Nowe dane o triasie środkowym na obszarze północno-wschodniej Polski

Abstract

NOVEL DATA ON THE MIDDLE TRIASSIC UPON THE AREA OF NORTHEASTERN POLAND

During the field investigations upon the area of Northeastern Poland, there have been reached, in some of the bore-holes (Magnuszew, Żebrek, Ostrów Mazowiecka,. Płońsk and Ełk), sediments of the Middle Triassic, known from a bore-hole previously put down in this area, at Pisz. By comparing these sediments with the columnar section of the Muschelkalk and the Roth·of the periphery of the Święty Krzyż Mountains it has been ascertained that during the Roth there has been land on the northeastern area of Poland (Fig. 1) as well as upon the region situated north pf the Święty Krzyż Mountains. The sea transgressed upon this land by a narrow bay in the region of bore-hole Żebrak where oolitic deposits were formed. Towards the end of the Lower Muschelkalk, the sea occupied almost all of North-eastern Poland (Fig. 2) and may even have penetrated Lithuanian territory.