U–Pb baddeleyite and zircon ages of 2040Ma, 1650Ma and 885Ma on dolerites in the West African Craton (Anti-Atlas inliers): Possible links to break-up of Precambrian supercontinents

Kouyaté, Djiky; Söderlund, Ulf; Youbi, Nasrrddine; Ernst, Richard E.; Hafid, Ahmid; Ikenne, Moha; Soulaı̈mani, Abderrahmane; Bertrand, Hervé; Janati, M’hamed El; Chaham, Khalid Rkha

doi:10.1016/j.lithos.2012.04.028

Cited by 84 publications

(30 citation statements)

References 45 publications

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“…Dolerite dykes have been recently discovered in the Anti‐Atlas belt with emplacement ages of c . 1.65 Ga (Kouyaté et al ., ) and c . 1.4 Ga (El Bahat et al ., ; Michard & Gasquet, ; Söderlund et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Provenance of the HP–HT subducted margin in the Variscan belt (Cabo Ortegal Complex, NW Iberian Massif)

Albert

Arenas

Gerdes

et al. 2015

Journal Metamorphic Geology

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The Variscan Upper Allochthon is a continental-affinity terrane that recorded a Cambrian-Ediacaran magmatic arc generation, a subsequent transition to a passive margin, and a collision-related high-P metamorphism during the Devonian-Carboniferous amalgamation of Pangea. The objective of this article is to decipher which continental margin subducted in the Devonian high-P-high-T (HP-HT) event. To do so, a provenance study is presented using combined U-Pb (n = 613) and Lu-Hf (n = 463) isotopic LA-ICP-MS zircon analyses and Sm-Nd whole-rock (n = 5) determinations. These analyses have been performed on five samples of the Banded Gneisses (Cabo Ortegal Complex, NW Iberia), which forms a part of the HP-HT bottom member of the Upper Allochthon. PalaeozoicNeoproterozoic zircon ages (34.7%) have a maximum abundance at 522-512 Ma, peaks at 575, 561, 545 Ma and minor abundance peaks between 780 and 590 Ma, and show from their Lu-Hf compositions a volcanic arc mixing pattern. This arc was probably related to the Cadomian arc system. The Mesoproterozoic population is scarce and scattered (2.8%), and due to its Lu-Hf pattern, it is proposed that this population is also West Africa Craton derived. The Paleoproterozoic population (39.6%) is concentrated at 2.07 Ga and it is linked to the Eburnean Orogeny, where depleted mantle derived magmas intruded an Archean craton margin. This craton is represented by the Archean population (22.8%), which is grouped at 3.0, 2.68-2.61 and 2.52-2.48 Ga, and shows long-term reworking processes and at least two juvenile magma intrusions. These data show that the Variscan Upper Allochthon has a West African provenance and therefore, it strongly suggests that the NW Iberian allochthonous complexes and their correlative European terranes are also West Africa derived. These results allow us to finally clarify that the first high-P event, recorded during the eo-Variscan amalgamation of Pangea, was attained by the subduction of the margin of Gondwana under Laurussia.

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Section: Discussionmentioning

confidence: 97%

Provenance of the HP–HT subducted margin in the Variscan belt (Cabo Ortegal Complex, NW Iberian Massif)

Albert

Arenas

Gerdes

et al. 2015

Journal Metamorphic Geology

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“…The oldest metamorphic and magmatic rocks form the West African Craton (WAC), which crops out in the Reguibat Shield, and are related to the Palaeoarchean–Leonian and Liberian orogenic cycles (3.5–2.73 Ga) (Auvray et al., ; Hurley, Leo, White, & Fairbairn, ; Key et al., ; Potrel, Peucat, & Fanning, ; Potrel et al., ; Rocci, Bronner, & Deschamps, ). Palaeoproterozoic meta‐sedimentary and igneous rocks, cropping out in the Reguibat Shield and several inliers in the Anti‐Atlas, form part of the N margin of the WAC and are related to the Eburnian–Birimian orogenic cycle (2.3–1.65 Ga) (Abouchami, Boher, Michard, & Albarede, ; Aït Malek, Gasquet, Bertrand, & Leterrier, ; Boher, Abouchami, Michard, Albarede, & Arndt, ; Gasquet et al., ; Kouyaté et al., ; Liégeois, Claessens, Camara, & Klerkx, ; Schofield et al., ; Walsh, Aleinikoff, Benziane, Yazidi, & Armstrong, ). Rocks associated with the Kibaran–Grenvillian orogenic cycle (900–1,400 Ma) have only been identified to the E of the Reguibat shield in the Hoggar area of Algeria (Grant, Hickman, Burkholder, & Powell, ).…”

