Tawi Atayr: A sinkhole located in Al-Qarā Mountains Dhofar (more).

More from Tawi Atayr – unfortunately it was the wrong time of day, so shadows in the sinkhole were very dark. It was also before the monsoon hits, so everything is brown & tinder dry.
The metal rusted & broken frame seen on the last image, was for taking water from the bottom of the sinkhole during the summer months. During severe monsoon periods, this place can fill with water, then join the deluge that pours down Wadi Darbat towards the sea; such as when Cyclone Mekunu caused flash flooding earlier this year.

Getting there & seeing the place was great fun (even if rather precarious when venturing near the edge and away from the installed viewing area)  but needs must for photography, as long as one is sensible.

Tawi Atayr: A sinkhole located in Al-Qarā Mountains Dhofar.

 

Two images of a water run-off channel that drops into the Tawi Atayr sinkhole. The one on the right diffused, because I liked the look when printed. On the left I used a lens that has a slight softness around the edges: not everything needs to be ultra sharp.

Tawi Atayr: A sinkhole located in Al-Qarāʾ Mountains Dhofar.

The name roughly translated from Arabic means the “well of the birds” appropriate because it is populated by many birds whose song can be heard seemingly from all directions, when approaching the area of this sinkhole.
Its surface measurement is approximately 130m in a NE-SW direction and about 90m in NW-SE direction with a vertical depth of around 210m. Halfway down it narrows to an almost circular hole of about 60m in diameter.
Opinions differ as to its formation, either erosion exacerbated by fissures opened when the rock freezes or a collapsed cave system.
At the bottom there is a cave passage in a north-eastern direction, located at groundwater level and half-filled with water. To my knowledge, this passage has not yet been explored, it is possible that it leads to Wadi Darbat and the sea which is only 10km to the south.

Al-Hajar Mountains.

Al-Hajar Mountains.

The Al Hajar stretch for about 700 km across the north of the country and rise to over 3,000m (Jebel Shams – mountain of sun) from the coastal plain. Sediments at the core were mainly laid down during the Late Permian to Late Cretaceous in the Tethys ocean basin that had resulted from the break-up of Gondwana.
The Arabian Plate collided with and pushed against the Iranian Plate, resulting in mountains chiefly made of Cretaceous limestones and ophiolites.

Rock outcrops in the Al Hajar Mountains, the Huqf and Dhofar span about 825 million years and includes at least three periods when the country was covered by ice.
Oman, located at the south-east corner of the Arabian plate, is being pushed slowly northward, as the Red Sea grows wider. The Al Hajar Mountains and valleys of Musandam are dramatic reminders of this: Oman is fairly quiescent tectonically but the Musandan experiences occasional tremors as the Arabian Plate collides with the Eurasian Plate (I remember coming back from holiday & finding bathroom tiles all over the floor from one of these tremors).

During the Cretaceous Period Oman was located adjacent to a subduction zone and a portion of the upper mantle along with overlying seafloor volcanic rocks were thrust over the continental crust. This obducted sequence of ultramafic to mafic rocks is the Semail Ophiolite complex. The ophiolite is locally rich in copper and chromite ore.

The interior plains of Oman are of young sedimentary rocks, wadi gravels, dune sands and salt flats. Beneath them is a several kilometre thick stack of older sedimentary rocks that host the country’s hydrocarbon resources.

Links for most of this come from – Encyclopædia Britannica & Wikipedia.

 

Erosion.

ErosionRillenkarren – Erosion of rock during Oman’s wetter phase.

The technical description from my geology book says:

Rillenkarren.- Are forms of dissolution on the surface of the rocks that consist of small channels separated by sharp crests configuring a network of tight more or less parallel gullies next to each other. Its Genesis is linked to the dissolution of the rock by the sheet of water that forms on it as a local run-off.