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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 5. (May)

First Page: 636

Last Page: 637

Title: Paragenetic Relation of Thermal Maturation (Coalification) and Tectonic Framework of Some Canadian Rocky Mountain Coal: ABSTRACT

Author(s): Francis T. C. Ting

Article Type: Meeting abstract

Abstract:

The attitude of the reflectance indicatrix of coal is a function of thermal history (coalification) and stresses (tectonics) at the time of maximum coalification. In normally coalified, horizontal-bedded coal seams, the maximum reflectance lies in a horizontal

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plane parallel with bedding plane and the minimum reflectance axis is perpendicular to the bedding plane. If maximum reflectance is achieved prior to folding, the minimum reflectance is always perpendicular to the bedding regardless of the subsequent folding and the attitudes of the coal beds. Thus, the attitude of the minimum reflectance is a good parameter for evaluating whether maximum thermal maturation is achieved prior or after folding or other structural changes. Twenty-five samples were collected from coal-bearing strata from Monkman's Pass north to Sparwood, British Columbia, in the Canadian Rockies. Most of the coal beds sampled were highly disturbed by folding and faulting with dips ranging from a few degrees to overturned. Analysis results indicate distinctive groupings of the samples with the minimum reflectance deviating a few degrees to more than 30° from the normal of the bedding. This suggests a varied thermal history for the coal fields studied. The technique can be applied not only to the investigation of coal-bearing strata but also to the study of source rocks of petroleum as to whether thermal maturation occurs before or after a trap has been developed.

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