The Gialo High is a relatively small horst block in the eastern

Sirte Basin The Sirte Basin is a late Mesozoic and Cenozoic triple junction continental rift (extensional basin) along northern Africa that was initiated during the late Jurassic Period. It borders a relatively stable Paleozoic craton and cratonic sag basins a ...

of the

Libya Libya (; ar, ليبيا, Lībiyā), officially the State of Libya ( ar, دولة ليبيا, Dawlat Lībiyā), is a country in the Maghreb region in North Africa. It is bordered by the Mediterranean Sea to the north, Egypt to Egypt–Libya bo ...

n oil fields. It is most important and best known for the stacked

oil field A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...

s in rocks ranging from

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

age. There are several billion barrels of

oil reserves An oil is any polarity (chemistry), nonpolar chemical substance that is composed primarily of Hydrocarbon, hydrocarbons and is hydrophobe, hydrophobic (does not mix with water) & lipophilicity, lipophilic (mixes with other oils). Oils are usu ...

associated with the structure both over the crest of the horst as well as flanking the high in the adjacent

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

Present day explorers

There are three oil companies currently exploring for and producing oil from the Gialo High and the surrounding flanks.

Wintershall Wintershall Holding GmbH, based in Kassel, was Germany's largest crude oil and natural gas producer. It was a wholly owned subsidiary of BASF. The company was active in oil and gas exploration and production with operations in Europe, North Afr ...

operates Concession 97,

Waha Oil Company Waha Oil Company (WOC; Arabic: , ) is an oil company based in Tripoli, Libya, engaged in the fields of crude oil and natural gas exploration and production. Overview WOC is involved in upstream activities, including oil exploration, drilling, ...

operates Concession 59 and the

Arabian Gulf Oil Company The Arabian Gulf Oil Company (Agoco; ar, شركة الخليج العربي للنفط) is an oil company based in Benghazi, Libya, engaged in crude oil and natural gas exploration, production and refining. It was a subsidiary of the state-owned ...

(Agoco) operates NC59. Some of the

oil fields A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...

on the Gialo High and its flanks are Gialo, 6J-59, 4E-59 and Lidam. Geography of Libya Oil fields of Libya Horsts (geology) {{Oilfield-stub