Section: Geologic Settingmentioning

confidence: 99%

Detrital zircon U–Pb provenance and palaeogeography of Triassic rift basins in the Marrakech High Atlas

2018

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The Marrakech High Atlas contains some of the best exposures of the Triassic early-rift strata related to Atlantic opening in NW Africa. We present the first detrital zircon U-Pb data of five Triassic redbed samples from the Tizi n'Test basin to quantify sediment provenance, transport and dispersal patterns during early rifting.These U-Pb ages document dominant sediment sourcing from the south, the Anti-Atlas domain, with very limited to absent input from the Variscan Meseta domain to the north. This combined with stratigraphic and thermochronologic information points to a highly asymmetric palaeogeography during Triassic rifting. Furthermore, the occurrence of Archaean detrital zircon grains in Triassic sandstone, likely recycled from the Reguibat shield, suggests the presence of a fully developed regional drainage system with rivers and catchments reaching hundreds of kilometres into the hinterland of the rift flank.

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“…In such cases, the underlying mantle may warm, expand, decrease in density, become buoyant and exert upward and outward tractions on the base of the lithosphere. High volumes of emplaced magmas called Large Igneous Provinces may indicate the influence of upwelling mantle at these extension zones; the inferred melting of mantle at elevated temperatures may support the hypothesis of mantle-driven breakup (Bond et al 1984;Li et al 1999;Dalziel et al 2000;Ernst et al 2005;Hou et al 2008;Kouyaté et al 2013). The Central Atlantic Magmatic Province emplaced during the breakup of Pangaea may be the largest preserved Large Igneous Province in the geological record (Ruiz-Martínez et al 2012).…”

Section: Previous Workmentioning

confidence: 85%

How subduction broke up Pangaea with implications for the supercontinent cycle

Keppie

2015

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Mechanisms that can explain the Mesozoic motion of Pangaea in a palaeomagnetic mantle reference frame may also be able to explain its breakup. Calculations indicate that Pangaea moved along a non-rigid path in the mantle frame between the late Triassic and early Jurassic. The breakup of Pangaea may have happened as a response to this non-rigid motion. Tectonic forces applied to the margins of Pangaea as a consequence of subduction at its peripheries can explain both the motion and deformation of Pangaea with a single mechanism. In contrast, mantle forces applied to the base of Pangaea appear to be inconsistent with the kinematic constraints and do not explain the change in supercontinent motion that accompanied the breakup event. Top-down plate tectonics are inferred to have caused the breakup of Pangaea. Strong coupling between the mantle and lithosphere may not have been the case during the Phanerozoic eon when the Pangaean supercontinent formed and subsequently dispersed.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.The mechanisms responsible for plate tectonic change on Earth have been linked to the different stages of the supercontinent cycle (Worsley et al.

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U–Pb baddeleyite and zircon ages of 2040Ma, 1650Ma and 885Ma on dolerites in the West African Craton (Anti-Atlas inliers): Possible links to break-up of Precambrian supercontinents

Cited by 84 publications

References 45 publications

Provenance of the HP–HT subducted margin in the Variscan belt (Cabo Ortegal Complex, NW Iberian Massif)

Provenance of the HP–HT subducted margin in the Variscan belt (Cabo Ortegal Complex, NW Iberian Massif)

Detrital zircon U–Pb provenance and palaeogeography of Triassic rift basins in the Marrakech High Atlas

How subduction broke up Pangaea with implications for the supercontinent cycle

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