WorldCat Identities

Moyen, Jean-François

Overview
Works: 19 works in 51 publications in 3 languages and 485 library holdings
Genres: Textbooks  History  Academic theses 
Roles: Editor, Contributor, Cartographer, Other, htt, Author, Thesis advisor, Publishing director, Opponent
Publication Timeline
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Most widely held works by Jean-François Moyen
Geochemical modelling of igneous processes - principles and recipes in R language : bringing the power of R to a geochemical community by V Janoušek( )

22 editions published between 2015 and 2016 in 3 languages and held by 300 WorldCat member libraries worldwide

"The aim of this book is to unlock the power of the freeware R language to advanced university students and researchers dealing with whole-rock geochemistry of (meta-) igneous rocks. The first part covers data input/output, calculation of commonly used indexes and plotting in R. The core of the book then focusses on the presentation and practical implementations of modelling techniques used for fingerprinting processes such as partial melting, fractional crystallization, binary mixing or AFC using major-, trace-element and radiogenic isotope data. The reader will be given a firm theoretical basis for forward/reverse modelling, followed by exercises dealing with typical problems likely to be encountered in real life, and their solutions using R. The concluding sections demonstrate, using practical examples, how a researcher can proceed in developing a realistic model simulating natural systems. The appendices outline the fundamentals of the R language and provide a quick introduction to the open-source R-package GCDkit for Interpretation of whole-rock geochemical data from igneous and metamorphic rocks"- - Springer
Magmatisme et roches magmatiques by Bernard Bonin( Book )

3 editions published in 2011 in French and held by 124 WorldCat member libraries worldwide

Archean ganitoids of India : windows into early Earth tectonics / edited by S. Dey and J.-F. Moyen by S Dey( Book )

8 editions published in 2020 in English and held by 31 WorldCat member libraries worldwide

"Granitoids form the bulk of the Archean continental crust and preserve key information on early Earth evolution. India hosts five main Archean cratonic blocks (Aravalli, Bundelkhand, Singhbhum, Bastar and Dharwar). This book summarizes the available information on Archean granitoids of Indian cratons. The chapters cover a broad spectrum of themes related to granitoid typology, emplacement mechanism, petrogenesis, phase-equilibria modelling, temporal distribution, tectonic setting, and their roles in fluid evolution, metal delivery and mineralizations. The book presents a broader picture incorporating regional- to craton-scale comparisons, implications for Archean geodynamic processes, and temporal changes thereof. This synthesis work, integrating modern concepts on granite petrology and crustal evolution, offers an irreplaceable body of reference information for any geologist interested in Archean Indian granitoids."--
Carte géologique de la France à 1/50/000 by François Prognon( )

1 edition published in 2012 in French and held by 11 WorldCat member libraries worldwide

Le magmatisme granitique à la transition archéen-protérozoïque : exemple du craton de Dharwar, Inde du sud (granite de Closepet et intrusions associées) by Jean-François Moyen( Book )

3 editions published between 2000 and 2006 in French and held by 3 WorldCat member libraries worldwide

