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Modern Depositional Environments in Coastal Abu Dhabi, UAE

Ravindra Kumar
Centre of Advanced Study in Geology, Panjab University, Chandigarh

Modern sedimentary environments of the coastal islands and inland plains (‘Sabkhas’) in the coastal region of Abu Dhabi (United Arab Emirates) present an ideal example of deposition of sediments of a potential petroleum system. Basin floor of the southern part of the Arabian Gulf off the coast of Abu Dhabi slopes gently northward away from the tectonically stable Arabian Craton. Sea level in this region during the Late Pleistocene is reported to have been about 120 m below the present day sea level. Deposition of the unconsolidated sediments of the coastal region during Holocene is considered as the product of post glacial, marine transgression that reached to its acme about 5 Ka years ago. Since this time, the region has been under arid climate that has influenced the contemporary deposition of sediments both, on supra-tidal coastal plains and off shore in the shallow sea and lagoons of Abu Dhabi.
Surface currents that are generated by ‘Shamal’ winds from the north and northwest lead to periodic flooding of the coastal region and deposition of sediments of evaporate facies. Inter-tidal region is the site of deposition of algal mats in proximity with the bars of silt and sand grade sediments of lagoonal and deltaic facies. The biogenic sediments and sediments adjoining bar facies together provide an ideal combination of source and carrier beds for generation and primary migration of hydrocarbons. Islands off the coast of Abu Dhabi are the sites of reef building and deposition of carbonate sediments, oolitic sands and shelly fragments of marine organisms. These sediments of shallow seas of predominantly carbonate facies are ideal for reservoir rocks of the petroleum system.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery