Scientists Crack Mystery Behind Large Slabs of the Earth's Crust That Went 'Missing' From Geological Records

The Earth is no simple planet, constantly shifting and molding itself over millions of years. Scientists have long studied the planet’s geological history, unraveling iconic changes, from the origin of huge mountain ranges to the disappearance of entire landmasses. One of the most confusing mysteries in geology has been 'The Great Unconformity,' a phenomenon where massive sections of Earth’s crust appear to be missing from the geological record, according to Indy 100. First identified in 1869 in the Grand Canyon, this puzzle has led researchers on a relentless journey to discover the fate of these lost slabs of rock. A breakthrough discovery finally solved the mystery—scientists have found where the major chunk of the missing Earth’s crust has gone.

Studies have revealed that the MIA crust was likely stripped away by major glacial erosion during a period known as "Snowball Earth," when the planet was almost entirely shrouded in ice. This huge geological event resulted in a massive change in the age of rocks, as older layers were eroded and replaced by younger sediment. The scale of this erosion is whooping high, with researchers estimating that around 1 billion cubic kilometers (200 million cubic miles) of pre-Cambrian material was lost. Lead author Andreas Petersson remarked, "Understanding how continents formed helps us understand why ours is the only planet in the solar system with life on it…Because without fixed continents and water in between them, we wouldn't be here. Indeed, continents influence both ocean currents and climate, which are crucial for life on Earth," stated Live Science.

But the question is where did all this lost material go? According to scientists, the answer lies in the dark abyss of the ocean. As glaciers eroded the sedimentary rocks, the material was carried into the sea, where it settled and contributed to the formation of new geological structures. A study analyzed river crystals in Finland, which further cemented their beliefs. Researchers discovered traces of a hidden chunk of Earth’s crust in Finland’s ancient riverbeds, revealing a crucial link between Europe and Greenland. Petersson asserted, "The zircon crystals we found in river sand and rocks from Finland have signatures that point towards them being much older than anything ever found in Scandinavia while matching the age of Greenlandic rock samples…At the same time, the results of three independent isotope analyses confirm that Scandinavia's bedrock was most likely linked to Greenland," stated Live Science.

This discovery is groundbreaking because it explains not only the disappearance of vast portions of Earth’s crust but also the origins of Scandinavia. The study suggests that part of the Fennoscandian Shield, a super old section of the Earth's crust, broke away from Greenland and migrated for hundreds of millions of years before settling in its current location. Geologist Tod Waight explains,  "Earth was probably a watery planet, like in the movie 'Waterworld,' but without any oxygen in the atmosphere and without emergent crust. But, because that's so far back in time, we can't be really be sure about what it actually looked like…Our study provides us with another important clue in the mystery of how continents formed and spread across Earth — especially in the case of the Fennoscandian Shield,” as reported by Live Science.

The missing crust is believed to have been forced underground, challenging long-held geological beliefs. Another researcher,  David Rowley explains, "We really have significant amounts of crust that have disappeared from the crustal reservoir, and the only place that it can go is into the mantle…And they can then be re-extracted and seen in some of those volcanic materials that come out of the mantle today," via Science Alert.