Folds, Faults, And Hydrocarbons In The Southern Canadian Cordillera
INSTRUCTOR: Peter Jones, PhD
DISCIPLINE: Field Course
COURSE LENGTH (DAYS): 4 Days
WHO SHOULD ATTEND: Geologists, geophysicists and geoscience managers working compressional tectonic settings.
COURSE DESCRIPTION: This intense four day short course and field trip begins with two days of classroom discussion aimed at demonstrating the value of thinking in three-dimensions and understanding the structural principles and practices applicable to deformed terrains on-and off-shore. Opening with the short AAPG video “Birth of the Rockies,” the course leads the participant through fault and fold terminology, geometry and mechanics, evolving interpretational styles and their application to interpretations of seismic profiles.
PowerPoint illustrated lectures are punctuated with workshop examples, mainly involving construction and evaluation of geological cross-sections. A comprehensive sourcebook is provided for participants’ reference, as well as a separate volume of workshop exercises.
The important theme for oil and gas exploration is that nothing is unique. If a new and different type of structure is discovered, it means that the others have not yet been found or recognized.
THE TWO-DAY FIELD TRIP
Starting from Calgary, the field trip traverses the foothills and Rockies southwestward to the Rocky Mountain Trench, which marks the western limit of successful oil and coal exploration and eastern limit of exposed metamorphic and intruded Paleozoic and Proterozoic rocks.
Our route will take us westward from Calgary through the foothills into the eastern Rockies, crossing three major thrust-faulted gas fields whose surface expressions are exposed in Tertiary to Cambrian sedimentary rocks. Turning southward, the route follows and jogs between parallel mountain valleys across passes with a maximum elevation of 7,000 feet (2100metres), on paved highways and good quality gravel roads. Turning to the west, our route crosses the continental divide and the Lewis thrust sheet, largest thrust sheet in North America, whose regional aspect as well as its complex internal structure are both beautifully exposed. Continuing westward, the route crosses the huge Flathead normal fault, entry into the Jurassic Fernie coal basin. The trip turns around at the Rocky Mountain Trench, the 1500-km long fault-bounded valley that extends from Alaska to Montana, and marks the western limit of the Rocky Mountains.
The return eastward takes in structures by-passed on the outward leg, traverses abandoned underground mining areas and huge,carefully concealed active open-pit mines with a locally famous historical landslide/mining disaster as well as regional-scale landslides. At the east edge of the foothills, the route turns northward following the Triangle zone northward and back to Calgary via the Turner Valley oilfield, first major oil and gas field in Canada, still producing from horizontal wells.
- Introduction: thick- and thin-skinned structures, plate tectonics
- Thrust faults: traditional, listric, folded and blind
- Fault kinematics, duplex reservoir structures
- Wedge tectonics and detachments
- Normal faults: traditional, listric, folded, and blind
- Gravity tectonics
- Basement-involved structures
- Strike-slip faults and associated structures
- Relationships between fold and faults
- Diapiric structures in salt, clay, and coal
- Real and spurious unconformities
- Inversion tectonics
- Unrecognized hydrocarbon traps and what to look for
- Use and construction of geologic maps and cross-sections.
- Balanced cross-sections: construction, uses, and caveats
- Analogue models of geologic structures.
- Basic seismic interpretation