Peraluminous margarite and paragonite of retrograde origin in a staurolite- and corundum-bearing talc-tourmaline-phlogopite-chlorite schist from Mount Bernstein, northern Victoria Land, Antarctica, contain 0.17 and 0.18 wt% Li2O, 0.05 and 0.004% BeO, 0.02 and 0.31% BaO, and 0.26 and 1.3% SrO, respectively, by ion-microprobe analysis (estimated accuracy: ±20%). In addition, only 0.01% F and 0.02–0.03% B2O3 and no Rb were found with the ion microprobe. This is the first report of significant amounts of Li and Sr in paragonite. The unusual compositions of the paragonite and margarite are attributed to their ability to incorporate Li released from breakdown of lithian staurolite and Sr made available during a retrograde metamorphic stage in a silica-undersaturated rock. Their low B2O3 contents are attributed to the inability of the mica structure to accommodate the small, IVB ion in the tetrahedral sheet even in a B-enriched host rock.

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