Morphology of large valleys on Hawaii - Evidence for groundwater sapping and comparisons with Martian valleys
Morphology of large valleys on Hawaii - Evidence for groundwater sapping and comparisons with Martian valleys
复制标题
夏威夷大山谷的形态 - 地下水流失的证据以及与火星山谷的比较
DOI：
10.1029/jb091ib13p0e175
复制
发表时间：
1986
影响因子：
--
通讯作者：
J. F. Piper
中科院分区：
文献类型：
--
作者：
R. Kochel;J. F. Piper
径流和地下水的侵蚀过程在不同程度上对陆地和火星山谷的形成和演变都很重要。由此产生的通道形态和谷形态似乎是独特的，这取决于这两个过程中占主导地位。我们的实地侦察和形态测量研究的径流和侵蚀山谷的斜坡上的夏威夷和莫洛凯岛在夏威夷表明，山谷类型可以区分使用遥感数据类似于火星的维京海盗轨道图像。形态测量数据的主成分分析清楚地将径流谷与侵蚀谷区分开来。夏威夷的侵蚀山谷，就像它们可能的火星类似物一样，其特征是：（1）陡峭的谷壁和平坦的谷底，（2）圆形剧场的头，（3）低排水密度，（4）缺乏下游支流，（5）上倾支流的频率低，（6）构造和地层控制山谷格局的有力证据。
夏威夷的大峡谷是由地下水供给的，地下水来自高水位的堤坝蓄水层，这些蓄水层被河道切割破坏。在弱胶结砂中进行的水槽实验也通过地下水的抽汲产生了类似的通道。此外，我们模仿了在夏威夷观察到的山谷演变序列，并显示了地下水盗采作为扩大山谷头的主要过程的重要性。这些实验是有用的，在测试的基本思想，如何削弱山谷演变的可变结构和地层。它们还提供了一个模式，用于制定有助于识别地下水枯竭所产生的地貌的地貌标准。
Runoff and groundwater sapping processes are important, to varying degrees, in the initiation and evolution of terrestrial and Martian valleys. The resulting channel morphology and valley morphometry appear to be distinctive, depending upon which of the two processes are dominant. Our field reconnaissance and morphometric studies of runoff and sapping valleys on the slopes of Hawaii and Molokai in Hawaii indicate that valley types can be distinguished using remotely sensed data similar to the Viking orbital imagery of Mars. Principal components analysis of morphometric data clearly separate runoff valleys from sapping valleys. Hawaiian sapping valleys, like their possible Martian analogs, are characterized by: (1) steep valley walls and flat floors, (2) amphitheater heads, (3) low drainage density, (4) paucity of downstream tributaries, (5) low frequency of up-dip tributaries, and (6) strong evidence of structural and stratigraphic control on valley patterns.
The large Hawaiian sapping valleys are fed by groundwater from high-level dike-impounded aquifers breached by channel incision. Flume experiments in weakly cemented sand have produced similar channels by groundwater sapping. In addition, we have mimicked the sequence of valley evolution observed in Hawaii and have shown the importance of groundwater piracy as a major process for widening valley heads. These experiments are useful in testing fundamental ideas concerning how sapping valleys evolve in response to variable structure and stratigraphy. They also provide a model for developing geomorphic criteria useful in the recognition of landforms generated by groundwater sapping.