Ait Lahna Abdelhak

• Ph. D.
• Assistant professor at University Ibn Zohr - Agadir

Post-collisional volcanism provides valuable insights into mantle dynamics, crustal processes, and mechanisms driving orogen uplift and collapse. This study presents geological, geochemical, and geochronological data for Ediacaran effusive and pyroclastic units from the Taghdout Volcanic Field (TVF) in the Siroua Window, Anti-Atlas Belt. Two erupti...

The migration and composition of magmatism over time can provide important insights into the tectonic evolution of an orogen like the Variscan Belt. To identify Large Igneous Provinces (LIPs), key criteria include large magmatic volume, intraplate-origin volcanic geochemistry, and significant plumbing systems. Based on such criteria, we present evi...

The Mesetian Domain represents a part of the Moroccan Variscan belt. It’s separated by the Middle Atlas folded belt into two structural domains: the Eastern and the Western Meseta. The latter comprise the basins of Jebilets, Rehamna and Fourhal (Central Hercynian Massif of Morocco) which show important similarities of tectonosedimentary evolution d...

The Assif n’Bougmmane gneiss complex comprises meta-igneous units, paragneiss, schist, and muscovite-bearing granite. The complex occurs at Bou Azzer, Oumlil, Tazigzaout, Hassi El Mnissi, and Assif n‘Bougmmane windows in the southern part of the Bou Azzer inlier in the Central Anti- Atlas (Morocco). To determine the tectonomagmatic setting, the ori...

The Ougnat inlier is located in the easternmost portion of the pan-African Anti-Atlas Belt, Morocco, which itself is attached to the northern margin of the West African Craton (WAC). Numerous mafic and felsic dyke swarms and sill complexes cross-cut the Precambrian basement including the Saghro Group and the Ouarzazate Supergroup. The latter is com...

The lower Anti-Atlas Supergroup of the Anti-Atlas Belt (Lkest-Taghdout Group sensu Thomas et al., 2004) is one of the most important Proterozoic lithostratigraphic units on the northern part in the West African Craton (WAC, Anti-Atlas Belt, Morocco). This yet poorly dated supergroup consists essentially of basalts, quartzites, and stromatolitic/ool...

A conspicuous dyke swarms of intermediate dykes (microdiorites) and felsic dykes (microgranites) cross-cuts hercynian plutons and paleozoïc metasedimentary basement of Rehamna, Jbilets (Western Meseta) and Azegour (High Atlas). The microdiorites dykes dominantly alkaline (presence of kaersutite, Ti/V= 61-85; Zr/Y=2-12 and La/Yb=15-23) show also som...

A number of conspicuous mafic and felsic dyke swarms cross-cut the Precambrian basement of the Ouzellarh-Sirwa promontory in the High Atlas (Douar Eç-çour) and Anti-Atlas (Assarag). Here, they are named the Douar Eç-çour-Assarag dyke swarms. The Douar Eç-çour mafic dyke swarms show a NNE, NE to ENE-trending, whereas the trends are E-W, NS, NNE, NE,...

Owing to the rarity and low quality of paleomagnetic data, great difficulties exist when dealing with the paleogeography of the West African Craton (WAC) prior to the Paleozoic. A dozen recently-dated Proterozoic mafic intrusions in the Anti-Atlas Belt (AAB) of Morocco opens the opportunity for providing robust paleomagnetic poles that could constr...

Development and concentration of many ore deposits at the regional and district scales closely depend on structural geology, especially in polydeformed basements. The superposition of many deformation periods highlights the complexity of the structural context and expected potential location of mineralization zones. The formation and concentration...

The lower Anti-Atlas Supergroup of the Anti-Atlas Belt (Lkest-Taghdout Group sensu Thomas et al., 2004) is one of the most important Proterozoic lithostratigraphic units on the northern part in the West African Craton (WAC, Anti-Atlas Belt, Morocco). This yet poorly dated supergroup consists essentially of basalts, quartzites, and stromatolitic/ool...

