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A BRIEF GEOLOGIC OVERVIEW OF OMAN

Oman has been acknowledged world-wide as a geological wonderland. The current topography is strongly shaped by the geologic formations and features exposed at the surface. These structural features and stratigraphic successions in turn were shaped by tectonic forces which have been active over hundreds of millions of years and are still very active today.

There is no place in the Sultanate one can go and not stand in awe of its surface geology, the time and environments represented and those forces which created it. Possessing an arid to dry climate means there is little ground cover to obscure the landscape. This landscape contains rocks that date as far back as 800 million years. These include rocks from the earth’s mantle, from subduction zones, from lush carbonate platforms teeming with life, from vast rivers whose floods would have covered thousands of square miles. Dinosaurs walked here, mosasaurs swam in the seas here and glaciers reigned for 200 million years.

Our formal understanding of the geologic history of Oman began shortly after the earliest oil concessions were granted. It still took into the 1950s to penetrate and describe the country’s interior. Some areas, such as the Musandam Peninsula were not investigated in great detail until the early 1970s.

The stratigraphic column for Oman represents both outcrop and subsurface analyses. For Oman there are 16 major subdivisions called ‘Groups.’ The names of formations are derived for the most part from subsurface work. The groups and formations, as well as some members within formations, are age-constrained. This allows them to be correlated with events that occurred through time across the Arabian tectonic plate and major world-wide events. Because of this geological information from neighboring countries can provide insights into Oman’s geological past and its hydrocarbon potential.

Stratigraphy for the Sedimentary Section in Oman

Geochronology for the Sedimentary Section in Oman

Oman also contains several structural regions. These reflect the role global tectonism has had upon the Sultanate. Hydrocarbons have been discovered in each of the structural provinces.

Salt basins are the largest, most laterally extensive structural provinces in Oman. There are three recognized basins.

  • The Fahud Salt Basin
  • The Ghaba Salt Basin
  • The South Oman Salt Basin

These have been informally sub-divided over time. Most of the Sultanate’s oil fields are found within the salt basins.

Field also exist in the rocks underlying and adjacent to the Hawasina Thrust. This thrust system contains material from as far away as 200 kilometers from present day Oman which has been thrust over the autochthonous section. Thrust regions also exist in eastern and western Oman.

There are several broad arches and flexures found across the country. In northern Oman the largest is the Jabel Akhdar. Outcrops here expose the major reservoir formations in this part of the country. This provides a rare opportunity to move directly from outcrop to the subsurface oil fields. In eastern Oman is the Huqf High. Like the Jabel Akhdar significant reservoirs are exposed in outcrop. From the outcrops exposed in arches across the Sultanate geological concepts can be derived for many of the existing and potential reservoirs found in the blocks.

Oman Structural Features map


Last updated at 11/10/2016