Measuring the Earth's surface in the laboratory

Joint information from the Ministry of Science, Research and Culture of Brandenburg and the GFZ German Research Centre for Geosciences.

On 11 June, the new "laboratory for the geochemistry of the Earth's surface" (HELGES) of the GFZ German Research Centre for Geosciences was opened in the presence of Prof. Dr. Ing. Dr. Sabine Kunst, Minister of Science, Research and Culture of Brandenburg. In the laboratory, the geology and chemical composition of the Earth's surface will be investigated using the latest ultra-precise physical methods such as mass spectrometry and laser technology. The funding of € 4.9 million for this geochemical high-tech laboratory was made possible with funds from the Helmholtz Association. 10% of this is supplied by the state of Brandenburg, the remaining 90% by the federal government.

Research minister Kunst in her speech: "With the HELGES laboratory, a further step is taken towards the international visibility of the German Research Centre for Geosciences. In addition, it is a measure to remedy the shortage of space here on Telegraph Hill. The GFZ is literally bursting at the seams, which is a result of your excellent work, to which I cordially congratulate you on such a pleasant day."

How quickly is ground is removed by erosion, how old is a glacial deposit, how many materials are carried into the oceans by the major rivers? The age of the earth's surface is measured in thousands of years, its change is often so slow that it can hardly be measured directly. Geoscientists therefore use the permanent cosmic radiation that our planet is exposed to. This radiation produces extremely rare isotopes of certain elements, so-called "cosmogenic nuclides", whose continuous generation constitutes a natural clock. Professor Friedhelm von Blanckenburg (GFZ), the head of the laboratory, explains the accuracy of the measurement methods: "The ultrapure HELGES laboratory allows the detection of single atoms in a large bag of river sand from the Amazon". 

But even if we then know the quantities of elements (e.g. magnesium, iron, silicon) that are removed from rocks on the Earth’s surface and are subsequently available to the formation of soils and as nutrients for plants, our understanding of the natural chemical and biological processes is very limited. Geoscientists detect these processes because the amounts of the isotopes in these elements shift very slightly. “This shift is like a ‘chemical fingerprint’ of information about the underlying processes, from today until far into the Earth’s past”, von Blanckenburg says: "Making these tiny isotope shifts visible represents an enormous technical challenge. An analogy: Measuring the circumference of a rough football field with an accuracy of half a matchstick length." This precision is reached by the GFZ scientists with an advanced ICP mass spectrometer. They perform these measurements on samples from the million square kilometers covering the Amazon River, but also on microscopic mineral grains that are analyzed at the GFZ with a newly developed, innovative femtosecond laser system.

"With these new techniques, the German Research Centre for Geosciences has world-class equipment for measuring the processes of the earth's surface at its disposal," says Professor Reinhard Huettl, Chairman of the Board of the GFZ. "We especially want to understand how our livelihood, the soils and rivers of planet Earth, arise and change. The constant natural change is only visible through our highly sensitive methods. Only with such a basic understanding can we estimate how large man-made changes, such as climate change or land use, are and how to respond to them."