Hasik

April 2009

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To Hasik through the basement granites and gneisses east of Mirbat, Dhofar, South Oman



An easy day-trip from Salalah, but there is so much more to enjoy. To quote Pinaki (2007) ".....Hasik and its coast might be the end of the road now, but there was a time when they might have been the beginning...." and it surely will be the beginning for the interested traveler......
Most visitors exploring the coast east of Salalah don't get beyond Mirbat. Yet there is so much more, not in the least because of a very different geological background. A few years ago the area beyond Mirbat would have needed a lot of time and a decent 4WD car. The tarmac now extends to beyond Hasik, with work ongoing to connect the coastal plain of Salalah to Shuwaymiyah within a couple of years, opening-up the last bit of inaccessible Oman.

Initially the road coasts inboard, away from the sea, but beyond Sadh the engineers have done an excellent job, creating a road with a 'view', cutting through hard granites and gneisses on one side and opening-up a marvelous beaches and headlands all the way up to Hasik and beyond.


Location map, showing Oman (inset) and a more detailed satellite image of the Mirbat-Hasik basement-rock area, clearly darker than the deeply incised lighter limestone of Jabal Samhan to the northwest. Note the straight scarp separating the basement in the south from the limestones in the north. Drainage patterns are dendritic towards the northwest on the Tertiary limestones of Jabal Samhan compared to straight wadi's cutting the basement rocks, draining southwest into the Arabian Sea.
How to get there:
An easy drive, all tarmac, about 200km east of Salalah.
Take the coastal road from Salalah to Mirbat and from there follow Juffa, Sadh, Hadbeen, Hasik. Check this Hasik Google Earth Track file link, which you can open in Google Earth and display in all its detail. 

A bit of Geology

From Salalah to Mirbat one drives through an essentially flat coastal plain, albeit with a few coastal terraces. This changes beyond Mirbat where the roads starts winding through what is known as the "basement rocks" of Oman. These are the oldest rocks in Oman, very recognizable on satellite images as the darker rocks to the south-southeast of the knife-sharp scarp of the younger Cretaceous and Tertiary limestones of Jabal  Samhan. Originally a flat plateau these rocks are now deeply incised by various wadis draining into the Arabian Sea. These old rocks comprise everything one expects in basement rocks: granites, gneisses, highly deformed and highly metamorphosed.

The igneous-volcanic basement rocks were jumbled together at around 800 Million years ago, but contain reworked rocks that are older than 1300 Million years. It was subsequently intruded by various phases of intrusives from 780-700 Million years.

Simplified geological map of the basement terrain between Mirbat and Hasik (above) and its corresponding Satellite image (below). The main rock units are named after the villages in the area (Sadh, Jafa, Habdin, Fusht). Simplified after the BRGM geological map of Oman.

From Mercolli et al., 2006: ".... The crystalline basement of the Salalah area (Dhofar, Sultanate of Oman) is the largest portion of Proterozoic basement of the Arabian-Nubian Shield outcropping in Oman. Its four main rock units comprise: 1) the Juffa Group consisting of metasedimentary mica-gneisses, amphibolites and few meta-ultramafic lenses. 2) the Sadh Group with two sub-units, the highly deformed and metamorphosed Banded Gneiss Complex intruded by the slightly deformed diorite and tonalite of the Mahall Complex. 3) the Tonalite Group including three large calc-alkaline plutons, the gabbroic Hasik Complex, the dioritic-tonalitic Fusht Complex and the tonalitic Hadbin Complex. 4) The Granite Group comprising different type of dykes and small bodies, i.e. the Pegmatite Complex, the Marbat Granodiorite, the Leger Granite and the basaltic to rhyolitic Shaat Dyke Swarm. The sediment sources of clastic sedimentary precursors of the Juffa Group gneisses represent the oldest rocks (>1300 Ma) recorded in the geological evolution of Oman's basement. Crustal accretion processes culminate around 800 Ma. Extensive cyclic calc-alkaline magmatism over a period of some  50 Ma (830–780 Ma), intercalated by intense deformation and recrystallisation at amphibolite facies (>815–790 Ma), built up the major lithostratigraphical units (Juffa-, Sadh-and Main Intrusive Group). The intrusion of a large amount of aplites and pegmatites forming the Pegmatite Complex took place between 770 and 750 Ma. The younger (750–700 Ma?) emplacement of the Mirbat Granodiorite, Shaat Dyke Swarm and Leger Granite mark the end of the magmatic and metamorphic activity in this area. Subsequently these units were exhumed to the surface and overlain by clastic sediments of the Marbat Formation of probable Ediacaran age (630–542 Ma) and by the Phanerozoic sedimentary sequences....."

