Scientists at Curtin University have developed a new technique to explore the deep history of Australia’s landscapes. This approach can help researchers understand how the environment responds to geological activity and climate change, while also potentially providing clues about where valuable mineral deposits are located.
This international research team was led by the Curtin Mineral Systems Timescale Group at the Faculty of Earth and Planetary Sciences, in collaboration with collaborators from the Universities of Göttingen and Cologne. Scientists examined microscopic zircon crystals collected from ancient beach sand.
Zircon is the most durable mineral found on Earth. Because zircon particles can withstand weathering, erosion, and long journeys through rivers and coastlines, they can survive for millions of years while preserving information about their geological history.
Inside these zircon particles is a rare gas known as krypton. This gas is formed when minerals near the Earth’s surface are hit by cosmic rays (high-energy, electrically charged subatomic particles from space).
By measuring the krypton trapped within the crystals, the researchers were able to estimate how long the zircon particles remain near the surface before eventually becoming buried. This measurement acts like a “cosmic clock,” allowing scientists to determine how quickly or slowly ancient landforms eroded and moved over very long periods of time.
A new way to study ancient landscapes
Dr Maximilian Dorner, lead author and Curtin Adjunct Research Fellow, who is also affiliated with the University of Göttingen, said the technique allows scientists to study landscapes much older than what they were previously able to analyze. The discovery could help researchers better understand how the Earth’s surface will respond to future climate change and tectonic activity.
“Our Earth’s history shows that climate and tectonic forces can control landscape behavior over very long time scales,” Dr. Drerner said.
“This study helps us understand what happens when sea levels change and how deep Earth movements influence the evolution of landforms.”
The study found that erosion slows significantly when the landscape remains tectonically stable and sea levels remain high. Under these conditions, sediments remain near the surface and can be repeatedly reworked over millions of years.
Why these findings matter for the future
Professor Chris Kirkland, co-author and leader of the Mineral Systems Timescale Group, said the results not only reveal how the Earth’s surface has evolved over billions of years, but could also be useful for future planning and land management.
“Modifying natural systems can be expected to change how sediment is stored along river basins, coastlines and continental shelves,” Professor Kirkland said.
“Our results show that these processes can fundamentally reshape not only coastlines but also landscapes over time.”
Connections between climate, sediments and mineral resources
Co-author Associate Professor Milo Barham, also a member of the Mineral Systems Timescale Group, said the study had important implications for understanding Australia’s mineral resources.
“Climate not only influences ecosystems and weather patterns, but also controls where mineral resources end up and how they become available,” Associate Professor Barham says.
“Long-term storage of sediments gradually concentrates the more durable minerals, while the less stable materials break down, which explains why Australia has some of the most important deposits of mineral sands in the world.
“Understanding these connections is important as demand for these minerals continues to increase, as it provides a long-term perspective that can improve models used to predict future environmental and resource outcomes resulting from changes in these sediment systems.”
The study, titled “Evolution of an ancient landscape traced through cosmogenic krypton in detrital zircon,” PNAS.
