The Grand Canyon’s rock record is missing 1.2 billion years of history

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Called “The Great Unconformity”, the Grand Canyon has a 1.2 billion year gap in the rock record. Above the gap is 500 million-year-old sandstone (Cambrian age), a time of billions of shelled marine creatures. Below the gap is metamorphic rock of the Slatherian period aged 1.75 billion years where no fossils exist at all. But…

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