Ferrobustamite-bearing magnetite skarn in marble at Sokolí near Třebíč (Moldanubian zone, Western Moravia)Article PDF
Ferrobustamite-bearing magnetite skarn in marble at Sokolí near Třebíč (Moldanubian zone, Western Moravia)
Ferrobustamite was found in Fe-skarn at Sokolí and it is the first known occurrence in the Bohemian Massif. The skarn forms layer in marble enclosed in leucocratic migmatites (diatexites). Ferrobustamite (Ca4.58–4.70 Mn0.14–0.20 Mg0.01–0.13)5 Fe0.95–1.6 Si5.86–6.01 O18) forms microscopic needle-like aggregates with hedenbergite (Hd71–99) filling intergranulars of grossular-andradite. It forms a massive skarn (endoskarn) whereas exoskarn is composed of andradite + hedenbergite + abundant magnetite with microscopic inclusions of gahnite. The adjacent calcite marble is very poor in flogopite, diopside, and rare hydroxylchondrodite. Marble locally contains veins of diopside, prehnitized anorthite and wollastonite. The mineral assemblage of ferrobustamite is a product of HT/LP-MP metamorphism (skarnization) at T > 600 ° C in the contact aureole of the Třebíč pluton (Moldanubian Zone).
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic, e-mail: email@example.com
Vladimír Šrein, Czech Geological Survey, Klárov 131/3, 118 00 Praha, Czech Republic