REZERWAT PRZYRODY OSTRZYCA PROBOSZCZOWICKA (OSTRZYCA PROBOSZCZOWICKA NATURE RESERVE) - near Czech borders - village Probosczow
Ostrzyca (501 m a.s.l.) is a residual hill biult of Cenozoic basalt, towering by 150 m above the sourrounding gently rolling landscape cut across Lower Permian sandstone and conglomerates. It assumes a characteristic conical shape with steep slopes up to 40o inclination, therefore the hill is often mistakenly considered as a volcanic cone. Basalt builds the uppermost 60-70 m of the hill and displays well-developed columnar jointing, with individual columns 15-30 cm across. Columns dip in various directions and at various angles, which is reflected in details of slope geomorphology. Rock spurs up to 10 m high form in places where columns dip steeply into the slope, whereas benches occur where the dip is more horizontal. A crag 20 m long occurs in the summit part. Slopes are covered by extensive, largely unvegetated scree aprons supplied by mechanical disintegration of spurs and crags. Scree micromorphology indicates past transport aided by deformation of cementing ice, whereas current gravitational movement is shown by tree trunks being progressively buried by basalt scree.
|REZERWAT PRZYRODY WILCZA GÓRA (WILCZA MT. NATURE RESERVE) - near czech borders, village Zlotoryja|
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, quarzites and siltstones.