The Oman Exotics: a key to the understanding of the Neotethyan geodynamic evolution

Pillevuit, Alain; Marcoux, Jean; Stampfli, Gérard M.; Baud, Aymon

doi:10.1080/09853111.1997.11105303

Cited by 99 publications

(63 citation statements)

References 12 publications

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“…During the Middle to Late Triassic further extension occurred in the northern and eastern part of the Arabian passive margin. The occurrence of alkali basalts in Oman, Turkey and Zagros in this time span is good evidence for this extensional regime [59]. A discontinuous oceanic-type ridge developed parallel to the Neo-Tethys in the Arabian passive margin in the Middle to Late Jurassic time.…”

Section: Discussionsupporting

confidence: 53%

Geochemistry and geodynamics of the Mawat mafic complex in the Zagros Suture zone, northeast Iraq

Azizi¹,

Hadi

Asahara

et al. 2013

Open Geosciences

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Abstract:The Iraqi Zagros Orogenic Belt includes two separate ophiolite belts, which extend along a northwest-southeast trend near the Iranian border. The outer belt shows ophiolite sequences and originated in the oceanic ridge or supra-subduction zone. The inner belt includes the Mawat complex, which is parallel to the outer belt and is separated by the Biston Avoraman block. The Mawat complex with zoning structures includes sedimentary rocks with mafic interbedded lava and tuff, and thick mafic and ultramafic rocks. This complex does not show a typical ophiolite sequences such as those in Penjween and Bulfat. The Mawat complex shows evidence of dynamic deformation during the Late Cretaceous. Geochemical data suggest that basic rocks have high MgO and are significantly depleted in LREE relative to HREE. In addition they show positive ε N values (+5 to+8) and low 87Sr/86Sr ratios. The occurrence of some OIB type rocks, high Mg basaltic rocks and some intermediate compositions between these two indicate the evolution of the Mawat complex from primary and depleted source mantle. The absence of a typical ophiolite sequence and the presence of good compatibility of the source magma with magma extracted from the mantle plume suggests that a mantle plume from the D layer is more consistent as the source of this complex than the oceanic ridge or supra-subduction zone settings. Based on our proposed model the Mawat basin represents an extensional basin formed during the Late Paleozoic to younger along the Arabian passive margin oriented parallel to the Neo-Tethys oceanic ridge or spreading center. The Mawat extensional basin formed without creation of new oceanic basement. During the extension, huge volumes of mafic lava were intruded into this basin. This basin was squeezed between the Arabian Plate and Biston Avoraman block during the Late Cretaceous.

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Section: Discussionsupporting

confidence: 53%

Geochemistry and geodynamics of the Mawat mafic complex in the Zagros Suture zone, northeast Iraq

Azizi¹,

Hadi

Asahara

et al. 2013

Open Geosciences

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“…With time, the northern Oman rift system evolved in the Neo-Tethys, and the eastern Oman rift system in part of the early Indian Ocean (e.g. Stampfli, Marcoux & Baud, 1991;Le Métour et al 1995;Pillevuit, 1993;Pillevuit et al 1997;Belushi, Glennie & Williams, 1996).…”

Section: Geodynamic Evolution 3a Late Carboniferous To Late Cretacementioning

confidence: 99%

“…Some pillow basalts are found at the base of the Al Jil Formation. In the proximal domains of the Batain basin, Al Jil platforms topped fault-block highs, while further seawards, coeval carbonate platforms probably grew on seamounts (Pillevuit, 1993;Immenhauser et al 1998), similar to the 'exotics' in the eastern Hamrat Duru basin (Stampfli, Marcoux & Baud, 1991;Le Métour et al 1995;Pillevuit et al 1997). Exposures of the Al Jil Formation are commonly found in stratigraphic contact near or atop 8 A. I M M E N H AU S E R A N D OT H E R S Figure 5.…”

