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Normative calculation of minerals in North German loess soils using the modified CIPW norm
Author(s) -
Tarrah Jamal,
Meiwes Karl Josef,
Meesenburg Henning
Publication year - 2000
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/1522-2624(200006)163:3<307::aid-jpln307>3.0.co;2-i
Subject(s) - loess , soil water , mineralogy , mica , illite , dolomite , muscovite , chemical composition , calcite , albite , composition (language) , chemistry , geology , quartz , clay minerals , soil science , geomorphology , paleontology , linguistics , philosophy , organic chemistry
The quantitative mineralogical composition which determines considerably the acid buffering capacity of soils can either be analyzed directly (modal) using mineralogical methods or can be calculated (normative) from the chemical total analysis of the soil considering previous knowledge of its qualitative mineralogical composition. In this study the normative mineralogical composition of loess‐derived soils in Northern Germany is compared with their modal mineralogical composition determined by X‐ray diffractometry and infrared spectroscopy. The CIPW norm (acronym for Cross, Iddings, Pirsson and Washington; Cross et al., 1902) has been used to calculate the mineralogical composition. For the application to soils the CIPW norm had to be modified with respect to pedogenic minerals. The differences between the normative (n) mineral contents and the respective modal (m) data [(n‐m) × m −1 × 100] are for quartz −10% ± 4% (mean ± standard deviation), for orthoclase −8% ± 24%, for albite 26% ± 17%, for illite/mica −9% ± 24%, for calcite 14% ± 2%, and for dolomite 11% ± 19%. The chemical composition of illite/mica has been defined horizon‐specific. The differences between normative and modal data are in the range of the error of mineralogical methods such as X‐ray and optical techniques. Therefore the modified CIPW norm proves to be useful to estimate quantitatively the mineralogical composition of loess‐derived soils.