LA FIN DE L'ARCHEEN EST GENERALEMENT MARQUEE PAR UNE PERIODE D'INTENSE ACTIVITE MAGMATIQUE (MISE EN PLACE DE GRANITOIDES). CES GRANITES DIFFERENT A LA FOIS DES TTG ARCHEENNES, ET DES GRANITES CALCO-ALCALINS MODERNES. LE CRATON DE DHARWAR, EN INDE DU SUD, PRESENTE A L'AFFLEUREMENT DE NOMBREUX MASSIFS GRANITIQUES TARDI-ARCHEENS. DE PLUS, IL OFFRE UNE COUPE NATURELLE DE LA CROUTE CONTINENTALE, DEPUIS DES NIVEAUX PROFONDS (FACIES GRANULITE), JUSQU'A DES NIVEAUX SUPERFICIELS (FACIES SCHISTE VERT). L'UN DE CES GRANITES, LE MASSIF DE CLOSEPET, AFFLEURE A TOUT LES NIVEAUX STRUCTURAUX. UNE ETUDE MULTI-METHODOLOGIQUE (TERRAIN, SPOT, ASM) DU CHAMP DE DEFORMATION DANS ET AUX ALENTOURS DE CE MASSIF A PERMIS DE PROPOSER UN MODELE DE MISE EN PLACE DE CES MAGMAS AU SEIN DE ZONES DE CISAILLEMENT ACTIVES. LA MODELISATION GEOCHIMIQUE A PERMIS DE DEMONTRER QUE CE GRANITE EST LE PRODUIT DU MELANGE DE DEUX MAGMAS, L'UN ISSU DE LA FUSION PARTIELLE D'UN MANTEAU METASOMATISE PAR DES MAGMAS ISSUS DE LA FUSION D'UNE PLAQUE SUBDUCTEE ; L'AUTRE ISSU DE LA FUSION PARTIELLE DU SOCLE GNEISSIQUE, RECHAUFFE PAR L'ARRIVEE DES MAGMAS MANTELLIQUES. DANS LE CRATON, ON TROUVE PLUSIEURS TYPES DE GRANITES TARDI-ARCHEENS. DES MAGMAS DE TYPE TTG (FUSION D'UNE PLAQUE BASALTIQUE SUBDUCTEE) COHABITENT AVEC DES MAGMAS DE TYPE SANUKITOIDE (INTERACTION DE MAGMAS TTG AVEC LES PERIDOTITES DU MANTEAU), DES GRANITES ANATECTIQUES, ET DE GRANITES DU TYPE CLOSEPET . LES MEMES TYPES DE GRANITES EXISTENT DANS TOUT LES CRATONS ARCHEENS. CECI AMENE A PROPOSER UN MODELE D'EVOLUTION GEODYNAMIQUE POUR L'ARCHEEN : CHAQUE CRATON AURAIT CONNU UNE SUCCESSION DE CYCLES D'ACTIVITES COMMENCANT PAR UN COLLAGE D'ARC INSULAIRES (TTG ET SANUKITOIDES, ET CHEVAUCHEMENTS), PUIS UN REMANIEMENT HT-BP DU CONTINENT NEOFORME, AVEC REFUSION DU MANTEAU ENRICHI (GRANITES TYPE CLOSEPET ET STRUCTURES EN DOMES ET BASSINS). LE REFROIDISSEMENT PROGRESSIF DE LA TERRE AU COURS DE L'ARCHEEN A RENDU LES INTERACTIONS ENTRE LES MAGMAS TTG ET LE MANTEAU DE PLUS EN PLUS IMPORTANTES, CE QUI SE TRADUIT PAR UNE ABONDANCE CROISSANTE DES SANUKITOIDES ET DES GRANITES TYPE CLOSEPET. FINALEMENT, AU PROTEROZOIQUE, LA TERRE EST DEVENUE ASSEZ FROIDE POUR EMPECHER LA FUSION DE LA PLAQUE PLONGEANTE, CAUSANT DONC UNE TRANSITION VERS DES MECANISMES PETROGENETIQUES RADICALEMENT DIFFERENTS
Plutons and domes: the consequences of anatectic magma extraction--example from the southeastern French Massif Central by A Villaros( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Protracted, coeval crust and mantle melting during Variscan late-orogenic evolution: U-Pb dating in the eastern French Massif Central by Oscar Laurent( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Insights into the complexity of crustal differentiation: K2O-poor leucosomes within metasedimentary migmatites from the Southern Marginal Zone of the Limpopo Belt, South Africa( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

Abstract: Differentiation of the continental crust is the result of complex interactions between a large number of processes, which govern partial melting of the deep crust, magma formation and segregation, and magma ascent to significantly higher crustal levels. The anatectic metasedimentary rocks exposed in the Southern Marginal Zone of the Limpopo Belt represent an unusually well-exposed natural laboratory where the portion of these processes that operate in the deep crust can be directly investigated in the field. The formation of these migmatites occurred via absent incongruent melting reactions involving biotite, which produced cm- to m-scale, K2 O-poor garnet-bearing stromatic leucosomes, with high Ca/Na ratios relative to their source rocks. Field investigation combined with geochemical analyses, and phase equilibrium modelling designed to investigate some aspects of disequilibrium partial melting show that the outcrop features and compositions of the leucosomes suggest several steps in their evolution: (1) Melting of a portion of the source, with restricted plagioclase availability due to kinetic controls, to produce a magma (melt + entrained peritectic minerals in variable proportions relative to melt); (2) Segregation of the magma at near peak metamorphic conditions into melt accumulation sites (MAS), also known as future leucosome; (3a) Re-equilibration of the magma with a portion of the bounding mafic residuum via chemical diffusion (H2 O, K2 O), which triggers the co-precipitation of quartz and plagioclase in the MAS; (3b) Extraction of melt-dominated magma to higher crustal levels, leaving peritectic minerals entrained from the site of the melting reaction, and the minerals precipitated in the MASs to form the leucosome in the source. The key mechanism controlling this behaviour is the kinetically induced restriction of the amount of plagioclase available to the melting reaction. This results in elevated melt H2 O and K2 O and chemical potential gradient for these components across the leucosome/mafic residuum contact. The combination of all of these processes accurately explains the composition of the K2 O-poor leucosomes. These findings have important implications for our understanding of melt segregation in the lower crust and minimum melt residency time which, according to the chemical modelling, is <5 years. We demonstrate that in some migmatitic granulites, the leucosomes constitute a type of felsic refractory residuum, rather than evidence of failed magma extraction. This provides a new insight into the ways that source heterogeneity may control anatexis
The processes that control leucosome compositions in metasedimentary granulites: perspectives from the Southern Marginal Zone migmatites, Limpopo Belt, South Africa( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

