Lithostratigraphy, deformation history, and tectonic evolution of the basement rocks, Republic of Yemen: An overview

Basement rocks of presumed Precambrian age, in Yemen Republic (105,000 km²), are exposed in the northwestern and southeastern parts of the country. The basement rocks of southern Saudi Arabia and northern parts of Yemen are almost continuous and similar in the lithostratigraphic succession. In spite of the presence of such common basic characteristics for each, there are slight differences of local structural framework and major tectonic events. The structural complexity, great variety of rock units and types, multi-intrusive environments, and multiplicity of metamorphic events in the study basement rocks make the main target of lithostratigraphic analyses, in particular, daunting in the southern Arabian Shield. As reported here, accepting that the southern shield consists of five terranes and suture zones requires a limitation of such tectonic modifications. This led to the renaming of certain formations and groups and the revision of the lithostratigraphic successions for some regions. As a result, new lithostratigraphic relationships and names as well as tectonic events are proposed. Based on field and space image data, the basement rocks in Yemen exhibit at least six major phases of deformation (D1 to D6) including intensive brittle and ductile deformations that trend NW-SE and NNE-SSW (in major). Neoarchean rocks are well developed and restricted in the southeastern exposures (Al Bayda, Al Mahfid, and Al Mukalla terranes), whereas the final Pan-African cratonization of several rock units is widespread on all terranes, in which the major tectonic events and deformation history were concentrated during pre-Pan-African and early to late Pan-African orogenies. A correlation and evolution of the Precambrian rocks in Saudi Arabia and Egypt are taken into consideration.