Earth’s rocks have a missing layer spanning up to a billion years. We finally know where it went
The Great Unconformity is a mysterious gap of hundreds of millions of years in Earth’s geological history – and new research may have finally explained it.
Geologists long puzzled over the missing chapters in Earth's geological record, known as the Great Unconformity. This gap, spanning up to a billion years, appears abruptly in rock layers around the world, where younger sedimentary layers sit directly atop much older crystalline basement rock. To unravel this mystery, researchers at the University of Wollongong used supercomputing power to simulate how the mantle beneath Earth's surface moves and deforms over millions of years.
Their findings show that the uplift and subsequent erosion of ancient continental blocks by massive ice sheets during the Snowball Earth period could explain the formation of the Great Unconformity. As these blocks were lifted by mantle convection, the sedimentary layers above were eroded away, leaving a clean surface. When the crust subsided, new sediment layers began to accumulate, forming the younger rock layers we see today.
This process, known as mantle-driven uplift and erosion, provides a compelling explanation for the missing layers in Earth's geological history.
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