Revelations about ancient diamonds give clues about Earth’s origins

Scientists have discovered ancient diamonds which have provided new clues about the Earth’s evolution.

Researchers discovered ancient superdeep diamonds, which hail from mines in Brazil and Western Africa, were forged between 650 and 450 million years ago, at the base of the supercontinent Gondwana.

The discovery, made by an international team of experts, sheds light on the evolution and movement of Earth’s continents during the early stages of complex life.

Diamonds, due to their extraordinary resilience, can serve as records of ancient cycles of the creation and destruction of continents.

Dr Karen Smit, of the Wits School of Geosciences, said the diamonds are “extremely rare.” She explained that a team of experts sought to use the diamonds to understand how the earliest continents formed.

“We now know that they can tell us a lot about the entire process of continent formation,” she said.

The study involved dating the tiny silicate and sulphide inclusions within the diamonds to determine how they formed beneath the Gondwana supercontinent.

By doing so, scientists discovered a previously unknown geological phenomenon, revealing how modern day continents may have been formed.

“Diamonds formed at great depths beneath Gondwana when the supercontinent covered the South Pole, between 650–450 million years ago,” Dr Smit revealed.

She said the rocks hosting the diamonds became buoyant during the diamond formation process, carrying subducted mantle material along with the diamonds.

The material was then integrated into the base of the Gondwana supercontinent, effectively contributing to its growth from below and subsequent fragmentation to create new continents.

“Approximately 120 million years ago, Gondwana commenced its fragmentation, ultimately giving rise to the present-day oceans, including the Atlantic. Some 90 million years ago, the diamonds, bearing tiny inclusions of the host rock, were brought to the Earth’s surface through violent volcanic eruptions,” Dr Smit said.

The contemporary locations of these volcanic eruptions are situated on the fragmented continents of Brazil and Western Africa, two significant components of the former Gondwana supercontinent.

This indicates that the rare diamonds moved along different parts of the ancient supercontinent as it disintegrated, effectively “glued” to its base, according to the researchers.

“This intricate history of the diamonds underscores their extensive travels, both vertically and horizontally, within the Earth. They provide insights into the formation of the supercontinent and its later stages of evolution. This suggests a potential new mode of continent growth, where relatively young material fuses and consolidates these age-old continental fragments,” Dr Smit added.

The research has implications for our understanding of the role the evolution and movement of continents played in fostering life on Earth, according to Dr Smit.

“We need this type of research to understand how continents evolve and move. Without continents, there wouldn’t be life. This research gives us insight into how continents form and how life evolved, ultimately highlighting what makes our planet, Earth, unique among celestial bodies,” she said.