Commune:
Framework element or context represented:
Neogene volcanism of the Sudety Mts.
Primary geological/geomorphological interest:
Neogene volcanism, columnar structure within basalt.
Comparative assessment justification:
Neogene volcanic pipe, a number of volcanic phases recognise.
Protection status and accessibility:
Geological reserve Wilcza Mt. established in 1959 as a part of the active quarry of basaltic rock.
Character of site: Artificial outcrop.
Area: 1.69 ha
Altitude: 373 m a.s.l.
Lithology: other igneous rocks, conglomerates, breccias, other sedimentary rocks
Discipline: Petrography, Stratigraphy of Phanerozoic
Process Age: *all periods
Bedrock Age: Neogene, *all periods
Description of primary interest:
The basaltic rocks of the Wilcza Mt. have been extensively mined. The quarries situated on the western and south-western slopes of the mountain allow to observe the internal structure of the volcanic dome. Several remnants of a number of volcanic phases have been recognised. The preliminary phase is represented by the tuffs and volcanic breccia. The outer part of the volcanic pipe consists of the first generation of basaltic lava, a plagioclase and nepheline rich one, characterised by a columnar structure formed by a lava cooling jointing. The columns are leaning 30 degrees against the vertical axis of the volcanic pipe. The second generation of the lava is characterised by thinner columns, orientated randomly and located closer to the centre of the volcanic pipe. Within all types of lavas there have been found numerous xenoliths of sandstones, rhyolites, quartzites and siltstones.
Literature:
BIRKENMAJER K. 1967 — Lower Silesian basalts as monuments of inanimate nature (English sum.). Ochr. Przyr., 32: 225-276. BOBIŃSKI W., GAWLIKOWSKA E., KŁONOWSKI M. 1999 - Important geosites of the Polish Sudetes. Pol. Geol. Inst., Spec. Papers, 2: 19-25. GROCHOLSKI A. & JERZMAŃSKI J. 1975 — Palaeovolcanic occurrence in the Lower Silesia, in the light of nature protection (English sum.). Ochr. Przyr., 40: 291-349. KARDYMOWICZ I. 1967 — Inclusions in some Silesian basalts (English sum.). Biul. Inst. Geol, 197: 451- 483. ŚLIWA Z. 1967 — Structures in Silesian basalts (English sum.). Rocznik PTG, 37: 435-454.