Weathering and Soil Formation
In the coastal regions of Antarctica, soil formation occurs to a greater extent than previously thought (Blume et al. 1997; Beyer et al. 1999). Soil formation can be found in accordance with humid climate conditions, as physical and chemical weathering wh
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8.1 Introduction In the coastal regions of Antarctica, soil formation occurs to a greater extent than previously thought (Blume et al. 1997; Beyer et al. 1999). Soil formation can be found in accordance with humid climate conditions, as physical and chemical weathering which results in acidification,brownification,clay formation, organic matter accumulation, as well as partial podzolisation and redoximorphism. Such phenomena have been described during studies of soils at Wilkes Land near Casey Station (Blume and Bölter 1993; Beyer et al. 1998; Blume et al., Chap. 7), and at King George Island near Arctowski Station (Kuhn 1997; Blume et al., Chap. 7). In contrast, soils of the cold deserts of the Ross Sea section are characterised only by physical weathering in combination with an accumulation of carbonates and salts, but there is nearly no humus accumulation (Campbell and Claridge l987; Bockheim and Ugolini 1990; Beyer et al. 1999). In recent reviews some more chemical and mineralogical data of representative soils have been given (Blume et al., Chap 7). This contribution discusses the main reasons for soil formation in Antarctic areas.
8.2 Sites and Methodology 8.2.1 Soil Analyses Three soils (Hapli- and Stagni-turbic Cryosols, Skeleti-gelic Podzol) near Casey,Wilkes Land in Continental East Antarctica, and five soils (calcari-regic and Skeleti-stagnic Cryosols, Molli-gelic Cambisol, Skeleti-gelic Podzol and Humi-gelic Umbrisol) near Arctowski, King George Island in maritime Antarctica were studied. The site and special soil properties are described by Blume et al., Chap. 7. Methods are described in detail by Blume et al., Chap. 7. Oxalate extractable Feo, Alo, Mno and Sio, pyrophosphate-extractable Alp, Fep, partly exchangeable Alp, dithionite-citrate extractable Ald and Fed, hot-acid (HCl) extractable Fev and Mnv fractions. Optical density of oxalate extract Ecological Studies, Vol. 154 L. Beyer and M. Bölter (eds.) Geoecology of Antarctic Ice-Free Coastal Landscapes © Springer-Verlag Berlin Heidelberg 2002
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(ODOE) as well as the optical density of the pyrophosphate extract (ODPE) are required to unravel soil weathering and formation. Fev–Fed (Fev-d) reflects the iron of the clay minerals. Fed–Feo (Fed-o) stands for well-crystallised iron oxides like goethite and lepidocrocite. Feo–Fep (Feo-p) is poorly-crystallised iron oxides like ferrihydrite, but also iron carbonates. Fep reflects organically bound (and exchangeable) iron as well as iron phosphates. The same pattern is valid for Al and Mn compounds, but not as good as for Fe. Occasionally, with high content of iron phosphates, data for Fep may be higher than for Feo. The reason for this is that Fe- (and Al-) phosphates are not soluble at pH 3.25. Weathering and clay formation is normally associated with an enrichment of Fe-, Al- and Mn-oxides. However, their contents are normally highly correlated with the clay content. Therefore, the impact of podzolisation or gleying on soils is better reflected by using clay-related (oxides/clay
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