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？

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?