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Proactive disclosure Print version   | |  Geochemical Modeling Mapping Soil Mineralogy
Minerals are both sources and sinks for trace elements. Wide variations in physical and chemical properties of minerals lead to differences in soil weathering rates and reactivity. Despite the key role of minerals in soil development, they are difficult, expensive, and time-consuming to analyze, often requiring use of different techniques for different size fractions. X-ray diffraction (XRD), for example, is used for clay-sized (<0.002 mm) minerals, whereas optical methods are used for grains sand-sized and larger. Quantitative analyses by those two approaches cannot be directly compared, and they provide minimal additional information of environmental value, including grain shape and weathering features. The basis for mineralogical analyses of silt-sized (0.063 - 0.002mm) grains is not well understood. The application of mineralogical analyses based on Energy Dispersive Spectrophotometry (EDS) - scanning electron microscope (SEM) image analyses (Knight et al., 2002) of soils is being investigated. EDS-SEM image analyses is well suited for silt- and fine sand-sized grains, and can quantify and link compositional and morphological (grain size, shape, and weathering coating) attributes. Outputs A new protocol for mineralogical analyses of silt-sized particulate and demonstration of its potential for environmental studies. Participants
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