Dassen Island
Encyclopedia
Dassen Island is a South Africa
n island in the Atlantic Ocean
. It is situated about 10km west of Yzerfontein
and 55km north of Cape Town
. The flat and low-lying island
measures about 3.1 km long northwest-southeast, and 1 km wide, with an area of 2.73 km² . It is a proclaimed nature reserve
.
The geological
structure of the island is composed of a fine-grained tourmaline granite
(with a few areas of biotite granite) outcrop covered with sand
. Some of the granite features along the shore - to just above the high-water mark - consists of large, rounded boulders which stick out above the sand. Although temporary pans form during the winter in the interior, there is generally little fresh water on the island.
Except on its eastern side, Dassen Island is surrounded by reef
s and consequently many ships have run aground here.
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
n island in the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. It is situated about 10km west of Yzerfontein
Yzerfontein
Yzerfontein is a small harbour town with about 1200 inhabitants on the west coast of South Africa about 90 km north of Cape Town. The main sources of income are tourism , and fishing....
and 55km north of Cape Town
Cape Town
Cape Town is the second-most populous city in South Africa, and the provincial capital and primate city of the Western Cape. As the seat of the National Parliament, it is also the legislative capital of the country. It forms part of the City of Cape Town metropolitan municipality...
. The flat and low-lying island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...
measures about 3.1 km long northwest-southeast, and 1 km wide, with an area of 2.73 km² . It is a proclaimed nature reserve
Nature reserve
A nature reserve is a protected area of importance for wildlife, flora, fauna or features of geological or other special interest, which is reserved and managed for conservation and to provide special opportunities for study or research...
.
The geological
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
structure of the island is composed of a fine-grained tourmaline granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
(with a few areas of biotite granite) outcrop covered with sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
. Some of the granite features along the shore - to just above the high-water mark - consists of large, rounded boulders which stick out above the sand. Although temporary pans form during the winter in the interior, there is generally little fresh water on the island.
Except on its eastern side, Dassen Island is surrounded by reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
s and consequently many ships have run aground here.