Lost 'mega-escarpment' across ancient USA may explain Grand Canyon's missing billion years
Scientists have found evidence that a colossal cliff stretching thousands of kilometers across ancient North America may have exposed the heart of the Grand Canyon nearly a billion years before it was carved by the Colorado River.
Scientists have discovered evidence of a massive cliff system stretching across ancient North America that may have exposed the Grand Canyon's core nearly a billion years before the Colorado River carved it. Led by the University of Southampton in the UK, the study suggests a 1-kilometer-high escarpment formed when the supercontinent Rodinia broke apart 800 million years ago.
This immense cliff system, which extended through much of western North America, contributed to the erosion of vast rock volumes and exposed ancient crystalline basement rocks now found at the Grand Canyon in southern Arizona. The findings help explain the missing half of the Grand Canyon's 2 billion-year geological record and shed light on the formation of the Great Unconformity, a billion-year-long gap in the rock record.
The study, published in Geology, combines plate tectonic reconstructions with landscape evolution data to recreate western North America's evolution as Rodinia fragmented. The ancient escarpment is believed to have stripped away up to 8 kilometers (5 miles) of rock in places, creating steep slopes and high ground that rivers and glaciers could readily erode.
This tectonic landscape may have also influenced river flow, sediment accumulation, and the timing of rising seas, impacting the evolution of complex life on Earth.
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