St. John's Island, Egypt
Encyclopedia
St. John's Island is the largest of a group of islands in Foul Bay
, Red Sea
in Southern Egypt
. It covers an area of 4.50 square kilometres (approx.). It is not a quaternary
volcanic
island, but rather is believed to be an upthrusted part of upper mantle material. The nearest island is Rocky Island. The island is slightly north of the Tropic of Cancer
, and its highest point is 235 metres.
unique as it is uplifted mantle
, a fragment of the sub-Red Sea
lithosphere
. Rocks on the island are mainly lower crust
al metamorphic rock
s. The island became present above sea level after Africa
n and Asia
tic continental plates converged to cause rocks in the lower crust to be uplifted. The island comprises three massives of peridotite
, which are rich in the gemstone peridote (olivine). This gem makes the island notable as it is believed to be the first discovered source of peridot
, which was called topazios in ancient times, hence the Greek
name for the island, Topazios. Layers of spinel-lherzolites with anhydrous
Al-diopside pyroxenites and hydrous Cr-diopside pyroxenites 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.
in October, 1994.
industry on the island. The coral is located approximately 25 metres below the surface
Fish that can be found within the nearby water
s and corals are:
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 to Rocky Island in the south.
Foul Bay
Foul Bay is an inlet of water on the Egyptian side of the Red Sea. It is located slightly north of the Tropic of Cancer. The town which lies at the most inland section of the bay is Berenice. The northern part of Foul Bay is a peninsula called Ras Banas....
, Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
in Southern Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
. It covers an area of 4.50 square kilometres (approx.). It is not a quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
volcanic
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
island, but rather is believed to be an upthrusted part of upper mantle material. The nearest island is Rocky Island. The island is slightly north of the Tropic of Cancer
Tropic of Cancer
The Tropic of Cancer, also referred to as the Northern tropic, is the circle of latitude on the Earth that marks the most northerly position at which the Sun may appear directly overhead at its zenith...
, and its highest point is 235 metres.
Geology
The island is considered geologicallyGeology
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...
unique as it is uplifted mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
, a fragment of the sub-Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
lithosphere
Lithosphere
The lithosphere is the rigid outermost shell of a rocky planet. On Earth, it comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater.- Earth's lithosphere :...
. Rocks on the island are mainly lower crust
Crust
Crust may refer to:* Crust * The Crust, television seriesPhysical sciences:* Crust , at least continent-wide structure* Soil crust, local biology-sensitive structureFood:* Crust, dense surface layer of bread...
al metamorphic rock
Metamorphic rock
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
s. The island became present above sea level after Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
tic continental plates converged to cause rocks in the lower crust to be uplifted. The island comprises three massives of peridotite
Peridotite
A peridotite is a dense, coarse-grained igneous rock, consisting mostly of the minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium, reflecting the high proportions of magnesium-rich olivine, with appreciable iron...
, which are rich in the gemstone peridote (olivine). This gem makes the island notable as it is believed to be the first discovered source of peridot
Peridot
-Chemistry:The chemical composition of peridot is 2SiO4, with Mg in greater quantities than Fe.-Etymology:The origin of the name "peridot" is uncertain...
, which was called topazios in ancient times, hence the Greek
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
name for the island, Topazios. Layers of spinel-lherzolites with anhydrous
Anhydrous
As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another...
Al-diopside pyroxenites and hydrous Cr-diopside pyroxenites 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 FalconSooty Falcon
The Sooty Falcon is a medium-sized falcon breeding from northeastern Africa to the southern Persian Gulf region. It belongs to the hobby group, a rather close-knit number of similar falcons often considered a subgenus Hypotriorchis...
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 divingDiving
Diving is the sport of jumping or falling into water from a platform or springboard, sometimes while performing acrobatics. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.Diving is one...
industry on the island. The coral is located approximately 25 metres below the surface
Fish that can be found within the nearby water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
s and corals are:
- RaysBatoideaBatoidea is a superorder of cartilaginous fish commonly known as rays and skates, containing more than 500 described species in thirteen families...
- MorayMorayMoray is one of the 32 council areas of Scotland. It lies in the north-east of the country, with coastline on the Moray Firth, and borders the council areas of Aberdeenshire and Highland.- History :...
s - OctopusOctopusThe octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
- CrocodilefishCrocodilefishCrocodilefish is the common name given to some members of the family Platycephalidae:*It is the Fishbase recognised name for Cymbacephalus beauforti, the De Beaufort's flathead, a fish occurring in the western Pacific....
- CuttlefishCuttlefishCuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....
Tourism
The island is located near coral reefCoral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
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 to Rocky Island in the south.
External links
- St. John's Island peridot information and history at Mindat.orgMindat.orgMindat.org is a non-commercial online mineralogical database, claiming to be the largest mineral database and mineralogical reference website on the internet....
- Bird Life Information
- Diving Egypt's Marine Park Islands
- Diving Information
- red sea dive safaris covering all the red sea