The basement terrain east of Mirbat is special in that is cut by a series of basaltic dykes, striking overall in northwest-southeast directions. These intrusive dykes, known as the "Shaat dyke swarm" form prominent ridges that dominate the landscape and can even be seen from outer space (see Google Earth image below).

Satellite image (Google Earth) showing pervasive northwest-south-east running dykes, cutting though the basement rocks, forming prominent ridges in the landscape as shown in the inset-photograph. Cretaceous / Tertiary limestones on top of basement rocks form the ridge (Jabal Samhan) in the background of the inset photograph.

These pervasive dykes can have a thickness of several metres, and generally have a spacing of several hundred metres apart. 


Basaltic dyke-ridges (above and below) forming prominent ridges (above) and in road-cuts (right).

The dykes vary in thickness between centimetres to several metres. 

One of the many basaltic dyke-ridges that characterise the basement rocks east of Mirbat. Take a bit of time to check-out these black rocks. You may find some interesting plants, or even frankincense trees growing on their flanks. One could easily imagine these black walls to have been built by giants or jinns.  
Near Sadh the road approaches the sea and from there it tracks the rocky coast all the way to Habdeen (Habdin). Massive granite outcrops reveal a characteristic rounded weathering (bag of wool) that starts with intricate fracture patterns in the homogenous rocks. The beaches between the rock promontories essentially consist of the same granitic material, but now of course as loose 'sand'. Near Habdeen the granite (granodiorite more precisely) is of 'ornamental' quality, earmarked for mining as a decorative stone because of its nice colour and quality polish. Despite its remote location it appears that limited mining has started. 
Camels relaxing on the beach of Hadbeen, clearly enjoying the cooling waves rolling on the soft beach sands between the granite boulders. By now the basaltic dykes have disappeared and the landscape is dominated by the rounded granite outcrops.

Clouds draping the granite peak of Jabal Nuss near Habdeen

Bleached granite outcrops near Hadbeen, cut by many joints in different directions and in-between rounded by extensive coastal weathering .
North of Hasik, at Ras Al Nuss  and beyond to Hasik, the road becomes truly spectacular, cutting deep into the granites and gneisses, beautifully weathered by the hammering sea. It is like driving in the clear sea, with continuous variations in colours. One almost expects to see dolphins and turtles. We noticed big patches rippling with hundreds of fish (sardines?) flashing their backs at the surface. Keep an eye on the rocks higher-up. You will notice the flat lying Tertiary limestones that overly the basement rocks slowly approaching. Approximately halfway Hasik these reach the sea. The limestone packages define ridges tilting to the northwest, stacked as tumbled dominos one on top of another. Small wadi's flow down the flanks of the ridges and subsequently merge where the domino blocks lie on top of each other, flowing to the sea in a northeastern direction. The road widens-up just near Hasik.

Hasik is a niyabat of the Wilayat of Sad(a)h  and you are now some 200 Kilometres from Salalah.  The niyabat has an ancient ruined town and an old harbour that was used in ancient times for the export of frankincense. In Wadi Seenaq there is a khor (creek) surrounded by marine plants and shrubs that provide a refuge for nesting turtles and the migrant birds which breed in the nearby hills. Other khors and wadis include Khor Ahreez, Wadi Rabkut and Wadi Dahnat, which has the stone ruins of an ancient settlement on its banks, indicating that there was a prosperous placein earlier times.

