Canadian cordillera sedimentary basin studies

大约在1.9亿至4000万年前，在现在的加拿大西部科迪勒拉山脉内形成了几个沉积盆地。这是一个关键的时间在这个地区的演变与大部分的地壳（地壳）添加到北美西部边缘和由此产生的变形，这一边缘造成主要的山区带和几种类型的大规模断层。 沉积在这些盆地中的沉积物保存了沿盆地边缘沿着的变形类型和变化历史的记录。 这些记录可以通过观察构成砂岩的特定类型的矿物、砾岩中碎屑的岩石类型以及泥岩的化学性质来检验。 通过仔细重建这些盆地的沉积历史和源区的变化，有可能推断出盆地形成期间主要变形事件的时间和模式，并在某些情况下推断出它们在盆地接受沉积物时沿着北美边缘的位置（目前对各种盆地和下伏沉积物的位置存在激烈争论）。这些盆地中的许多也是已知的或潜在的重要经济资源的来源，包括石油、天然气、煤和煤层气。对这些盆地进行详细的地质研究对于确定发现这些资源的潜力和将搜索范围缩小到最有前景的地区都很重要。进行这类研究的一个关键因素是非常仔细地记录盆地的内部结构（例如断层和褶皱）和沉积特征。 这包括以比目前更详细的比例绘制盆地内不同地质单元的地图，并展示沉积岩的类型、厚度和变化及其具体特征，以了解控制其形成的沉积环境类型，进而了解存在的盆地类型。 同样重要的是，必须测量和系统地记录任何原始水流指标（水或空气）的方向，这些指标为这些盆地中现在已成为沉积岩的沉积物的源区位置提供了直接证据。

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.