Iron oxidation state of impact glasses from the Zhamanshin crater studied by X-ray absorption spectroscopy

Highlights: • Irghizite samples have the lowest oxidation state of 2.2 +. • Silica-poor zhamanshinite sample has the highest oxidation state of 2.8 +. • Average coordination number for irghizites is ~ 4.8. • Average coordination number for silica-rich zhamanshinite is ~ 4.8. • Average coordination number for silica-poor zhamanshinites is ~ 5.5. - Abstract: X-ray absorption spectroscopy (XAS) has been used to analyze the change in iron oxidation state and coordination numbers of impact glasses from the Zhamanshin crater. Series of samples, specifically aerodynamically shaped small glassy bodies – irghizites, and silica-rich and silica-poor glasses – zhamanshinites, have been investigated. The Fe^2.2+ oxidation state was determined for the irghizites and the highest value Fe^2.8+ for the silica-poor zhamanshinite. These values agree with the trend of oxidation processes upon high speed interaction of meteorite parent body and target rocks. The obtained data can be used for future establishment of the formation parameters (P, T, f_O2 conditions) of these impact glasses as well as relationships between the rocks.