Earth’s mantle has been split by the Pacific Ring of Fire, revealing ancient clues about the formation and breakup of the supercontinent Pangaea, according to a recent study. The African domain, which covers most of Earth’s landmass, extends from Asia and Australia to Europe, Africa, and North America. In contrast, the Pacific domain encompasses the Pacific Ocean and has less diversity in its mantle isotopes compared to the African domain.
This split in the mantle reflects the formation and breakup of two supercontinents over the past billion years: Rodinia and Pangaea. During the assembly of these supercontinents, oceanic crust subducted under the continents, carrying elements and isotopes from the continental crust into the mantle. This process continued even after the breakup of Pangaea, leaving distinctive signatures in both the deep and shallow mantle.
The recent study, published in the journal Nature Geoscience, focused on shallow mantle magma samples from midocean ridges. By analyzing the elemental and isotopic compositions of these samples, researchers were able to identify distinct African and Pacific domains in the mantle. This research sheds light on the processes that connect the mantle to the surface of the Earth and can help geoscientists understand the mechanisms behind supercontinent breakup.
One key aspect of this research is the role of large low-shear velocity provinces (LLSVPs) in supercontinent breakup. These mantle “blobs” are located beneath the African and Pacific domains and are thought to play a role in the breakup of supercontinents. By studying these processes, scientists hope to better understand how elements essential for life, such as rare Earth elements, are cycled from deep within the Earth to the surface.
Plate tectonics, which are responsible for these processes, are unique to Earth among known planets. Understanding how these processes work can provide insights into the geological history of our planet and the conditions that support life. By studying the mantle’s composition and its connection to supercontinent formation and breakup, researchers can gain a better understanding of Earth’s dynamic geology and its impact on the development and sustainability of life on our planet.
