Al Sharquiya Woodlands, Khaluf, Rudist Reef and Qarat Kibrit

October 2008 (English only)

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With a relatively early Eid Holiday we decided to stay close to the coolness of the coast, exploring magnificent ancient woodlands along the eastern flank of the Al Sharquiya (Wahiba) Sands crossing through the dunes to Hij and Mahout. Further to the unspoilt white dunes south of Khaluf and ending with a spurt through the Huqf. 


A drive along the woodlands and eastern coast of the Al Sharquiya Sands

Recently a desert road is being built connecting Al Ashkarah to Shannah (ferry to Masirah), Hij and Mahout. So what used to be difficult may become an easy drive, but for the time being you need to prepare for sand.

we did it the old way anyhow, avoiding the new road and taking the Bedouin tracks. This takes you through the heart of this surprising desert area, varying from dense woodlands through superb dunes plunging with steep cliffs into the sea to flat wind-blown sabkha and salt flats that characterise the area to the north of Bar Al Hickman.

How to get there

Take the Sultan Qaboos motorway from Muscat in direction of Seeb and subsequently Nizwa, turning off to Sur near BidBid. This road winds through the mountains to Ibra and from there to the northern edge of the Al Sharquiya Sands at Al Mintrib. Be careful; cars tend to overtake even where there is no clear view ahead, which is mostly the case. Keep going on along the northern and subsequently eastern side of the sands heading down to Al Kamil. From there it all becomes track-driving.

The full Google Earth Track as shown below is attached here (Google Earth kmz file).
 


A tour of approximately 1400 km

The Al Sharquiya Sands (Wahiba Sands)

The Sharquiya Sands, previously known as the Wahiba Sands comprise a piece of desert as most people image deserts should be, with lots of sand. Yet relatively small, covering approximately 12,000 square kilometers in the east of Oman, just south of the eastern Al Hajar Mountains and with its sand dunes directly bordering the Arabian Sea to the east.

 Perhaps small as deserts go, yet still impressive when facing this sea of sands, with north-south elongated wave like dunes dominating the scenery. The north and central areas of the Sands are characterized by long -up to 30 km- sand mega-ridges, some 100 meters high and about a kilometer wide. Their local Bedouin name is ‘habl’ or rope, an obvious reference to their shape. The sands are here reddish in colour, caused by an iron-oxide coating that has taken many centuries to form. Closest to the mountains they are also becoming richer in ophiolite material. Carbonate grains in the sands also suggest sources from the Oman Mountains. The northern boundary of the sands is abrupt with wadi Batha sharply eroding the sand ridges. The southern part is characterized by light, almost white sands with lower linear dunes, sand sheets, and sabkha fields. The sands are much richer in quartz and carbonate grains indicate coastal sources.

The Sharquiya Sands were first studied in detail by the Royal Geographical Society (RGS) in 1985 and 1986. This was probably one of the largest desert research projects ever with 32 sub-projects covering geology, water, population, animal and plant life with 30 scientists, and hundreds of support personnel. This work laid the foundations for the understanding of the development of the sands and the underlying fossilized sand dunes. These are known as ‘aeolionites’, which are essentially aeolian (wind blown) sands kitted together by carbonate cements forming a rock. The Sharquiya aeolionite is the largest of its kind in the world. From the extensive Royal Geographical Society study in 1985-86 and a steady stream of subsequent studies, it has become clear that the large linear dunes of the north and central Sharquiya Sands are out of sink with the current climatic conditions. They were formed during past high-latitude glaciations when much stronger winds prevailed. The glaciations were associated with a global lowering of sea level and decreased monsoon intensity, exposing large parts of the Eastern Arabian Shelf along the Arabian Sea. The strong winds had free game, blowing coastal sands from this exposed shelf essentially northward and depositing the sands in large linear dunes. Aeolian sediment transport and deposition was eased by the absence of stabilizing vegetation during the glacial-arid conditions.

Smaller dune systems migrate across the larger dunes and dominate the south of the Sharquiya Sands. These are responding to the current wind circulation patters that have a seasonal variation. During the January-to-March (‘Winter’), the NE Monsoon blows from Asia. Weak, but very dry winds curl round the eastern Al Hajar Mountains, resulting in a blow from the east across the sands. These are the winds that cause the development of the west-facing slip faces. During March-to-July (‘Summer’) associated with strong, southwesterly (dry) Monsoon winds, a branch of which blows north across the Sharquiya Sands, the dunes' main slipfaces shift northeastward with changes in overall shape as well.

The latest study of the sands uses high-tech, ground penetrating radar to image the internal build-up of the dunes. The electromagnetic waves reflect from interfaces between slight differences in the dunes providing a detailed three-dimensional image, showing how they shaped over time.