The NE–SW trending Tiddas Souk Es-Sebt des Ait Ikko (TSESDAI) basin, located at 110 km southeast of Rabat, in the region of Khmesset between the village of Tiddas and Souk Es-Sebt des Ait Ikko, is the third largest late Palaeozoic continental trough in the northern Central Moroccan Meseta. It is a ~20 km long and ~2–3 km wide basin, comprising main...

The location of the West African craton (WAC) has been poorly constrained in the Paleoproterozoic–Mesoproterozoic supercontinent Nuna (also known as Columbia). Previous Nuna reconstruction models suggested that the WAC was connected to Amazonia in a way similar to their relative position in Gondwana. By an integrated paleomagnetic and geochronologi...

Abstract: Recent U-Pb igneous ages obtained in the SW Domain of the Anti-Atlas are not consistent with the model proposed in the recently published paper by Errami et al. (2020). The formations of the Taghdoute and Lkest groups in the SW Domain, also known as the “limestones and quartzites” series, were previously considered to have a Cryogenian ag...

Earth has gone through periods of cooling including global, near global, or regional glaciations, which are observed in the Archean, Paleoproterozoic, Neoproterozoic, Ordovician, Permo‐Carboniferous, and Cenozoic times. We review the mechanisms by which large igneous provinces (LIPs) and silicic LIPs (SLIPs) can cause global cooling. Then we invest...

The Khzama ophiolite is a highly dismembered complex located in the Siroua inlier of the Moroccan Anti-Atlas Belt. It consists of ultramafic rocks, cumulate gabbros, sheeted dikes, pillow lavas, and an overlying volcano-sedimentary sequence. Three main tectonic slices of sheeted dike complexes are studied in detail along three rivers, exposing well...

West African Craton (WAC) has essentially no pre-Ediacaran paleomagnetic constraints, yielding large uncertainties in its position in Proterozoic supercontinents, Rodinia and Nuna. Recent geochronological results distinguish at least five mafic dyke swarms in the Anti-Atlas Belts, Morocco, namely 2.04 Ga, 1.75 Ga, 1.65 Ga, 1.41-1.38 Ga, and 0.88-0....

U–Pb geochronology of magmatic and detrital zircons (Zenaga and Bou Azzer-El Graara inliers, Anti-Atlas Belt, Morocco) and a reassessment of the published constraints suggest a revised stratigraphic framework for the lower Anti-Atlas Supergroup. Five, major unconformity-bounded lithostratigraphic packages are here distinguished: the two lower units...

The Neoproterozoic Anti-Atlas belt (Morocco) is a key segment in tracing the history of the northern margin of the West African craton (WAC) from Rodinia breakup to Gondwana assembly. In order to constrain geodynamic events related to rifting and convergence and their stratigraphic records, a radiometric study was carried out on the volcano-sedimen...

Large igneous provinces and associated silicic magmatism can have a significant global climatic effect, so we explored the relationship between the large igneous province record and the ca. 580 Ma Gaskiers glaciation. The late Ediacaran glaciation exists on at least 14 different paleocontinental blocks, and assuming synchroneity, this Gaskiers glac...

The Taghdout Group is a passive margin sequence deposited during rifting and break-up of the northern margin of the West African craton (WAC), culminating with the creation of an oceanic basin between the northern edge of the WAC and an unknown terrane. However, the age of this passive margin has been poorly constrained. It was previously thought t...

In the Tagragra of Akka Inlier (Anti-Atlas, West African craton, Morocco), the Paleoproterozoic basement is crosscut by numerous dykes with various trends, and mostly of uncertain age. Four baddeleyite fractions from a NE trending doleritic dyke were analyzed using the ID-TIMS U-Pb method and indicate an emplacement age of 1359 ± 6 Ma (upper interc...

The 617-520 Ma CIMP was emplaced in multiple pulses (likely representing multiple LIPs) during Ediacaran-Cambrian time and has been linked to the disruption of the Rodinia supercontinent leading to the opening of the Central Iapetus Ocean. CIMP is well represented in Laurentia and Baltica but also present on other formerly attached blocks such as t...

