Deep fracture in Earth's mantle created by an unexpected occurrence under India

The Indian tectonic plate is undergoing an unexpected shift under Tibet. According to a study, this plate is splitting into two. This plate, along with the Eurasian plate, crashed into each other millions of years ago, forming the Himalayas and the Tibetan plateau. But the geological process and the tectonic interaction between the Indian and Eurasian plates have remained somewhat of a mystery. However, a study presented at the 2023 American Geophysical Union conference gives a clearer picture of Earth’s deep geological activity and an unexpected occurrence. For years, it has been believed that the Indian plate is sliding beneath the Eurasian plate. This continental collision started millions of years ago. The Eurasian plate is being pushed upwards. But recent discovery shows that that's not all that's happening. The Lower part of the Indian plate is peeling off and sinking into the mantle.

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A deep fracture has been observed in Earth's mantle

This process is known as "delamination". The lower part of the Indian plate is extremely dense and is peeling off. This process is supported by evidence, such as unusual patterns in earthquake waves and the detection of helium isotopes in Tibetan springs. These discoveries indicate that the fractures are reaching deep into the plate, leading to the gases being released from the mantle. There is also seismic data that supports the theory that the Indian plate isn't breaking apart in a single block, but is breaking apart under Tibet.

Study to understand tectonic movement

The collision between the two plates started 60 million years ago and continues to date. The delamination of the Indian plate shows how tectonic forces work under the Earth, showing how the larger mechanism continues to remain a mystery. The study utilised data from 94 seismic stations across southern Tibet to understand the tectonic activity. Both “up-and-down” S-wave and “back-and-forth” P-wave data were studied, as these seismic waves offer crucial insight into the composition and movement of tectonic plates. This was combined with previous data to create a model which showed that delamination was occurring under Tibet. So now what we have is a series of fractures that extend deep into the Earth’s crust.

Understanding how the tectonic plates work could help predict earthquakes, helping with preparedness and other measures, since scientists may be able to identify high-risk areas.