Microanalytical evidence for short range clay coatings in weathered granodiorite

Abstract

Thin sections of two soils formed in situ derived from granodiorite were examined by scanning electron microscope microprobe analyser to ascertain whether clay coatings in the weathered granodiorite are illuvial or whether they are a short range phenomenon. The clay in the clay coatings of the weathered rock was of markedly different composition from the clay in the soil above. It is concluded that clay was formed from the weathering minerals in the rock and deposited as short range clay coatings within the weathered rock.