Podstawy morfostratygrafii czwartorzędu Niżu Polskiego

Abstract

Dzięki analizie geomorfologicznej i paleogeomorfologicznej Niżu Polskiego w czwartorzędzie możemy wydzielać cztery główne typy jednostek morfostratygraficznych (I - kompleksy, II - stadia, III - fazy, IV - etapy) właściwe okresom glacjalnym i interglacjalnym. Jednostki te w dużym stopniu nawiązują do jednostek klimatostratygraficznego podziału plejstocenu S.Z. Różyckiego oraz dają możliwość korelacji stratygraficznych i odtwarzania ewolucji paleogeograficznej obszaru Polski w czwartorzędzie.PRINCIPLES OF MORPHOSTRATIGRAPHY OF THE QUATERNARY IN THE POLISH LOWLAND The geomorphological and paleogeomorphological analysis is one of methods for establishing stratigraphy or the Quaternary, especially Pleistocene in a given area. The analysis involves compilation or characteristics of morphometric, morphogenetic and morphochronologic forms and types of relief (M. Klimaszewski, 1978) and subsequently, attempt to reconstruct paleogeomorphological setting of the studied area by both mapping methods and correlation of borehole data (Figs. 1-5). The use of geomorphological and paleogeomorphological analysis makes possible differentiation of morphostratigraphic units of the orders I - IV (l – complexes, II - stadiaIs, III – phases, and lV - subphases). The units appear very close to the climatostratigraphic ones from the subdivision proposed for the Pleistocene by S.Z. Różycki (1964a). Differentiation of the first-order units - complexes (glacials and interglacials) - is connected with identification and analysis of relief of modem and ancient morainic plateaux and reconstruction of fossil interglacial surfaces with reference to the principle of similarity of ancient landscapes (especially in development of interglacial river valleys) to the modern. When this is accomplished, it becomes possible to differentiate second-order morphostratigraphic units (11 - stadials) and assign them to a given morphostratigraphic complex. The second-order units - stadials - are related to changes in position of icesheet front at distance over 100 km, and those of the third order (phases) - disappearance or transgression of icesheet at distance from 20 to 50 km. An existence of major (stadials) or minor (phases) trends 10 organization of river network may be used as the major criterion in identification of forms and types used in assignation of both modem and ancient river relief to units of the second order (stadials). In turn, differentiation of units of the fourth order (subphases) will be possible mainly on the basis of analysis of the present-day relief. In the case of morainic plateaux, the units are mainly characterized by relief which reflects events of rapid disappearance of icesheet, broken by those of relative equilibrium of ablation processes and fresh supply of ice from area situated directly behind the frontal zone, and in the case of river valleys - by development of meander systems on individual terrace surfaces.