Paleozoic deposits of various characters can be found especially in the northern and eastern parts of the Geopark. Thick successions of phyllites (so-called roofing slates) can be found in the area of Železný Brod. They pertain to the Krkonoše–Jizera Crystalline Complex and are usually greyish-green or purplish in colour.

These phyllites were originally deep-sea sediments (claystones, siltstones) in Ordovician times, later subjected to weak metamorphism. In spite of this, they preserve many trace fossils, and rarely body fossils too, which allow to determine the age of the rock.
In the late Paleozoic (Carboniferous and Permian), the waning Variscan Orogeny contributed to the formation of a number of basins in the Krkonoše piedmont region. Their deposits now cover mainly the area around Nová Paka. These lacustrine and fluvial sediments range from coarse conglomerates and arkoses across sandstones and siltstones to the finest claystones. They are often orange or brownish-red, which is a typical colour of rocks of this age in the Geopark territory. In places, they are complemented with beds of volcanosedimentary rocks, such as tuffites. They contain abundant fossil remains of flora and fauna of that time.

Created 18.2.2020 14:50:52 - updated 28.2.2020 22:38:38 | read 1314x | sprokesova
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