'Earth's mantle was torn apart': New study unveils dark secrets of Pangaea's split

A recent study has unveiled that Earth's mantle is divided into two distinct sections, a phenomenon linked to the formation and subsequent breakup of the ancient supercontinent Pangaea. This groundbreaking research highlights the contrasting characteristics of the mantle beneath the African and Pacific domains, shedding light on the geological processes that have shaped our planet over billions of years.

The African domain, which encompasses a vast area from the east coast of Asia and Australia across Europe and Africa to the west coast of North America, contains a rich diversity of elements and isotopes. In contrast, the Pacific domain, which primarily covers the Pacific Ocean, exhibits far less variability.

The study's co-author, Luc Doucet, a senior research fellow in Earth and planetary sciences at Curtin University in Australia, explained that these differences reflect the planet's last two supercontinent cycles over the past billion years, particularly focusing on Rodinia and Pangaea.

Doucet noted that the geological history of these supercontinents played a crucial role in shaping the mantle's composition. As the continents came together, oceanic crust was subducted beneath them, dragging elements from the continental crust into the mantle. This process, known as subduction, has contributed to the current concentration of materials beneath the African domain.

Even after the breakup of Pangaea approximately 200 million years ago, the signatures of these geological processes persisted in both the deep and shallow mantle. The researchers analyzed 3,983 samples of basalt from midocean ridges, where tectonic plates spread apart and magma from the shallow mantle solidifies into volcanic rock. Using machine learning, they compared the elemental and isotopic compositions of basalts from different global locations and time periods, confirming the split between the African and Pacific mantle domains.

The study, published in the journal Nature Geoscience, also explores the ongoing dynamics within the mantle. It suggests that the breakup of supercontinents may be influenced by large low-shear velocity provinces (LLSVPs) deep within the Earth, often referred to as mantle "blobs." Doucet emphasized that understanding these processes not only clarifies the connection between the mantle and the Earth's surface but could also lead to insights regarding the concentration of valuable materials like rare Earth elements.

As the only planet known to possess plate tectonics, Earth continues to intrigue scientists seeking to unravel the complexities of its geological history and the implications for life on our planet.