The geology of Algeria is diverse; the country divides into three different tectono-stratigraphic domains. In the south and west is the

West African Craton The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.Jessell M.W., Liégeo ...

which consists of Precambrian

granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...

basement and surrounding

Neoproterozoic The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is prec ...

mobile belts. Further south the Tuareg Shield comprises the

Hoggar The Hoggar Mountains ( ar, جبال هقار, Berber: ''idurar n Ahaggar'') are a highland region in the central Sahara in southern Algeria, along the Tropic of Cancer. The mountains cover an area of approximately 550,000 km. Geography Thi ...

, Adrar des Iforas and

Air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...

sub-shields which have each been affected by tectono-thermal events touching much of the continent. In the north are the Alpine chain mountains with a succession of folded and over-thrust strata.

Economic geology

The production of oil and gas is important to

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

's economy, being Africa's main producer of the latter. Its reserves were estimated at 4.502 trillion m³ at the end of 2008. Productive fields are found in

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

s, faulted anticlines or domes; the reservoirs being in Cambro-

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

, Devonian, and Carboniferous

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

Caprock Caprock or cap rock is a more resistant rock type overlying a less resistant rock type,Kearey, Philip (2001). ''Dictionary of Geology'', 2nd ed., Penguin Reference, London, New York, etc., p. 41.. . analogous to an upper crust on a cake that is ha ...

s include Triassic

evaporite An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocean ...

s and Carboniferous to Devonian shales. The major source rocks for the

hydrocarbons In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or e ...

were Silurian shales rich in organic material. In 2008, Algeria was the fourth-largest oil producer in Africa accounting for about one-sixth of the continent's production. The country's proven reserves of crude petroleum are out at 1.66 billion tonnes, or about 1 percent of the global reserve.

Geohazards

In Northern Algeria, earthquakes occur frequently, damaging infrastructure and property, as well as causing human loss of life. The

1980 El Asnam earthquake The 1980 El Asnam earthquake occurred on October 10 at with a moment magnitude of 7.1 and a maximum Mercalli intensity of X (''Extreme''). The shock occurred in the Algerian town of El Asnam (now known as Chlef). The shocks were felt over awa ...

caused 2,600 deaths and left 300,000 homeless. The search for hydrocarbons has also induced pollutants into aquifers and groundwater.

References

{{Africa topic, Geology of

Economic geology

Geohazards

See also

References