Aalen i dolny bajos w południowej części Kujaw

Abstract

 THE AALENIAN AND LOWER BAJOCIAN OF THESOUTHERN KUJAWYSummaryThe facial development of Aalenian andLower Bajociandeposits penetrated by deep drillings in the southern Kujawy, and by shallow drillings made in the course of mapping of the area of Justynów structure is analysed in detail. Numerous ammonites found in core material made it possible to date the deposits. The analysis also covered the published descriptions of the sedimentary series from theŁęczyca anticline and the Mesozoic margins of the Świętokrzyskie Mts, penetrated by numerous shallow drillings.The main conclusions drawn from the analysis are as follows:1. Lower Aalenian (Leioceras opalinum Zone), represented by siltstone-sandstone deposits, concordantly overlies the uppermost Liassic whose upper boundary remains unchanged.2. Upper Aalenian (Ludwigia murchisonae Zone) concordantly overlies deposits of the Leioceras opalinum Zone, and it is represented by black clay slates with ammonites, siderite concretions, numerous fragments of crinoid stems and pyritized plant debris.3. The clay slates of the Ludwigia murchisonae Zone are overlayed by black clay-silty shales with small pockets or lumps of light-gray dolomite or dolomitic sandstone. The former were originally regarded as the uppermost Aalenian series but ammonite datings indicate their early Bajocian age (Sonninia sowerbyi – Stephanoceras humphriesianum Zones).4. Sandy series concordantly or penacordantly overlying clay-silty shales of the lower zones of the Lower Bajocian, formerly regarded as representing the whole Lower Bajocian, presumably corresponds to the Teloceras blagdeni Zone. This zone reflects the onset of the regression which attained the maximum in the Strenoceras subfurcatum Zone of theUpper Bajocian (Kuiavian).