The stretching and extension of the Tibetan Plateau is partly caused by the northward movement of the Indian Plate beneath the Eurasian Plate, reports a study published online this week in Nature Geoscience. Previously the extension of the plateau was largely thought to be the result of it collapsing under its own weight.

Richard Styron and colleagues use a computer model to simulate the evolution of the Tibetan Plateau as the Indian and Eurasian tectonic plates collided. The model results confirm that the entire plateau has been collapsing under gravity and stretching out eastwards since roughly 16 million years ago.

However, the simulations also show that a second wave of extension began a few million years later. This later wave, occurring at a faster rate than the initial rifting, moved from south to north in tandem with the northward subduction of the Indian Plate. The researchers suggest that as the Indian Plate is progressively forced northwards, farther beneath the Eurasian Plate, the crust at the surface stretches over it.