Petrography and mineralogy of the skarn body near Malešov (Kutná Hora Crystalline Complex, Czech Republic)Article PDF
Petrography and mineralogy of the skarn body near Malešov (Kutná Hora Crystalline Complex, Czech Republic)
The skarn body near Malešov belongs to calcium-iron skarns with a typical Ca-Fe-Al mineral association. The Malešov skarn body is located in the structurally highest part of the Kutná Hora Crystalline Complex, the Malín Unit, which in this part is mainly formed by gneisses and migmatites. The deposit body is dominated by garnet-pyroxene skarn, less frequently by garnet and magnetite skarn. Replacement of primary minerals by amphibole or epidote also occurs. Fine-grained garnet skarn is formed by isotropic dark red garnet (Adr78–88Grs9–19Alm2–4Pyr0–0.3), while massive garnet skarn consists of garnet grains with different core (Adr13–38Grs31–50Alm29–36Pyr0–2.5) and rim (Adr28–66Grs21–37Alm12–33Pyr0–1.6) chemistry. In association with garnet is often pyroxene (Hd60–90Di10–40) which can be replaced by amphibole (hastingsite composition). Other minerals are magnetite, Fe-epidote, calcite and albite. Magnetite is characterized by high content of Al2O3 (0.54 wt. %) a SiO2 (0.1 wt. %), while siderophile (V, Cr) and chalcophile elements (Ni, Cu, Zn) are below the detection limit. From the observed petrographic relationships, garnet, pyroxene, and magnetite skarns appear to be primary, while the formation of amphibole reaction zones, epidote, car bo nate veins, or weak silicification caused by the emplacement of granitic pegmatites, are probably products of late alteration.
Jan Bubal, Museum of The Bohemian Paradise, Turnov, Skálova 71, 511 01 Turnov, Czech Republic, e-mail: email@example.com
David Dolejš, Institute of Earth and Environmental Sciences, Mineralogy – Petrology, Albert-Ludwigs-University of Freiburg, Albertstr. 23b, 79104 Freiburg, Germany