Organic petrology and geochemistry of intermontane coals from British Columbia: 3. The Blakeburn opencast mine near Tulameen, British Columbia, Canada

Abstract

Rank, maceral composition and elemental concentrations of coals, volcanoclastics and sedimentary partings from coal-bearing strata in the Blakeburn opencast mine, British Columbia, are determined using reflected light microscopy, INAA and inductively coupled plasma emission spectrometry (boron only). Petrologically, the coal is similar to that from the Hat Creek coal deposits Nos. 1 and 2 of British Columbia, with vitrinite the dominant maceral group and inertinite macerals contributing only a small percentage. Three depositional cycles are observed; each representing a particular sedimentological and petrological environment of deposition. The coal in Cycles I and II was deposited in a freshwater environment with an almost uniform rate of subsidence; the coal in Cycle III also formed in a freshwater environment but was subject to erratic subsidence rates. Distribution of certain elements is similar to that of the Hat Creek coals (e.g., Al, Br, Cr, Ca, Mo, Se, Ti, W), indicating a certain degree of regional lateral persistence of elemental distribution. Vertical variations of elemental concentrations are primarily related to the lithology. Organically-bound elements are concentrated mainly in coal, and inorganically bound elements are found in the volcanoclastic and sedimentary partings.