Earth’s Mantle Could Be Harbouring Ocean of Magma Formed Billions of Years Ago, Claims Study

A new study published on March 26 in the Nature journal revealed that the magma ocean formation near Earth's core started around 4.4 billion years ago. It might be impacting the Earth today as odd mantle anomalies. Discoveries suggest that Earth inevitably sheltered a deep basal magma believed to have existed at the boundary between the mantle and core. This helped the scientists explain the baffling structure of the mantle, such as the Large Low-Velocity (LLVPS) discovered with the help of seismic imaging. This event has played a crucial role in Earth's shape with thermal and tectonic evolution.

Discovery and Implications

Assistant Professor Charles-Édouard Boukaré of York University, Toronto, who led this study, told Live Science that these magma oceans could affect thermal communication between the mantle and core, further affecting the tectonic plates' location.

A new model proposed by his team combines geochemical and seismic data to help researchers explore how early crystallisation could lead to the persistent molten layer formed deep inside the planet. Boukaré, James Badro, and Henri Samuel are affiliated with the French Research Institutions and played a major role in the study published in the Nature journal.

Formation of Basal Magma Ocean

The team discovered that the magma ocean formation is inevitable, irrespective of the direction of Earth's mantle solidification, either from core to surface or vice versa. In each case, the new Earth model proposes that dense iron oxide-rich solids sank near the Earth's core and remelted (iron has a low melting point) due to the high temperature and pressure conditions, causing a permanent ocean of magma. Boukaré emphasised that a basal melt would be formed despite the least conducive scenarios.

Lasting Effects and Geological Memory

This study shows that the deep magma ocean left a lasting imprint on the interior of Earth around a few hundred million years ago. In a statement given to the publication, Boukaré said that there is a memory, explaining that Earth's internal structure was shaped very early in the past and still plays a significant role in bringing geological processes such as tectonic movement and mantle convection. Dating back around 4.4 billion years, LLVPS may be the remnants of this ancient primordial layer.

Looking to Other Planets

Boukaré is seeking to expand the model with further trace elements and practice it on other planets made of rocks. He said that maybe this basal magma ocean event is not so unique to the Earth. This research could open new doors into comprehending the planetary formation across the solar system.