Nasrrddine Youbi

Cadi Ayyad University | UCAM · Department of Geology

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 geochemical composition of Ocean Island Basalts (OIBs) from the Azores reflects the spatial distribution, shape, and temporal evolution of small-scale geochemical heterogeneities within their mantle plume source. Here, we investigate the time-related evolution of volcanism at São Jorge Island, Central Azores. New field observations, a magnetic...

Several synthetic papers have been published about the geological structure of the threeWest African fold belts (Rokelides, Bassarides and Mauritanides), which were attached to the western margin of the West African Craton. Owing to the paucity of radiometric ages, some orogens and tectonic events have previously been confused and little consensus...

GRABEN SYSTEMS (DYKE SWARMS) OF THE MBOKOMU MONS REGION, ALONG PARGA CHASMATA, 2400 KM SE OF ATLA REGIO, VENUS

The nature of the magma plumbing system of Large Igneous Provinces is still poorly understood. Among these exceptional magmatic events from Earth’s past, the end-Triassic Central Atlantic Magmatic Province (CAMP) and the end-Cretaceous Deccan Traps (Deccan) coincided in time with two of the most catastrophic biotic crises during the Phanerozoic. In...

LAVA FLOWS AND GRABEN SYSTEMS (DYKE SWARMS) OF THE MBOKOMU MONS REGION ALONG PARGA CHASMATA, SE FROM ATLA REGIO, VENUS.

DYKE SWARMS (BASED ON OVERLYING GRABEN SETS) OF EASTERN OVDA REGIO, VENUS

Paleogeography of the Ediacaran Period has remained poorly understood due to paleomagnetic studies commonly yielding perplexing or conflicting data. Here we report new magnetostratigraphic data from the Ediacaran Ouarzazate Group in the Anti-Atlas Mountains of Morocco, which have primary magnetizations supported by a positive conglomerate test and...

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...

This chapter is dedicated to the Variscan belt segment that is outcropping in NW Africa, covering Morocco, NW Algeria and NW of Mauritania. The NW Africa Variscan belt is considered an intraplate orogen, whose emplacement is largely due to the oceanic clo-sure between Gondwana and Laurentia mainly from Carboniferous to Permian. This chapter re-exam...

The morphology, internal architecture, and emplacement mechanisms of the Central Atlantic Magmatic Province (CAMP) lava flows of the Hartford and Deerfield basins (USA) are presented. The Talcott, Holyoke, and Hampden formations within the Hartford basin constitute distinct basaltic units, each exhibiting chemical, mineralogical, and structural dif...

The morphology, internal architecture, and emplacement mechanisms of the Central Atlantic Magmatic Province (CAMP) lava flows of the Hartford and Deerfield basins (USA) are presented. The Talcott, Holyoke, and Hampden formations within the Hartford basin constitute distinct basaltic units, each exhibiting chemical, mineralogical, and structural dif...

This chapter is dedicated to the Variscan belt segment that is outcropping in NW Africa, covering Morocco, NW Algeria and NW of Mauritania. The NW Africa Variscan belt is considered an intraplate orogen, whose emplacement is largely due to the oceanic closure between Gondwana and Laurentia mainly from Carboniferous to Permian. This chapter reexamin...

Following the Hercynian orogeny, all the continental blocks remained individualized from the Carboniferous to the Triassic periods. The dislocation of the Pangaea occurred in several stages along two major fractures: the Tethyan fracture and the Atlantic fracture. Morocco was, therefore, in a privileged position, and its history since 200 million y...

The accurate textural characterization of mantle xenoliths is one of the fundamental steps to understanding the main processes occurring in the upper mantle, such as sub-solidus recrystallization, magmatic crystallization, and metasomatism. Texture, composition, and mineralogy reflect the temperature, pressure, stress conditions, melting, and/or co...

This chapter is dedicated to the Variscan belt segment that is outcropping in NW Africa, covering Morocco, NW Algeria and NW of Mauritania. The NW Africa Variscan belt is considered an intraplate orogen, whose emplacement is largely due to the oceanic clo-sure between Gondwana and Laurentia mainly from Carboniferous to Permian. This chapter re-exam...

In the eastern and central Anti-Atlas of Morocco, the Late Neoproterozoic Ouarzazate Group (OG) forms a ~ 2 km-thick section of volcano-sedimentary rocks deposited during intermittent magmatic activity, spanning a time period between 590 and 540 Ma. In the eastern Anti-Atlas, the stratigraphy of the OG, termed IMS (Imiter Mine succession), includes...

