Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 81. (Budapest 1989)

Szendrei, G.: Microscopic study of thin sections from lithogenic soils

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus81. Budapest, 1990 p.5-13. Microscopic study of thin sections from lithogenic soils by G. SZENDREI, Budapest G.SZENDREI: Microscopic study of thin sections from lithogenic soils.-Annlshist, -nat Mus. natn. hung. 1989, 81:5-13. Abstract - A micromorphological study was carried out on four typical uthogenic soils, i.e. humus-carbonate soil, black rendzina, red clayey rendzina and erubase soil (located in Middle and North, North-East Hungary). The observed micromorphological features were compared to those of the soil types discussed earlier in the literature. Furthermore, an interpretation of the investigations from the aspects of soil genesis is given. Introduction - The microscopic examination of thin sections prepared from undisturbed soil samples is the principal method used in soil micromorphology. The method was developed from pétrographie microscopy and still applies many technical details and approaches of evaluation used in mineralogy and petrology in recent days. Concerning the micromorphology of lithogenic soils only few data are available in general and even much less on Hungarian soils (MOROZOVA 1988, SZABÓ 1974, SZABÓ, MÁRTON & PÁRTAY1964) in spite of the fact that soil micromorphology can contribute to a better understanding of the forming processes in the soils under discussion. The common characteristic feature of soils grouped into the main type of lithogenic soils (according to the Hungarian soil classification system) is the close dependence upon the properties of the parent material and the considerable accumulation of humus (Manual 1987, STEFANOVITS 1981). The soil types belonging to the main type of lithogenic soils are as follows (SZABOLCS 1966): humus-carbonate, rendzina, and erubase soil. The three types are different in their parent material, thus humus-carbonate soils can be formed on loose, whereas rendzinas on hard calcareous rocks. Erubase soils originate from rocks (e.g. andésite, basalte and tuffs of equivalent composition) yielding large amount of clays which are mainly of the swelling type. Materials and methods For the micromorphological investigation typical profiles of humus-carbonate soil (Buda Mts.), black rendzina (Buda Mts.), red clayey rendzina (Aggtelek Mts.) and erubase soil (Mátra Mts.) were selected. From each genetic horizon an undisturbed sample was taken. The soil thin sections were prepared by the method detailed previously (SZENDREI 1970, 1980,1988). The soil thin sections were examined under a Leitz-Ortholux polarizing microscope. The micromorphological features of the soils were described according to the terminology of Handbook for Soil Thin Section Description (BULLOCK et al. 1985). Sometimes the terms introduced by BREWER (1964) were also mentioned, because numerous descriptions were and still are presented and many facts and statements were discussed following his terminology.