Commune: Paszowice (pow. jaworski, woj. dolnośląskie)
Framework element or context represented:
Early Palaeozoic submarine volcanism and its subsequent metamorphosis, drainage pattern changes associated with continental glaciation.
Primary geological/geomorphological interest:
Extensive exposures of Early Palaeozoic greenstone, well-developed pillow lava structures, a gorge cut by meltwater.
Comparative assessment justification:
Exceptionally extensive and continuous outcrops of Early Palaeozoic greenstones in its two main structural variants (massive and pillow lava); the best example of a young river valley in the Sudets Mountains. Landforms of similar origin are quite rare in the marginal zone of Scandinavian glaciation in Central Europe.
Protection status and accessibility:
The middle part of the gorge is within nature reserve "Wąwóz Myśłiborski" (9.6 ha), established in 1962 to protect a rare species of fern. The entire gorge is located within the "Chełmy" Landscape Park. An educational trail runs through the gorge.
Character of site: Outcrops in the river gorge.
Area: 170 ha
Altitude: 290-370 m a.s.l.
Lithology: other metamorphic rocks
Discipline: Geomorphology, Petrography
Process Age: Pleistocene, *all periods
Bedrock Age: Ordovician, Cambrian, *all periods
Description of primary interest:
The Myślibórz Gorge is a deeply incised stretch of the Jawornik creek, in the eastern part of the Kaczawa Upland, closed to the mountain front related to the Sudetic Marginal Fault. The gorge follows a sinuous path, is 2.5 km long and 50-80 m deep. Greenstone outcrops within valley sides attain 30 m high and form walls, rocky spurs and semi-isolated towers; beneath them there occur boulder accumulations due to massive slope failures and scree aprons. The channel is locally cut in greenstone bedrock. Greenstones represent products of submarine alkaline volcanism of Early Palaeozoic age, subsequently metamorphosed and deformed; within the gorge they are developed mainly in its massive variant. Pillow lava structures, with individual pillows up to 60 cm long, may be seen on a number of outcrops in the lower part of the gorge. Leaching of calcium from greenstones has resulted in minor tufa (travertine) accumulation at the foot of certain greenstone walls. The origin of the gorge appears related to drainage pattern changes induced by the Scandinavian ice-sheet in the Pleistocene. The gorge is a meltwater channel formed within an upland surface because of blockage of an old valley by dead ice, progressively deepened to adjust to the local base level. The abandoned valley filled by glacial sediments occurs on the upland surface, south of the Myślibórz Gorge.
Literature:
MIGOŃ P. 1999–Gorge-like valleys in the Chełm Landscape Park (English sum.). Chrońmy Przyr. Ojcz. 55(2): 91-99. MIGOŃ P. 2000–Geneza Wąwozu Myśliborskiego na Pogórzu Kaczawskim (Polish only). Przyroda Sudetów Zachodnich 3: 137-144. SYNOWIEC G., JASIŃSKA M. 2002–Rumowiska skalne w dolinach jarowych na Pogórzu Kaczawskim (Polish only). Przyroda Sudetów Zachodnich 5: 175-184.