Northern Isles
The Northern Isles are an archipelago located off the north coast of the Scottish mainland. The climate is cool and temperate and highly influenced by the surrounding seas. There are two main island groups: Shetland and Orkney. There are a total of 36 inhabited islands, with the fertile agricultural islands of Orkney contrasting with the more rugged Shetland islands to the north, where the economy is more dependent on fishing and the oil wealth of the surrounding seas. Both archipelagos have a developing renewable energy industry. They share a common Pictish and Norse history, and were part of the Kingdom of Norway before being absorbed into the Kingdom of Scotland in the 15th century. The islands played a significant naval role during the world wars of the 20th century.
Tourism is important to both archipelagos, with their distinctive prehistoric ruins playing a key part in their attraction, and there are regular ferry and air connections with mainland Scotland. The Scandinavian influence remains strong, especially in local folklore and both island chains have strong, though distinct local cultures. The names of the islands are dominated by the Norse heritage, although some may retain pre-Celtic elements.
Geography
The phrase "Northern Isles" generally refers to the main islands of the Orkney and Shetland archipelagos. The Island of Stroma, which lies between mainland Scotland and Orkney, is part of Caithness, so for local government purposes it falls under the jurisdiction of the Highland council area, rather than that of Orkney. It is nevertheless clearly one of the "northern isles" of Scotland. Fair Isle and Foula are outliers of Shetland, but would normally be considered part of Shetland, and thus of the Northern Isles. Similarly, Sule Skerry and Sule Stack, although distant from the main group, are part of Orkney, and therefore technically amongst the Northern Isles. However, the other small islands that lie off the north coast of Scotland are in Highland, and are thus not usually considered to be part of the Northern Isles.Orkney has 20 inhabited islands and Shetland has 16.
Orkney is situated north of the coast of mainland Scotland, separated from it by the waters of the Pentland Firth. The largest island of Orkney, known as the "Mainland" has an area of, making it the sixth largest Scottish island. Its total population in 2001 was 19,245, and its largest town is Kirkwall. Shetland is around north of mainland Scotland. It covers an area of and its coastline is long. Lerwick, the capital and largest settlement, has a population of around 7,500. About half of the archipelago's total population of 22,000 people live within of the town.
Geology
The superficial rock of Orkney is almost entirely Old Red Sandstone, mostly of Middle Devonian age. As in the neighbouring mainland county of Caithness, this sandstone rests upon the metamorphic rocks of the Moine series. This can be seen on the Orkney Mainland, where a narrow strip of the older rock is exposed between Stromness and Inganess, and also on the small island of Graemsay.Middle Devonian basaltic volcanic rocks are found on western Hoy, on Deerness in eastern Mainland and on Shapinsay. A correlation between the Hoy volcanics and the other two exposures has been proposed, but because of differences in their chemical makeup, this remains uncertain. Lamprophyre dykes of Late Permian age are found throughout Orkney. Glacial striation and the presence of chalk and flint erratics that originated from the bed of the North Sea demonstrate the influence of ice action on the geomorphology of the islands. Boulder clay is also abundant, and moraines cover substantial areas.
The geology of Shetland is quite different from that of Orkney. It is extremely complex, with numerous faults and fold axes. The Shetland Islands are the northern outpost of the Caledonian orogeny, and there are outcrops of Lewisian, Dalriadan and Moine metamorphic rocks whose histories are similar to those of their counterparts on the Scottish mainland. There are also small Old Red Sandstone deposits and granite intrusions. Shetland's most distinctive geological feature is the ultrabasic ophiolite, peridotite and gabbro on Unst and Fetlar, which are remnants of the Iapetus Ocean floor. There are oil-bearing sediments in the surrounding seas, on which much of Shetland's economy depends.
Geological evidence shows that, sometime around 6100 BC, a tsunami caused by the Storegga Slides hit the Northern Isles, and may have created a wave of up to high in the voes of Shetland, where modern populations are largest.
