Geochemistry And Sedimentology Of Two Cretaceous Coal Deposits In Canada

• Main Author: Van, Der Flier
• Format: Text
• Language: unknown
• Published: Scholarship@Western 1985
• Subjects: Geology; British Columbia; Canada; Moose River
• Online Access: https://ir.lib.uwo.ca/digitizedtheses/1468; https://ir.lib.uwo.ca/context/digitizedtheses/article/2467/viewcontent/NL20727.PDF

The sedimentology and mineralogy of coals and sediments in a coal-bearing sequence have an important influence on the geochemistry and trace element siting and distribution. The objective of this study is to make an analysis of each of these aspects and to examine how they are interrelated.;The two Lower Cretaceous coal-bearing sequences studied are in the Moose River Basin in northern Ontario and the Monkman region in eastern British Columbia.;The sequences were deposited in fluvial and upper delta plain/fluvial environments respectively. The mineralogy of the Moose River Basin sediments consists of quartz, kaolinite, minor illite/muscovite, pyrite, calcite, siderite and rare gibbsite. The lignites contain dominantly quartz and kaolinite. The Monkman sediments in addition to the assemblage mentioned above contain ankerite, higher proportions of illite and mixed layer clays and no gibbsite. The Monkman coals have a higher proportion of mineral-rich bands and contain a greater variety of minerals than the Moose River Basin lignites.;Major and trace elements were analysed by XRF, AA, NAA, DNC, DCP, EMS, and ESCA. Pearson correlation coefficients coupled with SEM-EDX were used to examine the modes of occurrence of trace elements. Trace element concentrations and associations were found to be extremely variable.;The most common mode of trace element occurrence (e.g. for Cu, Rb, Cr, Au, U, Ti, V, Ni, Zn and in part P, Co, As, Sr, Y, Zr, Nb, Mo, Pb and Th) is in association with the clay minerals. Cl, Zn, Mo and Pb are associated entirely with the organics in the Moose River Basin lignites. This is also true for Ga in the Monkman coals. Zirconium, Ti, Th and in some cases Cr and U occur associated with detrital heavy minerals. Cobalt, As and W in some sample sets are associated with the sulphides. Phosphorous and Sr are predominantly associated with carbonates.;Several factors which influence the trace element characteristics of the coal and sediments are proposed. These include mineralogy, depositional environment, ...