Abstract Anatexis of metapelitic rocks at the Bandelierkop Quarry (BQ) locality in the Southern Marginal Zone of the Limpopo Belt occurred via muscovite and biotite breakdown reactions which, in order of increasing temperature, can be modelled as: (1) Muscovite + quartz + plagioclase = sillimanite + melt; (2) Biotite + sillimanite + quartz + plagioclase = garnet + melt; (3) Biotite + quartz + plagioclase = orthopyroxene ± cordierite ± garnet + melt. Reactions 1 and 2 produced stromatic leucosomes, which underwent solid-state deformation before the formation of undeformed nebulitic leucosomes by reaction 3. The zircon U-Pb ages for both leucosomes are within error identical. Thus, the melt or magma formed by the first two reactions segregated and formed mechanically solid stromatic veins whilst temperature was increasing. As might be predicted from the deformational history and sequence of melting reactions, the compositions of the stromatic leucosomes depart markedly from those of melts from metapelitic sources. Despite having similar Si contents to melts, the leucosomes are strongly K-depleted, have Ca:Na ratios similar to the residua from which their magmas segregated and are characterized by a strong positive Eu anomaly, whilst the associated residua has no pronounced Eu anomaly. In addition, within the leucosomes and their wall rocks, peritectic garnet and orthopyroxene are very well preserved. This collective evidence suggests that melt loss from the stromatic leucosome structures whilst the rocks were still undergoing heating is the dominant process that shaped the chemistry of these leucosomes and produced solid leucosomes. Two alternative scenarios are evaluated as generalized petrogenetic models for producing Si-rich, yet markedly K-depleted and Ca-enriched leucosomes from metapelitic sources. The first process involves the mechanical concentration of entrained peritectic plagioclase and garnet in the leucosomes. In this scenario, the volume of quartz in the leucosome must reflect the remaining melt fraction with resultant positive correlation between Si and K in the leucosomes. No such correlation exists in the BQ leucosomes and in similar leucosomes from elsewhere. Consequently, we suggest disequilibrium congruent melting of plagioclase in the source and consequential crystallization of peritectic plagioclase in the melt transfer and accumulation structures rather than at the sites of biotite melting. This induces co-precipitation of quartz in the structures by increasing SiO2 content of the melt. This process is characterized by an absence of plagioclase-induced fractionation of Eu on melting, and the formation of Eu-enriched, quartz + plagioclase + garnet leucosomes. From these findings, we argue that melt leaves the source rapidly and that the leucosomes form incrementally as melt or magma leaving the source dumps its disequilibrium Ca load, as well as quartz and entrained ferromagnesian peritectic minerals, in sites of magma accumulation and escape. This is consistent with evidence from S-type granites suggesting rapid magma transfer from source to high level plutons. These findings also suggest that leucosomes of this type should be regarded as constituting part of the residuum from partial melting
Rapid evolution from sediment to anatectic granulite in an Archean continental collision zone: the example of the Bandelierkop Formation metapelites, South Marginal Zone, Limpopo Belt, South Africa( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

