The Loe | |
---|---|
Location | Cornwall |
Coordinates | 50°04′35″N 5°17′22″W / 50.07639°N 5.28944°WCoordinates: 50°04′35″N 5°17′22″W / 50.07639°N 5.28944°W |
Lake type | Eutrophic |
Primary inflows | River Cober |
Primary outflows |
Mine adit Infiltration |
Basin countries | United Kingdom |
Max. length | 2 km (1.2 mi) |
Max. width | 0.8 km (0.50 mi) |
Surface area | 50 ha (120 acres) |
Max. depth | 6 m (20 ft) |
Surface elevation | 0 m (0 ft) |
Islands | None |
Settlements | Helston |
The Loe (Cornish: An Logh), also known as Loe Pool, is the largest natural freshwater lake (50 hectares (120 acres)) in Cornwall, United Kingdom. The earliest recorded appearance of this simple name form was in 1337, when it was called "La Loo", but is mentioned as 'the lake' in 1302; Situated between Porthleven and Gunwalloe and downstream of Helston, it is separated from Mount's Bay by the shingle bank of Loe Bar. Both the Loe (including the southern arm known as Carminowe Creek) and Loe Bar are situated within the Penrose Estate, which is administered by the National Trust, and are designated as a Site of Special Scientific Interest by Natural England. It is within the Cornwall Area of Outstanding Natural Beauty and is considered a classic Geological Conservation Review Site. The South West Coast Path, which follows the coast of south-west England from Somerset to Dorset passes over Loe Bar.
The Loe was originally the estuary of the River Cober, a ria or drowned river valley now blocked by a sand and shingle bar with a fresh water lake behind. The valley can be traced several kilometres out to sea. The age of the bar is disputed, with estimates ranging from several thousand years to c. 700 years. With the melting of ice-sheets and glaciers after the last ice age, sea levels rose and reached their present levels about 6,000 years ago during what is known as the Flandrian Marine Trangression. The most likely origin is a barrier beach, (formed by wave action rather than by tides) that gradually moved onshore, as the sea level rose during the Holocene. The shingle coming from drowned terraces of the former river that flowed down the English Channel (the nearest onshore source is 120 miles away in East Devon). It is thought that Longshore Drift plays an important part in the maintenance of the Bar, with a strong current flowing to the south-east from Porthleven to Gunwalloe, depositing shingle along the Bar. The ebb flow is not a simple reverse flow and is not strong enough to remove all the deposits. The bar itself is a sediment sink as far as the overall beach budget is concerned. The deposits have been tentatively dated as Eocene and compared with Gunwalloe beach material, very little of the Loe Bar shingle is locally derived. The composition of the Bar deposits are: Chalk flint 86%, Quartz 9%, Grit 2.6%, Greensand chert 2% and Serpentine 0.5%.