Some geochemical aspects of sedimentary rocks in proximity of coals, sydney coalfield (upper carboniferous), cape breton island, nova scotia, canada

Channel samples of roof and seat rocks (lutites, siltstone)) of 10 successional coals, in addition to red mudstone and calcareous siltstones, have been collected from the Sydney Coalfield, Nova Scotia. The channel samples are confined to within 150 cm above the top of coals, and to within 20 cm below the bottom of coals. Whole-rock and trace-elemental analyses are reported: wt. % of oxides of Si, Al, total Fe, Ca, Mg, Na, K, T1, Mn; and ppm's for Cu, Ni, Pb, Zn, Cr, Co, Ga, V, As, U, and Th, respectively. Th/U ratios, organic carbon and carbonate carbon of selected roof rock samples are also reported.The comparatively small stratugraphic mean variations of Na₂/K₂O and Na₂O/Al₂O₃ are open to interpretation but may indicate either a common sedimentary source, or a similar diagenetic history during basin development. Assumed is that the oxide ratios originated from detrital feldspars and clays. The probability model for uranium is Pearson's Type VII curve. The relationship between uranium (thorium) and (assumed) organic calcite in selected calcareous siltstones is examined. Stratigraphic variation of the geochemistry is assumed to be cycle-controlled, excepting probably As, V, and Cu,which under the stated conditions are amenable to mathematical modeling (of sedimentary cycles).