Structural Geology of Afar Region (non-technical)

Structural Geology of the Afar Region

The movements of the Nubian, Arabian and Somalian plates over the past 30 million years or so have created a series of different landscapes across the Afar region each with their own distinct style Figure 1. These are:

The Afar Depression

Northern Afar Rift
Dabbahu Magmatic Segment
East-Central Afar Rift
Southern Afar Rift

Ethiopian and Somalian plateaux

Danakil and Ali-Sabieh Blocks

Southern Red Sea and Gulf of Aden

Main Ethiopian Rift (MER)

Explanation of geological terms used in the following pages:

Fault – a break or fracture in the rock which allows the rocks on one side to move relative to the other.
Rift – a region of low-lying ground (often below sea level) formed as the Earth’s crust is pulled apart as the plates move away from each other. As the crust continues to be pulled apart volcanism along the centre of the rift creates new crust to fill the gap. The Afar Depression is just reaching this stage. Where fully developed a new ocean is formed (e.g. the Red Sea) with new crust being erupted along a mid-ocean ridge.
Basin/graben – a low-lying area between faults created as the faults have moved.
Horst – an area of high ground between faults created as the faults have moved.
Fault block – an area between faults that has been tilted as the faults have moved.

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