André Michard

André Michard
Université Paris-Sud 11 | Paris 11 · Départment Sciences de la Terre

a.e. ENS, Agrégé Univ., Dr es Sci.

About

255
Publications
331,939
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8,310
Citations
Additional affiliations
October 1987 - March 1999
Université Paris-Sud 11
Position
  • Professor (Full)
Description
  • Teaching at Paris-Sud, and research at Ecole Normale Supérieure, Laboratoire de Géologie
October 1984 - September 2000
Ecole Normale Supérieure de Paris
Position
  • Research Associate
Description
  • Research in the Alps and Morocco

Publications

Publications (255)
Article
Full-text available
Here we describe the structure, the high-pressure, low-temperature (HP-LT) metamorphism and tectonic evolution of the Briançonnais distal margin units from the south Western Alps. The studied area extends southwest of the Dora-Maira (U)HP basement units and east-southeast of the classical Briançonnais nappes. A new structural map accompanied by geo...
Article
Full-text available
Here we describe the structure, the high-pressure, low-temperature (HP-LT) metamorphism and tectonic evolution of the Briançonnais distal margin units from the south Western Alps. The studied area extends southwest of the Dora-Maira (U)HP basement units and east-southeast of the classical Briançonnais nappes. A new structural map accompanied by geo...
Conference Paper
Full-text available
L'arc de Gibraltar est célèbre pour ses péridotites subcontinentales qui s'étendent largement en Espagne (Ronda) et au Maroc (Beni Bousera). Le calendrier et les processus de l'exhumation de ces roches mantelliques font encore l'objet de controverses. Nous contribuons à ce débat à travers une étude multi-échelle et pluridisciplinaire sur des marbre...
Chapter
The exhumation of the Beni Bousera peridotites of the Internal Rif is currently ascribed to the Neogene tectonics of the Alboran Domain. Here we report on marbles included in a fault zone surrounding the Beni Bousera peridotite-granulite unit and overlain by the Filali gneiss and schists. They should derive from a sedimentary cap overlying unconfor...
Chapter
Full-text available
The Western Moroccan Meseta exposes in the Zaian region a pre-Visean, Eo-Variscan belt of inclined to recumbent folds detached from their Precambrian basement and embedded in the Variscan Orogen. Using the Raman Spectroscopy of Carbonaceous Material (RSCM) method, we obtained the first quantitative thermometric characterization of the Cambro-Ordovi...
Poster
Full-text available
The Gibraltar arc is famous for its subcontinental peridotites that extend widely in Spain (Ronda) and Morocco (Beni Bousera). The timing and processes of the exhumation of these mantle rocks are still a matter of controversy. We contribute to this debate through a multi-scale and multidisciplinary study of high-grade marbles outcropping around the...
Conference Paper
Full-text available
The Gibraltar Arc is famous for its subcontinental peridotites that extend widely in Spain (Ronda) and Morocco (Beni Bousera). The age of exhumation of these mantle rocks is considered either basically as syn-orogenic (Alpine) or partly pre-orogenic. Here we report on marbles that crop out on top of the granulitic envelope (kinzigites) of the Beni...
Article
Two samples of a granodiorite and a hypersthene granodiorite provided a unique opportunity to investigate the nature of the basement of the Mazagan Escarpment, the northwestern margin of continental Africa (Morocco) on a steep part of the lower continental slope in offshore Morocco. We conducted U–Pb LA-ICPMS geochronology on zircon from the granod...
Conference Paper
Full-text available
The West Mediterranean Alpine belts of the Rif and its northern counterpart, the Betics, are famous for the subcontinental peridotites exposed in their Internal zones (Alboran Domain), the Beni Bousera (BB) and Ronda massifs, respectively. The Beni Bousera Marbles (BBMs) here described are known for long in the northern Rif, but remained overlooked...
