MAPPING THE ARABIAN PLATE LITHOSPHERE

The formation of present day Arabia is the result of complex tectonic events, which took place in different times in the geologic history of the Arabian plate. These events varied between compressional and extensional events since the Precambrian times.

Terrane accretion in the Precambrian period is responsible for the build up of the Arabian shield that is partly outcropping in central Saudi Arabia, Yemen and Oman. This event was followed by two extensional events during the periods Late Devonian-Mid Permian and Mid Permian-Late Cretaceous. The latter two events led to the formation of the northeast Arabian margin and the neo-Tethyan Ocean. Closure of the neo-Tethyan ocean began in the Late Cretaceous and continued until present time continent-continent collision. The Middle Cenozoic, Red sea and Gulf of Aden opening represent the latest extensional event that led to complete separation of an Arabia plate from Africa.

Understanding the lithospheric structure and evolution of the Arabian plate cannot be based solely on basement outcrops, but would require the congregation of the accumulated geological and geophysical data on Arabia plate proper and it’s surrounding.

In this study we analyze new Pn tomography models of Arabia and surrounding in the context of newly published geophysical data that includes gravity, Moho depths, and seismic anisotropy of Arabia plate.

The collective analysis and interpretation of different geophysical and geological data sets showed considerable lateral variation of lithospheric structure and rheology of the Arabian plate. This variation cannot be attributed solely to temperature variation, but could also be due lithologic (compositional) variation. These variations may represent unstable lithospheric mantle or may represnt contiguous lithospheric bodies that make up the (proto) Arabia lithosphere.