Basalt weathering in an Arctic Mars-analog site

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

“…This discussion section links results presented in Figures 1-13 to prior scholarship on cold climate rock-surface processes. The results clearly confirm findings by Rapp [23], Hall [14,[24][25][26], Dixon [27][28][29][30][31][32][33][34][35], Thorn [36][37][38], their collaborators, and others [40][41][42][43][44][45][46][47][105][106][107] on the importance of chemical processes in cold climate geomorphic settings. However, Figures 1-13 also reveal new details of rock-surface chemical l processes at the nanoscale that, we hope, opens the eyes of cold-climate researchers who only perceive "minimal chemical weathering" [39] when they see bare rock (e.g., Figures 1, 11 and 13a).…”

“…Silica glaze has long been noted in Antarctic samples [74,106,117], and others have previously observed intercalation of different rock coatings, namely silica glaze and sulfate crust in Victoria Land, Antarctica [74], and rock varnish and silica glaze on the Tibetan Plateau [89]. Similarly, the different rock coatings observed here have been noted in Sweden [31], Greenland [118], Iceland [119], and Antarctica [120].…”

On the provenance of GEMS, a quarter century post discovery

“…Laboratory experiments show that GEMS are highly susceptible to rapid aqueous alteration at temperatures as low as 433 K (160 °C), Nakamura- . Terrestrial amorphous silicates (e.g., obsidian) are readily leached with oxidation of Fe and a decrease in density and element/Si ratios under both experimental and natural weathering conditions, including during long-term ($1 ka) storage in ice (Koenderink et al, 2000;Vesavage et al, 2015). Similar alteration conditions may exist in small, icerich asteroids and comets (Harju et al, 2014;Yabuta et al 2017;Noguchi et al, 2017;Rietmeijer, 2018).…”

Source‐to‐Sink Terrestrial Analogs for the Paleoenvironment of Gale Crater, Mars

“…Terrestrial geochemical reference values from the literature were gathered for soil weathering profiles and fluvial sediments in basaltic terrains (Caner et al., 2014; Craig & Loughnan, 1964; De Carlo et al., 2005; Gibson et al., 1983; Ma et al., 2007; H. W. Nesbitt & Wilson, 1992; Pokrovsky et al., 2005; Porder et al., 2007; Rasmussen et al., 2010; Yesavage et al., 2015), all of which are detailed in supplementary text and Table . Data sets from the literature were selected based on the availability of geochemical data coupled with well‐documented information on the climate of each particular study site and with the goal of spanning a significant climatic range.…”