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The Tethyan region is a major petroleum province. The paleogeographic position and tectonic history is a major control on sedimentation across the region, and this has influenced the sequestration of hydrocarbons in the region. The North African-Arabian plate evolved along the Tethyan margins (Proto-Tethys, Paleo-Tethys, Neo-Tethys) from Pre-Cambrian to Recent.  

In the Tethys region, the evolution of North Africa and the Arabian Plates are intimately involved with the occurrence of hydrocarbons in both regions. In the Early Paleozoic, paleogeography was characterized by the breakup of Rodinia and by the re-arrangement of the major continental plates in the Pangea supercontinent. During the assemblage of Pangea, a major role was played by the transformation from Pangea B to Pangea A during Permian time by means of dextral motion of Laurasia relative to Gondwana, which changed the relative position of the Paleozoic and Mesozoic domains facing the east-west oriented Tethys Gulf (Muttoni et al., 2009a, b).

 

Since late Paleozoic time, the southern margin of the Tethys was affected by the time-transgressive opening of the Neo-Tethys, which gave origin to a complex mosaic of peri-Gondwanan terranes. They gradually collided, during Mesozoic and Cenozoic times, with the northern margin of the Tethys, as the oceanic lithosphere of the Paleo-Tethys Ocean was subducted below Laurasia. Collisions were distributed irregularly along the northern margin of the Tethys. The spreading of the Neo-Tethys balanced the subduction of the oceanic lithosphere along the northern margin of the Paleo-Tethys, preserving the Tethys Ocean until the beginning of Cenozoic time. The subduction of the Paleo-Tethys led to the accretion of microplates that today characterize the Middle East outside of Arabia. Accretion started in Triassic time with the Cimmerian orogeny and persisted up to today, with the collision of Arabia along the Zagros suture. The present day relationships among orogenic belts are further complicated by the presence of important strike-slip movements, which accommodated the different convergence rates among plates, from the Alps to the Himalayas.

 

The Mesozoic and Cenozoic evolution of the Tethys Oceans was also affected by the plate reorganizations caused by the breakup of Pangea. The opening of the Atlantic Ocean further complicated the geodynamic settings of the Laurasian and Gondwanan margins due to the changes in stress fields during different stages that characterized the breakup of Pangea. In particular, the movement and rotation of Africa, controlled by the opening of the central and southern Atlantic oceans, heavily controlled the relative motions among the numerous plates (which suffered alternatively both extensional and compressional tectonic regimes) in the Tethys. The present-day setting of south Mediterranean and Middle East regions is therefore the result of the global reorganization derived from the closure of the Tethys Ocean(s) and the time-transgressive opening of the Atlantic Ocean.

 

Different and sometimes incompatible reconstructions exist for some intervals and, as data can be either contradictory and/or scarce, it is frequently a matter of interpretation which of several alternative reconstructions should be favored, and which should be discarded. For these reasons, paleogeographic maps should always be viewed as a work in progress, and should be continually revised and reconsidered in the light of new data. Also, differences mainly increase with the detail of the maps. Therefore, the maps presented here constitute just one of the possible solutions and do not aim to represent definitive paleogeographic reconstructions. In our opinion, these maps generally honor the available data, which mainly summarize long, complex, and multidisciplinary studies from regions that are not always easily accessible (sometimes for political reasons).

 

The distribution of giant oil and gas fields in North Africa, Arabia, and the Middle East is the result of the interplay between the paleogeography of oceanic and continental areas, which favored the creation of source rocks, and the geodynamic evolution of Pangea and the Tethys Oceans during the Phanerozoic. There is a range of different basin types, with a dominance of rift and sag basins, passive margin basins, and collision-related basins, often evolving from one type to another. The interplay between sedimentation and tectonics controlled both basin development and post-depositional deformation, favoring the creation of a large number of structural and stratigraphic traps that store a significant percentage of the world’s oil and gas reserves.

==Paleogeographic reconstructions==

==Paleogeographic reconstructions==

Paleogeographic maps have been reconstructed for selected time intervals: Cambrian, Late Ordovician, Early Devonian, Early Permian, Permian-Triassic boundary, Norian, Callovian, Aptian, Cretaceous-Cenozoic boundary, and Late Eocene. For each time interval both the general picture of the major plate tectonic configuration and a detail of the paleogeography and paleoenvironment of North Africa to the Middle East are presented. On these maps, the major paleoenvironmental settings (from continental to shallow marine and deep ocean) are shown for the area stretching from North Africa to Afghanistan in all the selected time slices. Besides the major tectonic events, the global climate evolution and their interplay are discussed, which in some cases led to significant biotic turnovers or even to mass extinctions (e.g., Late Ordovician, Permian-Triassic boundary, Cretaceous-Cenozoic boundary). Paleogeographic maps have been compiled from literature, selecting those based on sound paleomagnetic/paleobiogeographic data. Each map is accompanied by the description of the major tectonic events that characterized the considered time interval. When contrasting paleogeographic reconstructions were available, their differences have been discussed. In general, major differences concern the interpretation of the setting and positioning of the microplates and terranes between the major continental plates.  

Paleogeographic maps have been reconstructed for selected time intervals: Cambrian, Late Ordovician, Early Devonian, Early Permian, Permian-Triassic boundary, Norian, Callovian, Aptian, Cretaceous-Cenozoic boundary, and Late Eocene. For each time interval both the general picture of the major plate tectonic configuration and a detail of the paleogeography and paleoenvironment of North Africa to the Middle East are presented. On these maps, the major paleoenvironmental settings (from continental to shallow marine and deep ocean) are shown for the area stretching from North Africa to Afghanistan in all the selected time slices. Besides the major tectonic events, the global climate evolution and their interplay are discussed, which in some cases led to significant biotic turnovers or even to mass extinctions (e.g., Late Ordovician, Permian-Triassic boundary, Cretaceous-Cenozoic boundary). Paleogeographic maps have been compiled from literature, selecting those based on sound paleomagnetic/paleobiogeographic data. Each map is accompanied by the description of the major tectonic events that characterized the considered time interval. When contrasting paleogeographic reconstructions were available, their differences have been discussed. In general, major differences concern the interpretation of the setting and positioning of the microplates and terranes between the major continental plates.  

In the Arabian peninsula, Mann et al. (2003) identified three basin types preserving giant fields: continent–continent collision for the elongate fields along the Zagros Mountain front; passive margin basins of the southern shore of the Neo-Tethys (central Arabian peninsula and Persian Gulf area); and continental rifts with overlying sag basins on the eastern Arabian Peninsula. Source rocks and reservoirs are present at different stratigraphic levels, reflecting a complex interaction of depositional and tectonics events (Fox and Ahlbrandt, 2002; Pollastro, 2003).

In the Arabian peninsula, Mann et al. (2003) identified three basin types preserving giant fields: continent–continent collision for the elongate fields along the Zagros Mountain front; passive margin basins of the southern shore of the Neo-Tethys (central Arabian peninsula and Persian Gulf area); and continental rifts with overlying sag basins on the eastern Arabian Peninsula. Source rocks and reservoirs are present at different stratigraphic levels, reflecting a complex interaction of depositional and tectonics events (Fox and Ahlbrandt, 2002; Pollastro, 2003).

==See also==

==See also==