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Research about Libya

Source-linked reports with geographic coverage including Libya.

8 recordsLinked to original sources
USGS1967

Stratigraphic and tectonic framework of Libya

Libya is situated on the Mediterranean foreland of the African shield. Marine strata of Paleozoic, Mesozoic, and Cenozoic ages abound in northern Libya, but continental rocks of Paleozoic and Mesozoic ages predominate in southern Libya. Marine incursions in Ordovician, Silurian, Devonian, Carboniferous, late Cretaceous, and early Tertiary times reached far into the country, some crossing the southern border. Compressional folds are almost wholly absent, but uplift, subsidence, block faulting, and tilting have occurred, and angular and parallel unconformities are common. The major diastrophic disturbances include the Caledonian and Hercynian, as well as disturbances during late Cretaceous and Oligocene through Miocene or Recent times. The chief regional structures are the Gefara basin, Hamada basin, Gargaf arch, Marzuq basin, Tibesti-Haruj uplift, Kufra basin, Cyrenaican uplift, and Sirte embayment. Several large basalt flows of Cenozoic age are present. Sand and gravel conceal the bedrock in about a third of the country. In the Sirte embayment marine sedimentation, differential compaction, reef development, subsidence, and block faulting, beginning in late Cretaceous time, favored the development of source and reservoir rocks. Recoverable oil has been found chiefly in limestone and sandstone of early and late Cretaceous and Tertiary ages, and in knobs of probable early Paleozoic sandstone and in fractured granite. In the Hamada basin oil accumulations have been found in sandstones of Triassic age and of several Paleozoic systems. Most of the oil and gas discovered to date in Libya are in anticlinal structures, but several unconformities within the section probably influenced these accumulations; oil and gas may well await discovery in other types of traps.

AAPG Bulletin↗
USGS1962

Idri salt deposits, Fezzan Province, Libya

The Idri salt deposit, located 135 kilometers west of Brack in the Shatti Valley area of the Fezzan province, United Kingdom of Libya, covers an area of about 35 square Kilometers. It is connected to the newly constructed black-top Fezzan road by about 250 kilometers of secondary road. The deposit is a salt flat that lies in a closed depression. It consists of a hard crust commonly 20 to 40 cm thick overlying 40 cm of salts and wet sand above the brine. The origin of the deposit is attributed to the percolating waters that concentrate into a brine and then by capillary action and evaporation form a crust on the surface. Experiments with fractional crystallization by solar evaporation in the field indicated that fairly pure table salt may be obtained in the first stage of evaporation, and a product containing about 6 percent K 2 0 equivalent may be recovered in the second stage. Laboratory experiments indicate that by the dissolving of the natural crust and recrystallization by artificial heat a salt mixture containing about 7 to 10 percent potassium may be recovered. No future geologic work is recommended for the area but it is suggested that the deposit may be worked on a small scale to recover a pure table salt and, if the conditions warrant, the residual brine may be further treated to recover potash as a by-product.

Fezzan Province↗
USGS1962

Pisida salt deposit, Libya

The Pisida salt deposit, located about 165 kilometers west of Tripoli on the Mediterranean coast, covers an area of about 50 square kilometers in Libya. Thin layers of salts, less than 50 centimeters thick, are deposited on the surface as a result of the evaporation of the percolating sea water which is brought to the surface by capillary action. Halite (NaCl) and sylvite (KCl), the least soluble salts, crystallize at the surface, resulting in a relatively high content of magnesium in the residual brine. The deposits were investigated by collection and analyses of salts and brine samples from 19 test pits and two drill holes. The chemical analyses indicate that small amounts of potassium salts (Average 3.5 percent potassium) occur in the surface evaporites and the brine contains an appreciable amount of magnesium (Average 3 percent magnesium). Cores collected from the two drill holes indicate that the deposits are surficial and no salt stratum occurs at depth. Laboratory experiments indicate that fractional crystallization may be applied to recover potassium and magnesium salts from the brines at Pisida.

Open-File Report↗