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?

前寒武纪占已知地质时间的近87％，但在五十亿年前之前的地面景观和表面过程的可用信息取决于散落的岩石记录，通常暴露在偏远地区。河流沉积学代表了了解前寒武纪景观的物理和环境条件的重要工具，加拿大北极和北欧的广阔地区是研究前寒武纪河流岩石记录的理想游乐场。植物前河上的现有模型假设几乎所有流都是浅，宽，弱弯曲的，并且由浮华的径流主导。该假设与地球上现代植根的河流和火星上古老的河流景观的地貌形成对比。迄今为止，关于前寒武纪河流的许多基本问题仍未解决：前寒武纪河流与现代植被的河流相当，还是与周期外河流景观相提并论？前寒武纪河流是否随着时间的流逝而演变，以响应改变地球动力，环境和生物学强迫？在泛大陆集会和强烈的山区建筑期间，植被的河流在多大程度上与现代河流有所不同？