LESSONS ON THE ROAD: Group leader and senior geologist Saeed al-Kuwari explaining the significance of each site through descriptive posters. Photo by G John
By G John
It was a field day for the members of Qatar Society of Petroleum Engineers (QSPE), their families and guests, as they set out to explore the Qatar Arch – a cross-section of the peninsula from Doha to the western coastline of Dukhan and Umm Bab. A stretch of approximately 120km, the Qatar Arch, as the name suggests, is a surface elevation of land mass, replete with geological characteristics unique to the country and region.
Organised by Qatar Geological Society (QGS), the trip was led by Saeed al-Kuwari, senior geologist at Qatar Occidental Petroleum Ltd and member of QSPE.
Divided into six stops across the Arch, the trip began from Hyatt Plaza, which was the designated meeting point for over 20 SUVs that had assembled in the early hours of Friday morning. After a briefing of road safety instructions, the convoy began to roll for the first stop of Mekaines, a 20-minute ride across the Salwa Road.
Says al-Kuwari: “This is an annual trip for QSPE members and their families. The idea is to explore the surface geology of the Qatar Arch, which hosts significant hydrocarbon traps and defines the peninsula of Qatar itself.”
The first stop is an inspection of karst topography and expression in Umm Al Shabrum area. Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. This creates land forms such as shafts, tunnels, caves, and sinkholes. Groundwater seeps into and through these land forms. The result is a landscape fragile, and vulnerable to erosion.
For a layman, geological terms like ‘karst’ and ‘dolomite’ may sound like Greek or Latin, but al-Kuwari, who is a veteran of several trips in the past, had planned on-site presentations in the form of illustrations and descriptive posters to drive home the point. More than the technicalities, which were the topic of discussion among the geologists and engineers present in the group, the idea was to learn more about the surroundings we live in.
Moving on, the second stop was a karst cave in the same area that is also a major tourist attraction in Qatar. The cave is a gigantic room, extending downward about 50-60m, formed by the collapse of carbonate material. This happens when downward percolating rain water dissolves carbonate rock and causes collapse of the overlying rock and large depressions form over fracture or fault zones which drains the water away. The cave walls are composed of upper Dammam dolomite and limestone unit and the lower Dammam laminated shaly.
Traversing through vast swathes of desert on the western side of the Arch, camels could be spotted at regular intervals. Many of them seemed to be in the wild and unrestrained, though there were occasional patches of human habitation. This locality is also known for camping in the winter months.
The convoy was now headed to the chalk reservoir and Dam Formation of the Al Kharrara member made up of limestone, marl and claystone. Further ahead, was the gypsum bed in the Al Nakhash member of the Dam Formation. According to al-Kuwari, “this stop was meant for the observation of a gypsum dissolution ‘syncline’, tracing the lateral extent of the gypsum layer exhibits and discontinuous nature of gypsum beds in the Upper Dam Formation.” This stop was of particular interest for the children in the group who were busy collecting stones of various hues and textures.
By now it was lunch time and the fresh water Pliocene river deposits provided the ideal location. The fresh water deposit dates back to 180,000 years and comprises sand and rocks of different colours and sizes from the Arabian peninsula. Says al-Kuwari: “The river bed was so thick that its erosion resulted in the formation of sand dunes in southern Qatar.”
It was time to bid adieu. There was one last stop at Umm Bab, on the far western side of the Qatar Arch. Here the main attraction was to look for shark teeth in a clay bed, which is 60mn years old and was once part of the sea. And as per records, the place where we stood was a favourite hunting ground of the sharks. Despite some intense search and prodding by al-Kuwari with pictures of shark tooth, none of the group members were successful in finding one.
