Skerry

Skerry outside Krøttøy in Harstad municipality, Norway

Skerries which are part of the Åland Islands, Finland

A skerry is a small rocky island, usually defined to be too small for habitation; it may simply be a rocky reef. A skerry can also be called a low sea stack.^[1]

The term skerry is derived from the Old Norse sker, which means a rock in the sea. The Old Norse term sker was brought into the English language via the Scots language word spelled skerrie or skerry. It is a cognate of the Scandinavian languages' words for skerry – Icelandic, Faroese: sker, Danish: skær, Swedish: skär, Norwegian: skjær / skjer, found also in German: Schäre, Finnish: kari, Estonian: skäär, Latvian: šēra, Lithuanian: Šcheras and Russian: шхеры (shkhery). In Scottish Gaelic, it appears as sgeir, e.g. Sula Sgeir, in Irish as sceir, in Welsh as sgeri, and in Manx as skeyr.

Formation

Skerries are most commonly formed at the outlet of fjords where submerged glacially formed valleys at right angles to the coast join with other cross valleys in a complex array. In some places near the seaward margins of fjorded areas, the ice-scoured channels are so numerous and varied in direction that the rocky coast is divided into thousands of island blocks, some large and mountainous while others are merely rocky points or rock reefs that menace navigation.

Examples

The island fringe of Norway is such a group of glacially formed skerries (called a skjærgård); many of the cross fjords are so arranged that they parallel the coast and provide a protected channel behind an almost unbroken succession of mountainous islands and skerries. By this channel one can travel through a protected passage almost the entire 1,600 km route from Stavanger to North Cape, Norway. The Blindleia is a skerry-protected waterway that starts near Kristiansand in southern Norway, and continues past Lillesand.

The “inside passage” provides a similar route from Seattle, Washington to Skagway, Alaska. Yet another such skerry-protected passage extends from the Straits of Magellan north for 800 km (500 mi) along the west coast of the South American continent.

The Swedish coast along Bohuslän is likewise guarded by skerries. Even the east coast of Sweden, in the Baltic Sea, has many big skärgårdar (archipelagos), notably Stockholm archipelago - Stockholms skärgård.

Islets and skerries in Loch Uisgebhagh, east of Benbecula, Scotland

The southwestern coast of Finland also has a great many skerries; so many, in fact, that they form an archipelago. This area is experiencing post-glacial rebound that connects the rising islands as they break sea level, revealing till deposits and eventually clay bottoms. The skerries exist as small rocky islands before uplift of adjacent terrain changes the classification of this landform into a tombolo.^[2]

In the Russian Federation, the best examples are the Minina Skerries, located in the Kara Sea, in the western shores of the Taymyr Peninsula, and the Sumsky Skerries (Sumskiye Shkhery) 64°24′N 35°30′E / 64.400°N 35.500°E, located in the White Sea.

The United Kingdom has a large number of skerries including Staple Island (an Outer Farne Island) in England, a small rocky outcrop near the Fowlsheugh in northeast Scotland and numerous reefs in the Hebrides such as Dubh Artach and Skerryvore.

The most southerly skerries are perhaps the Skrap Skerries off South Georgia.

See also

• Stack (geology)

References

1. Johnson, M.E., & Webb, G.E. (2007). Outer rocky shores of the mowanbini archipelago, devonian reef complex, canning basin, western Australia. The Journal of Geology, 115. Retrieved from http://web.ebscohost.com/ehost/pdf?vid=3&hid=2&sid=eebecdd1-4007-4fe9-a0df-9e1d32ced4eb%40sessionmgr11
2. Tolvanen, H, Numminen, S, & Kalliola, R. (2004). Spatial distribution and dynamics of special shore-forms (tombolos, flads and glo-lakes) in an uplifting archipelago of the baltic sea. Journal of Coastal Research, 20(1), Retrieved from http://web.ebscohost.com/ehost/pdf?vid=5&hid=106&sid=f961ee3f-cbb0-4145-98a6-0a704ba7f31b%40sessionmgr111