The droplet shape of the Al Sharquiya Sands (formerly known as the Wahiba Sands) with big north-south elongated ridges gradually decreasing in size as the Sands narrow southwards. Notice the dark coloured sands in the northern part, rich in ophiolite material derived from the mountains directly north. The southeastern trending bed of Wadi Batha sharply erodes the sand ridges along the northern edge. The dunes are hiding older cemented aeolian sandstones below. These were blown some 300,000 years ago on the extensive alluvial fans that flank the Al Hajar Mountains to the south, extending over 200km away. The white areas of these fans consist of Mg-dolomite; breakdown products of the ophiolite material. The ophiolites can be recognized as the large dark patches along the Al Hajar range. The whiter sands in the southern and western parts of the Sharquiya Sands originate from coastal sources during high latitude glaciations when sea-level was lower than today, exposing the shelf directly east and southeast and by winds that were much stronger than today

Our campsite on the first day was a secluded area in the fork of two dunes, but it turned-out more popular than we thought, only 200m away from an old water well. It appeared we had a full local football club, or something similar, interested in us visitors. All very friendly as one would expect in such an Eid Holiday.

The western side of the Wahiba Sands has many similar ancient water wells, but there are none in the interior of the Sands. This is part of an area known as 'wadi' Ubaidha already described by Betram Thomas in 1928 to the Royal Geographical Society. His description captures the essence of this area that has remained essentially unchanged except for the Toyota's parked next to the Bedouin homes.

To see the woodlands, or 'ghaf jungle' as Thomas referred to them, was the main reason for taking this route down south of the Wahiba's and it was well worth the effort. 

Prosopis Cineraria, known by the Bedouin as the Ghaf tree is a drought-resistant, acacia-like tree that forms woodland in the western and eastern margins of the Sands. The taproots of mature trees can penetrate as deep as 30 meters and it easily propagates new shoots from parent root systems. The tree also absorbs moisture from dew and mist carried in from the Arabian Sea

The origin of the extraordinary woodlands of P. cineraria is unclear, but may be related to earlier patterns of drainage or to earlier periods of higher rainfall. The trees are no longer re-establishing from seed, Its survival is the result of regeneration from core root systems.

We crossed areas of some 25km long and a few kilometres wide with dense grooves of such acacia trees. Many small Bedouin villages and plenty of camels that hide between the trees.

Extract of : THE SOUTH-EASTERN BORDERLANDS OF RUB’ AL KHALI: paper read at the Evening Meeting of the Society on 3 December 1928 by BERTRAM THOMAS

....From Balad Bani Bu ‘Ali our immediate course lay east of south towards the twin peaks of J. Siyah, through a pleasant scattered “samr” jungle until, crossing Wadi Batha a few miles below our starting-point, we turned south into a scrub plain, Sih ar Rumth. We continued until dark, approaching high ground to the south, low limestone ridges on our left hand and to our right low sandhills thick with “ghaf.” This brought us to a salt depression beyond which we halted at a water-hole called Kabit on the edge of a thick acacia grove. This grove, which runs along a raised sandy ridge for 23 miles having north-and-south axis, is known as Wadi ‘Ubaidha, the term “wadi” being here employed not in the conventional topographical sense. To the west and north-west of it my escort avowed that sand stretched continuously to the Hajar Mountains and Wadi ‘Andam an eastern island of Rub’ al Khali, it would seem though this information would appear to conflict with the terrain to the south-west of Balad Bath Bu ‘Ali which Wellsted describes. My desire to take a more northerly route through this area was met with the reply that there was absolutely no water there.
I spent the next two days moving along the eastern edge of Wadi ‘Ubaidha, bivouacking at Haniya and Sufaij, first through “umm as sabkha” a large salt- crusted depression, now and then relieved by patches of sandy soil rich in camel thorn to which type of country it finally gives way. Two and three- quarter hours south of Kabit we passed two small hillocks presumably of basalt formation suggestive of cinder heaps with small jagged chunks strewn the neighbouring plain and another hill of the same kind when passing J. Faiya. Throughout Wadi ‘Ubaidha sweet water is found, and Janaba Badawi here breed good camels. Their living quarters are extremely primitive: an acacia thatch, horseshoe shaped and scarcely deserving the name of hut. It is placed usually under a spreading acacia, a freshwater-skins hang from a branch, basket of dates, suggestive of a rook’s nest, is suspended in the topmost branches out of reach of the camel. A woman, some young children, and a herd of young goats fill up the picture. The woman emerges veiled, not with proper “burqu’,” but with only her garment worn over her bead as a make shift, and in the absence of her man, to offer us water. Nowhere in South East Arabia did I see a camels’-hair tent. From time to time we passed a large hollow wood stack far from habitation. This is the Badu’s storehouse, called a “damus.” Here his winter supply of dates and fish are protected from camels and wild beasts. This he abandons days at a time, knowing that his neighbours will not touch it: the “damus” sacrosanct. In sandy country to the west the “damus” took the form of a hole in the sand covered with a turtle’s shell. Turtles are plentiful through out the ‘Oman coasts. Early morning starts were prevented by the routine of cleaning instruments, writing up records, and holding a sick parade, for I had equipped myself with a large supply of quinine and the simpler drugs, and the sick of every settlement met on the road came with their tales of woe.
Leaving the “ghaf” jungle where it ends at Sufaij, we struck towards the coast through scrub country......

