Although we may not always notice it, the surface of our planet is constantly shifting below our feet.
To demonstrate this, scientists from the University of Sydney in Australia have modelled how the landscape of Earth has changed over the past 100 million years.
It takes into account how the climate has impacted the movement of sediment by rivers and seas, as well as the movement of the tectonic plates.
The researchers hope their model will enable theories on the future impacts of climate change on the Earth’s surface to be accurately tested.
‘To predict the future, we must understand the past,’ said lead author Dr Tristan Salles.
A picture of Earth after 50 million years of cumulative erosion and sedimentation, generated by the model. It shows erosion over mountain ranges and other high points, as well as major sediment accumulations along continental shelves and basins
‘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.’
The landscape of the planet today is the result of millions of years’ worth of climate change and tectonic plate movement.
These plates are composed of the Earth’s crust and upper portion of the mantle, its rocky second layer, and float on top of a hot, viscous belt of rock called the asthenosphere.
The asthenosphere causes them to collide and brush against each other, altering the landscape with the formation of mountains, volcanoes and earthquakes.
The climate, on the other hand, can impact the weathering of sediment, which causes it to break down and flow into bodies of water.
It can also cause rivers to form or flood, and alter their flow rates – processes which affect the movement of sediment.
For their model, published today in Science, researchers wanted to show how today’s geophysical landscapes evolved at the highest resolution yet.
They used geological records to simulate how land elevation changed over time, and then factored in ancient climate data from a separate computer model.
Their final model was calibrated and tested by comparing its predictions to real world natural examples of sediment formations and water flowing processes.
The landscape of the planet today is the result of millions of years’ worth of climate change and tectonic plate movement. These plates are composed of the Earth’s crust and upper portion of the mantle, its rocky second layer, and float on top of a hot, viscous belt of rock called the asthenosphere. The asthenosphere causes them to collide and brush against each other, altering the landscape with the formation of mountains, volcanoes and earthquakes
The climate, on the other hand, can impact the weathering of sediment, which causes it to break down and flow into bodies of water. It can also cause rivers to form or flood, and alter their flow rates – processes which affect the movement of sediment
A: A picture from the model showing the major rivers on Earth 50 million years ago, B: A picture of Earth after 50 million years of cumulative erosion and sedimentation, C: A portion of the Earth’s surface after 100 million years of landscape evolution
The resulting timelapse visualises the landscape at a high resolution, showing erosion up to 3 miles deep (5 km) and sediment deposits up to 3 miles high (5 km).
Each frame shows the progression of another million years on Earth.
Second author Dr Laurent Husson from Institut des Sciences de la Terre in 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.’
Human-induced climate change is known to be changing the chemical composition of the ocean, and processes going on inside of them.
The team hopes that the model will allow for better understanding of the impact this has on present day and future sedimentary processes.
Dr Salles said: ‘Our findings will provide a dynamic and detailed background for scientists in other fields to prepare and test hypotheses, such as in biochemical cycles or in biological evolution.’
The Earth is moving under our feet: Tectonic plates move through the mantle and produce Earthquakes as they scrape against each other
Tectonic plates are composed of Earth’s crust and the uppermost portion of the mantle.
Below is the asthenosphere: the warm, viscous conveyor belt of rock on which tectonic plates ride.
The Earth has fifteen tectonic plates (pictured) that together have moulded the shape of the landscape we see around us today
Earthquakes typically occur at the boundaries of tectonic plates, where one plate dips below another, thrusts another upward, or where plate edges scrape alongside each other.
Earthquakes rarely occur in the middle of plates, but they can happen when ancient faults or rifts far below the surface reactivate.
These areas are relatively weak compared to the surrounding plate, and can easily slip and cause an earthquake.
