Canadian cordillera sedimentary basin studies

加拿大山脉沉积盆地研究

• 批准号: 184290-2008
• 负责人: Mustard, Peter
• 金额: $ 1.46万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=392321
• 关键词: Canadian; cordillera; sedimentary; basin; studies

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.

大约 190 至 4000 万年前，现在的加拿大西部科迪勒拉山脉内形成了几个沉积盆地。这是该地区演化的关键时期，大片地壳（地体）增加到北美西缘，导致该边缘变形，形成主要山脉带和多种类型的大规模断层。 这些盆地沉积的沉积物保留了盆地边缘变形类型和变化历史的记录。 可以通过查看构成砂岩的特定矿物类型、砾岩中碎屑的岩石类型以及泥岩的化学成分来检查该记录。 通过仔细重建这些盆地的沉积历史和源区的变化，可以推断盆地形成过程中主要变形事件的时间和模式，并在某些情况下推断盆地接收沉积物时它们在北美边缘的位置（各个盆地和下伏地体的位置目前引起激烈争论）。其中许多盆地也是已知或潜在的重要经济资源来源，包括石油、天然气、煤炭和煤层气。对这些盆地的详细地质研究对于确定发现这些资源的潜力以及将搜索范围缩小到最有前景的区域都很重要。进行此类研究的一个关键要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，进而了解当时存在的盆地类型。 测量和系统记录任何原始当前指标（水或空气）的方向也至关重要，这些指标为沉积物源区的位置提供了直接证据，这些沉积物现在是这些盆地中的沉积岩。