Geochronological, geochemical, and Nd–Hf isotopic constraints on the origin of Neoproterozoic plagiogranites in the Tasriwine ophiolite, Anti-Atlas orogen, Morocco

Samson, Scott D.; Inglis, Jeremy; D’Lemos, R. S.; Admou, Hassan; Blichert‐Toft, Janne; Hefferan, Kevin

doi:10.1016/j.precamres.2004.08.003

Cited by 121 publications

(71 citation statements)

References 44 publications

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“…Rocci et al, 1991 ;Potrel et al, 1996;Kroner et al, 2001 ;Thieblemont et al, 2004 ), the Liberiancycle(2. 95-2.75 Ga;Hurleyetai., 1971 ;Auvray et ai., 1992;Potrel et al, 1998;Key et al, 2008 ), the Eburnian-Birimian cycle (2.2-1.75 Ga; Abouchami et al, 1990;Liegeois et al, 1991;Boher et ai., 1992;Hirdes et ai., 1992;Ait Malek et ai., 1998;Schofield et ai., 2006 ) and the Pan-African orogenic event (760-660 Ma; Leblanc and Lancelot, 1980;Saquaque et al, 1989;Hefferan et al, 2000 ;Thomas et al, 2002;Samson et al, 2004 ). One of the main char- acteristics of the WAC is that no Mesoproterozoic events or rocks are known, suggesting a quiescent period between 1.7 and 1.0 Ca (e.g.…”

Section: Geological Settingmentioning

confidence: 99%

“…The relics of the oceanic crust created (Bou-Azzer Group) are preserved in the Bou-Azzer inlier (Bou-Azzer ophiolite) and Sirwa window (Khzama Complex) as highly sheared allochthonous ophiolite complexes. Dating of plagiogranite intrusions in the Sirwa inlier indicate formation of oceanic crust at 760Ma (U-Pb zircon age; Samson et al, 2004 ), and given the absence of reliable radiometric data on the passive margin sequence, 760 Ma is considered as the minimum age of its formation and this rifting stage may be correlated with the eariyNeoproterozoic break-up of the supercontinent Rodinia. After the creation of the ocean basin, a subduction phase was initiated with island-arc formation (the Iriri Group in the Sirwa inlier; Thomas et al , 2002 ).…”

Section: Pre-to Syn-pan-african Evolutionmentioning

confidence: 99%

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Detrital zircon ages of Neoproterozoic sequences of the Moroccan Anti-Atlas belt

Abati

Aghzer

Gerdes

et al. 2010

Precambrian Research

152

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Section: Geological Settingmentioning

confidence: 99%

Section: Pre-to Syn-pan-african Evolutionmentioning

confidence: 99%

Detrital zircon ages of Neoproterozoic sequences of the Moroccan Anti-Atlas belt

Abati

Aghzer

Gerdes

et al. 2010

Precambrian Research

152

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“…At the end of the Neoproterozoic, the WAC was first subjected to island arc accretion during 760 -660 Ma on its northern and eastern sides, in the Moroccan Anti-Atlas (Thomas et al 2002;Samson et al 2004;D'Lemos et al 2006;Bousquet et al), in the Malian Tilemsi (Caby et al 1989) and in the Gourma area (De la Boisse 1979). During the main Pan-African orogenic phase, the WAC was subjected to convergence on all its boundaries, from the north in the Anti-Atlas (Hefferan et al 2000;Ennih & Liégeois 2001), to the east along the Trans-Saharan belt (Black et al 1979(Black et al , 1994Affaton et al 1991;Attoh & Nude), to the south with the Rockelides and the Bassarides belts and to the east with the Mauritanides belt (Villeneuve), with several thrust sheets preserved on the craton itself, such as in Mali (Caby et al).…”

Section: The West African Cratonmentioning

confidence: 99%

“…dated at 761 + 2 Ma and 762 + 2 Ma at Taswirine (Sirwa area; U -Pb zircon; Samson et al 2004) and a tonalitic migmatite at 743 + 14 Ma at Iriri (Sirwa area; U -Pb zircon; Thomas et al 2002). The zircon rims of the latter gave an age of 663 + 13 Ma, interpreted as the age of the metamorphism that accompanied the island arc accretion towards the craton (Thomas et al 2002).…”

Section: The West African Craton Of the Moroccan Metacratonic Anti-atmentioning

confidence: 99%

The boundaries of the West African craton, with special reference to the basement of the Moroccan metacratonic Anti-Atlas belt

