Regional patterns of reflectance in lignites of the Ravenscrag Formation, Saskatchewan, Canada

Abstract

Random reflectances in oil ( R om) were measured on lignite samples from 60 boreholes in southern Saskatchewan covering an area from the Cypress Hills to Estevan. Measurements were made on three macerals of the huminite group, namely eu-ulminites A and B and corpohuminite. The study showed these results: 1. (1) Reflectance values on eu-ulminite A vary from 0.18 to 0.42; the range in eu-ulminite B is from 0.28 to 0.46 and in corpohuminite from 0.33 to 0.48. 2. (2) Along a west to east section line a subtle but consistent eastward increase in reflectance was observed from Wood Mountain to Estevan. 3. (3) Of the three macerals studied, eu-ulminite A seemed to be most sensitive to change and to show the most uniform behaviour along the west to east section line. 4. (4) Rank variations appear to be related to present-day heat flow patterns determined by geothermic studies. Areas of low geothermal gradients coincide with areas of lower reflectances in the Ravenscrag coals while higher reflecting coals are associated with areas of higher geothermal gradients.