A recent study presented at the Lunar and Planetary Science Conference in Texas proposes a link between Earth’s moon-forming cataclysm and the onset of plate tectonics. The widely accepted explanation for the formation of the moon suggests that a Mars-sized planet named Theia collided with Earth, and the debris from the collision later formed into the moon. The study suggests that remnants of Theia deep inside the Earth could have triggered subduction, a process that characterizes modern plate tectonics.

Moon-forming Cataclysm and Plate Tectonics

Plate tectonics is the process by which the Earth’s crust is divided into several plates that move around on the mantle beneath. It is a vital process that shapes the Earth’s surface and plays a crucial role in many geological phenomena such as earthquakes, volcanic eruptions, and the formation of mountains. However, despite its importance, the origins of plate tectonics are still largely unknown.

The new hypothesis proposes that two large, continent-sized blobs of material in the Earth’s lower mantle, known as large low-shear velocity provinces, could be the remnants of Theia. According to the simulations, once the hot alien blobs had sunk to the bottom of the mantle, they could have compelled large plumes of warm rock to upwell and wedge into Earth’s rigid outer layer, triggering the onset of subduction about 200 million years after the moon’s formation.

While the simulations suggest a plausible link between Theia and plate tectonics, there is still much debate on the origin of these low-shear velocity provinces. Geodynamicist Laurent Montési of the University of Maryland in College Park notes that these features are a recent discovery, and their origin is largely unknown. Therefore, it is too early to say definitively that Theia triggered plate tectonics.

The Unknown Origin of Large Low-Shear Velocity Provinces

However, if the link is confirmed, it could have important implications for the search for other Earth-like worlds. Earth is currently the only known planet confirmed to have plate tectonics. Therefore, understanding the origin of plate tectonics could help in identifying other planets with tectonic activity. “If you have a large moon, you likely have a large impactor,” says geodynamicist Qian Yuan of Caltech. Thus, searching for exomoons could be a key factor in discovering other tectonically active planets.

Despite the promising implications of the study, there is still much to be done to confirm the link between Theia and plate tectonics. However, the new hypothesis adds to the growing body of knowledge regarding the formation and evolution of the Earth, and it highlights the importance of continued research in this area. Understanding plate tectonics is not only crucial in learning about the history of our planet but also in discovering other Earth-like worlds that may harbor life.