Precambrian fluvial rocks of Arctic Canada, and their analogies to modern unvegetated rivers and extra-terrestrial fluvial landscapes

加拿大北极地区的前寒武纪河流岩石及其与现代无植被河流和地外河流景观的类比

• 批准号: RGPIN-2016-05720
• 负责人: Ielpi, Alessandro
• 金额: $ 1.99万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633796
• 关键词: Precambrian; fluvial; rocks; Arctic; Canada

The Precambrian represents almost 87% of known geological time, yet available information on terrestrial landscapes and surface processes before half a billion year ago depends on a scattered rock record, often exposed in remote locations. Fluvial sedimentology represents a prominent tool to understand the physical and environmental conditions of Precambrian landscapes, and vast regions of Arctic Canada and northern Europe represent the ideal playground to investigate the Precambrian fluvial rock record. Existing models on pre-vegetation rivers assume that virtually all streams were shallow, wide, weakly sinuous, and dominated by flashy runoff. This hypothesis contrasts with the varied geomorphology of modern unvegetated rivers on Earth and ancient fluvial landscapes on Mars. To date, a number of essential questions on Precambrian rivers remain unresolved: were Precambrian rivers comparable to modern unvegetated ones, or to extra-terrestrial fluvial landscapes? Did Precambrian rivers evolve through time in response to changing geodynamic, environmental, and biological forcing? And to what extent did unvegetated rivers differ from modern ones during periods of pan-continental assembly and intense mountain building?

前寒武纪代表了近87%的已知地质时间，但有关5亿年前陆地景观和表面过程的可用信息取决于分散的岩石记录，通常暴露在偏远地区。河流沉积学是了解前寒武纪景观的物理和环境条件的重要工具，加拿大北极和北方欧洲的广大地区是研究前寒武纪河流岩石记录的理想场所。现有的模型对前植被河流假设，几乎所有的流浅，宽，弱弯曲，并占主导地位的闪光径流。这一假设与地球上现代无植被河流和火星上古代河流景观的各种地貌形成了对比。到目前为止，一些关于前寒武纪河流的基本问题仍然没有解决：前寒武纪河流与现代无植被河流相比，还是与外星河流景观相比？前寒武纪河流的演化是随着地球动力学、环境和生物强迫的变化而变化的吗？在泛大陆聚合和剧烈造山时期，没有植被的河流与现代河流有什么不同？