Rocks dug from beneath Earth’s crust could reveal secrets of planet’s origins
A Record-breaking recovery of rocks that originated deep in Earth could reveal secrets of the planet’s history, new research suggests.
Scientists have recovered the first long section of rocks that originated in the Earth’s mantle, the layer below the crust and the planet’s largest component.
At a nearly continuous 1,268 metres, the depth to which the researchers penetrated the mantle rocks beats the previous deepest hole (200 metres) by more than six times, they say.
The researchers suggest the rocks recovered from the mantle bear a closer resemblance to those that were present on early Earth rather than the more common rocks that make up the continents today.
The rocks will help to explain what role the mantle played in the origins of life on Earth, and the volcanic activity generated when it melts.
According to the team, which includes researchers from Cardiff University, the sample will also help to shed light on how the mantle drives the global cycles of important elements such as carbon and hydrogen.
The rock was recovered from a tectonic window, a section of the seabed where rocks from the mantle were exposed along the
Mid-atlantic Ridge, during Expedition 399 “Building Blocks of Life, Atlantis Massif” of the ocean drilling vessel JOIDES Resolution in Spring 2023.
Lead author Professor Johan Lissenberg from Cardiff
University’s School of Earth and Environmental Sciences, said: “When we recovered the rocks last year, it was a major achievement in the history of the Earth sciences, but, more than that, its value is in what the cores of mantle rocks could tell us about the makeup and evolution of our planet.
“Our study begins to look at the composition of the mantle by documenting the mineralogy of the recovered rocks, as well as their chemical makeup.”
With attempts dating back to the early 1960s, the recovery was led by the International Ocean Discovery Programme, an international marine research group of more than 20 countries that retrieves cores – cylindrical samples of sediment and rock – from the ocean floor to study Earth’s history.
Since then, the expedition team has been compiling an inventory of the recovered mantle rocks.
The findings are presented in the journal Science.
Dr Susan Q Lang, expedition scientist, an associate scientist in geology and geophysics at the Woods Hole Oceanographic Institution, said: “Analysing them gives us a critical view into the chemical and physical environments that would have been present early in Earth’s history, and that could have provided a consistent source of fuel and favourable conditions over geologically long timeframes to have hosted the earliest forms of life.”