Regional pattern of thermal maturation as determined from coal-rank studies, Rocky Mountain foothills and Front Ranges north of Grande Cache, Alberta; implications for petroleum exploration
Regional pattern of thermal maturation as determined from coal-rank studies, Rocky Mountain foothills and Front Ranges north of Grande Cache, Alberta; implications for petroleum exploration
Bulletin of Canadian Petroleum Geology (September 1984) 32 (3): 249-271
- Alberta
- biochemistry
- burial
- Canada
- Canadian Rocky Mountains
- Carboniferous
- coal
- coal exploration
- color
- Conodonta
- Cretaceous
- Dinantian
- economic geology
- energy sources
- Front Range
- hydrocarbons
- Laramide Orogeny
- maturity
- Mesozoic
- methods
- microfossils
- natural gas
- North America
- organic compounds
- organic materials
- organic residues
- Paleozoic
- petroleum
- petroleum exploration
- rank
- regional patterns
- reservoir rocks
- Rocky Mountains
- Rundle Group
- sedimentary rocks
- structural traps
- thermal alteration
- traps
- Triassic
- Western Canada
- Grande Cache
- Alberta Syncline
In contrast to results from the southern Canadian Rocky Mountains and Foothills, coal rank studies in the region north of Grande Cache, Alberta show that the degree of thermal maturation at the Lower Cretaceous level decreases progressively from the core of the Alberta Syncline to the western edge of the Foothills. Hand-picked coaly particles and the colour alteration of conodonts from the Lower Carboniferous Rundle Group indicate an even lower level of maturation in the Front Ranges. Time-depth (burial) curves suggest that the westward decrease in level of maturation is due to a westward decrease in the duration and depth of burial beneath Upper Cretaceous - Tertiary clastic deposits, largely as a consequence of the timing of Laramide deformation across the area. In the west, early Laramide uplift prevented deep burial and terminated the maturation whereas, in the east, Lower Cretaceous strata were deeply buried and maturation continued. Calculations based on time-depth (burial) curves suggest that the level of thermal maturation of Triassic and Carboniferous carbonates decreases from dry gas to overmature under the outer Foothills to oil preservation - wet gas under the western part of the inner Foothills. With these potential reservoir rocks forming structural traps at relatively shallow depth, the western part of the inner Foothills north of Grande Cache, Alberta could be a prospective area for petroleum exploration.