The Grand Canyon Is Missing 1.2 Billion Years of History, and Researchers May Finally Know Why - VICE

Over the years, as researchers have sifted through the Grand Canyon’s geological record, they noticed a big chunk of its history—about 1.2 billion years’ worth—has been missing all along. Entire layers of rock that should be there simply are not. New research might finally explain why.

This gigantic gap in the planet’s narrative is known as the “Great Unconformity.” Geologically speaking, it’s the equivalent of a history teacher detailing the American Revolution, and then jumping straight to, say, Obama’s election. Yes, two important parts of American history, but a lot of other important stuff happened in between.

Now, a series of recent studies is attempting to explain how a combination of geological phenomena contributed to that gigantic missing chunk of Grand Canyon history.

First, around 800 million years ago, the ancient supercontinent Rodinia started tearing itself apart. According to research in Geology, this continental rift left behind a towering, 6-mile-high cliff dubbed the “Great Escarpment of Laurentia.” For over 200 million years, relentless river erosion chewed away at this massive cliff, stripping off miles of surface rock long before ancient “Snowball Earth” glaciers finished the job.

Then came the planetary dynamic lift. A study in Nature found that movement in Earth’s mantle pushed the continental landmasses upward between 1 billion and 540 million years ago, exposing them to massive erosion. As the mantle currents shifted, the continents sank, letting rising oceans bury the newly shaved surface under fresh ocean sediment.

Those missing 1.2 billion years didn’t just vanish into thin air. To be more precise, they were ground up and washed away and submerged, like a planet trying to cover up evidence of its own evolution. A planet ground them up, washed them away, and submerged them, spending hundreds of millions of years destroying its own evidence.