D&apos

Freppaz, Michele

Zanini, Ermanno

English

D'Amico, Michele

Institutional Research Information System University of Turin

Geophysical Research AbstractsVol. 15, EGU2013-12706, 2013EGU General Assembly 2013© Author(s) 2013. CC Attribution 3.0 License.“Fast pedogenesis” on proglacial areas: examples from the north-westernItalian AlpsMichele D’Amico, Michele Freppaz, and Ermanno ZaniniTorino, DISAFA, Grugliasco (To), Italy (ecomike77@gmail.com)Climate changes have huge impacts on alpine ecosystems. One of the most visible effects is glacial retreat sincethe end of the Little Ice Age (LIA: 190-190 years ago), which caused the exposure of previously glaciatedsurfaces. These surfaces are open-air laboratories, verifying theories regarding ecosystem and soil development.In order to increase our knowledge on the effect of time and vegetation primary succession on soil development inproglacial areas, we sampled soils and surveyed plant communities on stable points on the proglacial areas of theLys and Verra Grande glaciers, in the Italian north-western Alps (Valle d’Aosta). Sampling sites were located ondated sites (6-260 years), on the basis of literature or historical photographs).Glacial till is attacked by weathering processes immediately after deposition and stabilization, such as lossof soluble compounds, acidification, primary mineral weathering. The speed of these processes are largelyincreased after the establishment of a continuous vegetation cover, thanks to surface stabilization, organic matteraccumulation caused by litter input and root decomposition below the soil surface.On sialic glacial tills (Lys forefield), below timberline and under a larch – Rhododendron forest, a fast and steadydecrease in pH values, increase in organic matter content and horizon differentiation were observed. In particular,genetic eluvial horizons formed in just 60 years, while diagnostic albic horizons were developed after ca. 90 years,evidencing an early start of the podzolization processes. Cheluviation of Fe and, secondarily, Al were analyticallyverified. However, illuviation of Fe, Al and organic matter in incipient B horizons was not sufficient to obtaindiagnostic spodic horizons on LIA materials.Under grazed grassland below timberline and alpine prairie above timberline, acidification and weathering wereslightly slower, and no redistribution with depth of Fe and Al oxi-hydroxides was observed. A cambic Bw horizondeveloped on the oldest LIA moraines.On ultramafic materials (Verra Grande glacier forefield), vegetation succession was inhibited by toxic concentra-tion of available Ni and Mg and scarcity of nutrients; this inhibited the organic matter input on the soil surface,slowing down acidification, base leaching and mineral weathering. However, soon after the establishment of thetypical subalpine larch-Rhododendron forest on 190-260 years old moraines, a visible E horizon could form,overlying an organic matter and metal-enriched incipient Bs horizon.

“Fast pedogenesis” on proglacial areas: examples from the north-western Italian Alps

https://iris.unito.it/bitstream/2318/1550813/1/EGU2013-12706.pdf

“Fast pedogenesis” on proglacial areas: examples from the north-western Italian Alps

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&#8220;Fast pedogenesis&#8221; on proglacial areas: examples from the north-western Italian Alps

Abstract

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Institutional Research Information System University of Turin

“Fast pedogenesis” on proglacial areas: examples from the north-western Italian Alps