Geological Society, London, Special Publications, 1996
... 1984, De Wet et al. 1989). ... 1994. Insert corresponds to the Paliouri area. emplaced in the... more ... 1984, De Wet et al. 1989). ... 1994. Insert corresponds to the Paliouri area. emplaced in the internal Circum-Rhodope zone and the juxtaposed Serbo-Macedonian zone, immediately to the east of the Chalkidiki ophio-lites (Kondopoulou & Westpha11986; De Wet et al. 1989). ...
Geological Society, London, Special Publications, 2008
... Lahssen Baidder 1 , Youssef Raddi 2 , Mohamed Tahiri 2 & André Michard 3 ... Bouabdelli, ... more ... Lahssen Baidder 1 , Youssef Raddi 2 , Mohamed Tahiri 2 & André Michard 3 ... Bouabdelli, M. & Piqué, A. 1996. Du bassin sur décrochement au bassin d'avant-pays: dynamique du bassin d'AzrouKhenifra (Maroc hercynien central). ...
The continental material of the Saih Hatat window has been affected by a Late Cretaceous, obducti... more The continental material of the Saih Hatat window has been affected by a Late Cretaceous, obduction-related, HP-LT metamorphism below the Oman ophiolite. A high-rate exhumation process is witnessed by the Maastrichtian-Palaeocene onlap onto the blueschist-facies rocks. Drastic metamorphic omissions are documented between the lowest, eclogitic units and the overlying, blueschist-facies ones. Widespread late-metamorphic shear structures point to a top-to-the-NNE detachment, in opposition to the sense of the Late Cretaceous obduction. The inversion of the shearing sense occurred under similar, low temperature conditions in both the blueschist and eclogite-facies units. Admitting that these HP-LT metamorphic rocks formed progressively at various depth in the subducting Arabian margin, a two-stage extensional mechanism of exhumation is suggested: (i) early uplift of the eclogitic rocks up to the blueschists depth by ductile thinning or squeezing of a ‘blind extensional allochthon'; (ii) exhumation of the whole HP-LT metamorphic core complex by inversion of the obduction sole-thrust and isostatic rebound of the lower plate.
Ductile deformation in high-pressure (P</em>)-low temperature (T</em>) conditions due to the west... more Ductile deformation in high-pressure (P</em>)-low temperature (T</em>) conditions due to the westward thrusting of oceanic material onto a continental basement in alpine Corsica is overprinted by a late deformation event with a reverse shear sense (eastward) that took place in less severe P-T</em> conditions. We show that the late deformation can be linked to extension during rifting and spreading of the Liguro Provençal basin from late Oligocene to late-middle Miocene time. Major compressive thrust contacts were reactivated as ductile normal faults and, in some units, only a penetrative eastward shear can be observed. This extension following the thickening of the crust brought tectonic units which underwent very different P- T</em> conditions during the earlier stage into close contact. The Balagne nappe, which shows neither significant ductile deformation nor metamorphism, directly overlies the high-P</em> units. The extensional deformation is distributed through the entire thickness of the nappe stack but is more important along the major thrust contacts, which localize the strain. The geometry of the crustal extension is controlled by that of the early compressive thrusts. The latest structures are east-dipping brittle normal faults which bound the early to middle Miocene Saint Florent half graben.
Geological Society, London, Special Publications, 1996
... The palaeomagnetic study demonstrates that the Ronda massifs registered a magneticfield rever... more ... The palaeomagnetic study demonstrates that the Ronda massifs registered a magneticfield reversal during their progressive cooling. The change from reverse to normal field was fol-lowed by a 46 + 8 clockwise rotation of the massifs. ...
In Oman, the convergence between Arabia and Eurasia resulted in the Late Cretaceous overthrustin... more In Oman, the convergence between Arabia and Eurasia resulted in the Late Cretaceous overthrusting of oceanic crust and mantle lithosphere onto the Arabian continental margin. During this compressional event, a part of the continental plate was subducted to a depth of more than 60 km (0.5 GPa, 250–350 °C to more than 2.0 GPa, 550 °C) resulting in progressive metamorphism of the continental margin sediments, well exposed in the Saih Hatat tectonic window, northeastern Oman Mountains. We attempt to constrain the possibility of one continuous history of extension (starting along the east Arabian continental margin in the Permian) that was followed by one continuous history of convergence starting at 90 Ma near a dead oceanic ridge. This compression resulted in the observed progressive metamorphism by ophiolite overthrusting onto the continental margin. Constraining arguments are the palaeogeographic setting before ophiolite obduction of the As Sifah units and the Hawasina Complex near Ghurba. Detrital chromites in the Triassic–Cretaceous metasediments of the Hawasina Complex are compared with magmatic Semail chromites, and the whole-rock chemistry of these metasediments and associated metabasites are investigated. In contrast to former hypotheses, differences in the chemical composition between detrital and magmatic chromites, and the probable origin of all detrital chromites in the Hawasina Basin from Permian age oceanic rocks, suggest that the high-pressure metamorphic sediments of As Sifah can be considered as part of the basal deposits of the Hawasina Basin.
