快速质量运动的基本现象，但到目前为止，人们对它们的形成知之甚少。我们认为，它们的形成是理解流动机制的关键。它们的几何形状和间距甚至可以限制流动的物理参数。在续集项目中，我们将开发一个基于Voellmy的S方程的数学模型，旨在模拟它们的形成。严格的形态计量分析为该模型提供了输入参数的基础。同样的特征是形成了垂直于水流的伸展沟槽和挤压脊，它们抵消了径向/纵向的脊和槽。当移动的质量块恢复力量时，这些特征在流动的最后增量期间发展。我们的形态计量分析包括这些特征。这一建议的结果是双重和深远的：(I)对DLE陨石坑和滑坡喷发毯子表面特征的比较定量形态分析将证明或否定DLE陨石坑的滑坡特征。(Ii)解释在快速移动的岩体上形成纵脊和纵槽的基本现象。