Pedogenetic characteristics of fossil soils in the loess sequence of "Červený kopec" near Brno (Czechoslovakia)

Abstract

Article in German.

ORIGINAL TITLE: Pedogenetische Charakteristik der Fossilböden in der Lößschichtenfolge »Červený kopec« bei Brno (Tschechoslowakei)

In the South Moravian region, loess sediments form thick covers that contain fossil soils exhibiting periglacial features. The well-known site of "Červený kopec" on the southern edge of the city of Brno was studied.

The entire sequence of Pleistocene deposits was divided into four main series. Assuming that the first (youngest) series corresponds approximately to the Würm glaciation, the second series can be attributed to the Riss, the third to the Mindel, and the fourth likely represents the Günz along with other, older sediments. The individual series are further subdivided into distinct soil complexes, provisionally assigned to major interglacial periods.

Each of the aforementioned Pleistocene series consists of layers of loess and fossil soils that correspond to sedimentary cycles. The pedogenetic-sedimentary cycles are consistently represented by a loess cover and fossil soils, which allow for differentiation between the series. The first series generally contains brown soils; the second – chernozems, brown and leached podzolic soils; the third – brown, reddish-brown, and leached podzols; and the fourth – predominantly reddish-brown soils.

The first series comprises approximately four main cycles, the second – seven, the third – five, and the fourth – about two principal cycles.

The individual Pleistocene series, representing a characteristic rhythm of loess sedimentation interrupted by soil formation, support the hypothesis of cyclic development: loess – soil(s) (sedimentation – pedogenesis).

Pedogenetic processes acting upon the loess substrate have led to changes in granulometric composition. Fossil soils are characterised by an increase in fine clay particles and a decrease in the content of silt-sized material (0.01–0.05 mm).

The clay content increases in soils from older series, indicating that pedogenetic processes and weathering were more intense during the Lower Pleistocene.

The Pleistocene sedimentary succession at Červený kopec offers an opportunity for lithological assessment and, consequently, also for palaeoclimatic interpretation. The individual series within this succession represent clearly distinguishable lithological “complexes” corresponding to palaeoclimatic “complexes”.