Importance of aeolian processes in the origin of the north polar chasmata, Mars

Recent developments in planetary Aeolian studies and their terrestrial analogs

“…Materials beneath the polar ice cap are the proposed sediment source for the circumpolar dunefields (Thomas and Weitz, 1989;Howard, 2000;Byrne and Murray, 2002;Edgett et al, 2003;Rodriguez et al, 2007;Tanaka et al, 2008;Warner and Farmer, 2008). Spectral analysis of strata visible in the Basal Unit and the Upper Layered Deposits (ULDs), exposed in troughs eroded through the polar ice cap, have provided support for this hypothesis.…”

“…The margin of the north polar sand sea is where changes in Martian sand dunes were first documented, illustrated through the disappearance of sand dunes over three Martian years (almost 6 Earth years) . Steep scarps present along the margins of the north polar chasmata (canyons), large reentrants carved through the polar cap and into the underlying polar layered deposits, strongly influence the direction and intensity of prevailing winds coming off of the polar ice fields (Warner and Farmer, 2008). The location and orientation of sand dunes near the north polar chasmata indicates the likely source of the polar sand is from within the layered deposits themselves (Warner and Farmer, 2008;Kocurek and Ewing, 2010).…”

“…Steep scarps present along the margins of the north polar chasmata (canyons), large reentrants carved through the polar cap and into the underlying polar layered deposits, strongly influence the direction and intensity of prevailing winds coming off of the polar ice fields (Warner and Farmer, 2008). The location and orientation of sand dunes near the north polar chasmata indicates the likely source of the polar sand is from within the layered deposits themselves (Warner and Farmer, 2008;Kocurek and Ewing, 2010). The southern high latitudes do not have a large erg comparable to the one surrounding the north polar cap, but 1190 dune fields have been identified poleward of 50°S latitude , indicating that Aeolian activity is likely as much a part of the story in southern polar regions as it is in the north.…”

The construction of Chasma Boreale on Mars

“…Stratigraphic analyses of the exposed portions of Chasma Boreale-a large canyon 500 km long, up to 100 km wide, and nearly 2 km deep-have led most researchers to favour an erosional process for its formation following initial NPLD accumulation. Candidate mechanisms include the catastrophic outburst of water 5 , protracted basal melting 6 , erosional undercutting 7 , aeolian downcutting [7][8][9] and a combination of these processes 10 . Here we use new data from the Mars Reconnaissance Orbiter to show that Chasma Boreale is instead a long-lived, complex feature resulting primarily from non-uniform accumulation of the NPLD.…”

“…This has led some researchers to conclude that Chasma Boreale was formed as a result of aeolian processes, rather than a basal melt event 8,9,13 . Until recently, however, neither comprehensive NPLD stratigraphy nor large-scale basal topography has been available to construct a full history of Chasma Boreale development or more fully test formation hypotheses.…”