Tectonic evolution of the Rehamna metamorphic dome (Morocco) in the context of the Alleghanian-Variscan orogeny

Chopin, Francis; Corsini, Michel; Schulmann, Karel; Houicha, Mohamed El; Ghienne, Jean‐François; Edel, Jean–Bernard

doi:10.1002/2014tc003539

Cited by 44 publications

(63 citation statements)

References 86 publications

(258 reference statements)

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“…Michard et al () suggested that HT‐LP metamorphism accompanying this compressive event in the Rehamna and the Jebilet was controlled by an older thermal anomaly in relation with the Late Devonian‐Early Carboniferous intracontinental rifting stage. This hypothesis is also supported by Chopin et al () and Wernert et al () for the Rehamna massif. Our results have further confirmed this model for the Jebilet massif.…”

Section: Discussionsupporting

confidence: 71%

“…Similar ages have been obtained on bimodal intrusions in the Western Meseta (ranging between 349 and 339 Ma; Ait Lahna et al, ). As shown by Chopin et al () and Wernert et al () in the Rehamna massif and by us in the Jebilet, this important magmatism testifies to an active thermal anomaly throughout this area, probably caused by mantle heat advection.…”

Section: Discussionsupporting

confidence: 68%

“…Similar deformation is well known elsewhere in MMD; in the Massif Central, for instance, Late Pennsylvanian‐Early Permian structures are characterized by NNE to NE trending folds with a NW or SE kinematic, followed by ductile‐brittle reverse faults and strike‐slip shear zones (Figure e). The Rehamna massif was also affected by NW‐SE to WNW‐ESE crustal shortening that followed the exhumation of the lower metamorphic unit (Figure e; Baudin et al, ; Chopin et al, ). The latter event is associated with HT‐LP metamorphism and syntectonic to posttectonic magmatism dated between 292 and 275 Ma (Chopin et al, ), with a thermal peak age at ~276 Ma (Wernert et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Recently, based on structural analysis coupled with geochronological data in the Rehamna massif, Chopin et al () proposed another tectonic evolution model for the MMD, caused by a change in orientation of the main tectonic stresses. This change would have induced two distinct compressional events: first, a Late Carboniferous N‐S compressional deformation resulting in crustal thickening and folding by allochthonous nappe stacking, followed by an Early Permian orthogonal NW‐SE transpressional event refolding the older (phase‐1) structures.…”

Section: Introductionmentioning

confidence: 99%

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The Geological Evolution of the Variscan Jebilet Massif, Morocco, Inferred From New Structural and Geochronological Analyses

et al. 2018

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The present work aims at understanding the tectonic evolution of the Jebilet massif, Morocco, during the Late Paleozoic as constrained by structural, metamorphic, and geochronological studies. From Late Devonian to Early Carboniferous, bordering faults controlled the opening of the Jebilet intracontinental basin (D0 stage) as shown by sedimentary infill. This episode was accompanied by a magmatic activity, newly dated between 358 ± 7 Ma and 336 ± 4 Ma. The first record of the Variscan event affected the Jebilet by the Late Visean‐Namurian and is represented by allochthonous superficial nappes emplaced at shallow depth in a moderately lithified sedimentary succession. D1 also developed regional‐scale recumbent folds trending E‐W that may suggest N‐S crustal shortening not generating crustal thickening nor contributing to metamorphism. The main Variscan D2 episode consists of a progressive evolution from bulk coaxial deformation to noncoaxial dextral transpression consistent with NW‐SE horizontal shortening, resulting in a moderate thickening. This episode was accompanied by HT‐LP metamorphism and syntectonic intrusions controlled by an inherited thermal anomaly in relation with the intracontinental rifting stage (D0). Based on previous age determinations from syntectonic leucogranite and metamorphic rocks, D2 is dated between 310 and 280 Ma. The tectono‐metamorphic evolution of the Jebilet massif can be correlated with a plate‐tectonic scenario evolving from, first a Late Devonian‐Early Carboniferous basin formation during stretching of the north‐Gondwana margin and initiation of the Paleotethys Ocean, and, second, to a Late Carboniferous‐Early Permian ocean closure (Rheic or Paleotethys Oceans depending of scenarios) that resulted in the final Variscan‐Alleghanian tectonics.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionsupporting

