Integrated high-resolution stratigraphy: Deciphering fundamental controls on basin evolution

综合高分辨率地层学：破译盆地演化的基本控制因素

• 批准号: RGPIN-2018-05039
• 负责人: Plint, Alexander
• 金额: $ 2.19万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751174
• 关键词: Integrated; resolution; stratigraphy; Deciphering; fundamental

Sedimentary rocks provide the most important record of life on Earth, as well as recording the history of the atmosphere and oceans. The proposed programme of investigation is concerned with sedimentary rocks deposited during the Cretaceous Period, between about 108 and 83 million years ago in what is now NE British Columbia, Alberta and Saskatchewan. At that time, the Prairie region was occupied by a shallow sea that at times connected the Arctic Ocean with the Gulf of Mexico. To the west, the actively-rising Rocky Mountain chain was shedding sediment eastward into the Seaway, building deltas and coastal plains that supported a lush flora of both conifers, and, after about 104 million years ago, a rapidly diversifying assemblage of flowering plants. Environments ranging from the sandy sea shore to inland river valleys and floodplains were inhabited by many types of dinosaur, with hadrosaurs, ankylosaurs, and various theropods being particularly common. These animals are known mainly from the abundant footprints that they left in the sediments; - bones are rarely preserved. The Canadian Shield formed a low-lying land area in northern Saskatchewan and Manitoba that shed sediment westward into the seaway. We have discovered that at one time, a huge delta built out from the eastern shore to completely block the seaway. The mass of the rising Rocky Mountains depressed the crust for about 1000 km to the east, allowing a westward-thickening wedge of sediment to accumulate. Because deposition occurred in shallow water and on low-lying coastal plains, even small changes in sea-level caused lateral shifts in the shoreline position as the water alternately deepened and shallowed. Changes in the rate at which the basin subsided also caused major changes in the position of the ancient shoreline. Shoreline movements can be deduced by studying the vertical succession and lateral distribution of terrestrial, shoreline and offshore sediments. By mapping the distribution of these rock types using abundant exploration borehole data, as well as through outcrop study, it is possible to reconstruct how the geography of the basin evolved, and to assess the relative influence of sea-level (mostly controlled by changing climate), and subsidence or uplift (controlled by plate tectonics), on basin geography.The Cretaceous rocks of Western Canada provide not only a detailed record of evolving animals, plants, sea-level change and mountain-building, but also a wealth of natural resources, of vital interest to Provincial economies. Marine mudstones deposited in the centre of the seaway contain algal tissues that, with heat, pressure, and time, generated natural gas and petroleum that accumulated in the porous sandy shoreline sediments. Low-lying coastal plains accumulated thick peat deposits that later compacted to high-quality coal, that is of major economic significance in towns like Grande Cache and Tumbler Ridge.

沉积岩提供了地球上最重要的生命记录，也记录了大气和海洋的历史。 拟议的调查计划涉及白垩纪时期（约 108 至 8300 万年前）沉积在现在的不列颠哥伦比亚省、艾伯塔省和萨斯喀彻温省东北部的沉积岩。 当时，草原地区被浅海占据，有时将北冰洋与墨西哥湾连接起来。 在西边，不断上升的落基山脉将沉积物向东抛入海道，形成了三角洲和沿海平原，孕育着茂盛的针叶树植物群，并且在大约 1.04 亿年前，开花植物群落迅速多样化。 从沙滩到内陆河谷和洪泛区，各种环境都栖息着多种恐龙，其中鸭嘴龙、甲龙和各种兽脚类恐龙尤为常见。 人们主要通过它们在沉积物中留下的丰富脚印来了解这些动物。 - 骨头很少被保存下来。 加拿大地盾在萨斯喀彻温省和马尼托巴省北部形成了一片低洼地区，将沉积物向西流入海道。 我们发现，曾经有一个巨大的三角洲从东岸延伸出来，完全堵塞了航道。 不断上升的落基山脉使地壳向东凹陷约 1000 公里，形成了向西增厚的楔形沉积物。 由于沉积发生在浅水区和低洼的沿海平原上，即使海平面的微小变化也会导致海岸线位置发生横向移动，因为水会交替加深和变浅。 盆地沉降速度的变化也引起了古代海岸线位置的重大变化。 通过研究陆地、海岸线和近海沉积物的垂直连续和横向分布，可以推断出海岸线运动。 通过使用丰富的勘探钻孔数据绘制这些岩石类型的分布图，以及通过露头研究，可以重建盆地的地理演化过程，并评估海平面的相对影响（主要受气候变化控制） ），以及盆地地理上的沉降或隆升（受板块构造控制）。加拿大西部的白垩纪岩石不仅提供了动物、植物演化、海平面变化和造山的详细记录，而且还提供了丰富的自然景观资源，对全省经济具有重大利益。 沉积在海道中心的海洋泥岩含有藻类组织，这些藻类组织在热量、压力和时间的作用下产生天然气和石油，并在多孔的沙质海岸线沉积物中积累。地势低洼的沿海平原积累了厚厚的泥炭沉积物，这些泥炭沉积物后来压实成优质煤炭，这对于格兰德卡什和塔布勒岭等城镇具有重要的经济意义。