Aloba Arch
Encyclopedia
Aloba Arch is the name of a natural arch
located in the Africa
n nation of Chad
. Large natural arches are somewhat rare outside of the Colorado Plateau
of the southwest United States
, although it is unknown if this is a true reflection of the geology
or simply because many areas rich in sandstone
, a key ingredient for arches, are not nearly well explored as the Colorado Plateau.
Aloba Arch is considered to be the longest known natural arch outside of the United States, and the only known arch with a span exceeding 200 feet outside of the Colorado Plateau. Due in part to its location as well as being only recently recognized for its size, estimates based on photography yield an approximate span of 77 meters (250 feet). If verified, this would make Aloba the longest natural arch outside of the US state of Utah
, displacing Wrather Arch
in northern Arizona
, which has a verified span of 246 feet.
Chad's Ennedi Range
, located with in the Sahara Desert in the northeast part of the country near Libya
and Sudan
has a geology similar to the Colorado Plateau and has produced a number of natural arches and similar landforms, although only Aloba can claim to be on the top ten list of longest arches in the world. Perhaps more striking than the span, however, is the sheer height of the arch. At 120 meters (394 feet) tall, it towers over the more famous Rainbow Bridge
and is undoubtedly one of the tallest known arches in the world.
Natural arch
A natural arch or natural bridge is a natural geological formation where a rock arch forms, with an opening underneath. Most natural arches form as a narrow ridge, walled by cliffs, become narrower from erosion, with a softer rock stratum under the cliff-forming stratum gradually eroding out until...
located in the 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 nation of Chad
Chad
Chad , officially known as the Republic of Chad, is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest, and Niger to the west...
. Large natural arches are somewhat rare outside of the Colorado Plateau
Colorado Plateau
The Colorado Plateau, also called the Colorado Plateau Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. The province covers an area of 337,000 km2 within western Colorado, northwestern New Mexico,...
of the southwest United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, although it is unknown if this is a true reflection of the geology
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...
or simply because many areas rich in sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
, a key ingredient for arches, are not nearly well explored as the Colorado Plateau.
Aloba Arch is considered to be the longest known natural arch outside of the United States, and the only known arch with a span exceeding 200 feet outside of the Colorado Plateau. Due in part to its location as well as being only recently recognized for its size, estimates based on photography yield an approximate span of 77 meters (250 feet). If verified, this would make Aloba the longest natural arch outside of the US state of Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, displacing Wrather Arch
Wrather Arch
Wrather Arch is the name of a natural arch in north Arizona. It is located in the eponymous Wrather Canyon, a small tributary of the Paria Canyon, which is itself an important tributary of the Colorado River...
in northern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, which has a verified span of 246 feet.
Chad's Ennedi Range
Ennedi Plateau
The Ennedi Plateau, located in the North-East of Chad, in the Bourkou-Ennedi-Tibesti Region, is a sandstone bulwark in the middle of the Sahara. It is assailed by the sands on all sides, that encroach the deep valleys of the Ennedi...
, located with in the Sahara Desert in the northeast part of the country near Libya
Libya
Libya is an African country in the Maghreb region of North Africa bordered by the Mediterranean Sea to the north, Egypt to the east, Sudan to the southeast, Chad and Niger to the south, and Algeria and Tunisia to the west....
and Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
has a geology similar to the Colorado Plateau and has produced a number of natural arches and similar landforms, although only Aloba can claim to be on the top ten list of longest arches in the world. Perhaps more striking than the span, however, is the sheer height of the arch. At 120 meters (394 feet) tall, it towers over the more famous Rainbow Bridge
Rainbow Bridge National Monument
Rainbow Bridge National Monument is administered by Glen Canyon National Recreation Area, southern Utah, USA. Rainbow Bridge is often described as the world's highest natural bridge. The span of Rainbow Bridge was reported in 1974 by the Bureau of Reclamation to be , but a laser measurement in...
and is undoubtedly one of the tallest known arches in the world.