Abstract The metamorphic history of the Southern Marginal Zone (SMZ) of the Limpopo Belt, South Africa, possibly provides insight into one of the oldest preserved continental collision zones. The SMZ consists of granitoid gneisses (the Baviaanskloof Gneiss) and subordinate, infolded metasedimentary, metamafic and meta-ultramafic lithologies (the Bandelierkop Formation) and is regarded as the c. 2700 Ma granulite facies reworked equivalent of the Kaapvaal craton basement. The granulite facies metamorphism is proposed to have occurred in response to collision between the Kaapvaal and Zimbabwe cratons. Previous studies have proposed a wide variety of P-T loops for the granulites, with considerable discrepancy in both the shapes of the retrograde paths and the magnitude of the peak P-T conditions. To date, the form of the prograde path and the timing of the onset of metamorphism remain unknown. This study has used a range of different metasedimentary rocks from a large migmatitic quarry outcrop to better constrain the metamorphic history and the timing of metamorphism in the SMZ. Detrital zircon ages reveal that the protoliths to the metasedimentary rocks were deposited subsequent to 2733 ± 13 Ma. Peak metamorphic conditions of 852.5 ± 7.5 °C and 11.1 ± 1.3 kbar were attained at 2713 ± 8 Ma. The clockwise P-T path is characterized by heating in the sillimanite field along a P-T trajectory which approximately parallels the kyanite to sillimanite transition, followed by near-isothermal decompression at peak temperature and near-isobaric cooling at ~6.0 kbar. These results support several important conclusions. First, the sedimentary rocks from the Bandelierkop Formation are not the equivalent of any of the greenstone belt sedimentary successions on the Kaapvaal craton, as has been previously proposed. Rather, they post-date the formation of the Dominion and Witwatersrand successions on the Kaapvaal craton. From the age distribution of detrital zircon, they appear to have received significant input from various origins. Consequently, at c. 2730 Ma, the Baviaanskloof Gneiss most likely acted as basement onto which the sedimentary succession represented by the Bandelierkop Formation metapelites was deposited. Second, the rocks of the SMZ underwent rapid evolution from sediment to granulite facies anatexis, with a burial rate of ~0.17 cm yr−1. Peak metamorphism was followed by an isothermal decompression to 787.5 ± 32.5 °C and 6.7 ± 0.5 kbar and isobaric cooling to amphibolite facies conditions, below 640 °C prior to 2680 ± 6 Ma. This age for the end of the high-grade metamorphic event is marked by the intrusion of crosscutting, undeformed pegmatites that are within error the same age as the crosscutting Matok intrusion (2686 ± 7 Ma). Collectively, the burial rate of the sedimentary rocks, the shape of the P-T path, the burial of the rocks to in excess of 30 km depth and the post-peak metamorphic rapid decompression argue strongly that the SMZ contains sediments deposited along an active margin during lateral convergence, and that the SMZ was metamorphosed as a consequence of continental collision along the northern margin of the Kaapvaal craton at c. 2700 Ma
Evolution of the continental crust and significance of the zircon record, a case study from the French Massif Central by Simon Couzinié( )

1 edition published in 2017 in English and held by 1 WorldCat member library worldwide