 


Water well near our campsite

Grove of Ghaf (Prosopis Cineraria) trees, a typical view in the 'woodlands. Each grove cluster probably represent one ancient root system with sand captured between the roots building conical hills.
We did not follow Betram Thomas' route to the coast, but continued south where the woodlands give way to large sand flats with sabkha's to the east. The track along the eastern flank of the large dunes approaches the sea and the driving becomes more difficult in soft sand. The cliffs along the sea reveal underlying sand dunes, now hard cemented rock. We decided to try the beach, but with high tide and a steep gradient of the beach that did not feel right.

That's the area where we spent our second night, not entirely planned, camping in the dunes near the beach. Driving on the beach is one thing, but getting off through a ridge of soft dunes caused a lot of problems. At one stage all four cars were stuck and that decided where we were to spend the night. A lot of ropes tied together solved the problem, creating a kind of kinetic rope and with the pulling car on hard sand the cars smoothly got free. To our surprise again a nice cool night with a fresh breeze from the sea.

No sand problems the next morning, getting safely on the track. In the far distance there was the new road still being built, but going that way was of course not on.

Further southwards the track bends slightly landward to avoid large dunes ending in the sea. This is clearly the most spectacular, but also the most difficult part of the drive. We noticed Bedouins with an old Nissan having to navigate the dunes by rolling up and down the slopes accelerating to make it up to the next slope like in a large rollercoaster. We had to do the same.....


Coastal cliff of fossil sand dunes (aeolionites) below the modern dunes (pink cliffs). 

Rolling sand dunes running straight into the Arabian Sea. Spectacular views
An old truck that did not make it, completely swamped by the sand. It does make the point that getting stuck here happens to the locals as well
The area south of the Wahiba's is essentially flat, only a few metres above sea level, with large lagoons that have limited connections to the open sea. Depending on the amount of seawater that can flow into these flats the heating sun evaporates more water than can flow in, resulting in the deposition of salt. From here one can get to the Masirah ferry at Sannah, but we turned right to Hij and Mahout and from there further south to the beaches of Khaluf. 

Salt flat along the road to Sannah, all the white material at the edge of this huge flat area is pure salt. Away from the edge the salt has dissolved again and the crust is mainly gypsum with on top many shells of small snails, the last that managed to survive before it got too salty and everything died.

A little bit of digging shows that the salt is only a thin upper veneer. Large crystals of gypsum grow in the sand sand below. On the interface between the salt and the wet mud is a thin organic rich layer, strongly smelling of H2S produced by microbial life that survives in these extreme conditions.

The white beach south of Khaluf

After two nights in the desert two of our guests absolutely needed to re-stock cigarettes and we needed to refill our water supply at Hij before proceeding to Khaluf and its white beaches.


The wide flat beach south of Khaluf is great for camping and beach combing.

Guitar fish stranded on the beach, dead for sure, but still a marvelous animal to see. More like a mix of a shark and a ray and not surprising part of the family of rays. With eyes and slits high on the head it is clear that this kind of fish is a bottom feeder. We also saw a dead turtle and a balck/yellow spotted ray, sadly also dead.

Rudist Reef

A long, cool night and a lovely long morning on the beach the next day, only leaving at noon to travel further inland, avoiding the heat. Our next stop was the famous rudist 'reef' in the Huqf (this part of the track is not shown on the maps and not included in the track file that is linked to this story as this is protected area - data only provided on specific request). The journey inland has been made a lot easier with a new tarmac road crossing the Huqf area from Mahout in the east to Ghaba in the west. We have visited the area many times before (see our Dec 2001, Northern Huqf story)


The Huqf escarpment above our campsite, view to the great flat sabkha in the central Huqf area. The cliff homes a large outcrop with large rudists (bivalves that were the main reef-builders in the Cretaceous)

Circular feature at the foot of the cliff. Site of a possible meteorite crater. It certainly looks like from satellite image and that was the main reason to have a closer look. Not close enough and therefore another excuse for another future visit to crawl around.
Rudist are a group of bivalves which evolved during the Late Jurassic to Cretaceous and lived in warm, shallow oceans of low latitudes. They became extinct at the Cretaceous/Tertiary boundary. Most rudists have not much in common with 'normal' bivalves and developed bizarre, occasionally large shells. Different to other bivalves, one or both valves are uncoiled which allowed for accretion of the shell along the complete mantle margin and the construction of tubular shells.