Large Igneous Provinces (LIPs) and Silicic LIPs (SLIPs) can have a significant global climatic effect and we explore the relationship between the LIP record and the c. 580 Ma Gaskiers glaciation. The late Ediacaran glaciation exists on at least fourteen different paleocontinents, and assuming synchroneity, this Gaskiers glaciation was likely of sho...

In the central Anti-Atlas a Pan-African shear zone materialize a suture which cross the Bou Azzer and Siroua inliers where a ophiolite crop out. This ophiolite complex is considered among the oldest and more famous in the world, despite it was partially dismembered by PanAfrican tectonics (ca. 650Ma). A very important Sheeted Dyke Complex (SDC) is...

Large Igneous Provinces (LIPs) and Silicic LIPs (SLIP) can have significant global climatic effects including causing mass extinction events, via a complex web of changes (characteristically rapid) in atmospheric/oceanic acidification, oceanic anoxia, sea level, toxic metal input (e.g. Hg), and most significantly in temperature, both warming and co...

Large Igneous Provinces (LIPs) and Silicic LIPs (SLIP) can have significant global climatic effects including causing mass extinction events, via a complex web of changes (characteristically rapid) in atmospheric/oceanic acidification, oceanic anoxia, sea level, toxic metal input (e.g. Hg), and most significantly in temperature, both warming and co...

Large Igneous Provinces (LIPs) of Paleozoic and Proterozoic ages are in general deeply eroded. They are represented by deep-level plumbing systems consisting of giant dyke swarms, sill provinces, layered intrusions and, more rarely, locally preserved mafic lava flows. Here we demonstrate that the ca. 885 Ma mafic dyke swarms of the Ifzwane Suite an...

The NE-SW Tsesdai basin (110 km to the SE of Rabat) is the third largest Late Palaeozoic continental trough in the northern Central Moroccan Meseta. It is <20 km long and ~2-3 km wide, comprising mixed volcano-sedimentary reddish-purple Permian rocks that rest on Visean deep marine siliciclastic sediments, overlain by the Triassic and Cenozoic form...

Regional mafic dyke swarms and sill complexes occur in a wide variety of geological and tectonic settings and their comprehensive study through space and time is crucial for understanding several geological events, especially the extent of Large Igneous Provinces (LIPs) and ancient supercontinents (e.g., Ernst, 2014 and references therein). The Cen...

A conspicuous dyke swarms of intermediate dykes (microdiorites/lamprophyres) and felsic dykes (microgranites) cross-cuts hercynian plutons and paleozoïc metasedimentary series of Rehamna, Jbilets (Western Meseta) and Azegour (High Atlas). The lamprophyres dykes dominantly alkaline (presence of kaersutite, Ti/V= 61-85; Zr/Y=2-12 and La/Yb=15-23) sho...

The Permian volcanism of the Eastern Rehamna massif (Western Meseta) displays two large outcrops: (i) Mechra Ben Abbou to the N and (ii) Benguerir to the S. The volcanism of Mechra Ben Abbou is often interbedded in Stephanian/Autunian sandstones/conglomerates (e.g., Gigout, 1952; Hoepffner, 1982; etc.), and appears as massive/fluidal andesitic lava...

The Rehamna Massif is located in the Western Meseta. It is divided into three main structural blocks separated by the Median (part of the Western Meseta Shear Zone) and the Ouled Zednes faults (Michard et al.,2010, Chopin et al., 2014 and references therein). The three blocks are the Western Rehamna, which belongs to the Coastal Block, and the Cent...

The Rehamna Massif is located in the Western Meseta. It is divided into three main structural blocks separated by the Median (part of the Western Meseta Shear Zone) and the Ouled Zednes faults (Michard et al.,2010, Chopin et al., 2014 and references therein). The three blocks are the Western Rehamna, which belongs to the Coastal Block, and the Cent...

