Loading...
Please wait, while we are loading the content...
Similar Documents
The Origin of Eridania Lake and Ma'adim Vallis: An Investigation of Closed Chaos Basins, Hesperian Ridged Plains, and Tectonic Constructs on the Floor of a Large Hypothesized Paleolake on Mars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Baker, David M. H. Head, James W. |
| Copyright Year | 2009 |
| Abstract | Introduction: The varied geomophological characteristics of Ma'adim Vallis on Mars have resulted in a variety of explanations for its formation [1-4]. Among these is a hypothesis [4] suggesting that Ma'adim Vallis was formed by a catastrophic flooding event that occurred near the Noa-chian/Hesperian boundary. Under this scenario, the incision of Ma'adim Vallis was initiated by the overflow of a large ~3,000,000 km 2 Noachian lake (Eridania Lake) spanning the Eridania and Phaethontis quadrangles and approximately delimited by the 1100 m contour line. Upon examining the parameters of the hypothesis, we find that while such an origin for Ma'adim Vallis may seem plausible, there are several issues that still remain unresolved. Among these is the nature and significance of several features on the Eridania Lake floor, including: 1) five major knob fields and the bowl-shaped craters they occupy; 2) widespread ridged plains units of Early Hesperian age; 3) concentric lobate and wrinkle-type ridges; and 4) a large, through-going ridge system. Another issue is the mechanism by which such a large lake would have been filled. Although precipitation is suggested as an input [4], the modest sizes of valley networks entering the lake's catchment area do not appear sufficient to account for the ~500,000 km 3 of water necessary to maintain such a large lake. Recent analyses of open basin lakes on Mars [5] also suggest that groundwater must have contributed to the development of large lakes in the Martian highlands, including Eridania Lake. Here, we look closely at the features listed above in an attempt to construct a history of the Eridania Lake floor and to assess alternative explanations to filling mechanisms for Eridania Lake. Nature of closed chaos basins (knob fields and deepened craters): Early geological maps [6,7] have identified five major knob fields in the Eridania and Phaenthontis quadrangles (Fig. 1). Four of these knob fields (including Ariadnes Colles, Altlantis Chaos, and Gorgonum Chaos) are labeled chaotic terrain units (Hcht), with one (southeast of Ariadnes) labeled as knobby plains material (Apk) [6,7]. THEMIS, MOC, and MOLA data reveal that the knob fields have similar characteristics. Individual knobs are highly degraded, exhibiting pitted textures at THEMIS VIS scale (Fig. 2) with dark capping units and bright flanks where the capping unit has been removed. Larger knobs are mesa-like and tend to occupy the lowest points within the craters, while the smaller knobs are more rounded and are typically found along … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1835.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
