- St. John's Island, Egypt
St. John's Island (also known as Zagbargad, Zebirget, Topazios) is the largest of a group of islands in
Foul Bay ,Red Sea in SouthernEgypt . It covers an area of 4.50 squarekilometres (approx.). It is not aquaternary volcanic island, but rather is believed to be an upthrusted part of upper mantle material. The nearest island isRocky Island . The island is slightly north of theTropic of Cancer , and its highest point is 235metre s.Geology
The island is considered geologically unique as it is uplifted mantle, a fragment of the sub-
Red Sea lithosphere . Rocks on the island are mainly lowercrust almetamorphic rocks. The island became present above sea level afterAfrica n andAsia tic continental plates converged to cause rocks in the lower crust to be uplifted. The island comprises three massives ofperidotite , which are rich in the gemstone peridote = olivine. This gem makes the island notable as it is believed to be the first discovered source ofperidot , which was called topazios in ancient times, hence the Greek name for the island, "Topazios". Layers ofspinel-lherzolites withanhydrous Al-diopside pyroxenite s andhydrous Cr-diopside pyroxenite s can be found too on the island. The presence of all of these minerals has led to mining on the island which dates back as early as ancient times.Nature
The island is part of the
Elba National Park meaning the island is conserved. However, the island was closed to the public for one year due to damage to corals and the disturbance of birds who breed on the island.Birds
The island serves as a breeding ground for at least 9 known species of birds. The most recent discovery was that of 150 pairs of
Falco concolor (Sooty Falcon in October, 1994.Plantlife
Vegetation on St. John's Island is very hard to find. Due to the island's lack of soil and infertile rocks, plants have nowhere to grow.
Corals & sealife
The corals surround the island and act as a barrier for the fish and other sea life which live among it. However, the corals recently became damaged due to increased tourist activity and the expansion of the
diving industry on the island. The coral is located approximately 25 metres below the surfaceFish that can be found within the nearby
water s and corals are:
*Rays
*Moray s
*Octopus
*Crocodilefish
*Cuttlefish Tourism
The island is located near
coral reef s which serve as a popular diving attraction for tourists. The diving industry on the island has increased as well as the tourism industry on the island in general resulting in the construction of hotels and diving shelves. The beaches are often quiet and are relatively unspoilt by development. However, most tourists go to this island as a "stop-off" before going toRocky Island in thesouth .External links
* [http://giantcrystals.strahlen.org information about the geology and peridote mining]
* [http://www.birdlife.org/datazone/sites/?action=SitHTMDetails.asp&sid=6205&m=0 Bird Life Information]
* [http://www.h2odive.co.uk/destination/Egypt's_Marine_Park_Islands.html Diving Egypt's Marine Park Islands]
* [http://www.scuba-diving-safaris.co.uk/destinations/egypt/red_sea_marine_parks.htm Diving Information]
* [http://www.seaqueens.com red sea dive safaris covering all the red sea]
Wikimedia Foundation. 2010.