Every geography textbook contains these maps: maps that look like the earth today, but not exactly because all the continents have been combined into one subcontinent. These cards were used to explain why dinosaurs were similar in South America and Africa, or North America and Europe.
“Paleogeographic” reconstructions provide such a context to examine the processes that have shaped our planet: the movement of plate tectonics on Earth, volcanoes, mountain formation and their interactions with the oceans, the atmosphere and the sun that shape climate and life . In the last 10 years software has been developed that anyone interested can use to carry out this reconstruction.
But if old maps are already in our elementary school books, what are geologists like me trying to reveal? Just the details? In a way, yes, working on the details of past plate movements can make a huge difference. For example, large ocean currents can suddenly change direction when they open or close a narrow sea route, for example between America or when water suddenly floods the Strait of Gibraltar and fills the Mediterranean Sea. Slight differences in the timing or location of these corridors may aid or distort what we believe caused climate change in the past.
But the biggest problem for ancient geography isn’t the details: it is that up to 70 percent of the earth’s crust, which “recently” existed 150-200 million years ago, when dinosaurs were already roaming the planet, was lost to be sink in. the inner mantle of the earth. On older maps, we usually filled in the now divided areas with broad brushstrokes, using the simplest scenarios without a lot of detail. But there are remnants of this sloping crust that remain in the geological records, and in my area of research we are trying to use these records to identify the “lost” surface of the earth.
Many mountains, the most famous of which is the Himalayas, are made up of folded and stacked segments of rock scraped from a split plate. The type of rock and the fossils and minerals it contains can tell us when and where these rocks were formed. Geologists can then figure out how these continents, deep basins, and volcanoes were connected in the distant past.
Over the past few years, when I’ve been explaining how we reconstruct ancient geography from modern mountains, I was sometimes asked if we could predict future mountains as well. I always say, “Sure, but why should I do this? I have to wait a hundred million years to see if I’m right. “
But then I realized that this could be an interesting thought experiment. Predicting the geometry of future mountains requires the formulation of a series of “mountain building rules” that have never been done before. And we must anticipate how the geography so well known to us will turn into a mountain belt that lets us see what forever-lost plates look like, especially pieces that have fused together without leaving any record. Are we going to make mountain belts very similar to ours? So we did it. I formulated the rules by comparing similarities in mountain belts. Thomas Scotten, then an MSc student, used the rules to predict the geoengineering of a mountain belt that would form over the next 200 million years if Somalia separated from Africa as predicted and collided with India.
The resulting mountain range, which we call the “Somali Mountains”, was probably the Himalayas of its time. A look at the parallels between Somalia and the mountains as they are known today can offer solutions that we may not have thought of about ancient geographic evolution.
According to our research, for example, a mountain belt could form in the bay between Madagascar and Africa, which would curve steeply like the Carpathian Mountains in Eastern Europe or the Banda Islands in Indonesia and Timor. Northwest India will be buried about 50 kilometers under Somalia, but then Somalia will reverse and northwest India will reappear – this is a geological story very similar to that of Western Norway about 400 million years ago.
Thought experiments like our observations in Somalia help us understand what we missed in reconstructing the history of the Earth’s plates and surface. The better this reconstruction, the better we can predict the history and behavior of the earth, its resources and the effects of their use.
(This story was not edited by Devdiscourse staff and is automatically generated from a shared feed.)
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