Dallol (volcano)
Encyclopedia
Dallol is a volcanic explosion crater (or maar
) in the Danakil Depression
, northeast of the Erta Ale Range
in Ethiopia
. It has been formed by the intrusion of basaltic magma in Miocene
salt deposits and subsequent hydrothermal activity. Phreatic eruptions
take place here, the last known one in 1926, numerous other eruption craters dot the salt flats nearby. These craters are the lowest known subaerial
volcanic vents in the world, at over 45 m (150 ft) below sea level.
Numerous hot spring
s are discharging brine
and acidic liquid here. Widespread are small, temporary geyser
s which are forming cones of salt.
The term Dallol was coined by the Afar people
and means dissolution or disintegration describing a landscape made up of green acid ponds (pH
-values less than 1) iron oxide
, sulfur
and salt desert plains. The area resembles the hot springs areas of Yellowstone Park but appears to be more wide-stretching.
Maar
A maar is a broad, low-relief volcanic crater that is caused by a phreatomagmatic eruption, an explosion caused by groundwater coming into contact with hot lava or magma. A maar characteristically fills with water to form a relatively shallow crater lake. The name comes from the local Moselle...
) in the Danakil Depression
Danakil Depression
The Danakil Depression is a desert basin which lies in the Danakil Desert in north-eastern Ethiopia and southern Eritrea. It belongs to the homeland of the Afar people. It lies up to 100 m below sea level as a result of tectonic activity caused by plate movements...
, northeast of the Erta Ale Range
Erta Ale Range
Erta Ale Range is the most important axial volcanic chain of the Afar Depression, Afar Region, Ethiopia. It consists mostly of shield volcanoes. The active volcano Erta Ale is a prominent feature of the range...
in Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
. It has been formed by the intrusion of basaltic magma in Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
salt deposits and subsequent hydrothermal activity. Phreatic eruptions
Phreatic eruption
A phreatic eruption, also called a phreatic explosion or ultravulcanian eruption, occurs when rising magma makes contact with ground or surface water. The extreme temperature of the magma causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash, rock, and...
take place here, the last known one in 1926, numerous other eruption craters dot the salt flats nearby. These craters are the lowest known subaerial
Subaerial
The term subaerial is mainly used in geology to describe events or structures that are located at the Earth's surface...
volcanic vents in the world, at over 45 m (150 ft) below sea level.
Numerous hot spring
Hot spring
A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...
s are discharging brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
and acidic liquid here. Widespread are small, temporary geyser
Geyser
A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...
s which are forming cones of salt.
The term Dallol was coined by the Afar people
Afar people
The Afar , also known as the Danakil, are an ethnic group in the Horn of Africa. They primarily live in the Afar Region of Ethiopia and in northern Djibouti, although some also inhabit the southern point of Eritrea.-Early history:...
and means dissolution or disintegration describing a landscape made up of green acid ponds (pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
-values less than 1) iron oxide
Iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...
, sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
and salt desert plains. The area resembles the hot springs areas of Yellowstone Park but appears to be more wide-stretching.
See also
- List of volcanoes in Ethiopia
- DallolDallol, EthiopiaDallol was a settlement in northern Ethiopia. Located in Administrative Zone 2 of the Afar Region in the Afar Depression, it has a latitude and longitude of with an elevation of about 130 meters below sea level...
- a ghost townGhost townA ghost town is an abandoned town or city. A town often becomes a ghost town because the economic activity that supported it has failed, or due to natural or human-caused disasters such as floods, government actions, uncontrolled lawlessness, war, or nuclear disasters...
in the Dallol crater. It had the record high average temperature for an inhabited location on Earth.