The River Tweed at Berwick is an example of such a change from rocky cliffs to the north of the river and sand dunes to the south. Some of these dunes can, though, be as high as small cliffs. The dunes stretch from the Tweed to Holy Island.
To reach this cache turn off the A1 at the signpost for Cheswick and Goswick. Follow the signs to the Golf Club. Parking is permitted at the Golf Club and walkers are invited to use all the facilities there.
From there it is a short walk through the dunes and along the sandy beach. Depending on the tide you may well have to paddle or wade through a stream to reach the island.
Coastal sand dunes develop where there is an adequate supply of sand (sediment within the size range 0.2 to 2.0 mm) in the intertidal zone and where onshore winds are prevalent. The critical factor is the presence of a sufficiently large beach plain whose surface dries out between high tides. The dry sand is then blown landwards and deposited above high water mark, where it is trapped by specialised dune-building grasses which grow up through successive layers of deposited sand.
Sand dunes form in relatively exposed locations, and in a number of physiographic situations. The most common are bay dunes , where a limited sand supply is trapped between two headlands; spit dunes , which form as sandy promontories at the mouths of estuaries; and hindshore dunes , which occur in the most exposed locations where large quantities of sand are driven some distance inland, over a low-lying hinterland.
At the Goswick Island Dune please complete two tasks:
1. Take a photograph of yourself or your GPSr at or on the island and preferably with a background of Holy Island, Beachcomber Stables/Campsite of Berwick and upload this with your log entry.
2. Measure the distance around the base of the island and send the answer to me via e-mail. Please do not include it in your log.
After completing these tasks please go to N 55° 42.644, W 001° 55.024 where you will notice a number of much smaller sand dune islands being formed. The final task is to e-mail me the answer to the following question:
Apart from sand and grass what else can you see that helps form these island sand dunes?