THE latest technology has been employed to help unearth the secrets of the region's prehistoric rock art.

Five rocks in Teesdale, which are carved with stone age engravings, are being recorded using a technique called 3D laser scanning as part of the Northumberland and Durham rock art project.

The high precision technology was developed for use in engineering, but is now beginning to be used to record ancient monuments such as Stonehenge.

Only a handful of prehistoric carvings have been recorded using this method, and the Teesdale rocks on Cotherstone Moor are the largest number of carved panels scanned by one project.

Rock art project officer, Tertia Barnett, said: "The scanner sends a laser beam across the rock and records very small changes in the surface.

"Changes of less than 0.5mm can be captured and recorded as digital data on computer," she added. "This can be used to create extremely accurate 3D reconstructions of the rock surface and carvings."

One of the benefits of the technology is that the rock surface is not harmed in any way.

Ms Barnett called it a powerful tool for conserving rock art, allowing archaeologists to look in detail at the techniques used to make the prehistoric carvings, and subtle changes in the rock structure where it might have been eroded or damaged.

"This will help us assess how to protect the carvings from further decay," she said.

The computer generated reconstructions can be manipulated to create 3D animations for use in museums and schools as an educational tool.

"Nobody really knows what the carvings were for," said Ms Barnett. "There are lots of theories, and everyone has their favourite, from aliens to tribal rituals.

"They are very much a northern thing, which is partly why they have been overlooked in the past.

"The North does tend to take a back seat in archaeological circles and tends to get bypassed, so we have to do a lot of raising awareness nationally."

Much of the rock art, which features cup-shaped hollows, concentric rings and elaborately designed patterns, was created about 4,000 years ago, towards the end of the stone age.

There are ore than 1,000 examples in Durham and Northumberland and the project aims to compile a complete record which can be used to research and conserve it.

The project is funded by English Heritage and co-ordinated by Durham and Northumberland county councils.