Geological Society, London, Special Publications, 1996
... 1984, De Wet et al. 1989). ... 1994. Insert corresponds to the Paliouri area. emplaced in the... more ... 1984, De Wet et al. 1989). ... 1994. Insert corresponds to the Paliouri area. emplaced in the internal Circum-Rhodope zone and the juxtaposed Serbo-Macedonian zone, immediately to the east of the Chalkidiki ophio-lites (Kondopoulou & Westpha11986; De Wet et al. 1989). ...
Geological Society, London, Special Publications, 2008
... Lahssen Baidder 1 , Youssef Raddi 2 , Mohamed Tahiri 2 & André Michard 3 ... Bouabdelli, ... more ... Lahssen Baidder 1 , Youssef Raddi 2 , Mohamed Tahiri 2 & André Michard 3 ... Bouabdelli, M. & Piqué, A. 1996. Du bassin sur décrochement au bassin d'avant-pays: dynamique du bassin d'AzrouKhenifra (Maroc hercynien central). ...
The continental material of the Saih Hatat window has been affected by a Late Cretaceous, obducti... more The continental material of the Saih Hatat window has been affected by a Late Cretaceous, obduction-related, HP-LT metamorphism below the Oman ophiolite. A high-rate exhumation process is witnessed by the Maastrichtian-Palaeocene onlap onto the blueschist-facies rocks. Drastic metamorphic omissions are documented between the lowest, eclogitic units and the overlying, blueschist-facies ones. Widespread late-metamorphic shear structures point to a top-to-the-NNE detachment, in opposition to the sense of the Late Cretaceous obduction. The inversion of the shearing sense occurred under similar, low temperature conditions in both the blueschist and eclogite-facies units. Admitting that these HP-LT metamorphic rocks formed progressively at various depth in the subducting Arabian margin, a two-stage extensional mechanism of exhumation is suggested: (i) early uplift of the eclogitic rocks up to the blueschists depth by ductile thinning or squeezing of a ‘blind extensional allochthon'; (ii) exhumation of the whole HP-LT metamorphic core complex by inversion of the obduction sole-thrust and isostatic rebound of the lower plate.
Ductile deformation in high-pressure (P</em>)-low temperature (T</em>) conditions due to the west... more Ductile deformation in high-pressure (P</em>)-low temperature (T</em>) conditions due to the westward thrusting of oceanic material onto a continental basement in alpine Corsica is overprinted by a late deformation event with a reverse shear sense (eastward) that took place in less severe P-T</em> conditions. We show that the late deformation can be linked to extension during rifting and spreading of the Liguro Provençal basin from late Oligocene to late-middle Miocene time. Major compressive thrust contacts were reactivated as ductile normal faults and, in some units, only a penetrative eastward shear can be observed. This extension following the thickening of the crust brought tectonic units which underwent very different P- T</em> conditions during the earlier stage into close contact. The Balagne nappe, which shows neither significant ductile deformation nor metamorphism, directly overlies the high-P</em> units. The extensional deformation is distributed through the entire thickness of the nappe stack but is more important along the major thrust contacts, which localize the strain. The geometry of the crustal extension is controlled by that of the early compressive thrusts. The latest structures are east-dipping brittle normal faults which bound the early to middle Miocene Saint Florent half graben.
Geological Society, London, Special Publications, 1996
... The palaeomagnetic study demonstrates that the Ronda massifs registered a magneticfield rever... more ... The palaeomagnetic study demonstrates that the Ronda massifs registered a magneticfield reversal during their progressive cooling. The change from reverse to normal field was fol-lowed by a 46 + 8 clockwise rotation of the massifs. ...
In Oman, the convergence between Arabia and Eurasia resulted in the Late Cretaceous overthrustin... more In Oman, the convergence between Arabia and Eurasia resulted in the Late Cretaceous overthrusting of oceanic crust and mantle lithosphere onto the Arabian continental margin. During this compressional event, a part of the continental plate was subducted to a depth of more than 60 km (0.5 GPa, 250–350 °C to more than 2.0 GPa, 550 °C) resulting in progressive metamorphism of the continental margin sediments, well exposed in the Saih Hatat tectonic window, northeastern Oman Mountains. We attempt to constrain the possibility of one continuous history of extension (starting along the east Arabian continental margin in the Permian) that was followed by one continuous history of convergence starting at 90 Ma near a dead oceanic ridge. This compression resulted in the observed progressive metamorphism by ophiolite overthrusting onto the continental margin. Constraining arguments are the palaeogeographic setting before ophiolite obduction of the As Sifah units and the Hawasina Complex near Ghurba. Detrital chromites in the Triassic–Cretaceous metasediments of the Hawasina Complex are compared with magmatic Semail chromites, and the whole-rock chemistry of these metasediments and associated metabasites are investigated. In contrast to former hypotheses, differences in the chemical composition between detrital and magmatic chromites, and the probable origin of all detrital chromites in the Hawasina Basin from Permian age oceanic rocks, suggest that the high-pressure metamorphic sediments of As Sifah can be considered as part of the basal deposits of the Hawasina Basin.
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