Pseudovitrinite: Possible Implications for Gas Saturation in Coals and Surrounding Rocks
Coal Petrography is for many a black science using terms that are for some not only incomprehensible but also in flux. For utilization purposes, the organic component of coal is generally broken down into reactive and non-reactive macerals, often with little further differentiation of the macerals. The main incentive to differentiate further is the recognition that the degree of reactivity in vitrinite macerals and the degree of non-reactivity in inert macerals, both vary.
Effects of carbon dioxide storage in coal on the physical and chemical properties of coal
iii In comparing the effects of subcritical and supercritical treatment on CO2 sorption behaviour over time, the study determined that the long term effects of CO2 storage in coal were found to be dependent on the maceral composition of the coal, with the vitrinite-rich coal showing a more pronounced structural and properties change after CO2 storage. This change did, however, differ under subcritical and supercritical conditions. Inertinite-rich coal was found to be less prone to changes under CO2 storage. A major implication of this finding is the inclusion of maceral composition as major criteria for determining CO2 storage in coal capability. The results in this study contribute significantly to the understanding of coal-CO2 interactions and the implications for coal structure and properties changes; the results could be used by decision-makers on the effects of storing CO2 in coal.
Rates, Controls, and Sand-Body Geometries of Transgressive-Regressive Cycles: Cretaceous Moosebar and Gates Formations, British Columbia
The Moosebar and Gates Formations (Lower Cretaceous) in northeastern British Columbia consist of seven transgressive-regressive sequence. Nonmarine sediments are thickest in the south and pinch out northward. The sequences are laterally persistent, extending east from the foothills for 240 km (150 mi). The orientation of maximum transgressive and regressive limits in five cycles occurs within an east-west-trending zone 30-40 km (19-25 mi) wide. A recurring, northward-bulging sediment depocenter near the Alberta-British Columbia border was fed by a series of stacked, northerly flowing rivers. The rivers were a major source of sediment for gravel beaches to the north and east. Isopach maps of marine sandstone and conglomerate show a series of west-northwest-east-southeast-o iented sand bodies 60-70 km (37-43 mi) wide, parallel with the shorelines. Each coastline prograded northward as a shoreline-attached strand plain and a series of arcuate or cuspate deltas. Gates Formation marine-nonmarine cyclicity is a series of fourth-order cycles superimposed on a major third-order cycle. The cyclicity and lateral extent of the sequences can be explained as a result of tectonic thrusting and loading superimposed on the trend of the Peace River arch. The influence of eustatic sea level variations and sedimentologic switching of point sources had minimal effect. Coastal retreat ranged from 437 to 875 m/1,000 years (1,433 to 2,780 ft/1,000 years). Coastal progradation ranged from 218 to 437 m/1,000 years (175 to 1,433 ft/1,000 years). The duration of several transgressive-regressive cycles was 103,000-275,000 years.