Modeled Subglacial Water Flow Routing Supports Localized Intrusive Heating as a Possible Cause of Basal Melting of Mars' South Polar Ice Cap
Modeled Subglacial Water Flow Routing Supports Localized Intrusive Heating as a Possible Cause of Basal Melting of Mars' South Polar Ice Cap
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模拟的冰下水流路径支持局部侵入加热是火星南极冰盖基底融化的可能原因
DOI：
10.1029/2019je006061
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Arnold N
中科院分区：
文献类型：
--
作者：
Arnold N
火星表面和电离层探测高级雷达(MARSIS)仪器数据中火星南极层状沉积物(SpLD)下约20公里宽明亮的地下雷达反射区域的发现，以及与火星中纬度粘性流动特征有关的两个地质上近期潜在冰川(冰下融化产生的地貌)的发现，表明火星冰层最近的基础融化可能是可能的，可能是由于局部地热加热。根据冰面地形和冰层厚度计算出的冰下水力势面，成功地预测了陆地冰下湖泊和主要排水轴线的位置。在这里，我们使用火星轨道器激光高度计的表面地形和从MARSIS数据得出的SPLD床高程来计算SPLD下面的冰下水力潜势表面，并确定观测到的高反射率区域是否与预测的冰下湖泊位置一致。考虑到陆地上对湖泊位置的预测对基本地形的敏感性，我们得出了1000多个扰动地形(使用MARSIS数据的噪声统计数据)，以推断最可能的冰下水体和排水轴的位置。我们的结果表明，高反射率区域与任何实质性预测的湖泊位置并不一致；然而，附近的三个湖泊位置得到了强有力的预测。我们将这一结果解释为表明高反射率区域(假设解释为液体是正确的)最有可能是被周围寒冷的冰限制的水力隔离的液体斑块，而不是受地形限制的冰下湖泊。
The discovery of an ~20‐km‐wide area of bright subsurface radar reflections, interpreted as liquid water, beneath the Martian south polar layered deposits (SPLD) in data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument, and the discovery of two geologically recent potential eskers (landforms produced by subglacial melt) associated with viscous flow features in Martian midlatitudes, has suggested recent basal melting of Martian ice deposits may be feasible, possibly due to locally elevated geothermal heating. Locations of terrestrial subglacial lakes and major drainage axes have been successfully predicted from subglacial hydraulic potential surfaces calculated from surface topography and ice thickness. Here, we use surface topography from the Mars Orbiter Laser Altimeter and SPLD bed elevations derived from MARSIS data to calculate the subglacial hydraulic potential surface beneath the SPLD and determine whether the observed high reflectance area coincides with predicted subglacial lake locations. Given the sensitivity of terrestrial predictions of lake locations to basal topography, we derive over 1,000 perturbed topographies (using noise statistics from the MARSIS data) to infer the most likely locations of possible subglacial water bodies and drainage axes. Our results show that the high reflectance area does not coincide with any substantial predicted lake locations; three nearby lake locations are robustly predicted however. We interpret this result as suggesting that the high reflectance area (assuming the interpretation as liquid is correct) is most likely a hydraulically isolated patch of liquid confined by the surrounding cold‐based ice, rather than a topographically‐constrained subglacial lake.
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