Main rudists found at the ‘Saiwan’ location and reconstruction sketch, including corals and stromatoporids by Schuman and Steuber, 1997


Carbonate slab floating in the Precambrian Ara Salt at Qarat Kibrit
Our fear was a rather hot night. Arriving in the late afternoon it certainly was blazing hot. Richard tried to cook an egg on his car, but it would not even sizzle. Yet we were all hiding away under the sunshade until the setting sun left our camp area in a rapidly cooling shade. Indeed a cool night again that needed a sleeping bag. 

Qarat Kibrit

From the rudist area we plowed our way back the next day first to the Ghaba rest house on the Salalah highway  for a coffee. Being early there was plenty of time for another geological trip to the Qarat Kibrit Salt dome to do a bit of salt mining. Blocks of this old Salt (550 Million years) coming from several kilometers deep are great gifts because of their whapping geological story.

The six surface-piercing salt domes of Interior North Oman form prominent topographic and geological features in a flat, rocky desert environment. These salt domes, situated in the central part of the large Ghaba Salt Basin, have been known since the 1950’s.

Location: 11 km NW of the Ghaba North Field. Access: From the Qarn Alam Field gathering station follow the tarmac / graded road about 10 km to a roundabout. From there take the graded road to the NE to the outcrop. Size of outcrop: Circular outcrop with a diameter of some 800 m. Lithologies encountered in outcrop: Dark grey to black carbonates, grey dirty carbonates, high reflectivity stinkkalk, recrystallized porous carbonates with questionable dead oil, white marl, gypsum/anhydrite (white) and clear crystalline gypsum, salt (overall reddish colour), reddish siltstone. Description of outcrop: The fair size, fault-bounded, outcrop is characterised by a pronounced wall of dark platy carbonates along the western rim whereas the centre and the northern, southern and eastern rim predominantly consist of low relief salt and carbonate outcrops. The exception being two jagged salt/carbonate cliffs in the centre which have both been mined for salt. The salt is mainly comprised of banded pink/white/brick-red halite. The most central outcrop consists of salt caves on both sides of a westerly dipping platy, fetid carbonate section of some 50-60 m thickness. This could indicate a stringer origin for this type of carbonate. Red siltstones were encountered in the salt and on the south-eastern rim. On the salt cliff in the northern part of the outcrop a (porous, dirty) carbonate lens is exposed. Two relatively shallow wells have been drilled on the northern flank of the salt dome (Qarat Kibrit-1 and -2). Tilting of the Palaeozoic-Mesozoic sequence took place in Late Cretaceous times due to an active phase of diapirism. The Lower Tertiary Um-er-Rhaduma carbonates were deposited following a major phase of erosion. A Middle Tertiary phase of diapirism resulted in tilting and erosion of the Um-er-Rhadumah in the crestal area, followed by deposition of carbonates of the the Fars Group. Tilting of the Fars Group carbonates on the flanks of the current outcrop represents the (as yet) latest movements of the Qarat Kibrit diapir. (Peters et al., 2003)


Salt in the centre of Qarat Kibrit

Gerdien tells Richard where to find the best salt. In the old days this was a job for convicts....
A long drive (350km) home with a narrow escape from a careless suicidal driver. Overtaking without checking left Richard shell-shocked with a truck passing to his left and the suicidal driver to his right. Just be careful on these roads.

A plea to the drivers out there to mind for others and only overtake when they can see there is nobody coming in their direction.

Special thanks

To Emily, Gerdien, Maaike, Erica, Gregor, Rob, Rick, Jelle, Freek, Richard and Peter for their great company.

References

Brown, K., , 1992,  Prosopis cineraria woodlands of Oman: past, present and future (English). In: Prosopis species: aspects of their value, research and development; Proceedings of the Prosopis Symposium, held by CORD, University of Durham, UK, 27-31 July 1992 Dutton, R.W. (ed.) Powell, M. (ed.) Ridley, R.J. (ed.) / FAO, Rome (Italy). Plant Production and Protection Div.; Durham Univ. (United Kingdom).

PETERS, J.M., FILBRANDT, J.B., GROTZINGER, J.P., NEWALL, M.J., SHUSTER, M.W. & AL-SIYABI, H.A. 2003. Surface piercing salt domes of interior north Oman and their significance for the Ara carbonate “stringer” hydrocarbon play. GeoArabia 8, 231-270.

Thomas, B., 1928. The south-Eastern Borderlands of Rub' Al Khali: paper to the Royal Geographical Society read at the evening meeting of the Society on 3 December 1928.

 

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@ J. Schreurs October  2008