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

前寒武纪代表了几乎87%的已知地质时间，然而关于5亿年前陆地景观和地表过程的现有信息依赖于分散的岩石记录，通常暴露在偏远地区。河流沉积学是了解前寒武纪地貌物理和环境条件的重要工具，加拿大北极和北欧的广大地区是研究前寒武纪河流沉积岩记录的理想场所。现有的植被前河流模型假定，几乎所有的河流都是浅、宽、弱曲折的，并以闪闪发光的径流为主。这一假设与地球上现代无植物河流和火星上古老的河流景观的不同地貌形成了鲜明对比。到目前为止，关于前寒武纪河流的一些基本问题仍然没有解决：前寒武纪河流可与现代无植物河流相比，还是可与地外河流景观相媲美？前寒武纪河流是否随着地球动力、环境和生物强迫的变化而随时间演变？在泛大陆集结和密集的造山时期，没有植被的河流与现代河流有多大的不同？ 要回答这些问题，需要在全世界范围内对前寒武纪河流岩石记录进行评估，并对证明了水文循环的陆地和地外区域的无植物河流景观进行广泛的遥感。这项研究建议旨在介绍：关于北极加拿大和北欧未被勘探的沉积盆地的更高水平的地质知识；关于火星和泰坦上河流河道地貌的创新数据库；现代无植物河流的沉积模型；以及最后，前寒武纪、现代无植物河流和地外河流沉积动力学的关键比较。该研究提案涉及2个实地项目和2个遥感项目，并将涉及几名本科生和研究生的指导。与联邦、地区和国际地质调查局以及几所加拿大和欧洲大学的合作正在进行中或正在发展中。这项研究的结果将被证明是现代科学的几个新兴方面的基础，特别是行星地质学和河流资源管理。

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? Answering these questions requires a worldwide assessment of the Precambrian fluvial rock record, and the extensive remote sensing of unvegetated fluvial landscapes on terrestrial and extra-terrestrial realms with demonstrated hydrologic cycles. This research proposal aims to introduce: a higher level of geological knowledge on under-explored sedimentary basins of Arctic Canada and northern Europe; an innovative database on the geomorphology of fluvial channels on Mars and Titan; a depositional model for modern unvegetated rivers; and finally, a critical comparison between the depositional dynamics of Precambrian, modern-unvegetated, and extra-terrestrial rivers. The research proposal is articulated on 2 field-based projects, and 2 remote-sensing-based projects, and will involve the supervision of several undergraduate and graduate students. Collaboration with federal, territorial, and international geological surveys and several Canadian and European universities is ongoing or in development. The outcomes of this research will prove fundamental for several emerging aspects of modern science, particularly planetary geology and river-resource management.