Extensive Middle Amazonian mantling of debris aprons and plains in Deuteronilus Mensae, Mars: Implications for the record of mid-latitude glaciation
Extensive Middle Amazonian mantling of debris aprons and plains in Deuteronilus Mensae, Mars: Implications for the record of mid-latitude glaciation
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火星 Deuteronilus Mensae 中亚马逊河中部广泛的碎片围裙和平原覆盖：对中纬度冰川作用记录的影响
DOI：
10.1016/j.icarus.2015.06.036
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发表时间：
2015
期刊：
影响因子：
3.2
通讯作者：
J. Head
中科院分区：
文献类型：
--
作者：
D. Baker;J. Head
火星的中纬度地区最近积累了大量富含冰的物质。这一记录包括碎片停机坪，被解释为被碎片覆盖的冰川，可能代表着更大范围冰盖的保存残留物。我们通过检查Deuronilus Mensae的碎屑停机坪和周围的平原来评估以前冰川范围的可能性。从火星勘测轨道器(MRO)环境(CTX)和高分辨率成像科学实验(HiRISE)相机图像绘制和记录了地貌单位和地层关系，并根据陨石坑大小-频率分布估计了陨石坑保留年龄。在研究区内观察到三个主要单元：碎屑停机坪、低平原和高平原。碎屑停机坪表现出其他地方和以前研究中记录的这些特征的典型特征，包括完整的流动线条和模式、凸起向上的剖面以及多节的和大脑地形表面结构。碎片围裙的年龄下限估计为0.9Ga。碎屑停机坪叠加在下界年龄为3.3-3.5Ga的较低平原单元上。50-100米厚的上平原单元叠加了碎屑停机坪地貌和下平原单元，最适合的最小年龄为0.6年龄段。上平原单元表现出大气侵位地幔物质的特征，包括细粒性质、升华结构、旋回分层、复盖性和广泛的空间分布。碎屑停机坪上的上平原的破裂和随后的升华/侵蚀导致了碎屑停机坪上的许多表面纹理。高平原单元也从低平原和高原被侵蚀，证据是火山口内部以及高原的墙壁和顶部上的孤立的高平原区块。虽然在研究区域内的平原上没有观察到确凿的证据来诊断以前的冷冰盖，但这种地貌和单元可能不太发达或不存在，就像地球上经常发生的那样，并可能在后来的地幔更替事件中被覆盖和重新加工。这些观察表明，厚厚的富冰地幔沉积至少延伸到亚马孙早期/中期边界附近，并与Deuronilus Mensae的冰川消退阶段重叠。
The mid-latitudes of Mars are host to a record of recent episodes of accumulations of ice-rich materials. The record includes debris aprons, interpreted to be debris-covered glaciers, that may represent the preserved remnants of a much more extensive ice sheet. We assessed the possibility of former glacial extents by examining debris aprons and the surrounding plains in Deuteronilus Mensae. Geomorphic units and stratigraphic relationships were mapped and documented from Mars Reconnaissance Orbiter (MRO) Context (CTX) and High Resolution Imaging Science Experiment (HiRISE) camera images, and crater retention ages were estimated from crater size–frequency distributions. Three major units are observed within the study area: debris aprons, lower plains, and upper plains. Debris aprons exhibit characteristics typical for these features documented elsewhere and in previous studies, including integrated flow lineations and patterns, convex-upward profiles, and knobby and brain terrain surface textures. A lower bound on the age for debris aprons is estimated to be 0.9 Ga. Debris aprons are superposed on a lower plains unit having a lower bound age of 3.3–3.5 Ga. A 50–100 m thick upper plains unit superposes both debris apron landforms and lower plains units and has a best-fit minimum age of 0.6 Ga. The upper plains unit exhibits characteristics of atmospherically-emplaced mantle material, including fine-grained nature, sublimation textures, cyclic layering, draping character, and widespread spatial distribution. Fracturing and subsequent sublimation/erosion of upper plains on debris aprons has contributed to many of the surface textures on debris aprons. The upper plains unit has also been eroded from the lower plains and plateaus, evidenced by isolated blocks of upper plains in the interiors of craters and on the walls and tops of plateaus. While no conclusive evidence diagnostic of former cold-based ice sheets are observed in the plains within the study region, such landforms and units may have been poorly developed or absent, as is often the case on Earth, and would have been covered and reworked by later mantling episodes. These observations suggest that emplacement of thick ice-rich mantle deposits extended at least to near the Early/Middle Amazonian boundary and overlapped with the waning stages of glaciation in Deuteronilus Mensae.
DOI：
--
发表时间：
2013
期刊：
--
影响因子：
--
作者：
Hambrey, MJ
通讯作者：
Hambrey, MJ