The Precambrian stratigraphy of the Anti-Atlas comprises several groups, some of them with poor age constraints. The Tizi n’Taghatine Group (Taghdout or Lkest Group,) of the Anti-Atlas (Morocco, northern portion of the West African craton, WAC) consists essentially of basalts, quartzites, and stromatolitic/oolitic carbonates and represents a passiv...

The 615-540 Ma Central Iapetus Magmatic Province (CIMP) was emplaced in multiple pulses during Ediacaran-Cambrian times, and has been linked to the disruption of the Rodinia supercontinent leading to the opening of the Central Iapetus Ocean. It is well represented in Laurentia and Baltica but also present on other formerly attached blocks such as t...

The 615-540 Ma Central Iapetus Magmatic Province (CIMP) was emplaced in multiple pulses during Ediacaran-Cambrian times, and has been linked to the disruption of the Rodinia supercontinent leading to the opening of the Central Iapetus Ocean. It is well represented in Laurentia and Baltica but also present on other formerly attached blocks such as t...

Morocco hosts a Dyke Swarm Bonanza! Remarkable mafic dyke and sill swarms (plumbing systems of Large Igneous Provinces, LIPs) have been recognized in the Sahara and in most inliers in the Anti-Atlas of southern Morocco. In the Sahara, numerous mafic dyke swarms with various trends are found in the southwestern and oldest portion of the Reguibat Shi...

The Variscides or Hercynides of the Meseta domain include all the Paleozoic massifs north of the South Atlas Fault, except the Ouzellarh Block of the Marrakech High Atlas which belongs to the Anti-Atlas Paleozoic domain. During Early Carboniferous, the mesetian basins of Jebilets, Rehamna and Fourhal (Central Hercynian Massif of Morocco) of western...

The Pre-Panafrican segment of the Anti-Atlas lies on the western and central Anti-Atlas and constitute the northern edge of the West African craton (WAC), bounded by the Major Anti-Atlas Fault and the Reguibate shield. This segment consist of an Eburnean basement (ca.~2.03Ga) unconformably overlain by 2km thick succession formally named Tizi n’Tagh...

It is conventionally interpreted that the Precambrian series of the Anti-Atlas are composed of a Paleoproterozoic basement, unconformably overlain by a Neoproterozoic to Cambrian cover groups. The Paleoproterozoic basement, consists of a siliciclastic series intruded by granitoids emplaced around 2 Ga. The Neoproterozoic cover group has been divide...

It is conventionally interpreted that the Precambrian series of the Anti-Atlas are composed of a Paleoproterozoic basement, unconformably overlain by a Neoproterozoic to Cambrian cover groups. The Paleoproterozoic basement, consists of a siliciclastic series intruded by granitoids emplaced around 2 Ga. The Neoproterozoic cover group has been divide...

The Anti-Atlas belt of southern Morocco is situated on the northern edge of the West African craton (WAC). It corresponds to a broad anticlinorium some 800 km long and 200 km wide, trending ENE-WSW, parallel to the Alpine High Atlas chain. The Precambrian basement outcrops in several inliers (“boutonnières”) within late Ediacaran and younger units...

L’Anti-Atlas central est jalonné par une suture panafricaine le long de laquelle affleure, à Bou Azzer et à Siroua, un complexe ophiolitique considéré parmi les plus anciens au monde. Cette ophiolite, très disloquée et démembrée par les orogenèses panafricaines (environ 650Ma), présente tous les termes lithologiques d’une ophiolite complète. Cette...

La boutonnière de Bou Azzer El Graara, située dans l’Anti-Atlas central est considérée comme un jalonnement de l’accident majeur de l’Anti-Atlas. Cette boutonnière est l’endroit le plus étudié de l’Anti-Atlas. C’est une zone clé de la géologie des terrains protérozoïques et panafricains de l’Anti-Atlas où ont été définis la majorité des événements...

Ophiolites represent fragments of upper mantle and oceanic crust that were incorporated into continental margins during continent-continent and arc-continent collisions, ridge-trench interactions, and/or subduction-accretion events. They are generally found along suture zones in both collisional-type (i.e., Alpine, Himalayan, Appalachian) and accre...