Prof Dirk Frei handling zircon samples.
(Image: Engela Duvenhage)
• Engela Duvenage
Media: Faculty of Science
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Wilma den Hartigh
Stellenbosch University is the first such institution in Africa to invest in state-of-the-art technology to determine the age of rocks, symbolising a major advancement for geosciences in the country.
The new Thermo Element 2 HR-SF-ICP-MS unit has only been operational for about three months, but it is already adding great value to the work of South African geologists.
“It is fascinating technology and it has numerous strategic, commercial and scientific applications,” says Prof Dirk Frei, head of the ICP-MS Facility at Stellenbosch University (SU).
Frei says it is the only unit of its kind in use for highly precise geochronology in Africa. Elsewhere in the world, there are only a handful of similar units that are used to perform geochronological research in the academic sphere.
Geochronology is a branch of geology that is used to determine the age of rocks, fossils and sediments.
It is used to establish the absolute ages of the crystallisation of magmatic rocks such as granites, the formation of mountain belts such as the Alps, and the formation of mineral deposits such as diamond-bearing kimberlites and gold-bearing alluvial placer deposits.
Benefits for SA geologists
“One of the main incentives of the facility is to serve the South African geosciences community with reliable age dating technology for the rocks they are studying, instead of using rock facilities in other countries at a major cost,” Frei says.
The cost of using rock dating facilities in a country such as Australia is at least three times higher than in South Africa.
Having the technology in South Africa is a major benefit for local geologists working in industry and the academic field, as they no longer have to travel abroad to do geochronological research.
“Given the outstanding geology of South Africa and the mineral richness of the country, the database of age information is very small,” he says. The reason for this is that many scientists don’t get access to rock-dating facilities, but the new technology will change this.
South African geologists have always used various methods to determine the age of rocks, fossils and sediments, but the processes available to them were often very slow and costly. In the past geologists had to rely on chemical analysis, which is also a highly involved and expensive process.
Geologists can now conduct in-depth research and answer questions about tectonic evolution and the age of the African continent, without leaving the country.
Sample analysis using the new equipment is also faster and more cost-effective, without compromising on accuracy.
Frei says the technology handles samples with “incredible sensitivity” to provide highly accurate measurements. Up to 600 age determinations can be made per day, each taking less than a minute.
“We invested R4-million (US$526 000) in the new facility, whereas the cost for a similar quality analysis would be more, but with a lower sample throughput,” he says.
The new equipment extends the ability to geochronologically date minerals such as zircon, apatite and monazite.
Zircon is of geological importance as it is one of the oldest minerals found on earth, and is used extensively to produce anything from bathroom accessories to containers that can hold radioactive materials.
Frei says the technology can help geologists determine the age of gold reefs more accurately. “If we can understand how gold reefs have been formed, we can better predict where to find them and target their exploration more accurately,” he says.
In the future, the new facility will also make it easier for scientists to study commodities such as platinum, lithium and uranium. “The commercial need for these commodities will become more important in the future. This is why the centre is also strategically important for the country,” he says.
The facility has also generated great interest among the international scientific community. Frei says about 50% of their work at the centre is from overseas, particularly Europe.
“The new equipment will help us unravel geological processes, and will definitely ensure that a host of highly cited articles are published based on the data,” he says.