An experimental study of SO2 reactions with silicate glasses and supercooled melts in the system anorthite–diopside–albite at high temperature

Implications of Reactions Between SO2 and Basaltic Glasses for the Mineralogy of Planetary Crusts

“…The textures of the coatings on the SO 2 ‐reacted reduced (~NNO−5) alkali basalt are similar to the fine‐grained texture observed on the Fe‐free basaltic glass, but with additional fine‐grained glauberite and rounded hematite and magnetite crystals up to 20 μm in diameter. The sulfates are generally fine grained and the coating can be wrinkled and buckled in areas where the coating is thickest, due to lateral expansion of the coating (Renggli et al, ; Renggli & King, ).…”

“…They suggest that the Ca‐availability in the glass drives the sulfate‐forming reaction. Renggli et al () studied dry, pure SO 2 reactions with anorthite‐diopside (AnDi) composition glass starting materials and found a temperature dependence of the reaction products. At 600 °C (below the glass transition temperature, T g ), CaSO 4 and MgSO 4 coatings formed on the An 15 Di 85 , An 36 Di 64 (eutectic glass), and An 48 Di 52 glasses.…”

“…At 600 °C (below the glass transition temperature, T g ), CaSO 4 and MgSO 4 coatings formed on the An 15 Di 85 , An 36 Di 64 (eutectic glass), and An 48 Di 52 glasses. At 800 °C, only CaSO 4 formed on all glasses (Renggli et al, ). In the presence of Ca in the glass, even at concentrations as low as 5 mol.…”

“…%, CaSO 4 is the dominant reaction product on glasses in the anorthite‐diopside‐albite system (Renggli et al, ). Ayris et al () and Renggli et al () both show that the mobility of the sulfate‐forming cation (e.g., Ca 2+ ) in the glass and its diffusion to the glass surface is the rate‐limiting step in the reaction of SO 2 with glass starting material. These studies show that glass composition and structure are important controls for the reaction rate and sulfate compositions.…”

“…In sum, the experimental work shows that sulfur dioxide (gas) rapidly reacts with geologic materials via surface‐mediated reactions, where SO 2 disproportionates to form sulfates and reduced sulfur (gas or sulfides; Burnham, ; Ayris et al, ; Henley et al, , ; Delmelle et al, ; King et al, ; Palm et al, ; Renggli & King, ; Zolotov, ; Renggli et al, ). The reaction follows the following form: where M refers to a cation such as an alkali or alkaline earth cation (e.g., Ca 2+ , Mg 2+ , Na + ).…”