Zastosowanie metod petrograficznych do klasyfikacji genetycznej osadów czwartorzędowych na wybranym przykładzie
Abstract
APPLICATION OF PETROGRAPHIC METHODS IN GENETIC CLASSIFICATION OF QUATERNARY DEPOSITS; SOME EXAMPLES
Summary
Samples of Quaternary deposits from drillings and excavations made in the area of Mała Panew valley in the upper Silesia were analysed. The results of petrographic analyses of gravels of the 2-5 mm and 5-10 mm fractions and heavy minerals of the 0.1- 0.25 mm fraction are plotted on classification triangles illustrating degree of weathering. The former are plotted on the triangles fraction (Figs. 2 and 3 for the 2-5 mm and 5--10 mm fractions, respectively) with peaks representing the sum of: K - quartz, Kr - crystalline rocks, and O – sedimentary rocks. The latter are plotted on the triangle (Fig. 1) with peaks representing the sum of: T - persistent, ST - semipersistent, and N - impersistent minerals. The tills representing the Mid-Polish and Cracow Glaciations appear to be markedly similar in petrographic composition, markedly differing from Eopleistocene deposits. Samples taken from excavations are strongly weathered, similarly as the tills of the Mid-Polish Glaciation sampled on even fairly large depths. This evidences intensity of interglacial and periglacial weathering. Arrows on the Figures 2-3 indicate location of samples of solifluction loams in relation to samples of tills derived from the same borehole. According to the present author the method discussed here makes it possible to discriminate tills and fossil solifluction loams taking into account impoverishment of the latter in less resistant components.
Summary
Samples of Quaternary deposits from drillings and excavations made in the area of Mała Panew valley in the upper Silesia were analysed. The results of petrographic analyses of gravels of the 2-5 mm and 5-10 mm fractions and heavy minerals of the 0.1- 0.25 mm fraction are plotted on classification triangles illustrating degree of weathering. The former are plotted on the triangles fraction (Figs. 2 and 3 for the 2-5 mm and 5--10 mm fractions, respectively) with peaks representing the sum of: K - quartz, Kr - crystalline rocks, and O – sedimentary rocks. The latter are plotted on the triangle (Fig. 1) with peaks representing the sum of: T - persistent, ST - semipersistent, and N - impersistent minerals. The tills representing the Mid-Polish and Cracow Glaciations appear to be markedly similar in petrographic composition, markedly differing from Eopleistocene deposits. Samples taken from excavations are strongly weathered, similarly as the tills of the Mid-Polish Glaciation sampled on even fairly large depths. This evidences intensity of interglacial and periglacial weathering. Arrows on the Figures 2-3 indicate location of samples of solifluction loams in relation to samples of tills derived from the same borehole. According to the present author the method discussed here makes it possible to discriminate tills and fossil solifluction loams taking into account impoverishment of the latter in less resistant components.