Geological evolution of Ares Vallis on Mars: Formation by multiple events of catastrophic flooding, glacial and periglacial processes
Geological evolution of Ares Vallis on Mars: Formation by multiple events of catastrophic flooding, glacial and periglacial processes
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火星上阿瑞斯山谷的地质演化：由灾难性洪水、冰川和冰缘过程的多重事件形成
DOI：
10.1016/j.icarus.2009.02.029
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发表时间：
2009
期刊：
影响因子：
3.2
通讯作者：
M. Pondrelli
中科院分区：
文献类型：
--
作者：
A. Pacifici;G. Komatsu;M. Pondrelli
战神谷是火星最大的外流通道之一。利用近期火星任务（MGS、2001奥德赛和火星快车）的高分辨率图像，我们研究了战神谷及其山谷臂，利用火星快车高分辨率立体相机（HRSC）的高分辨率立体能力进行了三维分析。在我们看来，战神谷的特点是灾难性的洪水景观部分叠加冰相关的形态。灾难性的洪水地貌包括侵蚀阶地、沟槽地形、流线型高地、巨型沙洲、悬垂沙洲和瀑布状特征。与冰有关的地貌包括可能的冰砾特征、热岩溶洼地和图案化地面。我们的调查表明，在整个西方时代，战神谷及其山谷的手臂曾被几次时间分散的灾难性洪水所雕刻，这些洪水来自Iani，Hydaspis和Aram混沌。地貌证据表明，灾难性的洪水被冰覆盖，火星当时的气候条件与现在的气候条件相似。在每一次灾难性的洪水结束时，冰块都会搁浅，形成厚厚的停滞的死冰体。每一次灾难性的洪水之后都有一个相对短暂的温暖潮湿的气候条件，这是灾难性洪水造成的。在这一时期，热岩溶洼地形成，液态水形成蜿蜒的河道，冰接触沉积物被冰壁溪流侵位。最后，气候变成了类似于今天的寒冷干燥的条件，冰团升华了。
Ares Vallis is one of the greatest outflow channels of Mars. Using high-resolution images of recent missions to Mars (MGS, 2001 Odyssey, and Mars Express), we investigated Ares Vallis and its valley arms, taking advantage of 3-dimensional analysis performed using the high-resolution stereo capability of the Mars Express High Resolution Stereo Camera (HRSC). In our view, Ares Vallis is characterized by catastrophic flood landscapes partially superimposed by ice-related morphologies. Catastrophic flood landforms include erosional terraces, grooved terrains, streamlined uplands, giant bars, pendant bars, and cataract-like features. Ice-related morphologies include probable kame features, thermokarstic depressions, and patterned grounds. Our investigations outline that throughout the Hesperian age, Ares Vallis and its valley arms had been sculpted by several, time-scattered, catastrophic floods, originating from Iani, Hydaspis and Aram Chaos. Geomorphological evidence suggests that catastrophic floods were ice-covered, and that climatic conditions of Mars at this time were similar to those of the present day. At the end of each catastrophic flood, ice masses grounded, forming a thick stagnant dead-ice body. Each catastrophic flood was followed by a relatively brief period of warmer-wetter climatic conditions, originated as a consequence of catastrophic flooding. During such periods thermokarstic depressions originated, liquid water formed meandering channels, and ice-contact deposits were emplaced by ice-walled streams. Finally, the climate turned into cold-dry conditions similar to the present-day ones, and ice masses sublimated.