International research team discovers new geological archive
The researchers have shown that several phases of Earth’s history have been preserved in the quartz of the fossilised wood. This opens up a new avenue for science to trace the evolution of landscapes and continents.
Dr Ronny Rößler, Director of the Chemnitz Museum of Natural History: “The roots of this study, now published in one of the world’s leading specialist journals, lie in Chemnitz: Dr Steffen Trümper began this work as a research trainee and PhD student at the Chemnitz Museum of Natural History. Together with our partners, we have driven this research forward over many years. We are therefore all the more delighted that the results are now attracting global attention – on scientific platforms such as ResearchGate as well as in numerous personal responses from the scientific community.”
For the study, the research team examined fossilised tree trunks from the Kyffhäuser region in northern Thuringia. The trunks, which are up to 20 metres long, originate from tropical dry forests that grew near the equator around 300 million years ago. Following floods, sediments covered the dead trees. Water containing silicic acid subsequently penetrated the wood. Over the course of millions of years, the silicic acid crystallised into quartz and replaced the original tissue. As a result, even the finest cellular structures were preserved.
Analyses show that five successive phases of fossilisation can be distinguished within the quartz. Each phase contains information about the temperature, pressure and chemical
conditions of their formation. Together, they document the history of the subsidence and subsequent uplift of the Saale Basin over a period of around 300 million years.
To decipher these time capsules, the research team combined various modern analytical methods. Among other things, they examined the properties of the quartz, tiny fluid inclusions and the chemical composition of the minerals, and determined their age. This made it possible to demonstrate that parts of the fossils once lay at depths of up to five and a half kilometres and were exposed to temperatures of up to 240 degrees Celsius.
Petrified wood is found in many rock formations around the world. These findings can help us better understand the geological development of entire regions and even the history of continents. The study also shows that the climatic and geological conditions under which the wood was originally embedded are the key factors in this process.
The study was led by the University of Münster. Other participating institutions included the Georg-August University of Göttingen, the Karlsruhe Institute of Technology, the Chemnitz Museum of Natural History and the TU Bergakademie Freiberg.