KRA JURAJSKA (KRA JURAJSKA NATURE RESERVE)



Commune: Łuków (pow. łukowski, woj. lubelskie)

Framework element or context represented:
Pleistocene ice-sheet sediments.

Primary geological/geomorphological interest:
Concretions abounding in Jurassic fossils within Pleistocene deposits.

Comparative assessment justification:
The site in Łuków is exceptional due to the occurrence of rich and well preserved fossils. It is valuable for the biostratigraphy of the Middle/Upper Jurassic boundary.

Protection status and accessibility:
Nature reserve was established in 1980. Now the old brickyard in Gołaszyn is flowed and not accessible. Unique specimens of the Łuków fauna are conserved in many museum collections.

Character of site: Abandoned brickyard.

Area: 8 ha

Altitude: 165 m a.s.l.

Lithology: tills, sands, silts, clays

Discipline: Palaeobiology, Stratigraphy of Quaternary

Process Age: *all periods

Bedrock Age: Pleistocene, Jurassic, *all periods




Description of primary interest:
Middle/Upper Jurassic clays had been excavated near the Łuków in the brickyard recently filled with water. In the neighbourhood of them few separated sheets of Jurassic clays up to 28 m thick have been recognised by borings. The brickyard was used a long time especially since the beginning of XX c. The area of Jurassic deposits in the vicinity of Łuków cover about 1 km2. It is situated within moraines and sands of the Middle Polish Glaciation. Clays enclose numerous calcareous and sideritic concretions spherical and spindle-shaped with pyrite and concentrations of shells excellently preserved. Fauna of ammonites is rich and contains in particular Quenstedtoceras, Kosmoceras pollucinum and Oecoptychius refractus (according to H. Makowski). On the base of studies of ammonites the age of clays is estimates as Upper Callovian – Lower Oxfordian. S. Staszic – the Father of Polish Geology knew the fossil fauna from Łuków just in the early XVIII c., and first descriptions of clays are dated to XVIII/XIX c. (N. Krzysztafowicz, A. Rychłowski). Jurassic clays have been primary admitted as deposits in situ then they were recognised as a huge blocks detached from the bedrock. Similar deposits in situ occur below Pleistocene moraines in Lithuania, about 500 km to the north of Łuków. It is the longest way of transportation in the Polish territory where the biggest blocks had been detached from the bedrock and probably in the frozen state were incorporated within glacial sediments of the Middle Polish ice-sheet.

Literature:

GAŁĄZKA D. 2004–Zastosowanie metody mikroskopowego oznaczania eratyków przewodnich do lokalizacji obszarów źródłowych wybranych kier jurajskich (Polish only). Przegląd. Geol. 52, 4: 349-350.     JAHN A. 1950–New facts concerning the ice transported block of the Jurassic at Łuków (English sum.). Rocznik Pol. Tow. Geol. 19, 2: 371-385.     KULICKI C. 1974–Remarks on the embryogeny and post embryonal development of ammonites. Acta Palaeontologica Polonica 19: 201-224.     KULICKI C. 1979–The ammonite shall: its structure, development, and biological significance. Palaeontologia Polonica 39: 97-142.     ŁUNIEWSKI A., ŚWIDZIŃSKI H. 1929–W sprawie kry jurajskiej pod Łukowem (Polish only). Przegląd Geograficzny 9: 160-165.     MAKOWSKI H. 1952–La faune Callovienne de Łuków en Pologne. Palaeontologia Polonica 4.     MIZERSKI W. 1980–Jurajskie kry lodowcowe w okolicy Łukowa (Polish only). Prace Mazowieckiego Ośrodka Bad. Nauk. 51: 397-412.     MIZERSKI W., SZAMAŁEK K. 1985–Geological raw material characteristic of erratic mass Callovian clay rocks from vicinities of Gołaszyn near Łuków (Podlasie region) (English sum.). Kwartalnik Geologiczny 29: 369-392.     MORAWSKI J. 1954–A contribution to the knowledge of Jurassic rock in the environs of Łuków (English sum.). Ann. Univ. M. Curie-Skłodowskiej, B, 9, 1: 1-45.     OLEMPSKA E, BŁASZYK J. 2001–A breal ostracod assemblage from the Callovian of Łuków area, Poland. Acta Palaeontologica Polonica 46, 4: 55-582.     RUSZCZYŃSKA-SZENAJCH H. 1976–Glacitectonic depressions and glacial rafts in Mid-Eastern Poland (English sum.). Studia Geol. Pol. 50: 7-106.