The most detailed model of Earth’s surface ever

An advanced digital tool can help us understand the past and predict the evolution of the Earth’s surface.

The interaction of climate, tectonic activity, and the passage of time creates enormous forces that shape the appearance of our planet. Gentle erosion caused by rivers only adds to this, making what appears to be unchanging rock in fact a constantly evolving surface.

However, our understanding of this complex process has been limited at best.

Scientists have published new research that reveals a detailed and dynamic model of the Earth’s surface over the past 100 million years.

Working with scientists in France, University of Sydney geoscientists published this new model in the prestigious journal Sciences.

Animated landscape dynamics model over the past 100 million years showing landscape erosion and sediment deposition. Credit: Dr. Tristan Sales,[{” attribute=””>University of Sydney

For the first time, it provides a high-resolution understanding of how today’s geophysical landscapes were created and how millions of tonnes of sediment have flowed to the oceans.

Lead author Dr. Tristan Salles from the University of Sydney School of Geosciences, said: “To predict the future, we must understand the past. But our geological models have only provided a fragmented understanding of how our planet’s recent physical features formed.

“If you look for a continuous model of the interplay between river basins, global-scale erosion, and sediment deposition at high resolution for the past 100 million years, it just doesn’t exist. So, this is a big advance. It’s not only a tool to help us investigate the past but will help scientists understand and predict the future, as well.”

Lead author Dr. Tristan Salles from the School of Geosciences at the University of Sydney. Credit: Stefanie Zingsheim, The University of Sydney

Using a framework incorporating geodynamics, tectonic and climatic forces with surface processes, the scientific team has presented a new dynamic model of the past 100 million years at high resolution (down to 10 kilometers), broken into frames of a million years.

Second author Dr. Laurent Husson from Institut des Sciences de la Terre in Grenoble, France, said: “This unprecedented high-resolution model of Earth’s recent past will equip geoscientists with a more complete and dynamic understanding of the Earth’s surface.

“Critically, it captures the dynamics of sediment transfer from the land to oceans in a way we have not previously been able to.”

Animated world map of landscape evolution over the past 100 million years. Credit: Dr. Tristan Sales, University of Sydney

Dr. Sales said that understanding the flow of terrestrial sediments into marine environments is vital to understanding current ocean chemistry.

“Given that ocean chemistry is changing rapidly due to human-caused climate change, having a more complete picture could aid our understanding of marine environments,” he said.

The model will allow scientists to test different theories about how the Earth’s surface responds to climate change and tectonic forces.

Furthermore, the research provides an improved model for understanding how terrestrial sediment transport regulates the planet’s carbon cycle over millions of years.

“Our findings will provide a dynamic and detailed background for scientists in other areas to prepare and test hypotheses, such as biochemical cycles or in biological evolution.”

Reference: “One Hundred Million Years of Landscape Dynamics from Watershed to Global Scale” By Tristan Sallis, Laurent Huson, Patrice Rae, Claire Mallard, Sabine Zahirovic, Beatriz Hadler-Bogiani, Nicholas Coltice, Miles Arnold, March 2, 2023, Available Here. Sciences.
DOI: 10.1126/science.add2541

The study was funded by the Australian Government and the Australian Research Council.

The authors d. Sallis and D. Claire Mallard and Ph.D. Student Beatriz Hadler Boggiani is members of the EarthColab Group and Associate Professor Patrice Rey and Dr Sabin Zahirovic are part of the EarthByte Group. Both groups are in the School of Geosciences at the University of Sydney.

The research was carried out in collaboration with French geoscientists from CNRS, France, the University of Lyon, and ENS Paris.