The formation of the continental crust is a major consequence of Earth differentiation. Understanding how the crust formed and evolved through time is paramount to locate the vast mineral deposits hosted therein and address its influence on the global climate, ultimately affecting the development of terrestrial life. Recent advances on the topic of continental crust evolution benefited from improvements of analytical techniques enabling in situ measurements of U-Pb- Hf-O isotope compositions in zircon, a widespread accessory mineral of continental igneous rocks. The time constrains derived from the U-Pb chronometer coupled with the petrogenetic information retrieved from Hf-O isotope signatures are currently used to unravel the diversity and succession of magmatic events affecting the continental crust at the regional and global scales. This study reconstructs the evolutionary path followed by the crust segment today exposed in the eastern part of the French Massif Central (FMC), a portion of the Variscan belt of Western Europe, with the aim to investigate the potential flaws of the zircon record of crust evolution. In this scope, the origin and geodynamic significance of the constituent FMC lithological units are tackled by combining conventional petrological observations with zircon U-Pb-Hf-O isotope data. The results obtained following this integrated approach are then confronted to the conclusions that would have been drawn solely from zircon isotopic signatures, taken out of their petrological context, as is commonly performed in studies investigating crust evolution. The oldest rocks of the FMC correspond to Ediacaran (590_550 Ma) meta-sediments deposited in back-arc basins along the northern Gondwana margin. Such basins were fed by a mixed detritus originating from the adjacent Cadomian magmatic arc and a distal Gondwana source, presumably the Sahara Metacraton. Partial melting of these meta-sediments at the Ediacaran/Cambrian boundary led to voluminous S-type granitic magmatism, pinpointing a first major crust reworking event in the FMC. The origin of anatexis likely stems from the transient thickening of the hot, back-arc crust caused by the flattening of the Cadomian subduction. Subordinate melting of the depleted backarc mantle at that time is also documented. During the Lower Paleozoic, rifting of the northern Gondwana provoked coeval crust and (limited) mantle melting. Mantle-derived igneous rocks show markedly diverse trace element and isotopic signatures, consistent with a very heterogeneous mantle source pervasively modi_ed by the Cadomian subduction. Finally, the Variscan collision resulted in crustal melting as evidenced by the emplacement of S-type granites and the formation of migmatite domes, the spatial distribution of which being partly controlled by the crustal architecture inherited from pre-orogenic events. Synchronous intrusion of mafic mantle-derived magmas and their differentiates testify for Variscan post-collisional new continental crust production in the FMC. Two major inconsistencies exist between these results and the zircon record. First, zircon Hf model ages would point to substantial Mesoproterozoic crust formation in the FMC whereas more than 60% of the crust is actually Neoproterozoic in age. Second, new additions to the continental crust volume during the Variscan orogeny are not recorded even though 5 to 10% of the exposed crust formed at that time. The origin of both discrepancies inherently lies in the mixed isotopic signature carried by many zircon grains. Such equivocal information can only be detected when additional petrological constrains on the zircon host rocks are available and provide guidance in interpreting the zircon record of crust evolution
The metamorphic and anatectic history of Archaean metapelitic granulites from the South Marginal Zone, Limpopo Belt, South Africa by Gautier Nicoli( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

Anatexis is the first step in granite genesis. Partial melting in the lower crust may produce leucoratic features of unusual chemical compositions, very different from the final products of crustal differentiation. Therefore, the links that exists between some migmatites and crustal-derived granites can be ambiguous. This study is an investigation of the anatectic history of a high-grade terrain: the Southern Marginal Zone of the Limpopo Belt (SMZ), north to the Kaapvaal Craton in South Africa. The work involved an integrated field, metamorphic, geochemical and geochronogical study of the metasedimentary granulites from two separate quarries in the northern zone of the Southern Marginal Zone, the Bandelierkop quarry and the Brakspruit quarry, where Neoarchean high-grade partial melting features can be observed. The project has aimed to address two main issues: (1) to accurately constrain the pressure temperature conditions and the age of the metamorphic episode in the SMZ, with implication for the geodynamic processes near the end of the Archean, (2) to investigate the fluid-absent partial melting reactions that control formation of K2O-poor leucosomes and to understand the chemical relationships in the system source-leucosome-melt-S-type granite. The P-T-t record retained in the Bandelierkop Formation metapelites, constrained by phase equilibria modelling as well as zircon LA-ICP-MS geochronology, gives an insight into crustal differentiation processes in the lower crust. Rocks in both quarries indicate high-temperature metamorphism episodes with peak conditions of 840-860 oC and 9-11 kbar at c. 2.71 Ga with formation of leucosomes (L1) during the prograde path. Minor leucocratic features (L2) were produced during decompression to 6-7 kbar. The end of the metamorphic event is marked by the granulites/amphibolites facies transition (< 640 oC) at c. 2.68 Ga. The maximum deposit age for the detrital zircons in the metapelites (c. 2.73 Ga) indicates a rapid burial process ( 0.17 cm.y-1). Those evidences strongly support that the Southern Marginal Zone contains sediments deposited in an active margin during convergence, and that the metapelites were metamorphosed and partially melted as a consequence of continental collision along the northern margin of the Kaapvaal Craton at c. 2.7 Ga. The leucocratic features generated along this P-T-t path display an unusual chemistry with low K2O and FeO+MgO content and high CaO content. The combination of field observations, chemical mapping and geochemical analyses leads to the conclusion the major part of the leucosomes (L1) crystallized prior to syn-peak of metamorphism concurrent with melt extraction from the source. This study documents the details of leucosomes formation using field observations in the Southern Marginal Zone and numerical modelling. This work demonstrates that the formation of K2O-poor leucosome in the metasedimentary lower crust is controlled by the difference in volume of equilibration and heterogeneities within the migmatites. The partial melting of the source coupled with melt loss and water diffusivity within the melt transfer site is a potential mechanism to explain the chemical link in the system residuum-melt-S-type granite
Etude géochronologique U-Pb et isotopique Lu-Hf sur zircon du groupe de Turee Creek : implications sur l'événement de grande oxygénation et les glaciations paléoprotérozoïques by Tom Caquineau( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

