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MADE-IN-EARTH
Researchers get beneath the surface of the earth
Analysis of rock microstructures can lead to important insights into key processes in the lithosphere, the outer part of the earth’s crust. The Made-In-Earth project aims to develop new quantification approaches, helping build a deeper understanding of phase transitions in the lithosphere, as Professor Lucie Tajčmanová explains
The analysis of rock samples and the chemical composition of microstructures found on the earth’s surface can help scientists build a deeper understanding of processes in the earth’s interior. By analysing rock samples, researchers can identify certain minerals and investigate the way they are arranged, from which new insights can be drawn. “These minerals, their composition and the way they are arranged can indicate the peak pressure and temperature conditions under which the rock microstructure developed,” explains Professor Lucie Tajcmanová, the Principal Investigator of the Made-In-Earth project, an ERC-backed initiative based at ETH in Zurich. Researchers in the project are developing new quantification approaches to quantitatively understand the data from metamorphic rocks. “We focus on so-called metamorphic rocks, rocks that have somehow metamorphosed, or otherwise been modified, from their original state,” explains Professor Tajcmanová.
Rock metamorphosis
This process of rock metamorphosis has an enormous impact on the earth’s surface. It is known that mineral reactions and phase transformations in the lithosphere help form mountain ranges, lead to volcanic eruptions, and trigger earthquakes, underlining the wider importance of improving our understanding of geodynamic processes. “We are collaborating with people who are developing a new generation of geodynamic models, while we also work with researchers in other areas,” outlines Professor Tajcmanová. However, while fully aware of the project’s wider implications, Professor Tajcmanová says their research is largely fundamental in nature. “We are currently focusing more on developing theoretical methods and we analyse rock samples from all over the world. We have some samples from the Bohemian massif in the Czech Republic, as well as from the Alps, the Himalayas, India, Norway, and other regions,” she continues.
Kaoko Belt (NW Namibia)
The project is focussing in particular on rocks that belong to the lithosphere, the outer part of the earth’s crust. Previously researchers compared the pressures and temperatures under which a rock developed to localise the area in which it was formed, but Professor Tajcmanová and her colleagues question the effectiveness of this approach. “With this approach it is assumed that rocks are like fluids, which is not true, as in fact they behave like solid phases with different mechanical properties. We are trying to develop new quantification approaches, a new way of thinking about how to look at certain observations in rocks,” she says. Researchers are developing theoretical approaches, coupling chemical and mechanical processes; a key first step in this work is in building new thermodynamic formulations. “This work is partly theoretical. With this ERC funding, we can really get into the fundamental equations and question whether they are appropriate or not,” continues Professor Tajcmanová.
Researchers are looking at chemical distribution processes in rock microstructures, together with the squeezing effects of deformation, to build a more detailed picture of processes in the lithosphere. The rocks that researchers are analysing are very small, ranging from
the millimetre down to the nanometre scale. “We mostly focus on the grain scale processes, because there we believe we can achieve a greater level of control over the key processes,” says Professor Tajcmanová. Even though these samples are very small, researchers are still able to identify mineral and pressure variations. “For instance, if we find even a tiny amount of a mineral inside a rock – which corresponds to high pressures – while the rest of the rock doesn’t look like that, then that raises interesting questions,” explains Professor Tajcmanová. “In these types of cases we should be careful – because the inclusion of high pressure regions might be a result of local stress perturbations and local pressure variations.”
our understanding of the earth’s interior
Pressure variations
This introduces a different dimension in research. If it is assumed that the pressure throughout a rock is homogenous, then it’s relatively easy to correlate it to a specific depth and localise it, but if it is found that pressure varies throughout a rock, then that raises questions about the reliability of the conventional approach. The project aims to take account of pressure variations within quantified systems, which can then be validated by numerical models, informing the ongoing development of geodynamic models. “Our data serves as the input data for geodynamic models, as we have direct observations of rock microstructures,” outlines Professor Tajcmanová. “If our input data is false, then of course it leads on to questions also about the quality of the overall geodynamic models and our understanding of the earth’s interior or the processes in the lithosphere.”
A greater level of control over key processes and more detail about the variables which affect rock structures could have a significant impact in these terms. Alongside the project’s collaborations with researchers developing new geodynamic models, Professor Tajcmanová and her colleagues are also working with scientists looking at certain environmental problems. “These chemical and mechanical processes don’t occur only in the deep crust, they can also occur on the surface. We believe that our data can help to support CO2 sequestration, and also nuclear waste disposal problems. Our numerical models, with this coupling of the diffusion and deformation, can also help us to better understand the processes
in those applications,” she says. The project’s research could also hold implications for the oil industry, particularly in terms of two-phase (solidliquid) flow. “We could also initiate some collaboration in that direction,” says Professor Tajcmanová.
There are plans to both pursue potential collaborations and continue fundamental research into the earth’s lithosphere over the remainder of the project’s funding term. This is a complex area of research, and Professor Tajcmanová says it’s important to be rigorous and thorough. “We are really going into the fundamental derivations, and we want to be sure that we have done everything carefully. So, we will continue improving these coupled derivations, coupled quantifications, and we will look towards collaboration with researchers doing more of these direct observations, so that we can apply the tools which we are developing,” she outlines.
Full Project Title
Interplay between metamorphism and deformation in the Earth’s lithosphere“ (2013-2018) (MADE-IN-EARTH)
Project Objectives
The development of the new quantification approach opens new horizons in understanding the phase transformations in the Earth’s lithosphere. Furthermore, the new data generated serve as a food for the next generation of geodynamic models as well as for societal aspects. In fact, explicit formulation of mass transport for natural, complex chemical system on a small scale will provide insights relevant to problems in material science such as rechargeable batteries as well as to radioactive waste disposal and CO2 storage programs.
Project Funding
Funded by the European Research Council.
Project Partners
• Please see website for full partner information.
Contact Details
Professor Lucie Tajcmanová ETH Zürich Department of Earth Sciences Inst. für Geochemie und Petrologie Sonneggstrasse 5 8092 Zürich Switzerland T: +41 44 632 29 77 E: lucie.tajcmanova@erdw.ethz.ch W: www.petromodelling.ethz.ch
Professor Lucie Tajčmanová
Professor Lucie Tajčmanová has been an Assistant Professor of Metamorphic Petrology since September 2013. She was born in the Czech Republic in 1978. She obtained a PhD at the Charles University, Prague, Czech Republic, in 2007. Afterwards she worked as a postdoctoral fellow at the University of Padova, Italy, until 2009. Before joining ETH Zurich as a Marie Curie Research Associate in 2011, she spent two years as a Humboldt postdoctoral fellow at the Freie Universität, Berlin, Germany.
