Gneiss weathering soils

The highest arsenic contents from natural sources occur in plants grown on gneiss weathering soils in Central Europe, and the lowest on phyllite. The As content in plants depend on the individual plant spe-... 

Weathering soils of Buntstandstein Keuper weathering soils Gneiss weathering soils Pleistocene sands Least significant difference... 

Many of the above observations can be illustrated through discussion of an example of weathering taken from Goldich (1938) (see also Krauskopf 1967). The parent rock in this humid, temperate climate example is a quartz-feldspar-biotite gneiss. The mineralogic and oxide composition of this rock and its weathered product soil is given in Table 7.2. 

Results of a field study at Bear Brook Watershed, Maine, were compared with laboratory kinetic experiments using size-fractionated soils from the same location. It is a forested, glaciated region with thin podzolic soils and granitic gneiss bedrock. Fractional order dependence (m = 0.5) of weathering rales on H 1... 

Figure 19. Typical example of how uranium is released to the environment (redrawn and completed after Pfeifer et al. (1994)). By weathering and erosion U-rich ore quality material (pitchblende veins in granitic gneiss) is deposited on the slope beneath a cliff. The soil and plants devel-opping on it are enriched in uranium (up to 2500 ppm in the soils vs. 3 ppm in the reference soil outside the touched area, 50 m to the south-east, marked with r 100 mg/kg U in contaminated plants, - see Appendix A.8). The waters from this type of environment contain between 10 and 30 jxg/l U (cf. Fig. 18, Section 2.2 and Appendix A. 1).

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