Climate
The Northern Isles have a cool, temperate climate that is remarkably mild and steady for such a northerly latitude, due to the influence of the surrounding seas and the Gulf Stream. In Shetland, average peak temperatures are in February and in August. Temperatures over are rare. The frost-free period may be as short as three months.The average annual rainfall is in Orkney and in Shetland. Winds are a key feature of the climate. In summer, there are almost constant breezes. In winter, there are frequent strong winds: Orkney has an average of 52 hours of gales annually. The Burradale wind farm in Shetland, which operates with five Vestas V47 660 kW turbines, achieved a world record of 57.9% capacity over the course of 2005 due to the persistent strong winds.
Snowfall is usually confined to the period of November to February and seldom lies on the ground for more than a day. Less rain falls between April and August than at other times of the year, but no month has an average rainfall of less than. In Shetland there are 1082 hours of bright sunshine per year, on average, and overcast days are common.
To tourists, one of the fascinations of the islands is their "nightless" summers. On the longest day in Shetland there are over 19 hours of daylight, and it never gets completely dark. The long twilight is known in the Northern Isles as the "simmer dim". Winter nights are correspondingly long, with less than six hours of daylight at midwinter. At this time of year the aurora borealis can occasionally be seen on the northern horizon during moderate auroral activity.
Prehistory
There are numerous important prehistoric remains in Orkney, especially from the Neolithic period. Four of these remains comprise the Heart of Neolithic Orkney UNESCO World Heritage Site. They are: Skara Brae; Maes Howe; the Stones of Stenness; and the Ring of Brodgar. The Knap of Howar Neolithic farmstead on the island of Papa Westray is probably the oldest preserved house in northern Europe. This structure was inhabited for 900 years, beginning around 3700 BC, but it had evidently been built on the site of an even older settlement. The Shetland Islands are also extremely rich in physical remains from prehistoric eras: They contain a total of over 5,000 archaeological sites. On the island of Fetlar, there is a dividing wall, dating from the Neolithic period, that at one time extended for across the island. It is known as Funzie Girt. But it is the Iron Age that has provided the most outstanding archaeology in Shetland. Numerous brochs were erected during that period. The finest preserved example of these distinctive round towers is the Broch of Mousa. In 2011, a site known as "the Crucible of Iron Age Shetland", which includes the Broch of Mousa, Old Scatness and Jarlshof, joined the UK's "Tentative List" of World Heritage Sites.History, culture and politics
Pictish times
The culture that built the brochs is unknown, but by the late Iron Age the Northern Isles had become part of the Pictish kingdom. The most common archaeological relics from that period are symbol stones. One of the best examples of these stones is on the Brough of Birsay: It depicts three warriors with spears and sword scabbards, as well as characteristic Pictish symbols. In 1958, a trove of silver metalwork, known as the St Ninian's Isle Treasure, was discovered. The silver bowls, jewellery and other pieces it contains are believed to date from around 800 AD. According to O'Dell, "The treasure is the best survival of Scottish silver metalwork from the period.... he brooches show a variety of typical Pictish forms, with both animal-head and lobed geometrical forms of terminal".Christianity probably arrived in Orkney in the 6th century, and organised church authority emerged in the 8th century. An Ogham–inscribed artefact known as the Buckquoy spindle-whorl was found at a Pictish site on Birsay. There has been controversy about its origin and meaning, but it is now generally considered to be of Irish Christian origin.
Norse era
The 8th century was also the time when the Vikings started invading the Scottish seaboard. They brought to the Northern Isles a new culture and a new language; rendering the fate of the existing indigenous peoples uncertain. According to the Orkneyinga Saga, Vikings then made the islands the headquarters of the pirate expeditions they carried out against Norway and the coasts of mainland Scotland. According to some sources, in 875, the Norwegian king Harald Hårfagre annexed the Northern Isles and gifted Orkney and Shetland to Rognvald Eysteinsson as an earldom in recompense for the death of his son in battle in Scotland.In 995, King Olaf I of Norway fully Christianised the islands by fiat, when he stopped in South Walls on his way from Ireland to Norway. The king summoned the jarl Sigurd the Stout and said, "I order you and all your subjects to be baptised. If you refuse, I'll have you killed on the spot and I swear I will ravage every island with fire and steel." Unsurprisingly, Sigurd agreed, and the islands became Christian at a stroke. In the early 11th century, they received their own bishop.