Researchers at the University of Southampton have published findings suggesting that a vast escarpment system formed approximately 800 million years ago during the breakup of the supercontinent Rodinia. The cliff formation may have extended thousands of kilometers across western North America, reaching heights of roughly one kilometer. Over extended periods, erosion along this immense rocky boundary gradually removed massive quantities of material, progressively exposing ancient crystalline basement rocks that are visible in the Grand Canyon today.
The Grand Canyon’s geological record spans about two billion years, yet more than half of that rock sequence appears to be absent from the visible layers. This gap, known as the Great Unconformity, represents a mysterious discontinuity spanning over a billion years. The research team proposes that the ancient escarpment crossed regions now comprising Arizona, Utah, Idaho, Wyoming, Colorado, Texas, Oklahoma, Arkansas, Missouri and Illinois.
To reconstruct the ancient landscape, the research team combined plate tectonic movement reconstructions with data on landscape evolution over time. When Rodinia was fragmenting, the future Grand Canyon location occupied a position relative to the continental edge comparable to major escarpments currently found in South Africa and Brazil. Over tens of millions of years, the giant cliff system would have gradually shifted inland as erosion diminished it. The researchers estimate this process may have removed as much as eight kilometers of rock in certain locations, consistent with geological evidence indicating that five to ten kilometers of rock disappeared from parts of the region before the modern Grand Canyon formed.
The influence of this escarpment may have extended across a broader region than the Grand Canyon itself. By creating a long-lived mountainous rim around western Laurentia, the ancient North American continental core, the landscape may have influenced river courses, determined sediment deposition zones, and affected marine transgressions before the Cambrian period. The research was conducted by scientists from the University of Southampton, GFZ Helmholtz Centre for Geosciences, University of Potsdam, and University of Illinois Urbana-Champaign, with findings published in the journal Geology.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI