# Fezzan Basin

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Fezzan_Basin
> Markdown URL: https://mediated.wiki/source/Fezzan_Basin.md
> Source: https://en.wikipedia.org/wiki/Fezzan_Basin
> Source revision: 1341263990
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Interior drainage basin in Libya

The **Fazzan Basin**, or **Fezzan Basin**, is a large [endorheic basin](/source/Endorheic_basin) in Libya. It has no outlet to the sea and contains large areas of desert or semi-arid land. It is one of two basins in southern [Libya](/source/Libya) on the northern flanks of the [Tibesti Mountains](/source/Tibesti_Mountains) in the central [Sahara desert](/source/Sahara), the other being the [Kufra Basin](/source/Kufra), further to the east.[1]

## Formation

The Fazzan Basin is situated on the junction between two [tectonic plates](/source/Plate_tectonics). Collision between these occurred in the [Paleozoic](/source/Paleozoic) period and caused thickening of the Earth's crust, which then [downwarped](/source/Isostasy) under its own weight to form a depression in the ground, the Fazzan Basin. Since then, there has been a deposition of "continental intercalaire" and other continental rocks, and large quantities of water have been trapped in underground [aquifers](/source/Aquifer). An outcrop of [basalt](/source/Basalt) occurs between the Fazzan and the Kufra Basins, and both are overlaid by sand.[1]

The climate of this region has varied greatly in the past, with pluvial and dry periods alternating; the current arid phase averages less than 20 mm (0.8 in) of precipitation per year.[2] During its geologic history, the Fazzan Basin has on at least four occasions during the [Pleistocene](/source/Pleistocene) been inundated with water to form a large lake.[2] On each occasion, a thick layer of limestone was deposited. Armitage et al. (2007) estimated that two of these events occurred earlier than 400,000 years ago, another one was in [MIS 11](/source/MIS_11) (~400,000 years ago) and a further one in [MIS 5](/source/MIS_5) (between 130,000 and 80,000 years ago).[2] Geye and Thiedig (2008) recognise further lake sedimentation periods in [MIS 9](/source/MIS_9) and [MIS 7](https://en.wikipedia.org/w/index.php?title=MIS_7&action=edit&redlink=1). They have also estimated that the lake extended to 100,000 km2 (38,610 mi2) in MIS 11, and this was when it was at its maximum size. By MIS 5, the lake was reduced to 1,400 km2 (541 mi2) and less than 100 km2 (39 mi2) during the most recent iteration in the [Holocene](/source/Holocene).[3] However, Armitage et al. (2007), citing Brooks et al. (2003), put the Holocene lake area at 76,250 km2 (29,440 mi2).[4] Although there is some disagreement about the exact timing and the size of Lake Megafazzan, both authorities agree that there has been no [lacustrine](/source/Lacustrine_deposits) activity between MIS 5 and the Holocene. The MIS 5 deposits include fossils of *[Cerastoderma glaucum](/source/Cerastoderma_glaucum)*, which indicates that the water was probably [brackish](/source/Brackish_water).[4]

## Lake Megafazzan

During the [Miocene](/source/Miocene), Libya was drained by two large rivers systems, both flowing into the [Mediterranean Sea](/source/Mediterranean_Sea), the [Wadi Nashu](https://en.wikipedia.org/w/index.php?title=Wadi_Nashu&action=edit&redlink=1) River in the west and the [Sahabi River](https://en.wikipedia.org/w/index.php?title=Sahabi_River&action=edit&redlink=1) in the centre and east. In the late Miocene and early [Messinian](/source/Messinian), increased volcanic activity in northeastern Libya resulted in the damming back of the Wadi Nashu, which caused water to accumulate in the Fazzan Basin, forming the proto-Lake Megafazzan during humid periods.[5]

## References

1. ^ [***a***](#cite_ref-Bridges_1-0) [***b***](#cite_ref-Bridges_1-1) Bridges, Edwin Michael (1990). [*World Geomorphology*](https://books.google.com/books?id=-ZCyyxIZPaIC&pg=PA41). Cambridge University Press. pp. 41–42. [ISBN](/source/ISBN_(identifier)) [978-0-521-28965-8](https://en.wikipedia.org/wiki/Special:BookSources/978-0-521-28965-8).

1. ^ [***a***](#cite_ref-Armitage_2-0) [***b***](#cite_ref-Armitage_2-1) [***c***](#cite_ref-Armitage_2-2) Armitage, S.J.; Drake, N.A.; Stokes, S.; El-Hawat, A.; Salem, M.J.; White, K.; Turner, P.; McLaren, S.J. (2007). "Multiple phases of North African humidity recorded in lacustrine sediments from the Fazzan Basin, Libyan Sahara". *Quaternary Geochronology*. **2** (1–4): 181–186. [doi](/source/Doi_(identifier)):[10.1016/j.quageo.2006.05.019](https://doi.org/10.1016%2Fj.quageo.2006.05.019). [hdl](/source/Hdl_(identifier)):[2381/11455](https://hdl.handle.net/2381%2F11455).

1. **[^](#cite_ref-3)** Geyh, Mebus A.; Thiedig, Friedhelm (2008). "The Middle Pleistocene Al Mahrúqah Formation in the Murzuq Basin, northern Sahara, Libya evidence for orbitally-forced humid episodes during the last 500,000 years". *Palaeogeography, Palaeoclimatology, Palaeoecology*. **257** (1–2): 1–21. [doi](/source/Doi_(identifier)):[10.1016/j.palaeo.2007.07.001](https://doi.org/10.1016%2Fj.palaeo.2007.07.001).

1. ^ [***a***](#cite_ref-Hublin_4-0) [***b***](#cite_ref-Hublin_4-1) Smith, J. R. (2012). "Spatial and Temporal Variation in the Nature of Pleistocene Pluvial Phase Environments Across North Africa". In Hublin, Jean-Jacques; McPherron, Shannon P. (eds.). [*Modern Origins: A North African Perspective*](https://books.google.com/books?id=GyYt3Ogx5AQC&pg=PA38). Springer Science & Business Media. pp. 38–39. [doi](/source/Doi_(identifier)):[10.1007/978-94-007-2929-2_3](https://doi.org/10.1007%2F978-94-007-2929-2_3). [ISBN](/source/ISBN_(identifier)) [978-94-007-2929-2](https://en.wikipedia.org/wiki/Special:BookSources/978-94-007-2929-2).

1. **[^](#cite_ref-Drake_5-0)** Drake, N.A.; El-Hawat, A.S.; Turner, P.; Armitage, S.J.; Salem, M.J.; White, K.H.; McLaren, S. (2008). "Palaeohydrology of the Fazzan Basin and surrounding regions: The last 7 million years". *Palaeogeography, Palaeoclimatology, Palaeoecology*. **263** (3–4): 131–145. [doi](/source/Doi_(identifier)):[10.1016/j.palaeo.2008.02.005](https://doi.org/10.1016%2Fj.palaeo.2008.02.005).

---
Adapted from the Wikipedia article [Fezzan Basin](https://en.wikipedia.org/wiki/Fezzan_Basin) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Fezzan_Basin?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.