For millions of years, geologists puzzled over a gaping hole in Earth's history. A massive chunk of the planet's crust, spanning from Canada to Siberia, mysteriously vanished around 700 million years ago. Theories swirled, suggesting catastrophic collisions, ancient supercontinents breaking apart, and even extraterrestrial intervention. But thanks to recent research, the secrets of Earth's missing crust are finally starting to come to light.
The missing piece, known as the Great Unconformity, is a stark gap in the geological record. Below it lie rocks billions of years old, while above it rests much younger sediment. This abrupt discontinuity hinted at a major event causing large-scale erosion and removal of the missing crust.
Two main culprits have emerged as the likely suspects:
Snowball Earth: Around 700 million years ago, Earth experienced a series of global glaciations, potentially plunging the entire planet into a "Snowball Earth" state. These massive ice sheets, grinding across the continents, could have scoured away rock at an incredible rate, explaining the missing crust.
Rodinia's Breakup:
The supercontinent Rodinia, which existed some 1 billion years ago, began breaking apart around 750 million years ago. This colossal continental rift would have triggered tremendous tectonic activity, including mountain building and widespread erosion. This, combined with Snowball Earth glaciation, could have been the perfect recipe for erasing a sizeable chunk of Earth's crust.
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