Unusual Blobs Detected Deep Within Earth in Surprising Locations

Waves rippling from Earth’s core provide valuable clues about its composition and the distribution of its materials.

Researchers from ETH Zurich and Caltech have used seismic waves to uncover unexpected chunks of Earth’s plates in surprising locations. For over a century, geologists have mapped Earth’s interior by analyzing how seismic signals travel at different speeds through various materials. However, traditional methods have been limited by computational constraints.

Using the Piz Daint supercomputer, the team processed data from all types of earthquake waves, creating a detailed map of the lower mantle. This revealed dense, cooler rock fragments resembling tectonic plates, far from known subduction zones. Some of these mysterious blobs, such as those beneath the western Pacific Ocean, appear misplaced based on geological history.

“Apparently, such zones in the Earth’s mantle are much more widespread than previously thought,” explains Thomas Schouten, an Earth scientist from ETH Zurich.

Diverse Origins of Mysterious Chunks in Earth Lower Mantle

Schouten suggests that these enigmatic chunks in the lower mantle may not all originate from tectonic subduction. Instead, they could have diverse origins, reflecting the complex history of Earth’s interior.

The seismic waves used for this study primarily reflect the speed at which they travel through Earth, providing only a partial picture. Schouten emphasizes the need to dig deeper into the material properties that influence wave speed.

“We need to calculate the different material parameters that could generate the observed wave speeds,” he explains. “These chunks might consist of ancient, silica-rich material that has survived for about 4 billion years since the mantle’s formation. Alternatively, they could be zones where iron-rich rocks have accumulated due to mantle convection over billions of years.”

For example, the shapes beneath the Pacific may be layers that separated from the plate’s base, which is thinner near the surface than expected.

To fully understand these mysterious formations, researchers will need to conduct further investigations. Each of these chunks likely holds unique insights into Earth’s dynamic history.

Read Original Article: Science Alert

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