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TitreMineralogical and elemental composition of tonsteins from the East Kootenay Coalfields, southeastern British Columbia
AuteurGoodarzi, F; Grieve, D A; Labonte, M
SourceGlobal Change: the Geothermal Aspects of Coal; par Fyfe, W S (éd.); Goodarzi, F (éd.); Energy Sources vol. 12, no. 3, 1990 p. 265-295,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 48689
ÉditeurInforma UK Limited
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC82J; 82G/NW; 82G/10; 82G/15
Lat/Long OENS-116.0000 -114.0000 51.0000 49.5000
Sujetshouille grasse; distribution des éléments; analyses minéralogiques; charbon; altération; analyses par diffraction des rayons x; analyses par activation neutronique; analyses des éléments en trace; analyses; analyses des éléments majeurs; analyses géochimiques; méthodes statistiques; altération; géochimie des terres rares; Champ de charbon de Crowsnest ; Champ de charbon d'Elk Valley ; Champ de charbon de Flathead ; Groupe de Kootenay ; Formation de Kootenay ; Formation de Mist Mountain ; combustibles fossiles; minéralogie; géochimie; géomathématique; Crétacé; Jurassique
Illustrationssketch maps; charts; tables
Résumé(disponible en anglais seulement)
A suite of 24 tonsteins from the East Kootenay Coalfields is studied for mineralogical and elemental composition, origin, and the degree of physical and chemical alteration, using x-ray diffraction (XRD), x-ray fluorescence (XRF), instrumental neutron activation analysis (INAA), and inductively coupled plasma (ICP). Concentration of elements greater than the Clarke value is often limited to the litho-philes, i.e., Al. B, Ba, Cr. Co, Cs, Cu, Fe, K, Rb, Mg, Si, Sr, Th, and U, and some chalcophiles, i.e.. As, Sb, Se, and Mo. However, some lithophiles, such as Br, Ca, and CI, are depleted in these samples. The elements Al, Ca, Co, Hf, K, Mg, Na, Th, Se, U, andREEs (rare earth elements) are sensitive indicators of origin and degree of alteration of these tonsteins. Statistical analyses allow indirect observation of the stages of leaching that have affected the tonsteins. The Kootenay tonsteins are divided into two groups based on their mineralogy and elemental composition: (1) tonsteins rich in Ba and REE which contain significant amounts of gorceixite and kaolinite; and (2) tonsteins with kaolinite as the only major mineral and quartz and gorceixite as minor constituents or absent. The grouping of tonsteins roughly correlates with the stratigraphic position of samples. Samples from the basal part of the section contain high concentrations of Coand Hf, whereas those from the upper portion of the coal-bearing strata have relatively high concentrations of Th and REEs. The sediments in proximity to tonsteins can be correlated by using mineralogical and elemental concentrations. For example, tonsteins containing the mineral, gorceixite, which is rich in REEs, are located in geographically limited areas, indicating similar origins, and therefore sediments associated with the tonsteins can be correlated. The rare earth elements diagram (spidergram) gives a more detailed view of behavior of the tomeins in terms of their compositions. The REEs and Th are useful elements for considering the depositional environments in general. Weathering and leaching of tonsteins is evident by the depletion of the authigenicuranium.