FINGER-PT: Tracking our planet's history from tiny fragments of rock

The ground beneath our feet is made up of a wide variety of elements. Everything that fills this vast surface is influenced by what goes on deep inside the Earth when it comes to climate and biodiversity. The lithosphere, the outermost solid layer of the planet, is shaped every day by a variety of natural processes.

But has the planet always behaved this way? How did the Earth’s surface move when it first formed, nearly 4.6 billion years ago? When did this dynamic begin? And how did the first mountain chains appear?

These are the key questions that are driving the FINGER-PT project (Fingerprinting Subduction and Plate Tectonics Using Key Minerals).

Led by the University of Coimbra and with nearly €2.5 million in funding from the prestigious European Research Council, FINGER-PT explores the evolution of plate tectonics (PT) - the movement of large blocks of rock that lead to the formation of mountains, volcanic eruptions and earthquakes, to “try to understand when plate tectonics, with subduction zones similar to those seen today in the Pacific Ring of Fire,- an area of intense seismic and volcanic activity- first appeared in Earth’s geological record,” explains Inês Pereira, researcher at the Geosciences Centre (CGeo) of the Department of Earth Sciences, Faculty of Sciences and Technology, University of Coimbra (DCT/FCTUC), and coordinator of the project.

“Despite major efforts to understand it, we still don’t know exactly when this incredible geological process began,” says the UC researcher. "All we know is that when the Earth formed, around 4.57 billion years ago, plate tectonics didn't exist, although we now know it has been active for at least one billion years”. In an attempt to shed light on this lingering mystery, the FINGER-PT team is studying minerals — namely rutile, titanite and garnet — preserved in sedimentary rocks that were formed in ancient rivers or on beaches. “We’re using these minerals to trace the metamorphic conditions they were exposed to, so we can find out when plate tectonics began to resemble modern-day PT,” explains Inês Pereira.

“The analysis of these sediments relies on their chemical composition, which allows us to study these records of the past, since they all originated from rocks affected by plate tectonics,” Pereira notes.

The fascinating idea that the distant past can be uncovered through tiny grains of mineral is what drives this young researcher, who is driven by a desire to explore this concept further. However, Inês Pereira is well aware of the challenges posed by such an experimental approach. “Taking these tiny grains and determining the pressure, temperature and age of the rock they came from based solely on the information they hold is a huge challenge.”

The Department of Earth Sciences of the University of Coimbra has established two new laboratories to support this innovative research as part of the FINGER-PT project. The e-Microscale Lab allows researchers to study the types and textures of minerals using scanning electron microscopy and Raman spectroscopy. Meanwhile, the i-Geochronos Lab focuses on isotopic and trace element analysis, enabling researchers to determine the age of minerals.

For Inês Pereira, securing such a highly competitive research grant means more than just funding the project itself. It also represents an opportunity for her to return to Portugal after completing a postdoctoral fellowship in France. Despite the chronic underfunding of science in Portugal, particularly in fundamental research, she says she had a "strong desire to come back to the country to work and teach others".

Colleagues played a key role in bringing this project to fruition, starting with the Strategic Areas Office at the University of Coimbra. When she returned to Portugal in the summer of 2022, Inês Pereira met an amazing team who encouraged her to move forward with the project despite her doubts about applying for funding and transitioning from postdoc to principal investigator.

The research team behind FINGER-PT, which brings together expertise in areas such as geology and educational sciences, is also essential to the project’s success and to ensuring the future transfer of knowledge. These contributions include master’s dissertations, doctoral theses and scientific publications, as well as teaching resources. “We’re making a strong effort to include a dimension that I have always wanted to bring to this project, which is to take a fundamental scientific investigation and translate its outcomes into educational applications, especially by developing teaching resources for secondary and higher education students,” she explains.

Beyond national collaborations, FINGER-PT is building strong international partnerships. Researchers in countries such as France, Canada and Italy are set to play a pivotal role in supporting sample collection and experimental tasks, including the production of synthetic rocks. Spanning continents and disciplines, FINGER-PT is now searching the world for new clues to help us better understand the deep past of our planet.

_{Content Production and Editing: Catarina Ribeiro, DCM; Inês Coelho, DCM
Image and Video Editing: Ana Bartolomeu, DCM; Maria Cano, DCM
Translation [PT - EN]: Diana Taborda, DCM}