The Indian and Asian continental plates crashed and formed the world's largest and highest geologic structures: the Himalayan Mountains and the Tibetan Plateau.
Despite the importance of these formations, which influence the global climate through atmospheric circulation and seasonal monsoons, experts have differing theories about how tectonic plates below the surface created them. Scientists have mapped the boundary between the Indian and Asian continental plates using the data from the hot springs. The current issue of the Proceedings of the National Academy of Sciences contains findings that have implications for mineral formation.
Simon Klemperer is a senior study author at the School of Earth, Energy and Environmental Sciences.
Klemperer traveled to Tibet and India to collect samples to support his theory that chemicals bubbling to the surface could be used to understand what is happening 50 miles below. About the distance from Canada to Mexico in the western U.S., he and his colleagues tracked down remote geothermal springs.
The study authors used noble gas helium to determine which springs came from each plate. The Asian plate had a different signature for the gas that came from the hot mantle. The colder plate is only detected in the south, beneath the Himalayas, while India is no longer touching Tibet above it by a wedge of hot mantle. The results show that the old theory that the Indian plate lies beneath Tibet is no longer valid.
It is amazing that we have a well-defined boundary just a few kilometers wide above a plate boundary that is 100 kilometers deep, Klemperer said.
Subduction vs. collision.
When a heavier plate dives under a continental plate, material in the subsurface is recycled into the Earth's mantle. The Ring of Fire is home to frequent earthquakes and active volcanoes.
Researchers theorize that the subduction of ocean crust caused the two continents to collide, closing up the subduction zone for mountain building. There is a possibility that the continental crust is releasing fluids and melting, just as it would happen in the ocean.
Klemperer said that continental collision and oceanic subduction should be looked at the same way.
The sea change is related totonic sea change.
The theory of plate tectonics changed the Earth sciences by showing how plates drift apart and cause eruptions. Researchers don't understand why plates move the way they do.
Klemperer said the new findings add an important element of understanding, with potential ramifications about what controls the convection that drives plate tectonics. The Indian plate diving into the mantle changes the way we understand how elements and rock types are distributed on the Earth.
The study builds on previous research in which Klemperer and his colleagues imaged the Himalaya collision zone using seismic data and found that as the Indian tectonic plate moves from the south, the thickest and strongest part of the plate dips beneath the Tibetan plateau and causes tears in the Indian plate. The hot springs had the same location as those tears.
We have to figure out how to put them together because we are seeing the same processes through different lens.
There are implications for minerals.
Since the Spaniards conquered South America in search of gold, civilizations have known about the rich mineral deposits in places like the Andes Mountains, which are part of the Ring of Fire. It is difficult to explain the rich mineral province of Southern Tibet, with gold, copper, lead, zinc and other deposits.
If it looks like the old model, but we know it did happen because we have all these minerals in Tibet.
As the only active continental collision on our planet, the Himalayas and Tibet offer a glimpse into how other mountain ranges have formed in the past and may form in the future.
Klemperer said that Australia is just beginning to collide with the Indonesian block.
A co-author on the study is a PhD student named Tianze Liu. The Chinese Academy of Sciences is one of the co-authors.
More information: Limited underthrusting of India below Tibet: He/He analysis of thermal springs locates the mantle suture in continental collision, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2113877119. Journal information: Proceedings of the National Academy of Sciences Citation: Hot springs reveal where continental plates collide beneath Tibet (2022, March 14) retrieved 14 March 2022 from https://phys.org/news/2022-03-hot-reveal-continental-plates-collide.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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