Weathering on icy terrestrial volcanos may tell about weathering on Mars

figure-1[Editor’s note: From a paper by Alicia Rutledge and five co-authors recently published in Geophysical Research Letters].

Silica Dissolution and Precipitation in Glaciated Volcanic Environments and Implications for Mars

• Chemical alteration of glaciated volcanic bedrock is dominated by silica dissolution and precipitation
• Dissolved silica in glacial meltwater is greater at more mafic study sites and results in deposition of opaline silica rock coatings
• Past glacial chemical weathering may be responsible for some amorphous silica deposits on the highly mafic surface of Mars

The planet Mars has glaciers and ice sheets on its surface and probably did in the past. Minerals on the planet’s surface form in the presence of water, but it is unclear which minerals may have formed due to liquid water under warm climates versus those formed under much colder climates.

In order to study this problem, we collected rocks and water from Mars‐like analog sites: glaciated volcanoes. We measured the chemistry of the water and the mineralogy and chemistry of rock coatings found near the glaciers. Both the water and the rock coatings were high in silica.

We propose that glaciers alter volcanic bedrock by dissolving and precipitating noncrystalline silica. Silica detected on the surface of Mars could have formed due to similar processes. [More at link]

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