Morphometric analysis of Martian valley network basins using a circularity function
Morphometric analysis of Martian valley network basins using a circularity function
复制标题
使用圆度函数对火星山谷网络盆地进行形态测量分析
DOI：
10.1029/2005je002506
复制
发表时间：
2005
影响因子：
--
通讯作者：
A. Howard
中科院分区：
文献类型：
--
作者：
W. Luo;A. Howard
[1] 本文采用圆度函数来量化 Margaritifer Sinus 地区火星流域盆地的内部形态，并推断导致其当前地貌特征的主要侵蚀过程以及这些过程运行的可能气候条件。圆度函数描述了流域盆地在不同海拔处的伸长率。我们使用了陆地盆地的圆度函数，这些圆度函数被解释为已通过（1）主要与地下水流失相关的侵蚀和（2）主要与降雨和地表径流相关的侵蚀以及月球上陨石坑盆地的圆度函数进行了修改，以便制定能够区分三种地貌类型的判别函数。基于判别函数的火星盆地分类空间格局表明，形态与陆地河流盆地相似的盆地大多聚集在低海拔干流附近，而形态与陆地盆地相似的被解释为地下水侵蚀源的盆地则位于支流附近、海拔较高。后者比前者多。这种空间分布与早期火星持续的类似地球的温暖湿润气候不一致。相反，它更符合早期干燥的气候，中间夹杂着阵发的潮湿期。另外，主流的集中侵蚀也可能是由于水源从降雨变为降雪或穿透硬壳层的侵蚀造成的。
[1] This paper employs a circularity function to quantify the internal morphology of Martian watershed basins in Margaritifer Sinus region and to infer the primary erosional processes that led to their current geomorphologic characteristics and possible climatic conditions under which these processes operated. The circularity function describes the elongation of a watershed basin at different elevations. We have used the circularity functions of terrestrial basins that were interpreted as having been modified by (1) erosion related to primarily groundwater sapping and (2) erosion related to primarily rainfall and surface run-off, as well as the circularity functions of cratering basins on the Moon, in order to formulate discriminant functions that are able to separate the three types of landforms. The spatial pattern of the classification of Martian basins based on discriminant functions shows that basins that look morphologically similar to terrestrial fluvial basins are mostly clustered near the mainstream at low elevation, while those that look morphologically similar to terrestrial basins interpreted as groundwater sapping origin are located near the tributaries and at higher elevation. There are more of the latter than the former. This spatial distribution is inconsistent with a continuous Earth-like warm and wet climate for early Mars. Instead, it is more aligned with an overall early dry climate punctuated with episodic wet periods. Alternatively, the concentrated erosion in the mainstream could also be caused by a change of water source from rainfall to snowfall or erosion cut through a duricrust layer.