Article
Full-text available
The timing and process of exhumation of the subcontinental peridotites of the Gibraltar Arc (Ronda, Beni Bousera) have been discussed extensively over the last decades. In this work, we contribute to this debate through the first mapping, structural and petrological analyses, and SHRIMP U-Th-Pb dating of high-grade marbles that crop out around the...
Conference Paper
Full-text available
The Rif belt forms the westernmost segment of the Maghrebides and the southern branch of the Gibraltar Arc, whereas the Betic Cordilleras make up the northern branch. This orocline extends in a complex area of triple junction between the Central Atlantic and the two branches of the westernmost Tethys, i.e., the E-NE trending Ligurian-Maghrebian Tet...
Poster
Full-text available
The Rif belt forms the westernmost segment of the Maghrebides and the southern branch of the Gibraltar Arc, whereas the Betic Cordilleras make up the northern branch. This orocline extends in a complex area of triple junction between the Central Atlantic and the two branches of the westernmost Tethys, i.e., the E-NE trending Ligurian-Maghrebian Tet...
Article
Full-text available
Key Points The main Mesorif gabbros emplaced in a Liassic oceanic domain and do not belong to the Central Atlantic Magmatic Province (CAMP) CAMP dolerites may occur separately next to the oceanic gabbros in the structurally complex Mesorif zone The prerift/synrift cover of the distal margin could have emplaced by gravity sliding onto the Mesorif oc...
Article
The thermal structure inherited from the high-temperature rifting phase may control the deformation regime during the first phase of compression. The Zaian Mts of Western Meseta provide a nice example studied here with the help of the Raman method.
Article
Numerous mafic dykes, sills and laccoliths crop out in the southern part of the Tafilalt basin (Eastern Anti-Atlas, Morocco). These rocks intrude the mildly folded Ordovician to Early Carboniferous formations, consisting mainly of lamprophyric dolerites and camptonites with minor gabbros and syenodiorites. Previous geochemical studies have shown th...
Article
Full-text available
The thermal structure inherited from the high-temperature rifting phase may control the deformation regime during the first phase of compression. The Zaian Mountains and adjoining Jebel Hadid constitute a demonstrative case study in the southern branch of the Variscan belt in Central Meseta, Morocco. There the thick, Cambrian-Ordovician quartzite s...
Article
Full-text available
Between the High Atlas and the Saharan platform, the Anti-Atlas of Morocco offers large exposures of Precambrian rocks beneath the moderately folded Paleozoic series. These inliers allow reconstructing a segment of the Pan-African Belt and of its foreland at the northern outskirts of the West African Craton (WAC). From ∼ 885 Ma to ∼ 540 Ma, three p...
Article
Full-text available
This work concerns the northernmost limit of the West African Craton (WAC) and Variscan WAC-related terranes of NW Africa. Based on newly obtained radiometric age of an oceanic gabbro from the ‘‘Mesorif Suture Zone’’ of the External Rif Belt, we propose a revised interpretation of this puzzling lineament. We report on a 190 � 2 Ma LA–ICP–MS U–Pb zi...
Article
Full-text available
Based on the Mesozoic-Cenozoic stratigraphy of the 10 nappes that define the Briançonnais domain in the Ubaye transect of the Western Alps, we restore the distal portion of the (hyper-) extended European margin during the Late Jurassic.
Article
Full-text available
Located in the southern Subalpine Chains, the Dévoluy-Bochaine (D-B) area displays an "ante-Senonian" (Turonian) unconformity classically interpreted as the result of a compressional event. We argue that the D-B uncon-formity results from a major synsedimentary collapse on the slope of the European paleomargin. During the Tithonian-Late Cretaceous...
Conference Paper
Full-text available
Deformation in the External Subalpine fold-thrust belt
Article
Most of the structural studies of the intracontinental High Atlas belt of Morocco have dealt with the central part of the belt, whose basement does not crop out. Here we study the Alpine deformation of the North Subatlas Zone, which is the part of the Western High Atlas (WHA) Paleozoic Massif that involves both Paleozoic basement units and remnants...
