The Earth's Inner Mantle Has Led In The Destruction Of Up To 70% Of The Earth's Crust

Maps that resemble today's earth, but aren't quite, because all continents have been united into a single supercontinent. These maps were used to explain why South American and African dinosaurs, as well as North American and European dinosaurs, appeared so similar.

Figuring out the finer points of plate motions in the distant past could make all the difference. When narrow maritime corridors open or close, such as between the Americas or when water flowed through the Straits of Gibraltar and filled up the Mediterranean, significant ocean currents can abruptly alter course. Subtle discrepancies in the timing or location of such corridors may support or refute our theories about what caused historical climatic changes.

While it's not the specifics that are the most difficult for paleogeographers to solve: Subduction into the Earth's inner mantle has resulted in the loss of up to 70% of the Earth's crust that existed as recently as 150-200 million years ago, when dinosaurs roamed the world. Their needs were filled in those now-subducted locations on paleogeographic maps with broad brushstrokes and therefore the simplest feasible scenarios without much information.

However, vestiges of this subducted crust have been found in the geological record, and in my field of study, we are attempting to use these records to understand more about Earth's 'lost' surface.

Paleogeographic reconstructions such as this provide context for studying the processes that create the planet: plate tectonics, volcanism, and mountain building, as well as their interactions with the oceans, atmosphere, and sun, which determine climate and life. Software has been developed in the last ten years that allows anyone who is interested to perform these reconstructions.

Many mountains, including the Himalayas, are composed of folded and layered rock slices scraped off the subducted plate. The types of rock, as well as the fossils and minerals found inside them, can help us determine when and where these rocks formed.

After that, geologists can piece together how those continents, deep basins, and volcanoes interacted in the distant past.

Furthermore explaining how they reconstruct paleogeography from modern mountain ranges in recent years and was frequently asked if they might also anticipate future mountains.

But then it occurred to me that this could be a fun thought experiment. Predicting future mountain range design would necessitate the creation of a set of 'laws of mountain building,' which had never been done before.

And they would have to estimate how the familiar terrain would evolve into mountain belts, allowing us to imagine what the plates that were gone forever, particularly the parts that subducted without leaving a record, could have looked like. The question arises that they would be able to make mountain belts that appear similar to the ones now they have.

So that's they came up with the rules by comparing which characteristics are widespread in mountain belts. Thomas Schouten, my then-MSc student, utilised the rules to predict the geological architecture of a mountain belt that will build in the next 200 million years if Somalia breaks away from Africa and collides with India, as predicted.

The ensuing mountain range, which they dubbed the 'Somalaya mountains,' could have been the Himalayas of the time. And observing such similarities between the Somalaya and today's mountains can lead to paleogeographic evolution answers they hadn't considered before.

According to our findings, a mountain belt could grow in the gulf between Madagascar and Africa, with a strong curving shape similar to the Carpathians of Eastern Europe or the Banda islands of Indonesia and Timor.

Experiments like our examination at the Somalayas let us see what we're missing when reconstructing the Earth's plate and surface history. The more accurate those reconstructions are, the better we will be able to forecast Earth's history and behaviour, as well as its resources and the consequences of their use.