舌状岩屑坡

舌状岩屑坡(Lobate debris aprons)是火星上的地质特征,由悬崖下的岩屑堆所组成,被海盗号轨道飞行器首次发现[1][2]。这些特征具有凸起地形并依附于悬崖或陡崖的缓坡,表明岩屑流所塌落的源头峭崖。此外,就像地球上的石冰川一样,舌状岩屑坡可以显示地表线理[3]

 

火星勘测轨道飞行器的浅表探测雷达接收到来自舌状岩屑坡顶部和底部的强烈反射波,这意味着该物体大部分是由纯净的水冰构成(位于两束反射波之间)[4]这也是希腊平原中的舌状岩屑坡为覆盖着一层薄岩层冰川的证据[5][6][7][8][9]。此外,雷达在都特罗尼勒斯桌山群(Deuteronilus Mensae)的研究显示,该地区所有勘查过的舌状岩屑坡都含有冰[10]

凤凰号着陆器的勘测和火星奥德赛号从轨道的研究表明,在遥远的南北高纬度区,冰冻水就保存在火星地表下面。当气候变化时,大部分的冰都以雪的形式沉积下来[11]。而在舌状岩屑坡中发现的水冰的表明,在低纬度地区也能找到水。未来火星定居者将能够利用这些冰层,而不必前往更高纬度地区。与其他火星水源相比,舌状岩屑坡的另一项主要优势是,它们可以很容易地从轨道上发现并确定位置。

下图所示为位于北纬38.2度的佛勒格拉山舌状岩屑坡,凤凰号着陆器降落在北纬68度,因此在舌状岩屑坡中水冰的发现极大地扩大了在火星上轻松获取水冰的范围[12]。在火星赤道附近着陆要容易得多,因此离赤道越近的水资源对移民定居者越有利。

线状底表沉积物 

一些水道的底表显示出沟脊状的纹理,似乎是被水流冲刷的障碍物;这些特征被称为线状底表沉积或线状谷底沉积(LVF)。与舌状岩屑坡一样,它们被认为也富含冰,地球上的一些冰川也显示出这样的特征。

有人认为,线状底表沉积始于舌状岩屑坡[13][14],通过追踪舌状岩屑坡特有的弯脊路径。研究人员已开始相信,它们伸直后就形成了线状谷底沉积脊[15][16][17][18]。线状底表沉积和舌状岩屑坡通常都显示出一种奇特的表面结构,叫做脑纹地形(brain terrain),因为它看起来像人脑的表面[19]

鲁尔谷,下图显示了这些沉积物[20],有时,带线状的底表沉积物显示出V形图案,进一步提供了运动的证据。以下由高分辨率成像科学设备拍摄的鲁尔谷照片展示了这些图案。

图集

另请参阅

参考文献 

  1. ^ Carr, M.  2006.  The Surface of Mars.  Cambridge University Press.  ISBN 978-0-521-87201-0
  2. ^ Squyres, S.  1978.  Martian fretted terrain:  Flow of erosional debrid.  Icarus: 34. 600-613.
  3. ^ ISBN 0-8165-1257-4
  4. ^ 存档副本 (PDF). [2020-10-31]. (原始内容 (PDF)存档于2021-01-23). 
  5. ^ Head, J. et al.  2005.  Tropical to mid-latitude snow and ice accumulation, flow and glaciation on Mars.  Nature: 434. 346-350
  6. ^ 存档副本. [2020-10-31]. (原始内容存档于2012-12-05). 
  7. ^ 存档副本. [2020-10-31]. (原始内容存档于2013-10-12). 
  8. ^ Plaut, J. et al.  2008. Radar Evidence for Ice in Lobate Debris  Aprons in the Mid-Northern Latitudes of Mars. Lunar and Planetary Science XXXIX.  2290.pdf
  9. ^ Holt, J. et al.  2008. Radar Sounding Evidence for Ice within Lobate Debris Aprons near Hellas Basin, Mid-Southern Latitudes of Mars.  Lunar and Planetary Science XXXIX.  2441.pdf
  10. ^ Petersen, E., et al.  2018. ALL OUR APRONS ARE ICY: NO EVIDENCE FOR DEBRIS-RICH “LOBATE DEBRIS APRONS” IN DEUTERONILUS MENSAE 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083).  2354.
  11. ^ Madeleine, J. et al.  2007.  Exploring the northern mid-latitude glaciation with a general circulation model.  In:  Seventh International Conference on Mars.  Abstract 3096.
  12. ^ Archived copy. [2011-09-08]. (原始内容存档于2011-08-22). 
  13. ^ Sourness, C., B. Hubbard, R. Milliken, D. Quincey.  2012.  An inventory and population-scale analysis of martian glacier-like forms.  Icarus 217, 243-255.
  14. ^ Souness, C. and B. Hubbard.   2013.  An alternative interpretation of late Amazonian ice flow:  Protonilus Mensae, Mars.  Icarus 225, 495-505.
  15. ^ Head, J.   & D. Marchant  . Modification of the walls of a Noachian crater in northern Arabia Terra (24E, 39N) during mid-latitude Amazonia n glacial epochs on Mars:  Nature and evolution of lobate debris aprons and their relationships to lineated valley fill and glacial systems. Lunar Planet. Sci. 2006,  37:  Abstract # 1126. 
  16. ^ Kress, A., J. Head.  Ring-mold craters in lineated valley fill and lobate debris aprons on Mars:  Evidence for subsurface glacial ice. Geophys. Res. Lett.  2008, 35: L23206-8. Bibcode:2008GeoRL..3523206K. doi:10.1029/2008gl035501. 
  17. ^ Baker, D.; et al. Flow patterns of lobate debris aprons and lineated valley fill north of Ismeniae Fossae, Mars:  Evidence for extensive mid-latitude glaciation in the Late Amazonian. Icarus. 2010, 207: 186–209. Bibcode:2010Icar..207..186B. doi:10.1016/j.icarus.2009.11.017. 
  18. ^ Kress., A.   & J. Head  . Ring-mold craters on lineated valley fill, lobate debris aprons, and concentric crater fill on Mars:  Implications for near-surface structure, composition, and age. Lunar Planet. Sci. 2009, 40: abstract 1379. 
  19. ^ Levy, J.; et al. Concentric crater fill in Utopia Planitia:  History and interaction between glacial "brain terrain" and periglacial processes. Icarus. 2009, 202 (2): 462–476. Bibcode:2009Icar..202..462L. doi:10.1016/j.icarus.2009.02.018. 
  20. ^ Archived copy. [2010-12-19]. (原始内容存档于2010-06-17). 

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