Canadian cordillera sedimentary basin studies

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Several sedimentary basins formed within what is now the western Canada Cordillera between about 190 and 40 million years ago. This was a critical time in the evolution of this area with large sections of the earth's crust (terranes) added to the western margin of North America and resultant deformation of this margin causing major mountain belts and several types of large-scale faulting. The sediments deposited in these basins preserve a record of the types of deformation and history of changes along the margins of the basins. This record can be examined by looking at the specific types of minerals which make up the sandstone, the rock types of clasts in conglomerates, and the chemistry of the mudstone. By carefully reconstructing this depositional history and the changes in source areas in these basins it is possible to infer the timing and patterns of the major deformation events during the basin formation and in some instances to infer their position along the North American margins at the time when the basins were receiving sediment (the position of the various basins and underlying terranes is currently hotly debated). Many of these basins are also known or potential sources for signifcant economic resourcs, including oil, gas, coal and coalbed methane. Detailed geologic studies of these basins are important in both decerning the potential to find these resources and in narrowing the search to the most prospective areas. A key element in conducting these types of studies is to very carefully document the internal structure (faults and folds for example) and sedimentatry features of the basin. This includes mapping the different geologic units within the basin at a much more detailed scale than presently available, and demonstrating the types, thicknesses and variations of sedimentary rocks and their specific characteristics to understand the type of depositional environment that controlled their formation and in turn the type of basin that was present. It is also crucial to measure and systematically document the directions of any original current indicators (water or air) that provide the direct evidence for the location of the source areas for the sediments which are now sedimentary rocks in these basins.