Ordowik obszaru Białowieży Mielnika

Abstract

THE ORDOVICIAN IN THE REGIONS OF BIAŁOWIEŻA AND MIELNIKThe paper deals with the Ordovician deposits of the northeastern area of Poland. The extension ,of the investigated geological profile amounts over 90 km. The profile of the Lower and Middle Ordovician is identical with that of the Ordovician in Estonia. Differences are seen only in thicknesses of individual strati-graphic members.Correlation profiles and synthetical profile are shown on Figs. 1 and 12. Fig. 2: shows also a correlation with the Estonian horizons, as well as with the graptolite horizons. Thicknesses of individual stratigraphical horizons are presented on Tab. 1.On the Cambrian deposits (Middle Cambrian?, Upper Cambrian?, beds from Skupowo) rest the lower and upper Obolus sandstones, divided by 'R series of clayey slates. Similarly as at Pakerort, the Obolus sandstones are covered by black clayey graptolite schists which are eroded in places. The Obolus sandstones and graptolite schists represent the Tremadocian deposits (beds from Krzyż). On the graptolite schists, or on the Obolus sandstones, always rests a bed of glauconitite passing, to the top into glauconite limestone. Between the glauconitite and the glauconite limestone a thin bed of variegated graptolites schists occurs. The three members under discussion belong to the Arenig (beds from Białowieża). The glauconite limestones pass into limestones containing very numerous chamoisite oolites which are mostly limonitized. The oolite limestones belong to the Llanvirnian (lower Pomeranian beds). The two uppermost complexes of grey limestones, as well as limestones and marls have been assigned to the Llandeilian and Lower Caradocian (middle Pomeranian beds).All the discussed rock complexes of individual stratigraphical members contain abundant fauna of brachia pods, trilobites, cephalopods and graptolites.