Small crater modification on Meridiani Planum and implications for erosion rates and climate change on Mars

Journal of Geophysical Research E: Planets
By: , and 

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Abstract

A morphometric and morphologic catalog of ~100 small craters imaged by the Opportunity rover over the 33.5 km traverse between Eagle and Endeavour craters on Meridiani Planum shows craters in six stages of degradation that range from fresh and blocky to eroded and shallow depressions ringed by planed off rim blocks. The age of each morphologic class from <50–200 ka to ~20 Ma has been determined from the size-frequency distribution of craters in the catalog, the retention age of small craters on Meridiani Planum, and the age of the latest phase of ripple migration. The rate of degradation of the craters has been determined from crater depth, rim height, and ejecta removal over the class age. These rates show a rapid decrease from ~1 m/Myr for craters <1 Ma to ~ <0.1 m/Myr for craters 10–20 Ma, which can be explained by topographic diffusion with modeled diffusivities of ~10−6 m2/yr. In contrast to these relatively fast, short-term erosion rates, previously estimated average erosion rates on Mars over ~100 Myr and 3 Gyr timescales from the Amazonian and Hesperian are of order <0.01 m/Myr, which is 3–4 orders of magnitude slower than typical terrestrial rates. Erosion rates during the Middle-Late Noachian averaged over ~250 Myr, and ~700 Myr intervals are around 1 m/Myr, comparable to slow terrestrial erosion rates calculated over similar timescales. This argues for a wet climate before ~3 Ga in which liquid water was the erosional agent, followed by a dry environment dominated by slow eolian erosion.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Small crater modification on Meridiani Planum and implications for erosion rates and climate change on Mars
Series title Journal of Geophysical Research E: Planets
DOI 10.1002/2014JE004658
Volume 119
Issue 12
Year Published 2014
Language English
Publisher American Geophysical Union
Contributing office(s) Astrogeology Science Center
Description 26 p.
First page 2522
Last page 2547
Online Only (Y/N) N
Additional Online Files (Y/N) N