An ancient ocean that disappeared millions of years ago may have played a crucial role in shaping the mountains of Central Asia, according to new research by geologists from the University of Adelaide. The study suggests that the rise and fall of mountain ranges in the region were influenced not only by local tectonic forces, but by plate movements linked to the distant Tethys Ocean during the age of dinosaurs.
The findings challenge long-held explanations that attribute Central Asia’s rugged landscape mainly to climate change or deep mantle processes. Instead, researchers argue that tectonic shifts triggered by the slow closure of the Tethys Ocean sent geological ripples across Eurasia, reshaping terrain thousands of kilometres away.
How a Distant Ocean Influenced Central Asia’s Landscape
To reach their conclusions, scientists combined hundreds of thermal history models developed over nearly 30 years of geological research in Central Asia. By analysing this vast collection as a single dataset, they were able to identify long-term patterns that individual studies had failed to detect.
According to Dr Sam Boone, a former postdoctoral researcher at the University of Adelaide, the region remained largely arid for much of the past 250 million years, limiting the role of climate in shaping its landscape. “We found that climate change and mantle processes had only a minor influence,” he said. “Instead, short-lived periods of mountain building in Central Asia closely match changes linked to the evolution of the Tethys Ocean.”
At its peak, the Tethys Ocean lay between major continental landmasses and played a central role in global plate movements. As it gradually closed during the Mesozoic and Cenozoic eras, tectonic stresses were transmitted far inland. Although the ocean itself has vanished leaving only remnants such as the Mediterranean Sea its geological imprint appears to be preserved in Central Asia’s mountains.
Mountain Building Long Before the Himalayas Emerged
While the dramatic collision between India and Eurasia later shaped much of the region’s present-day relief, researchers say Central Asia was already mountainous during the Cretaceous period, long before the Himalayas formed. Associate Professor Stijn Glorie explained that dinosaurs would have seen a landscape marked by parallel ridges, similar to today’s Basin and Range Province in the western United States.
The study suggests that tectonic extension linked to the rollback of subducting oceanic plates in the Tethys region reactivated ancient fault lines in Central Asia. These old suture zones were pushed upward into mountain ranges, despite being located thousands of kilometres from the main collision zones.
Using thermochronology-based thermal models, the team traced how rocks cooled as they were uplifted and eroded over time. By aligning these histories with plate tectonic models, precipitation data and mantle convection patterns, the researchers reconstructed a more complete picture of how distant tectonic forces shaped the region.
Published in *Nature Communications Earth and Environment*, the study also points to wider applications of this approach. The researchers say similar methods could help explain poorly understood geological histories elsewhere, including the breakup of Australia from Antarctica, where conventional models have failed to match observed thermal records.
Together, the findings highlight how vanished oceans can continue to influence Earth’s surface long after they disappear, leaving behind mountain ranges that carry the memory of ancient tectonic movements.