The Archean - Proterozoic transition at 2.45 Ga is marked by major environmental changes in Earth's history (atmosphere oxygenation and global glaciations). The origin and the relationships between these events are debated. Sedimentary sequences that record these events have been widely studied in North America (Huronian sequence) and South Africa (Transvaal). An analog sequence in the Pilbara craton in Western Australia (Turee Creek Group, TCG) contains 3 glacial horizons. 3 continental drill cores (Turee Creek Drilling Project, TCDP) were performed in order to investigate the sequence. U-Pb geochronology of monazite and zircon from drill core and surface samples allows to date the first paleoproterozoic glaciation at 2.45 Ga and a second glacial event at ~2.34 Ga. Re-Os analyses of pyrites from the second diamictite yielded an isochron at 2.31 Ga. These results enable to propose a correlation scenario of the paleoproterozoic glacial events recorded on different continents. A 'Snowball Earth' would have occured at 2.45 Ga at least on 5 cratons. A second glaciation could have occured at ~2.31 Ga on 4 cratons. Detrital zircons age spectrum highlights age peaks at 2.45, 2.54, 2.68, 2.82, 2.95 and 3.2 Ga. A crystal of Hadean zircon was discovered and indicate the existence of a probable differentiated crust within the Pilbara craton at 4.0 Ga. 70% of the analyzed zircons have juvenile Hf isotope composition, suggesting that the TCG incorporated volcanic material from continental large igneous provinces through the erosion of the underlying Hamersley and Fortescue groups
La zone de cisaillement de Kandi et le magmatisme associé dans la région de Savalou-Dassa (Bénin) : étude structurale, pétrologique et géochronologique by Luc Adissin Glodji( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

The present study focuses on the structural characteristics of the Kandi shear zone (KSZ) and the time and space relationships between deformation and magmatic events in the central region of Bénin. This tectonic structure is a segment of a lithospheric-scale shear zone that extends from the Hoggar massif (Algeria) to the Atlantic Coast in Bénin and continues down to western Brazil. The present work aims at better understanding the late to post-collision geodynamic evolution of the pan African Dahomeyide fold beltIn summary, this study reveals that the Kandi shear zone in the Central-Bénin is a large (more than 50 km width) dextral transcurrent shear zone, where the latest increments of deformation occur as more localized (kilometric-scale width) shear bands at low temperature. The KSZ activity started at c. 610 Ma and affected the rock basement, including Paleoproterozoic granulites and Neoproterozoic gneisses, migmatites and granitoids. The granitoids intrusions that are spatially associated to the KSZ display ante- to syn-shearing structural features. The earliest intrusion, ante-tectonic Dassa has sub-alkaline affinity deriving from crustal and depleted mantle magmas. This sub-alkaline series carry on during the transcurrent shearing with the Gobada, Tré, Tchetti intrusions. The latest magmatic event of Fita intrusion suggests the transition from sub-alkaline to alkaline magmas, probably reflecting mantle source evolution, from depleted to enriched mantle. We also showed that the Idaho-Mahou volcano-sedimentary basin opened during the transcurrent shearing and the volcanic mafic and felsic rocks are probably related to the successive sub-alkaline to alkaline intrusions. The occurrence of mantle-derived magmas in the shear zone confirms the lithospheric scale of the Kandi shear zone. According to the available radiometric data from the Dahomeyides fold belt, the Kandi shear zone activity seems to contemporaneous with the nappes stacking and thrusting stages in the external orogenic zone (Atacora and western Benin plain) orogen-scale. It also indicates that the KSZ was coeval with the major shear zones from the easternmost region of the Dahomeyides fold belt (NE Nigeria), of the Hoggar and Braziliano belts
Record of mid-Archaean subduction from metamorphism in the Barberton terrain, South Africa by Jean-François Moyen( Book )

1 edition published in 2006 in English and held by 1 WorldCat member library worldwide

