Sark - Geography and Geology

Geography and Geology

Sark consists of two main parts, Greater Sark, located at about 49° 25' N x 2° 22' W, and Little Sark to the south. They are connected by a narrow isthmus called La Coupée which is 300 feet (91 m) long and has a drop of 330 feet (100 m) on each side. Protective railings were erected in 1900; before then, children would crawl across on their hands and knees to avoid being blown over the edge. There is a narrow concrete road covering the entirety of the isthmus, built in 1945 by German prisoners of war under the direction of the Royal Engineers. Due to isolation, the inhabitants of Little Sark had their own distinct form of Sercquiais, the native Norman dialect of the island.

The highest point on Sark is 374 feet (114 m) above sea-level. A windmill, dated 1571, is found there, the sails of which were removed during World War I. This high point is named Le Moulin, after the windmill. The location is also the highest point in the Bailiwick of Guernsey. Little Sark had a number of mines accessing a source of galena. At Port Gorey, the ruins of silver mines may be seen. Off the south end of Little Sark are the Venus Pool and the Adonis Pool, both natural swimming pools whose waters are refreshed at high tide.

The whole island is extensively penetrated at sea level by natural cave formations that provide unique habitats for many marine creatures, notably sea anemones, some of which are only safely accessible at low tide. Sea Ravens are very common in Sark.

Sark is made up mainly of the rocks amphibolite and granite gneisses, intruded by igneous magma sheets called quartz diorite. Recent (1990–2000) geological studies and rock age dating by geologists from Oxford Brookes University shows that the gneisses probably formed around 620-600 million years ago during the Late Precambrian-age Cadomian Orogeny. The quartz diorite sheets were intruded during this Cadomian deformation and metamorphic event. All the Sark rocks (and nearby Channel Islands of Guernsey & Alderney) formed during geological activity in continental crust above an ancient subduction zone. This geological setting would have been analogous to the modern day subduction zone of the Pacific ocean plate colliding and subducting beneath the North and South American continental plate.

Sark also exercises jurisdiction over the island of Brecqhou, only a few hundred feet west of Greater Sark. It is a private island, however has been recently opened to some visitors. Since 1993 Brecqhou has been owned by Sir David Barclay, one of the Barclay brothers, who are co-owners of The Daily Telegraph. They contest Sark's control over the island. However, the candidates endorsed by their various business interests on the Island, failed to win any seats in the elections held 2008 and 2010 .