An ancient river bed that has lain unseen for 185,000 years has been uncovered by scientists mapping the parts of the English Channel in the run up to the 2012 Olympics.
The groundbreaking discovery was made during a two-year £300,000 project to map 500 square miles of seabed off the Jurassic coast in Dorset.
Using new and incredibly accurate mapping techniques, experts traced the river that may have once been used as a watering hole by woolly mammoths that roamed the area.
An amazing river course on the bottom of the English channel has been revealed (above). The prehistoric river bed is 8 miles from the present day shoreline (below)
The mysterious river bed cuts through bedrock at the bottom of the ocean and is eight miles long, ranges between 90 to 150 yards wide and up to 30ft deep. Scientists believe it would have flowed when Britain was still attached to the continent.
As ice melted and refroze, it was washed over and uncovered a second time, before finally being hidden at the bottom of the sea during the last Ice Age 12,000 years ago.
As well as the river bed, shipwrecks, rugged cliffs and massive gravel dunes have also been highlighted using the new techniques which can pinpoint objects to within six inches.
Scientists are aiming to construct a complete and definitive map ahead of the 2012 Olympics as thousands of boats are due to descend upon Dorset for the sailing events.
Smaller yachts have recently come a cropper on submerged rocks that maritime officials knew nothing about and they don’t want this happening in 2012.
The newly-found river bed poses no such danger as it lays 130ft underwater.
The project has been lead by the Dorset Wildlife Trust, which hopes the new information will be invaluable in its conservation work.
Dorset’s Jurassic Coast is famous for its fossils
Dr Simon Cripps, director of the Dorset Wildlife Trust, said: “On land you can just look out of the window and see what’s around, but we have no real idea what goes on under the sea.”
“This study will give us an understanding of what is actually physically down there – it’s very exciting.”
“It’s like putting a 3D jigsaw together in three layers and the results will be quite spectacular.”
Now the Maritime and Coastguard Agency is planning to re-chart nautical maps of the Channel. Some current charts are based on surveys carried out 75 years ago.
The maps have been created using a high resolution multi-beam sonar, which sends out 40 ‘pings’ per second to the seabed.
The sonar has 500 beams which give 20,000 readings per second, allowing scientists to gauge the depth of the ocean, with an accuracy of six inches.
Not only can it tell how deep the sea goes, but the variation of sounds created by the beams can identify the type of surface it is hitting.
The ‘pings’, which sound like the clicks made by dolphins to the human ear, differ depending on whether they hit sand, hard rock, or any matter in between.
The Dorset Integrated Seabed Study, or DORIS for short, is now one year in and moving on to a second phase of video and photography.
Experts will use the maps to identify patterns in the seabed before using cameras to take shots of underwater life.
The unique new underwater survey that has an accuracy of 15cm.
They will visit a range of depths to study the animal and plant life, taking still and moving images to create an elaborate picture of previously hidden habitats.
Richard Edmonds, science manager for the Jurassic Coast World Heritage Site, said: “The pictures the study has produced are hugely exciting, I was absolutely blown away when I first saw them.”
“We now know that all the fascinating structures we see on the Jurassic Coast, which are created by the hard and soft rocks eroding at different paces, happen exactly the same on the seabed.”
“When the river bed was uncovered, the land would have been used by woolly mammoths, raindeer and wolves as well as early humans.”
