How were the Himalayan mountains shaped? Surprisingly, long before the collision between what is now India and Central Asia.
To understand the mechanisms, geologists from the University of Adelaide compiled hundreds of thermal models conducted over three decades. Their analyses reveal that the ancient Tethys Ocean, as it gradually closed, sent out tectonic waves. These forces influenced the landscape even before the two continental masses met.
By treating these models as a coherent set, the researchers were able to identify long-term geological trends. This work indicates that the persistent arid climate and the activity of the Earth's mantle had a relatively minor impact on the landscape.
Illustration image Pixabay
To trace the history of the rocks, the team used thermochronology methods. These techniques show how materials cool as they rise to the surface during a mountain uplift episode. Subsequently, cross-referencing this data with models of plate tectonics and ancient precipitation allowed a link to be established between the evolution of the Tethys Ocean and the successive phases of mountain building.
This approach could be applied to other regions where the formation of landscapes remains poorly understood. Another case is the separation of Australia and Antarctica, about 80 million years ago, which does not leave a clear mark.
In the Cretaceous period, when dinosaurs populated the Earth, Central Asia already had a mountainous landscape, comparable to that of the Basin-and-Range Province in the United States. The modification of the Tethys Ocean, caused by the retreat of subducting plates, reactivated ancient suture zones. This phenomenon created parallel ridges very far from the future site of the Himalayan collision.
Published in
Nature Communications Earth and Environment, this study helps to better interpret the history of continents and to consider certain future geological developments.