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UGR scientists discover alterations in Sierra Nevada´s quartz

The analysis of quartz grains of light fine sand of Sierra Nevada directed by Professor Delgado Calvo-Flores has highlighted “the existence of important physical/chemical alterations like fractures, corrosion gulfs, etch pit edges and intergranular surface dissolution, corroborating these processes with «electron micro-probe analisys» (EMPA), since analyses show that grains contain a higher proportion of cations different to Si in edge areas than in centre areas». University of Granada scientists question that Sierra Nevada´s superficial activity (the highest southern mountain range of the European continent) is essentially physical.

Quartz is one of the most abundant elements in the soil of Sierra Nevada and has traditionally been considered stable against chemical alteration in temperate climates.

According to Professor Delgado, «quartz has been considered to be almost chemically unaltered in Mediterranean climate soils and for this reason it has been used in this environment as an invariant mineral in evaluation studies of quantitative materials». According to the study, quartz alteration in soils is due both to the climate and the weathering time.

The research work has highlighted morphological and analytical features traditionally attributed to scarcely evolved soils. In this sense, the limited evolution of Sierra Nevada´s soils has been traditionally attributed to two factors: relief, as they are located in hillsides with slopes, which conditions erosive processes that make profile development difficult and the mountainous Mediterranean climate, with low temperatures and moderate rainfall.

UGR scientists in charge of the reserach work suggest studying quartz mineral in the sand area of Entisoles in the interior area of Sierra Nevada. According to the person in charge, the research «will bring awareness about quartz genesis in soil, edaphogenetic environment aggressiveness, its possible use as invariant mineral in material balances, etc».

Two profiles of Entisoles were chosen to carry out the fieldwork sampled in the northern slope Sierra Nevada; the Natural Reserve of Sierra Nevada is located in this mountain range, whose soil knowledge is pioneer among Spanish national reserves thanks to the scientific work developed by the University of Granada.

In this sense, the research lines developed by Professor Delgado Calvo-Flores, in connection with the study of Sierra Nevada, refer to soil cartography, typologies, soil-use evaluation, soil degradation (erosion, vegetation replacement), soil genesis, mineralogy, geochemistry of superficial alterations and soil-landscape relationships.

Rafael Delgado Calvo-Flores.
Dpt. of Edaphology and Agricultural Chemistry.
Faculty of Pharmacy. University of Granada.
Phone number: 958 243835.