Kaj E. Williams Glen E. Cushing Timothy N. Titus 2020 <div class="article-section__content en main"><p>The transport of H₂O ice along the retreating north polar seasonal CO₂<span>&nbsp;</span>ice cap has previously been modeled and observed. Spectral observations show that H₂O ice forms on the interior of the seasonal cap, while thermal observations show these regions to be consistent with CO₂<span>&nbsp;</span>ice. Prior to the sublimation of the seasonal CO₂, the observed H₂O ice deposits are diminished—and because H₂O ice sublimation rates are extremely slow while in direct thermal contact with CO₂<span>&nbsp;</span>ice, an alternate removal process must be operating. We propose a model where the process of removing these H₂O deposits starts with insolation‐induced basal sublimation of the underlying CO₂<span>&nbsp;</span>ice. This sublimed gas would “seep” upward and into the interface between the two ices, increasing pressure until the gas pressure fractures the cold‐trapped H₂O ice. Small fragments would be suspended while larger fragments would be pushed aside, exposing the underlying CO₂<span>&nbsp;</span>ice.</p></div> application/pdf 10.1029/2020GL087387 en American Geophysical Union Conceptual model for the removal of cold-trapped H2O ice on the Mars northern seasonal springtime polar cap article