Dobrčice, Skršín, Most District, Ústí nad Labem Region, Czech Republici

Regional Level Types
Dobrčice	Village
Skršín	Municipality
Most District	District
Ústí nad Labem Region	Region
Czech Republic	Country

Dobrčice (German: Dobschitz) is a settlement of the village Skršín in the southeastern part of the Most district in the Ústí nad Labem region. It is located at an altitude of 368 meters at the western foot of the hill called Dobský ridge.

Old coal mine with deposits of porcelainite (porcellanite), a semi-metamorphosed chert heated at contact with basalt or, in this case, a burning coal seam.

Analysis of the porcelainites from this mine reveals the following compositions:

Red porcellanite: mullite + tridymite + cordierite, subordinate hematite + Ti-magnetite (ulvöspinel) + K-feldspar.

Grey porcellanite: mainly cordierite + mullite and tridymite + admixture of corundum, subordinate K-feldspar.

Brown scoria: large amount of hematite, substantial amount of calcic plagioclase + cordierite, a lesser amount of mullite + tridymite + REE-rich apatite + orthopyroxene, probably spinel and goethite.

Yellow porcellanite: mostly quartz, tridymite + mullite, subordinate corundum + K-feldspar + calcic plagioclase + ilmenite + anatase or rutile, scarcely REE-rich monazite.

Description of the site:

The Dobrčice porcellanites, derived from sediments of the Overlying Formation above the main Miocene coal seam, are exposed in an erosional block in the eastern part of the basin. They are located on the periphery of the former Mariana open-cast coal mine. The rock, the maximal thickness of which is 15 m, was exploited as aggregate for mine roads and transport trucks. The quarry yielded some 2 million tons of aggregate, was later recultivated, with a wall only 50 m long and 10 m high being exposed today.

This small but instructive remnant lies on the WSW foot of forested Špičák Hill (360 m a.s.l.). The distinct, multi-coloured character of the outcrop attracts attention already from a distance. The gently inclined complex is composed of variegated porcellanite beds with alternating red, orange, yellow, blue, violet, pinkish, brown and grey colours. Most types are compact in hand specimens. Sluggy structure is occasionally developed. Individual colours follow precisely the original bedding of the primary clay-dominated succession dipping approximately 20° W. In places, porcellanite beds are folded due to the loss in volume caused by caustic dehydration. Intensive and irregular jointing is a typical feature of the whole succession. The burning coal seam, the source of the caustic transformational heat, is hidden just below the present base of the quarry.

Fossils

This region is too big or complex to display the fossil list, try looking at smaller subregions.

Other Databases

Wikipedia:	https://cs.wikipedia.org/wiki/Dobr%C4%8Dice_(Skr%C5%A1%C3%ADn)
Wikidata ID:	Q11812904

References