Ennih

Liégeois

2008

172

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The West African craton (WAC) was constructed during the Archaean and the c. 2 Ga Palaeoproterozoic Eburnian orogeny. Mesoproterozoic quiescence at c. 1.7-1.0 Ga allowed cratonization. In the absence of Mesoproterozoic activity, there are no known WAC palaeogeographical positions for that time. At the beginning of the Neoproterozoic, the WAC was affected by several extensional events suggesting that it was subjected to continental breakup. The most important event is the formation of the Gourma aulacogen in Mali, and the Taoudeni cratonic subcircular basin and deposition of platform sediments in the Anti-Atlas. At the end of the Neoproterozoic, the WAC was subjected to convergence on all its boundaries, from the north in the Anti-Atlas, to the east along the Trans-Saharan belt, to the south along the Rockelides and the Bassarides and to the east along the Mauritanides. This led to a partial remobilization of its cratonic boundaries giving rise to a metacratonic evolution. The WAC boundaries experienced Pan-African Neoproterozoic to Early Cambrian transpression and transtension, intrusion of granitoids and extrusion of huge volcanic sequences in such as in the Anti-Atlas (Ouarzazate Supergroup). Pan-African tectonism generated large sediment influxes around the WAC within the Peri-Gondwanan terranes whose sedimentary sequences are marked by distinctive zircon ages of 1.8-2.2 Ga and 0.55-0.75 Ga.WAC rocks experienced Pan-African low grade metamorphism and large movements of mineralizing fluids. In the Anti-Atlas, this Pan-African metacratonic evolution led to remobilization of REE in the Eburnian granitoids due to the activity of F-rich fluids linked to extrusion of the Ouarzazate Supergroup. During the Phanerozoic, the western WAC boundary was subjected to the Variscan orogeny, for which it constituted the foreland and was, therefore moderately affected, showing typical thick-skin tectonics in the basement and thin-skin tectonics in the cover. During the Mesozoic, the eastern and southern boundaries of the WAC were subjected to the Atlantic opening including Jurassic dolerite intrusion and capture of its extreme southern tip by South America. The Jurassic is also marked by the development of rifts on its eastern and northern sides (future Atlas belt). Finally, the Cenozoic period was marked by the convergence of the African and European continents, generating the High Atlas range and Cenozoic volcanism encircling the northern part of the WAC. The northern metacratonic boundary of the WAC is currently uplifted, forming the Anti-Atlas Mountains.The boundaries of the WAC, metacratonized during the Pan-African orogeny have been periodically rejuvenated. This is a defining characteristic of the metacratonic areas: rigid, stable cratonic regions that can be periodically cut by faults and affected by magmatism and hydrothermal alteration -making these areas important for mineralization.

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“…This inlier consists mostly of a Panindicated by the presence of ophiolites at Bou Azzer and African ophiolitic complex that has recently been dated at Siroua. the neighboring Siroua massif at 761±2 Ma (U/Pb on The main objective of the present study is t o zircons from plagiogranites (Samson et al, 2004). The characterize the petrology and geochemistry and t o Igherm, Ifni and Kerdous inliers the focus of the present propose a geodynamic setting for the emplacement of study belong to the southwestern domain on the these Neoproterozoic mafic rocks within the more general Northern margin of the West-African Craton.…”

Section: Introductionmentioning

confidence: 91%

Geochemical and Geodynamic Implications of Mafic Dykes of the Iguerda Inlier (Central Anti-Atlas, Morocco)

Hassan¹,

Aouli²,

Amaouain³

2010

Online J. of Earth Sciences

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Abstract:In the inlier of Iguerda (Anti-Atlas, Morocco), the Neoproterozoic basic rocks consist dominantly of dolerite dykes intruded the Palaeoproterozoic basement and overlain by the late Neoproterozoic series. Major and immobile trace elements (HFS and REE elements) allow to identify 2 groups of mafic rocks: the 1st is tholeiitic, the 2nd shows a transitional affinity with chondrite normalized REE patterns more fractionated. Their geochemical signatures display similarities with those of intraplate series found in young continental rift structures (they are enriched in incompatible elements, excepted Y and Yb, relative to N-MORB but they are depleted in Nb). This preorogenic magmatism can be related to begining of rifting in the northern border of the West-African craton which allows the emplacement of bassins of Pan-African belt of Anti-Atlas. This rifting may be related to the opening of an oceanic domain in Siroua and Bou-Azzer areas.

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Geochronological, geochemical, and Nd–Hf isotopic constraints on the origin of Neoproterozoic plagiogranites in the Tasriwine ophiolite, Anti-Atlas orogen, Morocco

Cited by 121 publications

References 44 publications

Detrital zircon ages of Neoproterozoic sequences of the Moroccan Anti-Atlas belt

Detrital zircon ages of Neoproterozoic sequences of the Moroccan Anti-Atlas belt

The boundaries of the West African craton, with special reference to the basement of the Moroccan metacratonic Anti-Atlas belt

Geochemical and Geodynamic Implications of Mafic Dykes of the Iguerda Inlier (Central Anti-Atlas, Morocco)

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