|Coordinates:||17.1129 N 54.5603 E|
|No:||139 (list of all attractions)|
|Values:||Geology, Biology, Visual|
|Address:||Asia, Oman, Dhofar Governorate, 46 km NEE from Salalah, north from Tawi Atair village, Qara Mountains|
|Alternate names:||Tawi Atayr, Tawi Ateer, Alsharkh ("the fissure")|
|Depth of sinkhole:||211 m|
Crossection of Tawi Atair sinkhole. Compared with Boeing 747-400.
Gatis Pāvils, basing on Hanna " Al Balushi, 1996, CC-BY-SA-3.0
One of the most impressive sinkholes in Oman is Tawi Atair (often - Tawi Atayr). But this structure is special not only due to its size - deep in its depths there lives unique fish.
Local people earlier believed that the giant hole in Qara Mountains has been created by meteorite. But in reality this gap was formed by groundwater, by karst processes.
Tawi Atair is very impressive limestone formation - at the surface level (680 m above the sea level) it is 140 m across in NE - SW direction and 100 m in NW - SE direction. In lower half it narrows down to 60 m across. Depth of sinkhole is 211 m - like 60 floor high building. Volume - 975,000 m³. Such size is not exceptional - even 8.5 km further to the north-east there is Teiq sinkhole with 90 million m³ volume (one of the largest in world), but nonetheless Tawi Atair is very imposing structure with mostly vertical walls.
Tawi Atair might be formed by a collapse of the roof of giant cave hall but just as well - by gradual widening of fractures in the rock. This area of Oman contains much evidence of karst processes - here are located numerous other smaller sinkholes and many caves.
Walls of sinkhole contain multiple dripstone formations - stalactites, stalagmites and others. These formations are located at different height - they might testify that earlier, when the ceiling of this void was not collapsed, here was cave - and this cave eroded downwards.
Some even believe that the passages of Tawi Atair are connected with Teiq sinkhole.
Trees and birds
Tawi Atair is well known to local people since ancient times. During harsh winters people even lived inside the sinkhole, on the inner edge of this abyss - there the temperature is more or less stable throughout the year.
Name of the sinkhole in Arabic sounds similar to "well of the birds". This name is well suited because there are very many birds living in this sinkhole.
Such explanation though has rised some discussions because next to the sinkhole is village with the same name - some consider that sinkhole was named after the village. Here in turn can be discussed whether the village did not get its name from sinkhole - all over the world settlements get their names from indicative natural landmarks close by.
Sinkhole is popular tourist destination with car parking lot and visitor centre next to it. Birds add special feel to this unusual place - such amount of singing birds is not usual in Oman. Unfortunately the impressive view in most places is blocked by a dense growth of shrubs along the upper rims of the sinkhole.
Cave and unique fish
At the bottom of sinkhole there is a continuation - cave passage in north-eastern direction. This passage is located at groundwater lewel and half-filled with water. Passage under the level of water has not been fully explored yet.
In 1980 in the lake of sinkhole there was found a new species of fish. This fish was named after one of discoverers, well known researcher of Arabian caves Andy Dunsire: Garra dunsirei Banister, 1987. This unique organism lives only in this cave and there are no other freshwater fishes in 600 km radius. Fish has very small eyes, but seems to have weak vision. In the total darkness of cave fish uses tentacles and other senses, not vision. It is pale yellow, some 3 - 6 cm long.
Existence of this fish is important sign - this small fish is relict from the times when climate in this area was different and there were permanent streams and lakes. Fish still has eyes - thus it was not too long ago, when the ancestors of present day cave fishes lived in daylight.