Earth Is Missing a Billion Years of History. We Finally Know Why - ZME Science
Geologists are investigating the 'Great Unconformity,' a massive gap in Earth's rock record spanning up to a billion years. New research suggests that tectonic activity related to supercontinent cycles, rather than 'Snowball Earth' glaciation, is the primary cause.
Why it matters
Understanding this geological mystery provides critical insight into the evolution of Earth's crust and the environmental conditions that shaped the modern planet.
When geologist John Wesley Powell explored the Grand Canyon in 1869, he noticed a glaring omission in the rocks. A layer of rock just 520 million years old sat directly on top of ancient rock dating back 1.4 to 1.8 billion years. Somewhere in between, up to a billion years of Earth’s history had vanished.
Scientists call this massive gap in Earth’s geological history the Great Unconformity. It appears not just in North America, but all over the planet. The missing layers represent anywhere from several million to over a billion years of time.
“There’s more than a billion years that’s gone,” said Barra Peak, co-author of a 2021 study on this puzzling gap in Earth’s history. “It’s also a billion years during an interesting part of Earth’s history where the planet is transitioning from an older setting to the modern Earth we know today”.
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