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.

Landscape evolution over the past 100 million years. Credit: Dr. Tristan Sales, University of Sydney/AAAS

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

For the first time, it provides a high-resolution understanding of how today’s geophysical landscape was formed and how millions of tons of sediment flowed into the oceans.

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

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

“If you are looking for a continuous model of river basin interaction, erosion on a global scale, and sediment deposition at high resolution over the past 100 million years, it does not exist. So, this is a huge advance. It is not only a tool to help us investigate the past but it will also help scientists understanding and predicting the future.

Using a framework that combines geodynamics, tectonic and climatic forces with surface processes, the science team presented a new dynamical model of the past 100 million years at high resolution (up to 10 km), divided into million-year frames.

Lead author Dr Tristan Sales is from the University of Sydney’s School of Geosciences. Credit: Stephanie Zingsheim, University of Sydney

Second author Dr Laurent Huson of the Institute of Geosciences in Grenoble, France, said: “This unprecedented high-resolution model of Earth’s recent past will provide geoscientists with a more complete and dynamic understanding of the Earth’s surface.

“Crucially, it captures the dynamics of sediment transport from the land to the ocean in a way that we haven’t been able to do before.”

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.