M¿ssbauer and thermoluminescence (TL) data have elucidated the terrestrial histories of five equilibrated chondrites, of petrologic types 5 and 6, collected on blue ice fields near Frontier Mountain in Antarctica. M¿ssbauer spectroscopy substantially reflects the destruction of iron-bearing species with formation of finely divided aggregates of iron oxides or oxyhydroxides. TL sensitivity reflects the possible coating of the feldspar grains due to the iron oxide mobility during progressive weathering. ¿ 1999 American Geophysical Union