Timothy N. Titus Cynthia Dinwiddie 2021 <div class="article-section__content en main"><p>Linear dune gullies on poleward‐facing Martian slopes are enigmatic. Formation by CO₂‐ice block or snow cornice falls has been proposed based on optical imagery of bright, high‐albedo features inside gully channels. Because these features often resemble patchy frost residue rather than three‐dimensional blocks, more evidence is needed to support the ice‐block formation mechanism. Satellite imagery captured two simultaneous airborne plumes with in‐channel sources at the Russell crater megadune, thrust up and dispersed outward along the path of linear dune gullies. We use spectral data analyses, climatic analyses of bolometric temperatures and thermal modeling to further develop the mechanistic framework for linear dune gully development. Basal sublimation and CO₂<span>&nbsp;</span>gas venting likely cause CO₂‐ice‐block detachment and falls from gully alcoves in southern early spring, accompanied by ice‐block offgassing and saltation of sands and coarse silts that are redeposited around gully channels, and lofting of sublimation lag (coarse dust/silt) into airborne plumes.</p></div> application/pdf 10.1029/2020GL091920 en American Geophysical Union Airborne dust plumes lofted by dislodged ice blocks at Russell crater, Mars article