Weathering of ultramafic rocks and element mobility at Mt. Prinzera, Northern Apennines, Italy

Abstract

The weathering of the Mt. Prinzera serpentinites (Parma province, Northern Apennines, Italy) produced dominant smectite and minor Fe-hydroxides. The mobility of the elements during weathering has been estimated using the ratio Ki = MiS/MiR, where Mi indicates the mass of a generic component i before (R) and after (S) the weathering, and using TiO2 as a practically immobile component. For prevalently to tendentially mobile elements, the degree of mobility, which in our case increases as Ki decreases, is in the order Mn ≈ Cr = Fe < V ≈ Zn ≈ Co < Ni < Si < Mg < Ca. The elements Ti, Ga, Al and Zr are prevalently immobile. The mass chemically removed by the circulating waters during weathering may reach very high values (on average 52% of the original mass of serpentinite) and the main contribution to the mass loss is due to Si and Mg. The composition of the perennial and ephemeral springs in the area is in agreement with the degree of the element mobility at least for Cr, Mg and Ca.

Evaluating the degree of weathering in landslide-prone soils in the humid tropics: The case of Limbe, SW Cameroon

“…The mobility and redistribution of elements within the secondary environment have been widely used to estimate the degree of weathering and the behaviour of elements during weathering (Beyala et al, 2009). Venturelli et al (1997) suggested that reliable information on element mobility during weathering may be obtained by quantitative mass balance approaches. In most mass balance models, one or more elements are isolated and assumed to be immobile (Anderson et al, 2002;Brimhall and Dietrich, 1987;Brimhall et al, 1985;Nesbitt and Young, 1982).…”

Chemical composition of surface- and groundwater in fast-weathering silicate rocks in the Seiland Igneous Province, North Norway

“…Investigations on surface waters in ultramafic rock and/ or gabbro catchments have been carried out by, e.g., Barnes & O'Neil (1969), Barnes et al (1978), Clark & Fontes (1990), Gascogne & Kamieni (1993), Drever (1997), Venturelli et al (1997), Zedef et al (2000), Zakharova et al (2007), Zhou (2010), Chavagnac et al (2013) and Bucher et al (2015). Typical waters from ultramafic rock terrains are Mg-HCO 3 type waters with elevated pH values.…”

Geochemical inheritance of soils that develop from volcanic rocks (Navarra, Western Pyrenees)

“…After considering possible immobile elements in the references consulted (Kurtz et al, 2000;Tapia et al, 1998;Nesbitt and Markovics, 1997;Venturelli et al, 1997), and observing the behaviour of the immobile elements (Fig. 3), those elements that always showed a near zero balance, i.e.…”

“…not significant) balance. We obtained the element mass balance by applying the formula below (1) (Kurtz et al, 2000;Tapia et al, 1998;Venturelli et al, 1997;Bain et al, 1993;Nesbbit, 1979;Nesbitt and Markovics, 1997). The term Xn is positive when there is a gain of an element in the soil, and negative if there has been a loss of an element with respect to its content in the parent material, and compared to the content of an immobile element.…”

“…We also attempt to quantify the contribution of the rock to the geochemical character of the soils that develop above them. Several studies have already shown that parent material has a strong influence on soil chemistry (Palumbo et al, 2000;Vaselli et al, 1997;Venturelli et al, 1997;Dekayir and El-Maâtaoui, 2001;Driese et al, 2003). However, we have centred our interest on soils that have developed from a very distinctive rock lithology, namely basic igneous rocks, which we separated into two groups according to their magmatic affinity:…”