The North Atlantic rolls towards Europe across the Rockall Bank and a deep water basin 2500 metres deep before hitting the Hebrides off the west coast of Scotland. These ancient islands and mainland Scotland once sat on the equator and are surrounded by shallow bays and inlets with golden to white sand beaches ranging in size from the personal to miles long with crystal clear turquoise water and translucent waves to rival those found in places like Hawaii. A landscape fashioned by geology, the Hebrides and Scotland are a tourist distanation, attracting nature and animal lovers from around the world.
The main chain of the Outer Hebrides, from Berneray to Lewis, is made up of some to the oldest rocks in Europe. They have been know as the 'Lewisian gneisses' since the late 19th century and are named after the lsle of Lewis. They also occur in the north-western part of the Scottish mainland, between Skye and Cape Wrath.
Lewisian gneisses is used to describe a complex series of rocks that occurred over a period of 1500 million years, about a third of the history of Earth. Parts of the isles of Harris and Uist are of a particular type of igneous rock known as anorthosite, which is almost entirely feldspar. Anorthosite is rare in Britain, but is very common on the Moon, where it makes up a large proportion of the 'lunar highlands'.
Around 60 million years ago, large scale tectonic movements led to the crust of Scotland being stretched and thinned. This was particularly intense along what is now the western coast of Scotland. Volcanoes where formed and the evidence of lava flows can be seen on the islands of Skye and Mull. Some of the lava cooled underwater and in cracks forming dykes and columns such as the Great Causeway in Ireland, the Shiant Isles and St. Kilda.
After the eruption of the Scottish volcanoes, the continental crust to the west of Scotland split completely and magma erupted to form new ocean floor, and the birth of the North Atlantic Ocean.
Over the last 500 million years Scotland has travelled from the tropics to the near arctic, been covered by glacial periods 3 times, the last of these around 22,000 years ago. The Ice Age's have left an indelible imprint on the landscape of the Hebrides and Western Scotland, creating a rugged and desolate beauty of frost-shattered blocks of rocks, jagged pinnacles and tors, lochs and smooth granite mountain tops.
Profound changes in the landscape were brought about 11,500 years ago by the sudden switch from a severe, dry Arctic climate to a relatively warm, wet one dominated by the Gulf Stream. Herbaceous plants soon began to colonize the thin, stony soils, followed by heather, juniper, grass, birch scrubland, mixed hazel and oak until around 8,000 years ago. Mesolithic Man began to reduce the forest cover and peat began to form when the climate became cooler and wetter around 6,000 years ago.
The coastal grasslands that back many of the long, white sandy beaches along the western seaboard of the Outer Hebrides are particularly rare habitats in Europe and are know as machair. Most machair areas include a mosaic of migrating dunes, long-stabilised dune fields and partially eroded plateaux. Brackish lagoons, freshwater lochans and bogs associated with the machair provide a wealth of different habitats for plants, birds, and other animals. The natural and cultural landscapes of the Outer Hebrides are heavily influenced by the cool, moist, maritime climate with its heavy rainfall, strong westerly winds and general absence of prolonged frost and snow. Flooding is inevitable in the autumn and winter whilst drought is common in early summer.
The Outer Hebrides and Western Scotland is some of the most beautiful and scenic landscape any where on the planet, but also a very delicate bio sphere that can damaged or destroyed by overuse, miss-management and neglect, so my personal plea is for everyone that visits please take care of it, respect the dunes, keep to designated parking and camping places or ask for permission, stay on foot paths or tread carefully and carry out what you carry in.