Hasik itself, with its unique harbour, was well-known to Arab seafarers as a trading centre on the Arabian Sea, particularly for merchants trading in top quality frankincense. Hasik has a natural sheltered harbour. In earlier times traders used to meet on the edge of the town to barter their wares, which would then be loaded onto ships and transported to East Africa, Yemen and India.

The limestones overlying the old basement define the coastline beyond Hasik. The near horizontal beds are stacked on top of each other as layers of a cake, one a bit softer or harder than the other, creating overhangs and ledges. The limestone rocks easily absorb water during the rainy season, which sinks in the rocks and flows on top of impermeable clayey layers towards springs. Even in the dry season (we visited in April) there are many places where water drips from the rocks, with green curtains hanging from above, feeding lines of plants below, encrusted with lime, creating travertine draperies.

Popular picnic spots during the rainy season include the cascading waterfalls of Natif and the overflowing pools fed by the springs of Shairookh and Ain 'Aidhah. The new road leads you along these places, with resting areas, parking places and toilets being built (like it or not, it comes with the road).

The precious abalone breed in offshore waters. Some 45 tonnes of this rare and expensive shellfish with a high nutritive value are caught every year during the diving season' (see Oman Today, 2007).

The seabed near Hasik is sandy and rich in fish. We noticed at least a dozen turtles feeding within reach of the shore, continuously diving and surfacing on their quest for food. 


A layer cake of Tertiary limestones in a sheer vertical cliff-face next to the sea beyond Hasik

Stalactites  forming draperies, dripping and sometimes even showering the plants below. Some of the overhangs form natural caves. Water, caves and seafood are the ideal combination for people and not surprising one finds pieces of flint tools and the remains of shells and turtles all over these places

A popular place for turtles. We saw some dozen of them diving in the green waves, regularly sticking-out their bold heads before disappearing below again.

Draperies or is it more like natural set of organ pipes? Spectacular travertine formations
The road currently ends some 8 km's beyond Hasik where wadi Dahanat reaches the sea. The military post at the end is built at the edge of Bedouin-type graves of small platforms surrounded by heavy stones and filled by pebbles. The graves surround a site marked for helicopter landing. Eerie? 

In the future the road will connect to Shuwaymiyah (it is planned for completion in 2011). From Hasik, the blacktop will run north along the shoreline for about eight kilometres (the current end of the road) before veering inland through the rocky hills of Jabal Samhan. After traversing rugged terrain for over 60 kilometres, the road would descends to the coastal plains of Shuwaymiyah where a final roughly 20-kilometre stretch will run about a kilometre inland from the shoreline.


The wadis between Mirbat and Hasik also grow frankincense. A small scratch and the white resin oozes out with an unmistakable smell

Big herds of hundreds of goat, short-haired (very different from the long haired ones in Jabal Al Akhdar).

The end of the road? The beginning of much more in the past as Pinaki (2007) remarks. The beginning of a new road in the making. Difficult to imagine that only a few years ago the only easy way to get here was by boat. Still a quiet area because of its distance from Salalah, but very worthwhile discovering. In one day we missed so many things such as the Tomb of the Prophet Saleh, reportedly located in a narrow valley of Anhoor, between Hasik and Hadbeen near Ra's Nus. The tomb is 8,80 metres long and 1,5 metres high. What about the ancient ruins labeled on the map at Khor Samhal. Many reasons to go back......

References

Hauser, A., Zurbriggen, R., 1992. Geology of the crystalline basement of the Hadbin area (Salalah area, Dhofar, Sultanate of Oman). MSc-thesis, MPI, University of Berne

Oman Today, 2007, Desert beaches of Hadbin. Oman Today, 2007, volume 7.

Pinaki, Chakravarty, 2007. Hasik: one month of Abalone. Oman Today, 2007, volume 12.

Mercolli,I. ,Briner A.P., Frei, R., Schönberg, R., Nägler, T.F., Kramers, J. and Peters, T., 2006. Lithostratigraphy and geochronology of the Neoproterozoic crystalline basement of Salalah, Dhofar, Sultanate of Oman. Precambrian Research, Vol. 145, Issues 3-4, p. 182-206.

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@ J. Schreurs April 2009