SOIL COVER OF PŘEDNÍ KOBYLA SITE (BOHEMIAN KARST) GENESIS: ROLE OF CLAY MINERALS

A. Žigová¹ and M. Šťastný²

¹ Institute of Geology Academy of Sciences of the Czech Republic, Rozvojová 135, 165 02 Praha 6 - Lysolaje, Czech Republic; e-mail zigova@gli.cas.cz

² Institute of  Rock Structure and Mechanics Academy of Sciences of the Czech Republic, V Holešovičkách 41, Praha 8 - Libeň, Czech Republic; e- mail stastny@alpha.irms.cas.cz

Key words: clay minerals, terra fusca, micromorphology, pedogenesis

Abstract

Soil cover of  Pøední Kobyla site (Bohemian Karst) is represented by relict soils, which  considerably differ from Holocene soils. Relict soils are overlaid by Konìprusy limestones of the Pragian, Early Devonian age. Pøední Kobyla site is covered by illimerized brown earthified terra fusca with slight signs of pseudogleization. This relict soil has a polygenetic character. Fractions < 0.01 mm and  < 0.001 mm from the soil profile are characterized mainly by kaolinite, illite and quartz.  Stage and distribution of plagioclase and feldspar in soil  reflect the strong weathering process. In association with clay minerals kaolinite is dominant.