Zarys badań prekambru górnego w Polsce

Abstract

Prekambr górny, a właściwie jego najwyższą część – wend spoczywający na ryfeju, opracowano głównie na podstawie materiałów z wierceń na platformie prekambryjskiej. W innych obszarach Polski stwierdzono różnorodne utwory osadowe pod kambrem, które zalicza się do prekambru górnego, ale ich stratygrafia nie jest zadowalająco ustalona i wymaga gruntownych badań. A BRIEF OUTLINE OF STUDIES ON THE UPPER PRECAMBRIAN OF POLAND By the Upper Precambrian should be understood sedimentary and tuffogenic-intrusive rocks older than the Cambrian and resting on crystalline basement. Among them there are some untaltered or weakly diagenesed as well as only slightly metamorphosed rocks. Stratigraphic position of these rocks is often debatable as it is not based on any firm evidence.In Poland, Jan Samsonowicz has been the first to introduce the concept of the Riphean for sedimentary Upper Precambrian in the Holy Cross Mts, correlating the Riphean with the Sinian system. The uppermost Upper Precambrian, occurring above the Riphean, is nowadays termed as the Vendian.The Vendian is biparite: its lower part (Volhynian) is tuffogenic-intrusive, and the upper (Valdaian) – sandy-siltstone-clay. In the Lublin area, there is a continuity between upper part of the Vendian and the Lower Cambrian.Beyond the Precambrian Platform, Upper Precambrian rocks are poorly known as they are difficult to reach by drillings and reliable microfloristic and radiometric and other data are still missing. The problem of the Cambrian-Precambrian junction beds is discussed in the monograph prepared by the Polish-Soviet working group (Geological Institute, Warsaw University and Academy of Sciences of the USSR), the successive volumes of which are being published now.