LIMONITOVÁ MINERALIZACE V NĚMČICKÉM KRASU
Roč.17,č.1-2(2010)
Limonite occurrences are hosted by the Devonian limestones belonging to Němčice-Vratíkov belt. This belt can by interpreted as NNW–SSE trending tectonic slice between the granodiorites Brno massif and Lower Carboniferous Culm sediments. Mineralization is localized along faults in limestone and filling small caves belonging to the Němčice Karst. According to mineralogical and textural features are studied ores interpreted as product of limestones interaction with acid solutions generated during weathering of pyrite-rich Creatacerous sediments. Two main stages evolution can be recognized. During first stage circulate iron rich solutions along pre-existing narrow fractures and faults. Under reduction conditions crystallize pyrite and replaced of the host rock and fossils. During second oxidation stage was empty caves partially filling by limonite sometimes with small intercalations clastic sediments. During this stage limonite ore was partial silicificated and calcificated.
Devonian limestones; limonite mineralization; metasomatism; fractures; faults
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