The oldest volcanic activity in the Geopark territory preceded the Paleozoic Era, being dated to the very end of the Precambrian. Granite and diorite were emplaced in the upper crust during the Cadomian Orogeny, constituting relatively extensive bodies. 

These rocks were, however, uplifted again by subsequent geological processes within the Variscan Orogeny. They were metamorphosed into their present-day form: into muscovitic metagranites and metadiorites. The end of the Paleozoic, especially the Permian, was marked by intensive volcanic activity, most notably in the eastern park of the Geopark. Variscan Orogeny, which affected almost all continents of that time, produced a vast mountain range in our territory. The present Krkonoše Mountains, for example, can be viewed as its relict. In this area, orogenic processes were accompanied by effusions of basaltic magma. Basaltic lavas were issued onto the surface or ejected from craters during eruptions, covering their surroundings with thick deposits of tuffs, volcanic bombs and accretionary lapilli. Vugs in solidifying volatile-rich lavas locally became the sites of secondary origin of precious stones.

Created 18.2.2020 14:49:41 - updated 28.2.2020 22:34:44 | read 3125x | sprokesova
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