Earth's rocks have a missing layer spanning up to a billion years. Scientists finally know what happened to it
The 'Great Unconformity' has puzzled scientists since its discovery in the 1870s
Scientists have discovered the answer to a geological mystery that has puzzled them for over a century – the missing layer of Earth's rocks known as the Great Unconformity. This gap, spanning up to a billion years, puzzled geologists since its discovery in the 1870s. The missing layer, which spans from two to four billion years old, is sandwiched between younger sedimentary layers, indicating a significant period of geological activity that has until now remained a mystery.
A team of scientists used advanced computer modeling to reveal that deep processes within the Earth's mantle, specifically slow convection, caused ancient continental blocks to be lifted up and down over a period of a billion years. As these blocks were uplifted, the crystalline underlayer was exposed and the sedimentary layers on top were eroded away.
When the blocks sank, new layers of sediment began to form, which are now preserved in the rock. This research suggests that the missing pages in Earth's geological archive were caused by the slow movement of the mantle, which gently lifted and lowered entire continents, leaving a distinct mark on the geological record.
Written by urgent.news from Scientific American's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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