A lost mega-cliff may explain the Grand Canyon’s missing billion years
A colossal cliff system created as the supercontinent Rodinia broke apart may have exposed the heart of the Grand Canyon nearly a billion years before the Colorado River carved it. The ancient landscape could also help explain why enormous sections of North America’s geological record appear to be missing.
Researchers from the University of Southampton and other institutions have discovered evidence of a massive ancient cliff system that may have exposed the deepest rocks in the Grand Canyon about a billion years before the Colorado River began carving the landscape. Led by Professor Thomas Gernon, the study suggests that this great escarpment formed around 800 million years ago as the supercontinent Rodinia broke apart.
The cliffs, estimated to have reached up to a kilometer in height and stretch for thousands of kilometers, helped expose ancient crystalline basement rocks in the Grand Canyon. These rocks, normally hidden by younger layers, now provide a glimpse into the geological history of the region that spans nearly two billion years. The findings also shed light on the mysterious "Great Unconformity," a billion-year gap in the rock record.
The research involved scientists from various institutions in the UK, Germany, and the USA, who combined plate tectonic reconstructions with data on landscape evolution to reconstruct the ancient landscape. They propose that the escarpment crossed regions that now include Arizona, Utah, Idaho, Wyoming, Colorado, Texas, Oklahoma, Arkansas, Missouri, and Illinois.
The escarpment's long-lasting influence may have shaped the mountainous terrain and river paths, contributing to the dramatic erosion observed in the Grand Canyon and other regions.
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