| Actual Image
Staffa - or Goodbye North America (18)
Jamesp
![Gold Star Critiquer/Gold Note Writer [C: 1351 W: 0 N: 5494]](http://i1.treknature.com/misc/g-n-g.gif) (16524) | For an explanation of the title, read the last paragraph. I took this and the workshop picture on a boat trip to Staffa and the Treshnish Islands. So, as usual, conditions were not perfect – rocky boat and bright, but overcast sky.
Staffa (Old Norse for stave or pillar island) is an island of the Inner Hebrides in Argyll and Bute, Scotland. The Vikings gave it this name as its columnar basalt reminded them of their houses, which were built from vertically placed tree-logs.
Staffa lies about 10 kilometres (6 mi) west of the Isle of Mull. The area is 33 hectares and the highest point is 42 metres (135 ft) above sea level.
The island came to prominence in the late eighteenth century after a visit by Sir Joseph Banks. He and his fellow travellers extolled the natural beauty of the basalt columns in general and of the island's main sea cavern which Banks re-named 'Fingal's Cave'. The most famous feature on Staffa. This is a huge sea cave near the southern tip of the island some 20 m high and 75 m long formed in cliffs of hexagonal basalt columns. This cliff-face is called the Colonnade or The Great Face and it was these cliffs and its caves that inspired Felix Mendelssohn's Die Hebriden (English: Hebrides Overture opus 26), which was premiered in London in 1832. The original gaelic name for Fingal's Cave is An Uamh Bhin - 'the melodious cave' - but it was subsequently renamed after the 3rd century Irish warrior Fionn MacCool. Mendelssohn was nonetheless inspired by the sound of the waves in the cave and waxed lyrical about his visit, claiming that he arrived in Scotland: "with a rake for folk-songs, an ear for the lovely, fragrant countryside, and a heart for the bare legs of the natives.
Staffa is entirely of volcanic origin. It consists of a basement of tuff, underneath colonnades of a black fine-grained Tertiary basalt, overlying which is a third layer of basaltic lava lacking a crystalline structure. By contrast, slow cooling of the second layer of basalt resulted in an extraordinary pattern of predominantly hexagonal columns which form the faces and walls of the principal caves. The lava contracted towards each of a series of equally spaced centres as it cooled and solidified into prismatic columns. The columns typically have three to eight sides, six being the modal number. The columns are also divided horizontally by cross joints. Similar formations are found at the Giant's Causeway In Ireland, on the island of Ulva and Ardmeanach on the Isle of Mull. Grooves in the roof of MacKinnon's cave indicate either a pyroclastic flow or a series of eroded ash falls in the rock above the columnar basalt. The 'Staffa Group' is the name given to the series of olivine tholeiite basalts found in the vicinity of Mull which erupted 55-58 million years ago.
The most important fact, however, is that the volcanic activity was due to the opening of the Mid-Atlantic Ridge and the separation of Eurasia and North America. Originally, the Appalachians formed a continuous – much higher mountain range, with the mountains of Northern Ireland, Scotland and Norway. |
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