Différenciation et stabilisation de la croûte continentale archéenne, l'exemple de la marge Nord du craton du Kaapvaal en Afrique du Sud by Adrien Vezinet( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

The PhD work presented in this manuscript focuses on the recognition and the manifestation of Archean crustal differentiation processes. The Archean eon which represents 1/3 of the geological record is featured by both lithologies unrecognized in younger eons and cryptic geodynamics. Most of investigations concentrate on the characterisation of aluminium-rich lithologies that allow an accurate determination of the pressure-temperature evolution underwent by crustal materials during crustal thickening geodynamics. However, aluminium-rich lithologies - mainly represented by metasediments - account for only 10% on average of Archean terranes whereas orthoderived gneisses - which also testify for crustal differentiation processes - form around 75% of these terranes. The following contribution depicts an Archean composite grey gneiss complex located at the northern edge of the Kaapvaal craton is South Africa. Results carried out during this PhD study have major consequences on Archean geodynamics. The zircon U-Pb/Lu-Hf isotope Investigation coupled with strong petro-metamorphic observations show that composite grey gneiss complexes may be built over a protracted time span, achieved through self-refinement of crustal materials, i.e. the crustal block evolved in a thermodynamically closed system. Grey gneiss compiexes are only moderately investigated even though information enclosed in these lithologies is complementary with those from aluminium-rich rocks. Therefore, deeper investigations of these geological objects must be a central scope in order to improve the knowledge of the Archean eon and appears necessary for the building of even more realistic geotectonic models
Development of new software tools for phase equilibria modelling of open systems by Matthew Mayne( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

The investigation of metamorphic processes in the Earth's crust is integral to understanding the formation and evolution of the Earth. These processes control the preservation potential of the geochronological rock record and give us insight into, amongst others, the pressure and temperature conditions of the Earth's interior. Further, they control fluid generation and consumption within the crust which influences global geochemical cycles within the lithosphere, hydrosphere and atmosphere. This has important implications on the global climate and the creation of conditions conducive to life. The dominant mechanism of change both within and between these systems are compositional changes invoked by processes of mass transfer. Modern quantitative phase equilibrium modelling allows the calculation of the stable phase assemblage of a rock system at equilibrium given its pressure, temperature and bulk chemical composition. However, current software programs have limited functionalities for the sophisticated handling of a changing bulk composition. A new software tool (Rcrust) has been developed that allows the modelling of points in pressure-temperature-bulk composition space in which bulk compositional changes can be passed between points as the system evolves
Rcrust: a tool for calculating path-dependent open system processes and application to melt loss( )

1 edition published in 2016 in English and held by 1 WorldCat member library worldwide

Abstract: Earth's continental crust is stabilized by crustal differentiation that is driven by partial melting and melt loss: Magmas segregate from their residuum and migrate into the upper crust, leaving the deep crust refractory. Thus, compositional change is an integral part of the metamorphic evolution of anatectic granulites. Current thermodynamic modelling techniques have limited abilities to handle changing bulk composition. New software is developed (Rcrust) that via a path-dependent iteration approach enables pressure, temperature and bulk composition to act as simultaneous variables. Path-dependence allows phase additions or extractions that will alter the effective bulk composition of the system. This new methodology leads to a host of additional investigative tools. Singular paths within pressure-temperature-bulk composition (P-T-X) space give details of changing phase proportions and compositions during the anatectic process, while compilations of paths create path-dependent P-T mode diagrams. A case study is used to investigate the effects of melt loss in an open system for a pelite starting bulk composition. The study is expanded upon by considering multiple P-T paths and considering the effects of a lower melt threshold. It is found that, for the pelite starting composition under investigation, open systems produce less melt than closed systems, and that melt loss prior to decompression drastically reduces the ability of the system to form melt upon decompression
Secular changes in tonalite-trondhjemite-granodiorite composition as markers of the progressive cooling of Earth by H Martin( )

1 edition published in 2002 in English and held by 1 WorldCat member library worldwide

 
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WorldCat IdentitiesRelated Identities
Geochemical modelling of igneous processes - principles and recipes in R language : bringing the power of R to a geochemical community
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Archean ganitoids of India : windows into early Earth tectonics / edited by S. Dey and J.-F. Moyen
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J-F Moyen onderzoeker

Moyen, J.-F.

Moyen, J.-F. (Jean-François)

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French (10)

German (1)