Maleč - Čertova kovadlina
General Characteristics
County (administration):
Jihočeský kraj, Plzeňský kraj
District (town):
Strakonice, Klatovy
Village:
Drážov, Nová Ves, Strašín
Cadastre:
Lhota pod Kůstrým, Zálesí u Drážova, Maleč
Map sheets:
22-34 Vimperk, 22-341 Vacov
Accessibility:
passable footpath
ID:
4233
Geology
Short characteristics of the site:
"Near the solitude of Růždí in the valley of the Růžďský brook, you can come across a huge monolith, the shape of which resembles a blacksmith's anvil. According to legend, the giants from the Giant Castle forged it. ”So many quotes from the portal www.mapy.cz. The mentioned monolith is a part of outcrops and free blocks of syenite porphyry. Massive log cabins and blocks are up to 5 m large and intrude in a length of about 60 m, their outcrops form a rocky threshold in the creek, 100 m below which is the old mill Růždí, there is a well near it. From the road to Maleč, a green tourist sign leads here from the solitude of U Biskupa, which continues through the forest to the settlement of U Benedy, where the asphalt road continues from Kváskovice. The blocks are at the point where a 20–30 m thick vein of syenite porphyry runs in the direction of 80 °, which pierces the discordantly foliated biotite orthogneiss. Very massive and tough rock is randomly oriented. Porphyry is atypical, darker than the usual type with a fine-grained base and with irregularly interspersed sporadic phenocrysts of potassium feldspar up to 1 cm, phlogopite accumulations reach 4 mm. The cracking is sparse into large blocks, one of which forms said anvil. The rock composition is K-feldspar 35%, plagioclase 30% phlogopite 20%, pseudomorphisms after ortopyroxene and / or olivine 10%, clinopyroxene 2%. As an accessory, long prismatic apatite and zircon are very abundant, ilmenite is rare, xenomorphic pyrite is abundant, rarely with the inclusion of chalcopyrite. Secondary is actinolite, serpentine minerals and fine-grained talc. K-feldspar forms idiomorphic growths up to 5 mm, and is also in the matrix together with plagioclase. Gamma spectrometrically determined contents of natural radioactive elements, especially uranium, are high (average of 2 measurements): K = 4.9%, eU = 17.5 ppm, eTh = 33.7 ppm, magnetic susceptibility varies in the range of 0.18–0,24 x 10-3.
Regional geologic unit:
Bohemian Massif > Moldanubicum > Magmatites in Moldanubicum
Stratigraphy:
Devonian - Permian
Subject:
geology, geomorphology, petrology
Geological phenomenon:
characteristic rock, rock plate, frost cliff
Genesis:
magmatic
Rock:
porphyry
Territorial protection
Level of protection:
Registered interesting geological localities
Conflicts of interests:
without conflicts
References
- Žáček, V. et al. (2021): Vysvětlivky k základní geologické mapě České republiky 22-341, list Vacov. - Archiv České geologické služby, Praha.
Elaboration and Updating
Elaborated by:
Vladimír Žáček, 20.01.2021
Updated by:
Citation
The database Important geological localities of the Czech Republic: 4233 [online]. Prague: Czech Geological Survey, 1998 [cit. 2023-06-16]. Available from: https:// lokality.geology.cz/4233.
Location in map:
Assessment
Scientifical assesment:
medium
Educational assesment:
middle
Significance:
regional
Representativeness:
major
Geological importance:
geo-regional value (mapping), geoturistic value
Excursion locality:
yes
Locality conditions:
no problems
You can send information about a change in the status of the site to lokality@geology.cz
