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Unusual pancake shaped ice formations that are more typically seen in Arctic and Antarctic sea ice have been found floating on a river in Scotland.

The dinner plate-sized ice 'pancakes' have formed on a quiet stretch of the River Dee in Aberdeenshire.

The strange formations were photographed at the Lummels Pool, Birse, near Aboyne, by Jamie Urquhart, a biologist for the River Dee Trust.

The dinner plate-sized ice pancakes were found in an area known as the Lummels Pool on the River Dee. Normally pancake form on ocean water or lakes around the Arctic circle where the movement of water keeps the ice from forming a flat sheet

The pancakes are thought to have formed from foam created by faster flowing water further upstream, accumulating in a corner of a pool.

Freezing temperatures last week caused the foam to freeze, and the current bashed them into a circular shape.

Normally pancakes form on ocean water or lakes around the Arctic circle where the movement of water keeps the ice from forming a flat sheet.

However, they do ooccasionally occur on rivers when temperatures drop low enough.

Officials at the Dee River Trust said it is the first time they have seen pancake ice form on the river.

Mr Urquhart said: 'I've actually seen them before at the River Brora in Sutherland a couple of winters ago, but they were much smaller - more the size of a saucer.

'It's the first time we've seen them at the Dee. They are quite a rare occurrence, the conditions have to be right for them to occur.

'I've spoken to a number of people across the catchment, the people on the river, such as the ghillies and anglers, who have never seen them here before.

'I don't know if it's because we've had more extreme winters over the last couple of years, and then that hard frost.'

In the Arctic and Antarctic, pancake ice usually forms in rough seas, which prevent tiny crystals of ice, known as frazil crystals, that rise to the surface from bonding together.

Instead, the needle-like crystals accumulate into slushy circular disks. The edges around the perimetre of each disk becomes raised as the pancakes bump into each other from the movement of the ocean waves.

The ice pancakes were around an inch thick and the size of a dinner plate on the River Dee in Aberdeenshire. In the Arctic and Antarctic, pancake ice usually forms in rough seas, which prevent tiny crystals of ice, known as frazil crystals, that rise to the surface from bonding together

The pancakes accumulated downstream of faster water that is thought to have created foam, that then froze. It is thought that particularly hard frosts last week helped to cause the disks to form, but experts are baffled as to why they have not been seen on the river before in previous years

The strange formations were photographed at the Lummels Pool, Birse, near Aboyne (marked), by Jamie Urquhart, a biologist for the River Dee Trust

In the Arctic, these can bond together to form ridges that pile on top of each other and reach up to 60ft (18 metres) thick in places.

It is thought that particularly hard frosts last week helped to cause the disks to form but they are baffled as to why they have not been seen on the river before in previous years.

Joanna Dick, a spokesman for the River Dee Trust, said: 'We think foam floating about on the water started to freeze, probably at night.

'Bits of frozen foam got pushed around in the eddy, and in the ensuing collisions, became roughly circular.

'Perhaps each disc grew when smaller pieces of unfrozen foam struck the disc, adhered and then froze in place."

Joanna Dick, a spokesman for the River Dee Trust, said: 'We think foam floating about on the water started to freeze, probably at night. Bits of frozen foam got pushed around in the eddy, and in the ensuing collisions, became roughly circular'

Pancake ice in Antarctica's Ross Sea can form plates that are between a foot (12-inches) and nine feet (108 inches) in diameter