Geology of Somaliland

The older rocks pre-date the Pan-African orogeny and were affected by both igneous and metamorphic activity 840, 800 to 760 and 720 million years ago.

Major Event II, more than 700 million years ago, marked deformation, partial melting (also known as anataxis) and rocks metamorphosed up to amphibolite grade.

Granites were emplaced and the deposition of the low-grade, metasedimentary Inda Ad sequence occurred, followed by more deformation and regional heating.

The sequence of events in Somaliland in the Proterozoic correlates with the Arabian-Nubian Shield to the north, which experienced igneous activity related to subduction and witnessed the formation of marginal basins and island arcs.

The marine transgression of the Tethys Ocean flooded large parts of East Africa and Arabia and new sedimentary rock units were deposited.

Outcrops of these rock units are limited to a few coastal areas in Somaliland, but rapid faulting created offshore basins with up to two kilometers of sediments from the late Cenozoic.

[3] Of particular significance for Somaliland, rifting in the Oligocene and Miocene reactivated Mesozoic normal faults, forming the Guban Basin.

The basin is situated within a topographic high, known as the Somaliland escarpment and is filled with up to three kilometers of Late Cretaceous and Cenozoic sedimentary rocks.

In places within the basin, the Late Cretaceous Jesomma sandstone is overlain by the eroded remnants of the Eocene Taleh Anhydrite.