FOLDS OF rock up to 70 million years old have given new clues as to how mountains and continents were formed.

A team of scientists from St Andrews and Oxford universities have studied ancient folds in the mountains of Oman, gaining insight into how the plates which make up Earth’s crust form and move.

Among the team, which found rock folds larger and more clearly exposed than ever before, was Dr Ian Alsop, of St Andrews.

He explained, “As rocks deep underground are pressed and heated they melt and begin to flow. This forms folds, like a rucked-up carpet.

“The folds in Oman show that the rocks moved many tens of kilometres while deep within the Earth.”

He added, “The folds that we have been analysing in Oman formed about 70 million years ago and are unique in that they display some of the largest, best exposed curved geometries anywhere on Earth.”

Oman has rugged mountains split by steep wadis—dry river beds— which expose many of these folds in great detail.

Such folds may be pushed as deep as 100 kilometres underground before returning to the planet’s surface in a dramatic mountain range.

Also visible now are portions of crust which were once under the ocean.

Dr Alsop, of the university’s school of geography and geosciences, is to return to Oman later in the year to continue the Royal Society-funded project.