Pamir Mountains in Tajikistan
New research has reanalyzed hundreds of models and found that the Tethys Ocean played an important role in shaping Central Asia’s rugged topography.
The imposing mountains of Central Asia may owe their origin not only to local tectonic forces, but also to influence of an ancient ocean thousands of kilometers away, according to new research from University of Adelaide geologists in Nature Communications Earth and Environment.
The study suggests that the Tethys Oceanlong gone, played a key role in shaping the landscape of Central Asia during the Cretaceous period, when dinosaurs roamed the Earth. The researchers argue that distant plate movements linked to the Tethys were an important factor in short-lived but significant mountain-building events across the region.
To reach this conclusion, the team took an unusual approach. Instead of collecting new field data, they compiled and reanalyzed hundreds of models of thermal history published over nearly 30 years of geological investigation in Central Asia. By treating these individual studies as a single, broad dataset, scientists were able to detect large-scale patterns that are difficult to identify in isolated investigations, explains .
The rugged topography of Central Asia is generally explained as the product of complex interactions between tectonics, climate change and processes deep in the Earth’s mantle over the past 250 million years. However, the new analysis challenges this view.
“We found that climate change and mantle processes had little influence on the landscape of Central Asia, which has persisted in an arid climate for much of the last 250 million years,” said lead author, Sam Boonewho conducted the research as a postdoctoral fellow at the University of Adelaide. “Instead, the dynamics of the distant Tethys Ocean can be directly correlated with brief periods of mountain formation in Central Asia.”
During the Mesozoic and early Cenozoic eras, the Tethys Ocean was located between large continental blocks and strongly influenced the movements of global tectonic plates. As the ocean gradually closed, the tectonic stresses were transmitted across Eurasia. Although Tethys itself has disappeared, its geological traces appear to be preserved in the mountains of Central Asia.
Although today’s topography is largely the result of the collision between India and Eurasia that formed the Himalayas, Central Asia it was already mountainous during the Cretaceous. Dinosaurs will have seen a landscape similar to the present-day Basin and Range Province of the western United States, shaped by the extension and reactivation of ancient fault zones far from the Himalayan collision front.
The researchers used thermal history models based on thermochronology, which track how rocks cool as they rise toward the surface during uplift and erosion. By comparing these records with models of plate tectonics, climate and mantle convection, the team reconstructed previously hidden phases of mountain formation.
Researchers are now using the same approach to investigate other unsolved geological puzzles, including the separation of Australia from Antarctica around 80 million years ago.
