Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE

Patrick S. Russell; Nicolas Thomas; Shane Byrne; Kenneth E. Herkenhoff; Kathryn E. Fishbaugh; Nathan Bridges; Chris Okubo; Moses P. Milazzo; Ingrid J. Daubar; Candice J. Hansen; Alfred S. McEwen

doi:10.1029/2008gl035790

USGS · 70032652

Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE

Patrick S. Russell·Nicolas Thomas·Shane Byrne·Kenneth E. Herkenhoff·Kathryn E. Fishbaugh·Nathan Bridges·Chris Okubo·Moses P. Milazzo·Ingrid J. Daubar·Candice J. Hansen·Alfred S. McEwen

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Abstract

North-polar temporal monitoring by the High Resolution Imaging Science Experiment (HiRISE) orbiting Mars has discovered new, dramatic examples that Mars1 CO2-dominated seasonal volatile cycle is not limited to quiet deposition and sublimation of frost. In early northern martian spring, 2008, HiRISE captured several cases of CO2 frost and dust cascading down a steep, polar scarp in discrete clouds. Analysis of morphology and process reveals these events to be similar to terrestrial powder avalanches, sluffs, and falls of loose, dry snow. Potential material sources and initiating mechanisms are discussed in the context of the Martian polar spring environment and of additional, active, aeolian processes observed on the plateau above the scarp. The scarp events are identified as a trigger for mass wasting of bright, fractured layers within the basal unit, and may indirectly influence the retreat rate of steep polar scarps in competing ways.

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Patrick S. Russell, Nicolas Thomas, Shane Byrne, Kenneth E. Herkenhoff, Kathryn E. Fishbaugh, Nathan Bridges, Chris Okubo, Moses P. Milazzo, Ingrid J. Daubar, Candice J. Hansen, Alfred S. McEwen. 2008-12-06. Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE. https://doi.org/10.1029/2008gl035790

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