Publication Date:
2017-06-01
Description:
Widespread Amazonian-aged fluvial channels have been mapped proximal to Lyot crater, a ~225 km diameter impact basin in the northern lowlands of Mars. Comparable in area to some Noachian/Hesperian fluvial systems, their morphology differs, being dominated by broad, shallow braided channels. Using new developments in the study of cratering, water inventory and climate history, we assess eight different models for their origin. Dewatering of excavated ice-rich Lyot ejecta and contact melting from hot Lyot ejecta superposed on surface ice deposits are the most plausible channel origins. The existence of this extensive Amazonian fluvial system is attributed to: (1) the large size of Lyot, and its consequent hot ejecta, and (2) the presence of surface ice at the time of impact, attributed to obliquity changes redistributing polar ice to the mid-latitudes, a relatively common occurrence in martian geologic history.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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