Mössbauerite ; polytypes in Tatkul Lake (Russia) marls and evidence in a Murray River reservoir (Australia)

Mössbauer spectroscopy characterizes “Green rust related minerals” of the fougèrite group within the hydrotalcite supergroup (Mills et al. Mineral. Mag. 76 (5), 1289–1336, 2012 ) in locations on Earth quite different from the original studies done in a temperate climate such as Brittany- France, Western Europe. Two examples are described, the gley at the bottom of Tatkul Lake in South Urals (Russia), which is representative of permafrost conditions, and a gley at the bottom of Yanga Lake, a reservoir in the Murray River catchment (NSW-Australia), which is representative of warm and desert conditions. Complementary information is obtained from XRD patterns.