Granica jury środkowej i górnej na obszarze północnej Lubelszczyzny i Podlasia

Abstract

BOUNDARY OF THE MIDDLE AND UPPER JURASSIC IN THE NORTHERN AREA OF THE LUBLIN REGION AND IN THE PODLASIE REGIONTwo various lithological complexes, cinoidal and syphozoan, occur in the profiles of the Jurassic deposits at the boundary of Callovian and Oxfordian, within the northern area of the Lublin region and in·the Podlasie region (Fig. 2).The crinoidal complex consists of crinoid fauna detritus and subordinately of lamellibranch, brachiopod and coral detritus. The complex is characterized by the occurrence of iron hydroxide that impregnates the rock and gives a rusty colour to it. The complex occurs in the shape of concretions and of iron crusts. Quartz grains and intercalations of dolomite rooks are abundant. The complex is documented by the ammonite and brachiopod fauna found as·single forms in several bore holes. The following forms may be mentioned here: Kosmoceras ornatum (Magnuszew), Kallirhynchia sp. (Ciepielów), Thurmanella thurmani (Łuków). At the top of this complex a nodular bed of Callovian age has been found in bore hole Warszawa, with the following forms: Hecticoceras punctatum, Hecticoceras sp. ex gr. punctatum, Kosmoceras cf. jason, Kosmoceras cf. medea, Kosmoceras cf. castor var. bireti, Kosmoceras sp., Reineckeia sp. Peltoceras sp., and Ammonites .sp. ind. (Reineckeia sp.), Peltoceras sp., Ammonites sp.