This paper presents a new method for portraying and quantifying the macropetrography of lignites, and which can be used to identify, characterize, and map coal seam lithofacies. The method was developed during our current studies of lignite seams in the Ravenscrag Formation (Paleocene) of southern Saskatchewan, Canada. A newly exposed face of one seam and fresh drillcore of 18 other seams, showed only indistinct layering, but when the lignites were sectioned by dry sawing, much greater proportions of xylite and fusain were revealed and the layering became obvious. The clarity of detail revealed in the sectioned faces enabled the xylite, fusain, and coal/elastic contacts to be readily traced, providing true-scale graphic representations of the macropetrography. In general, the representations of individual samples or lithofacies are referred to as lithographs, while those of seam profiles are termed lith-logs. The procedures for producing lithographs and lith-logs, and for quantifying the macropetrography that they portray, are described.

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