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Geology

Geology

For rock buffs, St Helena is geomorphology heaven. The gigantic rock formations and lava flows near the bottom are breathtaking, as are some coloured sand dunes. The unworldly geology and contrasting landscapes is breathtaking.

 

The riotous shapes of the formations have earned them the names like “Lot’s Wife”, “Asses Ears” and “The Barn”.

 

Geologists will tell you there is nothing like St Helena on the planet. Charles Darwin, inspired by Seale’s drawings, visited the island on the voyage of the HMS Beagle, and wrote a chapter on St Helena in his ‘Geological Observations on the Volcanic Islands’ (Darwin, 1844).

 

St Helena is very three-dimensional. It probably has more miles of ridges, gullies, valleys, ravines and gulches per unit area of land than anywhere else in the world, certainly more than on any other island. Now imagine a sky with a checkerboard of clouds and azure, and sunlight shining through the cloud breaks. This is a moveable feast for the eyes, a photographer’s paradise.

 

St Helena’s landscape and geology are without equal among islands of the world. The few built-up areas are unchanged since Georgian times. Like some other isolated locations, this lonely island in its early years was used as a place of exile for felons or war prisoners, the most celebrated of whom was Napoleon. Forts were built to spot outsiders who were helping prisoners, plotting escape.

 

Landscape and scenery are ‘spectacular’, ‘unsurpassed’ and ‘edenesque’. The peak of an extinct volcano, only 47 square miles in surface area, just to the east of the Mid-Atlantic Ridge, the island in fact has some of the most diverse scenery in the world.

 

The island’s interior must have been a dense subtropical forest but the coastal areas were probably quite green as well. The modern landscape is very different, with a lot of naked rock in the lower areas, and a high interior that is green, mainly due to imported vegetation. The dramatic change in landscape must be attributed to the introduction of goats and the introduction of new vegetation. As a result, the string tree (Acalppha rubrinervis) and the St Helena olive (Nesiota elliptica) are now extinct, and many of the other endemic plants are threatened with extinction.

 

The highest point on St Helena is Diana’s Peak (2,685 ft. / 823 m). On the higher central ground, bush and semi-tropical vegetation is abundant. This changes to grassland and pastures before the terrain becomes drier and almost barren below 500m to the sea. The only inland waters are small mountain streams, which occasionally dry up in the summer months.

 

 

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