Mineralogical and Geochemical Implications of Weathering Processes Responsible for Soil Generation in Manaila Alpine Area (Tulghes 3 Unit-Eastern Carpathians)

In the Manaila alpine area, the soil layer developed in situ on top of the sericite-schists, which belong to the Tulghes 3 metamorphic unit. The aim of the present work was to determine the degree of soil formation using both mineralogical and geochemical exploration methods. XRD, FTIR and SEM-EDS results showed that the soil constituents were dioctahedral 2:1 minerals, quartz, chlorite, Na-feldspar, rutire and ilmenite. Mainly illite and secondarily mixed-layer minerals were considered to be the most likely minerals resulting from the transformation of sericite and chlorite under acidic alpine conditions. Geochemical modeling inferred the dominance of illite and the presence of smectite as a chlorite alteration product. The weathering indices supported the moderate stage of the soil development agreeing with mineralogical observations. Because of the abundance of sericite and quartz in the parent material, the soil formation was retarded, and its present composition is still related to the bedrocks.

Automated summary

This study aimed to determine the degree of soil formation in the Manaila alpine area using mineralogical and geochemical exploration methods. The results showed that the soil mainly consists of dioctahedral 2:1 minerals, quartz, chlorite, and other minerals, indicating the influence of sericite and quartz on soil formation.