The late Paleozoic to Cainozoic intraplate deformation in North Arabia: a responce to plate boundary-forces

Abstract

Several stages of intraplate deformation are dis- tinguished in North Arabia from the Late Paleozoic to Cain- ozoic. The major rifting episodes occured in the Late Carboniferous-Permian, Middle-Late Triassic and at the end of the Early Cretaceous. None of them shows clear connec- tion with plume activity. The first event correlates with the rifting of several microcontinents from the Gondwana pas- sive margin and the origin of the Neotethyan spreading cen- ter. It is speculated that it happend when the Paleotethyan ridge was subducted and the slab-pull was directly transmit- ted from the active margin to Gondwana. Triassic rifting in North Arabia (probably 2-stage) is related to rifting and transition to spreading in Mesogea. Extension ceased on the Gondwana margin when new spreading axes were formed in Neotethys and Mesogea in the Permian and Late Triassic (?) respectively. Early Cretaceous rifting coincided with forma- tion of the south-facing Peri-Arabian trench system. Again the slab pull was a possible source of extension. Collision of the Arabian passive margin with the trench system and im- mature island arcs culminated in ophiolite obduction in the Campanian-Early Maastrichtian. This event correlates with the 1st phase of inversion in the North Arabian rift basins and in North Sinai (formation of the Syrian arc). Later stages of inversion correlate with Africa-Eurasia and Arabia-Eurasia collision. To explain simultaneous shortening in the colli- sion zone, compression in the North Arabian rift basins and rifting in the Red Sea and Gulf of Aden in the Oligocene to Pliocene, a numeric model by L. Lobkovsky (1988) is used. According to it, the mantle lithosphere is detached from the crust and continues to subduct through the time of collision. The slab pull creates extension in the lithospheric mantle and rifting along pre-existing "weak zones" (Red Sea), while compression is transmitted at the crustal level to cause in- version of the intraplate basins. It appears that the slab pull is a major force behind all intraplate deformation in North Arabia.