Along NW Africa, scarce relics of the Alpine Tethys crust are associated with the Maghrebian Flyschs. In the Rif belt, a string of potential relics extends as tectonic slivers within the stacked external nappes from the Beni Malek serpentinite massif to the Bou Adel gabbro massif. These relics define the transported “Mesorif Suture Zone” (MSZ), who...

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 Neoproterozoic Era records the most important geological evolution in the history of the Earth. This era marks a change in the Earth's geodynamic and biosphere, with the second increase in oxygen dissolved in the ocean (Neoproterozoic Oxygenation Event), repeated glacial periods, the appearance of the first multicellular life and the developmen...

During this time, the first complex ecosystems were established in shallow and deep marine environments, and were inhabited by a wide range of macro-organisms known as the Ediacaran biota. The study of the biological aspects of the Ediacaran biota focuses mainly on classic localities (Nama, Newfoundland, Flinders Ranges...), and therefore the searc...

mafic dyke swarms and related igneous associations

The accurate textural characterization of mantle xenoliths is one of the fundamental steps to understanding the main processes occurring in the upper mantle, such as sub-solidus recrystallization, magmatic crystallization, and metasomatism. Texture, composition, and mineralogy reflect the temperature, pressure, stress conditions, melting, and/or co...

The Eastern Anti-Atlas of Morocco hosts an early Ediacaran turbiditic series (Saghro Group) (630–600 Ma) unconformably overlain by thick late Ediacaran (580–550 Ma) terrestrial volcano-clastic formations (Ouarzazate Supergroup), with thin and geographically limited paralic shallow marine sedimentary rocks. This paper presents the first description...

We explore the connections between crustal shortening, volcanism, and mantle dynamics in the Atlas of Morocco. In response to compressional forces and strain localization, this intraplate orogen has evolved far from convergent plate margins. Convective effects, such as lithospheric weakening and plume-related volcanism, contributed in important way...

The Neoproterozoic Era records the most important geological evolution in the history of the Earth. This era marks a change in the geodynamic and biosphere of the Earth marked by the second increase in oxygen dissolved in the ocean (Neoproterozoic Oxygenation Event), repeated glacial periods and the appearance of the first multicellular life and th...

The Ediacaran period records the appearance of the first multicellular and complex organisms in Earth’s history (Knoll et al., 2006; Narbonne et al., 2012). However, the West African Craton (WAC) is commonly regarded as one of the cratons where the Ediacaran biota (metazoans and microfossils) is still poorly documented. Within the West African Crat...

Aeromagnetic airborne represent an effective technique in mapping dike swarms and exploration for carbonatite bodies. Dikes are typically identified as elongated and narrow features with positive magnetic intensity, and carbonatite bodies can produce, in major cases, positive and circular shape magnetic anomalies. In this study, the aeromagnetic su...

Carbonatites, which are significant hosts of economically important rare-earth elements (REE), are challenging to locate as they may crop out as small bodies with indistinct field characteristics. A mapping approach was developed using Landsat 8-OLI and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data to map geological un...

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,...

The Brèche à Micmacca Member at section Le IX in the Lemdad syncline, located in the southern part of the High Atlas in Morocco, contains a diverse range of helcionelloid molluscs, probable polychaetes, and sclerites from other metazoan groups. This collection, consisting of over 3,000 specimens, complements previously described faunal assemblages...

International Dyke Conference (IDC 8) The Eighth International Dyke Conference (IDC8) will concentrate on mafic dyke swarms and related igneous associations, e.g., sills, kimberlites, syenites, carbonatites, volcanics, etc., with a special emphasis on paleogeographic reconstruction based on geological comparison and paleomagnetic studies. The IDC8...

Dyke swarm history of the 850-km-diameter Quetzalpetlatl Corona and feeding of channelized flows from circumferential dykes of interior Boala Corona.

The 900 km long Itoki fluctus formed at least three large lava lakes which may have filled older corona.

Carbonatite-alkaline complexes and their weathering products are the worldwide primary source of strategic resources such as rare earth elements (REE) and igneous phosphates. These commodities are indispensable for many high-technology and industrial applications, which make carbonatite-alkaline complexes important targets for geological exploratio...

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...