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Geological Evolution of the Variscan Jebilet Massif, Morocco, Inferred From New Structural and Geochronological Analyses

et al. 2018

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“…However, the northern margin of the Gondwana supercontinent exposed in central Morocco reveals Upper Carboniferous metamorphism and deformation, which is located away from convergent plate boundaries (Piqué & Michard, ; Hoepffner et al ., , ; Michard et al ., ) and may also represent a typical intracontinental orogen (Hoepffner et al ., ). This orogenic system exemplified by the Rehamna massif was recently interpreted as reflecting the shortening of peri‐Gondwanan Devonian to Lower Carboniferous basins during Upper Carboniferous to Lower Permian (Chopin et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Tectonometamorphic evolution of an intracontinental orogeny inferred from P–T–t–d paths of the metapelites from the Rehamna massif (Morocco)

Schulmann

Chopin

Štípská

et al. 2016

Journal Metamorphic Geology

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New petrographic and microstructural observations, mineral equilibria modelling and U/Pb (monazite) geochronological studies were carried out to investigate the relationships between deformation and metamorphism across the Rehamna massif (Moroccan Variscan belt). In this area, typical Barrovian (muscovite to staurolite) zones developed in Cambrian to Carboniferous metasedimentary rocks that are distributed around a dome‐like structure. First assemblages are characterized by the presence of locally preserved andalusite, followed by prograde evolution culminating at 6 kbar and 620 °C in the structurally deepest staurolite zone rocks. This Barrovian sequence was subsequently uplifted to supracrustal levels, heterogeneously reworked at greenschist facies conditions, which was followed locally by static growth of andalusite, indicating heating to 2.5–4 kbar and 530–570 °C. The 206Pb/238U monazite age of 298.3 ± 4.1 Ma is interpreted as minimum age of peak metamorphic conditions, whereas the ages of 275.8 ± 1.7 Ma and 277.0 ± 1.1 Ma date decompression and heating at low pressure, in agreement with previous dating of Permian granitoids intruding the Rehamna massif. The prograde metamorphism occurred during thickening and associated horizontal flow in the deeper crust (S1 horizontal schistosity). The horizontally disposed metamorphic zones were subsequently uplifted by a regional scale antiform during ongoing N–S compression. The re‐heating of the massif follows late massive E–W shortening, refolding and retrograde shearing of all previous fabrics coevally with regionally important intrusions of Permian granitoids. We argue that metamorphic evolution of the Rehamna massif occurred several hundred kilometres from the convergent plate boundaries in the interior of continental Gondwanan plate. The tectonometamorphic history of the Rehamna massif is put into Palaeozoic plate tectonic perspective and Late Carboniferous reactivation of (Devonian)–Early Carboniferous basins formed during stretching of the north Gondwana margin and formation of the Palaeotethys Ocean. The inherited heat budget of these magma‐rich basins plays a role in the preferential location of this intracontinental orogen. It is shown that rapid transition from lithospheric stretching to compression is characterized by specific HT type of Barrovian metamorphism, which markedly differs from similar Barrovian sequences along Palaeozoic plate boundaries reported from Variscan Europe.

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European Variscan orogenic evolution as an analogue of Tibetan‐Himalayan orogen: Insights from petrology and numerical modeling

et al. 2016

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Tectonic evolution of the Rehamna metamorphic dome (Morocco) in the context of the Alleghanian-Variscan orogeny

Cited by 44 publications

References 86 publications

The Geological Evolution of the Variscan Jebilet Massif, Morocco, Inferred From New Structural and Geochronological Analyses

The Geological Evolution of the Variscan Jebilet Massif, Morocco, Inferred From New Structural and Geochronological Analyses

Tectonometamorphic evolution of an intracontinental orogeny inferred from P–T–t–d paths of the metapelites from the Rehamna massif (Morocco)

European Variscan orogenic evolution as an analogue of Tibetan‐Himalayan orogen: Insights from petrology and numerical modeling

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