Book
Full-text available
La feuille d’Imi-N-Tanout de la carte géologique du Maroc au 1/50.000 est située à l’extrémité occidentale du Massif ancien du Haut Atlas occidental. Elle est séparée du Haut Atlas de Marrakech, d’ouest en est, par les feuilles d’Addouz, Azegour et Amezmiz du présent programme de cartographie géologique. La feuille d’Imi-N-Tanout présente trois dom...
Book
Full-text available
ABSTRACT Abstract The Amezmiz sheet of the geological map of Morocco 1:50 000 is located in the eastern part of the western High Atlas, at its join to the Marrakech Atlas. It offers three contrasting morphological areas, with, i) in the south, a young mountainous domain corresponding to the axis of the Atlas chain, deeply cut by the Agoundis and Nf...
Poster
Full-text available
The northern margin of the West African Craton is a mobile zone affected by numerous geodynamic episodes: Pan-African, Variscan and Alpine orogenies. These orogenic phenomena dominantly horizontal are followed by more discret vertical movements, the restitution of which is often problematic. The Anti-Atlas Belt occupies a critical position at the n...
Article
Full-text available
The Saghro Group (SG) is a folded, low-grade volcano-sedimentary series up to 8 km thick that crops out within and to the north of the Pan-African suture zone in the central and eastern Anti-Atlas. Here we describe the SG of the Ougnat inliers that are exposed in the easternmost Anti-Atlas beneath the unconformable, Late Ediacaran Ouarzazate Group...
Article
Full-text available
The present research provides the first evidence of invertebrate activity assigned to the ichnogenus Selenichnites occurring together with moderately diverse ichnofossils from the middle to late Cambrian of the Moroccan Meseta. The invertebrate traces occur in sandstone strata of the El Hank Formation within the Imfout Syncline, in the northern par...
Research
Full-text available
A new edition of the Geological Map of Africa at the 1:10 million scale was published on the occasion of the 35th International Geological Congress (Cape Town, 29 August-2 September 2016) under the direction of the Commission of the Geological Map of the World, with support from UNESCO and the Geological Society of Africa, and the technical and sci...
Conference Paper
Full-text available
The West African Craton (WAC) extends in the Saharan regions of southernmost Morocco. The WAC crystalline basement crops out in the Reguibat Shield or Arch, whereas it is hidden beneath Mesoproterozoic to Cenozoic undeformed sediments in the Tindouf, Reggane and Taoudenni basins to the north, east and south of the arch, respectively. To the west, i...
Article
Full-text available
The transition from the Cambrian to Ordovician in Morocco is known to be characterized by a frequent Furongian hiatus, restricted extension of the Tremadocian marine deposits, and frequent unconformities at the base of the transgressive upper Floian deposits. In the present work, we first highlight the occurrence of Fe- and mica-rich, red silty/san...
Article
Conflicting views are expressed in literature concerning fold interference patterns in thick-skinned tectonic context (e.g. Central Anti-Atlas and Rocky Mountains-Colorado areas). Such patterns are referred to superimposed events with distinct orientation of compression or to the inversion of paleofaults with distinct strike during a single compres...
Article
Conflicting views are expressed in literature concerning fold interference patterns in thick-skinned tectonic context (e.g. Central Anti-Atlas and Rocky Mountains-Colorado areas). Such patterns are referred to superimposed events with distinct orientation of compression or to the inversion of paleofaults with distinct strike during a single compres...
Article
The Raman Spectroscopy of Carbonaceous Materials (RSCM) geothermometry approach allows determining the peak temperature recorded by metasediments through their metamorphic history. This technique, however, has been calibrated using Meso-Cenozoic metapelitic rocks that underwent a single metamorphic cycle. Until now, the reliability of the RSCM meth...