Along NW Africa, scarce relics of the Alpine Tethys crust are associated with the Maghrebian Flyschs. In the Rif belt, a string of potential relics extend as tectonic slivers within the stacked external nappes from the Beni Malek massif (serpentinite, metabasalts and Jurassic-Cretaceous marbles) to the Kef-el-Ghar massif (gabbro, magmatic breccia,...

Diverse helcionelloid molluscs, probable polychaetes, and sclerites of other metazoan groups are described from the Brèche à Micmacca Member at section Le IX in the Lemdad syncline in the High Atlas, southern Morocco. The collections include more than 3,000 specimens and complement earlier described faunal assemblages from this interval. The new ma...

Diverse helcionelloid molluscs, probable polychaetes, and sclerites of other metazoan groups are described from the Br` eche a` Micmacca Member at section Le IX in the Lemdad syncline in the High Atlas, southern Morocco. The collections include more than 3,000 specimens and complement earlier described faunal assemblages from this interval. The new...

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 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...

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,...

In the Imiter mine area, the volcano-sedimentary series of the Ouarzazate Group consist mainly of rhyolitic to andesitic porphyritic lavas and their volcanoclastic equivalent. The Imiter Mine sequence (IMS), greater than 1600 m in thickness, is divided into four units. Unit 1 consists of a thick layer of massive conglomerates with well-rounded clas...

Tiout is considered as one of the most visited sections in the world since 1923 and it is also one of the best studied and the most referenced site both regionally and across the western Gondwana (Geyer et al, 1995). It is about 80Km away from Agadir and 20km from Taroudant. It presents a full carbonate platform sequence and outcrop of Cambrian lan...

The Anti-Atlas belt of Morocco preserves exceptional record of an Ediacaran microbial biosphere. The Amane Tazgart Formation of the Ouarzazate Group consist of an Ediacaran volcanic alkaline lake depositional system (ca. 571 Ma) were microbial buildups accreted in an extreme environment. These microbial accumulations are exceptional not only for th...

The famous circular structure of Richat, sometimes referred to as "the eye of Africa", is located in the northwestern part of the Taoudeni basin, in the central part of the Mauritanian Adrar plateaus. It is expressed at the surface as a slightly elliptical depression, about 40 kilometers in diameter, marked by concentric ridges of Proterozoic-Lower...

Spatial and temporal distribution patterns of Precambrian mafic dyke swarms in northern Mauritania (West African craton): analysis and results from remote-sensing interpretation, geographical information systems (GIS), Google Earth ™ images, and regional geology.

Geological mapping of Coronae structures on Venus, the example of Onenhste and adjacent Coronae within the Taussig Quadrangle (V–39).

Lunar and Planetary Science Conference

The famous circular structure of Richat, sometimes referred to as “the eye of Africa”, is located in the northwestern part of the Taoudeni basin, in the central part of the Mauritanian Adrar plateaus. It is expressed at the surface as a slightly elliptical depression, about 40 km in diameter, marked by concentric ridges of Proterozoic-Lower Paleozo...

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 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 mainly m...

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...

Investigating the texture and chemistry of mantle xenoliths allow us to constrain the nature of the upper mantle, the mechanism that generate melts and the evolution of the lithosphere beneath regions where no samples were exposed by tectonic activity. Texture, as well as chemical composition and mineralogical paragenesis, reflects the temperature,...

Mapping of carbonatites and related mineral deposits has occupied prominent place in mineral resource exploration programs given their potential to host valuable concentrations of critical metals such as rare earth elements and niobium. Based on spectral characteristics of most indicative minerals for these rocks, a mapping approach was developed u...

Mapping of carbonatites and related mineral deposits has occupied prominent place in mineral resource exploration programs given their potential to host valuable concentrations of critical metals such as rare earth elements and niobium. Based on spectral characteristics of most indicative minerals for these rocks, a mapping approach was developed u...

Mapping of carbonatites and related mineral deposits has occupied prominent place in mineral resource exploration programs given their potential to host valuable concentrations of critical metals such as rare earth elements and niobium. Based on spectral characteristics of most indicative minerals for these rocks, a mapping approach was developed u...

Emerging evidence suggests widespread ferruginous marine conditions promoted global seawater phosphate depletion and the maintenance of a low oxygen world at the start of the Neoproterozoic Era. However, the large-scale deposition of marine sedimentary Fe formations, as observed in the Paleoproterozoic, is rare in the early Neoproterozoic Era. We s...