Commune: Barcin (pow. żniński, woj. kujawsko-pomorskie)
Framework element or context represented:
Shallow-marine facies and ubiquitous fossils.
Primary geological/geomorphological interest:
Fossiliferous biohermal complex of Upper Jurassic age.
Comparative assessment justification:
Wide spectrum of diverse facies of the complex structure, from the bioherm core, through slopes moving down into basin depths.
Protection status and accessibility:
Protection proposed, accessibility due to quarry permission.
Character of site: Abandoned parts of the quarry.
Area: 10 ha
Altitude: 69-90 m a.s.l.
Lithology: other evaporite rocks, other organic rocks
Discipline: Palaeobiology, Palaeoenvironment, Stratigraphy of Phanerozoic
Process Age: *all periods
Bedrock Age: Jurassic, *all periods
Description of primary interest:
The Middle to Late Jurassic (uppermost Oxfordian) sequence of a cyanobacterial-sponge buildup and its flanks diverging into muddy basin facies has developed atop salt-domed (halokinetic) anticline rising along the Mid-Polish Anticlinorium, in the Kujawy (Couiavia) region of north-Central Poland. The two huge quarries, Bielawy and Wapienno, over 1 km long and over 100 m deep, make easy access to particular facies of this carbonate buildup, some of which yield ubiquitous fossils of various types (sponges, polychaetes, brachiopods, ammonites, crinoids, and echinoids). Sedimentary features and eco-taphonomy of diverse biota indicate the complex structure of the buildup having been raised simultaneously with upheaval of a salt diapire in the basement. Easy insight into ancient reef-like biohermal complex.
Literature:
COLLINS J.S.H. & WIERZBOWSKI A. 1985–Crabs from the Oxfordian sponge megafacies of Poland. Acta Geol. Pol. 35 (1/2): 73-88. GALLINEK E. 1896–Der Obere Jura bei Inowrazlaw in Posen. Verhandlungen der Kaiserlichen Russischen Mineralogischen Gesell. St. Petersburg 33 (2): 353-427. JAEKEL O. 1892–Ueber Plicatocriniden, Hyocrinus und Saccocoma. Zeit. der Deuts. Geolog. Gesell. 44: 619-696. MATYJA B.A. & WIERZBOWSKI A. 2000–Biostratigraphical correlations between the Subboreal Mutabilis Zone and the Submediterranean Upper Hypselocyclum-Divisum Zone of the Kimmeridgian: new data from northern Poland. GeoResearch Forum 6: 129-136. MATYJA B.A. & WIERZBOWSKI A. 2002–Boreal and Subboreal ammonites in the Submediterranean uppermost Oxfordian in the Bielawy section (northern Poland) and their correlation value. Acta Geol. Pol. 52 (4): 411-421. RADWAŃSKA U. 2003–A monograph of the Polish Oxfordian echinoids; Part 1, Subclass Cidaroidea CLAUS, 1880. Acta Geol. Pol. 53 (2): 141-165. RADWAŃSKA U. 2003–Aberrant starfish of the genus Sphaeraster QUENSTEDT, 1875, from the Oxfordian sequence of Wapienno/Bielawy (Couiavia region, Poland). Tomy Jurajskie 1: 63-69. RADWAŃSKA U. 2004–Tube-dwelling polychaetes from the Upper Oxfordian of Wapienno/Bielawy, Couiavia region, north-central Poland. Acta Geol. Pol. 54 (1): 35-52. RADWAŃSKA U. & RADWAŃSKI A. 2003–The Jurassic crinoid genus Cyclocrinus D'Orbigny, 1850: still an enigma. Acta Geol. Pol. 53 (4): 301-319.