Seminal infrared-based chemometric analysis of oxygen-bearing structural groups in vitrain samples from ten successive coal seams (Sydney Coalfield, Canada)

Abstract

Reported are seminal results of a systematic application of infrared spectrometry to a succession of coal seams in a Carboniferous basin from Sydney Coalfield, Nova Scotia, Canada. Fifty-four lithotypic vitrain samples from ten successive coal seams were analyzed by solid-state (potassium-bromide pellet method) Fourier transform infrared spectroscopy and evaluated using principal-component analysis to explore chemical fingerprints of vitrain structural-group contents and distributions. At this level of sampling, the 3D principal-component analysis and ANOVA tests identified chemical structural-group changes related to relatively low contents of aliphatic and oxygen-bearing compounds. These probably confirm, for data represented by “younger” seams, the moderate thermal histories (0.75–0.90 Ro %) from which minimal diagenetic alterations are inferred in the preservation of fossils in the roof rocks of the coal seams. It is concluded that, throughout the lithostratigraphic column, the continual vertical changes in vitrain structural-group composition are related to some changes in the species diversity of the associated macroflora that filled niches in the peat-producing lower flood plains.