Jakarta –
Without us realizing it, the Earth’s plates continue to move. This movement is predicted to split a number of lands. Apart from Africa, mainland India is also said to be split in two.
A recent study suggests that the Indian Tectonic Plate may be undergoing horizontal separation, into two layers about 100 kilometers thick each. This is different from the vertical separation process that occurred in East Africa, where a new microcontinent was formed. For the split in India appears to have occurred horizontally when it met the Eurasian Tectonic Plate.
The Himalayas, as the largest mountain range in the world, have the main characteristic of the Tibetan Plateau behind them. The northward movement of India at a speed of 1-3 kilometers/year for 60 million years is recognized as the main driver of the formation of these mountains. However, the exact mechanism for the formation of the Himalayas and the Tibetan Plateau is still debated.
A number of theories try to explain this phenomenon. One theory is that the Indian Plate was too buoyant to sink into the mantle, so it slid under the Eurasian Plate and created the bulge that became the Tibetan Plateau. Another theory is that the Indian Plate stretched, like paper forced upright, with Tibet formed by a bulge.
As reported by IFLSCIENCE, Tuesday (12/3/24), last December, a third option was proposed at the American Geophysical Union Conference. According to this view, the Indian Plate is undergoing delamination. As a result, the upper part later peeled off to support Tibet, while the denser lower part sank into the mantle. The researchers suspect that the upper part of this floats, which is thick enough to account for the height of Tibet, while the lower part behaves like an oceanic plate forced beneath a continental plate.
“We didn’t know that continents could behave like this, and that, for solid earth science, is quite fundamental,” Professor Douwe van Hinsbergen of Utrecht University, who was not an author of the study, told Science Magazine.
The importance of this finding is highlighted by the fact that it is the first time a continent has been seen to delaminate, according to Professor Douwe van Hinsbergen of Utrecht University. Although it was impossible to drill to a depth of 100 kilometers to verify this idea, the researchers used clues from helium rising through springs in Tibet.
“This is the first time that it has been caught in action in a submerged plate,” van Hinsbergen told Science Magazine.
Helium-3, which is extremely rare on Earth and must have come from the planet’s formation, was found in high concentrations in several Tibetan springs. The researchers, led by Simon Klemperer of Stanford University, concluded that the mantle was close enough to the surface north of Tibet that helium-3 could reach the springs. However, further south, the leaking gas mainly contains helium-4, indicating that the plate has not yet split there and formed a barrier that helium cannot pass through. One exception is an area near Bhutan, where researchers suspect the mantle has penetrated the crust, creating strange signals.
Earthquake patterns in the region also support this hypothesis and indicate that the mantle intrusion originated from the eastern side of the plateau. The authors suggest that the shape of the Indian Plate, which is thicker in the north and thinner on the flanks, may have aided this process. With the center of the plate sinking more rapidly, even the relatively low pressure of the mantle material above the bottom of the plate can cause it to flake off.
Although understanding these geological processes still requires further research, these findings open the door to new insights into earth science, and simultaneously strengthen our understanding of how continents can experience profound changes over long geological time periods.
*This article was written by Fadhila Khairina Fachri, participant in the Merdeka Campus Certified Internship Program at detikcom.
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2024-03-12 01:42:41
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