By firing more lasers than a human hair at small grains of ore extracted from the beach sand, researchers have found a piece of the earth’s crust nearly four billion years old beneath South Western Australia.
The discovery has the potential to help explain the planet’s evolution from uninhabitable to vital, according to project leader Maximilian Droellner.
The doctoral student at Curtin University says the lasers were used to vaporize portions of individual zircon grains.
This revealed where they originally eroded and, in the process, a view of the geological history of the region.
“There is evidence that a piece of crust up to about four billion years the size of Ireland has been influencing WA’s geological evolution over the last billion years,” Droellner said. .
It is believed that the ancient part of the planetary shell has survived multiple mountain-building events between Australia, India and Antarctica, and is located tens of miles underground.
“When we compare our findings with existing data, it appears that many regions of the world experienced a similar time of early crust formation and preservation,” Droellner said.
“This suggests a significant change in the evolution of the earth about four billion years ago, as meteorite bombardment subsided, the crust stabilized and life on earth began to settle. “.
According to previous studies, part of the research region known as the Yilgarn Craton retains part of the oldest continental crust on the planet and is home to the oldest terrestrial minerals on Earth.
Although much of the original geological record is lost due to erosion, durable minerals such as zircon form sediments that draw a vivid picture of the planet’s history, according to research supervisor Milo Barham of the Mineral Systems Group. Curtin.
There are clues about the development of a habitable biosphere, the evolution of continents, and the accumulation of mineral resources at the boundaries of ancient plates.
Billions of years of earth’s history are etched into the geology of each grain and the work your team is doing is helping to unblock that information, Dr. Barham says.
“Studying primitive earth is a challenge given the sheer amount of time that has elapsed, but it is of great importance to understand the importance of life … and our quest to find it on other planets.”
The WA crust piece also appears to define an economically important boundary aligned with iron ore and gold deposits.