Mundafan
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| Mundafan | |
|---|---|
_overlain_upon_the_palaeohydrological_reconstruction_of_the_Mundafan_area.png) | |
  Mundafan | |
| Coordinates | 18°34′N 45°20′E / 18.56°N 45.34°E |
| References | [1] |
Mundafan was a former lake in Saudi Arabia, within presently desert-like areas. It formed during the Pleistocene and Holocene, when orbitally mediated changes in climate increased monsoon precipitation in the peninsula, allowing runoff to form a lake with a maximum area of 300 square kilometres (120 sq mi). It was populated by fishes and surrounded by reeds and savanna, which supported human populations.
Mundafan is a lies in the Najran Province of Saudi Arabia, southwest of the Rub' al Khali desert.[2] The climate of the region is arid to hyperarid, with sand and stone deserts dominating the landscape.[3] The name Arabic: Ramlat al-Mundafan means "the buried sands".[4]
The perennial[5] lake had an elongated shape in northwest–southeast direction[6] and reached a maximum depth of 30 metres (98 ft)[7] and extent of 300 square kilometres (120 sq mi) during stages of high water levels,[8] making it one of the largest former lakes of Arabia.[1] It is possible that it was not one contiguous water body, but rather several separate lakes or an extended wetland. The lake was fed by wadis coming from the Asir Mountains to the west[7] and contained freshwater,[9] although there is also evidence for brackish water.[10] Carbonate sediments formed when parts of the lake bed fell dry.[11]
Mussels (Unio), snails (Biomphalaria and Radix), sponges and submerged stoneworts (a type of algae) lived in the lake, which was fringed by reeds (Phragmites and Typha),[5] sedges and marshes.[12] Indirect evidence attests to the existence of fish in the lake.[13] Riparian forests and savannah environments developed around the lake,[14] with trees including possibly palms. Wildfires occasionally burned in the area. The environment was suitable for humans[7] and Mundafan was an important hunting ground for early humans.[15] Aurochs, camels, wild cattle, gazelles, wild goats, hartebeest, hippopotamuses, horses, ostriches, tahr, water buffalo, wild sheep and wild asses lived around the Mundafan lake.[14][10]
The lake has left sediments made out of clays, marls and silts that form benches and mounds.[2] The sediments reach thicknesses of 24 metres (79 ft).[16] The sparseness of lake deposits has led to some researchers to doubt that the waterbodies were lakes rather than wetlands, but circumstantial fossil evidence strongly implies that the waterbodies were true lakes and that the rarity of lake landforms is primarily a consequence of wind erosion, which removed these landforms after the lakes had dried up.[12]
The Mundafan lake formed in a c. 363 square kilometres (140 sq mi) topographical depression formed by wind deflation. To the east rises the Tuwaiq Escarpment, a limestone of Jurassic age.[2] The lake lies within a former river bed that was blocked by dunes[7] or perhaps faulting[17] and might have overflowed northwards if its surface area exceeded 346 square kilometres (134 sq mi).[1] The catchment of the Mundafan lake is comparatively large, leading to the formation of long-lasting (at least 800 years) lakes and the thickest lake deposits of Arabia.[10]
