同心坑沉积

同心坑沉积(concentric crater fill)是指撞击坑坑底大部分地区绵延着许多道平行山脊的地形地貌，这种类型的撞击坑在火星中纬度地区很常见Dickson, J. et al.  2009.  Kilometer-thick ice accumulation and glaciation in the northern mid-latitudes of Mars:  Evidence for crater-filling events in the Late Amazonian at the Phlegra Montes.  Earth and Planetary Science Letters.，并普遍认为是冰川运动所造成的Head, J. et al.  2006.  Extensive valley glacier deposits in the northern mid-latitudes of Mars:  Evidence for late Amazonian obliquity-driven climate change.  Earth Planet. Sci Lett: 241.  663-671.Levy, J. et al.  2007.  Lineated valley fill and lobate debris apron stratigraphy in Nilosyrtis Mensae, Mars:  Evidence for phases of glacial modification of the dichotomy boundary.  J. Geophys. Res.:  112.。火星上被称为都特罗尼勒斯桌山群和普罗敦尼勒斯桌山群的地区都分布着许多同心坑沉积。

说明
同心坑沉积，与舌状岩屑坡和线状谷底沉积一样，被认为都富含水冰Levy, J. et al.  2009.  Concentric crater fill in Utopia Planitia:  History and interaction between glacial "brain terrain" and periglacial processes.  Icarus: 202. 462-476.，有时在同心坑沉积上发现的巨砾，据认为它们是从撞击坑坑壁上剥落的，然后随着冰川的运动而被移离Marchant, D. et al.  2002.  Formation of patterned ground and sublimation till over Miocene glacier ice in Beacon valley, southern Victorialand, Antarctica.  Geol. Soc. Am. Bull:114.  718-730.Head, J. and D. Marchant.  2006.  Modification of the walls of a Noachian crater in northern Arabia Terra (24E, 39N) during mid-latitude Amazonian glacial epochs on Mars:  Nature and evolution of lobate debris aprons and their relationships to lineated valley fill and glacial systems.  Lunar Planet. Sci: 37.  Abstract # 1126.，地球上的漂砾也以类似的方法被移动。

高分辨率成像科学设备(HiRISE)拍摄的高清照片显示，同心坑沉积的部分表面覆盖了一层被称为细胞闭合型和细胞开放型脑纹地形的奇特图案。这种地形类似人脑，据信这是由于堆积的灰尘及其他碎屑的表面裂缝以及部分表面冰升华所致，而产生裂缝的原因则是重力和季节性冷热二种因素共同作用的结果Mellon, M.  1997.  Small-scale polygonal features on Mars:  Seasonal thermal contraction cracks in permafrost.  J. Geophysical Res: 102. 25,617-625,628.Ley, J. et al.  2009.  Concentric crater fill in Utopia Planitia:  History and interaction between glacial "brain terrain" and periglacial processes.  Icarus: 202.  462-476.。

 另请参阅 
 卡西乌斯区 
 火星气候
 都特罗尼勒斯桌山群 
 锐蚀地形
 撞击坑
 冰川
 火星冰川
 普罗敦尼勒斯桌山群 
 火星水文

参考文献




Category:火星表面特征