Moodies-BASE drills through millions of years
BARBERTON - At the end of 2021, geologists from around the world were drilling into the Earth in various spots around the Makhonjwa Mountains in an effort to discover more information of this planet’s early history.
Led by Prof Christoph Heubeck of Jena University, Germany, the Moodies-BASE Drilling Project’s base of operations was set up in the heart of Barberton, and the drilling expeditions were finished by July 2022.
Barberton’s Makhonjwa Mountains, which are older than three billion years, are one of the two places in the world where the oldest well-preserved rocks are found. They provide much sought-after information about the surface conditions of early Earth and under what conditions bacterial life spread.
On Wednesday evening, February 28, Heubeck held the 36th Alex du Toit Lecture at the Lone Tree Shell Hole in town, where he presented on the team’s work, its objectives and the drilling project’s progress now that the core samples are being examined at universities across the world.
The project had also been co-ordinated by Prof Nic Beukes of the University of Johannesburg, who passed away early last year.
The team drilled eight boreholes in the Makhonjwa Mountains and took samples from the Lomati water tunnel and two tunnels of Agnes Mine.
Heubeck said during the lecture that the cores and the samples could all be correlated, creating a stratigraphic framework from which scientists could trace the change of the various environments over a horizontal distance of about 20km as well as through several million years of time. “Nowhere else in the world is this possible,” said Heubeck.
He said that for more than half of its history, Earth was a bacteria planet.
To study the surface conditions of early Earth is to also study whether life had a tough time colonising the planet, and what the environment in which life was ultimately formed was like.
During the lecture, he showed photographs of three core samples extracted during the drilling projects to the audience, all of which showed signs of organic material. “Under what circumstances did they form? We know very little about this,” said Heubeck.
He said as one takes away the surface sedimentary layers of the Earth, one by one, the foundation of this continent begins to appear. These layers consist largely of plutonic and metamorphic rock, but also some greenstone belts.
Greenstone belts are the basement rocks for the Kaapvaal Craton. Some greenstone belts can also be found in the Johannesburg area and close to the Kalahari, but the best are found here in Mpumalanga and Limpopo, with the Barberton belt being the largest of them all.
The samples are currently still being processed. Some are being ground into a powder to be analysed in X-ray machines for chemical analysis using various methods.
On the morning after the lecture, a new room of the Barberton Regional Museum, dedicated to teaching the history of Earth, was handed over to the regional and local community by the international BASE Research Drilling Project.
The room is divided in two sections: information and interpretation. A series of large cut and polished rocks from the Makhonjwa Mountains is on display. A series of colourful posters on the walls and backlit banners explain what information is hidden in the rocks.
The room was originally an idea of Beukes’s. Astrid Christianson of Barberton Tourism organised the event, and Janie Grobler, head of the Barberton Museum, accepted the new room.
As one removes the surface sedimentary layers, the foundation of the continent begins to appear