Section: Geodynamic Evolution 3a Late Carboniferous To Late Cretacementioning

confidence: 99%

Late Palaeozoic to Neogene geodynamic evolution of the northeastern Oman margin

et al. 2000

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When the highlands of Arabia were still covered with an ice shield in the latest Carboniferous/Early Permian period, separation of Gondwana started. This led to the creation of the Batain basin (part of the early Indian Ocean), off the northeastern margin of Oman. The rifting reactivated an Infra-Cambrian rift shoulder along the northeastern Oman margin and detritus from this high was shed into the interior Oman basin. Whereas carbonate platform deposits became widespread along the margin of the Neo-Tethys (northern rim of Oman), drifting and oceanization of the Batain basin started only in Late Jurassic/Early Cretaceous time. Extensional tectonics was followed in the Late Cretaceous by contraction caused by the northward drift of Greater India and Afro-Arabia. This resulted in the collision of Afro-Arabia with an intra-oceanic trench and obduction of the Semail ophiolite and the Hawasina nappes south to southwestward onto the northern Oman margin ∼80 m.y. ago. During the middle Cretaceous, the oceanic lithosphere (including the future eastern ophiolites of Oman) drifted northwards as part of the Indian plate. At the Cretaceous–Palaeogene transition (∼65 Ma), oblique convergence between Greater India and Afro-Arabia caused fragments of the early Indian Ocean to be thrust onto the Batain basin. Subsequently, the Lower Permian to uppermost Maastrichtian sediments and volcanic rocks of the Batain basin, along with fragments of Indian Ocean floor (eastern ophiolites), were obducted northwestward onto the northeastern margin of Oman. Palaeogene neo-autochtonous sedimentary rocks subsequently covered the nappe pile. Tertiary extensional tectonics related to Red Sea rifting in the Late Eocene was followed by Miocene shortening, associated with the collision of Arabia and Eurasia and the formation of the Oman Mountains.

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“…They are considered to have originated either from the Neotethys oceanic domain or from its rifted continental margins. The common occurrence of Permian pillowed basaltic flows at the base of the Hawasina Nappes has often been taken as evidence for oceanic crust formation [Glennie et al, 1974;Blendinger et al, 1990;Stampfli et al, 1991;Pillevuit et al, 1992Pillevuit et al, , 1997, and thus these basalts are considered direct witnesses of the middle Permian Neotethys seafloor [Stampfli and Pillevuit, 1993]. Alternatively, it has been proposed that the material of the Hawasina Nappes formed on the continental crust of the Arabian Platform during rifting and/or breakup processes [Lippard et al, 1986;Béchen-nec, 1988;Béchennec et al, 1988Béchennec et al, , 1990Béchennec et al, , 1991.…”

Section: Introductionmentioning

confidence: 99%

Middle Permian plume‐related magmatism of the Hawasina Nappes and the Arabian Platform: Implications on the evolution of the Neotethyan margin in Oman

et al. 2003

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Permian pillow basalts are commonly found in Oman either at the base of the Hawasina Nappes or within the Arabian Platform successions exposed in the Saih Hatat tectonic window. There is an ongoing debate on whether these lavas include normal mid‐oceanic ridge basalts (NMORB) witnessing the Permian opening of the Neotethys or if they are plume‐related magmas that are emplaced either on the Arabian Platform or on its thinned continental margin. We sampled these lavas from several paleontologically dated middle Permian sites. Four of them (Buday'ah, Rustaq, Al Ajal, and Wadi Wasit) are located within the Hawasina Nappes and are exposed as thrust slices overlain by the Samail Nappe, and one (Wadi Aday) is within the Arabian Platform units and is exposed in the Saih Hatat window. These lavas are associated with marine sediments deposited in environments ranging from proximal (Saih Hatat, Wadi Wasit, and base of the thrust pile of Al Ajal) to distal (Buday'ah, Rustaq, and top of the Al Ajal pile) with respect to the Arabian Platform. Major and trace element features of the basalts allow two groups to be recognized. Enriched high‐Ti basalts similar to alkali basalts from intracontinental traps, rifted continental zones, and oceanic islands are exposed in Wadi Aday, Wadi Wasit, and at the structural base of the Al Ajal pile. Moderately enriched to slightly depleted low‐Ti tholeiitic basalt magmas resembling the low‐Ti flood basalts and those from seaward dipping reflector sequences are represented in Wadi Al Hulw in Saih Hatat, Buday'ah, Rustaq, and at the top of the Al Ajal thrust pile. Both groups show distinct plume‐related trace element signatures, and they do not include typical NMORB. Although emplaced in shallow to deep submarine environments, these basalts provide no direct evidence for a Neotethyan seafloor‐spreading event in the Hawasina Basin. Instead, they were likely erupted through the crust of the already rifted and drowned Arabian continental margin. Thus, despite their characteristic plume‐related geochemical signatures, the middle Permian basalts from Oman were not likely emplaced during the evolution of a typical volcanic rifted margin. We suggest that they originated from a mantle plume which ascended beneath the Arabian passive margin well after the initiation of seafloor spreading of the Neotethys.

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The Oman Exotics: a key to the understanding of the Neotethyan geodynamic evolution

Cited by 99 publications

References 12 publications

Geochemistry and geodynamics of the Mawat mafic complex in the Zagros Suture zone, northeast Iraq

Geochemistry and geodynamics of the Mawat mafic complex in the Zagros Suture zone, northeast Iraq

Late Palaeozoic to Neogene geodynamic evolution of the northeastern Oman margin

Middle Permian plume‐related magmatism of the Hawasina Nappes and the Arabian Platform: Implications on the evolution of the Neotethyan margin in Oman

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