Origin, distribution and transformation of authigenic carbonates in loessic soils

• Main Authors: Martin Kolesár, Ján Čurlik
• Format: Article
• Language: English
• Published: Federation of Eurasian Soil Science Societies 2015-01-01
• Series: Eurasian Journal of Soil Science
• Subjects: Authigenic carbonates; oxalate-carbonate pathway; needle shaped calcites; micritic calcites; loessic soils; micromorphological aspects
• Online Access: http://dergipark.ulakbim.gov.tr/ejss/article/view/5000086122/5000080151

Processes of authigenic carbonates formation are component part of terrestrial biogeochemical cycle of carbon, which starts with co-accumulation of oxalic acid and Ca in Ca- oxalates. After plant decay are these biominerals slowly transformed under the influence of microbial processes into authigenic carbonates (calcites), depending on soil condition. The formation of authigenic calcites runs over in soil system where is rather high Ca and Mg concentration, presence of oxalomorphic plants and sufficient oxalotrophic stability of microorganisms. In addition to Ca-oxalates, Ca and Mg ions necessary for carbonate formation comes also from air (precipitation, dust), mineral weathering, subsurface water flow and decaying organic matter. The distribution pattern of authigenic calcites with depth, the size and shape of individual forms of calcites on loessic soils of SW Slovakia, as it is resulted from micromorphological study indicate that through the historical development of that soils as landscape units, soil water regime has played decisive role at vertical redistribution of forms (size, shape) of authigenic calcites. To this witness the depth of variation of needle calcite zones and horizons of micritic calcites occurrence depending on soil types (leaching). Needle shape calcite zones which approach closest to the soil surface, gradually coalescence to the horizons of micritic calcites with the depth. Micritic calcites are without, or with microsparitic domains. Our study concurrently support the ideas of their inorganic origin depending on evaporitic soil regime. This formations have its own historic dynamics on which depends also the preservation of calcaric nature of soils.