Fracture carbonates in granites of the Bedřichov water supply tunnel in the Jizera Mts.
Abstract
Open fractures in the Krkonoše-Jizera Composite Massif were healed in the late stage of magma crystallization and consolidation by aplite, lamprophyre and Cenozoic basalt dykes. The youngest fillings of the fractures are quartz-carbonate and carbonate veins and veinlets, often with zoned or brecciate structure. The central parts of veins are often filled with carbonates of ankerite up to rhodochrosite in composition. Calcite belongs among the youngest carbonates and forms individual crystals in quartz vugs. A specific fracture carbonates composition in the vein filling indicates significant differences in paleofluids composition and temperature from which these minerals crystallized.