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Postimpact Evolution of the Southern Hale Crater Ejecta, Mars
Journal of Geophysical Research: Planets ( IF 3.9 ) Pub Date : 2020-08-18 , DOI: 10.1029/2019je006302
J. L. Collins‐May 1 , J. R. Carr 1 , M. R. Balme 2 , N. Ross 1 , A. J. Russell 1 , S. Brough 3 , C. Gallagher 4
Affiliation  

As one of the youngest large (>100 km wide) impacts on Mars, Hale crater offers a unique opportunity to observe well‐preserved deposits of Mars' former interior. We utilize visible imagery (Context Camera [CTX] and High Resolution Imaging Science Experiment [HiRISE]) and elevation data (Mars Orbiter Laser Altimeter [MOLA], High Resolution Stereo Camera [HRSC], and HiRISE stereo pairs) to examine the region south of Hale crater, which contains the greatest density of landforms caused by with the impact. Linear depressions, mounds, and polygons indicate that the ejecta material contained volatiles and underwent substantial postimpact geomorphic evolution after it was emplaced. Ejecta landform formation was facilitated by volatiles, likely water ice displaced from the subsurface during the impact, contained within the material. We suggest that the ejecta flowed into valleys where it acted in a manner similar to terrestrial debris flows, leaving mounds, high‐standing deposits, lobate flow margins, and fan structures. Continued flow and settling of the ejecta then caused deposit dewatering, producing networks of linear depressions, particularly in places where the flows of ejecta were constricted. However, these landforms are not present everywhere, and their formation was likely influenced by topography. This work highlights that, while volatiles were present over much of Hale crater's ejecta blanket, the surface expression of them is spatially variable on local and regional scales.

中文翻译:

火星南部Hale Crater Ejecta的撞击后演变

作为对火星影响最年轻的大型撞击事件(宽度大于100公里)之一,黑尔火山口为观察火星前内部保存完好的沉积物提供了独特的机会。我们利用可见图像(上下文相机[CTX]和高分辨率成像科学实验[HiRISE])和高程数据(火星轨道激光高度计[MOLA],高分辨率立体相机[HRSC]和HiRISE立体对)来检查南部地区黑尔火山口,其中包含最大密度的地貌造成的冲击。线性的凹陷,丘陵和多边形表明,顶出的物质放置后会产生挥发物,并且会在撞击后发生明显的地貌演化。物质中所含的挥发物(可能是水冰在撞击过程中从地下移走)促进了弹射体地形的形成。我们建议,喷出物以类似于陆上泥石流的方式流入山谷,留下土堆,高位沉积物,叶状流动边缘和扇形结构。喷射流的持续流动和沉降继而导致沉积物脱水,形成线性凹陷的网络,特别是在喷射流受限的地方。但是,这些地貌并非随处可见,其形成很可能受到地形的影响。这项工作着重指出,尽管海尔陨石坑的喷射层中大部分存在挥发物,但它们的表面表达在局部和区域尺度上在空间上是可变的。喷射流的持续流动和沉降继而导致沉积物脱水,形成线性凹陷的网络,特别是在喷射流受限的地方。但是,这些地貌并非随处可见,其形成很可能受到地形的影响。这项工作着重指出,尽管海尔陨石坑的喷射层中大部分存在挥发物,但它们的表面表达在局部和区域尺度上在空间上是可变的。喷射流的持续流动和沉降继而导致沉积物脱水,形成线性凹陷的网络,特别是在喷射流受限的地方。但是,这些地貌并非随处可见,其形成很可能受到地形的影响。这项工作着重指出,尽管海尔陨石坑的喷射层中大部分存在挥发物,但它们的表面表达在局部和区域尺度上在空间上是可变的。
更新日期:2020-09-14
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