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Třetihorní subtropy

Počerny Sunstones

In the western surroundings of Karlovy Vary the thickness of sedimentary filling of Sokolov basin is reduced. Thanks to tectonic movements at the end of tertiary and subsequent erosion, rock units of various ages have come close to each other. Thus, in a very little area may occur kaolinized granites, sediments of the basal Staré Sedlo formation, brown coal of Josef layers and volcanic deposits of the Nové Sedlo Formation.

In surroundings of Počerny (now being a part of Karlovy Vary agglomeration) all these geological units are represented. In birch groves southeast of the village the quartzite boulders (so-called sluňáky, “sun stones”) attract attention, a place, which gathered farmers from surrounding fields and meadows. In relatively natural position the “sun stones” can be studied in the forest stand “Na Špici” between railway and gardener's as­sembly. The forest belongs to the estates of village Jenišov.

The (ortho)quartzites formed in warm and moist (humid) climate in the beginning of tertiary, when the kaolinic weathering of substratum granite liberated silica (silicon dioxide). The silica impregnated porous sand and gravel layers up to so-called amorphous quartzites. Later the less resistant surroundings sediments were eroded and so the quartzite domains disintegrated into irregular blocks, which have been smoothed to their present forms by weathering processes. Big quartzite boulders are literally hard nut to crack for building companies, because it is virtually impossible to disjoint them without shot firing. They are driven away en bloc, or left in place as an interesting natural decoration. Searching “sun quartz” at Počerny, you will likely meet irregular funnel depressions and small water surfaces. It concerns remnants after mining of brown coal.

GPS position

N 50° 13.910', E 12° 48.773'