Article
Full-text available
Mesozoic strata of North Africa yield the first occurrence of the ichnogenus Selenichnites.The trace fossils occur on the top surface of a sandy carbonate deposit in the axis ofa Middle Atlas syncline (Skoura Syncline, NE Morocco). The ichnofossil-bearing horizonbelongs to the Late Bajocian–Early Bathonian Ich Timellaline/Bou Akrabene Formation.The...
Conference Paper
Full-text available
The present research provides the first evidence of invertebrate activities attributed to the ichnogenus Selenichnites from the Middle Cambrian of Moroccan Meseta. The invertebrate traces occur in sandstone strata from the El Hank Formation of the Imfout syncline, in the northern part of the Rehamna Massif (Coastal Block, Western Moroccan Meseta)....
Article
Full-text available
The serpentinization of the harzburgitic mantle section of the Bou Azzer Neoproterozoic ophiolite is studied by field mapping, structural observations, optical micrography, SEM and X-ray diffractometry, and relationships with Co, Ni, Cr and sulphides minerals are discussed. Serpentinization occurred in two major steps with, i) intra-oceanic pseudom...
Article
Full-text available
West of the southern, Archean, part of the Reguibat Rise of the West African Craton the Oulad Dlim Massif consists of metamorphic nappes stacked during the Mauritanides (Variscan) orogeny. In the Derraman region, about 12km west of the nappes, we have found strongly deformed hypersolvus aegirine-riebeckite A1-type granites with SHRIMP zircon U-Pb a...
Article
Full-text available
This research provides the first evidence of invertebrate biogenic sedimentary structures attributed to the ichnogenus Selenichnites from the Jurassic of Morocco. The ichnofossils occur in calcareous strata from the
Conference Paper
Full-text available
The remote regions of Southern Morocco are rich in outstanding geological landscapes and outcrops not well known by the general public. In this work, we propose a200 km long, southeast-trending geotrail starting from the Dakhla sea-resort and ending at Awsard inside the Sahara Desert, with a total of ten geosites of particular interest for geotouri...
Poster
Full-text available
La topographie de l’Afrique du Nord est marquée en domaine intraplaque par des bombements topographiques importants, associés à du magmatisme cénozoïque. Le massif du Siroua dans l’Anti-Atlas central, est l’un de ces bombements. Il est constitué d’un socle précambrien structuré par l’orogénèse panafricaine et culminant à plus de 3300 m d’altitude (...
Conference Paper
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Presentation of the Paleozoic sedimentation on the NW margin of Gondwana with emphasis on its geodynamic framework and on the Anti-Atlas Basin.
Conference Paper
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This is short course for undergraduate students. A commentary of each diapositive is to be found in the other title: Géologie du Rif, Marrakech 2015, texte.
Conference Paper
Full-text available
Short course for undergraduate students. Explanation (in French) of each diapositive can be found in a separate file (see dataset, Géologie du Rif, Marrakech 2015, texte)
Conference Paper
Full-text available
This text (in French) corresponds to the commentary of the presentation with the same title and date.
Article
Full-text available
The remote regions of Southern Morocco are rich in outstanding geological landscapes and outcrops not well known to the general public. In this paper, we propose two east-trending geotrails (transverse to the regional trend of the structures) with a total of 19 geosites of particular interest for geotourists as well as for geologists. The southernm...
Article
Full-text available
The serpentinization of the harzburgitic mantle section of the Bou Azzer Neoproterozoic ophiolite is studied by field mapping, structural observations, optical micrography, SEM and X-ray diffractometry, and relationships with Co, Ni, Cr and sulphides minerals are discussed. Serpentinization occurred in two major steps with, i) intra-oceanic pseudom...
Article
Full-text available
The post-Pan-African evolution of the northern border of the West African Craton is largely controlled by the remobilisation of Late Neoproterozoic basement faults. The Upper Ediacaran volcanic and volcano-sedimentary sequences of the Ouarzazate Group show dramatic and rapid thickness changes, consistent with active extensional faulting associated...